Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 1 | #include <sys/socket.h> |
| 2 | #include <netinet/in.h> |
| 3 | #include <arpa/inet.h> |
| 4 | #include <poll.h> |
| 5 | #include <errno.h> |
| 6 | #include <stdio.h> |
| 7 | #include <string.h> |
| 8 | #include <stdlib.h> |
| 9 | #include <ctype.h> |
| 10 | #include <unistd.h> |
| 11 | |
| 12 | #include "libtelnet.h" |
| 13 | |
| 14 | static int server_sock; |
| 15 | static int client_sock; |
| 16 | |
| 17 | static struct libtelnet_t server_telnet; |
| 18 | static struct libtelnet_t client_telnet; |
| 19 | |
Sean Middleditch | 0f91258 | 2009-03-14 01:57:07 -0400 | [diff] [blame^] | 20 | static const char *get_name(int sock) { |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 21 | if (sock == server_sock) |
| 22 | return "\e[31mSERVER"; |
| 23 | else |
| 24 | return "\e[34mCLIENT"; |
| 25 | } |
| 26 | |
Sean Middleditch | 0f91258 | 2009-03-14 01:57:07 -0400 | [diff] [blame^] | 27 | static const char *get_cmd(unsigned char cmd) { |
| 28 | static char buffer[4]; |
| 29 | |
| 30 | switch (cmd) { |
| 31 | case 255: return "IAC"; |
| 32 | case 254: return "DONT"; |
| 33 | case 253: return "DO"; |
| 34 | case 252: return "WONT"; |
| 35 | case 251: return "WILL"; |
| 36 | case 250: return "SB"; |
| 37 | case 249: return "GA"; |
| 38 | case 248: return "EL"; |
| 39 | case 247: return "EC"; |
| 40 | case 246: return "AYT"; |
| 41 | case 245: return "AO"; |
| 42 | case 244: return "IP"; |
| 43 | case 243: return "BREAK"; |
| 44 | case 242: return "DM"; |
| 45 | case 241: return "NOP"; |
| 46 | case 240: return "SE"; |
| 47 | case 239: return "EOR"; |
| 48 | case 238: return "ABORT"; |
| 49 | case 237: return "SUSP"; |
| 50 | case 236: return "xEOF"; |
| 51 | default: |
| 52 | snprintf(buffer, sizeof(buffer), "%d", (int)cmd); |
| 53 | return buffer; |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | static const char *get_opt(unsigned char opt) { |
| 58 | switch (opt) { |
| 59 | case 0: return "BINARY"; |
| 60 | case 1: return "ECHO"; |
| 61 | case 2: return "RCP"; |
| 62 | case 3: return "SGA"; |
| 63 | case 4: return "NAMS"; |
| 64 | case 5: return "STATUS"; |
| 65 | case 6: return "TM"; |
| 66 | case 7: return "RCTE"; |
| 67 | case 8: return "NAOL"; |
| 68 | case 9: return "NAOP"; |
| 69 | case 10: return "NAOCRD"; |
| 70 | case 11: return "NAOHTS"; |
| 71 | case 12: return "NAOHTD"; |
| 72 | case 13: return "NAOFFD"; |
| 73 | case 14: return "NAOVTS"; |
| 74 | case 15: return "NAOVTD"; |
| 75 | case 16: return "NAOLFD"; |
| 76 | case 17: return "XASCII"; |
| 77 | case 18: return "LOGOUT"; |
| 78 | case 19: return "BM"; |
| 79 | case 20: return "DET"; |
| 80 | case 21: return "SUPDUP"; |
| 81 | case 22: return "SUPDUPOUTPUT"; |
| 82 | case 23: return "SNDLOC"; |
| 83 | case 24: return "TTYPE"; |
| 84 | case 25: return "EOR"; |
| 85 | case 26: return "TUID"; |
| 86 | case 27: return "OUTMRK"; |
| 87 | case 28: return "TTYLOC"; |
| 88 | case 29: return "3270REGIME"; |
| 89 | case 30: return "X3PAD"; |
| 90 | case 31: return "NAWS"; |
| 91 | case 32: return "TSPEED"; |
| 92 | case 33: return "LFLOW"; |
| 93 | case 34: return "LINEMODE"; |
| 94 | case 35: return "XDISPLOC"; |
| 95 | case 36: return "ENVIRON"; |
| 96 | case 37: return "AUTHENTICATION"; |
| 97 | case 38: return "ENCRYPT"; |
| 98 | case 39: return "NEW-ENVIRON"; |
| 99 | case 70: return "MSSP"; |
| 100 | case 85: return "COMPRESS"; |
| 101 | case 86: return "COMPRESS2"; |
| 102 | case 93: return "ZMP"; |
| 103 | case 255: return "EXOPL"; |
| 104 | default: return "unknown"; |
| 105 | } |
| 106 | } |
| 107 | |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 108 | static struct libtelnet_t *other_telnet(struct libtelnet_t *telnet) { |
| 109 | if (telnet == &server_telnet) |
| 110 | return &client_telnet; |
| 111 | else |
| 112 | return &server_telnet; |
| 113 | } |
| 114 | |
| 115 | static void* other_socket(int sock) { |
| 116 | if (sock == server_sock) |
| 117 | return (void*)&client_sock; |
| 118 | else |
| 119 | return (void*)&server_sock; |
| 120 | } |
| 121 | |
| 122 | static void print_buffer(unsigned char *buffer, unsigned int size) { |
| 123 | unsigned int i; |
| 124 | for (i = 0; i != size; ++i) { |
| 125 | if (buffer[i] == ' ' || (isprint(buffer[i]) && !isspace(buffer[i]))) |
| 126 | printf("%c", (char)buffer[i]); |
| 127 | else if (buffer[i] == '\n') |
| 128 | printf("<%02X>\n", (int)buffer[i]); |
| 129 | else |
| 130 | printf("<%02X>", (int)buffer[i]); |
| 131 | } |
| 132 | } |
| 133 | |
Sean Middleditch | 78f400f | 2009-03-14 01:26:43 -0400 | [diff] [blame] | 134 | void libtelnet_data_cb(struct libtelnet_t *telnet, unsigned char *buffer, |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 135 | unsigned int size, void *user_data) { |
| 136 | int sock = *(int*)user_data; |
| 137 | |
Sean Middleditch | 78f400f | 2009-03-14 01:26:43 -0400 | [diff] [blame] | 138 | printf("%s DATA: ", get_name(sock)); |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 139 | print_buffer(buffer, size); |
| 140 | printf("\e[0m\n"); |
| 141 | |
| 142 | libtelnet_send_data(other_telnet(telnet), buffer, size, |
| 143 | other_socket(sock)); |
| 144 | } |
| 145 | |
Sean Middleditch | 78f400f | 2009-03-14 01:26:43 -0400 | [diff] [blame] | 146 | void libtelnet_send_cb(struct libtelnet_t *telnet, unsigned char *buffer, |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 147 | unsigned int size, void *user_data) { |
| 148 | int sock = *(int*)user_data; |
| 149 | |
| 150 | /* DONT SPAM |
Sean Middleditch | 78f400f | 2009-03-14 01:26:43 -0400 | [diff] [blame] | 151 | printf("%s SEND: ", get_name(sock)); |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 152 | print_buffer(buffer, size); |
| 153 | printf("\e[0m\n"); |
| 154 | */ |
| 155 | |
| 156 | /* send data */ |
| 157 | send(sock, buffer, size, 0); |
| 158 | } |
| 159 | |
| 160 | void libtelnet_command_cb(struct libtelnet_t *telnet, unsigned char cmd, |
| 161 | void *user_data) { |
| 162 | int sock = *(int*)user_data; |
| 163 | |
Sean Middleditch | 0f91258 | 2009-03-14 01:57:07 -0400 | [diff] [blame^] | 164 | printf("%s IAC %s\e[0m\n", get_name(sock), get_cmd(cmd)); |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 165 | |
| 166 | libtelnet_send_command(other_telnet(telnet), cmd, other_socket(sock)); |
| 167 | } |
| 168 | |
| 169 | void libtelnet_negotiate_cb(struct libtelnet_t *telnet, unsigned char cmd, |
| 170 | unsigned char opt, void *user_data) { |
| 171 | int sock = *(int*)user_data; |
| 172 | |
Sean Middleditch | 0f91258 | 2009-03-14 01:57:07 -0400 | [diff] [blame^] | 173 | printf("%s IAC %s %d (%s)\e[0m\n", get_name(sock), get_cmd(cmd), |
| 174 | (int)opt, get_opt(opt)); |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 175 | |
| 176 | libtelnet_send_negotiate(other_telnet(telnet), cmd, opt, |
| 177 | other_socket(sock)); |
| 178 | } |
| 179 | |
| 180 | void libtelnet_subrequest_cb(struct libtelnet_t *telnet, unsigned char type, |
| 181 | unsigned char *buffer, unsigned int size, void *user_data) { |
| 182 | int sock = *(int*)user_data; |
| 183 | |
Sean Middleditch | 0f91258 | 2009-03-14 01:57:07 -0400 | [diff] [blame^] | 184 | printf("%s SUB %d (%s)", get_name(sock), (int)type, get_opt(type)); |
| 185 | if (size > 0) { |
| 186 | printf(": "); |
| 187 | print_buffer(buffer, size); |
| 188 | } |
Sean Middleditch | b9ab0b6 | 2009-03-14 00:18:44 -0400 | [diff] [blame] | 189 | printf("\e[0m\n"); |
| 190 | |
| 191 | libtelnet_send_subrequest(other_telnet(telnet), type, buffer, size, |
| 192 | other_socket(sock)); |
| 193 | } |
| 194 | |
| 195 | void libtelnet_error_cb(struct libtelnet_t *telnet, |
| 196 | enum libtelnet_error_t error, void *user_data) { |
| 197 | int sock = *(int*)user_data; |
| 198 | |
| 199 | printf("%s ERROR: %d\e[0m\n", get_name(sock), (int)error); |
| 200 | } |
| 201 | |
| 202 | int main(int argc, char **argv) { |
| 203 | unsigned char buffer[512]; |
| 204 | int listen_sock; |
| 205 | int rs; |
| 206 | struct sockaddr_in addr; |
| 207 | socklen_t addrlen; |
| 208 | struct pollfd pfd[2]; |
| 209 | |
| 210 | /* check usage */ |
| 211 | if (argc != 4) { |
| 212 | fprintf(stderr, "Usage:\n ./telnet-proxy <remote ip> <remote port> <local port>\n"); |
| 213 | return 1; |
| 214 | } |
| 215 | |
| 216 | /* create listening socket */ |
| 217 | if ((listen_sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { |
| 218 | fprintf(stderr, "socket() failed: %s\n", strerror(errno)); |
| 219 | return 1; |
| 220 | } |
| 221 | |
| 222 | /* re-use addr */ |
| 223 | rs = 1; |
| 224 | setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, &rs, sizeof(rs)); |
| 225 | |
| 226 | /* bind */ |
| 227 | memset(&addr, 0, sizeof(addr)); |
| 228 | addr.sin_family = AF_INET; |
| 229 | addr.sin_addr.s_addr = INADDR_ANY; |
| 230 | addr.sin_port = htons(strtol(argv[3], 0, 10)); |
| 231 | if (bind(listen_sock, (struct sockaddr *)&addr, sizeof(addr)) == -1) { |
| 232 | fprintf(stderr, "bind() failed: %s\n", strerror(errno)); |
| 233 | return 1; |
| 234 | } |
| 235 | |
| 236 | /* listen */ |
| 237 | if (listen(listen_sock, 5) == -1) { |
| 238 | fprintf(stderr, "listen() failed: %s\n", strerror(errno)); |
| 239 | return 1; |
| 240 | } |
| 241 | |
| 242 | /* wait for client connection */ |
| 243 | if ((client_sock = accept(listen_sock, (struct sockaddr *)&addr, &addrlen)) == -1) { |
| 244 | fprintf(stderr, "accept() failed: %s\n", strerror(errno)); |
| 245 | return 1; |
| 246 | } |
| 247 | |
| 248 | /* create server socket */ |
| 249 | if ((server_sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { |
| 250 | fprintf(stderr, "socket() failed: %s\n", strerror(errno)); |
| 251 | return 1; |
| 252 | } |
| 253 | |
| 254 | /* bind */ |
| 255 | memset(&addr, 0, sizeof(addr)); |
| 256 | addr.sin_family = AF_INET; |
| 257 | if (bind(server_sock, (struct sockaddr *)&addr, sizeof(addr)) == -1) { |
| 258 | fprintf(stderr, "bind() failed: %s\n", strerror(errno)); |
| 259 | return 1; |
| 260 | } |
| 261 | |
| 262 | /* connect */ |
| 263 | memset(&addr, 0, sizeof(addr)); |
| 264 | if (inet_pton(AF_INET, argv[1], &addr.sin_addr) != 1) { |
| 265 | fprintf(stderr, "inet_pton() failed: %s\n", strerror(errno)); |
| 266 | return 1; |
| 267 | } |
| 268 | addr.sin_family = AF_INET; |
| 269 | addr.sin_port = htons(strtol(argv[2], 0, 10)); |
| 270 | if (connect(server_sock, (struct sockaddr *)&addr, sizeof(addr)) == -1) { |
| 271 | fprintf(stderr, "server() failed: %s\n", strerror(errno)); |
| 272 | return 1; |
| 273 | } |
| 274 | |
| 275 | /* initialize telnet boxes */ |
| 276 | libtelnet_init(&server_telnet); |
| 277 | libtelnet_init(&client_telnet); |
| 278 | |
| 279 | /* initialize poll descriptors */ |
| 280 | memset(pfd, 0, sizeof(pfd)); |
| 281 | pfd[0].fd = server_sock; |
| 282 | pfd[0].events = POLLIN | POLLHUP; |
| 283 | pfd[1].fd = client_sock; |
| 284 | pfd[1].events = POLLIN | POLLHUP; |
| 285 | |
| 286 | /* loop while both connections are open */ |
| 287 | while (poll(pfd, 2, -1) != -1) { |
| 288 | /* read from server */ |
| 289 | if (pfd[0].revents & POLLIN) { |
| 290 | if ((rs = recv(pfd[0].fd, buffer, sizeof(buffer), 0)) > 0) |
| 291 | libtelnet_push(&server_telnet, buffer, rs, (void*)&pfd[0].fd); |
| 292 | } |
| 293 | if (pfd[0].revents & POLLHUP) |
| 294 | break; |
| 295 | |
| 296 | /* read from client */ |
| 297 | if (pfd[1].revents & POLLIN) { |
| 298 | if ((rs = recv(pfd[1].fd, buffer, sizeof(buffer), 0)) > 0) |
| 299 | libtelnet_push(&client_telnet, buffer, rs, (void*)&pfd[1].fd); |
| 300 | } |
| 301 | if (pfd[1].revents & POLLHUP) |
| 302 | break; |
| 303 | } |
| 304 | |
| 305 | /* clean up */ |
| 306 | libtelnet_free(&server_telnet); |
| 307 | libtelnet_free(&client_telnet); |
| 308 | close(server_sock); |
| 309 | close(client_sock); |
| 310 | close(listen_sock); |
| 311 | |
| 312 | return 0; |
| 313 | } |