| /* |
| * Sean Middleditch |
| * sean@sourcemud.org |
| * |
| * The author or authors of this code dedicate any and all copyright interest |
| * in this code to the public domain. We make this dedication for the benefit |
| * of the public at large and to the detriment of our heirs and successors. We |
| * intend this dedication to be an overt act of relinquishment in perpetuity of |
| * all present and future rights to this code under copyright law. |
| */ |
| |
| #include <sys/socket.h> |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| #include <netdb.h> |
| #include <poll.h> |
| #include <errno.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <ctype.h> |
| #include <termios.h> |
| #include <unistd.h> |
| |
| #ifdef HAVE_ZLIB |
| #include "zlib.h" |
| #endif |
| |
| #include "libtelnet.h" |
| |
| static struct termios orig_tios; |
| static libtelnet_t telnet; |
| static int do_echo; |
| |
| static void _cleanup(void) { |
| tcsetattr(STDOUT_FILENO, TCSADRAIN, &orig_tios); |
| } |
| |
| static void _input(unsigned char *buffer, int size) { |
| static unsigned char crlf[] = { '\r', '\n' }; |
| int i; |
| |
| for (i = 0; i != size; ++i) { |
| /* if we got a CR or LF, replace with CRLF |
| * NOTE that usually you'd get a CR in UNIX, but in raw |
| * mode we get LF instead (not sure why) |
| */ |
| if (buffer[i] == '\r' || buffer[i] == '\n') { |
| if (do_echo) |
| write(STDOUT_FILENO, crlf, 2); |
| libtelnet_send_data(&telnet, crlf, 2); |
| } else { |
| if (do_echo) |
| write(STDOUT_FILENO, buffer + i, 1); |
| libtelnet_send_data(&telnet, buffer + i, 1); |
| } |
| } |
| } |
| |
| static void _send(int sock, const unsigned char *buffer, unsigned int size) { |
| int rs; |
| |
| /* send data */ |
| while (size > 0) { |
| if ((rs = send(sock, buffer, size, 0)) == -1) { |
| fprintf(stderr, "send() failed: %s\n", strerror(errno)); |
| exit(1); |
| } else if (rs == 0) { |
| fprintf(stderr, "send() unexpectedly returned 0\n"); |
| exit(1); |
| } |
| |
| /* update pointer and size to see if we've got more to send */ |
| buffer += rs; |
| size -= rs; |
| } |
| } |
| |
| static void _event_handler(libtelnet_t *telnet, libtelnet_event_t *ev, |
| void *user_data) { |
| int sock = *(int*)user_data; |
| |
| switch (ev->type) { |
| /* data received */ |
| case LIBTELNET_EV_DATA: |
| write(STDOUT_FILENO, ev->buffer, ev->size); |
| break; |
| /* data must be sent */ |
| case LIBTELNET_EV_SEND: |
| _send(sock, ev->buffer, ev->size); |
| break; |
| /* request to enable remote feature (or receipt) */ |
| case LIBTELNET_EV_WILL: |
| /* we accept COMPRESS2 (MCCP) */ |
| if (ev->telopt == LIBTELNET_TELOPT_COMPRESS2) |
| ev->accept = 1; |
| |
| /* we'll agree to turn off our echo if server wants us to stop */ |
| else if (ev->telopt == LIBTELNET_TELOPT_ECHO) { |
| do_echo = 0; |
| ev->accept = 1; |
| } |
| break; |
| /* notification of disabling remote feature (or receipt) */ |
| case LIBTELNET_EV_WONT: |
| if (ev->telopt == LIBTELNET_TELOPT_ECHO) |
| do_echo = 1; |
| break; |
| /* request to enable local feature (or receipt) */ |
| case LIBTELNET_EV_DO: |
| /* we support the TTYPE option */ |
| if (ev->telopt == LIBTELNET_TELOPT_TTYPE) |
| ev->accept = 1; |
| break; |
| /* demand to disable local feature (or receipt) */ |
| case LIBTELNET_EV_DONT: |
| break; |
| /* respond to particular subnegotiations */ |
| case LIBTELNET_EV_SUBNEGOTIATION: |
| /* respond with our terminal type */ |
| if (ev->telopt == LIBTELNET_TELOPT_TTYPE) { |
| /* NOTE: we just assume the server sent a legitimate |
| * sub-negotiation, as there really isn't anything else |
| * it's allowed to send |
| */ |
| char buffer[64]; |
| buffer[0] = 0; /* IS code for RFC 1091 */ |
| snprintf(buffer + 1, sizeof(buffer) - 1, "%s", getenv("TERM")); |
| libtelnet_send_subnegotiation(telnet, LIBTELNET_TELOPT_TTYPE, |
| (unsigned char *)buffer, 1 + strlen(buffer + 1)); |
| } |
| break; |
| /* error */ |
| case LIBTELNET_EV_ERROR: |
| fprintf(stderr, "ERROR: %.*s\n", ev->size, ev->buffer); |
| exit(1); |
| default: |
| /* ignore */ |
| break; |
| } |
| } |
| |
| int main(int argc, char **argv) { |
| unsigned char buffer[512]; |
| int rs; |
| int sock; |
| struct sockaddr_in addr; |
| struct pollfd pfd[2]; |
| struct addrinfo *ai; |
| struct addrinfo hints; |
| struct termios tios; |
| |
| /* check usage */ |
| if (argc != 3) { |
| fprintf(stderr, "Usage:\n ./telnet-client <host> <port>\n"); |
| return 1; |
| } |
| |
| /* look up server host */ |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_family = AF_UNSPEC; |
| hints.ai_socktype = SOCK_STREAM; |
| if ((rs = getaddrinfo(argv[1], argv[2], &hints, &ai)) != 0) { |
| fprintf(stderr, "getaddrinfo() failed for %s: %s\n", argv[1], |
| gai_strerror(rs)); |
| return 1; |
| } |
| |
| /* create server socket */ |
| if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { |
| fprintf(stderr, "socket() failed: %s\n", strerror(errno)); |
| return 1; |
| } |
| |
| /* bind server socket */ |
| memset(&addr, 0, sizeof(addr)); |
| addr.sin_family = AF_INET; |
| if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) == -1) { |
| fprintf(stderr, "bind() failed: %s\n", strerror(errno)); |
| return 1; |
| } |
| |
| /* connect */ |
| if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { |
| fprintf(stderr, "server() failed: %s\n", strerror(errno)); |
| return 1; |
| } |
| |
| /* free address lookup info */ |
| freeaddrinfo(ai); |
| |
| /* get current terminal settings, set raw mode, make sure we |
| * register atexit handler to restore terminal settings |
| */ |
| tcgetattr(STDOUT_FILENO, &orig_tios); |
| atexit(_cleanup); |
| tios = orig_tios; |
| cfmakeraw(&tios); |
| tcsetattr(STDOUT_FILENO, TCSADRAIN, &tios); |
| |
| /* set input echoing on by default */ |
| do_echo = 1; |
| |
| /* initialize telnet box */ |
| libtelnet_init(&telnet, _event_handler, 0, &sock); |
| |
| /* initialize poll descriptors */ |
| memset(pfd, 0, sizeof(pfd)); |
| pfd[0].fd = STDIN_FILENO; |
| pfd[0].events = POLLIN; |
| pfd[1].fd = sock; |
| pfd[1].events = POLLIN; |
| |
| /* loop while both connections are open */ |
| while (poll(pfd, 2, -1) != -1) { |
| /* read from stdin */ |
| if (pfd[0].revents & POLLIN) { |
| if ((rs = read(STDIN_FILENO, buffer, sizeof(buffer))) > 0) { |
| _input(buffer, rs); |
| } else if (rs == 0) { |
| break; |
| } else { |
| fprintf(stderr, "recv(server) failed: %s\n", |
| strerror(errno)); |
| exit(1); |
| } |
| } |
| |
| /* read from client */ |
| if (pfd[1].revents & POLLIN) { |
| if ((rs = recv(sock, buffer, sizeof(buffer), 0)) > 0) { |
| libtelnet_push(&telnet, buffer, rs); |
| } else if (rs == 0) { |
| break; |
| } else { |
| fprintf(stderr, "recv(client) failed: %s\n", |
| strerror(errno)); |
| exit(1); |
| } |
| } |
| } |
| |
| /* clean up */ |
| libtelnet_free(&telnet); |
| close(sock); |
| |
| return 0; |
| } |