From: Florian Westphal Add a dedicated test to exercise conntrack clash resolution path. Test program emits 128 identical udp packets in parallel, then reads back replies from socat echo server. Also check (via conntrack -S) that the clash path was hit at least once. Due to the racy nature of the test its possible that despite the threaded program all packets were processed in-order or on same cpu, emit a SKIP warning in this case. Two tests are added: - one to test the simpler, non-nat case - one to exercise clash resolution where packets might have different nat transformations attached to them. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- .../selftests/net/netfilter/.gitignore | 1 + .../testing/selftests/net/netfilter/Makefile | 3 + .../net/netfilter/conntrack_clash.sh | 175 ++++++++++++++++++ .../selftests/net/netfilter/udpclash.c | 158 ++++++++++++++++ 4 files changed, 337 insertions(+) create mode 100755 tools/testing/selftests/net/netfilter/conntrack_clash.sh create mode 100644 tools/testing/selftests/net/netfilter/udpclash.c diff --git a/tools/testing/selftests/net/netfilter/.gitignore b/tools/testing/selftests/net/netfilter/.gitignore index 64c4f8d9aa6c..5d2be9a00627 100644 --- a/tools/testing/selftests/net/netfilter/.gitignore +++ b/tools/testing/selftests/net/netfilter/.gitignore @@ -5,3 +5,4 @@ conntrack_dump_flush conntrack_reverse_clash sctp_collision nf_queue +udpclash diff --git a/tools/testing/selftests/net/netfilter/Makefile b/tools/testing/selftests/net/netfilter/Makefile index e9b2f553588d..a98ed892f55f 100644 --- a/tools/testing/selftests/net/netfilter/Makefile +++ b/tools/testing/selftests/net/netfilter/Makefile @@ -15,6 +15,7 @@ TEST_PROGS += conntrack_tcp_unreplied.sh TEST_PROGS += conntrack_resize.sh TEST_PROGS += conntrack_sctp_collision.sh TEST_PROGS += conntrack_vrf.sh +TEST_PROGS += conntrack_clash.sh TEST_PROGS += conntrack_reverse_clash.sh TEST_PROGS += ipvs.sh TEST_PROGS += nf_conntrack_packetdrill.sh @@ -44,6 +45,7 @@ TEST_GEN_FILES += connect_close nf_queue TEST_GEN_FILES += conntrack_dump_flush TEST_GEN_FILES += conntrack_reverse_clash TEST_GEN_FILES += sctp_collision +TEST_GEN_FILES += udpclash include ../../lib.mk @@ -52,6 +54,7 @@ $(OUTPUT)/nf_queue: LDLIBS += $(MNL_LDLIBS) $(OUTPUT)/conntrack_dump_flush: CFLAGS += $(MNL_CFLAGS) $(OUTPUT)/conntrack_dump_flush: LDLIBS += $(MNL_LDLIBS) +$(OUTPUT)/udpclash: LDLIBS += -lpthread TEST_FILES := lib.sh TEST_FILES += packetdrill diff --git a/tools/testing/selftests/net/netfilter/conntrack_clash.sh b/tools/testing/selftests/net/netfilter/conntrack_clash.sh new file mode 100755 index 000000000000..3712c1b9b38b --- /dev/null +++ b/tools/testing/selftests/net/netfilter/conntrack_clash.sh @@ -0,0 +1,175 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +source lib.sh + +clash_resolution_active=0 +dport=22111 +ret=0 + +cleanup() +{ + # netns cleanup also zaps any remaining socat echo server. + cleanup_all_ns +} + +checktool "nft --version" "run test without nft" +checktool "conntrack --version" "run test without conntrack" +checktool "socat -h" "run test without socat" + +trap cleanup EXIT + +setup_ns nsclient1 nsclient2 nsrouter + +ip netns exec "$nsrouter" nft -f -</dev/null & + done + + for port in $ports; do + wait_local_port_listen "$ns" $port udp + done +} + +add_addr() +{ + local ns="$1" + local dev="$2" + local i="$3" + local j="$4" + + ip -net "$ns" link set "$dev" up + ip -net "$ns" addr add "10.0.$i.$j/24" dev "$dev" +} + +ping_test() +{ + local ns="$1" + local daddr="$2" + + if ! ip netns exec "$ns" ping -q -c 1 $daddr > /dev/null;then + echo "FAIL: ping from $ns to $daddr" + exit 1 + fi +} + +run_one_clash_test() +{ + local ns="$1" + local daddr="$2" + local dport="$3" + local entries + local cre + + if ! ip netns exec "$ns" ./udpclash $daddr $dport;then + echo "FAIL: did not receive expected number of replies for $daddr:$dport" + ret=1 + return 1 + fi + + entries=$(conntrack -S | wc -l) + cre=$(conntrack -S | grep -v "clash_resolve=0" | wc -l) + + if [ "$cre" -ne "$entries" ] ;then + clash_resolution_active=1 + return 0 + fi + + # 1 cpu -> parallel insertion impossible + if [ "$entries" -eq 1 ]; then + return 0 + fi + + # not a failure: clash resolution logic did not trigger, but all replies + # were received. With right timing, xmit completed sequentially and + # no parallel insertion occurs. + return $ksft_skip +} + +run_clash_test() +{ + local ns="$1" + local daddr="$2" + local dport="$3" + + for i in $(seq 1 10);do + run_one_clash_test "$ns" "$daddr" "$dport" + local rv=$? + if [ $rv -eq 0 ];then + echo "PASS: clash resolution test for $daddr:$dport on attempt $i" + return 0 + elif [ $rv -eq 1 ];then + echo "FAIL: clash resolution test for $daddr:$dport on attempt $i" + return 1 + fi + done +} + +ip link add veth0 netns "$nsclient1" type veth peer name veth0 netns "$nsrouter" +ip link add veth0 netns "$nsclient2" type veth peer name veth1 netns "$nsrouter" +add_addr "$nsclient1" veth0 1 1 +add_addr "$nsclient2" veth0 2 1 +add_addr "$nsrouter" veth0 1 99 +add_addr "$nsrouter" veth1 2 99 + +ip -net "$nsclient1" route add default via 10.0.1.99 +ip -net "$nsclient2" route add default via 10.0.2.99 +ip netns exec "$nsrouter" sysctl -q net.ipv4.ip_forward=1 + +ping_test "$nsclient1" 10.0.1.99 +ping_test "$nsclient1" 10.0.2.1 +ping_test "$nsclient2" 10.0.1.1 + +spawn_servers "$nsclient2" + +# exercise clash resolution with nat: +# nsrouter is supposed to dnat to 10.0.2.1:900{0,1,2,3}. +run_clash_test "$nsclient1" 10.0.1.99 "$dport" + +# exercise clash resolution without nat. +load_simple_ruleset "$nsclient2" +run_clash_test "$nsclient2" 127.0.0.1 9001 + +if [ $clash_resolution_active -eq 0 ];then + [ "$ret" -eq 0 ] && ret=$ksft_skip + echo "SKIP: Clash resolution did not trigger" +fi + +exit $ret diff --git a/tools/testing/selftests/net/netfilter/udpclash.c b/tools/testing/selftests/net/netfilter/udpclash.c new file mode 100644 index 000000000000..85c7b906ad08 --- /dev/null +++ b/tools/testing/selftests/net/netfilter/udpclash.c @@ -0,0 +1,158 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* Usage: ./udpclash + * + * Emit THREAD_COUNT UDP packets sharing the same saddr:daddr pair. + * + * This mimics DNS resolver libraries that emit A and AAAA requests + * in parallel. + * + * This exercises conntrack clash resolution logic added and later + * refined in + * + * 71d8c47fc653 ("netfilter: conntrack: introduce clash resolution on insertion race") + * ed07d9a021df ("netfilter: nf_conntrack: resolve clash for matching conntracks") + * 6a757c07e51f ("netfilter: conntrack: allow insertion of clashing entries") + */ +#include +#include +#include +#include +#include +#include +#include + +#define THREAD_COUNT 128 + +struct thread_args { + const struct sockaddr_in *si_remote; + int sockfd; +}; + +static int wait = 1; + +static void *thread_main(void *varg) +{ + const struct sockaddr_in *si_remote; + const struct thread_args *args = varg; + static const char msg[] = "foo"; + + si_remote = args->si_remote; + + while (wait == 1) + ; + + if (sendto(args->sockfd, msg, strlen(msg), MSG_NOSIGNAL, + (struct sockaddr *)si_remote, sizeof(*si_remote)) < 0) + exit(111); + + return varg; +} + +static int run_test(int fd, const struct sockaddr_in *si_remote) +{ + struct thread_args thread_args = { + .si_remote = si_remote, + .sockfd = fd, + }; + pthread_t *tid = calloc(THREAD_COUNT, sizeof(pthread_t)); + unsigned int repl_count = 0, timeout = 0; + int i; + + if (!tid) { + perror("calloc"); + return 1; + } + + for (i = 0; i < THREAD_COUNT; i++) { + int err = pthread_create(&tid[i], NULL, &thread_main, &thread_args); + + if (err != 0) { + perror("pthread_create"); + exit(1); + } + } + + wait = 0; + + for (i = 0; i < THREAD_COUNT; i++) + pthread_join(tid[i], NULL); + + while (repl_count < THREAD_COUNT) { + struct sockaddr_in si_repl; + socklen_t si_repl_len = sizeof(si_repl); + char repl[512]; + ssize_t ret; + + ret = recvfrom(fd, repl, sizeof(repl), MSG_NOSIGNAL, + (struct sockaddr *) &si_repl, &si_repl_len); + if (ret < 0) { + if (timeout++ > 5000) { + fputs("timed out while waiting for reply from thread\n", stderr); + break; + } + + /* give reply time to pass though the stack */ + usleep(1000); + continue; + } + + if (si_repl_len != sizeof(*si_remote)) { + fprintf(stderr, "warning: reply has unexpected repl_len %d vs %d\n", + (int)si_repl_len, (int)sizeof(si_repl)); + } else if (si_remote->sin_addr.s_addr != si_repl.sin_addr.s_addr || + si_remote->sin_port != si_repl.sin_port) { + char a[64], b[64]; + + inet_ntop(AF_INET, &si_remote->sin_addr, a, sizeof(a)); + inet_ntop(AF_INET, &si_repl.sin_addr, b, sizeof(b)); + + fprintf(stderr, "reply from wrong source: want %s:%d got %s:%d\n", + a, ntohs(si_remote->sin_port), b, ntohs(si_repl.sin_port)); + } + + repl_count++; + } + + printf("got %d of %d replies\n", repl_count, THREAD_COUNT); + + free(tid); + + return repl_count == THREAD_COUNT ? 0 : 1; +} + +int main(int argc, char *argv[]) +{ + struct sockaddr_in si_local = { + .sin_family = AF_INET, + }; + struct sockaddr_in si_remote = { + .sin_family = AF_INET, + }; + int fd, ret; + + if (argc < 3) { + fputs("Usage: send_udp \n", stderr); + return 1; + } + + si_remote.sin_port = htons(atoi(argv[2])); + si_remote.sin_addr.s_addr = inet_addr(argv[1]); + + fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_UDP); + if (fd < 0) { + perror("socket"); + return 1; + } + + if (bind(fd, (struct sockaddr *)&si_local, sizeof(si_local)) < 0) { + perror("bind"); + return 1; + } + + ret = run_test(fd, &si_remote); + + close(fd); + + return ret; +} -- 2.39.5