name : unicast_extensions.sh #!/bin/bash # 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. source lib.sh # 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 $ksft_skip 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 setup_ns foo_ns 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 cleanup_ns $foo_ns $bar_ns show_output # inverted tests will expect failure instead of success [ -n "$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 setup_ns foo_ns bar_ns 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 cleanup_ns $foo_ns $bar_ns $router_ns show_output # inverted tests will expect failure instead of success [ -n "$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)" # # Test support for lowest address ending in .0 segmenttest 5.10.15.20 5.10.15.0 24 "assign and ping lowest address (/24)" # # Test support for lowest address not ending in .0 segmenttest 192.168.101.192 192.168.101.193 26 "assign and ping lowest address (/26)" # # Routing using lowest address as a gateway/endpoint route_test 192.168.42.1 192.168.42.0 9.8.7.6 9.8.7.0 24 "routing using lowest address" # # ============================================== # ==== 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 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}