tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com>
3 */
4#include <linux/bpf.h>
5#include <linux/if_link.h>
6#include <assert.h>
7#include <errno.h>
8#include <signal.h>
9#include <stdio.h>
10#include <stdlib.h>
11#include <stdbool.h>
12#include <string.h>
13#include <net/if.h>
14#include <unistd.h>
15#include <libgen.h>
16#include <sys/resource.h>
17
18#include "bpf_util.h"
19#include <bpf/bpf.h>
20#include <bpf/libbpf.h>
21
22static int ifindex_in;
23static int ifindex_out;
24static bool ifindex_out_xdp_dummy_attached = true;
25static __u32 prog_id;
26static __u32 dummy_prog_id;
27
28static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
29static int rxcnt_map_fd;
30
31static void int_exit(int sig)
32{
33 __u32 curr_prog_id = 0;
34
35 if (bpf_get_link_xdp_id(ifindex_in, &curr_prog_id, xdp_flags)) {
36 printf("bpf_get_link_xdp_id failed\n");
37 exit(1);
38 }
39 if (prog_id == curr_prog_id)
40 bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
41 else if (!curr_prog_id)
42 printf("couldn't find a prog id on iface IN\n");
43 else
44 printf("program on iface IN changed, not removing\n");
45
46 if (ifindex_out_xdp_dummy_attached) {
47 curr_prog_id = 0;
48 if (bpf_get_link_xdp_id(ifindex_out, &curr_prog_id,
49 xdp_flags)) {
50 printf("bpf_get_link_xdp_id failed\n");
51 exit(1);
52 }
53 if (dummy_prog_id == curr_prog_id)
54 bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
55 else if (!curr_prog_id)
56 printf("couldn't find a prog id on iface OUT\n");
57 else
58 printf("program on iface OUT changed, not removing\n");
59 }
60 exit(0);
61}
62
63static void poll_stats(int interval, int ifindex)
64{
65 unsigned int nr_cpus = bpf_num_possible_cpus();
66 __u64 values[nr_cpus], prev[nr_cpus];
67
68 memset(prev, 0, sizeof(prev));
69
70 while (1) {
71 __u64 sum = 0;
72 __u32 key = 0;
73 int i;
74
75 sleep(interval);
76 assert(bpf_map_lookup_elem(rxcnt_map_fd, &key, values) == 0);
77 for (i = 0; i < nr_cpus; i++)
78 sum += (values[i] - prev[i]);
79 if (sum)
80 printf("ifindex %i: %10llu pkt/s\n",
81 ifindex, sum / interval);
82 memcpy(prev, values, sizeof(values));
83 }
84}
85
86static void usage(const char *prog)
87{
88 fprintf(stderr,
89 "usage: %s [OPTS] <IFNAME|IFINDEX>_IN <IFNAME|IFINDEX>_OUT\n\n"
90 "OPTS:\n"
91 " -S use skb-mode\n"
92 " -N enforce native mode\n"
93 " -F force loading prog\n",
94 prog);
95}
96
97
98int main(int argc, char **argv)
99{
100 struct bpf_prog_load_attr prog_load_attr = {
101 .prog_type = BPF_PROG_TYPE_XDP,
102 };
103 struct bpf_program *prog, *dummy_prog;
104 int prog_fd, tx_port_map_fd, opt;
105 struct bpf_prog_info info = {};
106 __u32 info_len = sizeof(info);
107 const char *optstr = "FSN";
108 struct bpf_object *obj;
109 char filename[256];
110 int dummy_prog_fd;
111 int ret, key = 0;
112
113 while ((opt = getopt(argc, argv, optstr)) != -1) {
114 switch (opt) {
115 case 'S':
116 xdp_flags |= XDP_FLAGS_SKB_MODE;
117 break;
118 case 'N':
119 /* default, set below */
120 break;
121 case 'F':
122 xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
123 break;
124 default:
125 usage(basename(argv[0]));
126 return 1;
127 }
128 }
129
130 if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
131 xdp_flags |= XDP_FLAGS_DRV_MODE;
132
133 if (optind + 2 != argc) {
134 printf("usage: %s <IFNAME|IFINDEX>_IN <IFNAME|IFINDEX>_OUT\n", argv[0]);
135 return 1;
136 }
137
138 ifindex_in = if_nametoindex(argv[optind]);
139 if (!ifindex_in)
140 ifindex_in = strtoul(argv[optind], NULL, 0);
141
142 ifindex_out = if_nametoindex(argv[optind + 1]);
143 if (!ifindex_out)
144 ifindex_out = strtoul(argv[optind + 1], NULL, 0);
145
146 printf("input: %d output: %d\n", ifindex_in, ifindex_out);
147
148 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
149 prog_load_attr.file = filename;
150
151 if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
152 return 1;
153
154 prog = bpf_program__next(NULL, obj);
155 dummy_prog = bpf_program__next(prog, obj);
156 if (!prog || !dummy_prog) {
157 printf("finding a prog in obj file failed\n");
158 return 1;
159 }
160 /* bpf_prog_load_xattr gives us the pointer to first prog's fd,
161 * so we're missing only the fd for dummy prog
162 */
163 dummy_prog_fd = bpf_program__fd(dummy_prog);
164 if (prog_fd < 0 || dummy_prog_fd < 0) {
165 printf("bpf_prog_load_xattr: %s\n", strerror(errno));
166 return 1;
167 }
168
169 tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port");
170 rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt");
171 if (tx_port_map_fd < 0 || rxcnt_map_fd < 0) {
172 printf("bpf_object__find_map_fd_by_name failed\n");
173 return 1;
174 }
175
176 if (bpf_set_link_xdp_fd(ifindex_in, prog_fd, xdp_flags) < 0) {
177 printf("ERROR: link set xdp fd failed on %d\n", ifindex_in);
178 return 1;
179 }
180
181 ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
182 if (ret) {
183 printf("can't get prog info - %s\n", strerror(errno));
184 return ret;
185 }
186 prog_id = info.id;
187
188 /* Loading dummy XDP prog on out-device */
189 if (bpf_set_link_xdp_fd(ifindex_out, dummy_prog_fd,
190 (xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
191 printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
192 ifindex_out_xdp_dummy_attached = false;
193 }
194
195 memset(&info, 0, sizeof(info));
196 ret = bpf_obj_get_info_by_fd(dummy_prog_fd, &info, &info_len);
197 if (ret) {
198 printf("can't get prog info - %s\n", strerror(errno));
199 return ret;
200 }
201 dummy_prog_id = info.id;
202
203 signal(SIGINT, int_exit);
204 signal(SIGTERM, int_exit);
205
206 /* bpf redirect port */
207 ret = bpf_map_update_elem(tx_port_map_fd, &key, &ifindex_out, 0);
208 if (ret) {
209 perror("bpf_update_elem");
210 goto out;
211 }
212
213 poll_stats(2, ifindex_out);
214
215out:
216 return ret;
217}