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@xxxxxxxxx>
---
samples/bpf/Makefile | 2 +-
samples/bpf/xdp_monitor_user.c | 144 ++++++++++++++++++++++++---------
2 files changed, 108 insertions(+), 38 deletions(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 4f1ed0e3cf9f..0cee2aa8970f 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -99,7 +99,7 @@ per_socket_stats_example-objs := cookie_uid_helper_example.o
xdp_redirect-objs := xdp_redirect_user.o
xdp_redirect_map-objs := xdp_redirect_map_user.o
xdp_redirect_cpu-objs := bpf_load.o xdp_redirect_cpu_user.o
-xdp_monitor-objs := bpf_load.o xdp_monitor_user.o
+xdp_monitor-objs := xdp_monitor_user.o
xdp_rxq_info-objs := xdp_rxq_info_user.o
syscall_tp-objs := syscall_tp_user.o
cpustat-objs := cpustat_user.o
diff --git a/samples/bpf/xdp_monitor_user.c b/samples/bpf/xdp_monitor_user.c
index ef53b93db573..c627c53d6ada 100644
--- a/samples/bpf/xdp_monitor_user.c
+++ b/samples/bpf/xdp_monitor_user.c
@@ -26,12 +26,36 @@ static const char *__doc_err_only__=
#include <net/if.h>
#include <time.h>
+#include <signal.h>
#include <bpf/bpf.h>
-#include "bpf_load.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] = { 0 };
+struct bpf_link *tp_links[NUM_TP] = { 0 };
static const struct option long_options[] = {
{"help", no_argument, NULL, 'h' },
@@ -41,6 +65,15 @@ static const struct option long_options[] = {
{0, 0, NULL, 0 }
};
+static void int_exit(int sig)
+{
+ /* Detach tracepoints */
+ while (tp_cnt)
+ bpf_link__destroy(tp_links[--tp_cnt]);
+
+ exit(0);
+}
+
/* C standard specifies two constants, EXIT_SUCCESS(0) and EXIT_FAILURE(1) */
#define EXIT_FAIL_MEM 5
@@ -483,23 +516,23 @@ static bool stats_collect(struct stats_record *rec)
* this can happen by someone running perf-record -e
*/
- fd = map_data[0].fd; /* map0: redirect_err_cnt */
+ 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 = map_data[1].fd; /* map1: exception_cnt */
+ 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 = map_data[2].fd; /* map2: cpumap_enqueue_cnt */
+ 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 = map_data[3].fd; /* map3: cpumap_kthread_cnt */
+ fd = bpf_map__fd(map_data[CPUMAP_KTHREAD_CNT]);
map_collect_record(fd, 0, &rec->xdp_cpumap_kthread);
- fd = map_data[4].fd; /* map4: devmap_xmit_cnt */
+ fd = bpf_map__fd(map_data[DEVMAP_XMIT_CNT]);
map_collect_record(fd, 0, &rec->xdp_devmap_xmit);
return true;
@@ -598,8 +631,8 @@ static void stats_poll(int interval, bool err_only)
/* TODO Need more advanced stats on error types */
if (verbose) {
- printf(" - Stats map0: %s\n", map_data[0].name);
- printf(" - Stats map1: %s\n", map_data[1].name);
+ 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);
@@ -616,46 +649,52 @@ static void stats_poll(int interval, bool err_only)
free_stats_record(prev);
}
-static void print_bpf_prog_info(void)
+static void print_bpf_prog_info(struct bpf_object *obj)
{
- int i;
+ struct bpf_program *prog;
+ struct bpf_map *map;
+ int i = 0;
/* Prog info */
- printf("Loaded BPF prog have %d bpf program(s)\n", prog_cnt);
- for (i = 0; i < prog_cnt; i++) {
- printf(" - prog_fd[%d] = fd(%d)\n", i, prog_fd[i]);
+ 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 = 0;
/* Maps info */
- printf("Loaded BPF prog have %d map(s)\n", map_data_count);
- for (i = 0; i < map_data_count; i++) {
- char *name = map_data[i].name;
- int fd = map_data[i].fd;
+ 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);
+ printf(" - map_data[%d] = fd(%d) name:%s\n", i++, fd, name);
}
/* Event info */
- printf("Searching for (max:%d) event file descriptor(s)\n", prog_cnt);
- for (i = 0; i < prog_cnt; i++) {
- if (event_fd[i] != -1)
- printf(" - event_fd[%d] = fd(%d)\n", i, event_fd[i]);
+ 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;
+ struct bpf_object *obj;
int longindex = 0, opt;
int ret = EXIT_SUCCESS;
- char bpf_obj_file[256];
+ enum map_type type;
+ char filename[256];
/* Default settings: */
bool errors_only = true;
int interval = 2;
- snprintf(bpf_obj_file, sizeof(bpf_obj_file), "%s_kern.o", argv[0]);
-
/* Parse commands line args */
while ((opt = getopt_long(argc, argv, "hDSs:",
long_options, &longindex)) != -1) {
@@ -676,33 +715,64 @@ int main(int argc, char **argv)
}
}
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
if (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK)");
return EXIT_FAILURE;
}
- if (load_bpf_file(bpf_obj_file)) {
- printf("ERROR - bpf_log_buf: %s", bpf_log_buf);
+ /* 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;
return EXIT_FAILURE;
}
- if (!prog_fd[0]) {
- printf("ERROR - load_bpf_file: %s\n", strerror(errno));
+
+ /* load BPF program */
+ if (bpf_object__load(obj)) {
+ printf("ERROR: loading BPF object file failed\n");
return EXIT_FAILURE;
}
+ 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");
+ return EXIT_FAILURE;
+ }
+ 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;
+ return EXIT_FAILURE;
+ }
+ tp_cnt++;
+ }
+
if (debug) {
- print_bpf_prog_info();
+ print_bpf_prog_info(obj);
}
- /* Unload/stop tracepoint event by closing fd's */
+ /* Unload/stop tracepoint event by closing bpf_link's */
if (errors_only) {
- /* The prog_fd[i] and event_fd[i] depend on the
- * order the functions was defined in _kern.c
+ /* The bpf_link[i] depend on the order of
+ * the functions was defined in _kern.c
*/
- close(event_fd[2]); /* tracepoint/xdp/xdp_redirect */
- close(prog_fd[2]); /* func: trace_xdp_redirect */
- close(event_fd[3]); /* tracepoint/xdp/xdp_redirect_map */
- close(prog_fd[3]); /* func: trace_xdp_redirect_map */
+ 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);
--
2.25.1
