tcp: Move skb_steal_sock() to request_sock.h

We will support arbitrary SYN Cookie with BPF.

If BPF prog validates ACK and kfunc allocates a reqsk, it will
be carried to TCP stack as skb->sk with req->syncookie 1.

In skb_steal_sock(), we need to check inet_reqsk(sk)->syncookie
to see if the reqsk is created by kfunc.  However, inet_reqsk()
is not available in sock.h.

Let's move skb_steal_sock() to request_sock.h.

While at it, we refactor skb_steal_sock() so it returns early if
skb->sk is NULL to minimise the following patch.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240115205514.68364-3-kuniyu@amazon.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index 144c39db9898abcf8cc8582597d04a912ef53495..26c630c40abb15714af6c0b7d3999a3c714b5b88 100644 (file)
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -83,6 +83,34 @@ static inline struct sock *req_to_sk(struct request_sock *req)
        return (struct sock *)req;
 }
 
+/**
+ * skb_steal_sock - steal a socket from an sk_buff
+ * @skb: sk_buff to steal the socket from
+ * @refcounted: is set to true if the socket is reference-counted
+ * @prefetched: is set to true if the socket was assigned from bpf
+ */
+static inline struct sock *skb_steal_sock(struct sk_buff *skb,
+                                         bool *refcounted, bool *prefetched)
+{
+       struct sock *sk = skb->sk;
+
+       if (!sk) {
+               *prefetched = false;
+               *refcounted = false;
+               return NULL;
+       }
+
+       *prefetched = skb_sk_is_prefetched(skb);
+       if (*prefetched)
+               *refcounted = sk_is_refcounted(sk);
+       else
+               *refcounted = true;
+
+       skb->destructor = NULL;
+       skb->sk = NULL;
+       return sk;
+}
+
 static inline struct request_sock *
 reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
            bool attach_listener)

diff --git a/include/net/sock.h b/include/net/sock.h
index a7f815c7cfdfdf1296be2967fd100efdb10cdd63..32a399fdcbb5963b40cbc1392ee0eb14ada51865 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2814,31 +2814,6 @@ sk_is_refcounted(struct sock *sk)
        return !sk_fullsock(sk) || !sock_flag(sk, SOCK_RCU_FREE);
 }
 
-/**
- * skb_steal_sock - steal a socket from an sk_buff
- * @skb: sk_buff to steal the socket from
- * @refcounted: is set to true if the socket is reference-counted
- * @prefetched: is set to true if the socket was assigned from bpf
- */
-static inline struct sock *
-skb_steal_sock(struct sk_buff *skb, bool *refcounted, bool *prefetched)
-{
-       if (skb->sk) {
-               struct sock *sk = skb->sk;
-
-               *refcounted = true;
-               *prefetched = skb_sk_is_prefetched(skb);
-               if (*prefetched)
-                       *refcounted = sk_is_refcounted(sk);
-               skb->destructor = NULL;
-               skb->sk = NULL;
-               return sk;
-       }
-       *prefetched = false;
-       *refcounted = false;
-       return NULL;
-}
-
 /* Checks if this SKB belongs to an HW offloaded socket
  * and whether any SW fallbacks are required based on dev.
  * Check decrypted mark in case skb_orphan() cleared socket.