/* $NetBSD: relay.c,v 1.1.1.1 2012/03/23 21:20:15 christos Exp $ */ /* * 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 #include #include #include #include #include #include #include #include #include #include #include "netinet/ip_compat.h" #include "netinet/ip_fil.h" #include "netinet/ip_nat.h" #include "netinet/ipl.h" #define RELAY_BUFSZ 8192 char ibuff[RELAY_BUFSZ]; char obuff[RELAY_BUFSZ]; int relay(ifd, ofd, rfd) int ifd, ofd, rfd; { fd_set rfds, wfds; 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; while (1) { 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))) { case -1 : case 0 : return -1; default : if (FD_ISSET(ifd, &rfds)) { rw = read(ifd, irh, ibuff + RELAY_BUFSZ - irh); if (rw == -1) return -1; if (rw == 0) return 0; irh += rw; n--; } if (n && FD_ISSET(ofd, &wfds)) { rw = write(ofd, iwt, iwh - iwt); if (rw == -1) return -1; iwt += rw; n--; } if (n && FD_ISSET(rfd, &rfds)) { rw = read(rfd, iwh, obuff + RELAY_BUFSZ - iwh); if (rw == -1) return -1; if (rw == 0) return 0; iwh += rw; n--; } if (n && FD_ISSET(rfd, &wfds)) { 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; ipfobj_t obj; 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(IPNAT_NAME, O_RDONLY)) == -1) { se = errno; perror("open"); errno = se; syslog(LOG_ERR, "open: %m\n"); exit(-1); } bzero(&obj, sizeof(obj)); obj.ipfo_rev = IPFILTER_VERSION; obj.ipfo_size = sizeof(nl); obj.ipfo_ptr = &nl; obj.ipfo_type = IPFOBJ_NATLOOKUP; 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, &obj) == -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); }