2 * Test functionality of BPF filters for SO_REUSEPORT. The tests below will use
3 * a BPF program (both classic and extended) to read the first word from an
4 * incoming packet (expected to be in network byte-order), calculate a modulus
5 * of that number, and then dispatch the packet to the Nth socket using the
6 * result. These tests are run for each supported address family and protocol.
7 * Additionally, a few edge cases in the implementation are tested.
12 #include <linux/bpf.h>
13 #include <linux/filter.h>
14 #include <linux/unistd.h>
15 #include <netinet/in.h>
19 #include <sys/epoll.h>
20 #include <sys/types.h>
21 #include <sys/socket.h>
25 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
34 uint16_t send_port_min;
37 static size_t sockaddr_size(void)
39 return sizeof(struct sockaddr_storage);
42 static struct sockaddr *new_any_sockaddr(int family, uint16_t port)
44 struct sockaddr_storage *addr;
45 struct sockaddr_in *addr4;
46 struct sockaddr_in6 *addr6;
48 addr = malloc(sizeof(struct sockaddr_storage));
49 memset(addr, 0, sizeof(struct sockaddr_storage));
53 addr4 = (struct sockaddr_in *)addr;
54 addr4->sin_family = AF_INET;
55 addr4->sin_addr.s_addr = htonl(INADDR_ANY);
56 addr4->sin_port = htons(port);
59 addr6 = (struct sockaddr_in6 *)addr;
60 addr6->sin6_family = AF_INET6;
61 addr6->sin6_addr = in6addr_any;
62 addr6->sin6_port = htons(port);
65 error(1, 0, "Unsupported family %d", family);
67 return (struct sockaddr *)addr;
70 static struct sockaddr *new_loopback_sockaddr(int family, uint16_t port)
72 struct sockaddr *addr = new_any_sockaddr(family, port);
73 struct sockaddr_in *addr4;
74 struct sockaddr_in6 *addr6;
78 addr4 = (struct sockaddr_in *)addr;
79 addr4->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
82 addr6 = (struct sockaddr_in6 *)addr;
83 addr6->sin6_addr = in6addr_loopback;
86 error(1, 0, "Unsupported family %d", family);
91 static void attach_ebpf(int fd, uint16_t mod)
93 static char bpf_log_buf[65536];
94 static const char bpf_license[] = "GPL";
97 const struct bpf_insn prog[] = {
98 /* BPF_MOV64_REG(BPF_REG_6, BPF_REG_1) */
99 { BPF_ALU64 | BPF_MOV | BPF_X, BPF_REG_6, BPF_REG_1, 0, 0 },
100 /* BPF_LD_ABS(BPF_W, 0) R0 = (uint32_t)skb[0] */
101 { BPF_LD | BPF_ABS | BPF_W, 0, 0, 0, 0 },
102 /* BPF_ALU64_IMM(BPF_MOD, BPF_REG_0, mod) */
103 { BPF_ALU64 | BPF_MOD | BPF_K, BPF_REG_0, 0, 0, mod },
104 /* BPF_EXIT_INSN() */
105 { BPF_JMP | BPF_EXIT, 0, 0, 0, 0 }
109 memset(&attr, 0, sizeof(attr));
110 attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
111 attr.insn_cnt = ARRAY_SIZE(prog);
112 attr.insns = (uint64_t)prog;
113 attr.license = (uint64_t)bpf_license;
114 attr.log_buf = (uint64_t)bpf_log_buf;
115 attr.log_size = sizeof(bpf_log_buf);
117 attr.kern_version = 0;
119 bpf_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
121 error(1, errno, "ebpf error. log:\n%s\n", bpf_log_buf);
123 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF, &bpf_fd,
125 error(1, errno, "failed to set SO_ATTACH_REUSEPORT_EBPF");
128 static void attach_cbpf(int fd, uint16_t mod)
130 struct sock_filter code[] = {
131 /* A = (uint32_t)skb[0] */
132 { BPF_LD | BPF_W | BPF_ABS, 0, 0, 0 },
134 { BPF_ALU | BPF_MOD, 0, 0, mod },
136 { BPF_RET | BPF_A, 0, 0, 0 },
138 struct sock_fprog p = {
139 .len = ARRAY_SIZE(code),
143 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF, &p, sizeof(p)))
144 error(1, errno, "failed to set SO_ATTACH_REUSEPORT_CBPF");
147 static void build_recv_group(const struct test_params p, int fd[], uint16_t mod,
148 void (*attach_bpf)(int, uint16_t))
150 struct sockaddr * const addr =
151 new_any_sockaddr(p.recv_family, p.recv_port);
154 for (i = 0; i < p.recv_socks; ++i) {
155 fd[i] = socket(p.recv_family, p.protocol, 0);
157 error(1, errno, "failed to create recv %d", i);
160 if (setsockopt(fd[i], SOL_SOCKET, SO_REUSEPORT, &opt,
162 error(1, errno, "failed to set SO_REUSEPORT on %d", i);
165 attach_bpf(fd[i], mod);
167 if (bind(fd[i], addr, sockaddr_size()))
168 error(1, errno, "failed to bind recv socket %d", i);
170 if (p.protocol == SOCK_STREAM)
171 if (listen(fd[i], p.recv_socks * 10))
172 error(1, errno, "failed to listen on socket");
177 static void send_from(struct test_params p, uint16_t sport, char *buf,
180 struct sockaddr * const saddr = new_any_sockaddr(p.send_family, sport);
181 struct sockaddr * const daddr =
182 new_loopback_sockaddr(p.send_family, p.recv_port);
183 const int fd = socket(p.send_family, p.protocol, 0);
186 error(1, errno, "failed to create send socket");
188 if (bind(fd, saddr, sockaddr_size()))
189 error(1, errno, "failed to bind send socket");
190 if (connect(fd, daddr, sockaddr_size()))
191 error(1, errno, "failed to connect");
193 if (send(fd, buf, len, 0) < 0)
194 error(1, errno, "failed to send message");
201 static void test_recv_order(const struct test_params p, int fd[], int mod)
203 char recv_buf[8], send_buf[8];
205 struct iovec recv_io = { recv_buf, 8 };
206 struct epoll_event ev;
207 int epfd, conn, i, sport, expected;
208 uint32_t data, ndata;
210 epfd = epoll_create(1);
212 error(1, errno, "failed to create epoll");
213 for (i = 0; i < p.recv_socks; ++i) {
216 if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd[i], &ev))
217 error(1, errno, "failed to register sock %d epoll", i);
220 memset(&msg, 0, sizeof(msg));
221 msg.msg_iov = &recv_io;
224 for (data = 0; data < p.recv_socks * 2; ++data) {
225 sport = p.send_port_min + data;
227 memcpy(send_buf, &ndata, sizeof(ndata));
228 send_from(p, sport, send_buf, sizeof(ndata));
230 i = epoll_wait(epfd, &ev, 1, -1);
232 error(1, errno, "epoll wait failed");
234 if (p.protocol == SOCK_STREAM) {
235 conn = accept(ev.data.fd, NULL, NULL);
237 error(1, errno, "error accepting");
238 i = recvmsg(conn, &msg, 0);
241 i = recvmsg(ev.data.fd, &msg, 0);
244 error(1, errno, "recvmsg error");
245 if (i != sizeof(ndata))
246 error(1, 0, "expected size %zd got %d",
249 for (i = 0; i < p.recv_socks; ++i)
250 if (ev.data.fd == fd[i])
252 memcpy(&ndata, recv_buf, sizeof(ndata));
253 fprintf(stderr, "Socket %d: %d\n", i, ntohl(ndata));
255 expected = (sport % mod);
257 error(1, 0, "expected socket %d", expected);
261 static void test_reuseport_ebpf(const struct test_params p)
263 int i, fd[p.recv_socks];
265 fprintf(stderr, "Testing EBPF mod %zd...\n", p.recv_socks);
266 build_recv_group(p, fd, p.recv_socks, attach_ebpf);
267 test_recv_order(p, fd, p.recv_socks);
269 fprintf(stderr, "Reprograming, testing mod %zd...\n", p.recv_socks / 2);
270 attach_ebpf(fd[0], p.recv_socks / 2);
271 test_recv_order(p, fd, p.recv_socks / 2);
273 for (i = 0; i < p.recv_socks; ++i)
277 static void test_reuseport_cbpf(const struct test_params p)
279 int i, fd[p.recv_socks];
281 fprintf(stderr, "Testing CBPF mod %zd...\n", p.recv_socks);
282 build_recv_group(p, fd, p.recv_socks, attach_cbpf);
283 test_recv_order(p, fd, p.recv_socks);
285 fprintf(stderr, "Reprograming, testing mod %zd...\n", p.recv_socks / 2);
286 attach_cbpf(fd[0], p.recv_socks / 2);
287 test_recv_order(p, fd, p.recv_socks / 2);
289 for (i = 0; i < p.recv_socks; ++i)
293 static void test_extra_filter(const struct test_params p)
295 struct sockaddr * const addr =
296 new_any_sockaddr(p.recv_family, p.recv_port);
299 fprintf(stderr, "Testing too many filters...\n");
300 fd1 = socket(p.recv_family, p.protocol, 0);
302 error(1, errno, "failed to create socket 1");
303 fd2 = socket(p.recv_family, p.protocol, 0);
305 error(1, errno, "failed to create socket 2");
308 if (setsockopt(fd1, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)))
309 error(1, errno, "failed to set SO_REUSEPORT on socket 1");
310 if (setsockopt(fd2, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)))
311 error(1, errno, "failed to set SO_REUSEPORT on socket 2");
313 attach_ebpf(fd1, 10);
314 attach_ebpf(fd2, 10);
316 if (bind(fd1, addr, sockaddr_size()))
317 error(1, errno, "failed to bind recv socket 1");
319 if (!bind(fd2, addr, sockaddr_size()) && errno != EADDRINUSE)
320 error(1, errno, "bind socket 2 should fail with EADDRINUSE");
325 static void test_filter_no_reuseport(const struct test_params p)
327 struct sockaddr * const addr =
328 new_any_sockaddr(p.recv_family, p.recv_port);
329 const char bpf_license[] = "GPL";
330 struct bpf_insn ecode[] = {
331 { BPF_ALU64 | BPF_MOV | BPF_K, BPF_REG_0, 0, 0, 10 },
332 { BPF_JMP | BPF_EXIT, 0, 0, 0, 0 }
334 struct sock_filter ccode[] = {{ BPF_RET | BPF_A, 0, 0, 0 }};
335 union bpf_attr eprog;
336 struct sock_fprog cprog;
339 fprintf(stderr, "Testing filters on non-SO_REUSEPORT socket...\n");
341 memset(&eprog, 0, sizeof(eprog));
342 eprog.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
343 eprog.insn_cnt = ARRAY_SIZE(ecode);
344 eprog.insns = (uint64_t)ecode;
345 eprog.license = (uint64_t)bpf_license;
346 eprog.kern_version = 0;
348 memset(&cprog, 0, sizeof(cprog));
349 cprog.len = ARRAY_SIZE(ccode);
350 cprog.filter = ccode;
353 bpf_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &eprog, sizeof(eprog));
355 error(1, errno, "ebpf error");
356 fd = socket(p.recv_family, p.protocol, 0);
358 error(1, errno, "failed to create socket 1");
360 if (bind(fd, addr, sockaddr_size()))
361 error(1, errno, "failed to bind recv socket 1");
364 if (!setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF, &bpf_fd,
365 sizeof(bpf_fd)) || errno != EINVAL)
366 error(1, errno, "setsockopt should have returned EINVAL");
369 if (!setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF, &cprog,
370 sizeof(cprog)) || errno != EINVAL)
371 error(1, errno, "setsockopt should have returned EINVAL");
376 static void test_filter_without_bind(void)
380 fprintf(stderr, "Testing filter add without bind...\n");
381 fd1 = socket(AF_INET, SOCK_DGRAM, 0);
383 error(1, errno, "failed to create socket 1");
384 fd2 = socket(AF_INET, SOCK_DGRAM, 0);
386 error(1, errno, "failed to create socket 2");
388 attach_ebpf(fd1, 10);
389 attach_cbpf(fd2, 10);
398 fprintf(stderr, "---- IPv4 UDP ----\n");
399 test_reuseport_ebpf((struct test_params) {
400 .recv_family = AF_INET,
401 .send_family = AF_INET,
402 .protocol = SOCK_DGRAM,
405 .send_port_min = 9000});
406 test_reuseport_cbpf((struct test_params) {
407 .recv_family = AF_INET,
408 .send_family = AF_INET,
409 .protocol = SOCK_DGRAM,
412 .send_port_min = 9020});
413 test_extra_filter((struct test_params) {
414 .recv_family = AF_INET,
415 .protocol = SOCK_DGRAM,
417 test_filter_no_reuseport((struct test_params) {
418 .recv_family = AF_INET,
419 .protocol = SOCK_DGRAM,
422 fprintf(stderr, "---- IPv6 UDP ----\n");
423 test_reuseport_ebpf((struct test_params) {
424 .recv_family = AF_INET6,
425 .send_family = AF_INET6,
426 .protocol = SOCK_DGRAM,
429 .send_port_min = 9040});
430 test_reuseport_cbpf((struct test_params) {
431 .recv_family = AF_INET6,
432 .send_family = AF_INET6,
433 .protocol = SOCK_DGRAM,
436 .send_port_min = 9060});
437 test_extra_filter((struct test_params) {
438 .recv_family = AF_INET6,
439 .protocol = SOCK_DGRAM,
441 test_filter_no_reuseport((struct test_params) {
442 .recv_family = AF_INET6,
443 .protocol = SOCK_DGRAM,
446 fprintf(stderr, "---- IPv6 UDP w/ mapped IPv4 ----\n");
447 test_reuseport_ebpf((struct test_params) {
448 .recv_family = AF_INET6,
449 .send_family = AF_INET,
450 .protocol = SOCK_DGRAM,
453 .send_port_min = 9080});
454 test_reuseport_cbpf((struct test_params) {
455 .recv_family = AF_INET6,
456 .send_family = AF_INET,
457 .protocol = SOCK_DGRAM,
460 .send_port_min = 9100});
463 test_filter_without_bind();
465 fprintf(stderr, "SUCCESS\n");