| /* |
| * 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 <poll.h> |
| #include <errno.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <ctype.h> |
| #include <unistd.h> |
| |
| #ifdef HAVE_ZLIB |
| #include "zlib.h" |
| #endif |
| |
| #include "libtelnet.h" |
| |
| #define MAX_USERS 64 |
| #define LINEBUFFER_SIZE 256 |
| |
| const telnet_telopt_t telopts[] = { |
| { TELNET_TELOPT_COMPRESS2, TELNET_WILL, TELNET_DONT }, |
| { -1, 0, 0 } |
| }; |
| |
| struct user_t { |
| char *name; |
| int sock; |
| telnet_t *telnet; |
| char linebuf[256]; |
| int linepos; |
| }; |
| |
| static struct user_t users[MAX_USERS]; |
| |
| static void linebuffer_push(char *buffer, size_t size, int *linepos, |
| char ch, void (*cb)(const char *line, int overflow, void *ud), |
| void *ud) { |
| |
| /* CRLF -- line terminator */ |
| if (ch == '\n' && *linepos > 0 && buffer[*linepos - 1] == '\r') { |
| /* NUL terminate (replaces \r in buffer), notify app, clear */ |
| buffer[*linepos - 1] = 0; |
| cb(buffer, 0, ud); |
| *linepos = 0; |
| |
| /* CRNUL -- just a CR */ |
| } else if (ch == 0 && *linepos > 0 && buffer[*linepos - 1] == '\r') { |
| /* do nothing, the CR is already in the buffer */ |
| |
| /* anything else (including technically invalid CR followed by |
| * anything besides LF or NUL -- just buffer if we have room |
| * \r |
| */ |
| } else if (*linepos != size) { |
| buffer[(*linepos)++] = ch; |
| |
| /* buffer overflow */ |
| } else { |
| /* terminate (NOTE: eats a byte), notify app, clear buffer */ |
| buffer[size - 1] = 0; |
| cb(buffer, size - 1, ud); |
| *linepos = 0; |
| } |
| } |
| |
| static void _message(const char *from, const char *msg) { |
| int i; |
| for (i = 0; i != MAX_USERS; ++i) { |
| if (users[i].sock != -1) { |
| telnet_printf(users[i].telnet, "%s: %s\n", from, msg); |
| } |
| } |
| } |
| |
| static void _send(int sock, const char *buffer, unsigned int size) { |
| int rs; |
| |
| /* ignore on invalid socket */ |
| if (sock == -1) |
| return; |
| |
| /* send data */ |
| while (size > 0) { |
| if ((rs = send(sock, buffer, size, 0)) == -1) { |
| if (errno != EINTR && errno != ECONNRESET) { |
| fprintf(stderr, "send() failed: %s\n", strerror(errno)); |
| exit(1); |
| } else { |
| return; |
| } |
| } 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; |
| } |
| } |
| |
| /* process input line */ |
| static void _online(const char *line, int overflow, void *ud) { |
| struct user_t *user = (struct user_t*)ud; |
| int i; |
| |
| /* if the user has no name, this is his "login" */ |
| if (user->name == 0) { |
| /* must not be empty, must be at least 32 chars */ |
| if (strlen(line) == 0 || strlen(line) > 32) { |
| telnet_printf(user->telnet, "Invalid name.\nEnter name: "); |
| return; |
| } |
| |
| /* must not already be in use */ |
| for (i = 0; i != MAX_USERS; ++i) { |
| if (users[i].name != 0 && strcmp(users[i].name, line) == 0) { |
| telnet_printf(user->telnet, "Name in use.\nEnter name: "); |
| return; |
| } |
| } |
| |
| /* keep name */ |
| user->name = strdup(line); |
| telnet_printf(user->telnet, "Welcome, %s!\n", line); |
| return; |
| } |
| |
| /* if line is "quit" then, well, quit */ |
| if (strcmp(line, "quit") == 0) { |
| close(user->sock); |
| user->sock = -1; |
| _message(user->name, "** HAS QUIT **"); |
| free(user->name); |
| user->name = 0; |
| return; |
| } |
| |
| /* just a message -- send to all users */ |
| _message(user->name, line); |
| } |
| |
| static void _input(struct user_t *user, const char *buffer, |
| unsigned int size) { |
| unsigned int i; |
| for (i = 0; i != size; ++i) |
| linebuffer_push(user->linebuf, sizeof(user->linebuf), &user->linepos, |
| (char)buffer[i], _online, user); |
| } |
| |
| static void _event_handler(telnet_t *telnet, telnet_event_t *ev, |
| void *user_data) { |
| struct user_t *user = (struct user_t*)user_data; |
| |
| switch (ev->type) { |
| /* data received */ |
| case TELNET_EV_DATA: |
| _input(user, ev->buffer, ev->size); |
| break; |
| /* data must be sent */ |
| case TELNET_EV_SEND: |
| _send(user->sock, ev->buffer, ev->size); |
| break; |
| /* enable compress2 if accepted by client */ |
| case TELNET_EV_DO: |
| if (ev->telopt == TELNET_TELOPT_COMPRESS2) |
| telnet_begin_compress2(telnet); |
| break; |
| /* error */ |
| case TELNET_EV_ERROR: |
| close(user->sock); |
| user->sock = -1; |
| if (user->name != 0) { |
| _message(user->name, "** HAS HAD AN ERROR **"); |
| free(user->name); |
| user->name = 0; |
| } |
| telnet_free(user->telnet); |
| break; |
| default: |
| /* ignore */ |
| break; |
| } |
| } |
| |
| int main(int argc, char **argv) { |
| char buffer[512]; |
| short listen_port; |
| int listen_sock; |
| int rs; |
| int i; |
| struct sockaddr_in addr; |
| socklen_t addrlen; |
| struct pollfd pfd[MAX_USERS + 1]; |
| |
| /* check usage */ |
| if (argc != 2) { |
| fprintf(stderr, "Usage:\n ./telnet-chatd <port>\n"); |
| return 1; |
| } |
| |
| /* initialize data structures */ |
| memset(&pfd, 0, sizeof(pfd)); |
| memset(users, 0, sizeof(users)); |
| for (i = 0; i != MAX_USERS; ++i) |
| users[i].sock = -1; |
| |
| /* parse listening port */ |
| listen_port = strtol(argv[1], 0, 10); |
| |
| /* create listening socket */ |
| if ((listen_sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { |
| fprintf(stderr, "socket() failed: %s\n", strerror(errno)); |
| return 1; |
| } |
| |
| /* reuse address option */ |
| rs = 1; |
| setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, &rs, sizeof(rs)); |
| |
| /* bind to listening addr/port */ |
| memset(&addr, 0, sizeof(addr)); |
| addr.sin_family = AF_INET; |
| addr.sin_addr.s_addr = INADDR_ANY; |
| addr.sin_port = htons(listen_port); |
| if (bind(listen_sock, (struct sockaddr *)&addr, sizeof(addr)) == -1) { |
| fprintf(stderr, "bind() failed: %s\n", strerror(errno)); |
| return 1; |
| } |
| |
| /* listen for clients */ |
| if (listen(listen_sock, 5) == -1) { |
| fprintf(stderr, "listen() failed: %s\n", strerror(errno)); |
| return 1; |
| } |
| |
| printf("LISTENING ON PORT %d\n", listen_port); |
| |
| /* initialize listening descriptors */ |
| pfd[MAX_USERS].fd = listen_sock; |
| pfd[MAX_USERS].events = POLLIN; |
| |
| /* loop for ever */ |
| for (;;) { |
| /* prepare for poll */ |
| for (i = 0; i != MAX_USERS; ++i) { |
| if (users[i].sock != -1) { |
| pfd[i].fd = users[i].sock; |
| pfd[i].events = POLLIN; |
| } else { |
| pfd[i].fd = -1; |
| pfd[i].events = 0; |
| } |
| } |
| |
| /* poll */ |
| rs = poll(pfd, MAX_USERS + 1, -1); |
| if (rs == -1 && errno != EINTR) { |
| fprintf(stderr, "poll() failed: %s\n", strerror(errno)); |
| return 1; |
| } |
| |
| /* new connection */ |
| if (pfd[MAX_USERS].revents & POLLIN) { |
| /* acept the sock */ |
| addrlen = sizeof(addr); |
| if ((rs = accept(listen_sock, (struct sockaddr *)&addr, |
| &addrlen)) == -1) { |
| fprintf(stderr, "accept() failed: %s\n", strerror(errno)); |
| return 1; |
| } |
| |
| printf("Connection received.\n"); |
| |
| /* find a free user */ |
| for (i = 0; i != MAX_USERS; ++i) |
| if (users[i].sock == -1) |
| break; |
| if (i == MAX_USERS) { |
| printf(" rejected (too many users)\n"); |
| _send(rs, "Too many users.\r\n", 14); |
| close(rs); |
| } |
| |
| /* init, welcome */ |
| users[i].sock = rs; |
| users[i].telnet = telnet_init(telopts, _event_handler, 0, |
| &users[i]); |
| telnet_negotiate(users[i].telnet, TELNET_WILL, |
| TELNET_TELOPT_COMPRESS2); |
| telnet_printf(users[i].telnet, "Enter name: "); |
| } |
| |
| /* read from client */ |
| for (i = 0; i != MAX_USERS; ++i) { |
| /* skip users that aren't actually connected */ |
| if (users[i].sock == -1) |
| continue; |
| |
| if (pfd[i].revents & POLLIN) { |
| if ((rs = recv(users[i].sock, buffer, sizeof(buffer), 0)) > 0) { |
| telnet_recv(users[i].telnet, buffer, rs); |
| } else if (rs == 0) { |
| printf("Connection closed.\n"); |
| close(users[i].sock); |
| if (users[i].name != 0) { |
| _message(users[i].name, "** HAS DISCONNECTED **"); |
| free(users[i].name); |
| users[i].name = 0; |
| } |
| telnet_free(users[i].telnet); |
| users[i].sock = -1; |
| break; |
| } else if (errno != EINTR) { |
| fprintf(stderr, "recv(client) failed: %s\n", |
| strerror(errno)); |
| exit(1); |
| } |
| } |
| } |
| } |
| |
| /* not that we can reach this, but GCC will cry if it's not here */ |
| return 0; |
| } |