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Commit ec01147a authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'tcp-flowlabel' 



Eric Dumazet says:

====================
ipv6: tcp: more control on RST flowlabels

First patch allows to reflect incoming IPv6 flowlabel
on RST packets sent when no socket could handle the packet.

Second patch makes sure we send the same flowlabel
for RST or ACK packets on behalf of TIME_WAIT sockets.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents e736bf72 50a8accf

Documentation/networking/ip-sysctl.txt

+15 −5
Original line number Diff line number Diff line
@@ -1429,14 +1429,24 @@ flowlabel_state_ranges - BOOLEAN 
	FALSE: disabled

	Default: true



flowlabel_reflect - BOOLEAN

	Automatically reflect the flow label. Needed for Path MTU

flowlabel_reflect - INTEGER

	Control flow label reflection. Needed for Path MTU

	Discovery to work with Equal Cost Multipath Routing in anycast

	environments. See RFC 7690 and:

	https://tools.ietf.org/html/draft-wang-6man-flow-label-reflection-01

	TRUE: enabled

	FALSE: disabled

	Default: FALSE



	This is a mask of two bits.

	1: enabled for established flows



	Note that this prevents automatic flowlabel changes, as done

	in "tcp: change IPv6 flow-label upon receiving spurious retransmission"

	and "tcp: Change txhash on every SYN and RTO retransmit"



	2: enabled for TCP RESET packets (no active listener)

	If set, a RST packet sent in response to a SYN packet on a closed

	port will reflect the incoming flow label.



	Default: 0



fib_multipath_hash_policy - INTEGER

	Controls which hash policy to use for multipath routes.

net/ipv6/af_inet6.c

+1 −1
Original line number Diff line number Diff line
@@ -212,7 +212,7 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol, 
	np->mc_loop	= 1;

	np->mc_all	= 1;

	np->pmtudisc	= IPV6_PMTUDISC_WANT;

	np->repflow	= net->ipv6.sysctl.flowlabel_reflect;

	np->repflow	= net->ipv6.sysctl.flowlabel_reflect & 1;

	sk->sk_ipv6only	= net->ipv6.sysctl.bindv6only;



	/* Init the ipv4 part of the socket since we can have sockets

net/ipv6/sysctl_net_ipv6.c

+3 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 


static int zero;

static int one = 1;

static int three = 3;

static int auto_flowlabels_min;

static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
@@ -114,6 +115,8 @@ static struct ctl_table ipv6_table_template[] = { 
		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= proc_dointvec,

		.extra1		= &zero,

		.extra2		= &three,

	},

	{

		.procname	= "max_dst_opts_number",

net/ipv6/tcp_ipv6.c

+12 −3
Original line number Diff line number Diff line
@@ -916,15 +916,17 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 
static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)

{

	const struct tcphdr *th = tcp_hdr(skb);

	struct ipv6hdr *ipv6h = ipv6_hdr(skb);

	u32 seq = 0, ack_seq = 0;

	struct tcp_md5sig_key *key = NULL;

#ifdef CONFIG_TCP_MD5SIG

	const __u8 *hash_location = NULL;

	struct ipv6hdr *ipv6h = ipv6_hdr(skb);

	unsigned char newhash[16];

	int genhash;

	struct sock *sk1 = NULL;

#endif

	__be32 label = 0;

	struct net *net;

	int oif = 0;



	if (th->rst)
@@ -936,6 +938,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) 
	if (!sk && !ipv6_unicast_destination(skb))

		return;



	net = dev_net(skb_dst(skb)->dev);

#ifdef CONFIG_TCP_MD5SIG

	rcu_read_lock();

	hash_location = tcp_parse_md5sig_option(th);
@@ -949,7 +952,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) 
		 * Incoming packet is checked with md5 hash with finding key,

		 * no RST generated if md5 hash doesn't match.

		 */

		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),

		sk1 = inet6_lookup_listener(net,

					   &tcp_hashinfo, NULL, 0,

					   &ipv6h->saddr,

					   th->source, &ipv6h->daddr,
@@ -979,9 +982,15 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) 
		oif = sk->sk_bound_dev_if;

		if (sk_fullsock(sk))

			trace_tcp_send_reset(sk, skb);

		if (sk->sk_state == TCP_TIME_WAIT)

			label = cpu_to_be32(inet_twsk(sk)->tw_flowlabel);

	} else {

		if (net->ipv6.sysctl.flowlabel_reflect & 2)

			label = ip6_flowlabel(ipv6h);

	}



	tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);

	tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0,

			     label);



#ifdef CONFIG_TCP_MD5SIG

out: