The program tcp_bpf can be used to remove current global sockops program
and to load/replace sockops BPF programs. There is also an option to
print the bpf trace buffer (for debugging purposes).
USAGE:
./tcp_bpf [-r] [-l] [<pname>]
WHERE:
-r remove current loaded socketops BPF program
not needed if loading a new program
-l print BPF trace buffer. Used when loading a new program
<pname> name of BPF sockeops program to load
if <pname> does not end in ".o", then "_kern.o" is appended
example: using tcp_rto will load tcp_rto_kern.o
Signed-off-by: Lawrence Brakmo <bra...@fb.com>
---
samples/bpf/Makefile | 3 ++
samples/bpf/tcp_bpf.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 84 insertions(+)
create mode 100644 samples/bpf/tcp_bpf.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 6c7468e..b13436c 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -36,6 +36,7 @@ hostprogs-y += lwt_len_hist
hostprogs-y += xdp_tx_iptunnel
hostprogs-y += test_map_in_map
hostprogs-y += per_socket_stats_example
+hostprogs-y += tcp_bpf
# Libbpf dependencies
LIBBPF := ../../tools/lib/bpf/bpf.o
@@ -52,6 +53,7 @@ tracex3-objs := bpf_load.o $(LIBBPF) tracex3_user.o
tracex4-objs := bpf_load.o $(LIBBPF) tracex4_user.o
tracex5-objs := bpf_load.o $(LIBBPF) tracex5_user.o
tracex6-objs := bpf_load.o $(LIBBPF) tracex6_user.o
+tcp_bpf-objs := bpf_load.o $(LIBBPF) tcp_bpf.o
test_probe_write_user-objs := bpf_load.o $(LIBBPF) test_probe_write_user_user.o
trace_output-objs := bpf_load.o $(LIBBPF) trace_output_user.o
lathist-objs := bpf_load.o $(LIBBPF) lathist_user.o
@@ -130,6 +132,7 @@ HOSTLOADLIBES_tracex4 += -lelf -lrt
HOSTLOADLIBES_tracex5 += -lelf
HOSTLOADLIBES_tracex6 += -lelf
HOSTLOADLIBES_test_cgrp2_sock2 += -lelf
+HOSTLOADLIBES_tcp_bpf += -lelf
HOSTLOADLIBES_test_probe_write_user += -lelf
HOSTLOADLIBES_trace_output += -lelf -lrt
HOSTLOADLIBES_lathist += -lelf
diff --git a/samples/bpf/tcp_bpf.c b/samples/bpf/tcp_bpf.c
new file mode 100644
index 0000000..41d2124
--- /dev/null
+++ b/samples/bpf/tcp_bpf.c
@@ -0,0 +1,81 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <linux/bpf.h>
+#include "libbpf.h"
+#include "bpf_load.h"
+#include <unistd.h>
+#include <linux/unistd.h>
+
+static void usage(char *pname)
+{
+ printf("USAGE:\n %s [-r] [-l] <pname>\n", pname);
+ printf("WHERE:\n");
+ printf(" -r remove current loaded socketops BPF program\n");
+ printf(" not needed if loading a new program\n");
+ printf(" -l print out BPF log buffer\n");
+ printf(" <pname> name of BPF sockeops program to load\n");
+ printf(" if <pname> does not end in \".o\", then \"_kern.o\" "
+ "is appended\n");
+ printf(" example: using tcp1 will load tcp1_kern.o\n");
+ printf("\n");
+ exit(1);
+}
+
+int main(int argc, char **argv)
+{
+ char fn[500];
+ int k, logFlag = 0;
+ int error = -1;
+ union bpf_attr attr;
+
+ if (argc <= 1)
+ usage(argv[0]);
+ for (k = 1; k < argc; k++) {
+ if (!strcmp(argv[k], "-r")) {
+ /* A fd of zero is used as signal to remove the
+ * current SOCKET_OPS program
+ */
+ attr.bpf_fd = 0;
+ syscall(__NR_bpf, BPF_PROG_LOAD_SOCKET_OPS, &attr,
+ sizeof(attr));
+ } else if (!strcmp(argv[k], "-l")) {
+ logFlag = 1;
+ } else if (!strcmp(argv[k], "-h")) {
+ usage(argv[0]);
+ } else if (argv[k][0] == '-') {
+ printf("Error, unknown flag: %s\n", argv[k]);
+ exit(2);
+ } else if (strlen(argv[k]) > 450) {
+ printf("Error, program name too long %d\n",
+ (int) strlen(argv[k]));
+ exit(3);
+ } else {
+ if (!strcmp(argv[k]+strlen(argv[k])-2, ".o"))
+ strcpy(fn, argv[k]);
+ else
+ sprintf(fn, "%s_kern.o", argv[k]);
+ if (logFlag)
+ printf("loading bpf file:%s\n", fn);
+ if (load_bpf_file(fn)) {
+ printf("%s", bpf_log_buf);
+ return 1;
+ }
+ if (logFlag) {
+ printf("TCP BPF Loaded %s\n", fn);
+ printf("%s\n", bpf_log_buf);
+ }
+ attr.bpf_fd = prog_fd[0];
+ error = syscall(__NR_bpf, BPF_PROG_LOAD_SOCKET_OPS,
+ &attr, sizeof(attr));
+ if (error) {
+ printf("ERROR: syscall(BPF_PROG_SOCKET_OPS:
%d\n",
+ error);
+ return 2;
+ }
+ if (logFlag)
+ read_trace_pipe();
+ }
+ }
+ return 0;
+}
--
2.9.3
