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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2022 Microsoft Corporation
//
// Based on tcptracer(8) from BCC by Kinvolk GmbH and
// tcpconnect(8) by Anton Protopopov
#include <sys/resource.h>
#include <arpa/inet.h>
#include <argp.h>
#include <signal.h>
#include <limits.h>
#include <unistd.h>
#include <time.h>
#include <bpf/bpf.h>
#include "tcptracer.h"
#include "tcptracer.skel.h"
#include "btf_helpers.h"
#include "trace_helpers.h"
#include "map_helpers.h"
#define warn(...) fprintf(stderr, __VA_ARGS__)
static volatile sig_atomic_t exiting = 0;
const char *argp_program_version = "tcptracer 0.1";
const char *argp_program_bug_address =
"https://github.com/iovisor/bcc/tree/master/libbpf-tools";
static const char argp_program_doc[] =
"\ntcptracer: Trace TCP connections\n"
"\n"
"EXAMPLES:\n"
" tcptracer # trace all TCP connections\n"
" tcptracer -t # include timestamps\n"
" tcptracer -p 181 # only trace PID 181\n"
" tcptracer -U # include UID\n"
" tcptracer -u 1000 # only trace UID 1000\n"
" tcptracer --C mappath # only trace cgroups in the map\n"
" tcptracer --M mappath # only trace mount namespaces in the map\n"
;
static int get_int(const char *arg, int *ret, int min, int max)
{
char *end;
long val;
errno = 0;
val = strtol(arg, &end, 10);
if (errno) {
warn("strtol: %s: %s\n", arg, strerror(errno));
return -1;
} else if (end == arg || val < min || val > max) {
return -1;
}
if (ret)
*ret = val;
return 0;
}
static int get_uint(const char *arg, unsigned int *ret,
unsigned int min, unsigned int max)
{
char *end;
long val;
errno = 0;
val = strtoul(arg, &end, 10);
if (errno) {
warn("strtoul: %s: %s\n", arg, strerror(errno));
return -1;
} else if (end == arg || val < min || val > max) {
return -1;
}
if (ret)
*ret = val;
return 0;
}
static const struct argp_option opts[] = {
{ "verbose", 'v', NULL, 0, "Verbose debug output" },
{ "timestamp", 't', NULL, 0, "Include timestamp on output" },
{ "print-uid", 'U', NULL, 0, "Include UID on output" },
{ "pid", 'p', "PID", 0, "Process PID to trace" },
{ "uid", 'u', "UID", 0, "Process UID to trace" },
{ "cgroupmap", 'C', "PATH", 0, "trace cgroups in this map" },
{ "mntnsmap", 'M', "PATH", 0, "trace mount namespaces in this map" },
{ NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help" },
{},
};
static struct env {
bool verbose;
bool count;
bool print_timestamp;
bool print_uid;
pid_t pid;
uid_t uid;
} env = {
.uid = (uid_t) -1,
};
static error_t parse_arg(int key, char *arg, struct argp_state *state)
{
int err;
switch (key) {
case 'h':
argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
break;
case 'v':
env.verbose = true;
break;
case 'c':
env.count = true;
break;
case 't':
env.print_timestamp = true;
break;
case 'U':
env.print_uid = true;
break;
case 'p':
err = get_int(arg, &env.pid, 1, INT_MAX);
if (err) {
warn("invalid PID: %s\n", arg);
argp_usage(state);
}
break;
case 'u':
err = get_uint(arg, &env.uid, 0, (uid_t) -2);
if (err) {
warn("invalid UID: %s\n", arg);
argp_usage(state);
}
break;
case 'C':
warn("not implemented: --cgroupmap");
break;
case 'M':
warn("not implemented: --mntnsmap");
break;
default:
return ARGP_ERR_UNKNOWN;
}
return 0;
}
static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
{
if (level == LIBBPF_DEBUG && !env.verbose)
return 0;
return vfprintf(stderr, format, args);
}
static void sig_int(int signo)
{
exiting = 1;
}
static void print_events_header()
{
if (env.print_timestamp)
printf("%-9s", "TIME(s)");
if (env.print_uid)
printf("%-6s", "UID");
printf("%s %-6s %-12s %-2s %-16s %-16s %-4s %-4s\n",
"T", "PID", "COMM", "IP", "SADDR", "DADDR", "SPORT", "DPORT");
}
static void handle_event(void *ctx, int cpu, void *data, __u32 data_sz)
{
const struct event *event = data;
char src[INET6_ADDRSTRLEN];
char dst[INET6_ADDRSTRLEN];
union {
struct in_addr x4;
struct in6_addr x6;
} s, d;
static __u64 start_ts;
if (event->af == AF_INET) {
s.x4.s_addr = event->saddr_v4;
d.x4.s_addr = event->daddr_v4;
} else if (event->af == AF_INET6) {
memcpy(&s.x6.s6_addr, &event->saddr_v6, sizeof(s.x6.s6_addr));
memcpy(&d.x6.s6_addr, &event->daddr_v6, sizeof(d.x6.s6_addr));
} else {
warn("broken event: event->af=%d", event->af);
return;
}
if (env.print_timestamp) {
if (start_ts == 0)
start_ts = event->ts_us;
printf("%-9.3f", (event->ts_us - start_ts) / 1000000.0);
}
if (env.print_uid)
printf("%-6d", event->uid);
char type = '-';
switch (event->type) {
case TCP_EVENT_TYPE_CONNECT:
type = 'C';
break;
case TCP_EVENT_TYPE_ACCEPT:
type = 'A';
break;
case TCP_EVENT_TYPE_CLOSE:
type = 'X';
break;
}
printf("%c %-6d %-12.12s %-2d %-16s %-16s %-4d %-4d\n",
type, event->pid, event->task,
event->af == AF_INET ? 4 : 6,
inet_ntop(event->af, &s, src, sizeof(src)),
inet_ntop(event->af, &d, dst, sizeof(dst)),
ntohs(event->sport), ntohs(event->dport));
}
static void handle_lost_events(void *ctx, int cpu, __u64 lost_cnt)
{
warn("Lost %llu events on CPU #%d!\n", lost_cnt, cpu);
}
static void print_events(int perf_map_fd)
{
struct perf_buffer *pb;
int err;
pb = perf_buffer__new(perf_map_fd, 128,
handle_event, handle_lost_events, NULL, NULL);
if (!pb) {
err = -errno;
warn("failed to open perf buffer: %d\n", err);
goto cleanup;
}
print_events_header();
while (!exiting) {
err = perf_buffer__poll(pb, 100);
if (err < 0 && err != -EINTR) {
warn("error polling perf buffer: %s\n", strerror(-err));
goto cleanup;
}
/* reset err to return 0 if exiting */
err = 0;
}
cleanup:
perf_buffer__free(pb);
}
int main(int argc, char **argv)
{
LIBBPF_OPTS(bpf_object_open_opts, open_opts);
static const struct argp argp = {
.options = opts,
.parser = parse_arg,
.doc = argp_program_doc,
.args_doc = NULL,
};
struct tcptracer_bpf *obj;
int err;
err = argp_parse(&argp, argc, argv, 0, NULL, NULL);
if (err)
return err;
libbpf_set_print(libbpf_print_fn);
err = ensure_core_btf(&open_opts);
if (err) {
fprintf(stderr, "failed to fetch necessary BTF for CO-RE: %s\n", strerror(-err));
return 1;
}
obj = tcptracer_bpf__open_opts(&open_opts);
if (!obj) {
warn("failed to open BPF object\n");
return 1;
}
if (env.pid)
obj->rodata->filter_pid = env.pid;
if (env.uid != (uid_t) -1)
obj->rodata->filter_uid = env.uid;
err = tcptracer_bpf__load(obj);
if (err) {
warn("failed to load BPF object: %d\n", err);
goto cleanup;
}
err = tcptracer_bpf__attach(obj);
if (err) {
warn("failed to attach BPF programs: %s\n", strerror(-err));
goto cleanup;
}
if (signal(SIGINT, sig_int) == SIG_ERR) {
warn("can't set signal handler: %s\n", strerror(errno));
err = 1;
goto cleanup;
}
print_events(bpf_map__fd(obj->maps.events));
cleanup:
tcptracer_bpf__destroy(obj);
cleanup_core_btf(&open_opts);
return err != 0;
}