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tcp: Move skb_steal_sock() to request_sock.h

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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>
This commit is contained in:
Kuniyuki Iwashima 2024-01-15 12:55:10 -08:00 committed by Alexei Starovoitov
parent b18afb6f42
commit 95e752b529
2 changed files with 28 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
include/net/request_sock.h
View File

@ -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)

25
include/net/sock.h
View File

@ -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.