From: Wei Wang <weiwan@xxxxxxxxxx>
[ Upstream commit ba9e04a7ddf4f22a10e05bf9403db6b97743c7bf ]
Currently, in tcp_v4_reqsk_send_ack() and tcp_v4_send_reset(), we
echo the TOS value of the received packets in the response.
However, we do not want to echo the lower 2 ECN bits in accordance
with RFC 3168 6.1.5 robustness principles.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Wei Wang <weiwan@xxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/ip_output.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -74,6 +74,7 @@
#include <net/icmp.h>
#include <net/checksum.h>
#include <net/inetpeer.h>
+#include <net/inet_ecn.h>
#include <net/lwtunnel.h>
#include <linux/bpf-cgroup.h>
#include <linux/igmp.h>
@@ -1697,7 +1698,7 @@ void ip_send_unicast_reply(struct sock *
if (IS_ERR(rt))
return;
- inet_sk(sk)->tos = arg->tos;
+ inet_sk(sk)->tos = arg->tos & ~INET_ECN_MASK;
sk->sk_protocol = ip_hdr(skb)->protocol;
sk->sk_bound_dev_if = arg->bound_dev_if;
