* @file nat-pmp.c NAT-PMP Implementation * Purple is the legal property of its developers, whose names are too numerous * to list here. Please refer to the COPYRIGHT file distributed with this * Most code in nat-pmp.c copyright (C) 2007, R. Tyler Ballance, bleep, LLC. * This file is distributed under the 3-clause (modified) BSD license: * Redistribution and use in source and binary forms, with or without modification, are permitted * provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and * the following disclaimer. * Neither the name of the bleep. LLC nor the names of its contributors may be used to endorse or promote * products derived from this software without specific prior written permission. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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 /* We will need sysctl() and NET_RT_DUMP, both of which are not present * on all platforms, to continue. */ #if defined(HAVE_SYS_SYSCTL_H) && defined(NET_RT_DUMP) guint8 opcode; /* 128 + n */ struct _PurplePmpMapResponse { typedef struct _PurplePmpMapResponse PurplePmpMapResponse; PURPLE_PMP_STATUS_UNDISCOVERED = -1, PURPLE_PMP_STATUS_UNABLE_TO_DISCOVER, PURPLE_PMP_STATUS_DISCOVERING, PURPLE_PMP_STATUS_DISCOVERED static PurplePmpInfo pmp_info = {PURPLE_PMP_STATUS_UNDISCOVERED, NULL}; * Thanks to R. Matthew Emerson for the fixes on this #define PMP_MAP_OPCODE_UDP 1 #define PMP_MAP_OPCODE_TCP 2 #define PMP_TIMEOUT 250000 /* 250000 useconds */ /* alignment constraint for routing socket */ #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len)) get_rtaddrs(int bitmask, struct sockaddr *sa, struct sockaddr *addrs[]) for (i = 0; i < RTAX_MAX; i++) #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN sa = (struct sockaddr *)(ROUNDUP(sa->sa_len) + (char *)sa); if (sa->sa_family == AF_INET) sa = (struct sockaddr*)(sizeof(struct sockaddr_in) + (char *)sa); else if (sa->sa_family == AF_INET6) sa = (struct sockaddr*)(sizeof(struct sockaddr_in6) + (char *)sa); is_default_route(struct sockaddr *sa, struct sockaddr *mask) if (sa->sa_family != AF_INET) sin = (struct sockaddr_in *)sa; if ((sin->sin_addr.s_addr == INADDR_ANY) && (ntohl(((struct sockaddr_in *)mask)->sin_addr.s_addr) == 0L || #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN * The return sockaddr_in must be g_free()'d when no longer needed static struct sockaddr_in * struct sockaddr_in *sin = NULL; mib[1] = PF_ROUTE; /* entire routing table or a subset of it */ mib[2] = 0; /* protocol number - always 0 */ mib[3] = 0; /* address family - 0 for all addres families */ /* Determine the buffer side needed to get the full routing table */ if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) purple_debug_warning("nat-pmp", "sysctl: net.route.0.0.dump estimate\n"); if (!(buf = malloc(needed))) purple_debug_warning("nat-pmp", "Failed to malloc %" G_GSIZE_FORMAT "\n", needed); /* Read the routing table into buf */ if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) purple_debug_warning("nat-pmp", "sysctl: net.route.0.0.dump\n"); for (next = buf; next < lim; next += rtm->rtm_msglen) rtm = (struct rt_msghdr *)next; sa = (struct sockaddr *)(rtm + 1); if (sa->sa_family == AF_INET) struct sockaddr_in *cursin = (struct sockaddr_in*) sa; if ((rtm->rtm_flags & RTF_GATEWAY) && cursin->sin_addr.s_addr == INADDR_ANY) /* We found the default route. Now get the destination address and netmask. */ struct sockaddr *rti_info[RTAX_MAX]; struct sockaddr addr, mask; get_rtaddrs(rtm->rtm_addrs, sa, rti_info); memset(&addr, 0, sizeof(addr)); if (rtm->rtm_addrs & RTA_DST) memcpy(&addr, rti_info[RTAX_DST], sizeof(addr)); memset(&mask, 0, sizeof(mask)); if (rtm->rtm_addrs & RTA_NETMASK) memcpy(&mask, rti_info[RTAX_NETMASK], sizeof(mask)); if (rtm->rtm_addrs & RTA_GATEWAY && is_default_route(&addr, &mask)) if (rti_info[RTAX_GATEWAY]) { struct sockaddr_in *rti_sin = (struct sockaddr_in *)rti_info[RTAX_GATEWAY]; sin = g_new0(struct sockaddr_in, 1); sin->sin_family = rti_sin->sin_family; sin->sin_port = rti_sin->sin_port; sin->sin_addr.s_addr = rti_sin->sin_addr.s_addr; memcpy(sin, rti_info[RTAX_GATEWAY], sizeof(struct sockaddr_in)); purple_debug_info("nat-pmp", "Found a default gateway\n"); * purple_pmp_get_public_ip() will return the publicly facing IP address of the * default NAT gateway. The function will return NULL if: * - The gateway doesn't support NAT-PMP * - The gateway errors in some other spectacular fashion purple_pmp_get_public_ip() struct sockaddr_in addr, *gateway, *publicsockaddr = NULL; struct timeval req_timeout; PurplePmpIpResponse resp; if (pmp_info.status == PURPLE_PMP_STATUS_UNABLE_TO_DISCOVER) if ((pmp_info.status == PURPLE_PMP_STATUS_DISCOVERED) && (pmp_info.publicip != NULL)) purple_debug_info("nat-pmp", "Returning cached publicip %s\n",pmp_info.publicip); return pmp_info.publicip; purple_debug_info("nat-pmp", "Cannot request public IP from a NULL gateway!\n"); /* If we get a NULL gateway, don't try again next time */ pmp_info.status = PURPLE_PMP_STATUS_UNABLE_TO_DISCOVER; /* Default port for NAT-PMP is 5351 */ if (gateway->sin_port != PMP_PORT) gateway->sin_port = htons(PMP_PORT); req_timeout.tv_usec = PMP_TIMEOUT; sendfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); /* Clean out both req and resp structures */ memset(&req, 0, sizeof(PurplePmpIpRequest)); memset(&resp, 0, sizeof(PurplePmpIpResponse)); /* The NAT-PMP spec says we should attempt to contact the gateway 9 times, doubling the time we wait each time. * Even starting with a timeout of 0.1 seconds, that means that we have a total waiting of 204.6 seconds. * With the recommended timeout of 0.25 seconds, we're talking 511.5 seconds (8.5 minutes). * This seems really silly... if this were nonblocking, a couple retries might be in order, but it's not at present. purple_debug_info("nat-pmp", "Attempting to retrieve the public ip address for the NAT device at: %s\n", inet_ntoa(gateway->sin_addr)); purple_debug_info("nat-pmp", "\tTimeout: %ds %dus\n", req_timeout.tv_sec, req_timeout.tv_usec); /* TODO: Non-blocking! */ if (sendto(sendfd, &req, sizeof(req), 0, (struct sockaddr *)(gateway), sizeof(struct sockaddr)) < 0) purple_debug_info("nat-pmp", "There was an error sending the NAT-PMP public IP request! (%s)\n", g_strerror(errno)); pmp_info.status = PURPLE_PMP_STATUS_UNABLE_TO_DISCOVER; if (setsockopt(sendfd, SOL_SOCKET, SO_RCVTIMEO, &req_timeout, sizeof(req_timeout)) < 0) purple_debug_info("nat-pmp", "There was an error setting the socket's options! (%s)\n", g_strerror(errno)); pmp_info.status = PURPLE_PMP_STATUS_UNABLE_TO_DISCOVER; /* TODO: Non-blocking! */ len = sizeof(struct sockaddr_in); if (recvfrom(sendfd, &resp, sizeof(PurplePmpIpResponse), 0, (struct sockaddr *)(&addr), &len) < 0) purple_debug_info("nat-pmp", "There was an error receiving the response from the NAT-PMP device! (%s)\n", g_strerror(errno)); pmp_info.status = PURPLE_PMP_STATUS_UNABLE_TO_DISCOVER; if (addr.sin_addr.s_addr == gateway->sin_addr.s_addr) purple_debug_info("nat-pmp", "Response was not received from our gateway! Instead from: %s\n", inet_ntoa(addr.sin_addr)); pmp_info.status = PURPLE_PMP_STATUS_UNABLE_TO_DISCOVER; pmp_info.status = PURPLE_PMP_STATUS_UNABLE_TO_DISCOVER; purple_debug_info("nat-pmp", "Response received from NAT-PMP device:\n"); purple_debug_info("nat-pmp", "version: %d\n", resp.version); purple_debug_info("nat-pmp", "opcode: %d\n", resp.opcode); purple_debug_info("nat-pmp", "resultcode: %d\n", ntohs(resp.resultcode)); purple_debug_info("nat-pmp", "epoch: %d\n", ntohl(resp.epoch)); in.s_addr = resp.address; purple_debug_info("nat-pmp", "address: %s\n", inet_ntoa(in)); publicsockaddr->sin_addr.s_addr = resp.address; g_free(pmp_info.publicip); pmp_info.publicip = g_strdup(inet_ntoa(publicsockaddr->sin_addr)); pmp_info.status = PURPLE_PMP_STATUS_DISCOVERED; return inet_ntoa(publicsockaddr->sin_addr); purple_pmp_create_map(PurplePmpType type, unsigned short privateport, unsigned short publicport, int lifetime) struct sockaddr_in *gateway; struct timeval req_timeout; PurplePmpMapResponse *resp; purple_debug_info("nat-pmp", "Cannot create mapping on a NULL gateway!\n"); /* Default port for NAT-PMP is 5351 */ if (gateway->sin_port != PMP_PORT) gateway->sin_port = htons(PMP_PORT); resp = g_new0(PurplePmpMapResponse, 1); req_timeout.tv_usec = PMP_TIMEOUT; sendfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); memset(&req, 0, sizeof(PurplePmpMapRequest)); req.opcode = ((type == PURPLE_PMP_TYPE_UDP) ? PMP_MAP_OPCODE_UDP : PMP_MAP_OPCODE_TCP); req.privateport = htons(privateport); /* What a difference byte ordering makes...d'oh! */ req.publicport = htons(publicport); req.lifetime = htonl(lifetime); /* The NAT-PMP spec says we should attempt to contact the gateway 9 times, doubling the time we wait each time. * Even starting with a timeout of 0.1 seconds, that means that we have a total waiting of 204.6 seconds. * With the recommended timeout of 0.25 seconds, we're talking 511.5 seconds (8.5 minutes). * This seems really silly... if this were nonblocking, a couple retries might be in order, but it's not at present. * XXX Make this nonblocking. * XXX This code looks like the pmp_get_public_ip() code. Can it be consolidated? purple_debug_info("nat-pmp", "Attempting to create a NAT-PMP mapping the private port %d, and the public port %d\n", privateport, publicport); purple_debug_info("nat-pmp", "\tTimeout: %ds %dus\n", req_timeout.tv_sec, req_timeout.tv_usec); /* TODO: Non-blocking! */ success = (sendto(sendfd, &req, sizeof(req), 0, (struct sockaddr *)(gateway), sizeof(struct sockaddr)) >= 0); purple_debug_info("nat-pmp", "There was an error sending the NAT-PMP mapping request! (%s)\n", g_strerror(errno)); success = (setsockopt(sendfd, SOL_SOCKET, SO_RCVTIMEO, &req_timeout, sizeof(req_timeout)) >= 0); purple_debug_info("nat-pmp", "There was an error setting the socket's options! (%s)\n", g_strerror(errno)); /* The original code treats EAGAIN as a reason to iterate.. but I've removed iteration. This may be a problem */ /* TODO: Non-blocking! */ success = ((recvfrom(sendfd, resp, sizeof(PurplePmpMapResponse), 0, NULL, NULL) >= 0) || purple_debug_info("nat-pmp", "There was an error receiving the response from the NAT-PMP device! (%s)\n", g_strerror(errno)); success = (resp->opcode == (req.opcode + 128)); purple_debug_info("nat-pmp", "The opcode for the response from the NAT device (%i) does not match the request opcode (%i + 128 = %i)!\n", resp->opcode, req.opcode, req.opcode + 128); purple_debug_info("nat-pmp", "Response received from NAT-PMP device:\n"); purple_debug_info("nat-pmp", "version: %d\n", resp->version); purple_debug_info("nat-pmp", "opcode: %d\n", resp->opcode); purple_debug_info("nat-pmp", "resultcode: %d\n", ntohs(resp->resultcode)); purple_debug_info("nat-pmp", "epoch: %d\n", ntohl(resp->epoch)); purple_debug_info("nat-pmp", "privateport: %d\n", ntohs(resp->privateport)); purple_debug_info("nat-pmp", "publicport: %d\n", ntohs(resp->publicport)); purple_debug_info("nat-pmp", "lifetime: %d\n", ntohl(resp->lifetime)); /* XXX The private port may actually differ from the one we requested, according to the spec. * We don't handle that situation at present. * TODO: Look at the result and verify it matches what we wanted; either return a failure if it doesn't, * or change network.c to know what to do if the desired private port shifts as a result of the nat-pmp operation. purple_pmp_destroy_map(PurplePmpType type, unsigned short privateport) success = purple_pmp_create_map(((type == PURPLE_PMP_TYPE_UDP) ? PMP_MAP_OPCODE_UDP : PMP_MAP_OPCODE_TCP), purple_debug_warning("nat-pmp", "Failed to properly destroy mapping for %s port %d!\n", ((type == PURPLE_PMP_TYPE_UDP) ? "UDP" : "TCP"), privateport); purple_pmp_network_config_changed_cb(void *data) pmp_info.status = PURPLE_PMP_STATUS_UNDISCOVERED; g_free(pmp_info.publicip); pmp_info.publicip = NULL; purple_pmp_get_handle(void) purple_signal_connect(purple_network_get_handle(), "network-configuration-changed", purple_pmp_get_handle(), PURPLE_CALLBACK(purple_pmp_network_config_changed_cb), #else /* #ifdef NET_RT_DUMP */ purple_pmp_get_public_ip() purple_pmp_create_map(PurplePmpType type, unsigned short privateport, unsigned short publicport, int lifetime) purple_pmp_destroy_map(PurplePmpType type, unsigned short privateport) #endif /* #if !(defined(HAVE_SYS_SYCTL_H) && defined(NET_RT_DUMP)) */