commit a5538a36037641e49ca05aa3e90fec256794412b Author: David Goulet <dgoulet@torproject.org> Date: Fri Sep 18 12:22:23 2020 -0400 relay: Look at our cache when looking for an IP change Regularly, tor looks if its IP has changed. It does the entire auto discovery process again. However, it is possible that it does not find anything. Instead of thinking the IP changed to an unknown address, look at our cache and see if that value has changed. The reason for this is because if tor gets its address as a suggestion from a directory authority, it is because the auto discovery failed and thus that address should be consider for the IP change check. Related to #40071 Signed-off-by: David Goulet <dgoulet@torproject.org> --- src/feature/relay/router.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/src/feature/relay/router.c b/src/feature/relay/router.c index 29103ed6c6..259c38f162 100644 --- a/src/feature/relay/router.c +++ b/src/feature/relay/router.c @@ -2679,8 +2679,21 @@ check_descriptor_ipaddress_changed(time_t now) /* Ignore returned value because we want to notice not only an address * change but also if an address is lost (current == UNSPEC). */ - find_my_address(get_options(), family, LOG_INFO, ¤t, &method, - &hostname); + bool found = find_my_address(get_options(), family, LOG_INFO, ¤t, + &method, &hostname); + if (!found) { + /* Address was possibly not found because it is simply not configured or + * discoverable. Fallback to our cache, which includes any suggestion + * sent by a trusted directory server. */ + found = relay_find_addr_to_publish(get_options(), family, + RELAY_FIND_ADDR_CACHE_ONLY, + ¤t); + } + + /* The "current" address might be UNSPEC meaning it was not discovered nor + * found in our current cache. If we had an address before and we have + * none now, we consider this an IP change since it appears the relay lost + * its address. */ if (!tor_addr_eq(previous, ¤t)) { char *source;