From a346abe051bd2bd0d5d0140b2da9ec95639acad7 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 1 Jul 2019 06:39:36 -0700
Subject: [PATCH] ipv6: icmp: allow flowlabel reflection in echo replies
Extend flowlabel_reflect bitmask to allow conditional
reflection of incoming flowlabels in echo replies.
Note this has precedence against auto flowlabels.
Add flowlabel_reflect enum to replace hard coded
values.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
Documentation/networking/ip-sysctl.txt | 4 +++-
include/net/ipv6.h | 7 +++++++
net/ipv6/af_inet6.c | 2 +-
net/ipv6/icmp.c | 3 +++
net/ipv6/sysctl_net_ipv6.c | 4 ++--
net/ipv6/tcp_ipv6.c | 2 +-
6 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index e0d8a96e2c671..f0e6d1f53485d 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1452,7 +1452,7 @@ flowlabel_reflect - INTEGER
environments. See RFC 7690 and:
https://tools.ietf.org/html/draft-wang-6man-flow-label-reflection-01
- This is a mask of two bits.
+ This is a bitmask.
1: enabled for established flows
Note that this prevents automatic flowlabel changes, as done
@@ -1463,6 +1463,8 @@ flowlabel_reflect - INTEGER
If set, a RST packet sent in response to a SYN packet on a closed
port will reflect the incoming flow label.
+ 4: enabled for ICMPv6 echo reply messages.
+
Default: 0
fib_multipath_hash_policy - INTEGER
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index b41f6a0fa903e..8eca5fb30376f 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -301,6 +301,13 @@ struct ipv6_txoptions {
/* Option buffer, as read by IPV6_PKTOPTIONS, starts here. */
};
+/* flowlabel_reflect sysctl values */
+enum flowlabel_reflect {
+ FLOWLABEL_REFLECT_ESTABLISHED = 1,
+ FLOWLABEL_REFLECT_TCP_RESET = 2,
+ FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES = 4,
+};
+
struct ip6_flowlabel {
struct ip6_flowlabel __rcu *next;
__be32 label;
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 7382a927d1eb7..8369af32cef61 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -208,7 +208,7 @@ 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 & 1;
+ np->repflow = net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ESTABLISHED;
sk->sk_ipv6only = net->ipv6.sysctl.bindv6only;
/* Init the ipv4 part of the socket since we can have sockets
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 12906301ec7ba..62c997201970a 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -703,6 +703,9 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
memset(&fl6, 0, sizeof(fl6));
+ if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)
+ fl6.flowlabel = ip6_flowlabel(ipv6_hdr(skb));
+
fl6.flowi6_proto = IPPROTO_ICMPV6;
fl6.daddr = ipv6_hdr(skb)->saddr;
if (saddr)
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 6d86fac472e72..8b3fe81783ed9 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -23,7 +23,7 @@
static int zero;
static int one = 1;
-static int three = 3;
+static int flowlabel_reflect_max = 0x7;
static int auto_flowlabels_min;
static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
@@ -116,7 +116,7 @@ static struct ctl_table ipv6_table_template[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = &zero,
- .extra2 = &three,
+ .extra2 = &flowlabel_reflect_max,
},
{
.procname = "max_dst_opts_number",
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 408d9ec269715..4f3f99b398209 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -989,7 +989,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *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)
+ if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_TCP_RESET)
label = ip6_flowlabel(ipv6h);
}
--
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