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Commit df3687ff authored by Florent Fourcot's avatar Florent Fourcot Committed by David S. Miller
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ipv6: add the IPV6_FL_F_REFLECT flag to IPV6_FL_A_GET 



With this option, the socket will reply with the flow label value read
on received packets.

The goal is to have a connection with the same flow label in both
direction of the communication.

Changelog of V4:
 * Do not erase the flow label on the listening socket. Use pktopts to
 store the received value

Signed-off-by: default avatarFlorent Fourcot <florent.fourcot@enst-bretagne.fr>
Acked-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3acfa1e7

include/linux/ipv6.h

+1 −0
Original line number Diff line number Diff line
@@ -191,6 +191,7 @@ struct ipv6_pinfo { 
	/* sockopt flags */

	__u16			recverr:1,

	                        sndflow:1,

				repflow:1,

				pmtudisc:3,

				ipv6only:1,

				srcprefs:3,	/* 001: prefer temporary address

include/uapi/linux/in6.h

+1 −0
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ struct in6_flowlabel_req { 


#define IPV6_FL_F_CREATE	1

#define IPV6_FL_F_EXCL		2

#define IPV6_FL_F_REFLECT	4



#define IPV6_FL_S_NONE		0

#define IPV6_FL_S_EXCL		1

net/ipv6/ip6_flowlabel.c

+21 −0
Original line number Diff line number Diff line
@@ -486,6 +486,11 @@ int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq) 
	struct ipv6_pinfo *np = inet6_sk(sk);

	struct ipv6_fl_socklist *sfl;



	if (np->repflow) {

		freq->flr_label = np->flow_label;

		return 0;

	}



	rcu_read_lock_bh();



	for_each_sk_fl_rcu(np, sfl) {
@@ -527,6 +532,15 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) 


	switch (freq.flr_action) {

	case IPV6_FL_A_PUT:

		if (freq.flr_flags & IPV6_FL_F_REFLECT) {

			if (sk->sk_protocol != IPPROTO_TCP)

				return -ENOPROTOOPT;

			if (!np->repflow)

				return -ESRCH;

			np->flow_label = 0;

			np->repflow = 0;

			return 0;

		}

		spin_lock_bh(&ip6_sk_fl_lock);

		for (sflp = &np->ipv6_fl_list;

		     (sfl = rcu_dereference(*sflp))!=NULL;
@@ -567,6 +581,13 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) 
		return -ESRCH;



	case IPV6_FL_A_GET:

		if (freq.flr_flags & IPV6_FL_F_REFLECT) {

			if (sk->sk_protocol != IPPROTO_TCP)

				return -ENOPROTOOPT;

			np->repflow = 1;

			return 0;

		}



		if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)

			return -EINVAL;

net/ipv6/tcp_ipv6.c

+11 −1
Original line number Diff line number Diff line
@@ -483,6 +483,9 @@ static int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst, 
				    &ireq->ir_v6_rmt_addr);



		fl6->daddr = ireq->ir_v6_rmt_addr;

		if (np->repflow && (ireq->pktopts != NULL))

			fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));



		skb_set_queue_mapping(skb, queue_mapping);

		err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass);

		err = net_xmit_eval(err);
@@ -1018,7 +1021,8 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 
	if (!isn) {

		if (ipv6_opt_accepted(sk, skb) ||

		    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||

		    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {

		    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim ||

		    np->repflow) {

			atomic_inc(&skb->users);

			ireq->pktopts = skb;

		}
@@ -1143,6 +1147,8 @@ static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb, 
		newnp->mcast_oif   = inet6_iif(skb);

		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;

		newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));

		if (np->repflow)

			newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));



		/*

		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
@@ -1223,6 +1229,8 @@ static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb, 
	newnp->mcast_oif  = inet6_iif(skb);

	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;

	newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));

	if (np->repflow)

		newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));



	/* Clone native IPv6 options from listening socket (if any)
@@ -1434,6 +1442,8 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 
			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;

		if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)

			np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));

		if (np->repflow)

			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));

		if (ipv6_opt_accepted(sk, opt_skb)) {

			skb_set_owner_r(opt_skb, sk);

			opt_skb = xchg(&np->pktoptions, opt_skb);