Add some missing doxygen for ipv6 exit code

src/common/address.c

@@ -181,7 +181,9 @@ tor_addr_make_unspec(tor_addr_t *a)
   a->family = AF_UNSPEC;
 }
 
-/** DOCDOC */
+/** Set address <a>a</b> to the null address in address family <b>family</b>.
+ * The null address for AF_INET is 0.0.0.0.  The null address for AF_INET6 is
+ * [::].  AF_UNSPEC is all null. */
 void
 tor_addr_make_null(tor_addr_t *a, sa_family_t family)
 {

src/or/connection_edge.c

@@ -392,10 +392,17 @@ connection_edge_finished_flushing(edge_connection_t *conn)
   return 0;
 }
 
-/** DOCDOC */
+/** Longest size for the relay payload of a RELAY_CONNECTED cell that we're
+ * able to generate. */
+/* 4 zero bytes; 1 type byte; 16 byte IPv6 address; 4 byte TTL. */
 #define MAX_CONNECTED_CELL_PAYLOAD_LEN 25
 
-/** DOCDOC */
+/** Set the buffer at <b>payload_out</b> -- which must have at least
+ * MAX_CONNECTED_CELL_PAYLOAD_LEN bytes available -- to the body of a
+ * RELAY_CONNECTED cell indicating that we have connected to <b>addr</b>, and
+ * that the name resolution that led us to <b>addr</b> will be valid for
+ * <b>ttl</b> seconds. Return -1 on error, or the number of bytes used on
+ * success. */
 /* private */int
 connected_cell_format_payload(uint8_t *payload_out,
                               const tor_addr_t *addr,
@@ -404,6 +411,9 @@ connected_cell_format_payload(uint8_t *payload_out,
   const sa_family_t family = tor_addr_family(addr);
   int connected_payload_len;
 
+  /* should be needless */
+  memset(payload_out, 0, MAX_CONNECTED_CELL_PAYLOAD_LEN);
+
   if (family == AF_INET) {
     set_uint32(payload_out, tor_addr_to_ipv4n(addr));
     connected_payload_len = 4;
@@ -1672,7 +1682,8 @@ connection_ap_supports_optimistic_data(const entry_connection_t *conn)
   return conn->may_use_optimistic_data;
 }
 
-/** DOCDOC */
+/** Return a bitmask of BEGIN_FLAG_* flags that we should transmit in the
+ * RELAY_BEGIN cell for <b>ap_conn</b>. */
 static uint32_t
 connection_ap_get_begincell_flags(entry_connection_t *ap_conn)
 {
@@ -1680,12 +1691,16 @@ connection_ap_get_begincell_flags(entry_connection_t *ap_conn)
   const node_t *exitnode = NULL;
   const crypt_path_t *cpath_layer = edge_conn->cpath_layer;
   uint32_t flags = 0;
+
+  /* No flags for begindir */
   if (ap_conn->use_begindir)
     return 0;
 
+  /* No flags for hidden services. */
   if (edge_conn->on_circuit->purpose != CIRCUIT_PURPOSE_C_GENERAL)
     return 0;
 
+  /* If only IPv4 is supported, no flags */
   if (ap_conn->ipv4_traffic_ok && !ap_conn->ipv6_traffic_ok)
     return 0;
 
@@ -1704,6 +1719,8 @@ connection_ap_get_begincell_flags(entry_connection_t *ap_conn)
     if (compare_tor_addr_to_node_policy(&a, ap_conn->socks_request->port,
                                         exitnode)
         != ADDR_POLICY_REJECTED) {
+      /* Only say "IPv6 OK" if the exit node supports IPv6. Otherwise there's
+       * no point. */
       flags |= BEGIN_FLAG_IPV6_OK;
     }
   }
@@ -2184,7 +2201,10 @@ connection_ap_handshake_socks_reply(entry_connection_t *conn, char *reply,
   return;
 }
 
-/* DOCDOC */
+/** Read a RELAY_BEGIN or RELAY_BEGINDIR cell from <b>cell</b>, decode it, and
+ * place the result in <b>bcell</b>.  On success return 0; on failure return
+ * <0 and set *<b>end_reason_out</b> to the end reason we should send back to
+ * the client. */
 /* static */ int
 begin_cell_parse(const cell_t *cell, begin_cell_t *bcell,
                  uint8_t *end_reason_out)

src/or/connection_edge.h

@@ -91,19 +91,41 @@ int connection_edge_update_circuit_isolation(const entry_connection_t *conn,
                                              int dry_run);
 void circuit_clear_isolation(origin_circuit_t *circ);
 
-/* DOCDOC*/
+/** @name Begin-cell flags
+ *
+ * These flags are used in RELAY_BEGIN cells to change the default behavior
+ * of the cell.
+ *
+ * @{
+ **/
+/** When this flag is set, the client is willing to get connected to IPv6
+ * addresses */
 #define BEGIN_FLAG_IPV6_OK        (1u<<0)
+/** When this flag is set, the client DOES NOT support connecting to IPv4
+ * addresses.  (The sense of this flag is inverted from IPV6_OK, so that the
+ * old default behavior of Tor is equivalent to having all flags set to 0.)
+ **/
 #define BEGIN_FLAG_IPV4_NOT_OK    (1u<<1)
+/** When this flag is set, if we find both an IPv4 and an IPv6 address,
+ * we use the IPv6 address.  Otherwise we use the IPv4 address. */
 #define BEGIN_FLAG_IPV6_PREFERRED (1u<<2)
+/**@}*/
 
 #ifdef CONNECTION_EDGE_PRIVATE
 
-/*DOCDOC*/
+/** A parsed BEGIN or BEGIN_DIR cell */
 typedef struct begin_cell_t {
+  /** The address the client has asked us to connect to, or NULL if this is
+   * a BEGIN_DIR cell*/
   char *address;
+  /** The flags specified in the BEGIN cell's body.  One or more of
+   * BEGIN_FLAG_*. */
   uint32_t flags;
+  /** The client's requested port. */
   uint16_t port;
+  /** The client's requested Stream ID */
   uint16_t stream_id;
+  /** True iff this is a BEGIN_DIR cell. */
   unsigned is_begindir : 1;
 } begin_cell_t;
 

src/or/dns.c

@@ -127,10 +127,16 @@ typedef struct pending_connection_t {
  * connections, and should appear in the hash table. */
 #define CACHE_STATE_CACHED 2
 
-/* DOCDOC */
+/** @name status values for a single DNS request.
+ *
+ * @{ */
+/** The DNS request is in progress. */
 #define RES_STATUS_INFLIGHT 1
+/** The DNS request finished and gave an answer */
 #define RES_STATUS_DONE_OK 2
+/** The DNS request finished and gave an error */
 #define RES_STATUS_DONE_ERR 3
+/**@}*/
 
 /** A DNS request: possibly completed, possibly pending; cached_resolve
  * structs are stored at the OR side in a hash table, and as a linked
@@ -138,27 +144,34 @@ typedef struct pending_connection_t {
  */
 typedef struct cached_resolve_t {
   HT_ENTRY(cached_resolve_t) node;
-  uint32_t magic;
+  uint32_t magic;  /**< Must be CACHED_RESOLVE_MAGIC */
   char address[MAX_ADDRESSLEN]; /**< The hostname to be resolved. */
 
   union {
-    uint32_t addr_ipv4; /**< IPv4 addr for <b>address</b>. */
-    int err_ipv4;
-  } result_ipv4;
+    uint32_t addr_ipv4; /**< IPv4 addr for <b>address</b>, if successful */
+    int err_ipv4; /**< One of DNS_ERR_*, if IPv4 lookup failed. */
+  } result_ipv4; /**< Outcome of IPv4 lookup */
   union {
-    struct in6_addr addr_ipv6;
-    int err_ipv6;
-  } result_ipv6;
+    struct in6_addr addr_ipv6; /**< IPv6 addr for <b>address</b>, if
+                                * successful */
+    int err_ipv6; /**< One of DNS_ERR_*, if IPv6 lookup failed. */
+  } result_ipv6; /**< Outcome of IPv6 lookup, if any */
   union {
-    char *hostname;
-    int err_hostname;
+    char *hostname; /** A hostname, if PTR lookup happened successfully*/
+    int err_hostname; /** One of DNS_ERR_*, if PTR lookup failed. */
   } result_ptr;
+  /** @name Status fields
+   *
+   * These take one of the RES_STATUS_* values, depending on the state
+   * of the corresponding lookup.
+   *
+   * @{ */
   unsigned int res_status_ipv4 : 2;
   unsigned int res_status_ipv6 : 2;
   unsigned int res_status_hostname : 2;
-
+  /**@}*/
   uint8_t state; /**< Is this cached entry pending/done/informative? */
-  //uint8_t is_reverse; /**< Is this a reverse (addr-to-hostname) lookup? */
+
   time_t expire; /**< Remove items from cache after this time. */
   uint32_t ttl_ipv4; /**< What TTL did the nameserver tell us? */
   uint32_t ttl_ipv6; /**< What TTL did the nameserver tell us? */
@@ -201,9 +214,11 @@ static void assert_resolve_ok(cached_resolve_t *resolve);
 /** Hash table of cached_resolve objects. */
 static HT_HEAD(cache_map, cached_resolve_t) cache_root;
 
-/*DOCDOC*/
+/** Global: how many IPv6 requests have we made in all? */
 static uint64_t n_ipv6_requests_made = 0;
+/** Global: how many IPv6 requests have timed out? */
 static uint64_t n_ipv6_timeouts = 0;
+/** Global: Do we think that IPv6 DNS is broken? */
 static int dns_is_broken_for_ipv6 = 0;
 
 /** Function to compare hashed resolves on their addresses; used to
@@ -445,7 +460,7 @@ cached_resolve_add_answer(cached_resolve_t *resolve,
   }
 }
 
-/*DOCDOC*/
+/** Return true iff there are no in-flight requests for <b>resolve</b>. */
 static int
 cached_resolve_have_all_answers(const cached_resolve_t *resolve)
 {
@@ -911,7 +926,16 @@ dns_resolve_impl(edge_connection_t *exitconn, int is_resolve,
   return launch_resolve(resolve);
 }
 
-/* DOCDOC must set address_ttl, addr, etc.*/
+/** Given an exit connection <b>exitconn</b>, and a cached_resolve_t
+ * <b>resolve</b> whose DNS lookups have all succeeded or failed, update the
+ * appropriate fields (address_ttl and addr) of <b>exitconn</b>.
+ *
+ * If this is a reverse lookup, set *<b>hostname_out</b> to a newly allocated
+ * copy of the name resulting hostname.
+ *
+ * Return -2 on a transient error, -1 on a permenent error, and 1 on
+ * a successful lookup.
+ */
 static int
 set_exitconn_info_from_resolve(edge_connection_t *exitconn,
                                const cached_resolve_t *resolve,
@@ -1178,11 +1202,14 @@ is_test_address(const char *address)
     smartlist_string_isin_case(options->ServerDNSTestAddresses, address);
 }
 
-/** Called on the OR side when a DNS worker or the eventdns library tells us
- * the outcome of a DNS resolve: tell all pending connections about the result
- * of the lookup, and cache the value.  (<b>address</b> is a NUL-terminated
- * string containing the address to look up; <b>addr</b> is an IPv4 address in
- * host order; DOCDOC
+/** Called on the OR side when the eventdns library tells us the outcome of a
+ * single DNS resolve: remember the answer, and tell all pending connections
+ * about the result of the lookup if the lookup is now done.  (<b>address</b>
+ * is a NUL-terminated string containing the address to look up;
+ * <b>query_type</b> is one of DNS_{IPv4_A,IPv6_AAAA,PTR}; <b>dns_answer</b>
+ * is DNS_OK or one of DNS_ERR_*, <b>addr</b> is an IPv4 or IPv6 address if we
+ * got one; <b>hostname</b> is a hostname fora PTR request if we got one, and
+ * <b>ttl</b> is the time-to-live of this answer, in seconds.)
  */
 static void
 dns_found_answer(const char *address, uint8_t query_type,
@@ -1229,7 +1256,9 @@ dns_found_answer(const char *address, uint8_t query_type,
   }
 }
 
-/*DOCDOC*/
+/** Given a pending cached_resolve_t that we just finished resolving,
+ * inform every connection that was waiting for the outcome of that
+ * resolution. */
 static void
 inform_pending_connections(cached_resolve_t *resolve)
 {
@@ -1306,7 +1335,12 @@ inform_pending_connections(cached_resolve_t *resolve)
   }
 }
 
-/*DOCDOC*/
+/** Remove a pending cached_resolve_t from the hashtable, and add a
+ * corresponding cached cached_resolve_t.
+ *
+ * This function is only necessary because of the perversity of our
+ * cache timeout code; see inline comment for ideas on eliminating it.
+ **/
 static void
 make_pending_resolve_cached(cached_resolve_t *resolve)
 {
@@ -1627,7 +1661,9 @@ evdns_callback(int result, char type, int count, int ttl, void *addresses,
   tor_free(arg_);
 }
 
-/**DOCDOC*/
+/** Start a single DNS resolve for <b>address</b> (if <b>query_type</b> is
+ * DNS_IPv4_A or DNS_IPv6_AAAA) <b>ptr_address</b> (if <b>query_type</b> is
+ * DNS_PTR). Return 0 if we launched the request, -1 otherwise. */
 static int
 launch_one_resolve(const char *address, uint8_t query_type,
                    const tor_addr_t *ptr_address)
@@ -2011,7 +2047,7 @@ dns_seems_to_be_broken(void)
   return dns_is_completely_invalid;
 }
 
-/** DOCDOC */
+/** Return true iff we think that IPv6 hostname lookup is broken */
 int
 dns_seems_to_be_broken_for_ipv6(void)
 {

src/or/or.h

@@ -1237,7 +1237,6 @@ typedef struct listener_connection_t {
    * addresses? */
   unsigned int socks_prefer_ipv6 : 1;
 
-
 } listener_connection_t;
 
 /** Minimum length of the random part of an AUTH_CHALLENGE cell. */
@@ -1444,7 +1443,7 @@ typedef struct edge_connection_t {
 
   /** True iff this connection is for a DNS request only. */
   unsigned int is_dns_request:1;
-  /* DOCDOC exit only */
+  /** True iff this connection is for a PTR DNS request. (exit only) */
   unsigned int is_reverse_dns_lookup:1;
 
   unsigned int edge_has_sent_end:1; /**< For debugging; only used on edge
@@ -3772,7 +3771,7 @@ typedef struct {
   int PathBiasScaleFactor;
   /** @} */
 
-  int IPv6Exit; /**< DOCDOC*/
+  int IPv6Exit; /**< Do we support exiting to IPv6 addresses? */
 
 } or_options_t;