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| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2024-01-15 12:55:14 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-01-23 14:40:24 -0800 |
| commit | a74712241b4675175cd8e3310fa206d8756ad5a1 (patch) | |
| tree | e9af2ccb810881632330d014ecc83b1726537a16 /tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c | |
| parent | e472f88891abbc535a5e16a68a104073985f6061 (diff) | |
| download | lwn-a74712241b4675175cd8e3310fa206d8756ad5a1.tar.gz lwn-a74712241b4675175cd8e3310fa206d8756ad5a1.zip | |
selftest: bpf: Test bpf_sk_assign_tcp_reqsk().
This commit adds a sample selftest to demonstrate how we can use
bpf_sk_assign_tcp_reqsk() as the backend of SYN Proxy.
The test creates IPv4/IPv6 x TCP connections and transfer messages
over them on lo with BPF tc prog attached.
The tc prog will process SYN and returns SYN+ACK with the following
ISN and TS. In a real use case, this part will be done by other
hosts.
MSB LSB
ISN: | 31 ... 8 | 7 6 | 5 | 4 | 3 2 1 0 |
| Hash_1 | MSS | ECN | SACK | WScale |
TS: | 31 ... 8 | 7 ... 0 |
| Random | Hash_2 |
WScale in SYN is reused in SYN+ACK.
The client returns ACK, and tc prog will recalculate ISN and TS
from ACK and validate SYN Cookie.
If it's valid, the prog calls kfunc to allocate a reqsk for skb and
configure the reqsk based on the argument created from SYN Cookie.
Later, the reqsk will be processed in cookie_v[46]_check() to create
a connection.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240115205514.68364-7-kuniyu@amazon.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c')
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c b/tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c new file mode 100644 index 000000000000..eaf441dc7e79 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/tcp_custom_syncookie.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright Amazon.com Inc. or its affiliates. */ + +#define _GNU_SOURCE +#include <sched.h> +#include <stdlib.h> +#include <net/if.h> + +#include "test_progs.h" +#include "cgroup_helpers.h" +#include "network_helpers.h" +#include "test_tcp_custom_syncookie.skel.h" + +static struct test_tcp_custom_syncookie_case { + int family, type; + char addr[16]; + char name[10]; +} test_cases[] = { + { + .name = "IPv4 TCP", + .family = AF_INET, + .type = SOCK_STREAM, + .addr = "127.0.0.1", + }, + { + .name = "IPv6 TCP", + .family = AF_INET6, + .type = SOCK_STREAM, + .addr = "::1", + }, +}; + +static int setup_netns(void) +{ + if (!ASSERT_OK(unshare(CLONE_NEWNET), "create netns")) + return -1; + + if (!ASSERT_OK(system("ip link set dev lo up"), "ip")) + goto err; + + if (!ASSERT_OK(write_sysctl("/proc/sys/net/ipv4/tcp_ecn", "1"), + "write_sysctl")) + goto err; + + return 0; +err: + return -1; +} + +static int setup_tc(struct test_tcp_custom_syncookie *skel) +{ + LIBBPF_OPTS(bpf_tc_hook, qdisc_lo, .attach_point = BPF_TC_INGRESS); + LIBBPF_OPTS(bpf_tc_opts, tc_attach, + .prog_fd = bpf_program__fd(skel->progs.tcp_custom_syncookie)); + + qdisc_lo.ifindex = if_nametoindex("lo"); + if (!ASSERT_OK(bpf_tc_hook_create(&qdisc_lo), "qdisc add dev lo clsact")) + goto err; + + if (!ASSERT_OK(bpf_tc_attach(&qdisc_lo, &tc_attach), + "filter add dev lo ingress")) + goto err; + + return 0; +err: + return -1; +} + +#define msg "Hello World" +#define msglen 11 + +static void transfer_message(int sender, int receiver) +{ + char buf[msglen]; + int ret; + + ret = send(sender, msg, msglen, 0); + if (!ASSERT_EQ(ret, msglen, "send")) + return; + + memset(buf, 0, sizeof(buf)); + + ret = recv(receiver, buf, msglen, 0); + if (!ASSERT_EQ(ret, msglen, "recv")) + return; + + ret = strncmp(buf, msg, msglen); + if (!ASSERT_EQ(ret, 0, "strncmp")) + return; +} + +static void create_connection(struct test_tcp_custom_syncookie_case *test_case) +{ + int server, client, child; + + server = start_server(test_case->family, test_case->type, test_case->addr, 0, 0); + if (!ASSERT_NEQ(server, -1, "start_server")) + return; + + client = connect_to_fd(server, 0); + if (!ASSERT_NEQ(client, -1, "connect_to_fd")) + goto close_server; + + child = accept(server, NULL, 0); + if (!ASSERT_NEQ(child, -1, "accept")) + goto close_client; + + transfer_message(client, child); + transfer_message(child, client); + + close(child); +close_client: + close(client); +close_server: + close(server); +} + +void test_tcp_custom_syncookie(void) +{ + struct test_tcp_custom_syncookie *skel; + int i; + + if (setup_netns()) + return; + + skel = test_tcp_custom_syncookie__open_and_load(); + if (!ASSERT_OK_PTR(skel, "open_and_load")) + return; + + if (setup_tc(skel)) + goto destroy_skel; + + for (i = 0; i < ARRAY_SIZE(test_cases); i++) { + if (!test__start_subtest(test_cases[i].name)) + continue; + + skel->bss->handled_syn = false; + skel->bss->handled_ack = false; + + create_connection(&test_cases[i]); + + ASSERT_EQ(skel->bss->handled_syn, true, "SYN is not handled at tc."); + ASSERT_EQ(skel->bss->handled_ack, true, "ACK is not handled at tc"); + } + +destroy_skel: + system("tc qdisc del dev lo clsact"); + + test_tcp_custom_syncookie__destroy(skel); +} |