1#!/bin/bash 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 31source lib.sh 32 33# nettest can be run from PATH or from same directory as this selftest 34if ! which nettest >/dev/null; then 35 PATH=$PWD:$PATH 36 if ! which nettest >/dev/null; then 37 echo "'nettest' command not found; skipping tests" 38 exit $ksft_skip 39 fi 40fi 41 42result=0 43 44hide_output(){ exec 3>&1 4>&2 >/dev/null 2>/dev/null; } 45show_output(){ exec >&3 2>&4; } 46 47show_result(){ 48 if [ $1 -eq 0 ]; then 49 printf "TEST: %-60s [ OK ]\n" "${2}" 50 else 51 printf "TEST: %-60s [FAIL]\n" "${2}" 52 result=1 53 fi 54} 55 56_do_segmenttest(){ 57 # Perform a simple set of link tests between a pair of 58 # IP addresses on a shared (virtual) segment, using 59 # ping and nettest. 60 # foo --- bar 61 # Arguments: ip_a ip_b prefix_length test_description 62 # 63 # Caller must set up $foo_ns and $bar_ns namespaces 64 # containing linked veth devices foo and bar, 65 # respectively. 66 67 ip -n $foo_ns address add $1/$3 dev foo || return 1 68 ip -n $foo_ns link set foo up || return 1 69 ip -n $bar_ns address add $2/$3 dev bar || return 1 70 ip -n $bar_ns link set bar up || return 1 71 72 ip netns exec $foo_ns timeout 2 ping -c 1 $2 || return 1 73 ip netns exec $bar_ns timeout 2 ping -c 1 $1 || return 1 74 75 nettest -B -N $bar_ns -O $foo_ns -r $1 || return 1 76 nettest -B -N $foo_ns -O $bar_ns -r $2 || return 1 77 78 return 0 79} 80 81_do_route_test(){ 82 # Perform a simple set of gateway tests. 83 # 84 # [foo] <---> [foo1]-[bar1] <---> [bar] /prefix 85 # host gateway host 86 # 87 # Arguments: foo_ip foo1_ip bar1_ip bar_ip prefix_len test_description 88 # Displays test result and returns success or failure. 89 90 # Caller must set up $foo_ns, $bar_ns, and $router_ns 91 # containing linked veth devices foo-foo1, bar1-bar 92 # (foo in $foo_ns, foo1 and bar1 in $router_ns, and 93 # bar in $bar_ns). 94 95 ip -n $foo_ns address add $1/$5 dev foo || return 1 96 ip -n $foo_ns link set foo up || return 1 97 ip -n $foo_ns route add default via $2 || return 1 98 ip -n $bar_ns address add $4/$5 dev bar || return 1 99 ip -n $bar_ns link set bar up || return 1 100 ip -n $bar_ns route add default via $3 || return 1 101 ip -n $router_ns address add $2/$5 dev foo1 || return 1 102 ip -n $router_ns link set foo1 up || return 1 103 ip -n $router_ns address add $3/$5 dev bar1 || return 1 104 ip -n $router_ns link set bar1 up || return 1 105 106 echo 1 | ip netns exec $router_ns tee /proc/sys/net/ipv4/ip_forward 107 108 ip netns exec $foo_ns timeout 2 ping -c 1 $2 || return 1 109 ip netns exec $foo_ns timeout 2 ping -c 1 $4 || return 1 110 ip netns exec $bar_ns timeout 2 ping -c 1 $3 || return 1 111 ip netns exec $bar_ns timeout 2 ping -c 1 $1 || return 1 112 113 nettest -B -N $bar_ns -O $foo_ns -r $1 || return 1 114 nettest -B -N $foo_ns -O $bar_ns -r $4 || return 1 115 116 return 0 117} 118 119segmenttest(){ 120 # Sets up veth link and tries to connect over it. 121 # Arguments: ip_a ip_b prefix_len test_description 122 hide_output 123 setup_ns foo_ns bar_ns 124 ip link add foo netns $foo_ns type veth peer name bar netns $bar_ns 125 126 test_result=0 127 _do_segmenttest "$@" || test_result=1 128 129 ip netns pids $foo_ns | xargs -r kill -9 130 ip netns pids $bar_ns | xargs -r kill -9 131 cleanup_ns $foo_ns $bar_ns 132 show_output 133 134 # inverted tests will expect failure instead of success 135 [ -n "$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 setup_ns foo_ns bar_ns router_ns 148 ip link add foo netns $foo_ns type veth peer name foo1 netns $router_ns 149 ip link add bar netns $bar_ns type veth peer name bar1 netns $router_ns 150 151 test_result=0 152 _do_route_test "$@" || test_result=1 153 154 ip netns pids $foo_ns | xargs -r kill -9 155 ip netns pids $bar_ns | xargs -r kill -9 156 ip netns pids $router_ns | xargs -r kill -9 157 cleanup_ns $foo_ns $bar_ns $router_ns 158 159 show_output 160 161 # inverted tests will expect failure instead of success 162 [ -n "$expect_failure" ] && test_result=`expr 1 - $test_result` 163 show_result $test_result "$6" 164} 165 166echo "###########################################################################" 167echo "Unicast address extensions tests (behavior of reserved IPv4 addresses)" 168echo "###########################################################################" 169# 170# Test support for 240/4 171segmenttest 240.1.2.1 240.1.2.4 24 "assign and ping within 240/4 (1 of 2) (is allowed)" 172segmenttest 250.100.2.1 250.100.30.4 16 "assign and ping within 240/4 (2 of 2) (is allowed)" 173# 174# Test support for 0/8 175segmenttest 0.1.2.17 0.1.2.23 24 "assign and ping within 0/8 (1 of 2) (is allowed)" 176segmenttest 0.77.240.17 0.77.2.23 16 "assign and ping within 0/8 (2 of 2) (is allowed)" 177# 178# Even 255.255/16 is OK! 179segmenttest 255.255.3.1 255.255.50.77 16 "assign and ping inside 255.255/16 (is allowed)" 180# 181# Or 255.255.255/24 182segmenttest 255.255.255.1 255.255.255.254 24 "assign and ping inside 255.255.255/24 (is allowed)" 183# 184# Routing between different networks 185route_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)" 186route_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)" 187# 188# Test support for lowest address ending in .0 189segmenttest 5.10.15.20 5.10.15.0 24 "assign and ping lowest address (/24)" 190# 191# Test support for lowest address not ending in .0 192segmenttest 192.168.101.192 192.168.101.193 26 "assign and ping lowest address (/26)" 193# 194# Routing using lowest address as a gateway/endpoint 195route_test 192.168.42.1 192.168.42.0 9.8.7.6 9.8.7.0 24 "routing using lowest address" 196# 197# ============================================== 198# ==== TESTS THAT CURRENTLY EXPECT FAILURE ===== 199# ============================================== 200expect_failure=true 201# It should still not be possible to use 0.0.0.0 or 255.255.255.255 202# as a unicast address. Thus, these tests expect failure. 203segmenttest 0.0.1.5 0.0.0.0 16 "assigning 0.0.0.0 (is forbidden)" 204segmenttest 255.255.255.1 255.255.255.255 16 "assigning 255.255.255.255 (is forbidden)" 205# 206# Test support for not having all of 127 be loopback 207# Currently Linux does not allow this, so this should fail too 208segmenttest 127.99.4.5 127.99.4.6 16 "assign and ping inside 127/8 (is forbidden)" 209# 210# Test support for unicast use of class D 211# Currently Linux does not allow this, so this should fail too 212segmenttest 225.1.2.3 225.1.2.200 24 "assign and ping class D address (is forbidden)" 213# 214# Routing using class D as a gateway 215route_test 225.1.42.1 225.1.42.2 9.8.7.6 9.8.7.1 24 "routing using class D (is forbidden)" 216# 217# Routing using 127/8 218# Currently Linux does not allow this, so this should fail too 219route_test 127.99.2.3 127.99.2.4 200.1.2.3 200.1.2.4 24 "routing using 127/8 (is forbidden)" 220# 221unset expect_failure 222# ===================================================== 223# ==== END OF TESTS THAT CURRENTLY EXPECT FAILURE ===== 224# ===================================================== 225exit ${result} 226