@@ -52,6 +52,7 @@ hostprogs-y += xdp_adjust_tail
hostprogs-y += xdpsock
hostprogs-y += xdp_fwd
hostprogs-y += task_fd_query
+hostprogs-y += xdp_sample_pkts
# Libbpf dependencies
LIBBPF = $(TOOLS_PATH)/lib/bpf/libbpf.a
@@ -107,6 +108,7 @@ xdp_adjust_tail-objs := xdp_adjust_tail_user.o
xdpsock-objs := bpf_load.o xdpsock_user.o
xdp_fwd-objs := bpf_load.o xdp_fwd_user.o
task_fd_query-objs := bpf_load.o task_fd_query_user.o $(TRACE_HELPERS)
+xdp_sample_pkts-objs := xdp_sample_pkts_user.o $(TRACE_HELPERS)
# Tell kbuild to always build the programs
always := $(hostprogs-y)
@@ -163,6 +165,7 @@ always += xdp_adjust_tail_kern.o
always += xdpsock_kern.o
always += xdp_fwd_kern.o
always += task_fd_query_kern.o
+always += xdp_sample_pkts_kern.o
HOSTCFLAGS += -I$(objtree)/usr/include
HOSTCFLAGS += -I$(srctree)/tools/lib/
@@ -179,6 +182,7 @@ HOSTCFLAGS_spintest_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_trace_event_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_sampleip_user.o += -I$(srctree)/tools/lib/bpf/
HOSTCFLAGS_task_fd_query_user.o += -I$(srctree)/tools/lib/bpf/
+HOSTCFLAGS_xdp_sample_pkts_user.o += -I$(srctree)/tools/lib/bpf/
HOST_LOADLIBES += $(LIBBPF) -lelf
HOSTLOADLIBES_tracex4 += -lrt
new file mode 100644
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ptrace.h>
+#include <linux/version.h>
+#include <uapi/linux/bpf.h>
+#include "bpf_helpers.h"
+
+#define SAMPLE_SIZE 64ul
+#define MAX_CPUS 128
+
+#define bpf_printk(fmt, ...) \
+({ \
+ char ____fmt[] = fmt; \
+ bpf_trace_printk(____fmt, sizeof(____fmt), \
+ ##__VA_ARGS__); \
+})
+
+struct bpf_map_def SEC("maps") my_map = {
+ .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
+ .key_size = sizeof(int),
+ .value_size = sizeof(u32),
+ .max_entries = MAX_CPUS,
+};
+
+SEC("xdp_sample")
+int xdp_sample_prog(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+
+ /* Metadata will be in the perf event before the packet data. */
+ struct S {
+ u16 cookie;
+ u16 pkt_len;
+ } __packed metadata;
+
+ if (data < data_end) {
+ /* The XDP perf_event_output handler will use the upper 32 bits
+ * of the flags argument as a number of bytes to include of the
+ * packet payload in the event data. If the size is too big, the
+ * call to bpf_perf_event_output will fail and return -EFAULT.
+ *
+ * See bpf_xdp_event_output in net/core/filter.c.
+ *
+ * The BPF_F_CURRENT_CPU flag means that the event output fd
+ * will be indexed by the CPU number in the event map.
+ */
+ u64 flags = BPF_F_CURRENT_CPU;
+ u16 sample_size;
+ int ret;
+
+ metadata.cookie = 0xdead;
+ metadata.pkt_len = (u16)(data_end - data);
+ sample_size = min(metadata.pkt_len, SAMPLE_SIZE);
+ flags |= (u64)sample_size << 32;
+
+ ret = bpf_perf_event_output(ctx, &my_map, flags,
+ &metadata, sizeof(metadata));
+ if (ret)
+ bpf_printk("perf_event_output failed: %d\n", ret);
+ }
+
+ return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;
new file mode 100644
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <linux/perf_event.h>
+#include <linux/bpf.h>
+#include <net/if.h>
+#include <errno.h>
+#include <assert.h>
+#include <sys/sysinfo.h>
+#include <sys/ioctl.h>
+#include <signal.h>
+#include <libbpf.h>
+#include <bpf/bpf.h>
+
+#include "perf-sys.h"
+#include "trace_helpers.h"
+
+#define MAX_CPUS 128
+static int pmu_fds[MAX_CPUS], if_idx;
+static struct perf_event_mmap_page *headers[MAX_CPUS];
+static char *if_name;
+
+static int do_attach(int idx, int fd, const char *name)
+{
+ int err;
+
+ err = bpf_set_link_xdp_fd(idx, fd, 0);
+ if (err < 0)
+ printf("ERROR: failed to attach program to %s\n", name);
+
+ return err;
+}
+
+static int do_detach(int idx, const char *name)
+{
+ int err;
+
+ err = bpf_set_link_xdp_fd(idx, -1, 0);
+ if (err < 0)
+ printf("ERROR: failed to detach program from %s\n", name);
+
+ return err;
+}
+
+#define SAMPLE_SIZE 64
+
+static int print_bpf_output(void *data, int size)
+{
+ struct {
+ __u16 cookie;
+ __u16 pkt_len;
+ __u8 pkt_data[SAMPLE_SIZE];
+ } __packed *e = data;
+ int i;
+
+ if (e->cookie != 0xdead) {
+ printf("BUG cookie %x sized %d\n",
+ e->cookie, size);
+ return LIBBPF_PERF_EVENT_ERROR;
+ }
+
+ printf("Pkt len: %-5d bytes. Ethernet hdr: ", e->pkt_len);
+ for (i = 0; i < 14 && i < e->pkt_len; i++)
+ printf("%02x ", e->pkt_data[i]);
+ printf("\n");
+
+ return LIBBPF_PERF_EVENT_CONT;
+}
+
+static void test_bpf_perf_event(int map_fd, int num)
+{
+ struct perf_event_attr attr = {
+ .sample_type = PERF_SAMPLE_RAW,
+ .type = PERF_TYPE_SOFTWARE,
+ .config = PERF_COUNT_SW_BPF_OUTPUT,
+ .wakeup_events = 1, /* get an fd notification for every event */
+ };
+ int i;
+
+ for (i = 0; i < num; i++) {
+ int key = i;
+
+ pmu_fds[i] = sys_perf_event_open(&attr, -1/*pid*/, i/*cpu*/,
+ -1/*group_fd*/, 0);
+
+ assert(pmu_fds[i] >= 0);
+ assert(bpf_map_update_elem(map_fd, &key,
+ &pmu_fds[i], BPF_ANY) == 0);
+ ioctl(pmu_fds[i], PERF_EVENT_IOC_ENABLE, 0);
+ }
+}
+
+static void sig_handler(int signo)
+{
+ do_detach(if_idx, if_name);
+ exit(0);
+}
+
+int main(int argc, char **argv)
+{
+ struct bpf_prog_load_attr prog_load_attr = {
+ .prog_type = BPF_PROG_TYPE_XDP,
+ };
+ struct bpf_object *obj;
+ struct bpf_map *map;
+ int prog_fd, map_fd;
+ char filename[256];
+ int ret, err, i;
+ int numcpus;
+
+ if (argc < 2) {
+ printf("Usage: %s <ifname>\n", argv[0]);
+ return 1;
+ }
+
+ numcpus = get_nprocs();
+ if (numcpus > MAX_CPUS)
+ numcpus = MAX_CPUS;
+
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+ prog_load_attr.file = filename;
+
+ if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
+ return 1;
+
+ if (!prog_fd) {
+ printf("load_bpf_file: %s\n", strerror(errno));
+ return 1;
+ }
+
+ map = bpf_map__next(NULL, obj);
+ if (!map) {
+ printf("finding a map in obj file failed\n");
+ return 1;
+ }
+ map_fd = bpf_map__fd(map);
+
+ if_idx = if_nametoindex(argv[1]);
+ if (!if_idx)
+ if_idx = strtoul(argv[1], NULL, 0);
+
+ if (!if_idx) {
+ fprintf(stderr, "Invalid ifname\n");
+ return 1;
+ }
+ if_name = argv[1];
+ err = do_attach(if_idx, prog_fd, argv[1]);
+ if (err)
+ return err;
+
+ if (signal(SIGINT, sig_handler) ||
+ signal(SIGHUP, sig_handler) ||
+ signal(SIGTERM, sig_handler)) {
+ perror("signal");
+ return 1;
+ }
+
+ test_bpf_perf_event(map_fd, numcpus);
+
+ for (i = 0; i < numcpus; i++)
+ if (perf_event_mmap_header(pmu_fds[i], &headers[i]) < 0)
+ return 1;
+
+ ret = perf_event_poller_multi(pmu_fds, headers, numcpus,
+ print_bpf_output);
+ kill(0, SIGINT);
+ return ret;
+}