linux_dsm_epyc7002/tools/testing/selftests/bpf/test_tcpnotify_user.c
Sowmini Varadhan 435f90a338 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 <sowmini.varadhan@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-11-09 09:40:17 +01:00

187 lines
3.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <pthread.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <asm/types.h>
#include <sys/syscall.h>
#include <errno.h>
#include <string.h>
#include <linux/bpf.h>
#include <sys/socket.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include <sys/ioctl.h>
#include <linux/rtnetlink.h>
#include <signal.h>
#include <linux/perf_event.h>
#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;
}