600 lines · c
1// SPDX-License-Identifier: GPL-2.02 3#define _GNU_SOURCE4 5#include <assert.h>6#include <errno.h>7#include <fcntl.h>8#include <limits.h>9#include <string.h>10#include <stdarg.h>11#include <stdbool.h>12#include <stdint.h>13#include <inttypes.h>14#include <stdio.h>15#include <stdlib.h>16#include <strings.h>17#include <unistd.h>18#include <time.h>19 20#include <sys/ioctl.h>21#include <sys/random.h>22#include <sys/socket.h>23#include <sys/types.h>24#include <sys/wait.h>25 26#include <netdb.h>27#include <netinet/in.h>28 29#include <linux/tcp.h>30#include <linux/sockios.h>31 32#ifndef IPPROTO_MPTCP33#define IPPROTO_MPTCP 26234#endif35#ifndef SOL_MPTCP36#define SOL_MPTCP 28437#endif38 39static int pf = AF_INET;40static int proto_tx = IPPROTO_MPTCP;41static int proto_rx = IPPROTO_MPTCP;42 43static void die_perror(const char *msg)44{45 perror(msg);46 exit(1);47}48 49static void die_usage(int r)50{51 fprintf(stderr, "Usage: mptcp_inq [-6] [ -t tcp|mptcp ] [ -r tcp|mptcp]\n");52 exit(r);53}54 55static void xerror(const char *fmt, ...)56{57 va_list ap;58 59 va_start(ap, fmt);60 vfprintf(stderr, fmt, ap);61 va_end(ap);62 fputc('\n', stderr);63 exit(1);64}65 66static const char *getxinfo_strerr(int err)67{68 if (err == EAI_SYSTEM)69 return strerror(errno);70 71 return gai_strerror(err);72}73 74static void xgetaddrinfo(const char *node, const char *service,75 const struct addrinfo *hints,76 struct addrinfo **res)77{78 int err = getaddrinfo(node, service, hints, res);79 80 if (err) {81 const char *errstr = getxinfo_strerr(err);82 83 fprintf(stderr, "Fatal: getaddrinfo(%s:%s): %s\n",84 node ? node : "", service ? service : "", errstr);85 exit(1);86 }87}88 89static int sock_listen_mptcp(const char * const listenaddr,90 const char * const port)91{92 int sock = -1;93 struct addrinfo hints = {94 .ai_protocol = IPPROTO_TCP,95 .ai_socktype = SOCK_STREAM,96 .ai_flags = AI_PASSIVE | AI_NUMERICHOST97 };98 99 hints.ai_family = pf;100 101 struct addrinfo *a, *addr;102 int one = 1;103 104 xgetaddrinfo(listenaddr, port, &hints, &addr);105 hints.ai_family = pf;106 107 for (a = addr; a; a = a->ai_next) {108 sock = socket(a->ai_family, a->ai_socktype, proto_rx);109 if (sock < 0)110 continue;111 112 if (-1 == setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one,113 sizeof(one)))114 perror("setsockopt");115 116 if (bind(sock, a->ai_addr, a->ai_addrlen) == 0)117 break; /* success */118 119 perror("bind");120 close(sock);121 sock = -1;122 }123 124 freeaddrinfo(addr);125 126 if (sock < 0)127 xerror("could not create listen socket");128 129 if (listen(sock, 20))130 die_perror("listen");131 132 return sock;133}134 135static int sock_connect_mptcp(const char * const remoteaddr,136 const char * const port, int proto)137{138 struct addrinfo hints = {139 .ai_protocol = IPPROTO_TCP,140 .ai_socktype = SOCK_STREAM,141 };142 struct addrinfo *a, *addr;143 int sock = -1;144 145 hints.ai_family = pf;146 147 xgetaddrinfo(remoteaddr, port, &hints, &addr);148 for (a = addr; a; a = a->ai_next) {149 sock = socket(a->ai_family, a->ai_socktype, proto);150 if (sock < 0)151 continue;152 153 if (connect(sock, a->ai_addr, a->ai_addrlen) == 0)154 break; /* success */155 156 die_perror("connect");157 }158 159 if (sock < 0)160 xerror("could not create connect socket");161 162 freeaddrinfo(addr);163 return sock;164}165 166static int protostr_to_num(const char *s)167{168 if (strcasecmp(s, "tcp") == 0)169 return IPPROTO_TCP;170 if (strcasecmp(s, "mptcp") == 0)171 return IPPROTO_MPTCP;172 173 die_usage(1);174 return 0;175}176 177static void parse_opts(int argc, char **argv)178{179 int c;180 181 while ((c = getopt(argc, argv, "h6t:r:")) != -1) {182 switch (c) {183 case 'h':184 die_usage(0);185 break;186 case '6':187 pf = AF_INET6;188 break;189 case 't':190 proto_tx = protostr_to_num(optarg);191 break;192 case 'r':193 proto_rx = protostr_to_num(optarg);194 break;195 default:196 die_usage(1);197 break;198 }199 }200}201 202/* wait up to timeout milliseconds */203static void wait_for_ack(int fd, int timeout, size_t total)204{205 int i;206 207 for (i = 0; i < timeout; i++) {208 int nsd, ret, queued = -1;209 struct timespec req;210 211 ret = ioctl(fd, TIOCOUTQ, &queued);212 if (ret < 0)213 die_perror("TIOCOUTQ");214 215 ret = ioctl(fd, SIOCOUTQNSD, &nsd);216 if (ret < 0)217 die_perror("SIOCOUTQNSD");218 219 if ((size_t)queued > total)220 xerror("TIOCOUTQ %u, but only %zu expected\n", queued, total);221 assert(nsd <= queued);222 223 if (queued == 0)224 return;225 226 /* wait for peer to ack rx of all data */227 req.tv_sec = 0;228 req.tv_nsec = 1 * 1000 * 1000ul; /* 1ms */229 nanosleep(&req, NULL);230 }231 232 xerror("still tx data queued after %u ms\n", timeout);233}234 235static void connect_one_server(int fd, int unixfd)236{237 size_t len, i, total, sent;238 char buf[4096], buf2[4096];239 ssize_t ret;240 241 len = rand() % (sizeof(buf) - 1);242 243 if (len < 128)244 len = 128;245 246 for (i = 0; i < len ; i++) {247 buf[i] = rand() % 26;248 buf[i] += 'A';249 }250 251 buf[i] = '\n';252 253 /* un-block server */254 ret = read(unixfd, buf2, 4);255 assert(ret == 4);256 257 assert(strncmp(buf2, "xmit", 4) == 0);258 259 ret = write(unixfd, &len, sizeof(len));260 assert(ret == (ssize_t)sizeof(len));261 262 ret = write(fd, buf, len);263 if (ret < 0)264 die_perror("write");265 266 if (ret != (ssize_t)len)267 xerror("short write");268 269 ret = read(unixfd, buf2, 4);270 assert(strncmp(buf2, "huge", 4) == 0);271 272 total = rand() % (16 * 1024 * 1024);273 total += (1 * 1024 * 1024);274 sent = total;275 276 ret = write(unixfd, &total, sizeof(total));277 assert(ret == (ssize_t)sizeof(total));278 279 wait_for_ack(fd, 5000, len);280 281 while (total > 0) {282 if (total > sizeof(buf))283 len = sizeof(buf);284 else285 len = total;286 287 ret = write(fd, buf, len);288 if (ret < 0)289 die_perror("write");290 total -= ret;291 292 /* we don't have to care about buf content, only293 * number of total bytes sent294 */295 }296 297 ret = read(unixfd, buf2, 4);298 assert(ret == 4);299 assert(strncmp(buf2, "shut", 4) == 0);300 301 wait_for_ack(fd, 5000, sent);302 303 ret = write(fd, buf, 1);304 assert(ret == 1);305 close(fd);306 ret = write(unixfd, "closed", 6);307 assert(ret == 6);308 309 close(unixfd);310}311 312static void get_tcp_inq(struct msghdr *msgh, unsigned int *inqv)313{314 struct cmsghdr *cmsg;315 316 for (cmsg = CMSG_FIRSTHDR(msgh); cmsg ; cmsg = CMSG_NXTHDR(msgh, cmsg)) {317 if (cmsg->cmsg_level == IPPROTO_TCP && cmsg->cmsg_type == TCP_CM_INQ) {318 memcpy(inqv, CMSG_DATA(cmsg), sizeof(*inqv));319 return;320 }321 }322 323 xerror("could not find TCP_CM_INQ cmsg type");324}325 326static void process_one_client(int fd, int unixfd)327{328 unsigned int tcp_inq;329 size_t expect_len;330 char msg_buf[4096];331 char buf[4096];332 char tmp[16];333 struct iovec iov = {334 .iov_base = buf,335 .iov_len = 1,336 };337 struct msghdr msg = {338 .msg_iov = &iov,339 .msg_iovlen = 1,340 .msg_control = msg_buf,341 .msg_controllen = sizeof(msg_buf),342 };343 ssize_t ret, tot;344 345 ret = write(unixfd, "xmit", 4);346 assert(ret == 4);347 348 ret = read(unixfd, &expect_len, sizeof(expect_len));349 assert(ret == (ssize_t)sizeof(expect_len));350 351 if (expect_len > sizeof(buf))352 xerror("expect len %zu exceeds buffer size", expect_len);353 354 for (;;) {355 struct timespec req;356 unsigned int queued;357 358 ret = ioctl(fd, FIONREAD, &queued);359 if (ret < 0)360 die_perror("FIONREAD");361 if (queued > expect_len)362 xerror("FIONREAD returned %u, but only %zu expected\n",363 queued, expect_len);364 if (queued == expect_len)365 break;366 367 req.tv_sec = 0;368 req.tv_nsec = 1000 * 1000ul;369 nanosleep(&req, NULL);370 }371 372 /* read one byte, expect cmsg to return expected - 1 */373 ret = recvmsg(fd, &msg, 0);374 if (ret < 0)375 die_perror("recvmsg");376 377 if (msg.msg_controllen == 0)378 xerror("msg_controllen is 0");379 380 get_tcp_inq(&msg, &tcp_inq);381 382 assert((size_t)tcp_inq == (expect_len - 1));383 384 iov.iov_len = sizeof(buf);385 ret = recvmsg(fd, &msg, 0);386 if (ret < 0)387 die_perror("recvmsg");388 389 /* should have gotten exact remainder of all pending data */390 assert(ret == (ssize_t)tcp_inq);391 392 /* should be 0, all drained */393 get_tcp_inq(&msg, &tcp_inq);394 assert(tcp_inq == 0);395 396 /* request a large swath of data. */397 ret = write(unixfd, "huge", 4);398 assert(ret == 4);399 400 ret = read(unixfd, &expect_len, sizeof(expect_len));401 assert(ret == (ssize_t)sizeof(expect_len));402 403 /* peer should send us a few mb of data */404 if (expect_len <= sizeof(buf))405 xerror("expect len %zu too small\n", expect_len);406 407 tot = 0;408 do {409 iov.iov_len = sizeof(buf);410 ret = recvmsg(fd, &msg, 0);411 if (ret < 0)412 die_perror("recvmsg");413 414 tot += ret;415 416 get_tcp_inq(&msg, &tcp_inq);417 418 if (tcp_inq > expect_len - tot)419 xerror("inq %d, remaining %d total_len %d\n",420 tcp_inq, expect_len - tot, (int)expect_len);421 422 assert(tcp_inq <= expect_len - tot);423 } while ((size_t)tot < expect_len);424 425 ret = write(unixfd, "shut", 4);426 assert(ret == 4);427 428 /* wait for hangup. Should have received one more byte of data. */429 ret = read(unixfd, tmp, sizeof(tmp));430 assert(ret == 6);431 assert(strncmp(tmp, "closed", 6) == 0);432 433 sleep(1);434 435 iov.iov_len = 1;436 ret = recvmsg(fd, &msg, 0);437 if (ret < 0)438 die_perror("recvmsg");439 assert(ret == 1);440 441 get_tcp_inq(&msg, &tcp_inq);442 443 /* tcp_inq should be 1 due to received fin. */444 assert(tcp_inq == 1);445 446 iov.iov_len = 1;447 ret = recvmsg(fd, &msg, 0);448 if (ret < 0)449 die_perror("recvmsg");450 451 /* expect EOF */452 assert(ret == 0);453 get_tcp_inq(&msg, &tcp_inq);454 assert(tcp_inq == 1);455 456 close(fd);457}458 459static int xaccept(int s)460{461 int fd = accept(s, NULL, 0);462 463 if (fd < 0)464 die_perror("accept");465 466 return fd;467}468 469static int server(int unixfd)470{471 int fd = -1, r, on = 1;472 473 switch (pf) {474 case AF_INET:475 fd = sock_listen_mptcp("127.0.0.1", "15432");476 break;477 case AF_INET6:478 fd = sock_listen_mptcp("::1", "15432");479 break;480 default:481 xerror("Unknown pf %d\n", pf);482 break;483 }484 485 r = write(unixfd, "conn", 4);486 assert(r == 4);487 488 alarm(15);489 r = xaccept(fd);490 491 if (-1 == setsockopt(r, IPPROTO_TCP, TCP_INQ, &on, sizeof(on)))492 die_perror("setsockopt");493 494 process_one_client(r, unixfd);495 496 return 0;497}498 499static int client(int unixfd)500{501 int fd = -1;502 503 alarm(15);504 505 switch (pf) {506 case AF_INET:507 fd = sock_connect_mptcp("127.0.0.1", "15432", proto_tx);508 break;509 case AF_INET6:510 fd = sock_connect_mptcp("::1", "15432", proto_tx);511 break;512 default:513 xerror("Unknown pf %d\n", pf);514 }515 516 connect_one_server(fd, unixfd);517 518 return 0;519}520 521static void init_rng(void)522{523 unsigned int foo;524 525 if (getrandom(&foo, sizeof(foo), 0) == -1) {526 perror("getrandom");527 exit(1);528 }529 530 srand(foo);531}532 533static pid_t xfork(void)534{535 pid_t p = fork();536 537 if (p < 0)538 die_perror("fork");539 else if (p == 0)540 init_rng();541 542 return p;543}544 545static int rcheck(int wstatus, const char *what)546{547 if (WIFEXITED(wstatus)) {548 if (WEXITSTATUS(wstatus) == 0)549 return 0;550 fprintf(stderr, "%s exited, status=%d\n", what, WEXITSTATUS(wstatus));551 return WEXITSTATUS(wstatus);552 } else if (WIFSIGNALED(wstatus)) {553 xerror("%s killed by signal %d\n", what, WTERMSIG(wstatus));554 } else if (WIFSTOPPED(wstatus)) {555 xerror("%s stopped by signal %d\n", what, WSTOPSIG(wstatus));556 }557 558 return 111;559}560 561int main(int argc, char *argv[])562{563 int e1, e2, wstatus;564 pid_t s, c, ret;565 int unixfds[2];566 567 parse_opts(argc, argv);568 569 e1 = socketpair(AF_UNIX, SOCK_DGRAM, 0, unixfds);570 if (e1 < 0)571 die_perror("pipe");572 573 s = xfork();574 if (s == 0)575 return server(unixfds[1]);576 577 close(unixfds[1]);578 579 /* wait until server bound a socket */580 e1 = read(unixfds[0], &e1, 4);581 assert(e1 == 4);582 583 c = xfork();584 if (c == 0)585 return client(unixfds[0]);586 587 close(unixfds[0]);588 589 ret = waitpid(s, &wstatus, 0);590 if (ret == -1)591 die_perror("waitpid");592 e1 = rcheck(wstatus, "server");593 ret = waitpid(c, &wstatus, 0);594 if (ret == -1)595 die_perror("waitpid");596 e2 = rcheck(wstatus, "client");597 598 return e1 ? e1 : e2;599}600