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 # Kselftest framework requirement - SKIP code is 4.
34 # nettest can be run from PATH or from same directory as this selftest
35 if ! which nettest >/dev/null; then
37 if ! which nettest >/dev/null; then
38 echo "'nettest' command not found; skipping tests"
45 hide_output(){ exec 3>&1 4>&2 >/dev/null 2>/dev/null; }
46 show_output(){ exec >&3 2>&4; }
50 printf "TEST: %-60s [ OK ]\n" "${2}"
52 printf "TEST: %-60s [FAIL]\n" "${2}"
58 # Perform a simple set of link tests between a pair of
59 # IP addresses on a shared (virtual) segment, using
62 # Arguments: ip_a ip_b prefix_length test_description
64 # Caller must set up foo-ns and bar-ns namespaces
65 # containing linked veth devices foo and bar,
68 ip -n foo-ns address add $1/$3 dev foo || return 1
69 ip -n foo-ns link set foo up || return 1
70 ip -n bar-ns address add $2/$3 dev bar || return 1
71 ip -n bar-ns link set bar up || return 1
73 ip netns exec foo-ns timeout 2 ping -c 1 $2 || return 1
74 ip netns exec bar-ns timeout 2 ping -c 1 $1 || return 1
76 nettest -B -N bar-ns -O foo-ns -r $1 || return 1
77 nettest -B -N foo-ns -O bar-ns -r $2 || return 1
83 # Perform a simple set of gateway tests.
85 # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix
88 # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description
89 # Displays test result and returns success or failure.
91 # Caller must set up foo-ns, bar-ns, and router-ns
92 # containing linked veth devices foo-foo1, bar1-bar
93 # (foo in foo-ns, foo1 and bar1 in router-ns, and
96 ip -n foo-ns address add $1/$5 dev foo || return 1
97 ip -n foo-ns link set foo up || return 1
98 ip -n foo-ns route add default via $2 || return 1
99 ip -n bar-ns address add $4/$5 dev bar || return 1
100 ip -n bar-ns link set bar up || return 1
101 ip -n bar-ns route add default via $3 || return 1
102 ip -n router-ns address add $2/$5 dev foo1 || return 1
103 ip -n router-ns link set foo1 up || return 1
104 ip -n router-ns address add $3/$5 dev bar1 || return 1
105 ip -n router-ns link set bar1 up || return 1
107 echo 1 | ip netns exec router-ns tee /proc/sys/net/ipv4/ip_forward
109 ip netns exec foo-ns timeout 2 ping -c 1 $2 || return 1
110 ip netns exec foo-ns timeout 2 ping -c 1 $4 || return 1
111 ip netns exec bar-ns timeout 2 ping -c 1 $3 || return 1
112 ip netns exec bar-ns timeout 2 ping -c 1 $1 || return 1
114 nettest -B -N bar-ns -O foo-ns -r $1 || return 1
115 nettest -B -N foo-ns -O bar-ns -r $4 || return 1
121 # Sets up veth link and tries to connect over it.
122 # Arguments: ip_a ip_b prefix_len test_description
126 ip link add foo netns foo-ns type veth peer name bar netns bar-ns
129 _do_segmenttest "$@" || test_result=1
131 ip netns pids foo-ns | xargs -r kill -9
132 ip netns pids bar-ns | xargs -r kill -9
137 # inverted tests will expect failure instead of success
138 [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result`
140 show_result $test_result "$4"
144 # Sets up a simple gateway and tries to connect through it.
145 # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix
146 # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description
147 # Returns success or failure.
152 ip netns add router-ns
153 ip link add foo netns foo-ns type veth peer name foo1 netns router-ns
154 ip link add bar netns bar-ns type veth peer name bar1 netns router-ns
157 _do_route_test "$@" || test_result=1
159 ip netns pids foo-ns | xargs -r kill -9
160 ip netns pids bar-ns | xargs -r kill -9
161 ip netns pids router-ns | xargs -r kill -9
164 ip netns del router-ns
168 # inverted tests will expect failure instead of success
169 [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result`
170 show_result $test_result "$6"
173 echo "###########################################################################"
174 echo "Unicast address extensions tests (behavior of reserved IPv4 addresses)"
175 echo "###########################################################################"
177 # Test support for 240/4
178 segmenttest 240.1.2.1 240.1.2.4 24 "assign and ping within 240/4 (1 of 2) (is allowed)"
179 segmenttest 250.100.2.1 250.100.30.4 16 "assign and ping within 240/4 (2 of 2) (is allowed)"
181 # Test support for 0/8
182 segmenttest 0.1.2.17 0.1.2.23 24 "assign and ping within 0/8 (1 of 2) (is allowed)"
183 segmenttest 0.77.240.17 0.77.2.23 16 "assign and ping within 0/8 (2 of 2) (is allowed)"
185 # Even 255.255/16 is OK!
186 segmenttest 255.255.3.1 255.255.50.77 16 "assign and ping inside 255.255/16 (is allowed)"
189 segmenttest 255.255.255.1 255.255.255.254 24 "assign and ping inside 255.255.255/24 (is allowed)"
191 # Routing between different networks
192 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)"
193 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)"
195 # Test support for lowest address ending in .0
196 segmenttest 5.10.15.20 5.10.15.0 24 "assign and ping lowest address (/24)"
198 # Test support for lowest address not ending in .0
199 segmenttest 192.168.101.192 192.168.101.193 26 "assign and ping lowest address (/26)"
201 # Routing using lowest address as a gateway/endpoint
202 route_test 192.168.42.1 192.168.42.0 9.8.7.6 9.8.7.0 24 "routing using lowest address"
204 # ==============================================
205 # ==== TESTS THAT CURRENTLY EXPECT FAILURE =====
206 # ==============================================
208 # It should still not be possible to use 0.0.0.0 or 255.255.255.255
209 # as a unicast address. Thus, these tests expect failure.
210 segmenttest 0.0.1.5 0.0.0.0 16 "assigning 0.0.0.0 (is forbidden)"
211 segmenttest 255.255.255.1 255.255.255.255 16 "assigning 255.255.255.255 (is forbidden)"
213 # Test support for not having all of 127 be loopback
214 # Currently Linux does not allow this, so this should fail too
215 segmenttest 127.99.4.5 127.99.4.6 16 "assign and ping inside 127/8 (is forbidden)"
217 # Test support for unicast use of class D
218 # Currently Linux does not allow this, so this should fail too
219 segmenttest 225.1.2.3 225.1.2.200 24 "assign and ping class D address (is forbidden)"
221 # Routing using class D as a gateway
222 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)"
224 # Routing using 127/8
225 # Currently Linux does not allow this, so this should fail too
226 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)"
229 # =====================================================
230 # ==== END OF TESTS THAT CURRENTLY EXPECT FAILURE =====
231 # =====================================================