[PATCH 6.6 056/175] tcp: Use bhash2 for v4-mapped-v6 non-wildcard address.

Greg Kroah-Hartman
2026-03-31T16:26:01Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit 5e07e672412bed473122813ab35d4f7d42fd9635 ]

While checking port availability in bind() or listen(), we used only
bhash for all v4-mapped-v6 addresses. But there is no good reason not
to use bhash2 for v4-mapped-v6 non-wildcard addresses.

Let's do it by returning true in inet_use_bhash2_on_bind(). Then, we
also need to add a test in inet_bind2_bucket_match_addr_any() so that
::ffff:X.X.X.X will match with 0.0.0.0.

Note that sk->sk_rcv_saddr is initialised for v4-mapped-v6 sk in
__inet6_bind().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: e537dd15d0d4 ("udp: Fix wildcard bind conflict check when using hash2")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv4/inet_connection_sock.c | 7 +++++--
net/ipv4/inet_hashtables.c | 3 ++-
2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index bd032ac2376ed..4a53c538dcaa1 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -157,8 +157,11 @@ static bool inet_use_bhash2_on_bind(const struct sock *sk)
if (sk->sk_family == AF_INET6) {
int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);

- return addr_type != IPV6_ADDR_ANY &&
- addr_type != IPV6_ADDR_MAPPED;
+ if (addr_type == IPV6_ADDR_ANY)
+ return false;
+
+ if (addr_type != IPV6_ADDR_MAPPED)
+ return true;
}
#endif
return sk->sk_rcv_saddr != htonl(INADDR_ANY);
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 7292f70176251..ed253aa1f5d3f 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -845,7 +845,8 @@ bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb, const
return ipv6_addr_any(&tb->v6_rcv_saddr) ||
ipv6_addr_v4mapped_any(&tb->v6_rcv_saddr);

- return false;
+ return ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr) &&
+ tb->rcv_saddr == 0;
}

if (sk->sk_family == AF_INET6)
--
2.51.0