[tor-commits] [tor/master] relay: Simplify IPv6 discovery when building descriptor

[nickm at torproject.org]

commit b4220a09b71a924e423798c4cf5001c0bdc07f89
Author: David Goulet <dgoulet at torproject.org>
Date:   Fri Jan 22 10:29:08 2021 -0500

    relay: Simplify IPv6 discovery when building descriptor
    
    Now that relay_find_addr_to_publish() checks if we actually have an ORPort, we
    can simplify the descriptor building phase for IPv6.
    
    This also avoid triggering an IPv6 discovery if the IPv4 can't be found in the
    first place.
    
    Related to #40254
    
    Signed-off-by: David Goulet <dgoulet at torproject.org>
---
 src/feature/relay/router.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/src/feature/relay/router.c b/src/feature/relay/router.c
index eb1d5a63f1..e5111acd65 100644
--- a/src/feature/relay/router.c
+++ b/src/feature/relay/router.c
@@ -2047,12 +2047,11 @@ MOCK_IMPL(STATIC int,
 router_build_fresh_unsigned_routerinfo,(routerinfo_t **ri_out))
 {
   routerinfo_t *ri = NULL;
-  tor_addr_t ipv4_addr, ipv6_addr;
+  tor_addr_t ipv4_addr;
   char platform[256];
   int hibernating = we_are_hibernating();
   const or_options_t *options = get_options();
   int result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
-  uint16_t ipv6_orport = 0;
 
   if (BUG(!ri_out)) {
     result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
@@ -2064,10 +2063,6 @@ router_build_fresh_unsigned_routerinfo,(routerinfo_t **ri_out))
   bool have_v4 = relay_find_addr_to_publish(options, AF_INET,
                                             RELAY_FIND_ADDR_NO_FLAG,
                                             &ipv4_addr);
-  bool have_v6 = relay_find_addr_to_publish(options, AF_INET6,
-                                            RELAY_FIND_ADDR_NO_FLAG,
-                                            &ipv6_addr);
-
   /* Tor requires a relay to have an IPv4 so bail if we can't find it. */
   if (!have_v4) {
     log_info(LD_CONFIG, "Don't know my address while generating descriptor. "
@@ -2079,24 +2074,21 @@ router_build_fresh_unsigned_routerinfo,(routerinfo_t **ri_out))
   /* Log a message if the address in the descriptor doesn't match the ORPort
    * and DirPort addresses configured by the operator. */
   router_check_descriptor_address_consistency(&ipv4_addr);
-  router_check_descriptor_address_consistency(&ipv6_addr);
 
   ri = tor_malloc_zero(sizeof(routerinfo_t));
+  tor_addr_copy(&ri->ipv4_addr, &ipv4_addr);
   ri->cache_info.routerlist_index = -1;
   ri->nickname = tor_strdup(options->Nickname);
 
   /* IPv4. */
-  tor_addr_copy(&ri->ipv4_addr, &ipv4_addr);
   ri->ipv4_orport = routerconf_find_or_port(options, AF_INET);
   ri->ipv4_dirport = routerconf_find_dir_port(options, 0);
 
-  /* IPv6. Do not publish an IPv6 if we don't have an ORPort that can be used
-   * with the address. This is possible for instance if the ORPort is
-   * IPv4Only. */
-  ipv6_orport = routerconf_find_or_port(options, AF_INET6);
-  if (have_v6 && ipv6_orport != 0) {
-    tor_addr_copy(&ri->ipv6_addr, &ipv6_addr);
-    ri->ipv6_orport = ipv6_orport;
+  /* Optionally check for an IPv6. We still publish without one. */
+  if (relay_find_addr_to_publish(options, AF_INET6, RELAY_FIND_ADDR_NO_FLAG,
+                                 &ri->ipv6_addr)) {
+    ri->ipv6_orport = routerconf_find_or_port(options, AF_INET6);
+    router_check_descriptor_address_consistency(&ri->ipv6_addr);
   }
 
   ri->supports_tunnelled_dir_requests =