On Thu, Jan 26, 2017 at 10:02:40AM -0800, Eric Dumazet wrote:
> On Thu, 2017-01-26 at 17:37 +0100, Pablo Neira Ayuso wrote:
> > From: Pau Espin Pedrol <pespin.shar@xxxxxxxxx>
> >
> > Otherwise, RST packets generated by the TCP stack for non-existing
> > sockets always have mark 0.
> > The mark from the original packet is assigned to the netns_ipv4/6
> > socket used to send the response so that it can get copied into the
> > response skb when the socket sends it.
> >
> > Fixes: e110861f8609 ("net: add a sysctl to reflect the fwmark on replies")
> > Cc: Lorenzo Colitti <lorenzo@xxxxxxxxxx>
> > Signed-off-by: Pau Espin Pedrol <pau.espin@xxxxxxxxxxxx>
> > Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> > ---
> > net/ipv4/ip_output.c | 1 +
> > net/ipv6/tcp_ipv6.c | 1 +
> > 2 files changed, 2 insertions(+)
> >
> > diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
> > index fac275c48108..b67719f45953 100644
> > --- a/net/ipv4/ip_output.c
> > +++ b/net/ipv4/ip_output.c
> > @@ -1629,6 +1629,7 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
> > sk->sk_protocol = ip_hdr(skb)->protocol;
> > sk->sk_bound_dev_if = arg->bound_dev_if;
> > sk->sk_sndbuf = sysctl_wmem_default;
> > + sk->sk_mark = fl4.flowi4_mark;
> > err = ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base,
> > len, 0, &ipc, &rt, MSG_DONTWAIT);
> > if (unlikely(err)) {
> > diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
> > index 73bc8fc68acd..2b20622a5824 100644
> > --- a/net/ipv6/tcp_ipv6.c
> > +++ b/net/ipv6/tcp_ipv6.c
> > @@ -840,6 +840,7 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
> > dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
> > if (!IS_ERR(dst)) {
> > skb_dst_set(buff, dst);
> > + ctl_sk->sk_mark = fl6.flowi6_mark;
> > ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
> > TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
> > if (rst)
>
>
> This patch is wrong.
>
> ctl_sk is a shared socket, and tcp_v6_send_response() can be called from
> many different cpus at the same time.
Right. This is not percpu as in IPv4.
I can send a follow up patch to get this in sync with the way we do it
in IPv4, ie. add percpu socket.
Fine with this approach? Thanks!
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