@@ -22,6 +22,7 @@ TEST_PROGS += devlink_port_split.py
TEST_PROGS += drop_monitor_tests.sh
TEST_PROGS += vrf_route_leaking.sh
TEST_PROGS += bareudp.sh
+TEST_PROGS += unicast_extensions.sh
TEST_PROGS_EXTENDED := in_netns.sh
TEST_GEN_FILES = socket nettest
TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy reuseport_addr_any
new file mode 100755
@@ -0,0 +1,228 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# By Seth Schoen (c) 2021, for the IPv4 Unicast Extensions Project
+# Thanks to David Ahern for help and advice on nettest modifications.
+#
+# Self-tests for IPv4 address extensions: the kernel's ability to accept
+# certain traditionally unused or unallocated IPv4 addresses. For each kind
+# of address, we test for interface assignment, ping, TCP, and forwarding.
+# Must be run as root (to manipulate network namespaces and virtual
+# interfaces).
+#
+# Things we test for here:
+#
+# * Currently the kernel accepts addresses in 0/8 and 240/4 as valid.
+#
+# * Notwithstanding that, 0.0.0.0 and 255.255.255.255 cannot be assigned.
+#
+# * Currently the kernel DOES NOT accept unicast use of the lowest
+# address in an IPv4 subnet (e.g. 192.168.100.0/32 in 192.168.100.0/24).
+# This is treated as a second broadcast address, for compatibility
+# with 4.2BSD (!).
+#
+# * Currently the kernel DOES NOT accept unicast use of any of 127/8.
+#
+# * Currently the kernel DOES NOT accept unicast use of any of 224/4.
+#
+# These tests provide an easy way to flip the expected result of any
+# of these behaviors for testing kernel patches that change them.
+
+# nettest can be run from PATH or from same directory as this selftest
+if ! which nettest >/dev/null; then
+ PATH=$PWD:$PATH
+ if ! which nettest >/dev/null; then
+ echo "'nettest' command not found; skipping tests"
+ exit 0
+ fi
+fi
+
+result=0
+
+hide_output(){ exec 3>&1 4>&2 >/dev/null 2>/dev/null; }
+show_output(){ exec >&3 2>&4; }
+
+show_result(){
+ if [ $1 -eq 0 ]; then
+ printf "TEST: %-60s [ OK ]\n" "${2}"
+ else
+ printf "TEST: %-60s [FAIL]\n" "${2}"
+ result=1
+ fi
+}
+
+_do_segmenttest(){
+ # Perform a simple set of link tests between a pair of
+ # IP addresses on a shared (virtual) segment, using
+ # ping and nettest.
+ # foo --- bar
+ # Arguments: ip_a ip_b prefix_length test_description
+ #
+ # Caller must set up foo-ns and bar-ns namespaces
+ # containing linked veth devices foo and bar,
+ # respectively.
+
+ ip -n foo-ns address add $1/$3 dev foo || return 1
+ ip -n foo-ns link set foo up || return 1
+ ip -n bar-ns address add $2/$3 dev bar || return 1
+ ip -n bar-ns link set bar up || return 1
+
+ ip netns exec foo-ns timeout 2 ping -c 1 $2 || return 1
+ ip netns exec bar-ns timeout 2 ping -c 1 $1 || return 1
+
+ nettest -B -N bar-ns -O foo-ns -r $1 || return 1
+ nettest -B -N foo-ns -O bar-ns -r $2 || return 1
+
+ return 0
+}
+
+_do_route_test(){
+ # Perform a simple set of gateway tests.
+ #
+ # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix
+ # host gateway host
+ #
+ # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description
+ # Displays test result and returns success or failure.
+
+ # Caller must set up foo-ns, bar-ns, and router-ns
+ # containing linked veth devices foo-foo1, bar1-bar
+ # (foo in foo-ns, foo1 and bar1 in router-ns, and
+ # bar in bar-ns).
+
+ ip -n foo-ns address add $1/$5 dev foo || return 1
+ ip -n foo-ns link set foo up || return 1
+ ip -n foo-ns route add default via $2 || return 1
+ ip -n bar-ns address add $4/$5 dev bar || return 1
+ ip -n bar-ns link set bar up || return 1
+ ip -n bar-ns route add default via $3 || return 1
+ ip -n router-ns address add $2/$5 dev foo1 || return 1
+ ip -n router-ns link set foo1 up || return 1
+ ip -n router-ns address add $3/$5 dev bar1 || return 1
+ ip -n router-ns link set bar1 up || return 1
+
+ echo 1 | ip netns exec router-ns tee /proc/sys/net/ipv4/ip_forward
+
+ ip netns exec foo-ns timeout 2 ping -c 1 $2 || return 1
+ ip netns exec foo-ns timeout 2 ping -c 1 $4 || return 1
+ ip netns exec bar-ns timeout 2 ping -c 1 $3 || return 1
+ ip netns exec bar-ns timeout 2 ping -c 1 $1 || return 1
+
+ nettest -B -N bar-ns -O foo-ns -r $1 || return 1
+ nettest -B -N foo-ns -O bar-ns -r $4 || return 1
+
+ return 0
+}
+
+segmenttest(){
+ # Sets up veth link and tries to connect over it.
+ # Arguments: ip_a ip_b prefix_len test_description
+ hide_output
+ ip netns add foo-ns
+ ip netns add bar-ns
+ ip link add foo netns foo-ns type veth peer name bar netns bar-ns
+
+ test_result=0
+ _do_segmenttest "$@" || test_result=1
+
+ ip netns pids foo-ns | xargs -r kill -9
+ ip netns pids bar-ns | xargs -r kill -9
+ ip netns del foo-ns
+ ip netns del bar-ns
+ show_output
+
+ # inverted tests will expect failure instead of success
+ [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result`
+
+ show_result $test_result "$4"
+}
+
+route_test(){
+ # Sets up a simple gateway and tries to connect through it.
+ # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix
+ # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description
+ # Returns success or failure.
+
+ hide_output
+ ip netns add foo-ns
+ ip netns add bar-ns
+ ip netns add router-ns
+ ip link add foo netns foo-ns type veth peer name foo1 netns router-ns
+ ip link add bar netns bar-ns type veth peer name bar1 netns router-ns
+
+ test_result=0
+ _do_route_test "$@" || test_result=1
+
+ ip netns pids foo-ns | xargs -r kill -9
+ ip netns pids bar-ns | xargs -r kill -9
+ ip netns pids router-ns | xargs -r kill -9
+ ip netns del foo-ns
+ ip netns del bar-ns
+ ip netns del router-ns
+
+ show_output
+
+ # inverted tests will expect failure instead of success
+ [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result`
+ show_result $test_result "$6"
+}
+
+echo "###########################################################################"
+echo "Unicast address extensions tests (behavior of reserved IPv4 addresses)"
+echo "###########################################################################"
+#
+# Test support for 240/4
+segmenttest 240.1.2.1 240.1.2.4 24 "assign and ping within 240/4 (1 of 2) (is allowed)"
+segmenttest 250.100.2.1 250.100.30.4 16 "assign and ping within 240/4 (2 of 2) (is allowed)"
+#
+# Test support for 0/8
+segmenttest 0.1.2.17 0.1.2.23 24 "assign and ping within 0/8 (1 of 2) (is allowed)"
+segmenttest 0.77.240.17 0.77.2.23 16 "assign and ping within 0/8 (2 of 2) (is allowed)"
+#
+# Even 255.255/16 is OK!
+segmenttest 255.255.3.1 255.255.50.77 16 "assign and ping inside 255.255/16 (is allowed)"
+#
+# Or 255.255.255/24
+segmenttest 255.255.255.1 255.255.255.254 24 "assign and ping inside 255.255.255/24 (is allowed)"
+#
+# Routing between different networks
+route_test 240.5.6.7 240.5.6.1 255.1.2.1 255.1.2.3 24 "route between 240.5.6/24 and 255.1.2/24 (is allowed)"
+route_test 0.200.6.7 0.200.38.1 245.99.101.1 245.99.200.111 16 "route between 0.200/16 and 245.99/16 (is allowed)"
+#
+# ==============================================
+# ==== TESTS THAT CURRENTLY EXPECT FAILURE =====
+# ==============================================
+expect_failure=true
+# It should still not be possible to use 0.0.0.0 or 255.255.255.255
+# as a unicast address. Thus, these tests expect failure.
+segmenttest 0.0.1.5 0.0.0.0 16 "assigning 0.0.0.0 (is forbidden)"
+segmenttest 255.255.255.1 255.255.255.255 16 "assigning 255.255.255.255 (is forbidden)"
+#
+# Test support for not having all of 127 be loopback
+# Currently Linux does not allow this, so this should fail too
+segmenttest 127.99.4.5 127.99.4.6 16 "assign and ping inside 127/8 (is forbidden)"
+#
+# Test support for lowest address
+# Currently Linux does not allow this, so this should fail too
+segmenttest 5.10.15.20 5.10.15.0 24 "assign and ping lowest address (is forbidden)"
+#
+# Routing using lowest address as a gateway/endpoint
+# Currently Linux does not allow this, so this should fail too
+route_test 192.168.42.1 192.168.42.0 9.8.7.6 9.8.7.0 24 "routing using lowest address (is forbidden)"
+#
+# Test support for unicast use of class D
+# Currently Linux does not allow this, so this should fail too
+segmenttest 225.1.2.3 225.1.2.200 24 "assign and ping class D address (is forbidden)"
+#
+# Routing using class D as a gateway
+route_test 225.1.42.1 225.1.42.2 9.8.7.6 9.8.7.1 24 "routing using class D (is forbidden)"
+#
+# Routing using 127/8
+# Currently Linux does not allow this, so this should fail too
+route_test 127.99.2.3 127.99.2.4 200.1.2.3 200.1.2.4 24 "routing using 127/8 (is forbidden)"
+#
+unset expect_failure
+# =====================================================
+# ==== END OF TESTS THAT CURRENTLY EXPECT FAILURE =====
+# =====================================================
+exit ${result}