Raise libevent dependency to 2.0.10-stable or newer

Only some very ancient distributions don't ship with Libevent 2 anymore,
even the oldest supported Ubuntu LTS version has it. This allows us to
get rid of a lot of compat code.

Makefile.am

@@ -176,7 +176,7 @@ coverage-html-full: all
 	genhtml --branch-coverage -o "$(HTML_COVER_DIR)" "$(HTML_COVER_DIR)/lcov.info"
 
 # Avoid strlcpy.c, strlcat.c, aes.c, OpenBSD_malloc_Linux.c, sha256.c,
-# eventdns.[hc], tinytest*.[ch]
+# tinytest*.[ch]
 check-spaces:
 	$(top_srcdir)/scripts/maint/checkSpace.pl -C \
 		$(top_srcdir)/src/common/*.[ch] \

configure.ac

@@ -481,7 +481,7 @@ TOR_SEARCH_LIBRARY(libevent, $trylibeventdir, [-levent $STATIC_LIBEVENT_FLAGS $T
 #endif
 #include <sys/time.h>
 #include <sys/types.h>
-#include <event.h>], [
+#include <event2/event.h>], [
 #ifdef _WIN32
 #include <winsock2.h>
 #endif
@@ -500,21 +500,10 @@ save_CPPFLAGS="$CPPFLAGS"
 LIBS="-levent $STATIC_LIBEVENT_FLAGS $TOR_LIB_WS32 $LIBS"
 LDFLAGS="$TOR_LDFLAGS_libevent $LDFLAGS"
 CPPFLAGS="$TOR_CPPFLAGS_libevent $CPPFLAGS"
-AC_CHECK_FUNCS([event_get_version_number \
+AC_CHECK_FUNCS([evutil_secure_rng_set_urandom_device_file])
-                evutil_secure_rng_set_urandom_device_file \
-                evutil_secure_rng_init \
-               ])
-AC_CHECK_MEMBERS([struct event.min_heap_idx], , ,
-[#include <event.h>
-])
-
-AC_CHECK_HEADERS(event2/event.h event2/dns.h event2/bufferevent_ssl.h)
 
 LIBS="$STATIC_LIBEVENT_FLAGS $TOR_LIB_WS32 $save_LIBS"
 
-AM_CONDITIONAL(USE_EXTERNAL_EVDNS,
-  test "x$ac_cv_header_event2_dns_h" = "xyes")
-
 if test "$enable_static_libevent" = "yes"; then
    if test "$tor_cv_library_libevent_dir" = "(system)"; then
      AC_MSG_ERROR("You must specify an explicit --with-libevent-dir=x option when using --enable-static-libevent")
@@ -541,32 +530,34 @@ LIBS="$save_LIBS"
 LDFLAGS="$save_LDFLAGS"
 CPPFLAGS="$save_CPPFLAGS"
 
-dnl This isn't the best test for Libevent 2.0.3-alpha.  Once it's released,
+dnl Check that libevent is at least at version 2.0.10, the first stable
-dnl we can do much better.
+dnl release of its series
-if test "$enable_bufferevents" = "yes"; then
+CPPFLAGS="$CPPFLAGS $TOR_CPPFLAGS_libevent"
-  if test "$ac_cv_header_event2_bufferevent_ssl_h" != "yes"; then
+AC_MSG_CHECKING([whether Libevent is new enough])
-    AC_MSG_ERROR([You've asked for bufferevent support, but you're using a version of Libevent without SSL support.  This won't work.  We need Libevent 2.0.8-rc or later, and you don't seem to even have Libevent 2.0.3-alpha.])
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([
-  else
-
-    CPPFLAGS="$CPPFLAGS $TOR_CPPFLAGS_libevent"
-
-    # Check for the right version.  First see if version detection works.
-    AC_MSG_CHECKING([whether we can detect the Libevent version])
-    AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 #include <event2/event.h>
-#if !defined(LIBEVENT_VERSION_NUMBER) || LIBEVENT_VERSION_NUMBER < 10
+#if !defined(LIBEVENT_VERSION_NUMBER) || LIBEVENT_VERSION_NUMBER < 0x02000a00
 #error
 int x = y(zz);
 #else
 int x = 1;
 #endif
-  ])], [event_version_number_works=yes; AC_MSG_RESULT([yes]) ],
+])], [ AC_MSG_RESULT([yes]) ],
-     [event_version_number_works=no;  AC_MSG_RESULT([no])])
+   [ AC_MSG_RESULT([no])
-    if test "$event_version_number_works" != "yes"; then
+     AC_MSG_ERROR([Libevent is not new enough.  We require 2.0.10-stable or later]) ] )
-      AC_MSG_WARN([Version detection on Libevent seems broken.  Your Libevent installation is probably screwed up or very old.])
+
-    else
+LIBS="$save_LIBS"
-      AC_MSG_CHECKING([whether Libevent is new enough for bufferevents])
+LDFLAGS="$save_LDFLAGS"
-      AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+CPPFLAGS="$save_CPPFLAGS"
+
+dnl bufferents require version 2.0.13
+if test "$enable_bufferevents" = "yes"; then
+   AC_CHECK_HEADERS(event2/bufferevent_ssl.h)
+
+   CPPFLAGS="$CPPFLAGS $TOR_CPPFLAGS_libevent"
+
+   AC_MSG_CHECKING([whether Libevent is new enough for bufferevents])
+   AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 #include <event2/event.h>
 #if !defined(LIBEVENT_VERSION_NUMBER) || LIBEVENT_VERSION_NUMBER < 0x02000d00
 #error
@@ -577,8 +568,6 @@ int x = 1;
    ])], [ AC_MSG_RESULT([yes]) ],
       [ AC_MSG_RESULT([no])
         AC_MSG_ERROR([Libevent does not seem new enough to support bufferevents.  We require 2.0.13-stable or later]) ] )
-    fi
-  fi
 fi
 
 LIBS="$save_LIBS"

scripts/maint/redox.py

@@ -33,8 +33,6 @@
 # files that we've snarfed in from somebody else, whose C we do no intend
 # to document for them.
 SKIP_FILES = [ "OpenBSD_malloc_Linux.c",
-               "eventdns.c",
-               "eventdns.h",
                "strlcat.c",
                "strlcpy.c",
                "sha256.c",

src/common/compat_libevent.c

@@ -19,15 +19,11 @@
 #include "util.h"
 #include "torlog.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
 #include <event2/thread.h>
 #ifdef USE_BUFFEREVENTS
 #include <event2/bufferevent.h>
 #endif
-#else
-#include <event.h>
-#endif
 
 /** A string which, if it appears in a libevent log, should be ignored. */
 static const char *suppress_msg = NULL;
@@ -69,6 +65,7 @@ configure_libevent_logging(void)
 {
   event_set_log_callback(libevent_logging_callback);
 }
+
 /** Ignore any libevent log message that contains <b>msg</b>. */
 void
 suppress_libevent_log_msg(const char *msg)
@@ -76,44 +73,6 @@ suppress_libevent_log_msg(const char *msg)
   suppress_msg = msg;
 }
 
-#ifndef HAVE_EVENT2_EVENT_H
-/** Work-alike replacement for event_new() on pre-Libevent-2.0 systems. */
-struct event *
-tor_event_new(struct event_base *base, int sock, short what,
-              void (*cb)(int, short, void *), void *arg)
-{
-  struct event *e = tor_malloc_zero(sizeof(struct event));
-  event_set(e, sock, what, cb, arg);
-  if (! base)
-    base = tor_libevent_get_base();
-  event_base_set(base, e);
-  return e;
-}
-/** Work-alike replacement for evtimer_new() on pre-Libevent-2.0 systems. */
-struct event *
-tor_evtimer_new(struct event_base *base,
-                void (*cb)(int, short, void *), void *arg)
-{
-  return tor_event_new(base, -1, 0, cb, arg);
-}
-/** Work-alike replacement for evsignal_new() on pre-Libevent-2.0 systems. */
-struct event *
-tor_evsignal_new(struct event_base * base, int sig,
-                 void (*cb)(int, short, void *), void *arg)
-{
-  return tor_event_new(base, sig, EV_SIGNAL|EV_PERSIST, cb, arg);
-}
-/** Work-alike replacement for event_free() on pre-Libevent-2.0 systems,
- * except tolerate tor_event_free(NULL). */
-void
-tor_event_free(struct event *ev)
-{
-  if (ev == NULL)
-    return;
-  event_del(ev);
-  tor_free(ev);
-}
-#else
 /* Wrapper for event_free() that tolerates tor_event_free(NULL) */
 void
 tor_event_free(struct event *ev)
@@ -122,7 +81,6 @@ tor_event_free(struct event *ev)
     return;
   event_free(ev);
 }
-#endif
 
 /** Global event base for use by the main thread. */
 static struct event_base *the_event_base = NULL;
@@ -158,7 +116,6 @@ tor_libevent_initialize(tor_libevent_cfg *torcfg)
   /* some paths below don't use torcfg, so avoid unused variable warnings */
   (void)torcfg;
 
-#ifdef HAVE_EVENT2_EVENT_H
   {
     int attempts = 0;
     int using_threads;
@@ -190,16 +147,12 @@ tor_libevent_initialize(tor_libevent_cfg *torcfg)
       event_config_set_flag(cfg, EVENT_BASE_FLAG_NOLOCK);
     }
 
-#if defined(LIBEVENT_VERSION_NUMBER) && LIBEVENT_VERSION_NUMBER >= V(2,0,7)
     if (torcfg->num_cpus > 0)
       event_config_set_num_cpus_hint(cfg, torcfg->num_cpus);
-#endif
 
-#if LIBEVENT_VERSION_NUMBER >= V(2,0,9)
     /* We can enable changelist support with epoll, since we don't give
      * Libevent any dup'd fds.  This lets us avoid some syscalls. */
     event_config_set_flag(cfg, EVENT_BASE_FLAG_EPOLL_USE_CHANGELIST);
-#endif
 
     the_event_base = event_base_new_with_config(cfg);
 
@@ -223,9 +176,6 @@ tor_libevent_initialize(tor_libevent_cfg *torcfg)
       goto retry;
     }
   }
-#else
-  the_event_base = event_init();
-#endif
 
   if (!the_event_base) {
     /* LCOV_EXCL_START */
@@ -255,62 +205,7 @@ tor_libevent_get_base, (void))
 const char *
 tor_libevent_get_method(void)
 {
-#ifdef HAVE_EVENT2_EVENT_H
   return event_base_get_method(the_event_base);
-#else
-  return event_get_method();
-#endif
-}
-
-/** Return the le_version_t for the version of libevent specified in the
- * string <b>v</b>.  If the version is very new or uses an unrecognized
- * version, format, return LE_OTHER. */
-STATIC le_version_t
-tor_decode_libevent_version(const char *v)
-{
-  unsigned major, minor, patchlevel;
-  char c, e, extra;
-  int fields;
-
-  /* Try the new preferred "1.4.11-stable" format.
-   * Also accept "1.4.14b-stable". */
-  fields = tor_sscanf(v, "%u.%u.%u%c%c", &major, &minor, &patchlevel, &c, &e);
-  if (fields == 3 ||
-      ((fields == 4 || fields == 5 ) && (c == '-' || c == '_')) ||
-      (fields == 5 && TOR_ISALPHA(c) && (e == '-' || e == '_'))) {
-    return V(major,minor,patchlevel);
-  }
-
-  /* Try the old "1.3e" format. */
-  fields = tor_sscanf(v, "%u.%u%c%c", &major, &minor, &c, &extra);
-  if (fields == 3 && TOR_ISALPHA(c)) {
-    return V_OLD(major, minor, c);
-  } else if (fields == 2) {
-    return V(major, minor, 0);
-  }
-
-  return LE_OTHER;
-}
-
-/** Return an integer representing the binary interface of a Libevent library.
- * Two different versions with different numbers are sure not to be binary
- * compatible.  Two different versions with the same numbers have a decent
- * chance of binary compatibility.*/
-STATIC int
-le_versions_compatibility(le_version_t v)
-{
-  if (v == LE_OTHER)
-    return 0;
-  if (v < V_OLD(1,0,'c'))
-    return 1;
-  else if (v < V(1,4,0))
-    return 2;
-  else if (v < V(1,4,99))
-    return 3;
-  else if (v < V(2,0,1))
-    return 4;
-  else /* Everything 2.0 and later should be compatible. */
-    return 5;
 }
 
 /** Return a string representation of the version of the currently running
@@ -321,101 +216,14 @@ tor_libevent_get_version_str(void)
   return event_get_version();
 }
 
-#if defined(LIBEVENT_VERSION)
-#define HEADER_VERSION LIBEVENT_VERSION
-#elif defined(_EVENT_VERSION)
-#define HEADER_VERSION _EVENT_VERSION
-#endif
-
 /** Return a string representation of the version of Libevent that was used
 * at compilation time. */
 const char *
 tor_libevent_get_header_version_str(void)
 {
-  return HEADER_VERSION;
+  return LIBEVENT_VERSION;
-}
-
-/** See whether the headers we were built against differ from the library we
- * linked against so much that we're likely to crash.  If so, warn the
- * user. */
-void
-tor_check_libevent_header_compatibility(void)
-{
-  (void) le_versions_compatibility;
-  (void) tor_decode_libevent_version;
-
-  /* In libevent versions before 2.0, it's hard to keep binary compatibility
-   * between upgrades, and unpleasant to detect when the version we compiled
-   * against is unlike the version we have linked against. Here's how. */
-#if defined(HEADER_VERSION)
-  /* We have a header-file version and a function-call version. Easy. */
-  if (strcmp(HEADER_VERSION, event_get_version())) {
-    le_version_t v1, v2;
-    int compat1 = -1, compat2 = -1;
-    int verybad;
-    v1 = tor_decode_libevent_version(HEADER_VERSION);
-    v2 = tor_decode_libevent_version(event_get_version());
-    compat1 = le_versions_compatibility(v1);
-    compat2 = le_versions_compatibility(v2);
-
-    verybad = compat1 != compat2;
-
-    tor_log(verybad ? LOG_WARN : LOG_NOTICE,
-        LD_GENERAL, "We were compiled with headers from version %s "
-        "of Libevent, but we're using a Libevent library that says it's "
-        "version %s.", HEADER_VERSION, event_get_version());
-    if (verybad)
-      log_warn(LD_GENERAL, "This will almost certainly make Tor crash.");
-    else
-      log_info(LD_GENERAL, "I think these versions are binary-compatible.");
-  }
-#else
-  /* event_get_version but no _EVENT_VERSION.  We might be in 1.4.0-beta or
-     earlier, where that's normal.  To see whether we were compiled with an
-     earlier version, let's see whether the struct event defines MIN_HEAP_IDX.
-  */
-#ifdef HAVE_STRUCT_EVENT_MIN_HEAP_IDX
-  /* The header files are 1.4.0-beta or later. If the version is not
-   * 1.4.0-beta, we are incompatible. */
-  {
-    if (strcmp(event_get_version(), "1.4.0-beta")) {
-      log_warn(LD_GENERAL, "It's a little hard to tell, but you seem to have "
-               "Libevent 1.4.0-beta header files, whereas you have linked "
-               "against Libevent %s.  This will probably make Tor crash.",
-               event_get_version());
-    }
-  }
-#else
-  /* Our headers are 1.3e or earlier. If the library version is not 1.4.x or
-     later, we're probably fine. */
-  {
-    const char *v = event_get_version();
-    if ((v[0] == '1' && v[2] == '.' && v[3] > '3') || v[0] > '1') {
-      log_warn(LD_GENERAL, "It's a little hard to tell, but you seem to have "
-               "Libevent header file from 1.3e or earlier, whereas you have "
-               "linked against Libevent %s.  This will probably make Tor "
-               "crash.", event_get_version());
-    }
-  }
-#endif
-
-  /* Your libevent is ancient. */
-#endif
 }
 
-/*
-  If possible, we're going to try to use Libevent's periodic timer support,
-  since it does a pretty good job of making sure that periodic events get
-  called exactly M seconds apart, rather than starting each one exactly M
-  seconds after the time that the last one was run.
- */
-#ifdef HAVE_EVENT2_EVENT_H
-#define HAVE_PERIODIC
-#define PERIODIC_FLAGS EV_PERSIST
-#else
-#define PERIODIC_FLAGS 0
-#endif
-
 /** Represents a timer that's run every N microseconds by Libevent. */
 struct periodic_timer_t {
   /** Underlying event used to implement this periodic event. */
@@ -424,11 +232,6 @@ struct periodic_timer_t {
   void (*cb)(struct periodic_timer_t *, void *);
   /** User-supplied data for the callback */
   void *data;
-#ifndef HAVE_PERIODIC
-  /** If Libevent doesn't know how to invoke events every N microseconds,
-   * we'll need to remember the timeout interval here. */
-  struct timeval tv;
-#endif
 };
 
 /** Libevent callback to implement a periodic event. */
@@ -438,10 +241,6 @@ periodic_timer_cb(evutil_socket_t fd, short what, void *arg)
   periodic_timer_t *timer = arg;
   (void) what;
   (void) fd;
-#ifndef HAVE_PERIODIC
-  /** reschedule the event as needed. */
-  event_add(timer->ev, &timer->tv);
-#endif
   timer->cb(timer, timer->data);
 }
 
@@ -459,16 +258,13 @@ periodic_timer_new(struct event_base *base,
   tor_assert(tv);
   tor_assert(cb);
   timer = tor_malloc_zero(sizeof(periodic_timer_t));
-  if (!(timer->ev = tor_event_new(base, -1, PERIODIC_FLAGS,
+  if (!(timer->ev = tor_event_new(base, -1, EV_PERSIST,
                                   periodic_timer_cb, timer))) {
     tor_free(timer);
     return NULL;
   }
   timer->cb = cb;
   timer->data = data;
-#ifndef HAVE_PERIODIC
-  memcpy(&timer->tv, tv, sizeof(struct timeval));
-#endif
   event_add(timer->ev, (struct timeval *)tv); /*drop const for old libevent*/
   return timer;
 }
@@ -539,7 +335,6 @@ int
 tor_init_libevent_rng(void)
 {
   int rv = 0;
-#ifdef HAVE_EVUTIL_SECURE_RNG_INIT
   char buf[256];
   if (evutil_secure_rng_init() < 0) {
     rv = -1;
@@ -547,7 +342,6 @@ tor_init_libevent_rng(void)
   crypto_rand(buf, 32);
   evutil_secure_rng_add_bytes(buf, 32);
   evutil_secure_rng_get_bytes(buf, sizeof(buf));
-#endif
   return rv;
 }
 

src/common/compat_libevent.h

@@ -15,32 +15,17 @@ struct ev_token_bucket_cfg;
 struct bufferevent_rate_limit_group;
 #endif
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/util.h>
-#elif !defined(EVUTIL_SOCKET_DEFINED)
-#define EVUTIL_SOCKET_DEFINED
-#define evutil_socket_t int
-#endif
 
 void configure_libevent_logging(void);
 void suppress_libevent_log_msg(const char *msg);
 
-#ifdef HAVE_EVENT2_EVENT_H
 #define tor_event_new     event_new
 #define tor_evtimer_new   evtimer_new
 #define tor_evsignal_new  evsignal_new
 #define tor_evdns_add_server_port(sock, tcp, cb, data) \
   evdns_add_server_port_with_base(tor_libevent_get_base(), \
   (sock),(tcp),(cb),(data));
-#else
-struct event *tor_event_new(struct event_base * base, evutil_socket_t sock,
-           short what, void (*cb)(evutil_socket_t, short, void *), void *arg);
-struct event *tor_evtimer_new(struct event_base * base,
-            void (*cb)(evutil_socket_t, short, void *), void *arg);
-struct event *tor_evsignal_new(struct event_base * base, int sig,
-            void (*cb)(evutil_socket_t, short, void *), void *arg);
-#define tor_evdns_add_server_port evdns_add_server_port
-#endif
 
 void tor_event_free(struct event *ev);
 
@@ -99,9 +84,7 @@ void tor_gettimeofday_cached_monotonic(struct timeval *tv);
     byte is unused.
 
     This is equivalent to the format of LIBEVENT_VERSION_NUMBER on Libevent
-    2.0.1 or later.  For versions of Libevent before 1.4.0, which followed the
+    2.0.1 or later.
-    format of "1.0, 1.0a, 1.0b", we define 1.0 to be equivalent to 1.0.0, 1.0a
-    to be equivalent to 1.0.1, and so on.
 */
 typedef uint32_t le_version_t;
 
@@ -109,23 +92,10 @@ typedef uint32_t le_version_t;
 /** Macros: returns the number of a libevent version as a le_version_t */
 #define V(major, minor, patch) \
   (((major) << 24) | ((minor) << 16) | ((patch) << 8))
-#define V_OLD(major, minor, patch) \
-  V((major), (minor), (patch)-'a'+1)
 /** @} */
 
-/** Represetns a version of libevent so old we can't figure out what version
- * it is. */
-#define LE_OLD V(0,0,0)
-/** Represents a version of libevent so weird we can't figure out what version
- * it is. */
-#define LE_OTHER V(0,0,99)
-
 STATIC void
 libevent_logging_callback(int severity, const char *msg);
-STATIC le_version_t
-tor_decode_libevent_version(const char *v);
-STATIC int
-le_versions_compatibility(le_version_t v);
 #endif
 
 #endif

src/common/procmon.c

@@ -10,11 +10,7 @@
 
 #include "util.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 #ifdef HAVE_SIGNAL_H
 #include <signal.h>
@@ -164,11 +160,7 @@ tor_validate_process_specifier(const char *process_spec,
 }
 
 /* XXXX we should use periodic_timer_new() for this stuff */
-#ifdef HAVE_EVENT2_EVENT_H
 #define PERIODIC_TIMER_FLAGS EV_PERSIST
-#else
-#define PERIODIC_TIMER_FLAGS (0)
-#endif
 
 /* DOCDOC poll_interval_tv */
 static struct timeval poll_interval_tv = {15, 0};
@@ -331,10 +323,6 @@ tor_process_monitor_poll_cb(evutil_socket_t unused1, short unused2,
 
   if (its_dead_jim) {
     procmon->cb(procmon->cb_arg);
-#ifndef HAVE_EVENT2_EVENT_H
-  } else {
-    evtimer_add(procmon->e, &poll_interval_tv);
-#endif
   }
 }
 #endif

src/common/timers.c

@@ -38,11 +38,7 @@
 #include "torlog.h"
 #include "util.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 struct timeout_cb {
   timer_cb_fn_t cb;

src/ext/README

@@ -11,13 +11,6 @@ strlcpy.c
     for strcat and strcpy.  These are nonstandard, and some libc
     implementations refuse to add them for religious reasons.
 
-eventdns.[ch]
-
-    A fork of Libevent's DNS implementation, used by Tor when Libevent
-    2.0 or later is not available.  Once Libevent 2.0 is required, we
-    should throw this away; it has diverged from evdns.[ch], and is
-    no longer easily mergeable.
-
 ht.h
 
     An implementation of a hash table in the style of Niels Provos's

src/ext/eventdns.c

@@ -1,3514 +0,0 @@
-/* READ THIS COMMENT BEFORE HACKING THIS FILE.
- *
- * This eventdns.c copy has diverged a bit from Libevent's version, and it's
- * no longer easy to resynchronize them.  Once Tor requires Libevent 2.0, we
- * will just dump this file and use Libevent's evdns code.
- *
- * Therefore, you probably shouldn't make any change here without making it to
- * Libevent as well: it's not good for the implementation to diverge even
- * more.  Also, we can't shouldn't wantonly the API here (since Libevent APIs
- * can't change in ways that break user behavior).  Also, we shouldn't bother
- * with cosmetic changes: the whole module is slated for demolition, so
- * there's no point dusting the linebreaks or re-painting the parser.
- *
- * (We can't just drop the Libevent 2.0 evdns implementation in here instead,
- * since it depends pretty heavily on parts of Libevent 2.0.)
- */
-
-/* Async DNS Library
- * Adam Langley <agl@imperialviolet.org>
- * Public Domain code
- *
- * This software is Public Domain. To view a copy of the public domain dedication,
- * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
- * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
- *
- * I ask and expect, but do not require, that all derivative works contain an
- * attribution similar to:
- *	Parts developed by Adam Langley <agl@imperialviolet.org>
- *
- * You may wish to replace the word "Parts" with something else depending on
- * the amount of original code.
- *
- * (Derivative works does not include programs which link against, run or include
- * the source verbatim in their source distributions)
- *
- * Version: 0.1b
- */
-
-#include "eventdns_tor.h"
-#include "util.h"
-#include <sys/types.h>
-/* #define NDEBUG */
-
-#ifndef DNS_USE_CPU_CLOCK_FOR_ID
-#ifndef DNS_USE_GETTIMEOFDAY_FOR_ID
-#ifndef DNS_USE_OPENSSL_FOR_ID
-#error Must configure at least one id generation method.
-#error Please see the documentation.
-#endif
-#endif
-#endif
-
-#ifdef DNS_USE_CPU_CLOCK_FOR_ID
-#ifdef DNS_USE_OPENSSL_FOR_ID
-#error Multiple id options selected
-#endif
-#ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
-#error Multiple id options selected
-#endif
-#include <time.h>
-#endif
-
-#ifdef DNS_USE_OPENSSL_FOR_ID
-#ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
-#error Multiple id options selected
-#endif
-#include <openssl/rand.h>
-#endif
-
-#include <string.h>
-#ifdef HAVE_FCNTL_H
-#include <fcntl.h>
-#endif
-#ifdef HAVE_SYS_TIME_H
-#include <sys/time.h>
-#endif
-#ifdef HAVE_STDINT_H
-#include <stdint.h>
-#endif
-#include <stdlib.h>
-#include <errno.h>
-#include <assert.h>
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-#ifdef HAVE_LIMITS_H
-#include <limits.h>
-#endif
-#include <sys/stat.h>
-#include <ctype.h>
-#include <stdio.h>
-#include <stdarg.h>
-
-#include "eventdns.h"
-
-#ifdef _WIN32
-#include <windows.h>
-#include <winsock2.h>
-#include <iphlpapi.h>
-#else
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#endif
-
-#ifdef HAVE_NETINET_IN6_H
-#include <netinet/in6.h>
-#endif
-
-#ifdef _WIN32
-typedef int socklen_t;
-#endif
-
-#define EVDNS_LOG_DEBUG 0
-#define EVDNS_LOG_WARN 1
-
-#ifndef HOST_NAME_MAX
-#define HOST_NAME_MAX 255
-#endif
-
-#ifndef NDEBUG
-#include <stdio.h>
-#endif
-
-/* for debugging possible memory leaks. */
-#define mm_malloc(x) tor_malloc(x)
-#define mm_realloc(x,y) tor_realloc((x),(y))
-#define mm_free(x) tor_free(x)
-#define mm_strdup(x) tor_strdup(x)
-#define _mm_free(x) tor_free_(x)
-
-#undef MIN
-#define MIN(a,b) ((a)<(b)?(a):(b))
-
-#if 0
-#ifdef __USE_ISOC99B
-/* libevent doesn't work without this */
-typedef uint8_t u_char;
-typedef unsigned int uint;
-#endif
-#endif
-#include <event.h>
-
-#define u64 uint64_t
-#define u32 uint32_t
-#define u16 uint16_t
-#define u8	uint8_t
-
-#define MAX_ADDRS 4	 /* maximum number of addresses from a single packet */
-/* which we bother recording */
-
-#define TYPE_A		EVDNS_TYPE_A
-#define TYPE_CNAME	5
-#define TYPE_PTR	EVDNS_TYPE_PTR
-#define TYPE_AAAA	EVDNS_TYPE_AAAA
-
-#define CLASS_INET	EVDNS_CLASS_INET
-
-#define CLEAR(x) do { memset((x), 0xF0, sizeof(*(x))); } while(0)
-
-struct evdns_request {
-	u8 *request; /* the dns packet data */
-	unsigned int request_len;
-	int reissue_count;
-	int tx_count;  /* the number of times that this packet has been sent */
-	unsigned int request_type; /* TYPE_PTR or TYPE_A */
-	void *user_pointer;	 /* the pointer given to us for this request */
-	evdns_callback_type user_callback;
-	struct nameserver *ns;	/* the server which we last sent it */
-
-	/* elements used by the searching code */
-	int search_index;
-	struct search_state *search_state;
-	char *search_origname;	/* needs to be mm_free()ed */
-	int search_flags;
-
-	/* these objects are kept in a circular list */
-	struct evdns_request *next, *prev;
-
-	struct event timeout_event;
-
-	u16 trans_id;  /* the transaction id */
-	char request_appended;	/* true if the request pointer is data which follows this struct */
-	char transmit_me;  /* needs to be transmitted */
-};
-
-#ifndef HAVE_STRUCT_IN6_ADDR
-struct in6_addr {
-	u8 s6_addr[16];
-};
-#endif
-
-struct reply {
-	unsigned int type;
-	unsigned int have_answer;
-	union {
-		struct {
-			u32 addrcount;
-			u32 addresses[MAX_ADDRS];
-		} a;
-		struct {
-			u32 addrcount;
-			struct in6_addr addresses[MAX_ADDRS];
-		} aaaa;
-		struct {
-			char name[HOST_NAME_MAX];
-		} ptr;
-	} data;
-};
-
-struct nameserver {
-	int socket;	 /* a connected UDP socket */
-	struct sockaddr_storage address;
-	int failed_times;  /* number of times which we have given this server a chance */
-	int timedout;  /* number of times in a row a request has timed out */
-	struct event event;
-	/* these objects are kept in a circular list */
-	struct nameserver *next, *prev;
-	struct event timeout_event; /* used to keep the timeout for */
-								/* when we next probe this server. */
-								/* Valid if state == 0 */
-	char state;	 /* zero if we think that this server is down */
-	char choked;  /* true if we have an EAGAIN from this server's socket */
-	char write_waiting;	 /* true if we are waiting for EV_WRITE events */
-};
-
-static struct evdns_request *req_head = NULL, *req_waiting_head = NULL;
-static struct nameserver *server_head = NULL;
-
-/* Represents a local port where we're listening for DNS requests. Right now, */
-/* only UDP is supported. */
-struct evdns_server_port {
-	int socket; /* socket we use to read queries and write replies. */
-	int refcnt; /* reference count. */
-	char choked; /* Are we currently blocked from writing? */
-	char closing; /* Are we trying to close this port, pending writes? */
-	evdns_request_callback_fn_type user_callback; /* Fn to handle requests */
-	void *user_data; /* Opaque pointer passed to user_callback */
-	struct event event; /* Read/write event */
-	/* circular list of replies that we want to write. */
-	struct server_request *pending_replies;
-};
-
-/* Represents part of a reply being built.	(That is, a single RR.) */
-struct server_reply_item {
-	struct server_reply_item *next; /* next item in sequence. */
-	char *name; /* name part of the RR */
-	u16 type : 16; /* The RR type */
-	u16 class : 16; /* The RR class (usually CLASS_INET) */
-	u32 ttl; /* The RR TTL */
-	char is_name; /* True iff data is a label */
-	u16 datalen; /* Length of data; -1 if data is a label */
-	void *data; /* The contents of the RR */
-};
-
-/* Represents a request that we've received as a DNS server, and holds */
-/* the components of the reply as we're constructing it. */
-struct server_request {
-	/* Pointers to the next and previous entries on the list of replies */
-	/* that we're waiting to write.	 Only set if we have tried to respond */
-	/* and gotten EAGAIN. */
-	struct server_request *next_pending;
-	struct server_request *prev_pending;
-
-	u16 trans_id; /* Transaction id. */
-	struct evdns_server_port *port; /* Which port received this request on? */
-	struct sockaddr_storage addr; /* Where to send the response */
-	socklen_t addrlen; /* length of addr */
-
-	int n_answer; /* how many answer RRs have been set? */
-	int n_authority; /* how many authority RRs have been set? */
-	int n_additional; /* how many additional RRs have been set? */
-
-	struct server_reply_item *answer; /* linked list of answer RRs */
-	struct server_reply_item *authority; /* linked list of authority RRs */
-	struct server_reply_item *additional; /* linked list of additional RRs */
-
-	/* Constructed response.  Only set once we're ready to send a reply. */
-	/* Once this is set, the RR fields are cleared, and no more should be set. */
-	char *response;
-	size_t response_len;
-
-	/* Caller-visible fields: flags, questions. */
-	struct evdns_server_request base;
-};
-
-/* helper macro */
-#define OFFSET_OF(st, member) ((off_t) (((char*)&((st*)0)->member)-(char*)0))
-
-/* Given a pointer to an evdns_server_request, get the corresponding */
-/* server_request. */
-#define TO_SERVER_REQUEST(base_ptr)										\
-	((struct server_request*)											\
-	 (((char*)(base_ptr) - OFFSET_OF(struct server_request, base))))
-
-/* The number of good nameservers that we have */
-static int global_good_nameservers = 0;
-
-/* inflight requests are contained in the req_head list */
-/* and are actually going out across the network */
-static int global_requests_inflight = 0;
-/* requests which aren't inflight are in the waiting list */
-/* and are counted here */
-static int global_requests_waiting = 0;
-
-static int global_max_requests_inflight = 64;
-
-static struct timeval global_timeout = {5, 0};	/* 5 seconds */
-static int global_max_reissues = 1;	/* a reissue occurs when we get some errors from the server */
-static int global_max_retransmits = 3;	/* number of times we'll retransmit a request which timed out */
-/* number of timeouts in a row before we consider this server to be down */
-static int global_max_nameserver_timeout = 3;
-
-/* true iff we should use the 0x20 hack. */
-static int global_randomize_case = 1;
-
-/* These are the timeout values for nameservers. If we find a nameserver is down */
-/* we try to probe it at intervals as given below. Values are in seconds. */
-static const struct timeval global_nameserver_timeouts[] = {{10, 0}, {60, 0}, {300, 0}, {900, 0}, {3600, 0}};
-static const int global_nameserver_timeouts_length = (int)(sizeof(global_nameserver_timeouts)/sizeof(struct timeval));
-
-static struct nameserver *nameserver_pick(void);
-static void evdns_request_insert(struct evdns_request *req, struct evdns_request **head);
-static void nameserver_ready_callback(int fd, short events, void *arg);
-static int evdns_transmit(void);
-static int evdns_request_transmit(struct evdns_request *req);
-static void nameserver_send_probe(struct nameserver *const ns);
-static void search_request_finished(struct evdns_request *const);
-static int search_try_next(struct evdns_request *const req);
-static int search_request_new(int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg);
-static void evdns_requests_pump_waiting_queue(void);
-static u16 transaction_id_pick(void);
-static struct evdns_request *request_new(int type, const char *name, int flags, evdns_callback_type callback, void *ptr);
-static void request_submit(struct evdns_request *req);
-
-static int server_request_free(struct server_request *req);
-static void server_request_free_answers(struct server_request *req);
-static void server_port_free(struct evdns_server_port *port);
-static void server_port_ready_callback(int fd, short events, void *arg);
-
-static int strtoint(const char *const str);
-
-#ifdef _WIN32
-static int
-last_error(int sock)
-{
-	int optval, optvallen=sizeof(optval);
-	int err = WSAGetLastError();
-	if (err == WSAEWOULDBLOCK && sock >= 0) {
-		if (getsockopt(sock, SOL_SOCKET, SO_ERROR, (void*)&optval,
-					   &optvallen))
-			return err;
-		if (optval)
-			return optval;
-	}
-	return err;
-
-}
-static int
-error_is_eagain(int err)
-{
-	return err == EAGAIN || err == WSAEWOULDBLOCK;
-}
-#define inet_aton(c, addr) tor_inet_aton((c), (addr))
-#define CLOSE_SOCKET(x) closesocket(x)
-#else
-#define last_error(sock) (errno)
-#if EAGAIN != EWOULDBLOCK
-#define error_is_eagain(err) ((err) == EAGAIN || (err) == EWOULDBLOCK)
-#else
-#define error_is_eagain(err) ((err) == EAGAIN)
-#endif
-#define CLOSE_SOCKET(x) close(x)
-#endif
-
-#define ISSPACE(c) TOR_ISSPACE(c)
-#define ISDIGIT(c) TOR_ISDIGIT(c)
-#define ISALPHA(c) TOR_ISALPHA(c)
-#define TOLOWER(c) TOR_TOLOWER(c)
-#define TOUPPER(c) TOR_TOUPPER(c)
-
-#ifndef NDEBUG
-static const char *
-debug_ntoa(u32 address)
-{
-	static char buf[32];
-	u32 a = ntohl(address);
-	tor_snprintf(buf, sizeof(buf), "%d.%d.%d.%d",
-			(int)(u8)((a>>24)&0xff),
-			(int)(u8)((a>>16)&0xff),
-			(int)(u8)((a>>8 )&0xff),
-			(int)(u8)((a	)&0xff));
-	return buf;
-}
-static const char *
-debug_ntop(const struct sockaddr *sa)
-{
-	if (sa->sa_family == AF_INET) {
-		struct sockaddr_in *sin = (struct sockaddr_in *) sa;
-		return debug_ntoa(sin->sin_addr.s_addr);
-	}
-	if (sa->sa_family == AF_INET6) {
-		/* Tor-specific.  In libevent, add more check code. */
-		static char buf[128];
-		struct sockaddr_in6 *sin = (struct sockaddr_in6 *) sa;
-		tor_inet_ntop(AF_INET6, &sin->sin6_addr, buf, sizeof(buf));
-		return buf;
-	}
-	return "<unknown>";
-}
-#endif
-
-static evdns_debug_log_fn_type evdns_log_fn = NULL;
-
-void
-evdns_set_log_fn(evdns_debug_log_fn_type fn)
-{
-	evdns_log_fn = fn;
-}
-
-#ifdef __GNUC__
-#define EVDNS_LOG_CHECK	__attribute__ ((format(printf, 2, 3)))
-#else
-#define EVDNS_LOG_CHECK
-#endif
-
-static void evdns_log(int warn, const char *fmt, ...) EVDNS_LOG_CHECK;
-static void
-evdns_log(int warn, const char *fmt, ...)
-{
-	va_list args;
-	static char buf[512];
-	if (!evdns_log_fn)
-		return;
-	va_start(args,fmt);
-	tor_vsnprintf(buf, sizeof(buf), fmt, args);
-	evdns_log_fn(warn, buf);
-	va_end(args);
-}
-
-static int
-sockaddr_eq(const struct sockaddr *sa1, const struct sockaddr *sa2,
-			int include_port)
-{
-	if (sa1->sa_family != sa2->sa_family)
-		return 0;
-	if (sa1->sa_family == AF_INET) {
-		const struct sockaddr_in *sin1, *sin2;
-		sin1 = (const struct sockaddr_in *)sa1;
-		sin2 = (const struct sockaddr_in *)sa2;
-		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
-			return 0;
-		else if (include_port && sin1->sin_port != sin2->sin_port)
-			return 0;
-		else
-			return 1;
-	}
-#ifdef AF_INET6
-	if (sa1->sa_family == AF_INET6) {
-		const struct sockaddr_in6 *sin1, *sin2;
-		sin1 = (const struct sockaddr_in6 *)sa1;
-		sin2 = (const struct sockaddr_in6 *)sa2;
-		if (tor_memneq(sin1->sin6_addr.s6_addr, sin2->sin6_addr.s6_addr, 16))
-			return 0;
-		else if (include_port && sin1->sin6_port != sin2->sin6_port)
-			return 0;
-		else
-			return 1;
-	}
-#endif
-	return 1;
-}
-
-#define add_timeout_event(s, to)				\
-	(event_add(&(s)->timeout_event, (to)))
-#define del_timeout_event(s)					\
-	(event_del(&(s)->timeout_event))
-
-/* This walks the list of inflight requests to find the */
-/* one with a matching transaction id. Returns NULL on */
-/* failure */
-static struct evdns_request *
-request_find_from_trans_id(u16 trans_id) {
-	struct evdns_request *req = req_head, *const started_at = req_head;
-
-	if (req) {
-		do {
-			if (req->trans_id == trans_id) return req;
-			req = req->next;
-		} while (req != started_at);
-	}
-
-	return NULL;
-}
-
-/* a libevent callback function which is called when a nameserver */
-/* has gone down and we want to test if it has came back to life yet */
-static void
-nameserver_prod_callback(int fd, short events, void *arg) {
-	struct nameserver *const ns = (struct nameserver *) arg;
-	(void)fd;
-	(void)events;
-
-	nameserver_send_probe(ns);
-}
-
-/* a libevent callback which is called when a nameserver probe (to see if */
-/* it has come back to life) times out. We increment the count of failed_times */
-/* and wait longer to send the next probe packet. */
-static void
-nameserver_probe_failed(struct nameserver *const ns) {
-	const struct timeval * timeout;
-	del_timeout_event(ns);
-
-	if (ns->state == 1) {
-		/* This can happen if the nameserver acts in a way which makes us mark */
-		/* it as bad and then starts sending good replies. */
-		return;
-	}
-
-	timeout =
-		&global_nameserver_timeouts[MIN(ns->failed_times,
-										global_nameserver_timeouts_length - 1)];
-	ns->failed_times++;
-
-	if (add_timeout_event(ns, (struct timeval *) timeout) < 0) {
-		evdns_log(EVDNS_LOG_WARN,
-			"Error from libevent when adding timer event for %s",
-			debug_ntop((struct sockaddr *)&ns->address));
-		/* ???? Do more? */
-	}
-}
-
-/* called when a nameserver has been deemed to have failed. For example, too */
-/* many packets have timed out etc */
-static void
-nameserver_failed(struct nameserver *const ns, const char *msg) {
-	struct evdns_request *req, *started_at;
-	/* if this nameserver has already been marked as failed */
-	/* then don't do anything */
-	if (!ns->state) return;
-
-	evdns_log(EVDNS_LOG_WARN, "Nameserver %s has failed: %s",
-		debug_ntop((struct sockaddr *)&ns->address), msg);
-	global_good_nameservers--;
-	assert(global_good_nameservers >= 0);
-	if (global_good_nameservers == 0) {
-		evdns_log(EVDNS_LOG_WARN, "All nameservers have failed");
-	}
-
-	ns->state = 0;
-	ns->failed_times = 1;
-
-	if (add_timeout_event(ns, (struct timeval *) &global_nameserver_timeouts[0]) < 0) {
-		evdns_log(EVDNS_LOG_WARN,
-			"Error from libevent when adding timer event for %s",
-			debug_ntop((struct sockaddr *)&ns->address));
-		/* ???? Do more? */
-	}
-
-	/* walk the list of inflight requests to see if any can be reassigned to */
-	/* a different server. Requests in the waiting queue don't have a */
-	/* nameserver assigned yet */
-
-	/* if we don't have *any* good nameservers then there's no point */
-	/* trying to reassign requests to one */
-	if (!global_good_nameservers) return;
-
-	req = req_head;
-	started_at = req_head;
-	if (req) {
-		do {
-			if (req->tx_count == 0 && req->ns == ns) {
-				/* still waiting to go out, can be moved */
-				/* to another server */
-				req->ns = nameserver_pick();
-			}
-			req = req->next;
-		} while (req != started_at);
-	}
-}
-
-static void
-nameserver_up(struct nameserver *const ns) {
-	if (ns->state) return;
-	evdns_log(EVDNS_LOG_WARN, "Nameserver %s is back up",
-		debug_ntop((struct sockaddr *)&ns->address));
-	del_timeout_event(ns);
-	ns->state = 1;
-	ns->failed_times = 0;
-	ns->timedout = 0;
-	global_good_nameservers++;
-}
-
-static void
-request_trans_id_set(struct evdns_request *const req, const u16 trans_id) {
-	req->trans_id = trans_id;
-	*((u16 *) req->request) = htons(trans_id);
-}
-
-/* Called to remove a request from a list and dealloc it. */
-/* head is a pointer to the head of the list it should be */
-/* removed from or NULL if the request isn't in a list. */
-static void
-request_finished(struct evdns_request *const req, struct evdns_request **head) {
-	if (head) {
-		if (req->next == req) {
-			/* only item in the list */
-			*head = NULL;
-		} else {
-			req->next->prev = req->prev;
-			req->prev->next = req->next;
-			if (*head == req) *head = req->next;
-		}
-	}
-
-	evdns_log(EVDNS_LOG_DEBUG, "Removing timeout for request %lx",
-		(unsigned long) req);
-	del_timeout_event(req);
-
-	search_request_finished(req);
-	global_requests_inflight--;
-
-	if (!req->request_appended) {
-		/* need to free the request data on it's own */
-		mm_free(req->request);
-	} else {
-		/* the request data is appended onto the header */
-		/* so everything gets mm_free()ed when we: */
-	}
-
-	CLEAR(req);
-	_mm_free(req);
-
-	evdns_requests_pump_waiting_queue();
-}
-
-/* This is called when a server returns a funny error code. */
-/* We try the request again with another server. */
-/* */
-/* return: */
-/* 0 ok */
-/* 1 failed/reissue is pointless */
-static int
-request_reissue(struct evdns_request *req) {
-	const struct nameserver *const last_ns = req->ns;
-	/* the last nameserver should have been marked as failing */
-	/* by the caller of this function, therefore pick will try */
-	/* not to return it */
-	req->ns = nameserver_pick();
-	if (req->ns == last_ns) {
-		/* ... but pick did return it */
-		/* not a lot of point in trying again with the */
-		/* same server */
-		return 1;
-	}
-
-	req->reissue_count++;
-	req->tx_count = 0;
-	req->transmit_me = 1;
-
-	return 0;
-}
-
-/* this function looks for space on the inflight queue and promotes */
-/* requests from the waiting queue if it can. */
-static void
-evdns_requests_pump_waiting_queue(void) {
-	while (global_requests_inflight < global_max_requests_inflight &&
-		global_requests_waiting) {
-		struct evdns_request *req;
-		/* move a request from the waiting queue to the inflight queue */
-		assert(req_waiting_head);
-		if (req_waiting_head->next == req_waiting_head) {
-			/* only one item in the queue */
-			req = req_waiting_head;
-			req_waiting_head = NULL;
-		} else {
-			req = req_waiting_head;
-			req->next->prev = req->prev;
-			req->prev->next = req->next;
-			req_waiting_head = req->next;
-		}
-
-		global_requests_waiting--;
-		global_requests_inflight++;
-
-		req->ns = nameserver_pick();
-		request_trans_id_set(req, transaction_id_pick());
-
-		evdns_request_insert(req, &req_head);
-		evdns_request_transmit(req);
-		evdns_transmit();
-	}
-}
-
-static void
-reply_callback(struct evdns_request *const req, u32 ttl, u32 err, struct reply *reply) {
-	switch (req->request_type) {
-	case TYPE_A:
-		if (reply)
-			req->user_callback(DNS_ERR_NONE, DNS_IPv4_A,
-							   reply->data.a.addrcount, ttl,
-							   reply->data.a.addresses,
-							   req->user_pointer);
-		else
-			req->user_callback(err, 0, 0, 0, NULL, req->user_pointer);
-		return;
-	case TYPE_PTR:
-		if (reply) {
-			char *name = reply->data.ptr.name;
-			req->user_callback(DNS_ERR_NONE, DNS_PTR, 1, ttl,
-							   &name, req->user_pointer);
-		} else {
-			req->user_callback(err, 0, 0, 0, NULL,
-							   req->user_pointer);
-		}
-		return;
-	case TYPE_AAAA:
-		if (reply)
-			req->user_callback(DNS_ERR_NONE, DNS_IPv6_AAAA,
-							   reply->data.aaaa.addrcount, ttl,
-							   reply->data.aaaa.addresses,
-							   req->user_pointer);
-		else
-			req->user_callback(err, 0, 0, 0, NULL, req->user_pointer);
-		return;
-	}
-	assert(0);
-}
-
-/* this processes a parsed reply packet */
-static void
-reply_handle(struct evdns_request *const req, u16 flags, u32 ttl, struct reply *reply) {
-	int error;
-	static const int error_codes[] = {DNS_ERR_FORMAT, DNS_ERR_SERVERFAILED, DNS_ERR_NOTEXIST, DNS_ERR_NOTIMPL, DNS_ERR_REFUSED};
-
-	if (flags & 0x020f || !reply || !reply->have_answer) {
-		/* there was an error */
-		if (flags & 0x0200) {
-			error = DNS_ERR_TRUNCATED;
-		} else {
-			u16 error_code = (flags & 0x000f) - 1;
-			if (error_code > 4) {
-				error = DNS_ERR_UNKNOWN;
-			} else {
-				error = error_codes[error_code];
-			}
-		}
-
-		switch(error) {
-		case DNS_ERR_NOTIMPL:
-		case DNS_ERR_REFUSED:
-			/* we regard these errors as marking a bad nameserver */
-			if (req->reissue_count < global_max_reissues) {
-				char msg[64];
-				tor_snprintf(msg, sizeof(msg), "Bad response %d (%s)",
-						 error, evdns_err_to_string(error));
-				nameserver_failed(req->ns, msg);
-				if (!request_reissue(req)) return;
-			}
-			break;
-		case DNS_ERR_SERVERFAILED:
-			/* rcode 2 (servfailed) sometimes means "we are broken" and
-			 * sometimes (with some binds) means "that request was very
-			 * confusing."  Treat this as a timeout, not a failure.
-			 */
-			/*XXXX refactor the parts of */
-			evdns_log(EVDNS_LOG_DEBUG, "Got a SERVERFAILED from nameserver %s; "
-				"will allow the request to time out.",
-				debug_ntop((struct sockaddr *)&req->ns->address));
-			break;
-		default:
-			/* we got a good reply from the nameserver */
-			nameserver_up(req->ns);
-		}
-
-		if (req->search_state && req->request_type != TYPE_PTR) {
-			/* if we have a list of domains to search in, try the next one */
-			if (!search_try_next(req)) {
-				/* a new request was issued so this request is finished and */
-				/* the user callback will be made when that request (or a */
-				/* child of it) finishes. */
-				request_finished(req, &req_head);
-				return;
-			}
-		}
-
-		/* all else failed. Pass the failure up */
-		reply_callback(req, 0, error, NULL);
-		request_finished(req, &req_head);
-	} else {
-		/* all ok, tell the user */
-		reply_callback(req, ttl, 0, reply);
-		nameserver_up(req->ns);
-		request_finished(req, &req_head);
-	}
-}
-
-static inline int
-name_parse(u8 *packet, int length, int *idx, char *name_out, size_t name_out_len) {
-	int name_end = -1;
-	int j = *idx;
-	int ptr_count = 0;
-#define GET32(x) do { if (j + 4 > length) goto err; memcpy(&_t32, packet + j, 4); j += 4; x = ntohl(_t32); } while(0)
-#define GET16(x) do { if (j + 2 > length) goto err; memcpy(&_t, packet + j, 2); j += 2; x = ntohs(_t); } while(0)
-#define GET8(x) do { if (j >= length) goto err; x = packet[j++]; } while(0)
-
-	char *cp = name_out;
-	const char *const end = name_out + name_out_len;
-
-	/* Normally, names are a series of length prefixed strings terminated */
-	/* with a length of 0 (the lengths are u8's < 63). */
-	/* However, the length can start with a pair of 1 bits and that */
-	/* means that the next 14 bits are a pointer within the current */
-	/* packet. */
-
-	for(;;) {
-		u8 label_len;
-		if (j >= length) return -1;
-		GET8(label_len);
-		if (!label_len) break;
-		if (label_len & 0xc0) {
-			u8 ptr_low;
-			GET8(ptr_low);
-			if (name_end < 0) name_end = j;
-			j = (((int)label_len & 0x3f) << 8) + ptr_low;
-			/* Make sure that the target offset is in-bounds. */
-			if (j < 0 || j >= length) return -1;
-			/* If we've jumped more times than there are characters in the
-			 * message, we must have a loop. */
-			if (++ptr_count > length) return -1;
-			continue;
-		}
-		if (label_len > 63) return -1;
-		if (cp != name_out) {
-			if (cp >= name_out + name_out_len - 1) return -1;
-			*cp++ = '.';
-		}
-		if (label_len > name_out_len ||
-			cp >= name_out + name_out_len - label_len) return -1;
-		memcpy(cp, packet + j, label_len);
-		cp += label_len;
-		j += label_len;
-	}
-	if (cp >= end) return -1;
-	*cp = '\0';
-	if (name_end < 0)
-		*idx = j;
-	else
-		*idx = name_end;
-	return 0;
- err:
-	return -1;
-}
-
-/* parses a raw reply from a nameserver. */
-static int
-reply_parse(u8 *packet, int length) {
-	int j = 0;	/* index into packet */
-	int k;
-	u16 _t;	 /* used by the macros */
-	u32 _t32;  /* used by the macros */
-	char tmp_name[256], cmp_name[256]; /* used by the macros */
-
-	u16 trans_id, questions, answers, authority, additional, datalength;
-	u16 flags = 0;
-	u32 ttl, ttl_r = 0xffffffff;
-	struct reply reply;
-	struct evdns_request *req = NULL;
-	unsigned int i;
-	int name_matches = 0;
-
-	GET16(trans_id);
-	GET16(flags);
-	GET16(questions);
-	GET16(answers);
-	GET16(authority);
-	GET16(additional);
-	(void) authority; /* suppress "unused variable" warnings. */
-	(void) additional; /* suppress "unused variable" warnings. */
-
-	req = request_find_from_trans_id(trans_id);
-	/* if no request, can't do anything. */
-	if (!req) return -1;
-
-	memset(&reply, 0, sizeof(reply));
-
-	/* If it's not an answer, it doesn't go with any of our requests. */
-	if (!(flags & 0x8000)) return -1;  /* must be an answer */
-	if (flags & 0x020f) {
-		/* there was an error */
-		goto err;
-	}
-	/* if (!answers) return; */  /* must have an answer of some form */
-
-	/* This macro skips a name in the DNS reply. */
-#define GET_NAME \
-	do { tmp_name[0] = '\0';				\
-		if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
-			goto err;				\
-	} while(0)
-#define TEST_NAME \
-	do { tmp_name[0] = '\0';				\
-		cmp_name[0] = '\0';				\
-		k = j;						\
-		if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
-			goto err;					\
-		if (name_parse(req->request, req->request_len, &k, cmp_name, sizeof(cmp_name))<0)	\
-			goto err;				\
-		if (global_randomize_case) {							\
-			if (strcmp(tmp_name, cmp_name) == 0)				\
-				name_matches = 1; /* we ignore mismatching names */	\
-		} else {													\
-			if (strcasecmp(tmp_name, cmp_name) == 0)				\
-				name_matches = 1;									\
-		}															\
-	} while(0)
-
-	reply.type = req->request_type;
-
-	/* skip over each question in the reply */
-	for (i = 0; i < questions; ++i) {
-		/* the question looks like
-		 * <label:name><u16:type><u16:class>
-		 */
-		TEST_NAME;
-		j += 4;
-		if (j >= length) goto err;
-	}
-
-	if (!name_matches)
-		goto err;
-
-	/* now we have the answer section which looks like
-	 * <label:name><u16:type><u16:class><u32:ttl><u16:len><data...>
-	 */
-
-	for (i = 0; i < answers; ++i) {
-		u16 type, class;
-
-		GET_NAME;
-		GET16(type);
-		GET16(class);
-		GET32(ttl);
-		GET16(datalength);
-
-		if (type == TYPE_A && class == CLASS_INET) {
-			int addrcount, addrtocopy;
-			if (req->request_type != TYPE_A) {
-				j += datalength; continue;
-			}
-			if ((datalength & 3) != 0) /* not an even number of As. */
-				goto err;
-			addrcount = datalength >> 2;
-			addrtocopy = MIN(MAX_ADDRS - reply.data.a.addrcount, (unsigned)addrcount);
-
-			ttl_r = MIN(ttl_r, ttl);
-			/* we only bother with the first four addresses. */
-			if (j + 4*addrtocopy > length) goto err;
-			memcpy(&reply.data.a.addresses[reply.data.a.addrcount],
-				   packet + j, 4*addrtocopy);
-			reply.data.a.addrcount += addrtocopy;
-			reply.have_answer = 1;
-			if (reply.data.a.addrcount == MAX_ADDRS) break;
-			j += 4*addrtocopy;
-		} else if (type == TYPE_PTR && class == CLASS_INET) {
-			if (req->request_type != TYPE_PTR) {
-				j += datalength; continue;
-			}
-			GET_NAME;
-			strlcpy(reply.data.ptr.name, tmp_name,
-					sizeof(reply.data.ptr.name));
-			ttl_r = MIN(ttl_r, ttl);
-			reply.have_answer = 1;
-			break;
-		} else if (type == TYPE_AAAA && class == CLASS_INET) {
-			int addrcount, addrtocopy;
-			if (req->request_type != TYPE_AAAA) {
-				j += datalength; continue;
-			}
-			if ((datalength & 15) != 0) /* not an even number of AAAAs. */
-				goto err;
-			addrcount = datalength >> 4;  /* each address is 16 bytes long */
-			addrtocopy = MIN(MAX_ADDRS - reply.data.aaaa.addrcount, (unsigned)addrcount);
-			ttl_r = MIN(ttl_r, ttl);
-
-			/* we only bother with the first four addresses. */
-			if (j + 16*addrtocopy > length) goto err;
-			memcpy(&reply.data.aaaa.addresses[reply.data.aaaa.addrcount],
-				   packet + j, 16*addrtocopy);
-			reply.data.aaaa.addrcount += addrtocopy;
-			reply.have_answer = 1;
-			if (reply.data.aaaa.addrcount == MAX_ADDRS) break;
-			j += 16*addrtocopy;
-		} else {
-			/* skip over any other type of resource */
-			j += datalength;
-		}
-	}
-
-	reply_handle(req, flags, ttl_r, &reply);
-	return 0;
- err:
-	if (req)
-		reply_handle(req, flags, 0, NULL);
-	return -1;
-}
-
-/* Parse a raw request (packet,length) sent to a nameserver port (port) from */
-/* a DNS client (addr,addrlen), and if it's well-formed, call the corresponding */
-/* callback. */
-static int
-request_parse(u8 *packet, ssize_t length, struct evdns_server_port *port, struct sockaddr *addr, socklen_t addrlen)
-{
-	int j = 0;	/* index into packet */
-	u16 _t;	 /* used by the macros */
-	char tmp_name[256]; /* used by the macros */
-
-	int i;
-	u16 trans_id, flags, questions, answers, authority, additional;
-	struct server_request *server_req = NULL;
-
-	/* Get the header fields */
-	GET16(trans_id);
-	GET16(flags);
-	GET16(questions);
-	GET16(answers);
-	GET16(authority);
-	GET16(additional);
-	(void)additional;
-	(void)authority;
-	(void)answers;
-
-	if (flags & 0x8000) return -1; /* Must not be an answer. */
-	flags &= 0x0110; /* Only RD and CD get preserved. */
-
-    if (length > INT_MAX)
-        return -1;
-
-	server_req = mm_malloc(sizeof(struct server_request));
-	if (server_req == NULL) return -1;
-	memset(server_req, 0, sizeof(struct server_request));
-
-	server_req->trans_id = trans_id;
-	memcpy(&server_req->addr, addr, addrlen);
-	server_req->addrlen = addrlen;
-
-	server_req->base.flags = flags;
-	server_req->base.nquestions = 0;
-	server_req->base.questions = mm_malloc(sizeof(struct evdns_server_question *) * questions);
-	if (server_req->base.questions == NULL)
-		goto err;
-
-	for (i = 0; i < questions; ++i) {
-		u16 type, class;
-		struct evdns_server_question *q;
-		size_t namelen;
-		if (name_parse(packet, (int)length, &j, tmp_name, sizeof(tmp_name))<0)
-			goto err;
-		GET16(type);
-		GET16(class);
-		namelen = strlen(tmp_name);
-		q = mm_malloc(sizeof(struct evdns_server_question) + namelen);
-		if (!q)
-			goto err;
-		q->type = type;
-		q->dns_question_class = class;
-		memcpy(q->name, tmp_name, namelen+1);
-		server_req->base.questions[server_req->base.nquestions++] = q;
-	}
-
-	/* Ignore answers, authority, and additional. */
-
-	server_req->port = port;
-	port->refcnt++;
-
-	/* Only standard queries are supported. */
-	if (flags & 0x7800) {
-		evdns_server_request_respond(&(server_req->base), DNS_ERR_NOTIMPL);
-		return -1;
-	}
-
-	port->user_callback(&(server_req->base), port->user_data);
-
-	return 0;
-err:
-	if (server_req) {
-		if (server_req->base.questions) {
-			for (i = 0; i < server_req->base.nquestions; ++i)
-				mm_free(server_req->base.questions[i]);
-			mm_free(server_req->base.questions);
-		}
-		CLEAR(server_req);
-		mm_free(server_req);
-	}
-	return -1;
-
-#undef SKIP_NAME
-#undef GET32
-#undef GET16
-#undef GET8
-}
-
-static uint16_t
-default_transaction_id_fn(void)
-{
-	u16 trans_id;
-#ifdef DNS_USE_CPU_CLOCK_FOR_ID
-	struct timespec ts;
-#ifdef CLOCK_MONOTONIC
-	if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1)
-#else
-	if (clock_gettime(CLOCK_REALTIME, &ts) == -1)
-#endif
-	event_err(1, "clock_gettime");
-	trans_id = ts.tv_nsec & 0xffff;
-#endif
-
-#ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
-	struct timeval tv;
-	gettimeofday(&tv, NULL);
-	trans_id = tv.tv_usec & 0xffff;
-#endif
-
-#ifdef DNS_USE_OPENSSL_FOR_ID
-	if (RAND_pseudo_bytes((u8 *) &trans_id, 2) == -1) {
-		/* in the case that the RAND call fails we back */
-		/* down to using gettimeofday. */
-		/*
-		  struct timeval tv;
-		  gettimeofday(&tv, NULL);
-		  trans_id = tv.tv_usec & 0xffff;
-		*/
-		abort();
-	}
-#endif
-	return (unsigned short) trans_id;
-}
-
-static uint16_t (*trans_id_function)(void) = default_transaction_id_fn;
-
-static void
-default_random_bytes_fn(char *buf, size_t n)
-{
-	unsigned i;
-	for (i = 0; i < n; i += 2) {
-		u16 tid = trans_id_function();
-		buf[i] = (tid >> 8) & 0xff;
-		if (i+1<n)
-			buf[i+1] = tid & 0xff;
-	}
-}
-
-static void (*rand_bytes_function)(char *buf, size_t n) =
-	default_random_bytes_fn;
-
-static u16
-trans_id_from_random_bytes_fn(void)
-{
-	u16 tid;
-	rand_bytes_function((char*) &tid, sizeof(tid));
-	return tid;
-}
-
-void
-evdns_set_transaction_id_fn(uint16_t (*fn)(void))
-{
-	if (fn)
-		trans_id_function = fn;
-	else
-		trans_id_function = default_transaction_id_fn;
-	rand_bytes_function = default_random_bytes_fn;
-}
-
-void
-evdns_set_random_bytes_fn(void (*fn)(char *, size_t))
-{
-	rand_bytes_function = fn;
-	trans_id_function = trans_id_from_random_bytes_fn;
-}
-
-/* Try to choose a strong transaction id which isn't already in flight */
-static u16
-transaction_id_pick(void) {
-	for (;;) {
-		const struct evdns_request *req = req_head, *started_at;
-		u16 trans_id = trans_id_function();
-
-		if (trans_id == 0xffff) continue;
-		/* now check to see if that id is already inflight */
-		req = started_at = req_head;
-		if (req) {
-			do {
-				if (req->trans_id == trans_id) break;
-				req = req->next;
-			} while (req != started_at);
-		}
-		/* we didn't find it, so this is a good id */
-		if (req == started_at) return trans_id;
-	}
-}
-
-/* choose a namesever to use. This function will try to ignore */
-/* nameservers which we think are down and load balance across the rest */
-/* by updating the server_head global each time. */
-static struct nameserver *
-nameserver_pick(void) {
-	struct nameserver *started_at = server_head, *picked;
-	if (!server_head) return NULL;
-
-	/* if we don't have any good nameservers then there's no */
-	/* point in trying to find one. */
-	if (!global_good_nameservers) {
-		server_head = server_head->next;
-		return server_head;
-	}
-
-	/* remember that nameservers are in a circular list */
-	for (;;) {
-		if (server_head->state) {
-			/* we think this server is currently good */
-			picked = server_head;
-			server_head = server_head->next;
-			return picked;
-		}
-
-		server_head = server_head->next;
-		if (server_head == started_at) {
-			/* all the nameservers seem to be down */
-			/* so we just return this one and hope for the */
-			/* best */
-			assert(global_good_nameservers == 0);
-			picked = server_head;
-			server_head = server_head->next;
-			return picked;
-		}
-	}
-}
-
-/* this is called when a namesever socket is ready for reading */
-static void
-nameserver_read(struct nameserver *ns) {
-	struct sockaddr_storage ss;
-	struct sockaddr *sa = (struct sockaddr *) &ss;
-	socklen_t addrlen = sizeof(ss);
-	u8 packet[1500];
-
-	for (;;) {
-		const int r =
-            (int)recvfrom(ns->socket, (void*)packet,
-						  (socklen_t)sizeof(packet), 0,
-						  sa, &addrlen);
-		if (r < 0) {
-			int err = last_error(ns->socket);
-			if (error_is_eagain(err)) return;
-			nameserver_failed(ns, tor_socket_strerror(err));
-			return;
-		}
-		/* XXX Match port too? */
-		if (!sockaddr_eq(sa, (struct sockaddr*)&ns->address, 0)) {
-			evdns_log(EVDNS_LOG_WARN,
-				"Address mismatch on received DNS packet.  Address was %s",
-				debug_ntop(sa));
-			return;
-		}
-		ns->timedout = 0;
-		reply_parse(packet, r);
-	}
-}
-
-/* Read a packet from a DNS client on a server port s, parse it, and */
-/* act accordingly. */
-static void
-server_port_read(struct evdns_server_port *s) {
-	u8 packet[1500];
-	struct sockaddr_storage addr;
-	socklen_t addrlen;
-	ssize_t r;
-
-	for (;;) {
-		addrlen = (socklen_t)sizeof(struct sockaddr_storage);
-		r = recvfrom(s->socket, (void*)packet, sizeof(packet), 0,
-					 (struct sockaddr*) &addr, &addrlen);
-		if (r < 0) {
-			int err = last_error(s->socket);
-			if (error_is_eagain(err)) return;
-			evdns_log(EVDNS_LOG_WARN, "Error %s (%d) while reading request.",
-				tor_socket_strerror(err), err);
-			return;
-		}
-		request_parse(packet, r, s, (struct sockaddr*) &addr, addrlen);
-	}
-}
-
-/* Try to write all pending replies on a given DNS server port. */
-static void
-server_port_flush(struct evdns_server_port *port)
-{
-	struct server_request *req = port->pending_replies;
-	while (req) {
-		ssize_t r = sendto(port->socket, req->response, req->response_len, 0,
-                       (struct sockaddr*) &req->addr, (socklen_t)req->addrlen);
-		if (r < 0) {
-			int err = last_error(port->socket);
-			if (error_is_eagain(err))
-				return;
-			evdns_log(EVDNS_LOG_WARN, "Error %s (%d) while writing response to port; dropping", tor_socket_strerror(err), err);
-		}
-		if (server_request_free(req)) {
-			/* we released the last reference to req->port. */
-			return;
-		} else {
-			assert(port->pending_replies != req);
-			req = port->pending_replies;
-		}
-	}
-
-	/* We have no more pending requests; stop listening for 'writeable' events. */
-	(void) event_del(&port->event);
-	CLEAR(&port->event);
-	event_set(&port->event, port->socket, EV_READ | EV_PERSIST,
-			  server_port_ready_callback, port);
-	if (event_add(&port->event, NULL) < 0) {
-		evdns_log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server.");
-		/* ???? Do more? */
-	}
-}
-
-/* set if we are waiting for the ability to write to this server. */
-/* if waiting is true then we ask libevent for EV_WRITE events, otherwise */
-/* we stop these events. */
-static void
-nameserver_write_waiting(struct nameserver *ns, char waiting) {
-	if (ns->write_waiting == waiting) return;
-
-	ns->write_waiting = waiting;
-	(void) event_del(&ns->event);
-	CLEAR(&ns->event);
-	event_set(&ns->event, ns->socket, EV_READ | (waiting ? EV_WRITE : 0) | EV_PERSIST,
-			  nameserver_ready_callback, ns);
-	if (event_add(&ns->event, NULL) < 0) {
-		evdns_log(EVDNS_LOG_WARN, "Error from libevent when adding event for %s",
-			debug_ntop((struct sockaddr *)&ns->address));
-		/* ???? Do more? */
-	}
-}
-
-/* a callback function. Called by libevent when the kernel says that */
-/* a nameserver socket is ready for writing or reading */
-static void
-nameserver_ready_callback(int fd, short events, void *arg) {
-	struct nameserver *ns = (struct nameserver *) arg;
-	(void)fd;
-
-	if (events & EV_WRITE) {
-		ns->choked = 0;
-		if (!evdns_transmit()) {
-			nameserver_write_waiting(ns, 0);
-		}
-	}
-	if (events & EV_READ) {
-		nameserver_read(ns);
-	}
-}
-
-/* a callback function. Called by libevent when the kernel says that */
-/* a server socket is ready for writing or reading. */
-static void
-server_port_ready_callback(int fd, short events, void *arg) {
-	struct evdns_server_port *port = (struct evdns_server_port *) arg;
-	(void) fd;
-
-	if (events & EV_WRITE) {
-		port->choked = 0;
-		server_port_flush(port);
-	}
-	if (events & EV_READ) {
-		server_port_read(port);
-	}
-}
-
-/* This is an inefficient representation; only use it via the dnslabel_table_*
- * functions, so that is can be safely replaced with something smarter later. */
-#define MAX_LABELS 128
-/* Structures used to implement name compression */
-struct dnslabel_entry { char *v; off_t pos; };
-struct dnslabel_table {
-	int n_labels; /* number of current entries */
-	/* map from name to position in message */
-	struct dnslabel_entry labels[MAX_LABELS];
-};
-
-/* Initialize dnslabel_table. */
-static void
-dnslabel_table_init(struct dnslabel_table *table)
-{
-	table->n_labels = 0;
-}
-
-/* Free all storage held by table, but not the table itself. */
-static void
-dnslabel_clear(struct dnslabel_table *table)
-{
-	int i;
-	for (i = 0; i < table->n_labels; ++i)
-		mm_free(table->labels[i].v);
-	table->n_labels = 0;
-}
-
-/* return the position of the label in the current message, or -1 if the label */
-/* hasn't been used yet. */
-static int
-dnslabel_table_get_pos(const struct dnslabel_table *table, const char *label)
-{
-	int i;
-	for (i = 0; i < table->n_labels; ++i) {
-		if (!strcmp(label, table->labels[i].v)) {
-			off_t pos = table->labels[i].pos;
-            if (pos > 65535)
-                return -1;
-            return (int)pos;
-        }
-	}
-	return -1;
-}
-
-/* remember that we've used the label at position pos */
-static int
-dnslabel_table_add(struct dnslabel_table *table, const char *label, off_t pos)
-{
-	char *v;
-	int p;
-	if (table->n_labels == MAX_LABELS)
-		return (-1);
-	v = mm_strdup(label);
-	if (v == NULL)
-		return (-1);
-	p = table->n_labels++;
-	table->labels[p].v = v;
-	table->labels[p].pos = pos;
-
-	return (0);
-}
-
-/* Converts a string to a length-prefixed set of DNS labels, starting */
-/* at buf[j]. name and buf must not overlap. name_len should be the length */
-/* of name.	 table is optional, and is used for compression. */
-/* */
-/* Input: abc.def */
-/* Output: <3>abc<3>def<0> */
-/* */
-/* Returns the first index after the encoded name, or negative on error. */
-/* -1	 label was > 63 bytes */
-/* -2	 name too long to fit in buffer. */
-/* */
-static off_t
-dnsname_to_labels(u8 *const buf, size_t buf_len, off_t j,
-				  const char *name, const size_t name_len,
-				  struct dnslabel_table *table) {
-	const char *end = name + name_len;
-	int ref = 0;
-	u16 _t;
-
-#define APPEND16(x) do {						   \
-		if (j + 2 > (off_t)buf_len)				   \
-			goto overflow;						   \
-		_t = htons(x);							   \
-		memcpy(buf + j, &_t, 2);				   \
-		j += 2;									   \
-	} while (0)
-#define APPEND32(x) do {						   \
-		if (j + 4 > (off_t)buf_len)				   \
-			goto overflow;						   \
-		_t32 = htonl(x);						   \
-		memcpy(buf + j, &_t32, 4);				   \
-		j += 4;									   \
-	} while (0)
-
-	if (name_len > 255) return -2;
-
-	for (;;) {
-		const char *const start = name;
-		if (table && (ref = dnslabel_table_get_pos(table, name)) >= 0) {
-			APPEND16(ref | 0xc000);
-			return j;
-		}
-		name = strchr(name, '.');
-		if (!name) {
-			const size_t label_len = end - start;
-			if (label_len > 63) return -1;
-			if ((size_t)(j+label_len+1) > buf_len) return -2;
-			if (table) dnslabel_table_add(table, start, j);
-			buf[j++] = (uint8_t)label_len;
-
-			memcpy(buf + j, start, label_len);
-			j += end - start;
-			break;
-		} else {
-			/* append length of the label. */
-			const size_t label_len = name - start;
-			if (label_len > 63) return -1;
-			if ((size_t)(j+label_len+1) > buf_len) return -2;
-			if (table) dnslabel_table_add(table, start, j);
-			buf[j++] = (uint8_t)label_len;
-
-			memcpy(buf + j, start, name - start);
-			j += name - start;
-			/* hop over the '.' */
-			name++;
-		}
-	}
-
-	/* the labels must be terminated by a 0. */
-	/* It's possible that the name ended in a . */
-	/* in which case the zero is already there */
-	if (!j || buf[j-1]) buf[j++] = 0;
-	return j;
- overflow:
-	return (-2);
-}
-
-/* Finds the length of a dns request for a DNS name of the given */
-/* length. The actual request may be smaller than the value returned */
-/* here */
-static size_t
-evdns_request_len(const size_t name_len) {
-	return 96 + /* length of the DNS standard header */
-		name_len + 2 +
-		4;	/* space for the resource type */
-}
-
-/* build a dns request packet into buf. buf should be at least as long */
-/* as evdns_request_len told you it should be. */
-/* */
-/* Returns the amount of space used. Negative on error. */
-static int
-evdns_request_data_build(const char *const name, const size_t name_len,
-						 const u16 trans_id, const u16 type, const u16 class,
-						 u8 *const buf, size_t buf_len) {
-	off_t j = 0;	/* current offset into buf */
-	u16 _t;	 /* used by the macros */
-
-	APPEND16(trans_id);
-	APPEND16(0x0100);  /* standard query, recusion needed */
-	APPEND16(1);  /* one question */
-	APPEND16(0);  /* no answers */
-	APPEND16(0);  /* no authority */
-	APPEND16(0);  /* no additional */
-
-	j = dnsname_to_labels(buf, buf_len, j, name, name_len, NULL);
-	if (j < 0) {
-		return (int)j;
-	}
-
-	APPEND16(type);
-	APPEND16(class);
-
-	return (int)j;
- overflow:
-	return (-1);
-}
-
-/* exported function */
-struct evdns_server_port *
-evdns_add_server_port(tor_socket_t socket, int is_tcp, evdns_request_callback_fn_type cb, void *user_data)
-{
-	struct evdns_server_port *port;
-	if (!(port = mm_malloc(sizeof(struct evdns_server_port))))
-		return NULL;
-	memset(port, 0, sizeof(struct evdns_server_port));
-
-	assert(!is_tcp); /* TCP sockets not yet implemented */
-	port->socket = socket;
-	port->refcnt = 1;
-	port->choked = 0;
-	port->closing = 0;
-	port->user_callback = cb;
-	port->user_data = user_data;
-	port->pending_replies = NULL;
-
-	event_set(&port->event, port->socket, EV_READ | EV_PERSIST,
-			  server_port_ready_callback, port);
-	if (event_add(&port->event, NULL)<0) {
-		mm_free(port);
-		return NULL;
-	}
-	return port;
-}
-
-/* exported function */
-void
-evdns_close_server_port(struct evdns_server_port *port)
-{
-	port->closing = 1;
-	if (--port->refcnt == 0)
-		server_port_free(port);
-}
-
-/* exported function */
-int
-evdns_server_request_add_reply(struct evdns_server_request *_req, int section, const char *name, int type, int class, int ttl, int datalen, int is_name, const char *data)
-{
-	struct server_request *req = TO_SERVER_REQUEST(_req);
-	struct server_reply_item **itemp, *item;
-	int *countp;
-
-	if (req->response) /* have we already answered? */
-		return (-1);
-
-	switch (section) {
-	case EVDNS_ANSWER_SECTION:
-		itemp = &req->answer;
-		countp = &req->n_answer;
-		break;
-	case EVDNS_AUTHORITY_SECTION:
-		itemp = &req->authority;
-		countp = &req->n_authority;
-		break;
-	case EVDNS_ADDITIONAL_SECTION:
-		itemp = &req->additional;
-		countp = &req->n_additional;
-		break;
-	default:
-		return (-1);
-	}
-	while (*itemp) {
-		itemp = &((*itemp)->next);
-	}
-	item = mm_malloc(sizeof(struct server_reply_item));
-	if (!item)
-		return -1;
-	CLEAR(item);
-	item->next = NULL;
-	if (!(item->name = mm_strdup(name))) {
-		CLEAR(item);
-		mm_free(item);
-		return -1;
-	}
-	item->type = type;
-	item->class = class;
-	item->ttl = ttl;
-	item->is_name = is_name != 0;
-	item->datalen = 0;
-	item->data = NULL;
-	if (data) {
-		if (item->is_name) {
-			if (!(item->data = mm_strdup(data))) {
-				mm_free(item->name);
-				CLEAR(item);
-				mm_free(item);
-				return -1;
-			}
-			item->datalen = (u16)-1;
-		} else {
-			if (!(item->data = mm_malloc(datalen))) {
-				mm_free(item->name);
-				CLEAR(item);
-				mm_free(item);
-				return -1;
-			}
-			item->datalen = datalen;
-			memcpy(item->data, data, datalen);
-		}
-	}
-
-	*itemp = item;
-	++(*countp);
-	return 0;
-}
-
-/* exported function */
-int
-evdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl)
-{
-	return evdns_server_request_add_reply(
-		  req, EVDNS_ANSWER_SECTION, name, TYPE_A, CLASS_INET,
-		  ttl, n*4, 0, addrs);
-}
-
-/* exported function */
-int
-evdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl)
-{
-	return evdns_server_request_add_reply(
-		  req, EVDNS_ANSWER_SECTION, name, TYPE_AAAA, CLASS_INET,
-		  ttl, n*16, 0, addrs);
-}
-
-/* exported function */
-int
-evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl)
-{
-	u32 a;
-	char buf[32];
-	assert(in || inaddr_name);
-	assert(!(in && inaddr_name));
-	if (in) {
-		a = ntohl(in->s_addr);
-		tor_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
-				(int)(u8)((a	)&0xff),
-				(int)(u8)((a>>8 )&0xff),
-				(int)(u8)((a>>16)&0xff),
-				(int)(u8)((a>>24)&0xff));
-		inaddr_name = buf;
-	}
-	return evdns_server_request_add_reply(
-		  req, EVDNS_ANSWER_SECTION, inaddr_name, TYPE_PTR, CLASS_INET,
-		  ttl, -1, 1, hostname);
-}
-
-/* exported function */
-int
-evdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl)
-{
-	return evdns_server_request_add_reply(
-		  req, EVDNS_ANSWER_SECTION, name, TYPE_CNAME, CLASS_INET,
-		  ttl, -1, 1, cname);
-}
-
-
-static int
-evdns_server_request_format_response(struct server_request *req, int err)
-{
-	unsigned char buf[1500];
-	size_t buf_len = sizeof(buf);
-	off_t j = 0, r;
-	u16 _t;
-	u32 _t32;
-	int i;
-	u16 flags;
-	struct dnslabel_table table;
-
-	if (err < 0 || err > 15) return -1;
-
-	/* Set response bit and error code; copy OPCODE and RD fields from
-	 * question; copy RA and AA if set by caller. */
-	flags = req->base.flags;
-	flags |= (0x8000 | err);
-
-	dnslabel_table_init(&table);
-	APPEND16(req->trans_id);
-	APPEND16(flags);
-	APPEND16(req->base.nquestions);
-	APPEND16(req->n_answer);
-	APPEND16(req->n_authority);
-	APPEND16(req->n_additional);
-
-	/* Add questions. */
-	for (i=0; i < req->base.nquestions; ++i) {
-		const char *s = req->base.questions[i]->name;
-		j = dnsname_to_labels(buf, buf_len, j, s, strlen(s), &table);
-		if (j < 0) {
-			dnslabel_clear(&table);
-			return (int) j;
-		}
-		APPEND16(req->base.questions[i]->type);
-		APPEND16(req->base.questions[i]->dns_question_class);
-	}
-
-	/* Add answer, authority, and additional sections. */
-	for (i=0; i<3; ++i) {
-		struct server_reply_item *item;
-		if (i==0)
-			item = req->answer;
-		else if (i==1)
-			item = req->authority;
-		else
-			item = req->additional;
-		while (item) {
-			r = dnsname_to_labels(buf, buf_len, j, item->name, strlen(item->name), &table);
-			if (r < 0)
-				goto overflow;
-			j = r;
-
-			APPEND16(item->type);
-			APPEND16(item->class);
-			APPEND32(item->ttl);
-			if (item->is_name) {
-				off_t len_idx = j, name_start;
-				j += 2;
-				name_start = j;
-				r = dnsname_to_labels(buf, buf_len, j, item->data, strlen(item->data), &table);
-				if (r < 0)
-					goto overflow;
-				j = r;
-				_t = htons( (j-name_start) );
-				memcpy(buf+len_idx, &_t, 2);
-			} else {
-				APPEND16(item->datalen);
-				if (j+item->datalen > (off_t)buf_len)
-					goto overflow;
-				memcpy(buf+j, item->data, item->datalen);
-				j += item->datalen;
-			}
-			item = item->next;
-		}
-	}
-
-	if (j > 512) {
-overflow:
-		j = 512;
-		buf[2] |= 0x02; /* set the truncated bit. */
-	}
-
-	req->response_len = (size_t)j;
-
-	if (!(req->response = mm_malloc(req->response_len))) {
-		server_request_free_answers(req);
-		dnslabel_clear(&table);
-		return (-1);
-	}
-	memcpy(req->response, buf, req->response_len);
-	server_request_free_answers(req);
-	dnslabel_clear(&table);
-	return (0);
-}
-
-/* exported function */
-int
-evdns_server_request_respond(struct evdns_server_request *_req, int err)
-{
-	struct server_request *req = TO_SERVER_REQUEST(_req);
-	struct evdns_server_port *port = req->port;
-	ssize_t r;
-	if (!req->response) {
-		if ((r = evdns_server_request_format_response(req, err))<0)
-			return (int)r;
-	}
-
-	r = sendto(port->socket, req->response, req->response_len, 0,
-			   (struct sockaddr*) &req->addr, req->addrlen);
-	if (r<0) {
-		int error = last_error(port->socket);
-		if (! error_is_eagain(error))
-			return -1;
-
-		if (port->pending_replies) {
-			req->prev_pending = port->pending_replies->prev_pending;
-			req->next_pending = port->pending_replies;
-			req->prev_pending->next_pending =
-				req->next_pending->prev_pending = req;
-		} else {
-			req->prev_pending = req->next_pending = req;
-			port->pending_replies = req;
-			port->choked = 1;
-
-			(void) event_del(&port->event);
-			CLEAR(&port->event);
-			event_set(&port->event, port->socket, (port->closing?0:EV_READ) | EV_WRITE | EV_PERSIST, server_port_ready_callback, port);
-
-			if (event_add(&port->event, NULL) < 0) {
-				evdns_log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server");
-			}
-
-		}
-
-		return 1;
-	}
-	if (server_request_free(req))
-		return 0;
-
-	if (port->pending_replies)
-		server_port_flush(port);
-
-	return 0;
-}
-
-/* Free all storage held by RRs in req. */
-static void
-server_request_free_answers(struct server_request *req)
-{
-	struct server_reply_item *victim, *next, **list;
-	int i;
-	for (i = 0; i < 3; ++i) {
-		if (i==0)
-			list = &req->answer;
-		else if (i==1)
-			list = &req->authority;
-		else
-			list = &req->additional;
-
-		victim = *list;
-		while (victim) {
-			next = victim->next;
-			mm_free(victim->name);
-			if (victim->data)
-				mm_free(victim->data);
-			mm_free(victim);
-			victim = next;
-		}
-		*list = NULL;
-	}
-}
-
-/* Free all storage held by req, and remove links to it. */
-/* return true iff we just wound up freeing the server_port. */
-static int
-server_request_free(struct server_request *req)
-{
-	int i, rc=1;
-	if (req->base.questions) {
-		for (i = 0; i < req->base.nquestions; ++i)
-			mm_free(req->base.questions[i]);
-		mm_free(req->base.questions);
-	}
-
-	if (req->port) {
-		if (req->port->pending_replies == req) {
-			if (req->next_pending && req->next_pending != req)
-				req->port->pending_replies = req->next_pending;
-			else
-				req->port->pending_replies = NULL;
-		}
-		rc = --req->port->refcnt;
-	}
-
-	if (req->response) {
-		mm_free(req->response);
-	}
-
-	server_request_free_answers(req);
-
-	if (req->next_pending && req->next_pending != req) {
-		req->next_pending->prev_pending = req->prev_pending;
-		req->prev_pending->next_pending = req->next_pending;
-	}
-
-	if (rc == 0) {
-		server_port_free(req->port);
-		CLEAR(req);
-		mm_free(req);
-		return (1);
-	}
-	CLEAR(req);
-	mm_free(req);
-	return (0);
-}
-
-/* Free all storage held by an evdns_server_port.  Only called when the
- * reference count is down to 0. */
-static void
-server_port_free(struct evdns_server_port *port)
-{
-	assert(port);
-	assert(!port->refcnt);
-	assert(!port->pending_replies);
-	if (port->socket > 0) {
-		CLOSE_SOCKET(port->socket);
-		port->socket = -1;
-	}
-	(void) event_del(&port->event);
-	CLEAR(&port->event);
-	CLEAR(port);
-	mm_free(port);
-}
-
-/* exported function */
-int
-evdns_server_request_drop(struct evdns_server_request *_req)
-{
-	struct server_request *req = TO_SERVER_REQUEST(_req);
-	server_request_free(req);
-	return 0;
-}
-
-/* exported function */
-int
-evdns_server_request_get_requesting_addr(struct evdns_server_request *_req, struct sockaddr *sa, int addr_len)
-{
-	struct server_request *req = TO_SERVER_REQUEST(_req);
-	if (addr_len < (int)req->addrlen)
-		return -1;
-	memcpy(sa, &(req->addr), req->addrlen);
-	return req->addrlen;
-}
-
-#undef APPEND16
-#undef APPEND32
-
-/* this is a libevent callback function which is called when a request */
-/* has timed out. */
-static void
-evdns_request_timeout_callback(int fd, short events, void *arg) {
-	struct evdns_request *const req = (struct evdns_request *) arg;
-	(void) fd;
-	(void) events;
-
-	evdns_log(EVDNS_LOG_DEBUG, "Request %lx timed out", (unsigned long) arg);
-
-	req->ns->timedout++;
-	if (req->ns->timedout > global_max_nameserver_timeout) {
-		req->ns->timedout = 0;
-		nameserver_failed(req->ns, "request timed out.");
-	}
-
-	if (req->tx_count >= global_max_retransmits) {
-		/* this request has failed */
-		reply_callback(req, 0, DNS_ERR_TIMEOUT, NULL);
-		request_finished(req, &req_head);
-	} else {
-		/* retransmit it */
-		/* Stop waiting for the timeout.  No need to do this in
-		 * request_finished; that one already deletes the timeout event. */
-		del_timeout_event(req);
-		evdns_request_transmit(req);
-	}
-}
-
-/* try to send a request to a given server. */
-/* */
-/* return: */
-/* 0 ok */
-/* 1 temporary failure */
-/* 2 other failure */
-static int
-evdns_request_transmit_to(struct evdns_request *req, struct nameserver *server) {
-	const ssize_t r = send(server->socket, (void*)req->request,
-                         req->request_len, 0);
-	if (r < 0) {
-		int err = last_error(server->socket);
-		if (error_is_eagain(err)) return 1;
-		nameserver_failed(req->ns, tor_socket_strerror(err));
-		return 2;
-	} else if (r != (ssize_t)req->request_len) {
-		return 1;  /* short write */
-	} else {
-		return 0;
-	}
-}
-
-/* try to send a request, updating the fields of the request */
-/* as needed */
-/* */
-/* return: */
-/* 0 ok */
-/* 1 failed */
-static int
-evdns_request_transmit(struct evdns_request *req) {
-	int retcode = 0, r;
-
-	/* if we fail to send this packet then this flag marks it */
-	/* for evdns_transmit */
-	req->transmit_me = 1;
-	if (req->trans_id == 0xffff) abort();
-
-	if (req->ns->choked) {
-		/* don't bother trying to write to a socket */
-		/* which we have had EAGAIN from */
-		return 1;
-	}
-
-	r = evdns_request_transmit_to(req, req->ns);
-	switch (r) {
-	case 1:
-		/* temp failure */
-		req->ns->choked = 1;
-		nameserver_write_waiting(req->ns, 1);
-		return 1;
-	case 2:
-		/* failed to transmit the request entirely. */
-		retcode = 1;
-		/* fall through: we'll set a timeout, which will time out,
-		 * and make us retransmit the request anyway. */
-	default:
-		/* transmitted; we need to check for timeout. */
-		evdns_log(EVDNS_LOG_DEBUG,
-			"Setting timeout for request %lx", (unsigned long) req);
-
-		if (add_timeout_event(req, &global_timeout) < 0) {
-			evdns_log(EVDNS_LOG_WARN,
-				"Error from libevent when adding timer for request %lx",
-				(unsigned long) req);
-			/* ???? Do more? */
-		}
-		req->tx_count++;
-		req->transmit_me = 0;
-		return retcode;
-	}
-}
-
-static void
-nameserver_probe_callback(int result, char type, int count, int ttl, void *addresses, void *arg) {
-	struct sockaddr *addr = arg;
-	struct nameserver *server;
-	(void) type;
-	(void) count;
-	(void) ttl;
-	(void) addresses;
-
-	for (server = server_head; server; server = server->next) {
-		if (sockaddr_eq(addr, (struct sockaddr*) &server->address, 1)) {
-			if (result == DNS_ERR_NONE || result == DNS_ERR_NOTEXIST) {
-				/* this is a good reply */
-				nameserver_up(server);
-			} else {
-				nameserver_probe_failed(server);
-			}
-		}
-		if (server->next == server_head)
-			break;
-	}
-
-	mm_free(addr);
-}
-
-static void
-nameserver_send_probe(struct nameserver *const ns) {
-	struct evdns_request *req;
-	struct sockaddr_storage *addr;
-	/* here we need to send a probe to a given nameserver */
-	/* in the hope that it is up now. */
-
-	/* We identify the nameserver by its address, in case it is removed before
-	 * our probe comes back. */
-	addr = mm_malloc(sizeof(struct sockaddr_storage));
-	memcpy(addr, &ns->address, sizeof(struct sockaddr_storage));
-
-	evdns_log(EVDNS_LOG_DEBUG, "Sending probe to %s", debug_ntop((struct sockaddr *)&ns->address));
-
-	req = request_new(TYPE_A, "www.google.com", DNS_QUERY_NO_SEARCH, nameserver_probe_callback, addr);
-	if (!req) {
-		mm_free(addr);
-		return;
-	}
-	/* we force this into the inflight queue no matter what */
-	request_trans_id_set(req, transaction_id_pick());
-	req->ns = ns;
-	request_submit(req);
-}
-
-/* returns: */
-/* 0 didn't try to transmit anything */
-/* 1 tried to transmit something */
-static int
-evdns_transmit(void) {
-	char did_try_to_transmit = 0;
-
-	if (req_head) {
-		struct evdns_request *const started_at = req_head, *req = req_head;
-		/* first transmit all the requests which are currently waiting */
-		do {
-			if (req->transmit_me) {
-				did_try_to_transmit = 1;
-				evdns_request_transmit(req);
-			}
-
-			req = req->next;
-		} while (req != started_at);
-	}
-
-	return did_try_to_transmit;
-}
-
-/* exported function */
-int
-evdns_count_nameservers(void)
-{
-	const struct nameserver *server = server_head;
-	int n = 0;
-	if (!server)
-		return 0;
-	do {
-		++n;
-		server = server->next;
-	} while (server != server_head);
-	return n;
-}
-
-/* exported function */
-int
-evdns_clear_nameservers_and_suspend(void)
-{
-	struct nameserver *server = server_head, *started_at = server_head;
-	struct evdns_request *req = req_head, *req_started_at = req_head;
-
-	if (!server)
-		return 0;
-	while (1) {
-		struct nameserver *next = server->next;
-		(void) event_del(&server->event);
-		CLEAR(&server->event);
-		del_timeout_event(server);
-		if (server->socket >= 0)
-			CLOSE_SOCKET(server->socket);
-		CLEAR(server);
-		mm_free(server);
-		if (next == started_at)
-			break;
-		server = next;
-	}
-	server_head = NULL;
-	global_good_nameservers = 0;
-
-	while (req) {
-		struct evdns_request *next = req->next;
-		req->tx_count = req->reissue_count = 0;
-		req->ns = NULL;
-		/* ???? What to do about searches? */
-		del_timeout_event(req);
-		req->trans_id = 0;
-		req->transmit_me = 0;
-
-		global_requests_waiting++;
-		evdns_request_insert(req, &req_waiting_head);
-		/* We want to insert these suspended elements at the front of
-		 * the waiting queue, since they were pending before any of
-		 * the waiting entries were added.	This is a circular list,
-		 * so we can just shift the start back by one.*/
-		req_waiting_head = req_waiting_head->prev;
-
-		if (next == req_started_at)
-			break;
-		req = next;
-	}
-	req_head = NULL;
-	global_requests_inflight = 0;
-
-	return 0;
-}
-
-static struct sockaddr_storage global_bind_address;
-static socklen_t global_bind_addrlen = 0;
-static int global_bind_addr_is_set = 0;
-void
-evdns_set_default_outgoing_bind_address(const struct sockaddr *addr,
-										socklen_t addrlen)
-{
-	memset(&global_bind_address, 0, sizeof(global_bind_address));
-	if (addr) {
-		assert(addrlen <= (socklen_t)sizeof(global_bind_address));
-		memcpy(&global_bind_address, addr, addrlen);
-		global_bind_addrlen = addrlen;
-		global_bind_addr_is_set = 1;
-	} else {
-		global_bind_addr_is_set = 0;
-	}
-}
-
-/* exported function */
-int
-evdns_resume(void)
-{
-	evdns_requests_pump_waiting_queue();
-	return 0;
-}
-
-static int
-sockaddr_is_loopback(const struct sockaddr *addr)
-{
-	static const char LOOPBACK_S6[16] =
-	    "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1";
-	if (addr->sa_family == AF_INET) {
-		struct sockaddr_in *sin = (struct sockaddr_in *)addr;
-		return (ntohl(sin->sin_addr.s_addr) & 0xff000000) == 0x7f000000;
-	} else if (addr->sa_family == AF_INET6) {
-		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)addr;
-		return fast_memeq(sin6->sin6_addr.s6_addr, LOOPBACK_S6, 16);
-	}
-	return 0;
-}
-
-static int
-_evdns_nameserver_add_impl(const struct sockaddr *address,
-						   socklen_t addrlen) {
-	/* first check to see if we already have this nameserver */
-
-	const struct nameserver *server = server_head, *const started_at = server_head;
-	struct nameserver *ns;
-
-	int err = 0;
-	if (server) {
-		do {
-			if (sockaddr_eq(address, (struct sockaddr *)&server->address, 1)) {
-				evdns_log(EVDNS_LOG_DEBUG, "Duplicate nameserver.");
-				return 3;
-			}
-			server = server->next;
-		} while (server != started_at);
-	}
-	if (addrlen > (int)sizeof(ns->address)) {
-		evdns_log(EVDNS_LOG_DEBUG, "Addrlen %d too long.", (int)addrlen);
-		return 2;
-	}
-
-	ns = (struct nameserver *) mm_malloc(sizeof(struct nameserver));
-	if (!ns) return -1;
-
-	memset(ns, 0, sizeof(struct nameserver));
-
-	evtimer_set(&ns->timeout_event, nameserver_prod_callback, ns);
-
-#if 1
-	ns->socket = tor_open_socket_nonblocking(address->sa_family, SOCK_DGRAM, 0);
-	if (!SOCKET_OK(ns->socket)) { err = 1; goto out1; }
-#else
-	ns->socket = tor_open_socket(address->sa_family, SOCK_DGRAM, 0);
-	if (ns->socket < 0) { err = 1; goto out1; }
-#ifdef _WIN32
-	{
-		u_long nonblocking = 1;
-		ioctlsocket(ns->socket, FIONBIO, &nonblocking);
-	}
-#else
-	if (fcntl(ns->socket, F_SETFL, O_NONBLOCK) == -1) {
-		evdns_log(EVDNS_LOG_WARN, "Error %s (%d) while settings file status flags.",
-				  tor_socket_strerror(errno), errno);
-		err = 2;
-		goto out2;
-	}
-#endif
-
-#endif /* 1 */
-	if (global_bind_addr_is_set &&
-	    !sockaddr_is_loopback((struct sockaddr*)&global_bind_address)) {
-		if (bind(ns->socket, (struct sockaddr *)&global_bind_address,
-				 global_bind_addrlen) < 0) {
-			evdns_log(EVDNS_LOG_DEBUG, "Couldn't bind to outgoing address.");
-			err = 2;
-			goto out2;
-		}
-	}
-
-	if (connect(ns->socket, address, addrlen) != 0) {
-		evdns_log(EVDNS_LOG_DEBUG, "Couldn't open socket to nameserver.");
-		err = 2;
-		goto out2;
-	}
-
-	memcpy(&ns->address, address, addrlen);
-	ns->state = 1;
-	event_set(&ns->event, ns->socket, EV_READ | EV_PERSIST, nameserver_ready_callback, ns);
-	if (event_add(&ns->event, NULL) < 0) {
-		evdns_log(EVDNS_LOG_DEBUG, "Couldn't add event for nameserver.");
-		err = 2;
-		goto out2;
-	}
-
-	evdns_log(EVDNS_LOG_DEBUG, "Added nameserver %s", debug_ntop(address));
-
-	/* insert this nameserver into the list of them */
-	if (!server_head) {
-		ns->next = ns->prev = ns;
-		server_head = ns;
-	} else {
-		ns->next = server_head->next;
-		ns->prev = server_head;
-		server_head->next = ns;
-		if (server_head->prev == server_head) {
-			server_head->prev = ns;
-		}
-	}
-
-	global_good_nameservers++;
-
-	return 0;
-
-out2:
-	CLOSE_SOCKET(ns->socket);
-out1:
-	CLEAR(ns);
-	mm_free(ns);
-	evdns_log(EVDNS_LOG_WARN, "Unable to add nameserver %s: error %d", debug_ntop(address), err);
-	return err;
-}
-
-/* exported function */
-int
-evdns_nameserver_add(uint32_t address) {
-	struct sockaddr_in sin;
-	memset(&sin, 0, sizeof(sin));
-	sin.sin_family = AF_INET;
-#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
-	sin.sin_len = sizeof(sin);
-#endif
-	sin.sin_addr.s_addr = htonl(address);
-	sin.sin_port = 53;
-	return _evdns_nameserver_add_impl((struct sockaddr*) &sin, sizeof(sin));
-}
-
-/* exported function */
-int
-evdns_nameserver_ip_add(const char *ip_as_string) {
-	int port;
-	char buf[128];
-	const char *cp, *addr_part, *port_part;
-	int is_ipv6;
-	/* recognized formats are:
-	 * [ipv6]:port
-	 * ipv6
-	 * [ipv6]
-	 * ipv4:port
-	 * ipv4
-	 */
-
-	evdns_log(EVDNS_LOG_DEBUG, "Trying to add nameserver <%s>", ip_as_string);
-
-	cp = strchr(ip_as_string, ':');
-	if (*ip_as_string == '[') {
-		size_t len;
-		if (!(cp = strchr(ip_as_string, ']'))) {
-			evdns_log(EVDNS_LOG_DEBUG, "Nameserver missing closing ]");
-			return 4;
-		}
-		len = cp-(ip_as_string + 1);
-		if (len > sizeof(buf)-1) {
-			evdns_log(EVDNS_LOG_DEBUG, "[Nameserver] does not fit in buffer.");
-			return 4;
-		}
-		memcpy(buf, ip_as_string+1, len);
-		buf[len] = '\0';
-		addr_part = buf;
-		if (cp[1] == ':')
-			port_part = cp+2;
-		else
-			port_part = NULL;
-		is_ipv6 = 1;
-	} else if (cp && strchr(cp+1, ':')) {
-		is_ipv6 = 1;
-		addr_part = ip_as_string;
-		port_part = NULL;
-	} else if (cp) {
-		is_ipv6 = 0;
-		if (cp - ip_as_string > (int)sizeof(buf)-1) {
-			evdns_log(EVDNS_LOG_DEBUG, "Nameserver does not fit in buffer.");
-			return 4;
-		}
-		memcpy(buf, ip_as_string, cp-ip_as_string);
-		buf[cp-ip_as_string] = '\0';
-		addr_part = buf;
-		port_part = cp+1;
-	} else {
-		addr_part = ip_as_string;
-		port_part = NULL;
-		is_ipv6 = 0;
-	}
-
-	if (port_part == NULL) {
-		port = 53;
-	} else {
-		port = strtoint(port_part);
-		if (port <= 0 || port > 65535) {
-			evdns_log(EVDNS_LOG_DEBUG, "Nameserver port <%s> out of range",
-				port_part);
-			return 4;
-		}
-	}
-
-	/* Tor-only.  needs a more general fix. */
-	assert(addr_part);
-	if (is_ipv6) {
-		struct sockaddr_in6 sin6;
-		memset(&sin6, 0, sizeof(sin6));
-#ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_LEN
-		sin6.sin6_len = sizeof(sin6);
-#endif
-		sin6.sin6_family = AF_INET6;
-		sin6.sin6_port = htons(port);
-		if (1 != tor_inet_pton(AF_INET6, addr_part, &sin6.sin6_addr)) {
-			evdns_log(EVDNS_LOG_DEBUG, "inet_pton(%s) failed", addr_part);
-			return 4;
-		}
-		return _evdns_nameserver_add_impl((struct sockaddr*)&sin6,
-										  sizeof(sin6));
-	} else {
-		struct sockaddr_in sin;
-		memset(&sin, 0, sizeof(sin));
-#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
-		sin.sin_len = sizeof(sin);
-#endif
-		sin.sin_family = AF_INET;
-		sin.sin_port = htons(port);
-		if (!inet_aton(addr_part, &sin.sin_addr)) {
-			evdns_log(EVDNS_LOG_DEBUG, "inet_pton(%s) failed", addr_part);
-			return 4;
-		}
-		return _evdns_nameserver_add_impl((struct sockaddr*)&sin,
-										  sizeof(sin));
-	}
-}
-
-int
-evdns_nameserver_sockaddr_add(const struct sockaddr *sa, socklen_t len)
-{
-	return _evdns_nameserver_add_impl(sa, len);
-}
-
-/* insert into the tail of the queue */
-static void
-evdns_request_insert(struct evdns_request *req, struct evdns_request **head) {
-	if (!*head) {
-		*head = req;
-		req->next = req->prev = req;
-		return;
-	}
-
-	req->prev = (*head)->prev;
-	req->prev->next = req;
-	req->next = *head;
-	(*head)->prev = req;
-}
-
-static int
-string_num_dots(const char *s) {
-	int count = 0;
-	while ((s = strchr(s, '.'))) {
-		s++;
-		count++;
-	}
-	return count;
-}
-
-static struct evdns_request *
-request_new(int type, const char *name, int flags,
-	evdns_callback_type callback, void *user_ptr) {
-	const char issuing_now =
-		(global_requests_inflight < global_max_requests_inflight) ? 1 : 0;
-
-	const size_t name_len = strlen(name);
-	const size_t request_max_len = evdns_request_len(name_len);
-	const u16 trans_id = issuing_now ? transaction_id_pick() : 0xffff;
-	/* the request data is alloced in a single block with the header */
-	struct evdns_request *const req =
-		(struct evdns_request *) mm_malloc(sizeof(struct evdns_request) + request_max_len);
-	char namebuf[256];
-	int rlen;
-	(void) flags;
-
-	if (!req) return NULL;
-
-	if (name_len >= sizeof(namebuf)) {
-		_mm_free(req);
-		return NULL;
-	}
-
-	memset(req, 0, sizeof(struct evdns_request));
-
-	evtimer_set(&req->timeout_event, evdns_request_timeout_callback, req);
-
-	if (global_randomize_case) {
-		unsigned i;
-		char randbits[32];
-		strlcpy(namebuf, name, sizeof(namebuf));
-		rand_bytes_function(randbits, (name_len+7)/8);
-		for (i = 0; i < name_len; ++i) {
-			if (ISALPHA(namebuf[i])) {
-				if ((randbits[i >> 3] & (1<<(i%7))))
-					namebuf[i] = TOLOWER(namebuf[i]);
-				else
-					namebuf[i] = TOUPPER(namebuf[i]);
-			}
-		}
-		name = namebuf;
-	}
-
-	/* request data lives just after the header */
-	req->request = ((u8 *) req) + sizeof(struct evdns_request);
-	/* denotes that the request data shouldn't be mm_free()ed */
-	req->request_appended = 1;
-	rlen = evdns_request_data_build(name, name_len, trans_id,
-							type, CLASS_INET, req->request, request_max_len);
-	if (rlen < 0)
-		goto err1;
-	req->request_len = rlen;
-	req->trans_id = trans_id;
-	req->tx_count = 0;
-	req->request_type = type;
-	req->user_pointer = user_ptr;
-	req->user_callback = callback;
-	req->ns = issuing_now ? nameserver_pick() : NULL;
-	req->next = req->prev = NULL;
-
-	return req;
-err1:
-	CLEAR(req);
-	_mm_free(req);
-	return NULL;
-}
-
-static void
-request_submit(struct evdns_request *const req) {
-	if (req->ns) {
-		/* if it has a nameserver assigned then this is going */
-		/* straight into the inflight queue */
-		evdns_request_insert(req, &req_head);
-		global_requests_inflight++;
-		evdns_request_transmit(req);
-	} else {
-		evdns_request_insert(req, &req_waiting_head);
-		global_requests_waiting++;
-	}
-}
-
-/* exported function */
-int evdns_resolve_ipv4(const char *name, int flags,
-					   evdns_callback_type callback, void *ptr) {
-	evdns_log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
-	if (flags & DNS_QUERY_NO_SEARCH) {
-		struct evdns_request *const req =
-			request_new(TYPE_A, name, flags, callback, ptr);
-		if (req == NULL)
-			return (1);
-		request_submit(req);
-		return (0);
-	} else {
-		return (search_request_new(TYPE_A, name, flags, callback, ptr));
-	}
-}
-
-/* exported function */
-int evdns_resolve_ipv6(const char *name, int flags,
-					   evdns_callback_type callback, void *ptr) {
-	evdns_log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
-	if (flags & DNS_QUERY_NO_SEARCH) {
-		struct evdns_request *const req =
-			request_new(TYPE_AAAA, name, flags, callback, ptr);
-		if (req == NULL)
-			return (1);
-		request_submit(req);
-		return (0);
-	} else {
-		return (search_request_new(TYPE_AAAA, name, flags, callback, ptr));
-	}
-}
-
-int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
-	char buf[32];
-	struct evdns_request *req;
-	u32 a;
-	assert(in);
-	a = ntohl(in->s_addr);
-	tor_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
-			(int)(u8)((a	)&0xff),
-			(int)(u8)((a>>8 )&0xff),
-			(int)(u8)((a>>16)&0xff),
-			(int)(u8)((a>>24)&0xff));
-	evdns_log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
-	req = request_new(TYPE_PTR, buf, flags, callback, ptr);
-	if (!req) return 1;
-	request_submit(req);
-	return 0;
-}
-
-int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
-	/* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
-	char buf[73];
-	char *cp;
-	struct evdns_request *req;
-	int i;
-	assert(in);
-	cp = buf;
-	for (i=15; i >= 0; --i) {
-		u8 byte = in->s6_addr[i];
-		*cp++ = "0123456789abcdef"[byte & 0x0f];
-		*cp++ = '.';
-		*cp++ = "0123456789abcdef"[byte >> 4];
-		*cp++ = '.';
-	}
-	assert(cp + strlen("ip6.arpa") < buf+sizeof(buf));
-	memcpy(cp, "ip6.arpa", strlen("ip6.arpa")+1);
-	evdns_log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
-	req = request_new(TYPE_PTR, buf, flags, callback, ptr);
-	if (!req) return 1;
-	request_submit(req);
-	return 0;
-}
-
-/*/////////////////////////////////////////////////////////////////// */
-/* Search support */
-/* */
-/* the libc resolver has support for searching a number of domains */
-/* to find a name. If nothing else then it takes the single domain */
-/* from the gethostname() call. */
-/* */
-/* It can also be configured via the domain and search options in a */
-/* resolv.conf. */
-/* */
-/* The ndots option controls how many dots it takes for the resolver */
-/* to decide that a name is non-local and so try a raw lookup first. */
-
-struct search_domain {
-	size_t len;
-	struct search_domain *next;
-	/* the text string is appended to this structure */
-};
-
-struct search_state {
-	int refcount;
-	int ndots;
-	int num_domains;
-	struct search_domain *head;
-};
-
-static struct search_state *global_search_state = NULL;
-
-static void
-search_state_decref(struct search_state *const state) {
-	if (!state) return;
-	state->refcount--;
-	if (!state->refcount) {
-		struct search_domain *next, *dom;
-		for (dom = state->head; dom; dom = next) {
-			next = dom->next;
-			CLEAR(dom);
-			_mm_free(dom);
-		}
-		CLEAR(state);
-		_mm_free(state);
-	}
-}
-
-static struct search_state *
-search_state_new(void) {
-	struct search_state *state = (struct search_state *) mm_malloc(sizeof(struct search_state));
-	if (!state) return NULL;
-	memset(state, 0, sizeof(struct search_state));
-	state->refcount = 1;
-	state->ndots = 1;
-
-	return state;
-}
-
-static void
-search_postfix_clear(void) {
-	search_state_decref(global_search_state);
-
-	global_search_state = search_state_new();
-}
-
-/* exported function */
-void
-evdns_search_clear(void) {
-	search_postfix_clear();
-}
-
-static void
-search_postfix_add(const char *domain) {
-	size_t domain_len;
-	struct search_domain *sdomain;
-	while (domain[0] == '.') domain++;
-	domain_len = strlen(domain);
-
-	if (!global_search_state) global_search_state = search_state_new();
-		if (!global_search_state) return;
-	global_search_state->num_domains++;
-
-	sdomain = (struct search_domain *) mm_malloc(sizeof(struct search_domain) + domain_len);
-		if (!sdomain) return;
-	memcpy( ((u8 *) sdomain) + sizeof(struct search_domain), domain, domain_len);
-	sdomain->next = global_search_state->head;
-	sdomain->len = domain_len;
-
-	global_search_state->head = sdomain;
-}
-
-/* reverse the order of members in the postfix list. This is needed because, */
-/* when parsing resolv.conf we push elements in the wrong order */
-static void
-search_reverse(void) {
-	struct search_domain *cur, *prev = NULL, *next;
-	cur = global_search_state->head;
-	while (cur) {
-		next = cur->next;
-		cur->next = prev;
-		prev = cur;
-		cur = next;
-	}
-
-	global_search_state->head = prev;
-}
-
-/* exported function */
-void
-evdns_search_add(const char *domain) {
-	search_postfix_add(domain);
-}
-
-/* exported function */
-void
-evdns_search_ndots_set(const int ndots) {
-	if (!global_search_state) global_search_state = search_state_new();
-		if (!global_search_state) return;
-	global_search_state->ndots = ndots;
-}
-
-static void
-search_set_from_hostname(void) {
-	char hostname[HOST_NAME_MAX + 1], *domainname;
-
-	search_postfix_clear();
-	if (gethostname(hostname, sizeof(hostname))) return;
-	domainname = strchr(hostname, '.');
-	if (!domainname) return;
-	search_postfix_add(domainname);
-}
-
-/* warning: returns malloced string */
-static char *
-search_make_new(const struct search_state *const state, int n, const char *const base_name) {
-	const size_t base_len = strlen(base_name);
-	const char need_to_append_dot = base_name[base_len - 1] == '.' ? 0 : 1;
-	struct search_domain *dom;
-
-	for (dom = state->head; dom; dom = dom->next) {
-		if (!n--) {
-			/* this is the postfix we want */
-			/* the actual postfix string is kept at the end of the structure */
-			const u8 *const postfix = ((u8 *) dom) + sizeof(struct search_domain);
-			const size_t postfix_len = dom->len;
-			char *const newname = (char *) mm_malloc(base_len + need_to_append_dot + postfix_len + 1);
-			if (!newname) return NULL;
-			memcpy(newname, base_name, base_len);
-			if (need_to_append_dot) newname[base_len] = '.';
-			memcpy(newname + base_len + need_to_append_dot, postfix, postfix_len);
-			newname[base_len + need_to_append_dot + postfix_len] = 0;
-			return newname;
-		}
-	}
-
-	/* we ran off the end of the list and still didn't find the requested string */
-	abort();
-	return NULL; /* unreachable; stops warnings in some compilers. */
-}
-
-static int
-search_request_new(int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg) {
-	assert(type == TYPE_A || type == TYPE_AAAA);
-	if ( ((flags & DNS_QUERY_NO_SEARCH) == 0) &&
-		 global_search_state &&
-		 global_search_state->num_domains) {
-		/* we have some domains to search */
-		struct evdns_request *req;
-		if (string_num_dots(name) >= global_search_state->ndots) {
-			req = request_new(type, name, flags, user_callback, user_arg);
-			if (!req) return 1;
-			req->search_index = -1;
-		} else {
-			char *const new_name = search_make_new(global_search_state, 0, name);
-						if (!new_name) return 1;
-			req = request_new(type, new_name, flags, user_callback, user_arg);
-			_mm_free(new_name);
-			if (!req) return 1;
-			req->search_index = 0;
-		}
-		req->search_origname = mm_strdup(name);
-		req->search_state = global_search_state;
-		req->search_flags = flags;
-		global_search_state->refcount++;
-		request_submit(req);
-		return 0;
-	} else {
-		struct evdns_request *const req = request_new(type, name, flags, user_callback, user_arg);
-		if (!req) return 1;
-		request_submit(req);
-		return 0;
-	}
-}
-
-/* this is called when a request has failed to find a name. We need to check */
-/* if it is part of a search and, if so, try the next name in the list */
-/* returns: */
-/* 0 another request has been submitted */
-/* 1 no more requests needed */
-static int
-search_try_next(struct evdns_request *const req) {
-	if (req->search_state) {
-		/* it is part of a search */
-		char *new_name;
-		struct evdns_request *newreq;
-		req->search_index++;
-		if (req->search_index >= req->search_state->num_domains) {
-			/* no more postfixes to try, however we may need to try */
-			/* this name without a postfix */
-			if (string_num_dots(req->search_origname) < req->search_state->ndots) {
-				/* yep, we need to try it raw */
-				struct evdns_request *const newreq = request_new(req->request_type, req->search_origname, req->search_flags, req->user_callback, req->user_pointer);
-				evdns_log(EVDNS_LOG_DEBUG, "Search: trying raw query %s", req->search_origname);
-				if (newreq) {
-					request_submit(newreq);
-					return 0;
-				}
-			}
-			return 1;
-		}
-
-		new_name = search_make_new(req->search_state, req->search_index, req->search_origname);
-				if (!new_name) return 1;
-		evdns_log(EVDNS_LOG_DEBUG, "Search: now trying %s (%d)", new_name, req->search_index);
-		newreq = request_new(req->request_type, new_name, req->search_flags, req->user_callback, req->user_pointer);
-		mm_free(new_name);
-		if (!newreq) return 1;
-		newreq->search_origname = req->search_origname;
-		req->search_origname = NULL;
-		newreq->search_state = req->search_state;
-		newreq->search_flags = req->search_flags;
-		newreq->search_index = req->search_index;
-		newreq->search_state->refcount++;
-		request_submit(newreq);
-		return 0;
-	}
-	return 1;
-}
-
-static void
-search_request_finished(struct evdns_request *const req) {
-	if (req->search_state) {
-		search_state_decref(req->search_state);
-		req->search_state = NULL;
-	}
-	if (req->search_origname) {
-		mm_free(req->search_origname);
-		req->search_origname = NULL;
-	}
-}
-
-/*/////////////////////////////////////////////////////////////////// */
-/* Parsing resolv.conf files */
-
-static void
-evdns_resolv_set_defaults(int flags) {
-	/* if the file isn't found then we assume a local resolver */
-	if (flags & DNS_OPTION_SEARCH) search_set_from_hostname();
-	if (flags & DNS_OPTION_NAMESERVERS) evdns_nameserver_ip_add("127.0.0.1");
-}
-
-/* helper version of atoi which returns -1 on error */
-static int
-strtoint(const char *const str) {
-	char *endptr;
-	const long r = strtol(str, &endptr, 10);
-	if (*endptr || r > INT_MAX) return -1;
-	return (int)r;
-}
-
-/* helper version of atoi that returns -1 on error and clips to bounds. */
-static int
-strtoint_clipped(const char *const str, int min, int max)
-{
-	int r = strtoint(str);
-	if (r == -1)
-		return r;
-	else if (r<min)
-		return min;
-	else if (r>max)
-		return max;
-	else
-		return r;
-}
-
-/* exported function */
-int
-evdns_set_option(const char *option, const char *val, int flags)
-{
-	if (!strncmp(option, "ndots:", 6)) {
-		const int ndots = strtoint(val);
-		if (ndots == -1) return -1;
-		if (!(flags & DNS_OPTION_SEARCH)) return 0;
-		evdns_log(EVDNS_LOG_DEBUG, "Setting ndots to %d", ndots);
-		if (!global_search_state) global_search_state = search_state_new();
-		if (!global_search_state) return -1;
-		global_search_state->ndots = ndots;
-	} else if (!strncmp(option, "timeout:", 8)) {
-		const int timeout = strtoint(val);
-		if (timeout == -1) return -1;
-		if (!(flags & DNS_OPTION_MISC)) return 0;
-		evdns_log(EVDNS_LOG_DEBUG, "Setting timeout to %d", timeout);
-		global_timeout.tv_sec = timeout;
-	} else if (!strncmp(option, "max-timeouts:", 12)) {
-		const int maxtimeout = strtoint_clipped(val, 1, 255);
-		if (maxtimeout == -1) return -1;
-		if (!(flags & DNS_OPTION_MISC)) return 0;
-		evdns_log(EVDNS_LOG_DEBUG, "Setting maximum allowed timeouts to %d",
-			maxtimeout);
-		global_max_nameserver_timeout = maxtimeout;
-	} else if (!strncmp(option, "max-inflight:", 13)) {
-		const int maxinflight = strtoint_clipped(val, 1, 65000);
-		if (maxinflight == -1) return -1;
-		if (!(flags & DNS_OPTION_MISC)) return 0;
-		evdns_log(EVDNS_LOG_DEBUG, "Setting maximum inflight requests to %d",
-			maxinflight);
-		global_max_requests_inflight = maxinflight;
-	} else if (!strncmp(option, "attempts:", 9)) {
-		int retries = strtoint(val);
-		if (retries == -1) return -1;
-		if (retries > 255) retries = 255;
-		if (!(flags & DNS_OPTION_MISC)) return 0;
-		evdns_log(EVDNS_LOG_DEBUG, "Setting retries to %d", retries);
-		global_max_retransmits = retries;
-	} else if (!strncmp(option, "randomize-case:", 15)) {
-		int randcase = strtoint(val);
-		if (!(flags & DNS_OPTION_MISC)) return 0;
-		evdns_log(EVDNS_LOG_DEBUG, "Setting randomize_case to %d", randcase);
-		global_randomize_case = randcase;
-	}
-	return 0;
-}
-
-static void
-resolv_conf_parse_line(char *const start, int flags) {
-	char *strtok_state;
-	static const char *const delims = " \t";
-#define NEXT_TOKEN tor_strtok_r(NULL, delims, &strtok_state)
-
-	char *const first_token = tor_strtok_r(start, delims, &strtok_state);
-	if (!first_token) return;
-
-	if (!strcmp(first_token, "nameserver") && (flags & DNS_OPTION_NAMESERVERS)) {
-		const char *const nameserver = NEXT_TOKEN;
-		if (nameserver)
-			evdns_nameserver_ip_add(nameserver);
-	} else if (!strcmp(first_token, "domain") && (flags & DNS_OPTION_SEARCH)) {
-		const char *const domain = NEXT_TOKEN;
-		if (domain) {
-			search_postfix_clear();
-			search_postfix_add(domain);
-		}
-	} else if (!strcmp(first_token, "search") && (flags & DNS_OPTION_SEARCH)) {
-		const char *domain;
-		search_postfix_clear();
-
-		while ((domain = NEXT_TOKEN)) {
-			search_postfix_add(domain);
-		}
-		search_reverse();
-	} else if (!strcmp(first_token, "options")) {
-		const char *option;
-		while ((option = NEXT_TOKEN)) {
-			const char *val = strchr(option, ':');
-			evdns_set_option(option, val ? val+1 : "", flags);
-		}
-	}
-#undef NEXT_TOKEN
-}
-
-/* exported function */
-/* returns: */
-/* 0 no errors */
-/* 1 failed to open file */
-/* 2 failed to stat file */
-/* 3 file too large */
-/* 4 out of memory */
-/* 5 short read from file */
-int
-evdns_resolv_conf_parse(int flags, const char *const filename) {
-	struct stat st;
-	int fd, n, r;
-	u8 *resolv;
-	char *start;
-	int err = 0;
-
-	evdns_log(EVDNS_LOG_DEBUG, "Parsing resolv.conf file %s", filename);
-
-	fd = tor_open_cloexec(filename, O_RDONLY, 0);
-	if (fd < 0) {
-		evdns_resolv_set_defaults(flags);
-		return 1;
-	}
-
-	if (fstat(fd, &st)) { err = 2; goto out1; }
-	if (!st.st_size) {
-		evdns_resolv_set_defaults(flags);
-		err = (flags & DNS_OPTION_NAMESERVERS) ? 6 : 0;
-		goto out1;
-	}
-	if (st.st_size > 65535) { err = 3; goto out1; }	 /* no resolv.conf should be any bigger */
-
-	resolv = (u8 *) mm_malloc((size_t)st.st_size + 1);
-	if (!resolv) { err = 4; goto out1; }
-
-    n = 0;
-	while ((r = (int)read(fd, resolv+n, (size_t)st.st_size-n)) > 0) {
-		n += r;
-		if (n == st.st_size)
-			break;
-		assert(n < st.st_size);
-	}
-	if (r < 0) { err = 5; goto out2; }
-	resolv[n] = 0;	 /* we malloced an extra byte; this should be fine. */
-
-	start = (char *) resolv;
-	for (;;) {
-		char *const newline = strchr(start, '\n');
-		if (!newline) {
-			resolv_conf_parse_line(start, flags);
-			break;
-		} else {
-			*newline = 0;
-			resolv_conf_parse_line(start, flags);
-			start = newline + 1;
-		}
-	}
-
-	if (!server_head && (flags & DNS_OPTION_NAMESERVERS)) {
-		/* no nameservers were configured. */
-		evdns_nameserver_ip_add("127.0.0.1");
-		err = 6;
-	}
-	if (flags & DNS_OPTION_SEARCH && (!global_search_state || global_search_state->num_domains == 0)) {
-		search_set_from_hostname();
-	}
-
-out2:
-	mm_free(resolv);
-out1:
-	close(fd);
-	return err;
-}
-
-#ifdef _WIN32
-/* Add multiple nameservers from a space-or-comma-separated list. */
-static int
-evdns_nameserver_ip_add_line(const char *ips) {
-	const char *addr;
-	char *buf;
-	int r;
-	while (*ips) {
-		while (ISSPACE(*ips) || *ips == ',' || *ips == '\t')
-			++ips;
-		addr = ips;
-		while (ISDIGIT(*ips) || *ips == '.' || *ips == ':' || *ips == '[' || *ips == ']')
-			++ips;
-		buf = mm_malloc(ips-addr+1);
-		if (!buf) return 4;
-		memcpy(buf, addr, ips-addr);
-		buf[ips-addr] = '\0';
-		r = evdns_nameserver_ip_add(buf);
-		mm_free(buf);
-		if (r) return r;
-	}
-	return 0;
-}
-
-typedef DWORD(WINAPI *GetNetworkParams_fn_t)(FIXED_INFO *, DWORD*);
-
-/* Use the windows GetNetworkParams interface in iphlpapi.dll to */
-/* figure out what our nameservers are. */
-static int
-load_nameservers_with_getnetworkparams(void)
-{
-	/* Based on MSDN examples and inspection of	 c-ares code. */
-	FIXED_INFO *fixed;
-	HMODULE handle = 0;
-	ULONG size = sizeof(FIXED_INFO);
-	void *buf = NULL;
-	int status = 0, r, added_any;
-	IP_ADDR_STRING *ns;
-	GetNetworkParams_fn_t fn;
-
-	if (!(handle = load_windows_system_library(TEXT("iphlpapi.dll")))) {
-		evdns_log(EVDNS_LOG_WARN, "Could not open iphlpapi.dll");
-		/* right now status = 0, doesn't that mean "good" - mikec */
-		status = -1;
-		goto done;
-	}
-	if (!(fn = (GetNetworkParams_fn_t) GetProcAddress(handle, TEXT("GetNetworkParams")))) {
-		evdns_log(EVDNS_LOG_WARN, "Could not get address of function.");
-		/* same as above */
-		status = -1;
-		goto done;
-	}
-
-	buf = mm_malloc(size);
-	if (!buf) { status = 4; goto done; }
-	fixed = buf;
-	r = fn(fixed, &size);
-	if (r != ERROR_SUCCESS && r != ERROR_BUFFER_OVERFLOW) {
-		status = -1;
-		goto done;
-	}
-	if (r != ERROR_SUCCESS) {
-		mm_free(buf);
-		buf = mm_malloc(size);
-		if (!buf) { status = 4; goto done; }
-		fixed = buf;
-		r = fn(fixed, &size);
-		if (r != ERROR_SUCCESS) {
-			evdns_log(EVDNS_LOG_DEBUG, "fn() failed.");
-			status = -1;
-			goto done;
-		}
-	}
-
-	assert(fixed);
-	added_any = 0;
-	ns = &(fixed->DnsServerList);
-	while (ns) {
-		r = evdns_nameserver_ip_add_line(ns->IpAddress.String);
-		if (r) {
-			evdns_log(EVDNS_LOG_DEBUG,"Could not add nameserver %s to list, "
-				"error: %d; status: %d",
-				(ns->IpAddress.String),(int)GetLastError(), r);
-			status = r;
-		} else {
-			evdns_log(EVDNS_LOG_DEBUG,"Successfully added %s as nameserver",ns->IpAddress.String);
-			added_any++;
-		}
-
-		ns = ns->Next;
-	}
-
-	if (!added_any) {
-		evdns_log(EVDNS_LOG_DEBUG, "No nameservers added.");
-		if (status == 0)
-			status = -1;
-	} else {
-		status = 0;
-	}
-
- done:
-	if (buf)
-		mm_free(buf);
-	if (handle)
-		FreeLibrary(handle);
-	return status;
-}
-
-static int
-config_nameserver_from_reg_key(HKEY key, const TCHAR *subkey)
-{
-	char *buf;
-	char ansibuf[MAX_PATH] = {0};
-	DWORD bufsz = 0, type = 0;
-	int status = 0;
-
-	if (RegQueryValueEx(key, subkey, 0, &type, NULL, &bufsz)
-		!= ERROR_MORE_DATA)
-		return -1;
-	if (!(buf = mm_malloc(bufsz)))
-		return -1;
-
-	if (RegQueryValueEx(key, subkey, 0, &type, (LPBYTE)buf, &bufsz)
-		== ERROR_SUCCESS && bufsz > 1) {
-		wcstombs(ansibuf,(wchar_t*)buf,MAX_PATH);/*XXXX UNICODE */
-		abuf[MAX_PATH-1] = '\0';
-		status = evdns_nameserver_ip_add_line(ansibuf);
-	}
-
-	mm_free(buf);
-	return status;
-}
-
-#define SERVICES_KEY TEXT("System\\CurrentControlSet\\Services\\")
-#define WIN_NS_9X_KEY  SERVICES_KEY TEXT("VxD\\MSTCP")
-#define WIN_NS_NT_KEY  SERVICES_KEY TEXT("Tcpip\\Parameters")
-
-static int
-load_nameservers_from_registry(void)
-{
-	int found = 0;
-	int r;
-	OSVERSIONINFO info;
-	memset(&info, 0, sizeof(info));
-	info.dwOSVersionInfoSize = sizeof (info);
-	GetVersionEx(&info);
-
-#define TRY(k, name)													\
-	if (!found && config_nameserver_from_reg_key(k,TEXT(name)) == 0) {	\
-		evdns_log(EVDNS_LOG_DEBUG,"Found nameservers in %s/%s",#k,name);		\
-		found = 1;														\
-	} else if (!found) {												\
-		evdns_log(EVDNS_LOG_DEBUG,"Didn't find nameservers in %s/%s",			\
-			#k,#name);													\
-	}
-
-	if (info.dwMajorVersion >= 5) { /* NT */
-		HKEY nt_key = 0, interfaces_key = 0;
-
-		if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0,
-						 KEY_READ, &nt_key) != ERROR_SUCCESS) {
-			evdns_log(EVDNS_LOG_DEBUG,"Couldn't open nt key, %d",(int)GetLastError());
-			return -1;
-		}
-		r = RegOpenKeyEx(nt_key, TEXT("Interfaces"), 0,
-						 KEY_QUERY_VALUE|KEY_ENUMERATE_SUB_KEYS,
-						 &interfaces_key);
-		if (r != ERROR_SUCCESS) {
-			evdns_log(EVDNS_LOG_DEBUG,"Couldn't open interfaces key, %d",(int)GetLastError());
-			return -1;
-		}
-		TRY(nt_key, "NameServer");
-		TRY(nt_key, "DhcpNameServer");
-		TRY(interfaces_key, "NameServer");
-		TRY(interfaces_key, "DhcpNameServer");
-		RegCloseKey(interfaces_key);
-		RegCloseKey(nt_key);
-	} else {
-		HKEY win_key = 0;
-		if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_9X_KEY, 0,
-						 KEY_READ, &win_key) != ERROR_SUCCESS) {
-			evdns_log(EVDNS_LOG_DEBUG, "Couldn't open registry key, %d", (int)GetLastError());
-			return -1;
-		}
-		TRY(win_key, "NameServer");
-		RegCloseKey(win_key);
-	}
-
-	if (found == 0) {
-		evdns_log(EVDNS_LOG_WARN,"Didn't find any nameservers.");
-	}
-
-	return found ? 0 : -1;
-#undef TRY
-}
-
-int
-evdns_config_windows_nameservers(void)
-{
-	if (load_nameservers_with_getnetworkparams() == 0)
-		return 0;
-	return load_nameservers_from_registry();
-}
-#endif
-
-int
-evdns_init(void)
-{
-		int res = 0;
-#ifdef _WIN32
-		evdns_config_windows_nameservers();
-#else
-		res = evdns_resolv_conf_parse(DNS_OPTIONS_ALL, "/etc/resolv.conf");
-#endif
-
-		return (res);
-}
-
-const char *
-evdns_err_to_string(int err)
-{
-	switch (err) {
-	case DNS_ERR_NONE: return "no error";
-	case DNS_ERR_FORMAT: return "misformatted query";
-	case DNS_ERR_SERVERFAILED: return "server failed";
-	case DNS_ERR_NOTEXIST: return "name does not exist";
-	case DNS_ERR_NOTIMPL: return "query not implemented";
-	case DNS_ERR_REFUSED: return "refused";
-
-	case DNS_ERR_TRUNCATED: return "reply truncated or ill-formed";
-	case DNS_ERR_UNKNOWN: return "unknown";
-	case DNS_ERR_TIMEOUT: return "request timed out";
-	case DNS_ERR_SHUTDOWN: return "dns subsystem shut down";
-	default: return "[Unknown error code]";
-	}
-}
-
-void
-evdns_shutdown(int fail_requests)
-{
-	struct nameserver *server, *server_next;
-	struct search_domain *dom, *dom_next;
-
-	while (req_head) {
-		if (fail_requests)
-			reply_callback(req_head, 0, DNS_ERR_SHUTDOWN, NULL);
-		request_finished(req_head, &req_head);
-	}
-	while (req_waiting_head) {
-		if (fail_requests)
-			reply_callback(req_waiting_head, 0, DNS_ERR_SHUTDOWN, NULL);
-		request_finished(req_waiting_head, &req_waiting_head);
-	}
-	global_requests_inflight = global_requests_waiting = 0;
-
-	for (server = server_head; server; server = server_next) {
-		server_next = server->next;
-		if (server->socket >= 0)
-			CLOSE_SOCKET(server->socket);
-		(void) event_del(&server->event);
-		del_timeout_event(server);
-		CLEAR(server);
-		mm_free(server);
-		if (server_next == server_head)
-			break;
-	}
-	server_head = NULL;
-	global_good_nameservers = 0;
-
-	if (global_search_state) {
-		for (dom = global_search_state->head; dom; dom = dom_next) {
-			dom_next = dom->next;
-			CLEAR(dom);
-			mm_free(dom);
-		}
-		CLEAR(global_search_state);
-		mm_free(global_search_state);
-		global_search_state = NULL;
-	}
-	evdns_log_fn = NULL;
-}
-
-#ifdef EVDNS_MAIN
-void
-main_callback(int result, char type, int count, int ttl,
-			  void *addrs, void *orig) {
-	char *n = (char*)orig;
-	int i;
-	for (i = 0; i < count; ++i) {
-		if (type == DNS_IPv4_A) {
-			printf("%s: %s\n", n, debug_ntoa(((u32*)addrs)[i]));
-		} else if (type == DNS_PTR) {
-			printf("%s: %s\n", n, ((char**)addrs)[i]);
-		}
-	}
-	if (!count) {
-		printf("%s: No answer (%d)\n", n, result);
-	}
-	fflush(stdout);
-}
-void
-evdns_server_callback(struct evdns_server_request *req, void *data)
-{
-	int i, r;
-	(void)data;
-	/* dummy; give 192.168.11.11 as an answer for all A questions,
-	 *	give foo.bar.example.com as an answer for all PTR questions. */
-	for (i = 0; i < req->nquestions; ++i) {
-		u32 ans = htonl(0xc0a80b0bUL);
-		if (req->questions[i]->type == EVDNS_TYPE_A &&
-			req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
-			printf(" -- replying for %s (A)\n", req->questions[i]->name);
-			r = evdns_server_request_add_a_reply(req, req->questions[i]->name,
-										  1, &ans, 10);
-			if (r<0)
-				printf("eeep, didn't work.\n");
-		} else if (req->questions[i]->type == EVDNS_TYPE_PTR &&
-				   req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
-			printf(" -- replying for %s (PTR)\n", req->questions[i]->name);
-			r = evdns_server_request_add_ptr_reply(req, NULL, req->questions[i]->name,
-											"foo.bar.example.com", 10);
-		} else {
-			printf(" -- skipping %s [%d %d]\n", req->questions[i]->name,
-				   req->questions[i]->type, req->questions[i]->dns_question_class);
-		}
-	}
-
-	r = evdns_server_request_respond(req, 0);
-	if (r<0)
-		printf("eeek, couldn't send reply.\n");
-}
-
-void
-logfn(int is_warn, const char *msg) {
-	(void) is_warn;
-	fprintf(stderr, "%s\n", msg);
-}
-int
-main(int c, char **v) {
-	int idx;
-	int reverse = 0, verbose = 1, servertest = 0;
-	if (c<2) {
-		fprintf(stderr, "syntax: %s [-x] [-v] hostname\n", v[0]);
-		fprintf(stderr, "syntax: %s [-servertest]\n", v[0]);
-		return 1;
-	}
-	idx = 1;
-	while (idx < c && v[idx][0] == '-') {
-		if (!strcmp(v[idx], "-x"))
-			reverse = 1;
-		else if (!strcmp(v[idx], "-v"))
-			verbose = 1;
-		else if (!strcmp(v[idx], "-servertest"))
-			servertest = 1;
-		else
-			fprintf(stderr, "Unknown option %s\n", v[idx]);
-		++idx;
-	}
-	event_init();
-	if (verbose)
-		evdns_set_log_fn(logfn);
-	evdns_resolv_conf_parse(DNS_OPTION_NAMESERVERS, "/etc/resolv.conf");
-	if (servertest) {
-		int sock;
-		struct sockaddr_in my_addr;
-#if 1
-		sock = tor_open_socket_nonblocking(PF_INET, SOCK_DGRAM, 0)
-#else
-		sock = tor_open_socket(PF_INET, SOCK_DGRAM, 0);
-		fcntl(sock, F_SETFL, O_NONBLOCK);
-#endif
-		my_addr.sin_family = AF_INET;
-		my_addr.sin_port = htons(10053);
-		my_addr.sin_addr.s_addr = INADDR_ANY;
-		if (bind(sock, (struct sockaddr*)&my_addr, sizeof(my_addr))<0) {
-			perror("bind");
-			exit(1);
-		}
-		evdns_add_server_port(sock, 0, evdns_server_callback, NULL);
-	}
-	for (; idx < c; ++idx) {
-		if (reverse) {
-			struct in_addr addr;
-			if (!inet_aton(v[idx], &addr)) {
-				fprintf(stderr, "Skipping non-IP %s\n", v[idx]);
-				continue;
-			}
-			fprintf(stderr, "resolving %s...\n",v[idx]);
-			evdns_resolve_reverse(&addr, 0, main_callback, v[idx]);
-		} else {
-			fprintf(stderr, "resolving (fwd) %s...\n",v[idx]);
-			evdns_resolve_ipv4(v[idx], 0, main_callback, v[idx]);
-		}
-	}
-	fflush(stdout);
-	event_dispatch();
-	return 0;
-}
-#endif
-
-/* Local Variables: */
-/* tab-width: 4 */
-/* c-basic-offset: 4 */
-/* indent-tabs-mode: t */
-/* End: */
-

src/ext/eventdns.h

@@ -1,337 +0,0 @@
-
-/*
- * The original DNS code is due to Adam Langley with heavy
- * modifications by Nick Mathewson.  Adam put his DNS software in the
- * public domain.  You can find his original copyright below.  Please,
- * aware that the code as part of libevent is governed by the 3-clause
- * BSD license above.
- *
- * This software is Public Domain. To view a copy of the public domain dedication,
- * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
- * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
- *
- * I ask and expect, but do not require, that all derivative works contain an
- * attribution similar to:
- *	Parts developed by Adam Langley <agl@imperialviolet.org>
- *
- * You may wish to replace the word "Parts" with something else depending on
- * the amount of original code.
- *
- * (Derivative works does not include programs which link against, run or include
- * the source verbatim in their source distributions)
- */
-
-/*
- * Welcome, gentle reader
- *
- * Async DNS lookups are really a whole lot harder than they should be,
- * mostly stemming from the fact that the libc resolver has never been
- * very good at them. Before you use this library you should see if libc
- * can do the job for you with the modern async call getaddrinfo_a
- * (see http://www.imperialviolet.org/page25.html#e498). Otherwise,
- * please continue.
- *
- * This code is based on libevent and you must call event_init before
- * any of the APIs in this file. You must also seed the OpenSSL random
- * source if you are using OpenSSL for ids (see below).
- *
- * This library is designed to be included and shipped with your source
- * code. You statically link with it. You should also test for the
- * existence of strtok_r and define HAVE_STRTOK_R if you have it.
- *
- * The DNS protocol requires a good source of id numbers and these
- * numbers should be unpredictable for spoofing reasons. There are
- * three methods for generating them here and you must define exactly
- * one of them. In increasing order of preference:
- *
- * DNS_USE_GETTIMEOFDAY_FOR_ID:
- *   Using the bottom 16 bits of the usec result from gettimeofday. This
- *   is a pretty poor solution but should work anywhere.
- * DNS_USE_CPU_CLOCK_FOR_ID:
- *  Using the bottom 16 bits of the nsec result from the CPU's time
- *  counter. This is better, but may not work everywhere. Requires
- *  POSIX realtime support and you'll need to link against -lrt on
- *  glibc systems at least.
- * DNS_USE_OPENSSL_FOR_ID:
- *  Uses the OpenSSL RAND_bytes call to generate the data. You must
- *  have seeded the pool before making any calls to this library.
- *
- * The library keeps track of the state of nameservers and will avoid
- * them when they go down. Otherwise it will round robin between them.
- *
- * Quick start guide:
- *	 #include "evdns.h"
- *	 void callback(int result, char type, int count, int ttl,
- *     void *addresses, void *arg);
- *	 evdns_resolv_conf_parse(DNS_OPTIONS_ALL, "/etc/resolv.conf");
- *	 evdns_resolve("www.hostname.com", 0, callback, NULL);
- *
- * When the lookup is complete the callback function is called. The
- * first argument will be one of the DNS_ERR_* defines in evdns.h.
- * Hopefully it will be DNS_ERR_NONE, in which case type will be
- * DNS_IPv4_A, count will be the number of IP addresses, ttl is the time
- * which the data can be cached for (in seconds), addresses will point
- * to an array of uint32_t's and arg will be whatever you passed to
- * evdns_resolve.
- *
- * Searching:
- *
- * In order for this library to be a good replacement for glibc's resolver it
- * supports searching. This involves setting a list of default domains, in
- * which names will be queried for. The number of dots in the query name
- * determines the order in which this list is used.
- *
- * Searching appears to be a single lookup from the point of view of the API,
- * although many DNS queries may be generated from a single call to
- * evdns_resolve. Searching can also drastically slow down the resolution
- * of names.
- *
- * To disable searching:
- *	 1. Never set it up. If you never call evdns_resolv_conf_parse or
- *   evdns_search_add then no searching will occur.
- *
- *	 2. If you do call evdns_resolv_conf_parse then don't pass
- *   DNS_OPTION_SEARCH (or DNS_OPTIONS_ALL, which implies it).
- *
- *	 3. When calling evdns_resolve, pass the DNS_QUERY_NO_SEARCH flag.
- *
- * The order of searches depends on the number of dots in the name. If the
- * number is greater than the ndots setting then the names is first tried
- * globally. Otherwise each search domain is appended in turn.
- *
- * The ndots setting can either be set from a resolv.conf, or by calling
- * evdns_search_ndots_set.
- *
- * For example, with ndots set to 1 (the default) and a search domain list of
- * ["myhome.net"]:
- *	Query: www
- *	Order: www.myhome.net, www.
- *
- *	Query: www.abc
- *	Order: www.abc., www.abc.myhome.net
- *
- * API reference:
- *
- * int evdns_nameserver_add(uint32_t address)
- *	 Add a nameserver. The address should be an IP address in
- *	 network byte order. The type of address is chosen so that
- *	 it matches in_addr.s_addr.
- *	 Returns non-zero on error.
- *
- * int evdns_nameserver_ip_add(const char *ip_as_string)
- *	 This wraps the above function by parsing a string as an IP
- *	 address and adds it as a nameserver.
- *	 Returns non-zero on error
- *
- * int evdns_resolve(const char *name, int flags,
- *	      evdns_callback_type callback,
- *	      void *ptr)
- *	 Resolve a name. The name parameter should be a DNS name.
- *	 The flags parameter should be 0, or DNS_QUERY_NO_SEARCH
- *	 which disables searching for this query. (see defn of
- *	 searching above).
- *
- *	 The callback argument is a function which is called when
- *	 this query completes and ptr is an argument which is passed
- *	 to that callback function.
- *
- *	 Returns non-zero on error
- *
- * void evdns_search_clear()
- *	 Clears the list of search domains
- *
- * void evdns_search_add(const char *domain)
- *	 Add a domain to the list of search domains
- *
- * void evdns_search_ndots_set(int ndots)
- *	 Set the number of dots which, when found in a name, causes
- *	 the first query to be without any search domain.
- *
- * int evdns_count_nameservers(void)
- *	 Return the number of configured nameservers (not necessarily the
- *	 number of running nameservers).  This is useful for double-checking
- *	 whether our calls to the various nameserver configuration functions
- *	 have been successful.
- *
- * int evdns_clear_nameservers_and_suspend(void)
- *	 Remove all currently configured nameservers, and suspend all pending
- *	 resolves.	Resolves will not necessarily be re-attempted until
- *	 evdns_resume() is called.
- *
- * int evdns_resume(void)
- *	 Re-attempt resolves left in limbo after an earlier call to
- *	 evdns_clear_nameservers_and_suspend().
- *
- * int evdns_config_windows_nameservers(void)
- *	 Attempt to configure a set of nameservers based on platform settings on
- *	 a win32 host.	Preferentially tries to use GetNetworkParams; if that fails,
- *	 looks in the registry.	 Returns 0 on success, nonzero on failure.
- *
- * int evdns_resolv_conf_parse(int flags, const char *filename)
- *	 Parse a resolv.conf like file from the given filename.
- *
- *	 See the man page for resolv.conf for the format of this file.
- *	 The flags argument determines what information is parsed from
- *	 this file:
- *	   DNS_OPTION_SEARCH - domain, search and ndots options
- *	   DNS_OPTION_NAMESERVERS - nameserver lines
- *	   DNS_OPTION_MISC - timeout and attempts options
- *	   DNS_OPTIONS_ALL - all of the above
- *	 The following directives are not parsed from the file:
- *	   sortlist, rotate, no-check-names, inet6, debug
- *
- *	 Returns non-zero on error:
- *	  0 no errors
- *	  1 failed to open file
- *	  2 failed to stat file
- *	  3 file too large
- *	  4 out of memory
- *	  5 short read from file
- *        6 no nameservers in file
- *
- * Internals:
- *
- * Requests are kept in two queues. The first is the inflight queue. In
- * this queue requests have an allocated transaction id and nameserver.
- * They will soon be transmitted if they haven't already been.
- *
- * The second is the waiting queue. The size of the inflight ring is
- * limited and all other requests wait in waiting queue for space. This
- * bounds the number of concurrent requests so that we don't flood the
- * nameserver. Several algorithms require a full walk of the inflight
- * queue and so bounding its size keeps thing going nicely under huge
- * (many thousands of requests) loads.
- *
- * If a nameserver loses too many requests it is considered down and we
- * try not to use it. After a while we send a probe to that nameserver
- * (a lookup for google.com) and, if it replies, we consider it working
- * again. If the nameserver fails a probe we wait longer to try again
- * with the next probe.
- */
-
-#ifndef TOR_EVENTDNS_H
-#define TOR_EVENTDNS_H
-
-/* Error codes 0-5 are as described in RFC 1035. */
-#define DNS_ERR_NONE 0
-/* The name server was unable to interpret the query */
-#define DNS_ERR_FORMAT 1
-/* The name server was unable to process this query due to a problem with the
- * name server */
-#define DNS_ERR_SERVERFAILED 2
-/* The domain name does not exist */
-#define DNS_ERR_NOTEXIST 3
-/* The name server does not support the requested kind of query */
-#define DNS_ERR_NOTIMPL 4
-/* The name server refuses to reform the specified operation for policy
- * reasons */
-#define DNS_ERR_REFUSED 5
-/* The reply was truncated or ill-formated */
-#define DNS_ERR_TRUNCATED 65
-/* An unknown error occurred */
-#define DNS_ERR_UNKNOWN 66
-/* Communication with the server timed out */
-#define DNS_ERR_TIMEOUT 67
-/* The request was canceled because the DNS subsystem was shut down. */
-#define DNS_ERR_SHUTDOWN 68
-
-#define DNS_IPv4_A 1
-#define DNS_PTR 2
-#define DNS_IPv6_AAAA 3
-
-#define DNS_QUERY_NO_SEARCH 1
-
-#define DNS_OPTION_SEARCH 1
-#define DNS_OPTION_NAMESERVERS 2
-#define DNS_OPTION_MISC 4
-#define DNS_OPTIONS_ALL 7
-
-/*
- * The callback that contains the results from a lookup.
- * - type is either DNS_IPv4_A or DNS_IPv6_AAAA or DNS_PTR
- * - count contains the number of addresses of form type
- * - ttl is the number of seconds the resolution may be cached for.
- * - addresses needs to be cast according to type
- */
-typedef void (*evdns_callback_type) (int result, char type, int count, int ttl, void *addresses, void *arg);
-
-int evdns_init(void);
-void evdns_shutdown(int fail_requests);
-const char *evdns_err_to_string(int err);
-int evdns_nameserver_add(uint32_t address);
-int evdns_count_nameservers(void);
-int evdns_clear_nameservers_and_suspend(void);
-int evdns_resume(void);
-int evdns_nameserver_ip_add(const char *ip_as_string);
-int evdns_nameserver_sockaddr_add(const struct sockaddr *sa, socklen_t len);
-void evdns_set_default_outgoing_bind_address(const struct sockaddr *addr, socklen_t addrlen);
-int evdns_resolve_ipv4(const char *name, int flags, evdns_callback_type callback, void *ptr);
-int evdns_resolve_ipv6(const char *name, int flags, evdns_callback_type callback, void *ptr);
-struct in_addr;
-struct in6_addr;
-int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
-int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
-int evdns_set_option(const char *option, const char *val, int flags);
-int evdns_resolv_conf_parse(int flags, const char *);
-#ifdef _WIN32
-int evdns_config_windows_nameservers(void);
-#endif
-void evdns_search_clear(void);
-void evdns_search_add(const char *domain);
-void evdns_search_ndots_set(const int ndots);
-
-typedef void (*evdns_debug_log_fn_type)(int is_warning, const char *msg);
-void evdns_set_log_fn(evdns_debug_log_fn_type fn);
-
-void evdns_set_transaction_id_fn(uint16_t (*fn)(void));
-void evdns_set_random_bytes_fn(void (*fn)(char *, size_t));
-
-#define DNS_NO_SEARCH 1
-
-/* Structures and functions used to implement a DNS server. */
-
-struct evdns_server_request {
-	int flags;
-	int nquestions;
-	struct evdns_server_question **questions;
-};
-struct evdns_server_question {
-	int type;
-	int dns_question_class;
-	char name[1];
-};
-typedef void (*evdns_request_callback_fn_type)(struct evdns_server_request *, void *);
-#define EVDNS_ANSWER_SECTION 0
-#define EVDNS_AUTHORITY_SECTION 1
-#define EVDNS_ADDITIONAL_SECTION 2
-
-#define EVDNS_TYPE_A	   1
-#define EVDNS_TYPE_NS	   2
-#define EVDNS_TYPE_CNAME   5
-#define EVDNS_TYPE_SOA	   6
-#define EVDNS_TYPE_PTR	  12
-#define EVDNS_TYPE_MX	  15
-#define EVDNS_TYPE_TXT	  16
-#define EVDNS_TYPE_AAAA	  28
-
-#define EVDNS_QTYPE_AXFR 252
-#define EVDNS_QTYPE_ALL	 255
-
-#define EVDNS_CLASS_INET   1
-
-struct evdns_server_port *evdns_add_server_port(tor_socket_t socket, int is_tcp, evdns_request_callback_fn_type callback, void *user_data);
-void evdns_close_server_port(struct evdns_server_port *port);
-
-int evdns_server_request_add_reply(struct evdns_server_request *req, int section, const char *name, int type, int class, int ttl, int datalen, int is_name, const char *data);
-int evdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl);
-int evdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl);
-int evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl);
-int evdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl);
-
-struct sockaddr;
-int evdns_server_request_get_requesting_addr(struct evdns_server_request *req, struct sockaddr *sa, int addr_len);
-
-int evdns_server_request_respond(struct evdns_server_request *req, int err);
-int evdns_server_request_drop(struct evdns_server_request *req);
-
-#endif	// !EVENTDNS_H

src/ext/include.am

@@ -5,7 +5,6 @@ EXTRA_DIST += src/ext/README
 
 EXTHEADERS = \
   src/ext/ht.h		\
-  src/ext/eventdns.h	\
   src/ext/tinytest.h	\
   src/ext/tor_readpassphrase.h \
   src/ext/strlcat.c	\

src/or/config.c

@@ -7204,8 +7204,6 @@ init_libevent(const or_options_t *options)
    */
   suppress_libevent_log_msg("Function not implemented");
 
-  tor_check_libevent_header_compatibility();
-
   memset(&cfg, 0, sizeof(cfg));
   cfg.disable_iocp = options->DisableIOCP;
   cfg.num_cpus = get_num_cpus(options);

src/or/control.c

@@ -51,11 +51,7 @@
 #include <sys/resource.h>
 #endif
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 #include "crypto_s2k.h"
 #include "procmon.h"

src/or/cpuworker.c

@@ -23,11 +23,7 @@
 #include "router.h"
 #include "workqueue.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 static void queue_pending_tasks(void);
 

src/or/dns.c

@@ -27,61 +27,8 @@
 #include "router.h"
 #include "ht.h"
 #include "sandbox.h"
-#ifdef HAVE_EVENT2_DNS_H
 #include <event2/event.h>
 #include <event2/dns.h>
-#else
-#include <event.h>
-#include "eventdns.h"
-#ifndef HAVE_EVDNS_SET_DEFAULT_OUTGOING_BIND_ADDRESS
-#define HAVE_EVDNS_SET_DEFAULT_OUTGOING_BIND_ADDRESS
-#endif
-#endif
-
-#ifndef HAVE_EVENT2_DNS_H
-struct evdns_base;
-struct evdns_request;
-#define evdns_base_new(x,y) tor_malloc(1)
-#define evdns_base_clear_nameservers_and_suspend(base) \
-  evdns_clear_nameservers_and_suspend()
-#define evdns_base_search_clear(base) evdns_search_clear()
-#define evdns_base_set_default_outgoing_bind_address(base, a, len)  \
-  evdns_set_default_outgoing_bind_address((a),(len))
-#define evdns_base_resolv_conf_parse(base, options, fname) \
-  evdns_resolv_conf_parse((options), (fname))
-#define evdns_base_count_nameservers(base)      \
-  evdns_count_nameservers()
-#define evdns_base_resume(base)                 \
-  evdns_resume()
-#define evdns_base_config_windows_nameservers(base)     \
-  evdns_config_windows_nameservers()
-#define evdns_base_set_option_(base, opt, val) \
-  evdns_set_option((opt),(val),DNS_OPTIONS_ALL)
-/* Note: our internal eventdns.c, plus Libevent 1.4, used a 1 return to
- * signify failure to launch a resolve. Libevent 2.0 uses a -1 return to
- * signify a failure on a resolve, though if we're on Libevent 2.0, we should
- * have event2/dns.h and never hit these macros.  Regardless, 0 is success. */
-#define evdns_base_resolve_ipv4(base, addr, options, cb, ptr) \
-  ((evdns_resolve_ipv4((addr), (options), (cb), (ptr))!=0)    \
-   ? NULL : ((void*)1))
-#define evdns_base_resolve_ipv6(base, addr, options, cb, ptr) \
-  ((evdns_resolve_ipv6((addr), (options), (cb), (ptr))!=0)    \
-   ? NULL : ((void*)1))
-#define evdns_base_resolve_reverse(base, addr, options, cb, ptr)        \
-  ((evdns_resolve_reverse((addr), (options), (cb), (ptr))!=0)           \
-   ? NULL : ((void*)1))
-#define evdns_base_resolve_reverse_ipv6(base, addr, options, cb, ptr)   \
-  ((evdns_resolve_reverse_ipv6((addr), (options), (cb), (ptr))!=0)      \
-   ? NULL : ((void*)1))
-
-#elif defined(LIBEVENT_VERSION_NUMBER) && LIBEVENT_VERSION_NUMBER < 0x02000303
-#define evdns_base_set_option_(base, opt, val) \
-  evdns_base_set_option((base), (opt),(val),DNS_OPTIONS_ALL)
-
-#else
-#define evdns_base_set_option_ evdns_base_set_option
-
-#endif
 
 /** How long will we wait for an answer from the resolver before we decide
  * that the resolver is wedged? */
@@ -1373,23 +1320,6 @@ configure_nameservers(int force)
     }
   }
 
-#ifdef HAVE_EVDNS_SET_DEFAULT_OUTGOING_BIND_ADDRESS
-  if (! tor_addr_is_null(&options->OutboundBindAddressIPv4_)) {
-    int socklen;
-    struct sockaddr_storage ss;
-    socklen = tor_addr_to_sockaddr(&options->OutboundBindAddressIPv4_, 0,
-                                   (struct sockaddr *)&ss, sizeof(ss));
-    if (socklen <= 0) {
-      log_warn(LD_BUG, "Couldn't convert outbound bind address to sockaddr."
-               " Ignoring.");
-    } else {
-      evdns_base_set_default_outgoing_bind_address(the_evdns_base,
-                                                   (struct sockaddr *)&ss,
-                                                   socklen);
-    }
-  }
-#endif
-
   evdns_set_log_fn(evdns_log_cb);
   if (conf_fname) {
     log_debug(LD_FS, "stat()ing %s", conf_fname);
@@ -1454,7 +1384,7 @@ configure_nameservers(int force)
   }
 #endif
 
-#define SET(k,v)  evdns_base_set_option_(the_evdns_base, (k), (v))
+#define SET(k,v)  evdns_base_set_option(the_evdns_base, (k), (v))
 
   if (evdns_base_count_nameservers(the_evdns_base) == 1) {
     SET("max-timeouts:", "16");

src/or/dnsserv.c

@@ -17,14 +17,10 @@
 #include "control.h"
 #include "main.h"
 #include "policies.h"
-#ifdef HAVE_EVENT2_DNS_H
 #include <event2/dns.h>
 #include <event2/dns_compat.h>
 /* XXXX this implies we want an improved evdns  */
 #include <event2/dns_struct.h>
-#else
-#include "eventdns.h"
-#endif
 
 /** Helper function: called by evdns whenever the client sends a request to our
  * DNSPort.  We need to eventually answer the request <b>req</b>.

src/or/include.am

@@ -17,12 +17,6 @@ endif
 
 EXTRA_DIST+= src/or/ntmain.c src/or/Makefile.nmake
 
-if USE_EXTERNAL_EVDNS
-evdns_source=
-else
-evdns_source=src/ext/eventdns.c
-endif
-
 LIBTOR_A_SOURCES = \
 	src/or/addressmap.c				\
 	src/or/buffers.c				\
@@ -86,7 +80,6 @@ LIBTOR_A_SOURCES = \
 	src/or/status.c					\
 	src/or/torcert.c				\
 	src/or/onion_ntor.c				\
-	$(evdns_source)					\
 	$(tor_platform_source)
 
 src_or_libtor_a_SOURCES = $(LIBTOR_A_SOURCES)

src/or/main.c

@@ -69,11 +69,7 @@
 #include "memarea.h"
 #include "sandbox.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 #ifdef USE_BUFFEREVENTS
 #include <event2/bufferevent.h>

src/or/ntmain.c

@@ -16,11 +16,7 @@
 #include "main.h"
 #include "ntmain.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 #include <windows.h>
 #define GENSRV_SERVICENAME  "tor"

src/or/periodic.c

@@ -12,11 +12,7 @@
 #include "config.h"
 #include "periodic.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 /** We disable any interval greater than this number of seconds, on the
  * grounds that it is probably an absolute time mistakenly passed in as a

src/or/scheduler.c

@@ -15,11 +15,7 @@
 #define SCHEDULER_PRIVATE_
 #include "scheduler.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 /*
  * Scheduler high/low watermarks

src/test/test-timers.c

@@ -7,11 +7,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 #include "compat.h"
 #include "compat_libevent.h"

src/test/test_compat_libevent.c

@@ -9,15 +9,11 @@
 
 #include "compat_libevent.h"
 
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
 #include <event2/thread.h>
 #ifdef USE_BUFFEREVENTS
 #include <event2/bufferevent.h>
 #endif
-#else
-#include <event.h>
-#endif
 
 #include "log_test_helpers.h"
 
@@ -106,98 +102,6 @@ test_compat_libevent_logging_callback(void *ignored)
   teardown_capture_of_logs(previous_log);
 }
 
-static void
-test_compat_libevent_le_versions_compatibility(void *ignored)
-{
-  (void)ignored;
-  int res;
-
-  res = le_versions_compatibility(LE_OTHER);
-  tt_int_op(res, OP_EQ, 0);
-
-  res = le_versions_compatibility(V_OLD(0,9,'c'));
-  tt_int_op(res, OP_EQ, 1);
-
-  res = le_versions_compatibility(V(1,3,98));
-  tt_int_op(res, OP_EQ, 2);
-
-  res = le_versions_compatibility(V(1,4,98));
-  tt_int_op(res, OP_EQ, 3);
-
-  res = le_versions_compatibility(V(1,5,0));
-  tt_int_op(res, OP_EQ, 4);
-
-  res = le_versions_compatibility(V(2,0,0));
-  tt_int_op(res, OP_EQ, 4);
-
-  res = le_versions_compatibility(V(2,0,2));
-  tt_int_op(res, OP_EQ, 5);
-
- done:
-  (void)0;
-}
-
-static void
-test_compat_libevent_tor_decode_libevent_version(void *ignored)
-{
-  (void)ignored;
-  le_version_t res;
-
-  res = tor_decode_libevent_version("SOMETHING WRONG");
-  tt_int_op(res, OP_EQ, LE_OTHER);
-
-  res = tor_decode_libevent_version("1.4.11");
-  tt_int_op(res, OP_EQ, V(1,4,11));
-
-  res = tor_decode_libevent_version("1.4.12b-stable");
-  tt_int_op(res, OP_EQ, V(1,4,12));
-
-  res = tor_decode_libevent_version("1.4.17b_stable");
-  tt_int_op(res, OP_EQ, V(1,4,17));
-
-  res = tor_decode_libevent_version("1.4.12!stable");
-  tt_int_op(res, OP_EQ, LE_OTHER);
-
-  res = tor_decode_libevent_version("1.4.12b!stable");
-  tt_int_op(res, OP_EQ, LE_OTHER);
-
-  res = tor_decode_libevent_version("1.4.13-");
-  tt_int_op(res, OP_EQ, V(1,4,13));
-
-  res = tor_decode_libevent_version("1.4.14_");
-  tt_int_op(res, OP_EQ, V(1,4,14));
-
-  res = tor_decode_libevent_version("1.4.15c-");
-  tt_int_op(res, OP_EQ, V(1,4,15));
-
-  res = tor_decode_libevent_version("1.4.16c_");
-  tt_int_op(res, OP_EQ, V(1,4,16));
-
-  res = tor_decode_libevent_version("1.4.17-s");
-  tt_int_op(res, OP_EQ, V(1,4,17));
-
-  res = tor_decode_libevent_version("1.5");
-  tt_int_op(res, OP_EQ, V(1,5,0));
-
-  res = tor_decode_libevent_version("1.2");
-  tt_int_op(res, OP_EQ, V(1,2,0));
-
-  res = tor_decode_libevent_version("1.2-");
-  tt_int_op(res, OP_EQ, LE_OTHER);
-
-  res = tor_decode_libevent_version("1.6e");
-  tt_int_op(res, OP_EQ, V_OLD(1,6,'e'));
-
- done:
-  (void)0;
-}
-
-#if defined(LIBEVENT_VERSION)
-#define HEADER_VERSION LIBEVENT_VERSION
-#elif defined(_EVENT_VERSION)
-#define HEADER_VERSION _EVENT_VERSION
-#endif
-
 static void
 test_compat_libevent_header_version(void *ignored)
 {
@@ -205,7 +109,7 @@ test_compat_libevent_header_version(void *ignored)
   const char *res;
 
   res = tor_libevent_get_header_version_str();
-  tt_str_op(res, OP_EQ, HEADER_VERSION);
+  tt_str_op(res, OP_EQ, LIBEVENT_VERSION);
 
  done:
   (void)0;
@@ -214,10 +118,6 @@ test_compat_libevent_header_version(void *ignored)
 struct testcase_t compat_libevent_tests[] = {
   { "logging_callback", test_compat_libevent_logging_callback,
     TT_FORK, NULL, NULL },
-  { "le_versions_compatibility",
-    test_compat_libevent_le_versions_compatibility, 0, NULL, NULL },
-  { "tor_decode_libevent_version",
-    test_compat_libevent_tor_decode_libevent_version, 0, NULL, NULL },
   { "header_version", test_compat_libevent_header_version, 0, NULL, NULL },
   END_OF_TESTCASES
 };

src/test/test_scheduler.c

@@ -5,12 +5,7 @@
 
 #include "orconfig.h"
 
-/* Libevent stuff */
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 #define TOR_CHANNEL_INTERNAL_
 #define CHANNEL_PRIVATE_
@@ -90,9 +85,7 @@ mock_event_free_all(void)
 static void
 mock_event_init(void)
 {
-#ifdef HAVE_EVENT2_EVENT_H
   struct event_config *cfg = NULL;
-#endif
 
   tt_ptr_op(mock_event_base, ==, NULL);
 
@@ -102,7 +95,6 @@ mock_event_init(void)
    */
 
   if (!mock_event_base) {
-#ifdef HAVE_EVENT2_EVENT_H
     cfg = event_config_new();
 #if LIBEVENT_VERSION_NUMBER >= V(2,0,9)
     /* We can enable changelist support with epoll, since we don't give
@@ -111,9 +103,6 @@ mock_event_init(void)
 #endif
     mock_event_base = event_base_new_with_config(cfg);
     event_config_free(cfg);
-#else
-    mock_event_base = event_init();
-#endif
   }
 
   tt_assert(mock_event_base != NULL);

src/test/test_workqueue.c

@@ -12,11 +12,7 @@
 #include "compat_libevent.h"
 
 #include <stdio.h>
-#ifdef HAVE_EVENT2_EVENT_H
 #include <event2/event.h>
-#else
-#include <event.h>
-#endif
 
 #define MAX_INFLIGHT (1<<16)
 

src/win32/orconfig.h

@@ -226,9 +226,7 @@
 #define HAVE_STRUCT_IN6_ADDR
 #define RSHIFT_DOES_SIGN_EXTEND
 #define FLEXIBLE_ARRAY_MEMBER 0
-#define HAVE_EVENT2_EVENT_H
 #define SHARE_DATADIR ""
-#define HAVE_EVENT2_DNS_H
 #define USE_CURVE25519_DONNA
 
 #define ENUM_VALS_ARE_SIGNED 1