1 // SPDX-License-Identifier: GPL-2.0
9 #include <netinet/ip.h>
10 #include <netinet/ip6.h>
11 #include <netinet/udp.h>
19 static bool cfg_do_ipv4;
20 static bool cfg_do_ipv6;
21 static bool cfg_verbose;
22 static bool cfg_overlap;
23 static unsigned short cfg_port = 9000;
25 const struct in_addr addr4 = { .s_addr = __constant_htonl(INADDR_LOOPBACK + 2) };
26 const struct in6_addr addr6 = IN6ADDR_LOOPBACK_INIT;
28 #define IP4_HLEN (sizeof(struct iphdr))
29 #define IP6_HLEN (sizeof(struct ip6_hdr))
30 #define UDP_HLEN (sizeof(struct udphdr))
32 /* IPv6 fragment header lenth. */
35 static int payload_len;
36 static int max_frag_len;
38 #define MSG_LEN_MAX 60000 /* Max UDP payload length. */
40 #define IP4_MF (1u << 13) /* IPv4 MF flag. */
41 #define IP6_MF (1) /* IPv6 MF flag. */
43 #define CSUM_MANGLED_0 (0xffff)
45 static uint8_t udp_payload[MSG_LEN_MAX];
46 static uint8_t ip_frame[IP_MAXPACKET];
47 static uint32_t ip_id = 0xabcd;
48 static int msg_counter;
49 static int frag_counter;
50 static unsigned int seed;
52 /* Receive a UDP packet. Validate it matches udp_payload. */
53 static void recv_validate_udp(int fd_udp)
56 static uint8_t recv_buff[MSG_LEN_MAX];
58 ret = recv(fd_udp, recv_buff, payload_len, 0);
63 error(1, 0, "recv: expected timeout; got %d",
65 if (errno != ETIMEDOUT && errno != EAGAIN)
66 error(1, errno, "recv: expected timeout: %d",
72 error(1, errno, "recv: payload_len = %d max_frag_len = %d",
73 payload_len, max_frag_len);
74 if (ret != payload_len)
75 error(1, 0, "recv: wrong size: %d vs %d", (int)ret, payload_len);
76 if (memcmp(udp_payload, recv_buff, payload_len))
77 error(1, 0, "recv: wrong data");
80 static uint32_t raw_checksum(uint8_t *buf, int len, uint32_t sum)
84 for (i = 0; i < (len & ~1U); i += 2) {
85 sum += (u_int16_t)ntohs(*((u_int16_t *)(buf + i)));
99 static uint16_t udp_checksum(struct ip *iphdr, struct udphdr *udphdr)
104 sum = raw_checksum((uint8_t *)&iphdr->ip_src, 2 * sizeof(iphdr->ip_src),
105 IPPROTO_UDP + (uint32_t)(UDP_HLEN + payload_len));
106 sum = raw_checksum((uint8_t *)udphdr, UDP_HLEN, sum);
107 sum = raw_checksum((uint8_t *)udp_payload, payload_len, sum);
112 return CSUM_MANGLED_0;
115 static uint16_t udp6_checksum(struct ip6_hdr *iphdr, struct udphdr *udphdr)
120 sum = raw_checksum((uint8_t *)&iphdr->ip6_src, 2 * sizeof(iphdr->ip6_src),
122 sum = raw_checksum((uint8_t *)&udphdr->len, sizeof(udphdr->len), sum);
123 sum = raw_checksum((uint8_t *)udphdr, UDP_HLEN, sum);
124 sum = raw_checksum((uint8_t *)udp_payload, payload_len, sum);
129 return CSUM_MANGLED_0;
132 static void send_fragment(int fd_raw, struct sockaddr *addr, socklen_t alen,
133 int offset, bool ipv6)
137 int payload_offset = offset > 0 ? offset - UDP_HLEN : 0;
138 uint8_t *frag_start = ipv6 ? ip_frame + IP6_HLEN + FRAG_HLEN :
142 struct udphdr udphdr;
143 udphdr.source = htons(cfg_port + 1);
144 udphdr.dest = htons(cfg_port);
145 udphdr.len = htons(UDP_HLEN + payload_len);
148 udphdr.check = udp6_checksum((struct ip6_hdr *)ip_frame, &udphdr);
150 udphdr.check = udp_checksum((struct ip *)ip_frame, &udphdr);
151 memcpy(frag_start, &udphdr, UDP_HLEN);
155 struct ip6_hdr *ip6hdr = (struct ip6_hdr *)ip_frame;
156 struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
157 if (payload_len - payload_offset <= max_frag_len && offset > 0) {
158 /* This is the last fragment. */
159 frag_len = FRAG_HLEN + payload_len - payload_offset;
160 fraghdr->ip6f_offlg = htons(offset);
162 frag_len = FRAG_HLEN + max_frag_len;
163 fraghdr->ip6f_offlg = htons(offset | IP6_MF);
165 ip6hdr->ip6_plen = htons(frag_len);
167 memcpy(frag_start + UDP_HLEN, udp_payload,
168 frag_len - FRAG_HLEN - UDP_HLEN);
170 memcpy(frag_start, udp_payload + payload_offset,
171 frag_len - FRAG_HLEN);
172 frag_len += IP6_HLEN;
174 struct ip *iphdr = (struct ip *)ip_frame;
175 if (payload_len - payload_offset <= max_frag_len && offset > 0) {
176 /* This is the last fragment. */
177 frag_len = IP4_HLEN + payload_len - payload_offset;
178 iphdr->ip_off = htons(offset / 8);
180 frag_len = IP4_HLEN + max_frag_len;
181 iphdr->ip_off = htons(offset / 8 | IP4_MF);
183 iphdr->ip_len = htons(frag_len);
185 memcpy(frag_start + UDP_HLEN, udp_payload,
186 frag_len - IP4_HLEN - UDP_HLEN);
188 memcpy(frag_start, udp_payload + payload_offset,
189 frag_len - IP4_HLEN);
192 res = sendto(fd_raw, ip_frame, frag_len, 0, addr, alen);
194 error(1, errno, "send_fragment");
196 error(1, 0, "send_fragment: %d vs %d", res, frag_len);
201 static void send_udp_frags(int fd_raw, struct sockaddr *addr,
202 socklen_t alen, bool ipv6)
204 struct ip *iphdr = (struct ip *)ip_frame;
205 struct ip6_hdr *ip6hdr = (struct ip6_hdr *)ip_frame;
206 const bool ipv4 = !ipv6;
211 /* Send the UDP datagram using raw IP fragments: the 0th fragment
212 * has the UDP header; other fragments are pieces of udp_payload
213 * split in chunks of frag_len size.
215 * Odd fragments (1st, 3rd, 5th, etc.) are sent out first, then
216 * even fragments (0th, 2nd, etc.) are sent out.
219 struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
220 ((struct sockaddr_in6 *)addr)->sin6_port = 0;
221 memset(ip6hdr, 0, sizeof(*ip6hdr));
222 ip6hdr->ip6_flow = htonl(6<<28); /* Version. */
223 ip6hdr->ip6_nxt = IPPROTO_FRAGMENT;
224 ip6hdr->ip6_hops = 255;
225 ip6hdr->ip6_src = addr6;
226 ip6hdr->ip6_dst = addr6;
227 fraghdr->ip6f_nxt = IPPROTO_UDP;
228 fraghdr->ip6f_reserved = 0;
229 fraghdr->ip6f_ident = htonl(ip_id++);
231 memset(iphdr, 0, sizeof(*iphdr));
235 iphdr->ip_id = htons(ip_id++);
236 iphdr->ip_ttl = 0x40;
237 iphdr->ip_p = IPPROTO_UDP;
238 iphdr->ip_src.s_addr = htonl(INADDR_LOOPBACK);
239 iphdr->ip_dst = addr4;
243 /* Occasionally test in-order fragments. */
244 if (!cfg_overlap && (rand() % 100 < 15)) {
246 while (offset < (UDP_HLEN + payload_len)) {
247 send_fragment(fd_raw, addr, alen, offset, ipv6);
248 offset += max_frag_len;
253 /* Occasionally test IPv4 "runs" (see net/ipv4/ip_fragment.c) */
254 if (ipv4 && !cfg_overlap && (rand() % 100 < 20) &&
255 (payload_len > 9 * max_frag_len)) {
256 offset = 6 * max_frag_len;
257 while (offset < (UDP_HLEN + payload_len)) {
258 send_fragment(fd_raw, addr, alen, offset, ipv6);
259 offset += max_frag_len;
261 offset = 3 * max_frag_len;
262 while (offset < 6 * max_frag_len) {
263 send_fragment(fd_raw, addr, alen, offset, ipv6);
264 offset += max_frag_len;
267 while (offset < 3 * max_frag_len) {
268 send_fragment(fd_raw, addr, alen, offset, ipv6);
269 offset += max_frag_len;
275 offset = max_frag_len;
276 while (offset < (UDP_HLEN + payload_len)) {
277 send_fragment(fd_raw, addr, alen, offset, ipv6);
278 /* IPv4 ignores duplicates, so randomly send a duplicate. */
279 if (ipv4 && (1 == rand() % 100))
280 send_fragment(fd_raw, addr, alen, offset, ipv6);
281 offset += 2 * max_frag_len;
285 /* Send an extra random fragment. */
287 struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
288 /* sendto() returns EINVAL if offset + frag_len is too small. */
289 offset = rand() % (UDP_HLEN + payload_len - 1);
290 frag_len = max_frag_len + rand() % 256;
291 /* In IPv6 if !!(frag_len % 8), the fragment is dropped. */
293 fraghdr->ip6f_offlg = htons(offset / 8 | IP6_MF);
294 ip6hdr->ip6_plen = htons(frag_len);
295 frag_len += IP6_HLEN;
297 /* In IPv4, duplicates and some fragments completely inside
298 * previously sent fragments are dropped/ignored. So
299 * random offset and frag_len can result in a dropped
300 * fragment instead of a dropped queue/packet. So we
301 * hard-code offset and frag_len.
303 * See ade446403bfb ("net: ipv4: do not handle duplicate
304 * fragments as overlapping").
306 if (max_frag_len * 4 < payload_len || max_frag_len < 16) {
307 /* not enough payload to play with random offset and frag_len. */
309 frag_len = IP4_HLEN + UDP_HLEN + max_frag_len;
311 offset = rand() % (payload_len / 2);
312 frag_len = 2 * max_frag_len + 1 + rand() % 256;
314 iphdr->ip_off = htons(offset / 8 | IP4_MF);
315 iphdr->ip_len = htons(frag_len);
317 res = sendto(fd_raw, ip_frame, frag_len, 0, addr, alen);
319 error(1, errno, "sendto overlap: %d", frag_len);
321 error(1, 0, "sendto overlap: %d vs %d", (int)res, frag_len);
325 /* Event fragments. */
327 while (offset < (UDP_HLEN + payload_len)) {
328 send_fragment(fd_raw, addr, alen, offset, ipv6);
329 /* IPv4 ignores duplicates, so randomly send a duplicate. */
330 if (ipv4 && (1 == rand() % 100))
331 send_fragment(fd_raw, addr, alen, offset, ipv6);
332 offset += 2 * max_frag_len;
336 static void run_test(struct sockaddr *addr, socklen_t alen, bool ipv6)
338 int fd_tx_raw, fd_rx_udp;
339 /* Frag queue timeout is set to one second in the calling script;
340 * socket timeout should be just a bit longer to avoid tests interfering
343 struct timeval tv = { .tv_sec = 1, .tv_usec = 10 };
345 int min_frag_len = ipv6 ? 1280 : 8;
347 /* Initialize the payload. */
348 for (idx = 0; idx < MSG_LEN_MAX; ++idx)
349 udp_payload[idx] = idx % 256;
352 fd_tx_raw = socket(addr->sa_family, SOCK_RAW, IPPROTO_RAW);
354 error(1, errno, "socket tx_raw");
356 fd_rx_udp = socket(addr->sa_family, SOCK_DGRAM, 0);
358 error(1, errno, "socket rx_udp");
359 if (bind(fd_rx_udp, addr, alen))
360 error(1, errno, "bind");
362 if (setsockopt(fd_rx_udp, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
363 error(1, errno, "setsockopt rcv timeout");
365 for (payload_len = min_frag_len; payload_len < MSG_LEN_MAX;
366 payload_len += (rand() % 4096)) {
368 printf("payload_len: %d\n", payload_len);
371 /* With overlaps, one send/receive pair below takes
372 * at least one second (== timeout) to run, so there
373 * is not enough test time to run a nested loop:
374 * the full overlap test takes 20-30 seconds.
376 max_frag_len = min_frag_len +
377 rand() % (1500 - FRAG_HLEN - min_frag_len);
378 send_udp_frags(fd_tx_raw, addr, alen, ipv6);
379 recv_validate_udp(fd_rx_udp);
381 /* Without overlaps, each packet reassembly (== one
382 * send/receive pair below) takes very little time to
383 * run, so we can easily afford more thourough testing
384 * with a nested loop: the full non-overlap test takes
385 * less than one second).
387 max_frag_len = min_frag_len;
389 send_udp_frags(fd_tx_raw, addr, alen, ipv6);
390 recv_validate_udp(fd_rx_udp);
391 max_frag_len += 8 * (rand() % 8);
392 } while (max_frag_len < (1500 - FRAG_HLEN) &&
393 max_frag_len <= payload_len);
398 if (close(fd_tx_raw))
399 error(1, errno, "close tx_raw");
400 if (close(fd_rx_udp))
401 error(1, errno, "close rx_udp");
404 printf("processed %d messages, %d fragments\n",
405 msg_counter, frag_counter);
407 fprintf(stderr, "PASS\n");
411 static void run_test_v4(void)
413 struct sockaddr_in addr = {0};
415 addr.sin_family = AF_INET;
416 addr.sin_port = htons(cfg_port);
417 addr.sin_addr = addr4;
419 run_test((void *)&addr, sizeof(addr), false /* !ipv6 */);
422 static void run_test_v6(void)
424 struct sockaddr_in6 addr = {0};
426 addr.sin6_family = AF_INET6;
427 addr.sin6_port = htons(cfg_port);
428 addr.sin6_addr = addr6;
430 run_test((void *)&addr, sizeof(addr), true /* ipv6 */);
433 static void parse_opts(int argc, char **argv)
437 while ((c = getopt(argc, argv, "46ov")) != -1) {
452 error(1, 0, "%s: parse error", argv[0]);
457 int main(int argc, char **argv)
459 parse_opts(argc, argv);
462 /* Print the seed to track/reproduce potential failures. */
463 printf("seed = %d\n", seed);