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[bpf-next,v3,07/16] udp: Extract helper for selecting socket from reuseport group

Message ID 20200702092416.11961-8-jakub@cloudflare.com
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series Run a BPF program on socket lookup | expand

Commit Message

Jakub Sitnicki July 2, 2020, 9:24 a.m. UTC
Prepare for calling into reuseport from __udp4_lib_lookup as well.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
 net/ipv4/udp.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)
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Patch

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 31530129f137..0d03e0277263 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -408,6 +408,25 @@  static u32 udp_ehashfn(const struct net *net, const __be32 laddr,
 			      udp_ehash_secret + net_hash_mix(net));
 }
 
+static inline 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));
+		/* Fall back to scoring if group has connections */
+		if (reuseport_has_conns(sk, false))
+			return NULL;
+	}
+	return reuse_sk;
+}
+
 /* called with rcu_read_lock() */
 static struct sock *udp4_lib_lookup2(struct net *net,
 				     __be32 saddr, __be16 sport,
@@ -418,7 +437,6 @@  static struct sock *udp4_lib_lookup2(struct net *net,
 {
 	struct sock *sk, *result;
 	int score, badness;
-	u32 hash = 0;
 
 	result = NULL;
 	badness = 0;
@@ -426,15 +444,11 @@  static struct sock *udp4_lib_lookup2(struct net *net,
 		score = compute_score(sk, net, saddr, sport,
 				      daddr, hnum, dif, sdif);
 		if (score > badness) {
-			if (sk->sk_reuseport &&
-			    sk->sk_state != TCP_ESTABLISHED) {
-				hash = udp_ehashfn(net, daddr, hnum,
-						   saddr, sport);
-				result = reuseport_select_sock(sk, hash, skb,
-							sizeof(struct udphdr));
-				if (result && !reuseport_has_conns(sk, false))
-					return result;
-			}
+			result = lookup_reuseport(net, sk, skb,
+						  saddr, sport, daddr, hnum);
+			if (result)
+				return result;
+
 			badness = score;
 			result = sk;
 		}