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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 | // SPDX-License-Identifier: GPL-2.0-only /* * Copyright 2018 Google Inc. * Author: Soheil Hassas Yeganeh (soheil@google.com) * * Simple example on how to use TCP_INQ and TCP_CM_INQ. */ #define _GNU_SOURCE #include <error.h> #include <netinet/in.h> #include <netinet/tcp.h> #include <pthread.h> #include <stdio.h> #include <errno.h> #include <stdlib.h> #include <string.h> #include <sys/socket.h> #include <unistd.h> #ifndef TCP_INQ #define TCP_INQ 36 #endif #ifndef TCP_CM_INQ #define TCP_CM_INQ TCP_INQ #endif #define BUF_SIZE 8192 #define CMSG_SIZE 32 static int family = AF_INET6; static socklen_t addr_len = sizeof(struct sockaddr_in6); static int port = 4974; static void setup_loopback_addr(int family, struct sockaddr_storage *sockaddr) { struct sockaddr_in6 *addr6 = (void *) sockaddr; struct sockaddr_in *addr4 = (void *) sockaddr; switch (family) { case PF_INET: memset(addr4, 0, sizeof(*addr4)); addr4->sin_family = AF_INET; addr4->sin_addr.s_addr = htonl(INADDR_LOOPBACK); addr4->sin_port = htons(port); break; case PF_INET6: memset(addr6, 0, sizeof(*addr6)); addr6->sin6_family = AF_INET6; addr6->sin6_addr = in6addr_loopback; addr6->sin6_port = htons(port); break; default: error(1, 0, "illegal family"); } } void *start_server(void *arg) { int server_fd = (int)(unsigned long)arg; struct sockaddr_in addr; socklen_t addrlen = sizeof(addr); char *buf; int fd; int r; buf = malloc(BUF_SIZE); for (;;) { fd = accept(server_fd, (struct sockaddr *)&addr, &addrlen); if (fd == -1) { perror("accept"); break; } do { r = send(fd, buf, BUF_SIZE, 0); } while (r < 0 && errno == EINTR); if (r < 0) perror("send"); if (r != BUF_SIZE) fprintf(stderr, "can only send %d bytes\n", r); /* TCP_INQ can overestimate in-queue by one byte if we send * the FIN packet. Sleep for 1 second, so that the client * likely invoked recvmsg(). */ sleep(1); close(fd); } free(buf); close(server_fd); pthread_exit(0); } int main(int argc, char *argv[]) { struct sockaddr_storage listen_addr, addr; int c, one = 1, inq = -1; pthread_t server_thread; char cmsgbuf[CMSG_SIZE]; struct iovec iov[1]; struct cmsghdr *cm; struct msghdr msg; int server_fd, fd; char *buf; while ((c = getopt(argc, argv, "46p:")) != -1) { switch (c) { case '4': family = PF_INET; addr_len = sizeof(struct sockaddr_in); break; case '6': family = PF_INET6; addr_len = sizeof(struct sockaddr_in6); break; case 'p': port = atoi(optarg); break; } } server_fd = socket(family, SOCK_STREAM, 0); if (server_fd < 0) error(1, errno, "server socket"); setup_loopback_addr(family, &listen_addr); if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) != 0) error(1, errno, "setsockopt(SO_REUSEADDR)"); if (bind(server_fd, (const struct sockaddr *)&listen_addr, addr_len) == -1) error(1, errno, "bind"); if (listen(server_fd, 128) == -1) error(1, errno, "listen"); if (pthread_create(&server_thread, NULL, start_server, (void *)(unsigned long)server_fd) != 0) error(1, errno, "pthread_create"); fd = socket(family, SOCK_STREAM, 0); if (fd < 0) error(1, errno, "client socket"); setup_loopback_addr(family, &addr); if (connect(fd, (const struct sockaddr *)&addr, addr_len) == -1) error(1, errno, "connect"); if (setsockopt(fd, SOL_TCP, TCP_INQ, &one, sizeof(one)) != 0) error(1, errno, "setsockopt(TCP_INQ)"); msg.msg_name = NULL; msg.msg_namelen = 0; msg.msg_iov = iov; msg.msg_iovlen = 1; msg.msg_control = cmsgbuf; msg.msg_controllen = sizeof(cmsgbuf); msg.msg_flags = 0; buf = malloc(BUF_SIZE); iov[0].iov_base = buf; iov[0].iov_len = BUF_SIZE / 2; if (recvmsg(fd, &msg, 0) != iov[0].iov_len) error(1, errno, "recvmsg"); if (msg.msg_flags & MSG_CTRUNC) error(1, 0, "control message is truncated"); for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) if (cm->cmsg_level == SOL_TCP && cm->cmsg_type == TCP_CM_INQ) inq = *((int *) CMSG_DATA(cm)); if (inq != BUF_SIZE - iov[0].iov_len) { fprintf(stderr, "unexpected inq: %d\n", inq); exit(1); } printf("PASSED\n"); free(buf); close(fd); return 0; } |