From 435f90a338ae42c0d7c0109a1742d1b16bc99bf6 Mon Sep 17 00:00:00 2001 From: Sowmini Varadhan Date: Wed, 7 Nov 2018 16:12:02 -0800 Subject: [PATCH] selftests/bpf: add a test case for sock_ops perf-event notification This patch provides a tcp_bpf based eBPF sample. The test - ncat(1) as the TCP client program to connect() to a port with the intention of triggerring SYN retransmissions: we first install an iptables DROP rule to make sure ncat SYNs are resent (instead of aborting instantly after a TCP RST) - has a bpf kernel module that sends a perf-event notification for each TCP retransmit, and also tracks the number of such notifications sent in the global_map The test passes when the number of event notifications intercepted in user-space matches the value in the global_map. Signed-off-by: Sowmini Varadhan Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/Makefile | 4 +- tools/testing/selftests/bpf/test_tcpnotify.h | 19 ++ .../selftests/bpf/test_tcpnotify_kern.c | 95 +++++++++ .../selftests/bpf/test_tcpnotify_user.c | 186 ++++++++++++++++++ 4 files changed, 303 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/test_tcpnotify.h create mode 100644 tools/testing/selftests/bpf/test_tcpnotify_kern.c create mode 100644 tools/testing/selftests/bpf/test_tcpnotify_user.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index ecd79b7fb107..57b4712a6276 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -24,12 +24,13 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \ test_sock test_btf test_sockmap test_lirc_mode2_user get_cgroup_id_user \ test_socket_cookie test_cgroup_storage test_select_reuseport test_section_names \ - test_netcnt + test_netcnt test_tcpnotify_user TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \ test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \ sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o test_tracepoint.o \ test_l4lb_noinline.o test_xdp_noinline.o test_stacktrace_map.o \ + test_tcpnotify_kern.o \ sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o \ sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \ test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \ @@ -74,6 +75,7 @@ $(OUTPUT)/test_sock_addr: cgroup_helpers.c $(OUTPUT)/test_socket_cookie: cgroup_helpers.c $(OUTPUT)/test_sockmap: cgroup_helpers.c $(OUTPUT)/test_tcpbpf_user: cgroup_helpers.c +$(OUTPUT)/test_tcpnotify_user: cgroup_helpers.c trace_helpers.c $(OUTPUT)/test_progs: trace_helpers.c $(OUTPUT)/get_cgroup_id_user: cgroup_helpers.c $(OUTPUT)/test_cgroup_storage: cgroup_helpers.c diff --git a/tools/testing/selftests/bpf/test_tcpnotify.h b/tools/testing/selftests/bpf/test_tcpnotify.h new file mode 100644 index 000000000000..8b6cea030bfc --- /dev/null +++ b/tools/testing/selftests/bpf/test_tcpnotify.h @@ -0,0 +1,19 @@ +// SPDX-License-Identifier: GPL-2.0 + +#ifndef _TEST_TCPBPF_H +#define _TEST_TCPBPF_H + +struct tcpnotify_globals { + __u32 total_retrans; + __u32 ncalls; +}; + +struct tcp_notifier { + __u8 type; + __u8 subtype; + __u8 source; + __u8 hash; +}; + +#define TESTPORT 12877 +#endif diff --git a/tools/testing/selftests/bpf/test_tcpnotify_kern.c b/tools/testing/selftests/bpf/test_tcpnotify_kern.c new file mode 100644 index 000000000000..edbca203ce2d --- /dev/null +++ b/tools/testing/selftests/bpf/test_tcpnotify_kern.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "bpf_helpers.h" +#include "bpf_endian.h" +#include "test_tcpnotify.h" + +struct bpf_map_def SEC("maps") global_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(struct tcpnotify_globals), + .max_entries = 4, +}; + +struct bpf_map_def SEC("maps") perf_event_map = { + .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, + .key_size = sizeof(int), + .value_size = sizeof(__u32), + .max_entries = 2, +}; + +int _version SEC("version") = 1; + +SEC("sockops") +int bpf_testcb(struct bpf_sock_ops *skops) +{ + int rv = -1; + int op; + + op = (int) skops->op; + + if (bpf_ntohl(skops->remote_port) != TESTPORT) { + skops->reply = -1; + return 0; + } + + switch (op) { + case BPF_SOCK_OPS_TIMEOUT_INIT: + case BPF_SOCK_OPS_RWND_INIT: + case BPF_SOCK_OPS_NEEDS_ECN: + case BPF_SOCK_OPS_BASE_RTT: + case BPF_SOCK_OPS_RTO_CB: + rv = 1; + break; + + case BPF_SOCK_OPS_TCP_CONNECT_CB: + case BPF_SOCK_OPS_TCP_LISTEN_CB: + case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + bpf_sock_ops_cb_flags_set(skops, (BPF_SOCK_OPS_RETRANS_CB_FLAG| + BPF_SOCK_OPS_RTO_CB_FLAG)); + rv = 1; + break; + case BPF_SOCK_OPS_RETRANS_CB: { + __u32 key = 0; + struct tcpnotify_globals g, *gp; + struct tcp_notifier msg = { + .type = 0xde, + .subtype = 0xad, + .source = 0xbe, + .hash = 0xef, + }; + + rv = 1; + + /* Update results */ + gp = bpf_map_lookup_elem(&global_map, &key); + if (!gp) + break; + g = *gp; + g.total_retrans = skops->total_retrans; + g.ncalls++; + bpf_map_update_elem(&global_map, &key, &g, + BPF_ANY); + bpf_perf_event_output(skops, &perf_event_map, + BPF_F_CURRENT_CPU, + &msg, sizeof(msg)); + } + break; + default: + rv = -1; + } + skops->reply = rv; + return 1; +} +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/test_tcpnotify_user.c b/tools/testing/selftests/bpf/test_tcpnotify_user.c new file mode 100644 index 000000000000..ff3c4522aed6 --- /dev/null +++ b/tools/testing/selftests/bpf/test_tcpnotify_user.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "bpf_rlimit.h" +#include "bpf_util.h" +#include "cgroup_helpers.h" + +#include "test_tcpnotify.h" +#include "trace_helpers.h" + +#define SOCKET_BUFFER_SIZE (getpagesize() < 8192L ? getpagesize() : 8192L) + +pthread_t tid; +int rx_callbacks; + +static int dummyfn(void *data, int size) +{ + struct tcp_notifier *t = data; + + if (t->type != 0xde || t->subtype != 0xad || + t->source != 0xbe || t->hash != 0xef) + return 1; + rx_callbacks++; + return 0; +} + +void tcp_notifier_poller(int fd) +{ + while (1) + perf_event_poller(fd, dummyfn); +} + +static void *poller_thread(void *arg) +{ + int fd = *(int *)arg; + + tcp_notifier_poller(fd); + return arg; +} + +int verify_result(const struct tcpnotify_globals *result) +{ + return (result->ncalls > 0 && result->ncalls == rx_callbacks ? 0 : 1); +} + +static int bpf_find_map(const char *test, struct bpf_object *obj, + const char *name) +{ + struct bpf_map *map; + + map = bpf_object__find_map_by_name(obj, name); + if (!map) { + printf("%s:FAIL:map '%s' not found\n", test, name); + return -1; + } + return bpf_map__fd(map); +} + +static int setup_bpf_perf_event(int mapfd) +{ + struct perf_event_attr attr = { + .sample_type = PERF_SAMPLE_RAW, + .type = PERF_TYPE_SOFTWARE, + .config = PERF_COUNT_SW_BPF_OUTPUT, + }; + int key = 0; + int pmu_fd; + + pmu_fd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, 0); + if (pmu_fd < 0) + return pmu_fd; + bpf_map_update_elem(mapfd, &key, &pmu_fd, BPF_ANY); + + ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); + return pmu_fd; +} + +int main(int argc, char **argv) +{ + const char *file = "test_tcpnotify_kern.o"; + int prog_fd, map_fd, perf_event_fd; + struct tcpnotify_globals g = {0}; + const char *cg_path = "/foo"; + int error = EXIT_FAILURE; + struct bpf_object *obj; + int cg_fd = -1; + __u32 key = 0; + int rv; + char test_script[80]; + int pmu_fd; + cpu_set_t cpuset; + + CPU_ZERO(&cpuset); + CPU_SET(0, &cpuset); + pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset); + + if (setup_cgroup_environment()) + goto err; + + cg_fd = create_and_get_cgroup(cg_path); + if (!cg_fd) + goto err; + + if (join_cgroup(cg_path)) + goto err; + + if (bpf_prog_load(file, BPF_PROG_TYPE_SOCK_OPS, &obj, &prog_fd)) { + printf("FAILED: load_bpf_file failed for: %s\n", file); + goto err; + } + + rv = bpf_prog_attach(prog_fd, cg_fd, BPF_CGROUP_SOCK_OPS, 0); + if (rv) { + printf("FAILED: bpf_prog_attach: %d (%s)\n", + error, strerror(errno)); + goto err; + } + + perf_event_fd = bpf_find_map(__func__, obj, "perf_event_map"); + if (perf_event_fd < 0) + goto err; + + map_fd = bpf_find_map(__func__, obj, "global_map"); + if (map_fd < 0) + goto err; + + pmu_fd = setup_bpf_perf_event(perf_event_fd); + if (pmu_fd < 0 || perf_event_mmap(pmu_fd) < 0) + goto err; + + pthread_create(&tid, NULL, poller_thread, (void *)&pmu_fd); + + sprintf(test_script, + "/usr/sbin/iptables -A INPUT -p tcp --dport %d -j DROP", + TESTPORT); + system(test_script); + + sprintf(test_script, + "/usr/bin/nc 127.0.0.1 %d < /etc/passwd > /dev/null 2>&1 ", + TESTPORT); + system(test_script); + + sprintf(test_script, + "/usr/sbin/iptables -D INPUT -p tcp --dport %d -j DROP", + TESTPORT); + system(test_script); + + rv = bpf_map_lookup_elem(map_fd, &key, &g); + if (rv != 0) { + printf("FAILED: bpf_map_lookup_elem returns %d\n", rv); + goto err; + } + + sleep(10); + + if (verify_result(&g)) { + printf("FAILED: Wrong stats Expected %d calls, got %d\n", + g.ncalls, rx_callbacks); + goto err; + } + + printf("PASSED!\n"); + error = 0; +err: + bpf_prog_detach(cg_fd, BPF_CGROUP_SOCK_OPS); + close(cg_fd); + cleanup_cgroup_environment(); + return error; +}