tcp: TCP Fast Open Server - support TFO listeners
This patch builds on top of the previous patch to add the support
for TFO listeners. This includes -
1. allocating, properly initializing, and managing the per listener
fastopen_queue structure when TFO is enabled
2. changes to the inet_csk_accept code to support TFO. E.g., the
request_sock can no longer be freed upon accept(), not until 3WHS
finishes
3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg()
if it's a TFO socket
4. properly closing a TFO listener, and a TFO socket before 3WHS
finishes
5. supporting TCP_FASTOPEN socket option
6. modifying tcp_check_req() to use to check a TFO socket as well
as request_sock
7. supporting TCP's TFO cookie option
8. adding a new SYN-ACK retransmit handler to use the timer directly
off the TFO socket rather than the listener socket. Note that TFO
server side will not retransmit anything other than SYN-ACK until
the 3WHS is completed.
The patch also contains an important function
"reqsk_fastopen_remove()" to manage the somewhat complex relation
between a listener, its request_sock, and the corresponding child
socket. See the comment above the function for the detail.
Signed-off-by: H.K. Jerry Chu <[email protected]>
Cc: Yuchung Cheng <[email protected]>
Cc: Neal Cardwell <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Tom Herbert <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index f99b81d..09078b9 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -475,7 +475,7 @@
if (!dst && (dst = inet6_csk_route_req(sk, fl6, req)) == NULL)
goto done;
- skb = tcp_make_synack(sk, dst, req, rvp);
+ skb = tcp_make_synack(sk, dst, req, rvp, NULL);
if (skb) {
__tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
@@ -987,7 +987,7 @@
&ipv6_hdr(skb)->saddr,
&ipv6_hdr(skb)->daddr, inet6_iif(skb));
if (req)
- return tcp_check_req(sk, skb, req, prev);
+ return tcp_check_req(sk, skb, req, prev, false);
nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
&ipv6_hdr(skb)->saddr, th->source,
@@ -1179,6 +1179,7 @@
want_cookie)
goto drop_and_free;
+ tcp_rsk(req)->listener = NULL;
inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
return 0;
