Re: [RFC 1/3] tcp: randomize tcp timestamp offsets for each connection
From: Eric Dumazet <hidden>
Date: 2016-08-25 21:07:19
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
On Thu, 2016-08-25 at 22:31 +0200, Florian Westphal wrote:
Eric Dumazet [off-list ref] wrote:quoted
On Thu, 2016-08-18 at 14:48 +0200, Florian Westphal wrote: It seems tcp_v4_reqsk_send_ack() and tcp_v6_reqsk_send_ack() were not taken into account. See commit 20a2b49fc5385 changelog packetdrill test showing the possible issue if the TS sent on an ACK in SYN_RECV state is wrong.Thanks a lot Eric, I'll fix this.
I would try :
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 47683c798f57..c2bf284239f6 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c@@ -826,7 +826,7 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, tcp_v4_send_ack(sock_net(sk), skb, seq, tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd, - tcp_time_stamp, + tcp_time_stamp + tcp_rsk(req)->ts_off, req->ts_recent, 0, tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index ce029c090f94..6411aa378b1b 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c@@ -955,7 +955,8 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt, tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd, - tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if, + tcp_time_stamp + tcp_rsk(req)->ts_off, + req->ts_recent, sk->sk_bound_dev_if, tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0, 0); }