From: Jakub Sitnicki <jakub@cloudflare.com>
Date: Wed, 22 Jul 2020 18:17:19 +0200
Subject: udp: Don't discard reuseport selection when group has connections
Patch-mainline: v5.9-rc1
Git-commit: c8a2983c4df06c4cd11bea6abfa7e2947bd3113b
References: bsc#1177028

When BPF socket lookup prog selects a socket that belongs to a reuseport
group, and the reuseport group has connected sockets in it, the socket
selected by reuseport will be discarded, and socket returned by BPF socket
lookup will be used instead.

Modify this behavior so that the socket selected by reuseport running after
BPF socket lookup always gets used. Ignore the fact that the reuseport
group might have connections because it is only relevant when scoring
sockets during regular hashtable-based lookup.

Fixes: 72f7e9440e9b ("udp: Run SK_LOOKUP BPF program on socket lookup")
Fixes: 6d4201b1386b ("udp6: Run SK_LOOKUP BPF program on socket lookup")
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Link: https://lore.kernel.org/bpf/20200722161720.940831-2-jakub@cloudflare.com
Acked-by: Gary Lin <glin@suse.com>
---
 net/ipv6/udp.c |    3 ---
 1 file changed, 3 deletions(-)

--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -155,9 +155,6 @@ static inline struct sock *lookup_reusep
 		hash = udp6_ehashfn(net, daddr, hnum, saddr, sport);
 		reuse_sk = reuseport_select_sock(sk, hash, skb,
 						 sizeof(struct udphdr));
-		/* Fall back to scoring if group has connections */
-		if (reuseport_has_conns(sk, false))
-			return NULL;
 	}
 	return reuse_sk;
 }