selftests: pmtu: Introduce list_flush_ipv4_exception test case

This test checks that route exceptions can be successfully listed and
flushed using ip -6 route {list,flush} cache.

v7: No changes

v6:
  - Merge this patch into series including fix, as it's also targeted
    for net-next
  - Drop left-over print of 'ip route list cache | wc -l'

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 60 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/pmtu.sh b/tools/testing/selftests/net/pmtu.sh
index 269e839b747e..f5004a9df229 100755
--- a/tools/testing/selftests/net/pmtu.sh
+++ b/tools/testing/selftests/net/pmtu.sh
@@ -112,6 +112,10 @@
 # - cleanup_ipv6_exception
 #       Same as above, but use IPv6 transport from A to B
 #
+# - list_flush_ipv4_exception
+#       Using the same topology as in pmtu_ipv4, create exceptions, and check
+#       they are shown when listing exception caches, gone after flushing them
+#
 # - list_flush_ipv6_exception
 #       Using the same topology as in pmtu_ipv6, create exceptions, and check
 #       they are shown when listing exception caches, gone after flushing them
@@ -156,6 +160,7 @@ tests="
         pmtu_vti6_link_change_mtu       vti6: MTU changes on link changes       0
         cleanup_ipv4_exception          ipv4: cleanup of cached exceptions      1
         cleanup_ipv6_exception          ipv6: cleanup of cached exceptions      1
+        list_flush_ipv4_exception       ipv4: list and flush cached exceptions  1
         list_flush_ipv6_exception       ipv6: list and flush cached exceptions  1"
 
 NS_A="ns-A"
@@ -1207,6 +1212,61 @@ run_test_nh() {
         USE_NH=no
 }
 
+test_list_flush_ipv4_exception() {
+        setup namespaces routing || return 2
+        trace "${ns_a}"  veth_A-R1    "${ns_r1}" veth_R1-A \
+              "${ns_r1}" veth_R1-B    "${ns_b}"  veth_B-R1 \
+              "${ns_a}"  veth_A-R2    "${ns_r2}" veth_R2-A \
+              "${ns_r2}" veth_R2-B    "${ns_b}"  veth_B-R2
+
+        dst_prefix1="${prefix4}.${b_r1}."
+        dst2="${prefix4}.${b_r2}.1"
+
+        # Set up initial MTU values
+        mtu "${ns_a}"  veth_A-R1 2000
+        mtu "${ns_r1}" veth_R1-A 2000
+        mtu "${ns_r1}" veth_R1-B 1500
+        mtu "${ns_b}"  veth_B-R1 1500
+
+        mtu "${ns_a}"  veth_A-R2 2000
+        mtu "${ns_r2}" veth_R2-A 2000
+        mtu "${ns_r2}" veth_R2-B 1500
+        mtu "${ns_b}"  veth_B-R2 1500
+
+        fail=0
+
+        # Add 100 addresses for veth endpoint on B reached by default A route
+        for i in $(seq 100 199); do
+                run_cmd ${ns_b} ip addr add "${dst_prefix1}${i}" dev veth_B-R1
+        done
+
+        # Create 100 cached route exceptions for path via R1, one via R2. Note
+        # that with IPv4 we need to actually cause a route lookup that matches
+        # the exception caused by ICMP, in order to actually have a cached
+        # route, so we need to ping each destination twice
+        for i in $(seq 100 199); do
+                run_cmd ${ns_a} ping -q -M want -i 0.1 -c 2 -s 1800 "${dst_prefix1}${i}"
+        done
+        run_cmd ${ns_a} ping -q -M want -i 0.1 -c 2 -s 1800 "${dst2}"
+
+        # Each exception is printed as two lines
+        if [ "$(${ns_a} ip route list cache | wc -l)" -ne 202 ]; then
+                err "  can't list cached exceptions"
+                fail=1
+        fi
+
+        run_cmd ${ns_a} ip route flush cache
+        pmtu1="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst_prefix}1)"
+        pmtu2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst_prefix}2)"
+        if [ -n "${pmtu1}" ] || [ -n "${pmtu2}" ] || \
+           [ -n "$(${ns_a} ip route list cache)" ]; then
+                err "  can't flush cached exceptions"
+                fail=1
+        fi
+
+        return ${fail}
+}
+
 test_list_flush_ipv6_exception() {
         setup namespaces routing || return 2
         trace "${ns_a}"  veth_A-R1    "${ns_r1}" veth_R1-A \