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authorToke Høiland-Jørgensen <toke@redhat.com>2021-06-18 14:04:36 +0300
committerDavid S. Miller <davem@davemloft.net>2021-06-18 22:13:24 +0300
commit7e9838b7915e29ae0dfe4a3e5f007c9dc6ab9b45 (patch)
tree8981bf80272488490fdba0286f38c093e61dcf3a /tools
parent321827477360934dc040e9d3c626bf1de6c3ab3c (diff)
downloadlinux-7e9838b7915e29ae0dfe4a3e5f007c9dc6ab9b45.tar.xz
selftests/net: Add icmp.sh for testing ICMP dummy address responses
This adds a new icmp.sh selftest for testing that the kernel will respond correctly with an ICMP unreachable message with the dummy (192.0.0.8) source address when there are no IPv4 addresses configured to use as source addresses. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools')
-rwxr-xr-xtools/testing/selftests/net/icmp.sh74
1 files changed, 74 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/icmp.sh b/tools/testing/selftests/net/icmp.sh
new file mode 100755
index 000000000000..e4b04cd1644a
--- /dev/null
+++ b/tools/testing/selftests/net/icmp.sh
@@ -0,0 +1,74 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Test for checking ICMP response with dummy address instead of 0.0.0.0.
+# Sets up two namespaces like:
+# +----------------------+ +--------------------+
+# | ns1 | v4-via-v6 routes: | ns2 |
+# | | ' | |
+# | +--------+ -> 172.16.1.0/24 -> +--------+ |
+# | | veth0 +--------------------------+ veth0 | |
+# | +--------+ <- 172.16.0.0/24 <- +--------+ |
+# | 172.16.0.1 | | 2001:db8:1::2/64 |
+# | 2001:db8:1::2/64 | | |
+# +----------------------+ +--------------------+
+#
+# And then tries to ping 172.16.1.1 from ns1. This results in a "net
+# unreachable" message being sent from ns2, but there is no IPv4 address set in
+# that address space, so the kernel should substitute the dummy address
+# 192.0.0.8 defined in RFC7600.
+
+NS1=ns1
+NS2=ns2
+H1_IP=172.16.0.1/32
+H1_IP6=2001:db8:1::1
+RT1=172.16.1.0/24
+PINGADDR=172.16.1.1
+RT2=172.16.0.0/24
+H2_IP6=2001:db8:1::2
+
+TMPFILE=$(mktemp)
+
+cleanup()
+{
+ rm -f "$TMPFILE"
+ ip netns del $NS1
+ ip netns del $NS2
+}
+
+trap cleanup EXIT
+
+# Namespaces
+ip netns add $NS1
+ip netns add $NS2
+
+# Connectivity
+ip -netns $NS1 link add veth0 type veth peer name veth0 netns $NS2
+ip -netns $NS1 link set dev veth0 up
+ip -netns $NS2 link set dev veth0 up
+ip -netns $NS1 addr add $H1_IP dev veth0
+ip -netns $NS1 addr add $H1_IP6/64 dev veth0 nodad
+ip -netns $NS2 addr add $H2_IP6/64 dev veth0 nodad
+ip -netns $NS1 route add $RT1 via inet6 $H2_IP6
+ip -netns $NS2 route add $RT2 via inet6 $H1_IP6
+
+# Make sure ns2 will respond with ICMP unreachable
+ip netns exec $NS2 sysctl -qw net.ipv4.icmp_ratelimit=0 net.ipv4.ip_forward=1
+
+# Run the test - a ping runs in the background, and we capture ICMP responses
+# with tcpdump; -c 1 means it should exit on the first ping, but add a timeout
+# in case something goes wrong
+ip netns exec $NS1 ping -w 3 -i 0.5 $PINGADDR >/dev/null &
+ip netns exec $NS1 timeout 10 tcpdump -tpni veth0 -c 1 'icmp and icmp[icmptype] != icmp-echo' > $TMPFILE 2>/dev/null
+
+# Parse response and check for dummy address
+# tcpdump output looks like:
+# IP 192.0.0.8 > 172.16.0.1: ICMP net 172.16.1.1 unreachable, length 92
+RESP_IP=$(awk '{print $2}' < $TMPFILE)
+if [[ "$RESP_IP" != "192.0.0.8" ]]; then
+ echo "FAIL - got ICMP response from $RESP_IP, should be 192.0.0.8"
+ exit 1
+else
+ echo "OK"
+ exit 0
+fi