inet: Extract helper for selecting socket from reuseport group

Prepare for calling into reuseport from __inet_lookup_listener 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/20200717103536.397595-4-jakub@cloudflare.com

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 2bbaaf0c717634502aa64098d1f4581b3eb1207d..ab64834837c84c53b256cdd63fcd21b5004187f4 100644 (file)
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -246,6 +246,21 @@ static inline int compute_score(struct sock *sk, struct net *net,
        return score;
 }
 
+static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk,
+                                           struct sk_buff *skb, int doff,
+                                           __be32 saddr, __be16 sport,
+                                           __be32 daddr, unsigned short hnum)
+{
+       struct sock *reuse_sk = NULL;
+       u32 phash;
+
+       if (sk->sk_reuseport) {
+               phash = inet_ehashfn(net, daddr, hnum, saddr, sport);
+               reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
+       }
+       return reuse_sk;
+}
+
 /*
  * Here are some nice properties to exploit here. The BSD API
  * does not allow a listening sock to specify the remote port nor the
@@ -265,21 +280,17 @@ static struct sock *inet_lhash2_lookup(struct net *net,
        struct inet_connection_sock *icsk;
        struct sock *sk, *result = NULL;
        int score, hiscore = 0;
-       u32 phash = 0;
 
        inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
                sk = (struct sock *)icsk;
                score = compute_score(sk, net, hnum, daddr,
                                      dif, sdif, exact_dif);
                if (score > hiscore) {
-                       if (sk->sk_reuseport) {
-                               phash = inet_ehashfn(net, daddr, hnum,
-                                                    saddr, sport);
-                               result = reuseport_select_sock(sk, phash,
-                                                              skb, doff);
-                               if (result)
-                                       return result;
-                       }
+                       result = lookup_reuseport(net, sk, skb, doff,
+                                                 saddr, sport, daddr, hnum);
+                       if (result)
+                               return result;
+
                        result = sk;
                        hiscore = score;
                }