From: Wei Wang weiwan@google.com
[ 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@google.com Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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;