selftests: pmtu: Add pmtu_vti4_link_add_mtu test

This test checks that MTU given on vti link creation is actually
configured, and that tunnel is not created with an invalid MTU
value.

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

1 files changed, 44 insertions, 1 deletions

diff --git a/tools/testing/selftests/net/pmtu.sh b/tools/testing/selftests/net/pmtu.sh
index ba11433d17d8..d9f7ef2c213d 100755
--- a/tools/testing/selftests/net/pmtu.sh
+++ b/tools/testing/selftests/net/pmtu.sh
@@ -29,12 +29,17 @@
 #
 # - pmtu_vti6_default_mtu
 #       Same as above, for IPv6
+#
+# - pmtu_vti4_link_add_mtu
+#       Set up vti4 interface passing MTU value at link creation, check MTU is
+#       configured, and that link is not created with invalid MTU values
 
 tests="
         pmtu_vti6_exception     vti6: PMTU exceptions
         pmtu_vti4_exception     vti4: PMTU exceptions
         pmtu_vti4_default_mtu   vti4: default MTU assignment
-        pmtu_vti6_default_mtu   vti6: default MTU assignment"
+        pmtu_vti6_default_mtu   vti6: default MTU assignment
+        pmtu_vti4_link_add_mtu  vti4: MTU setting on link creation"
 
 NS_A="ns-$(mktemp -u XXXXXX)"
 NS_B="ns-$(mktemp -u XXXXXX)"
@@ -301,6 +306,44 @@ test_pmtu_vti6_default_mtu() {
         fi
 }
 
+test_pmtu_vti4_link_add_mtu() {
+        setup namespaces || return 2
+
+        ${ns_a} ip link add vti4_a type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10
+        [ $? -ne 0 ] && err "  vti not supported" && return 2
+        ${ns_a} ip link del vti4_a
+
+        fail=0
+
+        min=68
+        max=$((65528 - 20))
+        # Check invalid values first
+        for v in $((min - 1)) $((max + 1)); do
+                ${ns_a} ip link add vti4_a mtu ${v} type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10 2>/dev/null
+                # This can fail, or MTU can be adjusted to a proper value
+                [ $? -ne 0 ] && continue
+                mtu="$(link_get_mtu "${ns_a}" vti4_a)"
+                if [ ${mtu} -lt ${min} -o ${mtu} -gt ${max} ]; then
+                        err "  vti tunnel created with invalid MTU ${mtu}"
+                        fail=1
+                fi
+                ${ns_a} ip link del vti4_a
+        done
+
+        # Now check valid values
+        for v in ${min} 1300 ${max}; do
+                ${ns_a} ip link add vti4_a mtu ${v} type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10
+                mtu="$(link_get_mtu "${ns_a}" vti4_a)"
+                ${ns_a} ip link del vti4_a
+                if [ "${mtu}" != "${v}" ]; then
+                        err "  vti MTU ${mtu} doesn't match configured value ${v}"
+                        fail=1
+                fi
+        done
+
+        return ${fail}
+}
+
 trap cleanup EXIT
 
 exitcode=0