| Message ID | 20201208175508.1793520-1-weiwan@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] tcp: Retain ECT bits for tos reflection | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net |
| netdev/subject_prefix | success | Link |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 17 this patch: 17 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 38 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 17 this patch: 17 |
| netdev/header_inline | success | Link |
| netdev/stable | success | Stable not CCed |
From: Wei Wang <weiwan@google.com> Date: Tue, 8 Dec 2020 09:55:08 -0800 > For DCTCP, we have to retain the ECT bits set by the congestion control > algorithm on the socket when reflecting syn TOS in syn-ack, in order to > make ECN work properly. > > Fixes: ac8f1710c12b ("tcp: reflect tos value received in SYN to the socket") > Reported-by: Alexander Duyck <alexanderduyck@fb.com> > Signed-off-by: Wei Wang <weiwan@google.com> > Reviewed-by: Eric Dumazet <edumazet@google.com> Applied, thanks.
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 8391aa29e7a4..595dcc3afac5 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -984,7 +984,8 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); tos = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ? - tcp_rsk(req)->syn_tos & ~INET_ECN_MASK : + (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) | + (inet_sk(sk)->tos & INET_ECN_MASK) : inet_sk(sk)->tos; if (!INET_ECN_is_capable(tos) && @@ -1541,7 +1542,9 @@ struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; newinet->inet_id = prandom_u32(); - /* Set ToS of the new socket based upon the value of incoming SYN. */ + /* Set ToS of the new socket based upon the value of incoming SYN. + * ECT bits are set later in tcp_init_transfer(). + */ if (sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 992cbf3eb9e3..f676f176eb6b 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -528,7 +528,8 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst, fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts)); tclass = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ? - tcp_rsk(req)->syn_tos & ~INET_ECN_MASK : + (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) | + (np->tclass & INET_ECN_MASK) : np->tclass; if (!INET_ECN_is_capable(tclass) && @@ -1320,7 +1321,9 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * if (np->repflow) newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb)); - /* Set ToS of the new socket based upon the value of incoming SYN. */ + /* Set ToS of the new socket based upon the value of incoming SYN. + * ECT bits are set later in tcp_init_transfer(). + */ if (sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) newnp->tclass = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
For DCTCP, we have to retain the ECT bits set by the congestion control algorithm on the socket when reflecting syn TOS in syn-ack, in order to make ECN work properly. Fixes: ac8f1710c12b ("tcp: reflect tos value received in SYN to the socket") Reported-by: Alexander Duyck <alexanderduyck@fb.com> Signed-off-by: Wei Wang <weiwan@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> --- net/ipv4/tcp_ipv4.c | 7 +++++-- net/ipv6/tcp_ipv6.c | 7 +++++-- 2 files changed, 10 insertions(+), 4 deletions(-)