bpf: Add tests and samples for LWT-BPF
Adds a series of tests to verify the functionality of attaching
BPF programs at LWT hooks.
Also adds a sample which collects a histogram of packet sizes which
pass through an LWT hook.
$ ./lwt_len_hist.sh
Starting netserver with host 'IN(6)ADDR_ANY' port '12865' and family AF_UNSPEC
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.253.2 () port 0 AF_INET : demo
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 10.00 39857.69
1 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 22 | |
64 -> 127 : 98 | |
128 -> 255 : 213 | |
256 -> 511 : 1444251 |******** |
512 -> 1023 : 660610 |*** |
1024 -> 2047 : 535241 |** |
2048 -> 4095 : 19 | |
4096 -> 8191 : 180 | |
8192 -> 16383 : 5578023 |************************************* |
16384 -> 32767 : 632099 |*** |
32768 -> 65535 : 6575 | |
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/samples/bpf/lwt_len_hist_user.c b/samples/bpf/lwt_len_hist_user.c
new file mode 100644
index 0000000..05d783f
--- /dev/null
+++ b/samples/bpf/lwt_len_hist_user.c
@@ -0,0 +1,76 @@
+#include <linux/unistd.h>
+#include <linux/bpf.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <arpa/inet.h>
+
+#include "libbpf.h"
+#include "bpf_util.h"
+
+#define MAX_INDEX 64
+#define MAX_STARS 38
+
+static void stars(char *str, long val, long max, int width)
+{
+ int i;
+
+ for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
+ str[i] = '*';
+ if (val > max)
+ str[i - 1] = '+';
+ str[i] = '\0';
+}
+
+int main(int argc, char **argv)
+{
+ unsigned int nr_cpus = bpf_num_possible_cpus();
+ const char *map_filename = "/sys/fs/bpf/tc/globals/lwt_len_hist_map";
+ uint64_t values[nr_cpus], sum, max_value = 0, data[MAX_INDEX] = {};
+ uint64_t key = 0, next_key, max_key = 0;
+ char starstr[MAX_STARS];
+ int i, map_fd;
+
+ map_fd = bpf_obj_get(map_filename);
+ if (map_fd < 0) {
+ fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
+ map_filename, strerror(errno), errno);
+ return -1;
+ }
+
+ while (bpf_get_next_key(map_fd, &key, &next_key) == 0) {
+ if (next_key >= MAX_INDEX) {
+ fprintf(stderr, "Key %lu out of bounds\n", next_key);
+ continue;
+ }
+
+ bpf_lookup_elem(map_fd, &next_key, values);
+
+ sum = 0;
+ for (i = 0; i < nr_cpus; i++)
+ sum += values[i];
+
+ data[next_key] = sum;
+ if (sum && next_key > max_key)
+ max_key = next_key;
+
+ if (sum > max_value)
+ max_value = sum;
+
+ key = next_key;
+ }
+
+ for (i = 1; i <= max_key + 1; i++) {
+ stars(starstr, data[i - 1], max_value, MAX_STARS);
+ printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
+ (1l << i) >> 1, (1l << i) - 1, data[i - 1],
+ MAX_STARS, starstr);
+ }
+
+ close(map_fd);
+
+ return 0;
+}
