diff options
Diffstat (limited to 'relay.c')
| -rw-r--r-- | relay.c | 227 |
1 files changed, 227 insertions, 0 deletions
@@ -0,0 +1,227 @@ +/* + * Sample program to be used as a transparent proxy. + * + * Must be executed with permission enough to do an ioctl on /dev/ipl + * or equivalent. This is just a sample and is only alpha quality. + * - Darren Reed (8 April 1996) + */ +#include <unistd.h> +#include <stdio.h> +#include <fcntl.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/errno.h> +#include <sys/syslog.h> +#include <sys/ioctl.h> +#include <netinet/in.h> +#include <net/if.h> +#include <sys/socket.h> +#if defined(__NetBSD_Version__) && (__NetBSD_Version__ >= 105000000) +# include <poll.h> +# define USE_POLL +#endif +#include "ip_nat.h" + +#define RELAY_BUFSZ 8192 + +char ibuff[RELAY_BUFSZ]; +char obuff[RELAY_BUFSZ]; + +int relay(ifd, ofd, rfd) +int ifd, ofd, rfd; +{ +#ifdef USE_POLL + struct pollfd set[3]; +#else + fd_set rfds, wfds; +#endif + char *irh, *irt, *rrh, *rrt; + char *iwh, *iwt, *rwh, *rwt; + int nfd, n, rw; + + irh = irt = ibuff; + iwh = iwt = obuff; + nfd = ifd; + if (nfd < ofd) + nfd = ofd; + if (nfd < rfd) + nfd = rfd; + +#ifdef USE_POLL + set[0].fd = rfd; + set[1].fd = ifd; + set[2].fd = ofd; +#endif + + while (1) { +#ifdef USE_POLL + set[0].events = (iwh < (obuff + RELAY_BUFSZ) ? POLLIN : 0) | + (irh > irt ? POLLOUT : 0); + set[1].events = (irh < (ibuff + RELAY_BUFSZ) ? POLLIN : 0); + set[2].events = (iwh > iwt ? POLLOUT : 0); + + switch ((n = poll(set, 3, INFTIM))) +#else + FD_ZERO(&rfds); + FD_ZERO(&wfds); + if (irh > irt) + FD_SET(rfd, &wfds); + if (irh < (ibuff + RELAY_BUFSZ)) + FD_SET(ifd, &rfds); + if (iwh > iwt) + FD_SET(ofd, &wfds); + if (iwh < (obuff + RELAY_BUFSZ)) + FD_SET(rfd, &rfds); + + switch ((n = select(nfd + 1, &rfds, &wfds, NULL, NULL))) +#endif + { + case -1 : + case 0 : + return -1; + default : +#ifdef USE_POLL + if (set[1].revents & POLLIN) +#else + if (FD_ISSET(ifd, &rfds)) +#endif + { + rw = read(ifd, irh, ibuff + RELAY_BUFSZ - irh); + if (rw == -1) + return -1; + if (rw == 0) + return 0; + irh += rw; + n--; + } +#ifdef USE_POLL + if (set[2].revents & POLLOUT) +#else + if (n && FD_ISSET(ofd, &wfds)) +#endif + { + rw = write(ofd, iwt, iwh - iwt); + if (rw == -1) + return -1; + iwt += rw; + n--; + } +#ifdef USE_POLL + if (set[0].revents & POLLIN) +#else + if (n && FD_ISSET(rfd, &rfds)) +#endif + { + rw = read(rfd, iwh, obuff + RELAY_BUFSZ - iwh); + if (rw == -1) + return -1; + if (rw == 0) + return 0; + iwh += rw; + n--; + } +#ifdef USE_POLL + if (set[0].revents & POLLOUT) +#else + if (n && FD_ISSET(rfd, &wfds)) +#endif + { + rw = write(rfd, irt, irh - irt); + if (rw == -1) + return -1; + irt += rw; + n--; + } + if (irh == irt) + irh = irt = ibuff; + if (iwh == iwt) + iwh = iwt = obuff; + } + } +} + +main(argc, argv) +int argc; +char *argv[]; +{ + struct sockaddr_in sin; + natlookup_t nl; + natlookup_t *nlp = &nl; + int fd, sl = sizeof(sl), se; + + openlog(argv[0], LOG_PID|LOG_NDELAY, LOG_DAEMON); + if ((fd = open("/dev/ipnat", O_RDONLY)) == -1) { + se = errno; + perror("open"); + errno = se; + syslog(LOG_ERR, "open: %m\n"); + exit(-1); + } + + bzero(&nl, sizeof(nl)); + nl.nl_flags = IPN_TCP; + + bzero(&sin, sizeof(sin)); + sin.sin_family = AF_INET; + sl = sizeof(sin); + if (getsockname(0, (struct sockaddr *)&sin, &sl) == -1) { + se = errno; + perror("getsockname"); + errno = se; + syslog(LOG_ERR, "getsockname: %m\n"); + exit(-1); + } else { + nl.nl_inip.s_addr = sin.sin_addr.s_addr; + nl.nl_inport = sin.sin_port; + } + + bzero(&sin, sizeof(sin)); + sin.sin_family = AF_INET; + sl = sizeof(sin); + if (getpeername(0, (struct sockaddr *)&sin, &sl) == -1) { + se = errno; + perror("getpeername"); + errno = se; + syslog(LOG_ERR, "getpeername: %m\n"); + exit(-1); + } else { + nl.nl_outip.s_addr = sin.sin_addr.s_addr; + nl.nl_outport = sin.sin_port; + } + + if (ioctl(fd, SIOCGNATL, &nlp) == -1) { + se = errno; + perror("ioctl"); + errno = se; + syslog(LOG_ERR, "ioctl: %m\n"); + exit(-1); + } + + sin.sin_port = nl.nl_realport; + sin.sin_addr = nl.nl_realip; + sl = sizeof(sin); + + fd = socket(AF_INET, SOCK_STREAM, 0); + if (connect(fd, (struct sockaddr *)&sin, sl) == -1) { + se = errno; + perror("connect"); + errno = se; + syslog(LOG_ERR, "connect: %m\n"); + exit(-1); + } + + (void) ioctl(fd, F_SETFL, ioctl(fd, F_GETFL, 0)|O_NONBLOCK); + (void) ioctl(0, F_SETFL, ioctl(fd, F_GETFL, 0)|O_NONBLOCK); + (void) ioctl(1, F_SETFL, ioctl(fd, F_GETFL, 0)|O_NONBLOCK); + + syslog(LOG_NOTICE, "connected to %s,%d\n", inet_ntoa(sin.sin_addr), + ntohs(sin.sin_port)); + if (relay(0, 1, fd) == -1) { + se = errno; + perror("relay"); + errno = se; + syslog(LOG_ERR, "relay: %m\n"); + exit(-1); + } + exit(0); +} |
