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Commit 00483690 authored by Jon Maxwell's avatar Jon Maxwell Committed by David S. Miller
Browse files

tcp: Add mark for TIMEWAIT sockets 



This version has some suggestions by Eric Dumazet:

- Use a local variable for the mark in IPv6 instead of ctl_sk to avoid SMP
races.
- Use the more elegant "IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark"
statement.
- Factorize code as sk_fullsock() check is not necessary.

Aidan McGurn from Openwave Mobility systems reported the following bug:

"Marked routing is broken on customer deployment. Its effects are large
increase in Uplink retransmissions caused by the client never receiving
the final ACK to their FINACK - this ACK misses the mark and routes out
of the incorrect route."

Currently marks are added to sk_buffs for replies when the "fwmark_reflect"
sysctl is enabled. But not for TW sockets that had sk->sk_mark set via
setsockopt(SO_MARK..).

Fix this in IPv4/v6 by adding tw->tw_mark for TIME_WAIT sockets. Copy the the
original sk->sk_mark in __inet_twsk_hashdance() to the new tw->tw_mark location.
Then progate this so that the skb gets sent with the correct mark. Do the same
for resets. Give the "fwmark_reflect" sysctl precedence over sk->sk_mark so that
netfilter rules are still honored.

Signed-off-by: default avatarJon Maxwell <jmaxwell37@gmail.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 03bdfc00

include/net/inet_timewait_sock.h

+1 −0
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct inet_timewait_sock { 
#define tw_dr			__tw_common.skc_tw_dr



	int			tw_timeout;

	__u32			tw_mark;

	volatile unsigned char	tw_substate;

	unsigned char		tw_rcv_wscale;

net/ipv4/ip_output.c

+1 −1
Original line number Diff line number Diff line
@@ -1561,7 +1561,7 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, 
		oif = skb->skb_iif;



	flowi4_init_output(&fl4, oif,

			   IP4_REPLY_MARK(net, skb->mark),

			   IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark,

			   RT_TOS(arg->tos),

			   RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,

			   ip_reply_arg_flowi_flags(arg),

net/ipv4/tcp_ipv4.c

+14 −2
Original line number Diff line number Diff line
@@ -621,6 +621,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) 
	struct sock *sk1 = NULL;

#endif

	struct net *net;

	struct sock *ctl_sk;



	/* Never send a reset in response to a reset. */

	if (th->rst)
@@ -723,11 +724,16 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) 
	arg.tos = ip_hdr(skb)->tos;

	arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);

	local_bh_disable();

	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),

	ctl_sk = *this_cpu_ptr(net->ipv4.tcp_sk);

	if (sk)

		ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?

				   inet_twsk(sk)->tw_mark : sk->sk_mark;

	ip_send_unicast_reply(ctl_sk,

			      skb, &TCP_SKB_CB(skb)->header.h4.opt,

			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,

			      &arg, arg.iov[0].iov_len);



	ctl_sk->sk_mark = 0;

	__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);

	__TCP_INC_STATS(net, TCP_MIB_OUTRSTS);

	local_bh_enable();
@@ -759,6 +765,7 @@ static void tcp_v4_send_ack(const struct sock *sk, 
	} rep;

	struct net *net = sock_net(sk);

	struct ip_reply_arg arg;

	struct sock *ctl_sk;



	memset(&rep.th, 0, sizeof(struct tcphdr));

	memset(&arg, 0, sizeof(arg));
@@ -809,11 +816,16 @@ static void tcp_v4_send_ack(const struct sock *sk, 
	arg.tos = tos;

	arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);

	local_bh_disable();

	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),

	ctl_sk = *this_cpu_ptr(net->ipv4.tcp_sk);

	if (sk)

		ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?

				   inet_twsk(sk)->tw_mark : sk->sk_mark;

	ip_send_unicast_reply(ctl_sk,

			      skb, &TCP_SKB_CB(skb)->header.h4.opt,

			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,

			      &arg, arg.iov[0].iov_len);



	ctl_sk->sk_mark = 0;

	__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);

	local_bh_enable();

}

net/ipv4/tcp_minisocks.c

+1 −0
Original line number Diff line number Diff line
@@ -263,6 +263,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) 
		struct inet_sock *inet = inet_sk(sk);



		tw->tw_transparent	= inet->transparent;

		tw->tw_mark		= sk->sk_mark;

		tw->tw_rcv_wscale	= tp->rx_opt.rcv_wscale;

		tcptw->tw_rcv_nxt	= tp->rcv_nxt;

		tcptw->tw_snd_nxt	= tp->snd_nxt;

net/ipv6/tcp_ipv6.c

+5 −1
Original line number Diff line number Diff line
@@ -803,6 +803,7 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 
	unsigned int tot_len = sizeof(struct tcphdr);

	struct dst_entry *dst;

	__be32 *topt;

	__u32 mark = 0;



	if (tsecr)

		tot_len += TCPOLEN_TSTAMP_ALIGNED;
@@ -871,7 +872,10 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 
		fl6.flowi6_oif = oif;

	}



	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);

	if (sk)

		mark = (sk->sk_state == TCP_TIME_WAIT) ?

			inet_twsk(sk)->tw_mark : sk->sk_mark;

	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark;

	fl6.fl6_dport = t1->dest;

	fl6.fl6_sport = t1->source;

	fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);