linux/samples/bpf/xdp_monitor_user.c
Daniel T. Lee 8ac91df6de samples: bpf: Refactor xdp_monitor with libbpf
To avoid confusion caused by the increasing fragmentation of the BPF
Loader program, this commit would like to change to the libbpf loader
instead of using the bpf_load.

Thanks to libbpf's bpf_link interface, managing the tracepoint BPF
program is much easier. bpf_program__attach_tracepoint manages the
enable of tracepoint event and attach of BPF programs to it with a
single interface bpf_link, so there is no need to manage event_fd and
prog_fd separately.

This commit refactors xdp_monitor with using this libbpf API, and the
bpf_load is removed and migrated to libbpf.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201010181734.1109-2-danieltimlee@gmail.com
2020-10-11 12:14:36 -07:00

793 lines
19 KiB
C

/* SPDX-License-Identifier: GPL-2.0
* Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc.
*/
static const char *__doc__=
"XDP monitor tool, based on tracepoints\n"
;
static const char *__doc_err_only__=
" NOTICE: Only tracking XDP redirect errors\n"
" Enable TX success stats via '--stats'\n"
" (which comes with a per packet processing overhead)\n"
;
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <locale.h>
#include <sys/resource.h>
#include <getopt.h>
#include <net/if.h>
#include <time.h>
#include <signal.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "bpf_util.h"
enum map_type {
REDIRECT_ERR_CNT,
EXCEPTION_CNT,
CPUMAP_ENQUEUE_CNT,
CPUMAP_KTHREAD_CNT,
DEVMAP_XMIT_CNT,
};
static const char *const map_type_strings[] = {
[REDIRECT_ERR_CNT] = "redirect_err_cnt",
[EXCEPTION_CNT] = "exception_cnt",
[CPUMAP_ENQUEUE_CNT] = "cpumap_enqueue_cnt",
[CPUMAP_KTHREAD_CNT] = "cpumap_kthread_cnt",
[DEVMAP_XMIT_CNT] = "devmap_xmit_cnt",
};
#define NUM_MAP 5
#define NUM_TP 8
static int tp_cnt;
static int map_cnt;
static int verbose = 1;
static bool debug = false;
struct bpf_map *map_data[NUM_MAP] = {};
struct bpf_link *tp_links[NUM_TP] = {};
struct bpf_object *obj;
static const struct option long_options[] = {
{"help", no_argument, NULL, 'h' },
{"debug", no_argument, NULL, 'D' },
{"stats", no_argument, NULL, 'S' },
{"sec", required_argument, NULL, 's' },
{0, 0, NULL, 0 }
};
static void int_exit(int sig)
{
/* Detach tracepoints */
while (tp_cnt)
bpf_link__destroy(tp_links[--tp_cnt]);
bpf_object__close(obj);
exit(0);
}
/* C standard specifies two constants, EXIT_SUCCESS(0) and EXIT_FAILURE(1) */
#define EXIT_FAIL_MEM 5
static void usage(char *argv[])
{
int i;
printf("\nDOCUMENTATION:\n%s\n", __doc__);
printf("\n");
printf(" Usage: %s (options-see-below)\n",
argv[0]);
printf(" Listing options:\n");
for (i = 0; long_options[i].name != 0; i++) {
printf(" --%-15s", long_options[i].name);
if (long_options[i].flag != NULL)
printf(" flag (internal value:%d)",
*long_options[i].flag);
else
printf("short-option: -%c",
long_options[i].val);
printf("\n");
}
printf("\n");
}
#define NANOSEC_PER_SEC 1000000000 /* 10^9 */
static __u64 gettime(void)
{
struct timespec t;
int res;
res = clock_gettime(CLOCK_MONOTONIC, &t);
if (res < 0) {
fprintf(stderr, "Error with gettimeofday! (%i)\n", res);
exit(EXIT_FAILURE);
}
return (__u64) t.tv_sec * NANOSEC_PER_SEC + t.tv_nsec;
}
enum {
REDIR_SUCCESS = 0,
REDIR_ERROR = 1,
};
#define REDIR_RES_MAX 2
static const char *redir_names[REDIR_RES_MAX] = {
[REDIR_SUCCESS] = "Success",
[REDIR_ERROR] = "Error",
};
static const char *err2str(int err)
{
if (err < REDIR_RES_MAX)
return redir_names[err];
return NULL;
}
/* enum xdp_action */
#define XDP_UNKNOWN XDP_REDIRECT + 1
#define XDP_ACTION_MAX (XDP_UNKNOWN + 1)
static const char *xdp_action_names[XDP_ACTION_MAX] = {
[XDP_ABORTED] = "XDP_ABORTED",
[XDP_DROP] = "XDP_DROP",
[XDP_PASS] = "XDP_PASS",
[XDP_TX] = "XDP_TX",
[XDP_REDIRECT] = "XDP_REDIRECT",
[XDP_UNKNOWN] = "XDP_UNKNOWN",
};
static const char *action2str(int action)
{
if (action < XDP_ACTION_MAX)
return xdp_action_names[action];
return NULL;
}
/* Common stats data record shared with _kern.c */
struct datarec {
__u64 processed;
__u64 dropped;
__u64 info;
__u64 err;
};
#define MAX_CPUS 64
/* Userspace structs for collection of stats from maps */
struct record {
__u64 timestamp;
struct datarec total;
struct datarec *cpu;
};
struct u64rec {
__u64 processed;
};
struct record_u64 {
/* record for _kern side __u64 values */
__u64 timestamp;
struct u64rec total;
struct u64rec *cpu;
};
struct stats_record {
struct record_u64 xdp_redirect[REDIR_RES_MAX];
struct record_u64 xdp_exception[XDP_ACTION_MAX];
struct record xdp_cpumap_kthread;
struct record xdp_cpumap_enqueue[MAX_CPUS];
struct record xdp_devmap_xmit;
};
static bool map_collect_record(int fd, __u32 key, struct record *rec)
{
/* For percpu maps, userspace gets a value per possible CPU */
unsigned int nr_cpus = bpf_num_possible_cpus();
struct datarec values[nr_cpus];
__u64 sum_processed = 0;
__u64 sum_dropped = 0;
__u64 sum_info = 0;
__u64 sum_err = 0;
int i;
if ((bpf_map_lookup_elem(fd, &key, values)) != 0) {
fprintf(stderr,
"ERR: bpf_map_lookup_elem failed key:0x%X\n", key);
return false;
}
/* Get time as close as possible to reading map contents */
rec->timestamp = gettime();
/* Record and sum values from each CPU */
for (i = 0; i < nr_cpus; i++) {
rec->cpu[i].processed = values[i].processed;
sum_processed += values[i].processed;
rec->cpu[i].dropped = values[i].dropped;
sum_dropped += values[i].dropped;
rec->cpu[i].info = values[i].info;
sum_info += values[i].info;
rec->cpu[i].err = values[i].err;
sum_err += values[i].err;
}
rec->total.processed = sum_processed;
rec->total.dropped = sum_dropped;
rec->total.info = sum_info;
rec->total.err = sum_err;
return true;
}
static bool map_collect_record_u64(int fd, __u32 key, struct record_u64 *rec)
{
/* For percpu maps, userspace gets a value per possible CPU */
unsigned int nr_cpus = bpf_num_possible_cpus();
struct u64rec values[nr_cpus];
__u64 sum_total = 0;
int i;
if ((bpf_map_lookup_elem(fd, &key, values)) != 0) {
fprintf(stderr,
"ERR: bpf_map_lookup_elem failed key:0x%X\n", key);
return false;
}
/* Get time as close as possible to reading map contents */
rec->timestamp = gettime();
/* Record and sum values from each CPU */
for (i = 0; i < nr_cpus; i++) {
rec->cpu[i].processed = values[i].processed;
sum_total += values[i].processed;
}
rec->total.processed = sum_total;
return true;
}
static double calc_period(struct record *r, struct record *p)
{
double period_ = 0;
__u64 period = 0;
period = r->timestamp - p->timestamp;
if (period > 0)
period_ = ((double) period / NANOSEC_PER_SEC);
return period_;
}
static double calc_period_u64(struct record_u64 *r, struct record_u64 *p)
{
double period_ = 0;
__u64 period = 0;
period = r->timestamp - p->timestamp;
if (period > 0)
period_ = ((double) period / NANOSEC_PER_SEC);
return period_;
}
static double calc_pps(struct datarec *r, struct datarec *p, double period)
{
__u64 packets = 0;
double pps = 0;
if (period > 0) {
packets = r->processed - p->processed;
pps = packets / period;
}
return pps;
}
static double calc_pps_u64(struct u64rec *r, struct u64rec *p, double period)
{
__u64 packets = 0;
double pps = 0;
if (period > 0) {
packets = r->processed - p->processed;
pps = packets / period;
}
return pps;
}
static double calc_drop(struct datarec *r, struct datarec *p, double period)
{
__u64 packets = 0;
double pps = 0;
if (period > 0) {
packets = r->dropped - p->dropped;
pps = packets / period;
}
return pps;
}
static double calc_info(struct datarec *r, struct datarec *p, double period)
{
__u64 packets = 0;
double pps = 0;
if (period > 0) {
packets = r->info - p->info;
pps = packets / period;
}
return pps;
}
static double calc_err(struct datarec *r, struct datarec *p, double period)
{
__u64 packets = 0;
double pps = 0;
if (period > 0) {
packets = r->err - p->err;
pps = packets / period;
}
return pps;
}
static void stats_print(struct stats_record *stats_rec,
struct stats_record *stats_prev,
bool err_only)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
int rec_i = 0, i, to_cpu;
double t = 0, pps = 0;
/* Header */
printf("%-15s %-7s %-12s %-12s %-9s\n",
"XDP-event", "CPU:to", "pps", "drop-pps", "extra-info");
/* tracepoint: xdp:xdp_redirect_* */
if (err_only)
rec_i = REDIR_ERROR;
for (; rec_i < REDIR_RES_MAX; rec_i++) {
struct record_u64 *rec, *prev;
char *fmt1 = "%-15s %-7d %'-12.0f %'-12.0f %s\n";
char *fmt2 = "%-15s %-7s %'-12.0f %'-12.0f %s\n";
rec = &stats_rec->xdp_redirect[rec_i];
prev = &stats_prev->xdp_redirect[rec_i];
t = calc_period_u64(rec, prev);
for (i = 0; i < nr_cpus; i++) {
struct u64rec *r = &rec->cpu[i];
struct u64rec *p = &prev->cpu[i];
pps = calc_pps_u64(r, p, t);
if (pps > 0)
printf(fmt1, "XDP_REDIRECT", i,
rec_i ? 0.0: pps, rec_i ? pps : 0.0,
err2str(rec_i));
}
pps = calc_pps_u64(&rec->total, &prev->total, t);
printf(fmt2, "XDP_REDIRECT", "total",
rec_i ? 0.0: pps, rec_i ? pps : 0.0, err2str(rec_i));
}
/* tracepoint: xdp:xdp_exception */
for (rec_i = 0; rec_i < XDP_ACTION_MAX; rec_i++) {
struct record_u64 *rec, *prev;
char *fmt1 = "%-15s %-7d %'-12.0f %'-12.0f %s\n";
char *fmt2 = "%-15s %-7s %'-12.0f %'-12.0f %s\n";
rec = &stats_rec->xdp_exception[rec_i];
prev = &stats_prev->xdp_exception[rec_i];
t = calc_period_u64(rec, prev);
for (i = 0; i < nr_cpus; i++) {
struct u64rec *r = &rec->cpu[i];
struct u64rec *p = &prev->cpu[i];
pps = calc_pps_u64(r, p, t);
if (pps > 0)
printf(fmt1, "Exception", i,
0.0, pps, action2str(rec_i));
}
pps = calc_pps_u64(&rec->total, &prev->total, t);
if (pps > 0)
printf(fmt2, "Exception", "total",
0.0, pps, action2str(rec_i));
}
/* cpumap enqueue stats */
for (to_cpu = 0; to_cpu < MAX_CPUS; to_cpu++) {
char *fmt1 = "%-15s %3d:%-3d %'-12.0f %'-12.0f %'-10.2f %s\n";
char *fmt2 = "%-15s %3s:%-3d %'-12.0f %'-12.0f %'-10.2f %s\n";
struct record *rec, *prev;
char *info_str = "";
double drop, info;
rec = &stats_rec->xdp_cpumap_enqueue[to_cpu];
prev = &stats_prev->xdp_cpumap_enqueue[to_cpu];
t = calc_period(rec, prev);
for (i = 0; i < nr_cpus; i++) {
struct datarec *r = &rec->cpu[i];
struct datarec *p = &prev->cpu[i];
pps = calc_pps(r, p, t);
drop = calc_drop(r, p, t);
info = calc_info(r, p, t);
if (info > 0) {
info_str = "bulk-average";
info = pps / info; /* calc average bulk size */
}
if (pps > 0)
printf(fmt1, "cpumap-enqueue",
i, to_cpu, pps, drop, info, info_str);
}
pps = calc_pps(&rec->total, &prev->total, t);
if (pps > 0) {
drop = calc_drop(&rec->total, &prev->total, t);
info = calc_info(&rec->total, &prev->total, t);
if (info > 0) {
info_str = "bulk-average";
info = pps / info; /* calc average bulk size */
}
printf(fmt2, "cpumap-enqueue",
"sum", to_cpu, pps, drop, info, info_str);
}
}
/* cpumap kthread stats */
{
char *fmt1 = "%-15s %-7d %'-12.0f %'-12.0f %'-10.0f %s\n";
char *fmt2 = "%-15s %-7s %'-12.0f %'-12.0f %'-10.0f %s\n";
struct record *rec, *prev;
double drop, info;
char *i_str = "";
rec = &stats_rec->xdp_cpumap_kthread;
prev = &stats_prev->xdp_cpumap_kthread;
t = calc_period(rec, prev);
for (i = 0; i < nr_cpus; i++) {
struct datarec *r = &rec->cpu[i];
struct datarec *p = &prev->cpu[i];
pps = calc_pps(r, p, t);
drop = calc_drop(r, p, t);
info = calc_info(r, p, t);
if (info > 0)
i_str = "sched";
if (pps > 0 || drop > 0)
printf(fmt1, "cpumap-kthread",
i, pps, drop, info, i_str);
}
pps = calc_pps(&rec->total, &prev->total, t);
drop = calc_drop(&rec->total, &prev->total, t);
info = calc_info(&rec->total, &prev->total, t);
if (info > 0)
i_str = "sched-sum";
printf(fmt2, "cpumap-kthread", "total", pps, drop, info, i_str);
}
/* devmap ndo_xdp_xmit stats */
{
char *fmt1 = "%-15s %-7d %'-12.0f %'-12.0f %'-10.2f %s %s\n";
char *fmt2 = "%-15s %-7s %'-12.0f %'-12.0f %'-10.2f %s %s\n";
struct record *rec, *prev;
double drop, info, err;
char *i_str = "";
char *err_str = "";
rec = &stats_rec->xdp_devmap_xmit;
prev = &stats_prev->xdp_devmap_xmit;
t = calc_period(rec, prev);
for (i = 0; i < nr_cpus; i++) {
struct datarec *r = &rec->cpu[i];
struct datarec *p = &prev->cpu[i];
pps = calc_pps(r, p, t);
drop = calc_drop(r, p, t);
info = calc_info(r, p, t);
err = calc_err(r, p, t);
if (info > 0) {
i_str = "bulk-average";
info = (pps+drop) / info; /* calc avg bulk */
}
if (err > 0)
err_str = "drv-err";
if (pps > 0 || drop > 0)
printf(fmt1, "devmap-xmit",
i, pps, drop, info, i_str, err_str);
}
pps = calc_pps(&rec->total, &prev->total, t);
drop = calc_drop(&rec->total, &prev->total, t);
info = calc_info(&rec->total, &prev->total, t);
err = calc_err(&rec->total, &prev->total, t);
if (info > 0) {
i_str = "bulk-average";
info = (pps+drop) / info; /* calc avg bulk */
}
if (err > 0)
err_str = "drv-err";
printf(fmt2, "devmap-xmit", "total", pps, drop,
info, i_str, err_str);
}
printf("\n");
}
static bool stats_collect(struct stats_record *rec)
{
int fd;
int i;
/* TODO: Detect if someone unloaded the perf event_fd's, as
* this can happen by someone running perf-record -e
*/
fd = bpf_map__fd(map_data[REDIRECT_ERR_CNT]);
for (i = 0; i < REDIR_RES_MAX; i++)
map_collect_record_u64(fd, i, &rec->xdp_redirect[i]);
fd = bpf_map__fd(map_data[EXCEPTION_CNT]);
for (i = 0; i < XDP_ACTION_MAX; i++) {
map_collect_record_u64(fd, i, &rec->xdp_exception[i]);
}
fd = bpf_map__fd(map_data[CPUMAP_ENQUEUE_CNT]);
for (i = 0; i < MAX_CPUS; i++)
map_collect_record(fd, i, &rec->xdp_cpumap_enqueue[i]);
fd = bpf_map__fd(map_data[CPUMAP_KTHREAD_CNT]);
map_collect_record(fd, 0, &rec->xdp_cpumap_kthread);
fd = bpf_map__fd(map_data[DEVMAP_XMIT_CNT]);
map_collect_record(fd, 0, &rec->xdp_devmap_xmit);
return true;
}
static void *alloc_rec_per_cpu(int record_size)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
void *array;
array = calloc(nr_cpus, record_size);
if (!array) {
fprintf(stderr, "Mem alloc error (nr_cpus:%u)\n", nr_cpus);
exit(EXIT_FAIL_MEM);
}
return array;
}
static struct stats_record *alloc_stats_record(void)
{
struct stats_record *rec;
int rec_sz;
int i;
/* Alloc main stats_record structure */
rec = calloc(1, sizeof(*rec));
if (!rec) {
fprintf(stderr, "Mem alloc error\n");
exit(EXIT_FAIL_MEM);
}
/* Alloc stats stored per CPU for each record */
rec_sz = sizeof(struct u64rec);
for (i = 0; i < REDIR_RES_MAX; i++)
rec->xdp_redirect[i].cpu = alloc_rec_per_cpu(rec_sz);
for (i = 0; i < XDP_ACTION_MAX; i++)
rec->xdp_exception[i].cpu = alloc_rec_per_cpu(rec_sz);
rec_sz = sizeof(struct datarec);
rec->xdp_cpumap_kthread.cpu = alloc_rec_per_cpu(rec_sz);
rec->xdp_devmap_xmit.cpu = alloc_rec_per_cpu(rec_sz);
for (i = 0; i < MAX_CPUS; i++)
rec->xdp_cpumap_enqueue[i].cpu = alloc_rec_per_cpu(rec_sz);
return rec;
}
static void free_stats_record(struct stats_record *r)
{
int i;
for (i = 0; i < REDIR_RES_MAX; i++)
free(r->xdp_redirect[i].cpu);
for (i = 0; i < XDP_ACTION_MAX; i++)
free(r->xdp_exception[i].cpu);
free(r->xdp_cpumap_kthread.cpu);
free(r->xdp_devmap_xmit.cpu);
for (i = 0; i < MAX_CPUS; i++)
free(r->xdp_cpumap_enqueue[i].cpu);
free(r);
}
/* Pointer swap trick */
static inline void swap(struct stats_record **a, struct stats_record **b)
{
struct stats_record *tmp;
tmp = *a;
*a = *b;
*b = tmp;
}
static void stats_poll(int interval, bool err_only)
{
struct stats_record *rec, *prev;
rec = alloc_stats_record();
prev = alloc_stats_record();
stats_collect(rec);
if (err_only)
printf("\n%s\n", __doc_err_only__);
/* Trick to pretty printf with thousands separators use %' */
setlocale(LC_NUMERIC, "en_US");
/* Header */
if (verbose)
printf("\n%s", __doc__);
/* TODO Need more advanced stats on error types */
if (verbose) {
printf(" - Stats map0: %s\n", bpf_map__name(map_data[0]));
printf(" - Stats map1: %s\n", bpf_map__name(map_data[1]));
printf("\n");
}
fflush(stdout);
while (1) {
swap(&prev, &rec);
stats_collect(rec);
stats_print(rec, prev, err_only);
fflush(stdout);
sleep(interval);
}
free_stats_record(rec);
free_stats_record(prev);
}
static void print_bpf_prog_info(void)
{
struct bpf_program *prog;
struct bpf_map *map;
int i = 0;
/* Prog info */
printf("Loaded BPF prog have %d bpf program(s)\n", tp_cnt);
bpf_object__for_each_program(prog, obj) {
printf(" - prog_fd[%d] = fd(%d)\n", i, bpf_program__fd(prog));
i++;
}
i = 0;
/* Maps info */
printf("Loaded BPF prog have %d map(s)\n", map_cnt);
bpf_object__for_each_map(map, obj) {
const char *name = bpf_map__name(map);
int fd = bpf_map__fd(map);
printf(" - map_data[%d] = fd(%d) name:%s\n", i, fd, name);
i++;
}
/* Event info */
printf("Searching for (max:%d) event file descriptor(s)\n", tp_cnt);
for (i = 0; i < tp_cnt; i++) {
int fd = bpf_link__fd(tp_links[i]);
if (fd != -1)
printf(" - event_fd[%d] = fd(%d)\n", i, fd);
}
}
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
struct bpf_program *prog;
int longindex = 0, opt;
int ret = EXIT_FAILURE;
enum map_type type;
char filename[256];
/* Default settings: */
bool errors_only = true;
int interval = 2;
/* Parse commands line args */
while ((opt = getopt_long(argc, argv, "hDSs:",
long_options, &longindex)) != -1) {
switch (opt) {
case 'D':
debug = true;
break;
case 'S':
errors_only = false;
break;
case 's':
interval = atoi(optarg);
break;
case 'h':
default:
usage(argv);
return ret;
}
}
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
if (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK)");
return ret;
}
/* Remove tracepoint program when program is interrupted or killed */
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
printf("ERROR: opening BPF object file failed\n");
obj = NULL;
goto cleanup;
}
/* load BPF program */
if (bpf_object__load(obj)) {
printf("ERROR: loading BPF object file failed\n");
goto cleanup;
}
for (type = 0; type < NUM_MAP; type++) {
map_data[type] =
bpf_object__find_map_by_name(obj, map_type_strings[type]);
if (libbpf_get_error(map_data[type])) {
printf("ERROR: finding a map in obj file failed\n");
goto cleanup;
}
map_cnt++;
}
bpf_object__for_each_program(prog, obj) {
tp_links[tp_cnt] = bpf_program__attach(prog);
if (libbpf_get_error(tp_links[tp_cnt])) {
printf("ERROR: bpf_program__attach failed\n");
tp_links[tp_cnt] = NULL;
goto cleanup;
}
tp_cnt++;
}
if (debug) {
print_bpf_prog_info();
}
/* Unload/stop tracepoint event by closing bpf_link's */
if (errors_only) {
/* The bpf_link[i] depend on the order of
* the functions was defined in _kern.c
*/
bpf_link__destroy(tp_links[2]); /* tracepoint/xdp/xdp_redirect */
tp_links[2] = NULL;
bpf_link__destroy(tp_links[3]); /* tracepoint/xdp/xdp_redirect_map */
tp_links[3] = NULL;
}
stats_poll(interval, errors_only);
ret = EXIT_SUCCESS;
cleanup:
/* Detach tracepoints */
while (tp_cnt)
bpf_link__destroy(tp_links[--tp_cnt]);
bpf_object__close(obj);
return ret;
}