Merge branch 'bug23826-23828_squashed'

changes/bug23826-23828

@@ -0,0 +1,14 @@
+  o Major features (IPv6, directory documents):
+    - Add consensus method 27, which adds IPv6 ORPorts to the microdesc
+      consensus. This makes it easier for IPv6 clients to bootstrap and
+      choose reachable entry guards.
+      Implements 23826.
+    - Add consensus method 28, which removes IPv6 ORPorts from
+      microdescriptors. Now that there are IPv6 ORPorts in the microdesc
+      consensus, they are redundant in microdescs. This change is compatible
+      with tor clients on 0.2.8.x and later. (0.2.8.x introduced client IPv6
+      bootstrap and guard support.)
+      Implements 23828.
+    - Expand the documentation for AuthDirHasIPv6Connectivity when it is set
+      by different numbers of authorities.
+      Fixes 23870 on 0.2.4.1-alpha.

doc/tor.1.txt

@@ -2473,9 +2473,29 @@ on the public Tor network.
 
 [[AuthDirHasIPv6Connectivity]] **AuthDirHasIPv6Connectivity** **0**|**1**::
     Authoritative directories only. When set to 0, OR ports with an
-    IPv6 address are being accepted without reachability testing.
-    When set to 1, IPv6 OR ports are being tested just like IPv4 OR
-    ports. (Default: 0)
+    IPv6 address are not included in the authority's votes. When set to 1,
+    IPv6 OR ports are tested for reachability like IPv4 OR ports. If the
+    reachability test succeeds, the authority votes for the IPv6 ORPort, and
+    votes Running for the relay. If the reachability test fails, the authority
+    does not vote for the IPv6 ORPort, and does not vote Running (Default: 0)  +
++
+    The content of the consensus depends on the number of voting authorities
+    that set AuthDirHasIPv6Connectivity:
+
+      If no authorities set AuthDirHasIPv6Connectivity 1, there will be no
+      IPv6 ORPorts in the consensus.
+
+      If a minority of authorities set AuthDirHasIPv6Connectivity 1,
+      unreachable IPv6 ORPorts will be removed from the consensus. But the
+      majority of IPv4-only authorities will still vote the relay as Running.
+      Reachable IPv6 ORPort lines will be included in the consensus
+
+      If a majority of voting authorities set AuthDirHasIPv6Connectivity 1,
+      relays with unreachable IPv6 ORPorts will not be listed as Running.
+      Reachable IPv6 ORPort lines will be included in the consensus
+      (To ensure that any valid majority will vote relays with unreachable
+      IPv6 ORPorts not Running, 75% of authorities must set
+      AuthDirHasIPv6Connectivity 1.)
 
 [[MinMeasuredBWsForAuthToIgnoreAdvertised]] **MinMeasuredBWsForAuthToIgnoreAdvertised** __N__::
     A total value, in abstract bandwidth units, describing how much

src/or/dirserv.c

@@ -1903,21 +1903,28 @@ version_from_platform(const char *platform)
 /** Helper: write the router-status information in <b>rs</b> into a newly
  * allocated character buffer.  Use the same format as in network-status
  * documents.  If <b>version</b> is non-NULL, add a "v" line for the platform.
+ *
+ * consensus_method is the current consensus method when format is
+ * NS_V3_CONSENSUS or NS_V3_CONSENSUS_MICRODESC. It is ignored for other
+ * formats: pass ROUTERSTATUS_FORMAT_NO_CONSENSUS_METHOD.
+ *
  * Return 0 on success, -1 on failure.
  *
  * The format argument has one of the following values:
  *   NS_V2 - Output an entry suitable for a V2 NS opinion document
  *   NS_V3_CONSENSUS - Output the first portion of a V3 NS consensus entry
+ *        for consensus_method.
  *   NS_V3_CONSENSUS_MICRODESC - Output the first portion of a V3 microdesc
- *        consensus entry.
+ *        consensus entry for consensus_method.
  *   NS_V3_VOTE - Output a complete V3 NS vote. If <b>vrs</b> is present,
  *        it contains additional information for the vote.
- *   NS_CONTROL_PORT - Output a NS document for the control port
+ *   NS_CONTROL_PORT - Output a NS document for the control port.
  */
 char *
 routerstatus_format_entry(const routerstatus_t *rs, const char *version,
                           const char *protocols,
                           routerstatus_format_type_t format,
+                          int consensus_method,
                           const vote_routerstatus_t *vrs)
 {
   char *summary;
@@ -1948,8 +1955,10 @@ routerstatus_format_entry(const routerstatus_t *rs, const char *version,
    * networkstatus_type_t values, with an additional control port value
    * added -MP */
 
-  /* V3 microdesc consensuses don't have "a" lines. */
-  if (format == NS_V3_CONSENSUS_MICRODESC)
+  /* V3 microdesc consensuses only have "a" lines in later consensus methods
+   */
+  if (format == NS_V3_CONSENSUS_MICRODESC &&
+      consensus_method < MIN_METHOD_FOR_A_LINES_IN_MICRODESC_CONSENSUS)
     goto done;
 
   /* Possible "a" line. At most one for now. */
@@ -1958,7 +1967,7 @@ routerstatus_format_entry(const routerstatus_t *rs, const char *version,
                            fmt_addrport(&rs->ipv6_addr, rs->ipv6_orport));
   }
 
-  if (format == NS_V3_CONSENSUS)
+  if (format == NS_V3_CONSENSUS || format == NS_V3_CONSENSUS_MICRODESC)
     goto done;
 
   smartlist_add_asprintf(chunks,

src/or/dirserv.h

@@ -150,6 +150,7 @@ char *routerstatus_format_entry(
                               const char *version,
                               const char *protocols,
                               routerstatus_format_type_t format,
+                              int consensus_method,
                               const vote_routerstatus_t *vrs);
 void dirserv_free_all(void);
 void cached_dir_decref(cached_dir_t *d);

src/or/dirvote.c

@@ -278,7 +278,9 @@ format_networkstatus_vote(crypto_pk_t *private_signing_key,
     vote_microdesc_hash_t *h;
     rsf = routerstatus_format_entry(&vrs->status,
                                     vrs->version, vrs->protocols,
-                                    NS_V3_VOTE, vrs);
+                                    NS_V3_VOTE,
+                                    ROUTERSTATUS_FORMAT_NO_CONSENSUS_METHOD,
+                                    vrs);
     if (rsf)
       smartlist_add(chunks, rsf);
 
@@ -1317,8 +1319,9 @@ compute_nth_protocol_set(int n, int n_voters, const smartlist_t *votes)
 /** Given a list of vote networkstatus_t in <b>votes</b>, our public
  * authority <b>identity_key</b>, our private authority <b>signing_key</b>,
  * and the number of <b>total_authorities</b> that we believe exist in our
- * voting quorum, generate the text of a new v3 consensus vote, and return the
- * value in a newly allocated string.
+ * voting quorum, generate the text of a new v3 consensus or microdescriptor
+ * consensus (depending on <b>flavor</b>), and return the value in a newly
+ * allocated string.
  *
  * Note: this function DOES NOT check whether the votes are from
  * recognized authorities.   (dirvote_add_vote does that.)
@@ -2101,7 +2104,8 @@ networkstatus_compute_consensus(smartlist_t *votes,
         char *buf;
         /* Okay!! Now we can write the descriptor... */
         /*     First line goes into "buf". */
-        buf = routerstatus_format_entry(&rs_out, NULL, NULL, rs_format, NULL);
+        buf = routerstatus_format_entry(&rs_out, NULL, NULL,
+                                        rs_format, consensus_method, NULL);
         if (buf)
           smartlist_add(chunks, buf);
       }
@@ -3831,7 +3835,10 @@ dirvote_create_microdescriptor(const routerinfo_t *ri, int consensus_method)
     smartlist_add_asprintf(chunks, "ntor-onion-key %s", kbuf);
   }
 
+  /* We originally put a lines in the micrdescriptors, but then we worked out
+   * that we needed them in the microdesc consensus. See #20916. */
   if (consensus_method >= MIN_METHOD_FOR_A_LINES &&
+      consensus_method < MIN_METHOD_FOR_NO_A_LINES_IN_MICRODESC &&
       !tor_addr_is_null(&ri->ipv6_addr) && ri->ipv6_orport)
     smartlist_add_asprintf(chunks, "a %s\n",
                            fmt_addrport(&ri->ipv6_addr, ri->ipv6_orport));
@@ -3940,7 +3947,9 @@ static const struct consensus_method_range_t {
   {MIN_METHOD_FOR_P6_LINES, MIN_METHOD_FOR_NTOR_KEY - 1},
   {MIN_METHOD_FOR_NTOR_KEY, MIN_METHOD_FOR_ID_HASH_IN_MD - 1},
   {MIN_METHOD_FOR_ID_HASH_IN_MD, MIN_METHOD_FOR_ED25519_ID_IN_MD - 1},
-  {MIN_METHOD_FOR_ED25519_ID_IN_MD, MAX_SUPPORTED_CONSENSUS_METHOD},
+  {MIN_METHOD_FOR_ED25519_ID_IN_MD,
+    MIN_METHOD_FOR_NO_A_LINES_IN_MICRODESC - 1},
+  {MIN_METHOD_FOR_NO_A_LINES_IN_MICRODESC, MAX_SUPPORTED_CONSENSUS_METHOD},
   {-1, -1}
 };
 

src/or/dirvote.h

@@ -51,11 +51,15 @@
 #define MIN_VOTE_INTERVAL_TESTING_INITIAL \
                 ((MIN_VOTE_SECONDS_TESTING)+(MIN_DIST_SECONDS_TESTING)+1)
 
+/* A placeholder for routerstatus_format_entry() when the consensus method
+ * argument is not applicable. */
+#define ROUTERSTATUS_FORMAT_NO_CONSENSUS_METHOD 0
+
 /** The lowest consensus method that we currently support. */
 #define MIN_SUPPORTED_CONSENSUS_METHOD 13
 
 /** The highest consensus method that we currently support. */
-#define MAX_SUPPORTED_CONSENSUS_METHOD 26
+#define MAX_SUPPORTED_CONSENSUS_METHOD 28
 
 /** Lowest consensus method where microdesc consensuses omit any entry
  * with no microdesc. */
@@ -115,6 +119,14 @@
  * instead of 0. See #14881 */
 #define MIN_METHOD_FOR_INIT_BW_WEIGHTS_ONE 26
 
+/** Lowest consensus method where the microdesc consensus contains relay IPv6
+ * addresses. See #23826 and #20916. */
+#define MIN_METHOD_FOR_A_LINES_IN_MICRODESC_CONSENSUS 27
+
+/** Lowest consensus method where microdescriptors do not contain relay IPv6
+ * addresses. See #23828 and #20916. */
+#define MIN_METHOD_FOR_NO_A_LINES_IN_MICRODESC 28
+
 /** Default bandwidth to clip unmeasured bandwidths to using method >=
  * MIN_METHOD_TO_CLIP_UNMEASURED_BW.  (This is not a consensus method; do not
  * get confused with the above macros.) */

src/or/networkstatus.c

@@ -2209,7 +2209,9 @@ signed_descs_update_status_from_consensus_networkstatus(smartlist_t *descs)
 char *
 networkstatus_getinfo_helper_single(const routerstatus_t *rs)
 {
-  return routerstatus_format_entry(rs, NULL, NULL, NS_CONTROL_PORT, NULL);
+  return routerstatus_format_entry(rs, NULL, NULL, NS_CONTROL_PORT,
+                                   ROUTERSTATUS_FORMAT_NO_CONSENSUS_METHOD,
+                                   NULL);
 }
 
 /** Alloc and return a string describing routerstatuses for the most