syncookies: add support for ECN
Allows use of ECN when syncookies are in effect by encoding ecn_ok
into the syn-ack tcp timestamp.
While at it, remove a uneeded #ifdef CONFIG_SYN_COOKIES.
With CONFIG_SYN_COOKIES=nm want_cookie is ifdef'd to 0 and gcc
removes the "if (0)".
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 84d818c..09fd34f 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -164,6 +164,7 @@
int mss;
struct dst_entry *dst;
__u8 rcv_wscale;
+ bool ecn_ok;
if (!sysctl_tcp_syncookies || !th->ack || th->rst)
goto out;
@@ -180,7 +181,7 @@
memset(&tcp_opt, 0, sizeof(tcp_opt));
tcp_parse_options(skb, &tcp_opt, &hash_location, 0);
- if (!cookie_check_timestamp(&tcp_opt))
+ if (!cookie_check_timestamp(&tcp_opt, &ecn_ok))
goto out;
ret = NULL;
@@ -215,7 +216,7 @@
req->expires = 0UL;
req->retrans = 0;
- ireq->ecn_ok = 0;
+ ireq->ecn_ok = ecn_ok;
ireq->snd_wscale = tcp_opt.snd_wscale;
ireq->sack_ok = tcp_opt.sack_ok;
ireq->wscale_ok = tcp_opt.wscale_ok;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index f875345..5ebc27e 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1269,7 +1269,7 @@
treq = inet6_rsk(req);
ipv6_addr_copy(&treq->rmt_addr, &ipv6_hdr(skb)->saddr);
ipv6_addr_copy(&treq->loc_addr, &ipv6_hdr(skb)->daddr);
- if (!want_cookie)
+ if (!want_cookie || tmp_opt.tstamp_ok)
TCP_ECN_create_request(req, tcp_hdr(skb));
if (!isn) {