2 # SPDX-License-Identifier: GPL-2.0
4 # By Seth Schoen (c) 2021, for the IPv4 Unicast Extensions Project
5 # Thanks to David Ahern for help and advice on nettest modifications.
7 # Self-tests for IPv4 address extensions: the kernel's ability to accept
8 # certain traditionally unused or unallocated IPv4 addresses. For each kind
9 # of address, we test for interface assignment, ping, TCP, and forwarding.
10 # Must be run as root (to manipulate network namespaces and virtual
13 # Things we test for here:
15 # * Currently the kernel accepts addresses in 0/8 and 240/4 as valid.
17 # * Notwithstanding that, 0.0.0.0 and 255.255.255.255 cannot be assigned.
19 # * Currently the kernel DOES NOT accept unicast use of the lowest
20 # address in an IPv4 subnet (e.g. 192.168.100.0/32 in 192.168.100.0/24).
21 # This is treated as a second broadcast address, for compatibility
24 # * Currently the kernel DOES NOT accept unicast use of any of 127/8.
26 # * Currently the kernel DOES NOT accept unicast use of any of 224/4.
28 # These tests provide an easy way to flip the expected result of any
29 # of these behaviors for testing kernel patches that change them.
31 # nettest can be run from PATH or from same directory as this selftest
32 if ! which nettest >/dev/null; then
34 if ! which nettest >/dev/null; then
35 echo "'nettest' command not found; skipping tests"
42 hide_output(){ exec 3>&1 4>&2 >/dev/null 2>/dev/null; }
43 show_output(){ exec >&3 2>&4; }
47 printf "TEST: %-60s [ OK ]\n" "${2}"
49 printf "TEST: %-60s [FAIL]\n" "${2}"
55 # Perform a simple set of link tests between a pair of
56 # IP addresses on a shared (virtual) segment, using
59 # Arguments: ip_a ip_b prefix_length test_description
61 # Caller must set up foo-ns and bar-ns namespaces
62 # containing linked veth devices foo and bar,
65 ip -n foo-ns address add $1/$3 dev foo || return 1
66 ip -n foo-ns link set foo up || return 1
67 ip -n bar-ns address add $2/$3 dev bar || return 1
68 ip -n bar-ns link set bar up || return 1
70 ip netns exec foo-ns timeout 2 ping -c 1 $2 || return 1
71 ip netns exec bar-ns timeout 2 ping -c 1 $1 || return 1
73 nettest -B -N bar-ns -O foo-ns -r $1 || return 1
74 nettest -B -N foo-ns -O bar-ns -r $2 || return 1
80 # Perform a simple set of gateway tests.
82 # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix
85 # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description
86 # Displays test result and returns success or failure.
88 # Caller must set up foo-ns, bar-ns, and router-ns
89 # containing linked veth devices foo-foo1, bar1-bar
90 # (foo in foo-ns, foo1 and bar1 in router-ns, and
93 ip -n foo-ns address add $1/$5 dev foo || return 1
94 ip -n foo-ns link set foo up || return 1
95 ip -n foo-ns route add default via $2 || return 1
96 ip -n bar-ns address add $4/$5 dev bar || return 1
97 ip -n bar-ns link set bar up || return 1
98 ip -n bar-ns route add default via $3 || return 1
99 ip -n router-ns address add $2/$5 dev foo1 || return 1
100 ip -n router-ns link set foo1 up || return 1
101 ip -n router-ns address add $3/$5 dev bar1 || return 1
102 ip -n router-ns link set bar1 up || return 1
104 echo 1 | ip netns exec router-ns tee /proc/sys/net/ipv4/ip_forward
106 ip netns exec foo-ns timeout 2 ping -c 1 $2 || return 1
107 ip netns exec foo-ns timeout 2 ping -c 1 $4 || return 1
108 ip netns exec bar-ns timeout 2 ping -c 1 $3 || return 1
109 ip netns exec bar-ns timeout 2 ping -c 1 $1 || return 1
111 nettest -B -N bar-ns -O foo-ns -r $1 || return 1
112 nettest -B -N foo-ns -O bar-ns -r $4 || return 1
118 # Sets up veth link and tries to connect over it.
119 # Arguments: ip_a ip_b prefix_len test_description
123 ip link add foo netns foo-ns type veth peer name bar netns bar-ns
126 _do_segmenttest "$@" || test_result=1
128 ip netns pids foo-ns | xargs -r kill -9
129 ip netns pids bar-ns | xargs -r kill -9
134 # inverted tests will expect failure instead of success
135 [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result`
137 show_result $test_result "$4"
141 # Sets up a simple gateway and tries to connect through it.
142 # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix
143 # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description
144 # Returns success or failure.
149 ip netns add router-ns
150 ip link add foo netns foo-ns type veth peer name foo1 netns router-ns
151 ip link add bar netns bar-ns type veth peer name bar1 netns router-ns
154 _do_route_test "$@" || test_result=1
156 ip netns pids foo-ns | xargs -r kill -9
157 ip netns pids bar-ns | xargs -r kill -9
158 ip netns pids router-ns | xargs -r kill -9
161 ip netns del router-ns
165 # inverted tests will expect failure instead of success
166 [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result`
167 show_result $test_result "$6"
170 echo "###########################################################################"
171 echo "Unicast address extensions tests (behavior of reserved IPv4 addresses)"
172 echo "###########################################################################"
174 # Test support for 240/4
175 segmenttest 240.1.2.1 240.1.2.4 24 "assign and ping within 240/4 (1 of 2) (is allowed)"
176 segmenttest 250.100.2.1 250.100.30.4 16 "assign and ping within 240/4 (2 of 2) (is allowed)"
178 # Test support for 0/8
179 segmenttest 0.1.2.17 0.1.2.23 24 "assign and ping within 0/8 (1 of 2) (is allowed)"
180 segmenttest 0.77.240.17 0.77.2.23 16 "assign and ping within 0/8 (2 of 2) (is allowed)"
182 # Even 255.255/16 is OK!
183 segmenttest 255.255.3.1 255.255.50.77 16 "assign and ping inside 255.255/16 (is allowed)"
186 segmenttest 255.255.255.1 255.255.255.254 24 "assign and ping inside 255.255.255/24 (is allowed)"
188 # Routing between different networks
189 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)"
190 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)"
192 # ==============================================
193 # ==== TESTS THAT CURRENTLY EXPECT FAILURE =====
194 # ==============================================
196 # It should still not be possible to use 0.0.0.0 or 255.255.255.255
197 # as a unicast address. Thus, these tests expect failure.
198 segmenttest 0.0.1.5 0.0.0.0 16 "assigning 0.0.0.0 (is forbidden)"
199 segmenttest 255.255.255.1 255.255.255.255 16 "assigning 255.255.255.255 (is forbidden)"
201 # Test support for not having all of 127 be loopback
202 # Currently Linux does not allow this, so this should fail too
203 segmenttest 127.99.4.5 127.99.4.6 16 "assign and ping inside 127/8 (is forbidden)"
205 # Test support for lowest address
206 # Currently Linux does not allow this, so this should fail too
207 segmenttest 5.10.15.20 5.10.15.0 24 "assign and ping lowest address (is forbidden)"
209 # Routing using lowest address as a gateway/endpoint
210 # Currently Linux does not allow this, so this should fail too
211 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)"
213 # Test support for unicast use of class D
214 # Currently Linux does not allow this, so this should fail too
215 segmenttest 225.1.2.3 225.1.2.200 24 "assign and ping class D address (is forbidden)"
217 # Routing using class D as a gateway
218 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)"
220 # Routing using 127/8
221 # Currently Linux does not allow this, so this should fail too
222 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)"
225 # =====================================================
226 # ==== END OF TESTS THAT CURRENTLY EXPECT FAILURE =====
227 # =====================================================