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authorPetar Penkov <ppenkov@google.com>2019-07-29 09:59:14 -0700
committerAlexei Starovoitov <ast@kernel.org>2019-07-30 21:03:05 -0700
commit9349d600fb6a1ca0aaeb515523e1bb5409483d76 (patch)
tree214a3a4b68356a5977e75afe2117538810b64d10 /net/ipv4/tcp_ipv4.c
parent965112785e4bd4355262c6c5a32ea8f349adb401 (diff)
downloadlinux-9349d600fb6a1ca0aaeb515523e1bb5409483d76.tar.bz2
tcp: add skb-less helpers to retrieve SYN cookie
This patch allows generation of a SYN cookie before an SKB has been allocated, as is the case at XDP. Signed-off-by: Petar Penkov <ppenkov@google.com> Reviewed-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
-rw-r--r--net/ipv4/tcp_ipv4.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d57641cb3477..10217393cda6 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1515,6 +1515,21 @@ static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
return sk;
}
+u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
+ struct tcphdr *th, u32 *cookie)
+{
+ u16 mss = 0;
+#ifdef CONFIG_SYN_COOKIES
+ mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
+ &tcp_request_sock_ipv4_ops, sk, th);
+ if (mss) {
+ *cookie = __cookie_v4_init_sequence(iph, th, &mss);
+ tcp_synq_overflow(sk);
+ }
+#endif
+ return mss;
+}
+
/* The socket must have it's spinlock held when we get
* here, unless it is a TCP_LISTEN socket.
*