From: Jakub Sitnicki <jakub@cloudflare.com>
Date: Fri, 17 Jul 2020 12:35:28 +0200
Subject: udp: Extract helper for selecting socket from reuseport group
Patch-mainline: v5.9-rc1
Git-commit: 7629c73a1466ec2348e9f64c874c19bf13f35f4c
References: bsc#1177028
Prepare for calling into reuseport from __udp4_lib_lookup as well.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200717103536.397595-8-jakub@cloudflare.com
Acked-by: Gary Lin <glin@suse.com>
NOTE from Gary:
The original commit conflicts with a 5.8-rc7 fix(*1). Follow the merge commit
to modify this patch.
(*1) efc6b6f6c3113 udp: Improve load balancing for SO_REUSEPORT.
(*2) a57066b1a0197 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
---
net/ipv4/udp.c | 37 +++++++++++++++++++++++--------------
1 file changed, 23 insertions(+), 14 deletions(-)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -408,6 +408,22 @@ static u32 udp_ehashfn(const struct net
udp_ehash_secret + net_hash_mix(net));
}
+static struct sock *lookup_reuseport(struct net *net, struct sock *sk,
+ struct sk_buff *skb,
+ __be32 saddr, __be16 sport,
+ __be32 daddr, unsigned short hnum)
+{
+ struct sock *reuse_sk = NULL;
+ u32 hash;
+
+ if (sk->sk_reuseport && sk->sk_state != TCP_ESTABLISHED) {
+ hash = udp_ehashfn(net, daddr, hnum, saddr, sport);
+ reuse_sk = reuseport_select_sock(sk, hash, skb,
+ sizeof(struct udphdr));
+ }
+ return reuse_sk;
+}
+
/* called with rcu_read_lock() */
static struct sock *udp4_lib_lookup2(struct net *net,
__be32 saddr, __be16 sport,
@@ -416,9 +432,8 @@ static struct sock *udp4_lib_lookup2(str
struct udp_hslot *hslot2,
struct sk_buff *skb)
{
- struct sock *sk, *result, *reuseport_result;
+ struct sock *sk, *result;
int score, badness;
- u32 hash = 0;
result = NULL;
badness = 0;
@@ -426,19 +441,13 @@ static struct sock *udp4_lib_lookup2(str
score = compute_score(sk, net, saddr, sport,
daddr, hnum, dif, sdif);
if (score > badness) {
- reuseport_result = NULL;
-
- if (sk->sk_reuseport &&
- sk->sk_state != TCP_ESTABLISHED) {
- hash = udp_ehashfn(net, daddr, hnum,
- saddr, sport);
- reuseport_result = reuseport_select_sock(sk, hash, skb,
- sizeof(struct udphdr));
- if (reuseport_result && !reuseport_has_conns(sk, false))
- return reuseport_result;
- }
+ result = lookup_reuseport(net, sk, skb,
+ saddr, sport, daddr, hnum);
+ /* Fall back to scoring if group has connections */
+ if (result && !reuseport_has_conns(sk, false))
+ return result;
- result = reuseport_result ? : sk;
+ result = result ? : sk;
badness = score;
}
}