Re: [PATCH v3 bpf-next 10/11] bpf: tcp: Support arbitrary SYN Cookie.

On 11/22/23 4:31 PM, Kuniyuki Iwashima wrote:

From: Martin KaFai Lau <martin.lau@linux.dev>
Date: Wed, 22 Nov 2023 15:19:29 -0800

quoted

On 11/21/23 10:42 AM, Kuniyuki Iwashima wrote:

quoted

diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index 533a7337865a..9a67f47a5e64 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h

@@ -116,9 +116,23 @@ struct sock *inet6_steal_sock(struct net *net, struct sk_buff *skb, int doff,
   	if (!sk)
   		return NULL;
   
-	if (!prefetched || !sk_fullsock(sk))
+	if (!prefetched)
   		return sk;
   
+	if (sk->sk_state == TCP_NEW_SYN_RECV) {
+#if IS_ENABLED(CONFIG_SYN_COOKIE)
+		if (inet_reqsk(sk)->syncookie) {
+			*refcounted = false;
+			skb->sk = sk;
+			skb->destructor = sock_pfree;

Instead of re-init the skb->sk and skb->destructor, can skb_steal_sock() avoid
resetting them to NULL in the first place and skb_steal_sock() returns the
rsk_listener instead?

Yes, but we need to move skb_steal_sock() to request_sock.h or include it just

Moving it seems better than including a header in the middle. Not sure if 
inet_sock.h or request_sock.h is a better target.

before skb_steal_sock() in sock.h like below.  When I include request_sock.h in
top of sock.h, there were many build errors.