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Merge branch 'tcp-flowlabel'

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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: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
2019-06-05 19:05:01 -07:00
parent e736bf72af 50a8accf10
commit ec01147a4b
4 changed files with 31 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
Documentation/networking/ip-sysctl.txt
View File

@ -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.

2
net/ipv6/af_inet6.c
View File

@ -212,7 +212,7 @@ lookup_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

3
net/ipv6/sysctl_net_ipv6.c
View File

@ -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",

15
net/ipv6/tcp_ipv6.c
View File

@ -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: