Re: [PATCH bpf-next v4 6/7] bpf, net: Support SO_REUSEPORT sockets with bpf_sk_assign

From: Lorenz Bauer lmb@isovalent.com Date: Wed, 28 Jun 2023 10:48:21 +0100

diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h index a6722d6ef80f..7d677b89f269 100644 --- a/include/net/inet6_hashtables.h +++ b/include/net/inet6_hashtables.h @@ -103,6 +103,46 @@ static inline struct sock *__inet6_lookup(struct net *net, daddr, hnum, dif, sdif); } +static inline +struct sock *inet6_steal_sock(struct net *net, struct sk_buff *skb, int doff,

• 	      const struct in6_addr *saddr, const __be16 sport,
  

• 	      const struct in6_addr *daddr, const __be16 dport,
  

• 	      bool *refcounted, inet6_ehashfn_t *ehashfn)
  

+{

• struct sock *sk, *reuse_sk;
• bool prefetched;
• sk = skb_steal_sock(skb, refcounted, &prefetched);
• if (!sk)

• return NULL;
  

• if (!prefetched)

• return sk;
  

• if (sk->sk_protocol == IPPROTO_TCP) {

• if (sk->sk_state != TCP_LISTEN)
  

• 	return sk;
  

• } else if (sk->sk_protocol == IPPROTO_UDP) {

• if (sk->sk_state != TCP_CLOSE)
  

• 	return sk;
  

• } else {

• return sk;
  

• }
• reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff,

• 			  saddr, sport, daddr, ntohs(dport),
  

• 			  ehashfn);
  

• if (!reuse_sk || reuse_sk == sk)

• return sk;
  

• /* We've chosen a new reuseport sock which is never refcounted. This

• * implies that sk also isn't refcounted.
  

• */
  

• WARN_ON_ONCE(*refcounted);

One more nit.

WARN_ON_ONCE() should be tested before inet6?_lookup_reuseport() not to miss the !reuse_sk case.

• return reuse_sk;

+}