From 25f1d1a84f459fe197508b07fc7cdb858d7468ee Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 16 May 2023 10:36:11 +1000 Subject: [PATCH] tap: Don't update ip6.addr_seen to :: When we receive packets from the tap side, we update the addr_seen fields to reflect the last known address of the guest or ns. For ip4.addr_seen we, sensibly, only update if the address we've just seen isn't 0 (0.0.0.0). This case can occur during early DHCP transactions. We have no equivalent case for IPv6. We're less likely to hit this, because DHCPv6 uses link-local addresses, however we can see an source address of :: with certain multicast operations. This can bite us if we try to make an incoming connection very early after starting pasta with --config-net: we may have only seen some of those multicast packets, updated addr_seen to :: and not had any "real" packets to update it to a global address. I've seen this with some of the avocado test conversions. In any case, it can never make sense to update addr_seen to ::, so explicitly exclude that case. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tap.c b/tap.c index faa4e26..c0b7f33 100644 --- a/tap.c +++ b/tap.c @@ -739,7 +739,7 @@ resume: if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr_seen)) { c->ip6.addr_seen = *saddr; } - } else { + } else if (!IN6_IS_ADDR_UNSPECIFIED(saddr)){ c->ip6.addr_seen = *saddr; }