summaryrefslogtreecommitdiffstats
path: root/samples/bpf
diff options
context:
space:
mode:
authorJesper Dangaard Brouer <brouer@redhat.com>2019-12-20 17:19:36 +0100
committerAlexei Starovoitov <ast@kernel.org>2019-12-20 16:13:43 -0800
commitf9e6bfdbaf0cf304d72c70a05d81acac01a04f48 (patch)
treeac70f4b3f3111f5c8001e2beec6510d527279109 /samples/bpf
parent6cd6e64e3603bd5d1677365cf935c2d8e9f496e0 (diff)
downloadlinux-f9e6bfdbaf0cf304d72c70a05d81acac01a04f48.tar.bz2
samples/bpf: Xdp_redirect_cpu fix missing tracepoint attach
When sample xdp_redirect_cpu was converted to use libbpf, the tracepoints used by this sample were not getting attached automatically like with bpf_load.c. The BPF-maps was still getting loaded, thus nobody notice that the tracepoints were not updating these maps. This fix doesn't use the new skeleton code, as this bug was introduced in v5.1 and stable might want to backport this. E.g. Red Hat QA uses this sample as part of their testing. Fixes: bbaf6029c49c ("samples/bpf: Convert XDP samples to libbpf usage") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/157685877642.26195.2798780195186786841.stgit@firesoul
Diffstat (limited to 'samples/bpf')
-rw-r--r--samples/bpf/xdp_redirect_cpu_user.c59
1 files changed, 55 insertions, 4 deletions
diff --git a/samples/bpf/xdp_redirect_cpu_user.c b/samples/bpf/xdp_redirect_cpu_user.c
index 72af628529b5..79a2fb7d16cb 100644
--- a/samples/bpf/xdp_redirect_cpu_user.c
+++ b/samples/bpf/xdp_redirect_cpu_user.c
@@ -16,6 +16,10 @@ static const char *__doc__ =
#include <getopt.h>
#include <net/if.h>
#include <time.h>
+#include <linux/limits.h>
+
+#define __must_check
+#include <linux/err.h>
#include <arpa/inet.h>
#include <linux/if_link.h>
@@ -46,6 +50,10 @@ static int cpus_count_map_fd;
static int cpus_iterator_map_fd;
static int exception_cnt_map_fd;
+#define NUM_TP 5
+struct bpf_link *tp_links[NUM_TP] = { 0 };
+static int tp_cnt = 0;
+
/* Exit return codes */
#define EXIT_OK 0
#define EXIT_FAIL 1
@@ -88,6 +96,10 @@ static void int_exit(int sig)
printf("program on interface changed, not removing\n");
}
}
+ /* Detach tracepoints */
+ while (tp_cnt)
+ bpf_link__destroy(tp_links[--tp_cnt]);
+
exit(EXIT_OK);
}
@@ -588,23 +600,61 @@ static void stats_poll(int interval, bool use_separators, char *prog_name,
free_stats_record(prev);
}
+static struct bpf_link * attach_tp(struct bpf_object *obj,
+ const char *tp_category,
+ const char* tp_name)
+{
+ struct bpf_program *prog;
+ struct bpf_link *link;
+ char sec_name[PATH_MAX];
+ int len;
+
+ len = snprintf(sec_name, PATH_MAX, "tracepoint/%s/%s",
+ tp_category, tp_name);
+ if (len < 0)
+ exit(EXIT_FAIL);
+
+ prog = bpf_object__find_program_by_title(obj, sec_name);
+ if (!prog) {
+ fprintf(stderr, "ERR: finding progsec: %s\n", sec_name);
+ exit(EXIT_FAIL_BPF);
+ }
+
+ link = bpf_program__attach_tracepoint(prog, tp_category, tp_name);
+ if (IS_ERR(link))
+ exit(EXIT_FAIL_BPF);
+
+ return link;
+}
+
+static void init_tracepoints(struct bpf_object *obj) {
+ tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_redirect_err");
+ tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_redirect_map_err");
+ tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_exception");
+ tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_cpumap_enqueue");
+ tp_links[tp_cnt++] = attach_tp(obj, "xdp", "xdp_cpumap_kthread");
+}
+
static int init_map_fds(struct bpf_object *obj)
{
- cpu_map_fd = bpf_object__find_map_fd_by_name(obj, "cpu_map");
- rx_cnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rx_cnt");
+ /* Maps updated by tracepoints */
redirect_err_cnt_map_fd =
bpf_object__find_map_fd_by_name(obj, "redirect_err_cnt");
+ exception_cnt_map_fd =
+ bpf_object__find_map_fd_by_name(obj, "exception_cnt");
cpumap_enqueue_cnt_map_fd =
bpf_object__find_map_fd_by_name(obj, "cpumap_enqueue_cnt");
cpumap_kthread_cnt_map_fd =
bpf_object__find_map_fd_by_name(obj, "cpumap_kthread_cnt");
+
+ /* Maps used by XDP */
+ rx_cnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rx_cnt");
+ cpu_map_fd = bpf_object__find_map_fd_by_name(obj, "cpu_map");
cpus_available_map_fd =
bpf_object__find_map_fd_by_name(obj, "cpus_available");
cpus_count_map_fd = bpf_object__find_map_fd_by_name(obj, "cpus_count");
cpus_iterator_map_fd =
bpf_object__find_map_fd_by_name(obj, "cpus_iterator");
- exception_cnt_map_fd =
- bpf_object__find_map_fd_by_name(obj, "exception_cnt");
if (cpu_map_fd < 0 || rx_cnt_map_fd < 0 ||
redirect_err_cnt_map_fd < 0 || cpumap_enqueue_cnt_map_fd < 0 ||
@@ -662,6 +712,7 @@ int main(int argc, char **argv)
strerror(errno));
return EXIT_FAIL;
}
+ init_tracepoints(obj);
if (init_map_fds(obj) < 0) {
fprintf(stderr, "bpf_object__find_map_fd_by_name failed\n");
return EXIT_FAIL;