1#!/bin/sh 2# SPDX-License-Identifier: GPL-2.0 3# 4# By Seth Schoen (c) 2021, for the IPv4 Unicast Extensions Project 5# Thanks to David Ahern for help and advice on nettest modifications. 6# 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 11# interfaces). 12# 13# Things we test for here: 14# 15# * Currently the kernel accepts addresses in 0/8 and 240/4 as valid. 16# 17# * Notwithstanding that, 0.0.0.0 and 255.255.255.255 cannot be assigned. 18# 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 22# with 4.2BSD (!). 23# 24# * Currently the kernel DOES NOT accept unicast use of any of 127/8. 25# 26# * Currently the kernel DOES NOT accept unicast use of any of 224/4. 27# 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. 30 31# nettest can be run from PATH or from same directory as this selftest 32if ! which nettest >/dev/null; then 33 PATH=$PWD:$PATH 34 if ! which nettest >/dev/null; then 35 echo "'nettest' command not found; skipping tests" 36 exit 0 37 fi 38fi 39 40result=0 41 42hide_output(){ exec 3>&1 4>&2 >/dev/null 2>/dev/null; } 43show_output(){ exec >&3 2>&4; } 44 45show_result(){ 46 if [ $1 -eq 0 ]; then 47 printf "TEST: %-60s [ OK ]\n" "${2}" 48 else 49 printf "TEST: %-60s [FAIL]\n" "${2}" 50 result=1 51 fi 52} 53 54_do_segmenttest(){ 55 # Perform a simple set of link tests between a pair of 56 # IP addresses on a shared (virtual) segment, using 57 # ping and nettest. 58 # foo --- bar 59 # Arguments: ip_a ip_b prefix_length test_description 60 # 61 # Caller must set up foo-ns and bar-ns namespaces 62 # containing linked veth devices foo and bar, 63 # respectively. 64 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 69 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 72 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 75 76 return 0 77} 78 79_do_route_test(){ 80 # Perform a simple set of gateway tests. 81 # 82 # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix 83 # host gateway host 84 # 85 # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description 86 # Displays test result and returns success or failure. 87 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 91 # bar in bar-ns). 92 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 1 103 104 echo 1 | ip netns exec router-ns tee /proc/sys/net/ipv4/ip_forward 105 106 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 1 110 111 nettest -B -N bar-ns -O foo-ns -r $1 || return 1 112 nettest -B -N foo-ns -O bar-ns -r $4 || return 1 113 114 return 0 115} 116 117segmenttest(){ 118 # Sets up veth link and tries to connect over it. 119 # Arguments: ip_a ip_b prefix_len test_description 120 hide_output 121 ip netns add foo-ns 122 ip netns add bar-ns 123 ip link add foo netns foo-ns type veth peer name bar netns bar-ns 124 125 test_result=0 126 _do_segmenttest "$@" || test_result=1 127 128 ip netns pids foo-ns | xargs -r kill -9 129 ip netns pids bar-ns | xargs -r kill -9 130 ip netns del foo-ns 131 ip netns del bar-ns 132 show_output 133 134 # inverted tests will expect failure instead of success 135 [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result` 136 137 show_result $test_result "$4" 138} 139 140route_test(){ 141 # Sets up a simple gateway and tries to connect through it. 142 # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix 143 # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description 144 # Returns success or failure. 145 146 hide_output 147 ip netns add foo-ns 148 ip netns add bar-ns 149 ip netns add router-ns 150 ip link add foo netns foo-ns type veth peer name foo1 netns router-ns 151 ip link add bar netns bar-ns type veth peer name bar1 netns router-ns 152 153 test_result=0 154 _do_route_test "$@" || test_result=1 155 156 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 -9 159 ip netns del foo-ns 160 ip netns del bar-ns 161 ip netns del router-ns 162 163 show_output 164 165 # inverted tests will expect failure instead of success 166 [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result` 167 show_result $test_result "$6" 168} 169 170echo "###########################################################################" 171echo "Unicast address extensions tests (behavior of reserved IPv4 addresses)" 172echo "###########################################################################" 173# 174# Test support for 240/4 175segmenttest 240.1.2.1 240.1.2.4 24 "assign and ping within 240/4 (1 of 2) (is allowed)" 176segmenttest 250.100.2.1 250.100.30.4 16 "assign and ping within 240/4 (2 of 2) (is allowed)" 177# 178# Test support for 0/8 179segmenttest 0.1.2.17 0.1.2.23 24 "assign and ping within 0/8 (1 of 2) (is allowed)" 180segmenttest 0.77.240.17 0.77.2.23 16 "assign and ping within 0/8 (2 of 2) (is allowed)" 181# 182# Even 255.255/16 is OK! 183segmenttest 255.255.3.1 255.255.50.77 16 "assign and ping inside 255.255/16 (is allowed)" 184# 185# Or 255.255.255/24 186segmenttest 255.255.255.1 255.255.255.254 24 "assign and ping inside 255.255.255/24 (is allowed)" 187# 188# Routing between different networks 189route_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)" 190route_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)" 191# 192# ============================================== 193# ==== TESTS THAT CURRENTLY EXPECT FAILURE ===== 194# ============================================== 195expect_failure=true 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. 198segmenttest 0.0.1.5 0.0.0.0 16 "assigning 0.0.0.0 (is forbidden)" 199segmenttest 255.255.255.1 255.255.255.255 16 "assigning 255.255.255.255 (is forbidden)" 200# 201# Test support for not having all of 127 be loopback 202# Currently Linux does not allow this, so this should fail too 203segmenttest 127.99.4.5 127.99.4.6 16 "assign and ping inside 127/8 (is forbidden)" 204# 205# Test support for lowest address 206# Currently Linux does not allow this, so this should fail too 207segmenttest 5.10.15.20 5.10.15.0 24 "assign and ping lowest address (is forbidden)" 208# 209# Routing using lowest address as a gateway/endpoint 210# Currently Linux does not allow this, so this should fail too 211route_test 192.168.42.1 192.168.42.0 9.8.7.6 9.8.7.0 24 "routing using lowest address (is forbidden)" 212# 213# Test support for unicast use of class D 214# Currently Linux does not allow this, so this should fail too 215segmenttest 225.1.2.3 225.1.2.200 24 "assign and ping class D address (is forbidden)" 216# 217# Routing using class D as a gateway 218route_test 225.1.42.1 225.1.42.2 9.8.7.6 9.8.7.1 24 "routing using class D (is forbidden)" 219# 220# Routing using 127/8 221# Currently Linux does not allow this, so this should fail too 222route_test 127.99.2.3 127.99.2.4 200.1.2.3 200.1.2.4 24 "routing using 127/8 (is forbidden)" 223# 224unset expect_failure 225# ===================================================== 226# ==== END OF TESTS THAT CURRENTLY EXPECT FAILURE ===== 227# ===================================================== 228exit ${result} 229