diff options
| author | Ido Schimmel <idosch@nvidia.com> | 2025-09-08 10:32:37 +0300 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-09-11 12:22:38 +0200 |
| commit | 2e6428100b1613d85d5442c14ee18c5a47054daf (patch) | |
| tree | 6ab8bf4345762f697f0c9b06ccb99aa251d85144 | |
| parent | 5c9c78224fc3045c8ffe1a4c7d25d277e2e02b7b (diff) | |
selftests: traceroute: Test traceroute with different source IPs
When generating ICMP error messages, the kernel will prefer a source IP
that is on the same subnet as the destination IP (see
inet_select_addr()). Test this behavior by invoking traceroute with
different source IPs and checking that the ICMP error message is
generated with a source IP in the same subnet.
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250908073238.119240-8-idosch@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rwxr-xr-x | tools/testing/selftests/net/traceroute.sh | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/tools/testing/selftests/net/traceroute.sh b/tools/testing/selftests/net/traceroute.sh index 8dc4e5d03e43..0ab9eccf1499 100755 --- a/tools/testing/selftests/net/traceroute.sh +++ b/tools/testing/selftests/net/traceroute.sh @@ -196,9 +196,10 @@ run_traceroute6() ################################################################################ # traceroute test # -# Verify that traceroute from H1 to H2 shows 1.0.1.1 in this scenario +# Verify that traceroute from H1 to H2 shows 1.0.3.1 and 1.0.1.1 when +# traceroute uses 1.0.3.3 and 1.0.1.3 as the source IP, respectively. # -# 1.0.3.1/24 +# 1.0.3.3/24 1.0.3.1/24 # ---- 1.0.1.3/24 1.0.1.1/24 ---- 1.0.2.1/24 1.0.2.4/24 ---- # |H1|--------------------------|R1|--------------------------|H2| # ---- N1 ---- N2 ---- @@ -226,6 +227,7 @@ setup_traceroute() connect_ns $h1 eth0 1.0.1.3/24 - \ $router eth1 1.0.3.1/24 - + ip -n "$h1" addr add 1.0.3.3/24 dev eth0 ip netns exec $h1 ip route add default via 1.0.1.1 ip netns exec $router ip addr add 1.0.1.1/24 dev eth1 @@ -248,9 +250,12 @@ run_traceroute() RET=0 - # traceroute host-2 from host-1 (expects 1.0.1.1). Takes a while. - run_cmd $h1 "traceroute 1.0.2.4 | grep -q 1.0.1.1" + # traceroute host-2 from host-1. Expect a source IP that is on the same + # subnet as destination IP of the ICMP error message. + run_cmd "$h1" "traceroute -s 1.0.1.3 1.0.2.4 | grep -q 1.0.1.1" check_err $? "traceroute did not return 1.0.1.1" + run_cmd "$h1" "traceroute -s 1.0.3.3 1.0.2.4 | grep -q 1.0.3.1" + check_err $? "traceroute did not return 1.0.3.1" log_test "IPv4 traceroute" cleanup_traceroute |