/* * Copyright (c) 2001, Adam Dunkels. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote * products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * This file is part of the uIP TCP/IP stack. * * $Id: tunslip.c,v 1.4 2006/09/26 15:45:09 bg- Exp $ * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int ssystem(const char *fmt, ...) __attribute__((__format__ (__printf__, 1, 2))); void write_to_serial(int outfd, void *inbuf, int len); //#define PROGRESS(s) fprintf(stderr, s) #define PROGRESS(s) do { } while (0) struct ip { u_int8_t ip_vhl; /* version and header length */ #define IP_V4 0x40 #define IP_V 0xf0 #define IP_HL 0x0f u_int8_t ip_tos; /* type of service */ u_int16_t ip_len; /* total length */ u_int16_t ip_id; /* identification */ u_int16_t ip_off; /* fragment offset field */ #define IP_RF 0x8000 /* reserved fragment flag */ #define IP_DF 0x4000 /* dont fragment flag */ #define IP_MF 0x2000 /* more fragments flag */ #define IP_OFFMASK 0x1fff /* mask for fragmenting bits */ u_int8_t ip_ttl; /* time to live */ u_int8_t ip_p; /* protocol */ u_int16_t ip_sum; /* checksum */ u_int32_t ip_src, ip_dst; /* source and dest address */ u_int16_t uh_sport; /* source port */ u_int16_t uh_dport; /* destination port */ u_int16_t uh_ulen; /* udp length */ u_int16_t uh_sum; /* udp checksum */ }; int check_ip(const struct ip *ip, unsigned ip_len); u_int16_t ip4sum(u_int16_t sum, const void *_p, u_int16_t len); struct dhcp_msg { u_int8_t op, htype, hlen, hops; u_int8_t xid[4]; u_int16_t secs, flags; u_int8_t ciaddr[4]; u_int8_t yiaddr[4]; u_int8_t siaddr[4]; u_int8_t giaddr[4]; u_int8_t chaddr[16]; #define DHCP_BASE_LEN (4*7 + 16) u_int8_t sname[64]; u_int8_t file[128]; #define DHCP_HOLE_LEN (64 + 128) #define DHCP_MSG_LEN (DHCP_BASE_LEN + DHCP_HOLE_LEN) u_int8_t options[312]; }; struct dhcp_light_msg { u_int8_t op, htype, hlen, hops; u_int8_t xid[4]; u_int16_t secs, flags; u_int8_t ciaddr[4]; u_int8_t yiaddr[4]; u_int8_t siaddr[4]; u_int8_t giaddr[4]; u_int8_t chaddr[16]; #define DHCP_LIGHT_MSG_LEN (4*7 + 16) u_int8_t options[312]; }; #define DHCP_OPTION_SUBNET_MASK 1 #define DHCP_OPTION_ROUTER 3 #define DHCP_OPTION_DNS_SERVER 6 #define DHCP_OPTION_REQ_IPADDR 50 #define DHCP_OPTION_LEASE_TIME 51 #define DHCP_OPTION_MSG_TYPE 53 #define DHCP_OPTION_SERVER_ID 54 #define DHCP_OPTION_REQ_LIST 55 #define DHCP_OPTION_AGENT 82 #define DHCP_OPTION_SUBNET_SELECTION 118 #define DHCP_OPTION_END 255 /* DHCP_OPTION_AGENT, Relay Agent Information option subtypes: */ #define RAI_CIRCUIT_ID 1 #define RAI_REMOTE_ID 2 #define RAI_AGENT_ID 3 #define RAI_SUBNET_SELECTION 5 #define DHCPDISCOVER 1 #define DHCPOFFER 2 #define DHCPREQUEST 3 #define DHCPDECLINE 4 #define DHCPACK 5 #define DHCPNAK 6 #define DHCPRELEASE 7 #define BOOTP_BROADCAST 0x8000 #define BOOTPS 67 #define BOOTPC 68 #define BOOTREQUEST 1 #define BOOTREPLY 2 in_addr_t giaddr; in_addr_t netaddr; in_addr_t circuit_addr; char tundev[32] = { "tun0" }; struct sockaddr_in dhaddr; int dhsock = -1; void relay_dhcp_to_server(struct ip *ip, int len) { struct dhcp_light_msg *inm; struct dhcp_msg m; int n; u_int8_t *optptr; inm = (void*)(((u_int8_t*)ip) + 20 + 8); /* Skip over IP&UDP headers. */ if (inm->op != BOOTREQUEST) { return; } inm->flags = ntohs(BOOTP_BROADCAST); memcpy(&m, inm, DHCP_BASE_LEN); memset(&m.sname, 0x0, DHCP_HOLE_LEN); memcpy(&m.options, &inm->options, len - 20 - 8 - DHCP_BASE_LEN); n = (len - 20 - 8) + DHCP_HOLE_LEN; /* +HOLE -IP&UDP headers. */ /* * Ideally we would like to use the Relay Agent information option * (RFC3046) together with the Link Selection sub-option (RFC3527) * to ensure that addresses are allocated for this * subnet. Unfortunately ISC-DHCPD does not currently implement * RFC3527 and some other mechanism must be used. For this reason * this implementation in addition uses the DHCP option for subnet * selection (RFC3011) which is really not intended to be used by * relays. * * Find DHCP_OPTION_END and add the new option here. */ optptr = &m.options[n - DHCP_BASE_LEN - DHCP_HOLE_LEN - 1]; { *optptr++ = DHCP_OPTION_SUBNET_SELECTION; /* RFC3011 */ *optptr++ = 4; memcpy(optptr, &netaddr, 4); optptr += 4; n += 4 + 2; } { *optptr++ = DHCP_OPTION_AGENT; /* RFC3046 */ *optptr++ = 18; /* Sum of all suboptions below! */ *optptr++ = RAI_SUBNET_SELECTION; /* RFC3527 */ *optptr++ = 4; memcpy(optptr, &netaddr, 4); optptr += 4; *optptr++ = RAI_CIRCUIT_ID; *optptr++ = 4; memcpy(optptr, &circuit_addr, 4); optptr += 4; *optptr++ = RAI_AGENT_ID; *optptr++ = 4; memcpy(optptr, &giaddr, 4); optptr += 4; n += 18 + 2; /* Sum of all suboptions + 2! */ } /* And finally put back the END. */ *optptr++ = DHCP_OPTION_END; m.hops++; memcpy(m.giaddr, &giaddr, sizeof(m.giaddr)); if (n != sendto(dhsock, &m, n, 0x0/*flags*/, (struct sockaddr *)&dhaddr, sizeof(dhaddr))) err(1, "sendto relay failed"); } static u_int16_t ip_id; void relay_dhcp_to_client(int slipfd) { struct dhcp_msg inm; struct { struct ip ip; struct dhcp_light_msg m; } pkt; int n, optlen, ip_len, udp_len; u_int8_t *p, *t, *end; u_int16_t sum; u_int8_t op, msg_type = 0; struct in_addr yiaddr; memset(&inm.options, 0x0, sizeof(inm.options)); n = recv(dhsock, &inm, sizeof(inm), 0x0/*flags*/); if (inm.op != BOOTREPLY) { return; } memcpy(&yiaddr, inm.yiaddr, sizeof(inm.yiaddr)); memcpy(&pkt.m, &inm, DHCP_BASE_LEN); pkt.m.hops++; memset(pkt.m.giaddr, 0x0, sizeof(pkt.m.giaddr)); /* * Copy options we would like to send to client. */ memcpy(pkt.m.options, inm.options, 4); /* Magic cookie */ end = &inm.op + n; p = inm.options + 4; /* Magic cookie */ t = pkt.m.options + 4; /* Magic cookie */ while (p < end) { op = p[0]; switch (op) { case DHCP_OPTION_END: goto done; case DHCP_OPTION_MSG_TYPE: msg_type = p[2]; case DHCP_OPTION_SUBNET_MASK: case DHCP_OPTION_ROUTER: case DHCP_OPTION_LEASE_TIME: case DHCP_OPTION_SERVER_ID: /* Copy these options */ memcpy(t, p, p[1] + 2); t += p[1] + 2; p += p[1] + 2; break; case DHCP_OPTION_DNS_SERVER: /* Only copy first server */ memcpy(t, p, 4/**/ + 2); t += 4/**/ + 2; p += p[1] + 2; break; default: /* Ignore these options */ /* printf("option type %d len %d\n", op, p[1]); */ p += p[1] + 2; continue; } } done: if (op == DHCP_OPTION_END) { *t++ = op; *p++; } optlen = t - pkt.m.options; ip_len = 20 + 8 + DHCP_BASE_LEN + optlen; udp_len = 8 + DHCP_BASE_LEN + optlen; pkt.ip.ip_vhl = 0x45; /* IPv4 and hdrlen=5*4 */ pkt.ip.ip_tos = 0; pkt.ip.ip_len = htons(ip_len); pkt.ip.ip_id = htons(ip_id++); pkt.ip.ip_off = 0; pkt.ip.ip_ttl = 64; pkt.ip.ip_p = 17; /* proto UDP */ pkt.ip.ip_sum = 0; pkt.ip.ip_src = giaddr; if (inm.flags & htons(BOOTP_BROADCAST)) /* check bcast bit */ pkt.ip.ip_dst = 0xffffffff; /* 255.255.255.255 */ else pkt.ip.ip_dst = yiaddr.s_addr; pkt.ip.uh_sport = htons(BOOTPS); pkt.ip.uh_dport = htons(BOOTPC); pkt.ip.uh_ulen = htons(udp_len); pkt.ip.uh_sum = 0; pkt.ip.ip_sum = ~htons(ip4sum(0, &pkt.ip, 20)); sum = 17 + udp_len; sum = ip4sum(sum, &pkt.ip.ip_src, 8); sum = ip4sum(sum, &pkt.ip.uh_sport, udp_len); if (sum != 0xffff) pkt.ip.uh_sum = ~htons(sum); else pkt.ip.uh_sum = 0xffff; write_to_serial(slipfd, &pkt, ip_len); if (msg_type == DHCPACK) { printf("DHCPACK %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x IP %s\n", pkt.m.chaddr[0], pkt.m.chaddr[1], pkt.m.chaddr[2], pkt.m.chaddr[3], pkt.m.chaddr[4], pkt.m.chaddr[5], pkt.m.chaddr[6], pkt.m.chaddr[7], inet_ntoa(yiaddr)); /* ssystem("arp -s %s auto pub only", inet_ntoa(yiaddr)); */ } } /* * Internet checksum in host byte order. */ u_int16_t ip4sum(u_int16_t sum, const void *_p, u_int16_t len) { u_int16_t t; const u_int8_t *p = _p; const u_int8_t *end = p + len; while(p < (end-1)) { t = (p[0] << 8) + p[1]; sum += t; if (sum < t) sum++; p += 2; } if(p < end) { t = (p[0] << 8) + 0; sum += t; if (sum < t) sum++; } return sum; } int check_ip(const struct ip *ip, unsigned ip_len) { u_int16_t sum, ip_hl; /* Check IP version and length. */ if((ip->ip_vhl & IP_V) != IP_V4) return -1; if(ntohs(ip->ip_len) > ip_len) return -2; if(ntohs(ip->ip_len) < ip_len) return -3; /* Check IP header. */ ip_hl = 4*(ip->ip_vhl & IP_HL); sum = ip4sum(0, ip, ip_hl); if(sum != 0xffff && sum != 0x0) return -4; if(ip->ip_p == 6 || ip->ip_p == 17) { /* Check TCP or UDP header. */ u_int16_t tcp_len = ip_len - ip_hl; /* Sum pseudoheader. */ sum = ip->ip_p + tcp_len; /* proto and len, no carry */ sum = ip4sum(sum, &ip->ip_src, 8); /* src and dst */ /* Sum TCP/UDP header and data. */ sum = ip4sum(sum, (u_int8_t*)ip + ip_hl, tcp_len); /* Failed checksum test? */ if (sum != 0xffff && sum != 0x0) { if (ip->ip_p == 6) { /* TCP == 6 */ return -5; } else { /* UDP */ /* Deal with disabled UDP checksums. */ if (ip->uh_sum != 0) return -6; } } } else if (ip->ip_p == 1) { /* ICMP */ u_int16_t icmp_len = ip_len - ip_hl; sum = ip4sum(0, (u_int8_t*)ip + ip_hl, icmp_len); if(sum != 0xffff && sum != 0x0) return -7; } return 0; } int is_sensible_string(const unsigned char *s, int len) { int i; for(i = 1; i < len; i++) if (s[i] == 0 || s[i] == '\r' || s[i] == '\n' || s[i] == '\t') continue; else if (s[i] < ' ' || '~' < s[i]) return 0; return 1; } int ssystem(const char *fmt, ...) __attribute__((__format__ (__printf__, 1, 2))); int ssystem(const char *fmt, ...) { char cmd[128]; va_list ap; va_start(ap, fmt); vsnprintf(cmd, sizeof(cmd), fmt, ap); va_end(ap); printf("%s\n", cmd); return system(cmd); } #define SLIP_END 0300 #define SLIP_ESC 0333 #define SLIP_ESC_END 0334 #define SLIP_ESC_ESC 0335 /* * Read from serial, when we have a packet write it to tun. No output * buffering, input buffered by stdio. */ void serial_to_tun(FILE *inslip, int outfd) { static union { unsigned char inbuf[2000]; struct ip iphdr; } uip; static int inbufptr = 0; int ret; unsigned char c; read_more: if(inbufptr >= sizeof(uip.inbuf)) { inbufptr = 0; } ret = fread(&c, 1, 1, inslip); if(ret == -1) err(1, "serial_to_tun: read"); if(ret == 0) { clearerr(inslip); return; fprintf(stderr, "serial_to_tun: EOF\n"); exit(1); } /* fprintf(stderr, ".");*/ switch(c) { case SLIP_END: if(inbufptr > 0) { /* * Sanity checks. */ #define DEBUG_LINE_MARKER '\r' int ecode; ecode = check_ip(&uip.iphdr, inbufptr); if(ecode < 0 && inbufptr == 8 && strncmp(uip.inbuf, "=IPA", 4) == 0) { static struct in_addr ipa; inbufptr = 0; if(memcmp(&ipa, &uip.inbuf[4], sizeof(ipa)) == 0) break; memcpy(&ipa, &uip.inbuf[4], sizeof(ipa)); #ifdef linux ssystem("route add -net %s netmask %s dev %s", inet_ntoa(ipa), "255.255.255.255", tundev); #else ssystem("route add -net %s -netmask %s -interface %s", inet_ntoa(ipa), "255.255.255.255", tundev); #endif break; } else if(ecode < 0) { /* * If sensible ASCII string, print it as debug info! */ if (uip.inbuf[0] == DEBUG_LINE_MARKER) fwrite(uip.inbuf + 1, inbufptr - 1, 1, stderr); else if (is_sensible_string(uip.inbuf, inbufptr)) fwrite(uip.inbuf, inbufptr, 1, stderr); else fprintf(stderr, "serial_to_tun: drop packet len=%d ecode=%d\n", inbufptr, ecode); inbufptr = 0; break; } PROGRESS("s"); if (dhsock != -1) { struct ip *ip = (void *)uip.inbuf; if (ip->ip_p == 17 && ip->ip_dst == 0xffffffff /* UDP and broadcast */ && ip->uh_sport == ntohs(BOOTPC) && ip->uh_dport == ntohs(BOOTPS)){ relay_dhcp_to_server(ip, inbufptr); inbufptr = 0; } } if(write(outfd, uip.inbuf, inbufptr) != inbufptr) err(1, "serial_to_tun: write"); inbufptr = 0; } break; case SLIP_ESC: if(fread(&c, 1, 1, inslip) != 1) { clearerr(inslip); /* Put ESC back and give up! */ ungetc(SLIP_ESC, inslip); return; } switch(c) { case SLIP_ESC_END: c = SLIP_END; break; case SLIP_ESC_ESC: c = SLIP_ESC; break; } /* FALLTHROUGH */ default: uip.inbuf[inbufptr++] = c; break; } goto read_more; } unsigned char slip_buf[2000]; int slip_end, slip_begin; void slip_send(int fd, unsigned char c) { if (slip_end >= sizeof(slip_buf)) err(1, "slip_send overflow"); slip_buf[slip_end] = c; slip_end++; } int slip_empty() { return slip_end == 0; } void slip_flushbuf(int fd) { int n; if (slip_empty()) return; n = write(fd, slip_buf + slip_begin, (slip_end - slip_begin)); if (n == -1 && errno != EAGAIN) err(1, "slip_flushbuf write failed"); else if (n == -1) PROGRESS("Q"); /* Outqueueis full! */ else { slip_begin += n; if (slip_begin == slip_end) slip_begin = slip_end = 0; } } void write_to_serial(int outfd, void *inbuf, int len) { u_int8_t *p = inbuf; int i, ecode; struct ip *iphdr = inbuf; /* * Sanity checks. */ ecode = check_ip(inbuf, len); if(ecode < 0) { fprintf(stderr, "tun_to_serial: drop packet %d\n", ecode); return; } if (iphdr->ip_id == 0) { iphdr->ip_id = htons(ip_id++); iphdr->ip_sum = 0; iphdr->ip_sum = ~htons(ip4sum(0, iphdr, 20)); ecode = check_ip(inbuf, len); if(ecode < 0) { fprintf(stderr, "tun_to_serial: drop packet %d\n", ecode); return; } } /* It would be ``nice'' to send a SLIP_END here but it's not * really necessary. */ /* slip_send(outfd, SLIP_END); */ for(i = 0; i < len; i++) { switch(p[i]) { case SLIP_END: slip_send(outfd, SLIP_ESC); slip_send(outfd, SLIP_ESC_END); break; case SLIP_ESC: slip_send(outfd, SLIP_ESC); slip_send(outfd, SLIP_ESC_ESC); break; default: slip_send(outfd, p[i]); break; } } slip_send(outfd, SLIP_END); PROGRESS("t"); } /* * Read from tun, write to slip. */ void tun_to_serial(int infd, int outfd) { static union { unsigned char inbuf[2000]; struct ip iphdr; } uip; int size; if((size = read(infd, uip.inbuf, 2000)) == -1) err(1, "tun_to_serial: read"); write_to_serial(outfd, uip.inbuf, size); } #define BAUDRATE B57600 //#define BAUDRATE B38400 //#define BAUDRATE B19200 void stty_telos(int fd) { struct termios tty; speed_t speed = BAUDRATE; int i; if(tcflush(fd, TCIOFLUSH) == -1) err(1, "tcflush"); if(tcgetattr(fd, &tty) == -1) err(1, "tcgetattr"); cfmakeraw(&tty); /* Nonblocking read. */ tty.c_cc[VTIME] = 0; tty.c_cc[VMIN] = 0; tty.c_cflag &= ~CRTSCTS; tty.c_cflag &= ~HUPCL; tty.c_cflag &= ~CLOCAL; cfsetispeed(&tty, speed); cfsetospeed(&tty, speed); if(tcsetattr(fd, TCSAFLUSH, &tty) == -1) err(1, "tcsetattr"); #if 1 /* Nonblocking read and write. */ /* if(fcntl(fd, F_SETFL, O_NONBLOCK) == -1) err(1, "fcntl"); */ tty.c_cflag |= CLOCAL; if(tcsetattr(fd, TCSAFLUSH, &tty) == -1) err(1, "tcsetattr"); i = TIOCM_DTR; if(ioctl(fd, TIOCMBIS, &i) == -1) err(1, "ioctl"); #endif usleep(10*1000); /* Wait for hardware 10ms. */ /* Flush input and output buffers. */ if(tcflush(fd, TCIOFLUSH) == -1) err(1, "tcflush"); } int devopen(const char *dev, int flags) { char t[32]; strcpy(t, "/dev/"); strcat(t, dev); return open(t, flags); } #ifdef linux #include #include int tun_alloc(char *dev) { struct ifreq ifr; int fd, err; if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) return -1; memset(&ifr, 0, sizeof(ifr)); /* Flags: IFF_TUN - TUN device (no Ethernet headers) * IFF_TAP - TAP device * * IFF_NO_PI - Do not provide packet information */ ifr.ifr_flags = IFF_TUN | IFF_NO_PI; if(*dev != 0) strncpy(ifr.ifr_name, dev, IFNAMSIZ); if((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){ close(fd); return err; } strcpy(dev, ifr.ifr_name); return fd; } #else int tun_alloc(char *dev) { return devopen(dev, O_RDWR); } #endif const char *ipaddr; const char *netmask; void cleanup(void) { ssystem("ifconfig %s down", tundev); #ifndef linux ssystem("sysctl net.inet.ip.forwarding=0"); #endif /* ssystem("arp -d %s", ipaddr); */ ssystem("netstat -nr" " | awk '{ if ($2 == \"%s\") print \"route delete -net \"$1; }'" " | sh", tundev); } void sigcleanup(int signo) { fprintf(stderr, "signal %d\n", signo); exit(0); /* exit(0) will call cleanup() */ } void ifconf(const char *tundev, const char *ipaddr, const char *netmask) { struct in_addr netname; netname.s_addr = inet_addr(ipaddr) & inet_addr(netmask); #ifdef linux ssystem("ifconfig %s inet `hostname` up", tundev); if (strcmp(ipaddr, "0.0.0.0") != 0) ssystem("route add -net %s netmask %s dev %s", inet_ntoa(netname), netmask, tundev); #else ssystem("ifconfig %s inet up", tundev); if (strcmp(ipaddr, "0.0.0.0") != 0) ssystem("route add -net %s -netmask %s -interface %s", inet_ntoa(netname), netmask, tundev); ssystem("sysctl net.inet.ip.forwarding=1"); #endif /* !linux */ ssystem("ifconfig %s\n", tundev); } int main(int argc, char **argv) { int c; int tunfd, slipfd, maxfd; int ret; fd_set rset, wset; struct timeval timeout; const char helo[6] = { SLIP_END, '?', 'I', 'P', 'A', SLIP_END }; FILE *inslip; const char *siodev = NULL; const char *dhcp_server = NULL; u_int16_t myport = BOOTPS, dhport = BOOTPS; ip_id = getpid() * time(NULL); while ((c = getopt(argc, argv, "D:hs:t:")) != -1) { switch (c) { case 'D': dhcp_server = optarg; break; case 's': if (strncmp("/dev/", optarg, 5) == 0) siodev = optarg + 5; else siodev = optarg; break; case 't': if (strncmp("/dev/", optarg, 5) == 0) strcpy(tundev, optarg + 5); else strcpy(tundev, optarg); break; case '?': case 'h': default: err(1, "usage: tunslip [-s siodev] [-t tundev] [-D dhcp-server] ipaddress netmask [dhcp-server]"); break; } } argc -= (optind - 1); argv += (optind - 1); if (argc != 3 && argc != 4) err(1, "usage: tunslip [-s siodev] [-t tundev] [-D dhcp-server] ipaddress netmask [dhcp-server]"); ipaddr = argv[1]; netmask = argv[2]; circuit_addr = inet_addr(ipaddr); netaddr = inet_addr(ipaddr) & inet_addr(netmask); /* * Set up DHCP relay agent socket and find the address of this relay * agent. */ if (argc == 4) { dhcp_server = argv[3]; } if (dhcp_server != NULL) { struct sockaddr_in myaddr; socklen_t len; in_addr_t a; if (strchr(dhcp_server, ':') != NULL) { dhport = atoi(strchr(dhcp_server, ':') + 1); myport = dhport + 1; *strchr(dhcp_server, ':') = '\0'; } a = inet_addr(dhcp_server); if (a == -1) err(1, "illegal dhcp-server address"); #ifndef linux dhaddr.sin_len = sizeof(dhaddr); #endif dhaddr.sin_family = AF_INET; dhaddr.sin_port = htons(dhport); dhaddr.sin_addr.s_addr = a; dhsock = socket(AF_INET, SOCK_DGRAM, 0); if (dhsock < 0) err (1, "socket"); memset(&myaddr, 0x0, sizeof(myaddr)); #ifndef linux myaddr.sin_len = sizeof(myaddr); #endif myaddr.sin_family = AF_INET; myaddr.sin_addr.s_addr = INADDR_ANY; myaddr.sin_port = htons(myport); if (bind(dhsock, (struct sockaddr *)&myaddr, sizeof(myaddr)) < 0) err(1, "bind dhcp-relay"); if (connect(dhsock, (struct sockaddr *)&dhaddr, sizeof(dhaddr)) < 0) err(1, "connect to dhcp-server"); len = sizeof(myaddr); if (getsockname(dhsock, (struct sockaddr *)&myaddr, &len) < 0) err(1, "getsockname dhsock"); giaddr = myaddr.sin_addr.s_addr; /* * Don't want connected socket. */ close(dhsock); dhsock = socket(AF_INET, SOCK_DGRAM, 0); if (dhsock < 0) err (1, "socket"); myaddr.sin_family = AF_INET; myaddr.sin_addr.s_addr = INADDR_ANY; myaddr.sin_port = htons(myport); if (bind(dhsock, (struct sockaddr *)&myaddr, sizeof(myaddr)) < 0) err(1, "bind dhcp-relay"); fprintf(stderr, "DHCP server at %s:%d\n", dhcp_server, dhport); } if (siodev != NULL) { slipfd = devopen(siodev, O_RDWR | O_NONBLOCK); if (slipfd == -1) err(1, "can't open siodev ``/dev/%s''", siodev); } else { static const char *siodevs[] = { "ttyUSB0", "ucom0", "cuaU0" }; int i; for(i = 0; i < 3; i++) { siodev = siodevs[i]; slipfd = devopen(siodev, O_RDWR | O_NONBLOCK); if (slipfd != -1) break; } if (slipfd == -1) err(1, "can't open siodev"); } fprintf(stderr, "slip started on ``/dev/%s''\n", siodev); stty_telos(slipfd); slip_send(slipfd, SLIP_END); inslip = fdopen(slipfd, "r"); if(inslip == NULL) err(1, "main: fdopen"); tunfd = tun_alloc(tundev); if(tunfd == -1) err(1, "main: open"); fprintf(stderr, "opened device ``/dev/%s''\n", tundev); atexit(cleanup); signal(SIGHUP, sigcleanup); signal(SIGTERM, sigcleanup); signal(SIGINT, sigcleanup); ifconf(tundev, ipaddr, netmask); while(1) { maxfd = 0; FD_ZERO(&rset); FD_ZERO(&wset); if (!slip_empty()) /* Anything to flush? */ FD_SET(slipfd, &wset); FD_SET(slipfd, &rset); /* Read from slip ASAP! */ if(slipfd > maxfd) maxfd = slipfd; /* We only have one packet at a time queued for slip output. */ if(slip_empty()) { FD_SET(tunfd, &rset); if(tunfd > maxfd) maxfd = tunfd; if(dhsock != -1) { FD_SET(dhsock, &rset); if(dhsock > maxfd) maxfd = dhsock; } } timeout.tv_sec = 1; timeout.tv_usec = 450*1000; ret = select(maxfd + 1, &rset, &wset, NULL, &timeout); if(ret == -1) err(1, "select"); else if(ret == 0 && slip_empty()) { ret = write(slipfd, helo, sizeof(helo)); if(ret != sizeof(helo)) err(1, "write helo"); } else if(ret > 0) { if(FD_ISSET(slipfd, &rset)) serial_to_tun(inslip, tunfd); if(FD_ISSET(slipfd, &wset)) slip_flushbuf(slipfd); if(slip_empty() && FD_ISSET(tunfd, &rset)) { tun_to_serial(tunfd, slipfd); slip_flushbuf(slipfd); } if(dhsock != -1 && slip_empty() && FD_ISSET(dhsock, &rset)) { relay_dhcp_to_client(slipfd); slip_flushbuf(slipfd); } } else err(1, "select"); } }