| /* vi: set sw=4 ts=4: */ |
| /* nc: mini-netcat - Forward stdin/stdout to a file or network connection. |
| * |
| * Copyright 2007 Rob Landley <rob@landley.net> |
| * |
| * Not in SUSv3. |
| */ |
| |
| #include "toys.h" |
| #include "toynet.h" |
| |
| #include <sys/socket.h> |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| |
| #define TT toy.netcat |
| |
| static void timeout(int signum) |
| { |
| error_exit("Timeout"); |
| } |
| |
| // Translate x.x.x.x numeric IPv4 address, or else DNS lookup an IPv4 name. |
| void lookup_name(char *name, uint32_t *result) |
| { |
| struct hostent *hostbyname; |
| |
| hostbyname = gethostbyname(*toys.optargs); |
| if (!hostbyname) error_exit("name lookup failed"); |
| *result = *(uint32_t *)*hostbyname->h_addr_list; |
| } |
| |
| // Worry about a fancy lookup later. |
| void lookup_port(char *str, uint16_t *port) |
| { |
| *port = SWAP_BE16(atoi(str)); |
| } |
| |
| void netcat_main(void) |
| { |
| int sockfd, pollcount; |
| struct pollfd pollfds[2]; |
| |
| if (TT.wait) { |
| signal(SIGALRM, timeout); |
| alarm(TT.wait); |
| } |
| |
| if (TT.filename) pollfds[0].fd = xopen(TT.filename, O_RDWR); |
| else { |
| int temp; |
| struct sockaddr_in address; |
| |
| // The argument parsing logic can't make "<2" conditional on "-f", so... |
| if (!*toys.optargs || !toys.optargs[1]) { |
| toys.exithelp++; |
| error_exit("Need address and port"); |
| } |
| |
| // Setup socket |
| sockfd = socket(AF_INET, SOCK_STREAM, 0); |
| if (-1 == sockfd) perror_exit("socket"); |
| fcntl(sockfd, F_SETFD, FD_CLOEXEC); |
| temp = 1; |
| setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &temp, sizeof(temp)); |
| memset(&address, 0, sizeof(address)); |
| address.sin_family = AF_INET; |
| if (TT.port) { |
| address.sin_port = TT.port; |
| if (-1 == bind(sockfd, &address, sizeof(address))) |
| perror_exit("bind"); |
| } |
| |
| // Figure out where to dial out to. |
| lookup_name(*toys.optargs, (uint32_t *)&address.sin_addr); |
| lookup_port(toys.optargs[1], &address.sin_port); |
| temp = connect(sockfd, (struct sockaddr *)&address, sizeof(address)); |
| if (temp<0) perror_exit("connect"); |
| pollfds[0].fd = sockfd; |
| } |
| |
| // We have a connection. Disarm timeout. |
| if (TT.wait) { |
| alarm(0); |
| signal(SIGALRM, SIG_DFL); |
| } |
| |
| pollcount = 2; |
| pollfds[1].fd = 0; |
| pollfds[0].events = pollfds[1].events = POLLIN; |
| |
| // Poll loop copying stdin->socket and socket->stdout. |
| for (;;) { |
| int i; |
| |
| if (0>poll(pollfds, pollcount, -1)) perror_exit("poll"); |
| |
| for (i=0; i<pollcount; i++) { |
| if (pollfds[i].revents & POLLIN) { |
| int len = read(pollfds[i].fd, toybuf, sizeof(toybuf)); |
| if (len<1) goto dohupnow; |
| xwrite(i ? pollfds[0].fd : 1, toybuf, len); |
| } |
| if (pollfds[i].revents & POLLHUP) { |
| dohupnow: |
| // Close half-connect. This is needed for things like |
| // "echo GET / | netcat landley.net 80" to work. |
| if (i) { |
| shutdown(pollfds[0].fd, SHUT_WR); |
| pollcount--; |
| } else goto cleanup; |
| } |
| } |
| } |
| cleanup: |
| close(pollfds[0].fd); |
| // close(sockfd); |
| } |