[ovs-dev] [PATCH] OVN: add ICMPv6 time exceeded support to OVN logical router
Lorenzo Bianconi
lorenzo.bianconi at redhat.com
Mon Jul 2 15:19:22 UTC 2018
Using icmp6 action, send an ICMPv6 time exceeded frame whenever
an OVN logical router receives an IPv6 packets whose TTL has
expired (ip.ttl == {0, 1})
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
---
ovn/northd/ovn-northd.8.xml | 12 +++++++++++-
ovn/northd/ovn-northd.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 42 insertions(+), 1 deletion(-)
diff --git a/ovn/northd/ovn-northd.8.xml b/ovn/northd/ovn-northd.8.xml
index 4d0bab476..08e0325a0 100644
--- a/ovn/northd/ovn-northd.8.xml
+++ b/ovn/northd/ovn-northd.8.xml
@@ -1383,7 +1383,8 @@ nd_na {
address is <var>A</var>, a priority-40 flow with match <code>inport
== <var>P</var> && ip.ttl == {0, 1} &&
!ip.later_frag</code> matches packets whose TTL has expired, with the
- following actions to send an ICMP time exceeded reply:
+ following actions to send an ICMP time exceeded reply for IPv4 and
+ IPv6 respectively:
</p>
<pre>
@@ -1395,6 +1396,15 @@ icmp4 {
ip.ttl = 255;
next;
};
+
+icmp6 {
+ icmp6.type = 3; /* Time exceeded. */
+ icmp6.code = 0; /* TTL exceeded in transit. */
+ ip6.dst = ip6.src;
+ ip6.src = <var>A</var>;
+ ip.ttl = 255;
+ next;
+};
</pre>
</li>
diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
index 2febf7b8e..8ed0c4987 100644
--- a/ovn/northd/ovn-northd.c
+++ b/ovn/northd/ovn-northd.c
@@ -5328,6 +5328,37 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
ds_cstr(&match), action);
}
}
+
+ /* ICMPv6 time exceeded */
+ for (int i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) {
+ /* skip link-local address */
+ if (in6_is_lla(&op->lrp_networks.ipv6_addrs[i].network)) {
+ continue;
+ }
+
+ ds_clear(&match);
+ ds_clear(&actions);
+
+ ds_put_format(&match,
+ "inport == %s && ip6 && "
+ "ip6.src == %s/%d && "
+ "ip.ttl == {0, 1} && !ip.later_frag",
+ op->json_key,
+ op->lrp_networks.ipv6_addrs[i].network_s,
+ op->lrp_networks.ipv6_addrs[i].plen);
+ ds_put_format(&actions,
+ "icmp6 {"
+ "eth.dst <-> eth.src; "
+ "ip6.dst = ip6.src; "
+ "ip6.src = %s; "
+ "ip.ttl = 255; "
+ "icmp6.type = 3; /* Time exceeded */ "
+ "icmp6.code = 0; /* TTL exceeded in transit */ "
+ "next; };",
+ op->lrp_networks.ipv6_addrs[i].addr_s);
+ ovn_lflow_add(lflows, op->od, S_ROUTER_IN_IP_INPUT, 40,
+ ds_cstr(&match), ds_cstr(&actions));
+ }
}
/* NAT, Defrag and load balancing. */
--
2.17.1
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