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| 1 | #include <cstdio> | |
| 2 | #include <cstdlib> | |
| 3 | ||
| 4 | #include <unistd.h> | |
| 5 | #include <errno.h> | |
| 6 | ||
| 7 | #include <sys/types.h> | |
| 8 | #include <sys/socket.h> | |
| 9 | #include <netinet/in.h> | |
| 10 | ||
| 11 | #include <netdb.h> | |
| 12 | #include <arpa/inet.h> | |
| 13 | ||
| 14 | int create_socket(bool server = false) | |
| 15 | {
| |
| 16 | addrinfo hints = {};
| |
| 17 | addrinfo* servinfo; | |
| 18 | ||
| 19 | int sockfd = -1; | |
| 20 | int rv; | |
| 21 | ||
| 22 | hints.ai_family = AF_INET; | |
| 23 | hints.ai_socktype = SOCK_STREAM; | |
| 24 | hints.ai_flags = server ? AI_PASSIVE : 0; | |
| 25 | ||
| 26 | if ((rv = getaddrinfo(server ? 0 : "localhost", "12345", &hints, &servinfo))) | |
| 27 | {
| |
| 28 | printf("getaddrinfo failed: %s\n", gai_strerror(rv));
| |
| 29 | exit(1); | |
| 30 | } | |
| 31 | ||
| 32 | for(auto p = servinfo; p; p = p->ai_next) | |
| 33 | {
| |
| 34 | if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) | |
| 35 | {
| |
| 36 | perror("socket");
| |
| 37 | continue; | |
| 38 | } | |
| 39 | ||
| 40 | if(server) | |
| 41 | {
| |
| 42 | int yes = 1; | |
| 43 | setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)); | |
| 44 | ||
| 45 | if(bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) | |
| 46 | {
| |
| 47 | close(sockfd); | |
| 48 | perror("bind");
| |
| 49 | continue; | |
| 50 | } | |
| 51 | } | |
| 52 | else | |
| 53 | {
| |
| 54 | if(connect(sockfd, p->ai_addr, p->ai_addrlen) == -1) | |
| 55 | {
| |
| 56 | close(sockfd); | |
| 57 | perror("connect");
| |
| 58 | continue; | |
| 59 | } | |
| 60 | else | |
| 61 | puts("client: connected");
| |
| 62 | } | |
| 63 | ||
| 64 | break; | |
| 65 | } | |
| 66 | ||
| 67 | freeaddrinfo(servinfo); | |
| 68 | return sockfd; | |
| 69 | } | |
| 70 | ||
| 71 | void server() | |
| 72 | {
| |
| 73 | int socket = create_socket(true); | |
| 74 | if(listen(socket, 5) == -1) | |
| 75 | {
| |
| 76 | perror("listen");
| |
| 77 | exit(1); | |
| 78 | } | |
| 79 | puts("server: listening");
| |
| 80 | ||
| 81 | int conn = -1; | |
| 82 | sockaddr_storage addr; | |
| 83 | unsigned int sizeof_addr = sizeof(addr); | |
| 84 | ||
| 85 | for(;;) | |
| 86 | {
| |
| 87 | if((conn = accept(socket, (sockaddr *) &addr, &sizeof_addr)) == -1) | |
| 88 | {
| |
| 89 | perror("accept");
| |
| 90 | } | |
| 91 | else | |
| 92 | {
| |
| 93 | puts("server: accept");
| |
| 94 | ||
| 95 | if(!fork()) // actually not necessary, only got 1 client | |
| 96 | {
| |
| 97 | close(socket); | |
| 98 | char *buf = new char[1024*1024]; | |
| 99 | for(;;) read(conn, buf, 1024*1024); // black hole | |
| 100 | } | |
| 101 | } | |
| 102 | } | |
| 103 | } | |
| 104 | ||
| 105 | void do_send(int socket, const char* buf, unsigned int size/*, bool nonblock = false */) | |
| 106 | {
| |
| 107 | unsigned int sent = 0; | |
| 108 | unsigned int count = 0; | |
| 109 | ||
| 110 | while(sent < size) | |
| 111 | {
| |
| 112 | // int n = send(socket, &buf[sent], size - sent, nonblock ? MSG_DONTWAIT : 0); | |
| 113 | int n = send(socket, &buf[sent], size - sent, 0); | |
| 114 | ||
| 115 | if (n == -1) | |
| 116 | {
| |
| 117 | if(errno == EAGAIN) | |
| 118 | {
| |
| 119 | printf(".");
| |
| 120 | } | |
| 121 | else | |
| 122 | {
| |
| 123 | perror("\nsend");
| |
| 124 | return; | |
| 125 | } | |
| 126 | } | |
| 127 | else | |
| 128 | {
| |
| 129 | sent += n; | |
| 130 | printf(" --> sent a chunk of %u bytes (send no. %u, total sent = %u)\n", n, ++count, sent);
| |
| 131 | } | |
| 132 | } | |
| 133 | } | |
| 134 | ||
| 135 | void client() | |
| 136 | {
| |
| 137 | const unsigned int max_size = 64*1024*1024; // sending up to 64MiB in one call | |
| 138 | ||
| 139 | sleep(1); // give server a second to start up | |
| 140 | ||
| 141 | int socket = create_socket(); | |
| 142 | ||
| 143 | ||
| 144 | unsigned int send_buffer_size = 0; | |
| 145 | unsigned int len = sizeof(send_buffer_size); | |
| 146 | ||
| 147 | if(getsockopt(socket, SOL_SOCKET, SO_SNDBUF, &send_buffer_size, &len)) | |
| 148 | perror("getsockopt");
| |
| 149 | ||
| 150 | // Linux internally doubles the buffer size, and getsockopt reports the doubled size | |
| 151 | printf("send buffer size = %u (doubled, actually %u)\n", send_buffer_size, send_buffer_size/2);
| |
| 152 | ||
| 153 | if(socket == -1) | |
| 154 | {
| |
| 155 | puts("no good");
| |
| 156 | exit(1); | |
| 157 | } | |
| 158 | ||
| 159 | char *buf = new char[max_size]; // uninitialized contents, but who cares | |
| 160 | ||
| 161 | for(unsigned int size = 65536; size <= max_size; size += 16384) | |
| 162 | {
| |
| 163 | printf("attempting to send %u bytes\n", size);
| |
| 164 | do_send(socket, buf, size); | |
| 165 | } | |
| 166 | puts("all done");
| |
| 167 | delete buf; | |
| 168 | } | |
| 169 | ||
| 170 | ||
| 171 | int main() | |
| 172 | {
| |
| 173 | if(fork() > 0) server(); else client(); | |
| 174 | return 0; | |
| 175 | } |
