/* This file is part of GNUnet. (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors) GNUnet is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /** * @file nat/nat.c * @brief Library handling UPnP and NAT-PMP port forwarding and * external IP address retrieval * @author Milan Bouchet-Valat * @author Christian Grothoff */ #include "platform.h" #include "gnunet_util_lib.h" #include "gnunet_resolver_service.h" #include "gnunet_nat_lib.h" #include "nat.h" #define LOG(kind,...) GNUNET_log_from (kind, "nat", __VA_ARGS__) /** * How often do we scan for changes in our IP address from our local * interfaces? */ #define IFC_SCAN_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 15) /** * How often do we scan for changes in how our hostname resolves? */ #define HOSTNAME_DNS_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 20) /** * How often do we scan for changes in how our external (dyndns) hostname resolves? */ #define DYNDNS_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 7) /** * How long until we give up trying to resolve our own hostname? */ #define HOSTNAME_RESOLVE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1) /** * Where did the given local address originate from? * To be used for debugging as well as in the future * to remove all addresses from a certain source when * we reevaluate the source. */ enum LocalAddressSource { /** * Address was obtained by DNS resolution of the external hostname * given in the configuration (i.e. hole-punched DynDNS setup). */ LAL_EXTERNAL_IP, /** * Address was obtained by looking up our own hostname in DNS. */ LAL_HOSTNAME_DNS, /** * Address was obtained by scanning our hosts's network interfaces * and taking their address (no DNS involved). */ LAL_INTERFACE_ADDRESS, /** * Addresses we were explicitly bound to. */ LAL_BINDTO_ADDRESS, /** * Addresses from UPnP or PMP */ LAL_UPNP, /** * End of the list. */ LAL_END }; /** * List of local addresses that we currently deem valid. Actual * struct is followed by the 'struct sockaddr'. Note that the code * intentionally makes no attempt to ensure that a particular address * is only listed once (especially since it may come from different * sources, and the source is an "internal" construct). */ struct LocalAddressList { /** * This is a linked list. */ struct LocalAddressList *next; /** * Previous entry. */ struct LocalAddressList *prev; /** * Number of bytes of address that follow. */ socklen_t addrlen; /** * Origin of the local address. */ enum LocalAddressSource source; }; /** * Handle for miniupnp-based NAT traversal actions. */ struct MiniList { /** * Doubly-linked list. */ struct MiniList *next; /** * Doubly-linked list. */ struct MiniList *prev; /** * Handle to mini-action. */ struct GNUNET_NAT_MiniHandle *mini; /** * Local port number that was mapped. */ uint16_t port; }; /** * Handle for active NAT registrations. */ struct GNUNET_NAT_Handle { /** * Configuration to use. */ const struct GNUNET_CONFIGURATION_Handle *cfg; /** * Function to call when we learn about a new address. */ GNUNET_NAT_AddressCallback address_callback; /** * Function to call when we notice another peer asking for * connection reversal. */ GNUNET_NAT_ReversalCallback reversal_callback; /** * Closure for 'callback'. */ void *callback_cls; /** * Handle for (DYN)DNS lookup of our external IP. */ struct GNUNET_RESOLVER_RequestHandle *ext_dns; /** * Handle for request of hostname resolution, non-NULL if pending. */ struct GNUNET_RESOLVER_RequestHandle *hostname_dns; /** * stdout pipe handle for the gnunet-helper-nat-server process */ struct GNUNET_DISK_PipeHandle *server_stdout; /** * stdout file handle (for reading) for the gnunet-helper-nat-server process */ const struct GNUNET_DISK_FileHandle *server_stdout_handle; /** * Linked list of currently valid addresses (head). */ struct LocalAddressList *lal_head; /** * Linked list of currently valid addresses (tail). */ struct LocalAddressList *lal_tail; /** * How long do we wait for restarting a crashed gnunet-helper-nat-server? */ struct GNUNET_TIME_Relative server_retry_delay; /** * ID of select gnunet-helper-nat-server stdout read task */ GNUNET_SCHEDULER_TaskIdentifier server_read_task; /** * ID of interface IP-scan task */ GNUNET_SCHEDULER_TaskIdentifier ifc_task; /** * ID of hostname DNS lookup task */ GNUNET_SCHEDULER_TaskIdentifier hostname_task; /** * ID of DynDNS lookup task */ GNUNET_SCHEDULER_TaskIdentifier dns_task; /** * ID of task to add addresses from bind. */ GNUNET_SCHEDULER_TaskIdentifier bind_task; /** * How often do we scan for changes in our IP address from our local * interfaces? */ struct GNUNET_TIME_Relative ifc_scan_frequency; /** * How often do we scan for changes in how our hostname resolves? */ struct GNUNET_TIME_Relative hostname_dns_frequency; /** * How often do we scan for changes in how our external (dyndns) hostname resolves? */ struct GNUNET_TIME_Relative dyndns_frequency; /** * The process id of the server process (if behind NAT) */ struct GNUNET_OS_Process *server_proc; /** * LAN address as passed by the caller (array). */ struct sockaddr **local_addrs; /** * Length of the 'local_addrs'. */ socklen_t *local_addrlens; /** * List of handles for UPnP-traversal, one per local port (if * not IPv6-only). */ struct MiniList *mini_head; /** * List of handles for UPnP-traversal, one per local port (if * not IPv6-only). */ struct MiniList *mini_tail; /** * Number of entries in 'local_addrs' array. */ unsigned int num_local_addrs; /** * Our external address (according to config, UPnP may disagree...), * in dotted decimal notation, IPv4-only. Or NULL if not known. */ char *external_address; /** * Presumably our internal address (according to config) */ char *internal_address; /** * Is this transport configured to be behind a NAT? */ int behind_nat; /** * Has the NAT been punched? (according to config) */ int nat_punched; /** * Is this transport configured to allow connections to NAT'd peers? */ int enable_nat_client; /** * Should we run the gnunet-helper-nat-server? */ int enable_nat_server; /** * Are we allowed to try UPnP/PMP for NAT traversal? */ int enable_upnp; /** * Should we use local addresses (loopback)? (according to config) */ int use_localaddresses; /** * Should we return local addresses to clients */ int return_localaddress; /** * Should we do a DNS lookup of our hostname to find out our own IP? */ int use_hostname; /** * Is using IPv6 disabled? */ int disable_ipv6; /** * Is this TCP or UDP? */ int is_tcp; /** * Port we advertise to the outside. */ uint16_t adv_port; }; /** * Try to start the gnunet-helper-nat-server (if it is not * already running). * * @param h handle to NAT */ static void start_gnunet_nat_server (struct GNUNET_NAT_Handle *h); /** * Remove all addresses from the list of 'local' addresses * that originated from the given source. * * @param h handle to NAT * @param src source that identifies addresses to remove */ static void remove_from_address_list_by_source (struct GNUNET_NAT_Handle *h, enum LocalAddressSource src) { struct LocalAddressList *pos; struct LocalAddressList *next; next = h->lal_head; while (NULL != (pos = next)) { next = pos->next; if (pos->source != src) continue; GNUNET_CONTAINER_DLL_remove (h->lal_head, h->lal_tail, pos); if (NULL != h->address_callback) h->address_callback (h->callback_cls, GNUNET_NO, (const struct sockaddr *) &pos[1], pos->addrlen); GNUNET_free (pos); } } /** * Add the given address to the list of 'local' addresses, thereby * making it a 'legal' address for this peer to have. * * @param h handle to NAT * @param src where did the local address originate from? * @param arg the address, some 'struct sockaddr' * @param arg_size number of bytes in arg */ static void add_to_address_list_as_is (struct GNUNET_NAT_Handle *h, enum LocalAddressSource src, const struct sockaddr *arg, socklen_t arg_size) { struct LocalAddressList *lal; lal = GNUNET_malloc (sizeof (struct LocalAddressList) + arg_size); memcpy (&lal[1], arg, arg_size); lal->addrlen = arg_size; lal->source = src; GNUNET_CONTAINER_DLL_insert (h->lal_head, h->lal_tail, lal); LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding address `%s' from source %d\n", GNUNET_a2s (arg, arg_size), src); if (NULL != h->address_callback) h->address_callback (h->callback_cls, GNUNET_YES, arg, arg_size); } /** * Add the given address to the list of 'local' addresses, thereby * making it a 'legal' address for this peer to have. Set the * port number in the process to the advertised port and possibly * also to zero (if we have the gnunet-helper-nat-server). * * @param h handle to NAT * @param src where did the local address originate from? * @param arg the address, some 'struct sockaddr' * @param arg_size number of bytes in arg */ static void add_to_address_list (struct GNUNET_NAT_Handle *h, enum LocalAddressSource src, const struct sockaddr *arg, socklen_t arg_size) { struct sockaddr_in s4; const struct sockaddr_in *in4; struct sockaddr_in6 s6; const struct sockaddr_in6 *in6; if (arg_size == sizeof (struct sockaddr_in)) { in4 = (const struct sockaddr_in *) arg; s4 = *in4; s4.sin_port = htons (h->adv_port); add_to_address_list_as_is (h, src, (const struct sockaddr *) &s4, sizeof (struct sockaddr_in)); if (GNUNET_YES == h->enable_nat_server) { /* also add with PORT = 0 to indicate NAT server is enabled */ s4.sin_port = htons (0); add_to_address_list_as_is (h, src, (const struct sockaddr *) &s4, sizeof (struct sockaddr_in)); } } else if (arg_size == sizeof (struct sockaddr_in6)) { if (GNUNET_YES != h->disable_ipv6) { in6 = (const struct sockaddr_in6 *) arg; s6 = *in6; s6.sin6_port = htons (h->adv_port); add_to_address_list_as_is (h, src, (const struct sockaddr *) &s6, sizeof (struct sockaddr_in6)); } } else { GNUNET_assert (0); } } /** * Add the given IP address to the list of 'local' addresses, thereby * making it a 'legal' address for this peer to have. * * @param h handle to NAT * @param src where did the local address originate from? * @param addr the address, some 'struct in_addr' or 'struct in6_addr' * @param addrlen number of bytes in addr */ static void add_ip_to_address_list (struct GNUNET_NAT_Handle *h, enum LocalAddressSource src, const void *addr, socklen_t addrlen) { struct sockaddr_in s4; const struct in_addr *in4; struct sockaddr_in6 s6; const struct in6_addr *in6; if (addrlen == sizeof (struct in_addr)) { in4 = (const struct in_addr *) addr; memset (&s4, 0, sizeof (s4)); s4.sin_family = AF_INET; s4.sin_port = 0; #if HAVE_SOCKADDR_IN_SIN_LEN s4.sin_len = (u_char) sizeof (struct sockaddr_in); #endif s4.sin_addr = *in4; add_to_address_list (h, src, (const struct sockaddr *) &s4, sizeof (struct sockaddr_in)); if (GNUNET_YES == h->enable_nat_server) { /* also add with PORT = 0 to indicate NAT server is enabled */ s4.sin_port = htons (0); add_to_address_list (h, src, (const struct sockaddr *) &s4, sizeof (struct sockaddr_in)); } } else if (addrlen == sizeof (struct in6_addr)) { if (GNUNET_YES != h->disable_ipv6) { in6 = (const struct in6_addr *) addr; memset (&s6, 0, sizeof (s6)); s6.sin6_family = AF_INET6; s6.sin6_port = htons (h->adv_port); #if HAVE_SOCKADDR_IN_SIN_LEN s6.sin6_len = (u_char) sizeof (struct sockaddr_in6); #endif s6.sin6_addr = *in6; add_to_address_list (h, src, (const struct sockaddr *) &s6, sizeof (struct sockaddr_in6)); } } else { GNUNET_assert (0); } } /** * Task to do DNS lookup on our external hostname to * get DynDNS-IP addresses. * * @param cls the NAT handle * @param tc scheduler context */ static void resolve_dns (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc); /** * Our (external) hostname was resolved and the configuration says that * the NAT was hole-punched. * * @param cls the 'struct Plugin' * @param addr NULL on error, otherwise result of DNS lookup * @param addrlen number of bytes in addr */ static void process_external_ip (void *cls, const struct sockaddr *addr, socklen_t addrlen) { struct GNUNET_NAT_Handle *h = cls; struct in_addr dummy; if (addr == NULL) { h->ext_dns = NULL; if (1 == inet_pton (AF_INET, h->external_address, &dummy)) return; /* repated lookup pointless: was numeric! */ h->dns_task = GNUNET_SCHEDULER_add_delayed (h->dyndns_frequency, &resolve_dns, h); return; } add_to_address_list (h, LAL_EXTERNAL_IP, addr, addrlen); } /** * Task to do a lookup on our hostname for IP addresses. * * @param cls the NAT handle * @param tc scheduler context */ static void resolve_hostname (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc); /** * Function called by the resolver for each address obtained from DNS * for our own hostname. Add the addresses to the list of our IP * addresses. * * @param cls closure * @param addr one of the addresses of the host, NULL for the last address * @param addrlen length of the address */ static void process_hostname_ip (void *cls, const struct sockaddr *addr, socklen_t addrlen) { struct GNUNET_NAT_Handle *h = cls; if (addr == NULL) { h->hostname_dns = NULL; h->hostname_task = GNUNET_SCHEDULER_add_delayed (h->hostname_dns_frequency, &resolve_hostname, h); return; } add_to_address_list (h, LAL_HOSTNAME_DNS, addr, addrlen); } /** * Add the IP of our network interface to the list of * our IP addresses. * * @param cls the 'struct GNUNET_NAT_Handle' * @param name name of the interface * @param isDefault do we think this may be our default interface * @param addr address of the interface * @param broadcast_addr the broadcast address (can be NULL for unknown or unassigned) * @param netmask the network mask (can be NULL for unknown or unassigned)) * @param addrlen number of bytes in addr * @return GNUNET_OK to continue iterating */ static int process_interfaces (void *cls, const char *name, int isDefault, const struct sockaddr *addr, const struct sockaddr *broadcast_addr, const struct sockaddr *netmask, socklen_t addrlen) { struct GNUNET_NAT_Handle *h = cls; const struct sockaddr_in *s4; const struct sockaddr_in6 *s6; const void *ip; char buf[INET6_ADDRSTRLEN]; switch (addr->sa_family) { case AF_INET: s4 = (struct sockaddr_in *) addr; ip = &s4->sin_addr; /* Check if address is in 127.0.0.0/8 */ uint32_t address = ntohl ((uint32_t) (s4->sin_addr.s_addr)); uint32_t value = (address & 0xFF000000) ^ 0x7F000000; if ((h->return_localaddress == GNUNET_NO) && (value == 0)) { return GNUNET_OK; } if (GNUNET_YES == h->use_localaddresses) { add_ip_to_address_list (h, LAL_INTERFACE_ADDRESS, &s4->sin_addr, sizeof (struct in_addr)); } break; case AF_INET6: s6 = (struct sockaddr_in6 *) addr; if (IN6_IS_ADDR_LINKLOCAL (&((struct sockaddr_in6 *) addr)->sin6_addr)) { /* skip link local addresses */ return GNUNET_OK; } if ((h->return_localaddress == GNUNET_NO) && (IN6_IS_ADDR_LOOPBACK (&((struct sockaddr_in6 *) addr)->sin6_addr))) { return GNUNET_OK; } ip = &s6->sin6_addr; if (GNUNET_YES == h->use_localaddresses) { add_ip_to_address_list (h, LAL_INTERFACE_ADDRESS, &s6->sin6_addr, sizeof (struct in6_addr)); } break; default: GNUNET_break (0); return GNUNET_OK; } if ((h->internal_address == NULL) && (h->server_proc == NULL) && (h->server_read_task == GNUNET_SCHEDULER_NO_TASK) && (GNUNET_YES == isDefault) && ((addr->sa_family == AF_INET) || (addr->sa_family == AF_INET6))) { /* no internal address configured, but we found a "default" * interface, try using that as our 'internal' address */ h->internal_address = GNUNET_strdup (inet_ntop (addr->sa_family, ip, buf, sizeof (buf))); start_gnunet_nat_server (h); } return GNUNET_OK; } /** * Task that restarts the gnunet-helper-nat-server process after a crash * after a certain delay. * * @param cls the 'struct GNUNET_NAT_Handle' * @param tc scheduler context */ static void restart_nat_server (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_NAT_Handle *h = cls; h->server_read_task = GNUNET_SCHEDULER_NO_TASK; if ((tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN) != 0) return; start_gnunet_nat_server (h); } /** * We have been notified that gnunet-helper-nat-server has written something to stdout. * Handle the output, then reschedule this function to be called again once * more is available. * * @param cls the NAT handle * @param tc the scheduling context */ static void nat_server_read (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_NAT_Handle *h = cls; char mybuf[40]; ssize_t bytes; size_t i; int port; const char *port_start; struct sockaddr_in sin_addr; h->server_read_task = GNUNET_SCHEDULER_NO_TASK; if ((tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN) != 0) return; memset (mybuf, 0, sizeof (mybuf)); bytes = GNUNET_DISK_file_read (h->server_stdout_handle, mybuf, sizeof (mybuf)); if (bytes < 1) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Finished reading from server stdout with code: %d\n", bytes); if (0 != GNUNET_OS_process_kill (h->server_proc, SIGTERM)) GNUNET_log_from_strerror (GNUNET_ERROR_TYPE_WARNING, "nat", "kill"); GNUNET_OS_process_wait (h->server_proc); GNUNET_OS_process_destroy (h->server_proc); h->server_proc = NULL; GNUNET_DISK_pipe_close (h->server_stdout); h->server_stdout = NULL; h->server_stdout_handle = NULL; /* now try to restart it */ h->server_retry_delay = GNUNET_TIME_relative_multiply (h->server_retry_delay, 2); h->server_retry_delay = GNUNET_TIME_relative_max (GNUNET_TIME_UNIT_HOURS, h->server_retry_delay); h->server_read_task = GNUNET_SCHEDULER_add_delayed (h->server_retry_delay, &restart_nat_server, h); return; } port_start = NULL; for (i = 0; i < sizeof (mybuf); i++) { if (mybuf[i] == '\n') { mybuf[i] = '\0'; break; } if ((mybuf[i] == ':') && (i + 1 < sizeof (mybuf))) { mybuf[i] = '\0'; port_start = &mybuf[i + 1]; } } /* construct socket address of sender */ memset (&sin_addr, 0, sizeof (sin_addr)); sin_addr.sin_family = AF_INET; #if HAVE_SOCKADDR_IN_SIN_LEN sin_addr.sin_len = sizeof (sin_addr); #endif if ((NULL == port_start) || (1 != SSCANF (port_start, "%d", &port)) || (-1 == inet_pton (AF_INET, mybuf, &sin_addr.sin_addr))) { /* should we restart gnunet-helper-nat-server? */ LOG (GNUNET_ERROR_TYPE_WARNING, "nat", _("gnunet-helper-nat-server generated malformed address `%s'\n"), mybuf); h->server_read_task = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, h->server_stdout_handle, &nat_server_read, h); return; } sin_addr.sin_port = htons ((uint16_t) port); LOG (GNUNET_ERROR_TYPE_DEBUG, "gnunet-helper-nat-server read: %s:%d\n", mybuf, port); h->reversal_callback (h->callback_cls, (const struct sockaddr *) &sin_addr, sizeof (sin_addr)); h->server_read_task = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, h->server_stdout_handle, &nat_server_read, h); } /** * Try to start the gnunet-helper-nat-server (if it is not * already running). * * @param h handle to NAT */ static void start_gnunet_nat_server (struct GNUNET_NAT_Handle *h) { if ((h->behind_nat == GNUNET_YES) && (h->enable_nat_server == GNUNET_YES) && (h->internal_address != NULL) && (NULL != (h->server_stdout = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_YES, GNUNET_NO, GNUNET_YES)))) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Starting `%s' at `%s'\n", "gnunet-helper-nat-server", h->internal_address); /* Start the server process */ h->server_proc = GNUNET_OS_start_process (GNUNET_NO, NULL, h->server_stdout, "gnunet-helper-nat-server", "gnunet-helper-nat-server", h->internal_address, NULL); if (h->server_proc == NULL) { LOG (GNUNET_ERROR_TYPE_WARNING, "nat", _("Failed to start %s\n"), "gnunet-helper-nat-server"); GNUNET_DISK_pipe_close (h->server_stdout); h->server_stdout = NULL; } else { /* Close the write end of the read pipe */ GNUNET_DISK_pipe_close_end (h->server_stdout, GNUNET_DISK_PIPE_END_WRITE); h->server_stdout_handle = GNUNET_DISK_pipe_handle (h->server_stdout, GNUNET_DISK_PIPE_END_READ); h->server_read_task = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, h->server_stdout_handle, &nat_server_read, h); } } } /** * Task to scan the local network interfaces for IP addresses. * * @param cls the NAT handle * @param tc scheduler context */ static void list_interfaces (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_NAT_Handle *h = cls; h->ifc_task = GNUNET_SCHEDULER_NO_TASK; remove_from_address_list_by_source (h, LAL_INTERFACE_ADDRESS); GNUNET_OS_network_interfaces_list (&process_interfaces, h); h->ifc_task = GNUNET_SCHEDULER_add_delayed (h->ifc_scan_frequency, &list_interfaces, h); } /** * Task to do a lookup on our hostname for IP addresses. * * @param cls the NAT handle * @param tc scheduler context */ static void resolve_hostname (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_NAT_Handle *h = cls; h->hostname_task = GNUNET_SCHEDULER_NO_TASK; remove_from_address_list_by_source (h, LAL_HOSTNAME_DNS); h->hostname_dns = GNUNET_RESOLVER_hostname_resolve (AF_UNSPEC, HOSTNAME_RESOLVE_TIMEOUT, &process_hostname_ip, h); } /** * Task to do DNS lookup on our external hostname to * get DynDNS-IP addresses. * * @param cls the NAT handle * @param tc scheduler context */ static void resolve_dns (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_NAT_Handle *h = cls; h->dns_task = GNUNET_SCHEDULER_NO_TASK; remove_from_address_list_by_source (h, LAL_EXTERNAL_IP); h->ext_dns = GNUNET_RESOLVER_ip_get (h->external_address, AF_INET, GNUNET_TIME_UNIT_MINUTES, &process_external_ip, h); } /** * Add or remove UPnP-mapped addresses. * * @param cls the GNUNET_NAT_Handle * @param add_remove GNUNET_YES to mean the new public IP address, GNUNET_NO to mean * the previous (now invalid) one * @param addr either the previous or the new public IP address * @param addrlen actual lenght of the address */ static void upnp_add (void *cls, int add_remove, const struct sockaddr *addr, socklen_t addrlen) { struct GNUNET_NAT_Handle *h = cls; struct LocalAddressList *pos; struct LocalAddressList *next; if (GNUNET_YES == add_remove) { add_to_address_list (h, LAL_UPNP, addr, addrlen); return; } /* remove address */ next = h->lal_head; while (NULL != (pos = next)) { next = pos->next; if ((pos->source != LAL_UPNP) || (pos->addrlen != addrlen) || (0 != memcmp (&pos[1], addr, addrlen))) continue; GNUNET_CONTAINER_DLL_remove (h->lal_head, h->lal_tail, pos); if (NULL != h->address_callback) h->address_callback (h->callback_cls, GNUNET_NO, (const struct sockaddr *) &pos[1], pos->addrlen); GNUNET_free (pos); return; /* only remove once */ } /* asked to remove address that does not exist */ GNUNET_break (0); } /** * Try to add a port mapping using UPnP. * * @param h overall NAT handle * @param port port to map with UPnP */ static void add_minis (struct GNUNET_NAT_Handle *h, uint16_t port) { struct MiniList *ml; ml = h->mini_head; while (NULL != ml) { if (port == ml->port) return; /* already got this port */ ml = ml->next; } ml = GNUNET_malloc (sizeof (struct MiniList)); ml->port = port; ml->mini = GNUNET_NAT_mini_map_start (port, h->is_tcp, &upnp_add, h); GNUNET_CONTAINER_DLL_insert (h->mini_head, h->mini_tail, ml); } /** * Task to add addresses from original bind to set of valid addrs. * * @param cls the NAT handle * @param tc scheduler context */ static void add_from_bind (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { static struct in6_addr any = IN6ADDR_ANY_INIT; struct GNUNET_NAT_Handle *h = cls; unsigned int i; struct sockaddr *sa; const struct sockaddr_in *v4; h->bind_task = GNUNET_SCHEDULER_NO_TASK; for (i = 0; i < h->num_local_addrs; i++) { sa = h->local_addrs[i]; switch (sa->sa_family) { case AF_INET: if (sizeof (struct sockaddr_in) != h->local_addrlens[i]) { GNUNET_break (0); break; } v4 = (const struct sockaddr_in *) sa; if (0 != v4->sin_addr.s_addr) add_to_address_list (h, LAL_BINDTO_ADDRESS, sa, sizeof (struct sockaddr_in)); if (h->enable_upnp) add_minis (h, ntohs (v4->sin_port)); break; case AF_INET6: if (sizeof (struct sockaddr_in6) != h->local_addrlens[i]) { GNUNET_break (0); break; } if (0 != memcmp (&((const struct sockaddr_in6 *) sa)->sin6_addr, &any, sizeof (struct in6_addr))) add_to_address_list (h, LAL_BINDTO_ADDRESS, sa, sizeof (struct sockaddr_in6)); break; default: break; } } } /** * Attempt to enable port redirection and detect public IP address contacting * UPnP or NAT-PMP routers on the local network. Use addr to specify to which * of the local host's addresses should the external port be mapped. The port * is taken from the corresponding sockaddr_in[6] field. * * @param cfg configuration to use * @param is_tcp GNUNET_YES for TCP, GNUNET_NO for UDP * @param adv_port advertised port (port we are either bound to or that our OS * locally performs redirection from to our bound port). * @param num_addrs number of addresses in 'addrs' * @param addrs the local addresses packets should be redirected to * @param addrlens actual lengths of the addresses * @param address_callback function to call everytime the public IP address changes * @param reversal_callback function to call if someone wants connection reversal from us * @param callback_cls closure for callbacks * @return NULL on error, otherwise handle that can be used to unregister */ struct GNUNET_NAT_Handle * GNUNET_NAT_register (const struct GNUNET_CONFIGURATION_Handle *cfg, int is_tcp, uint16_t adv_port, unsigned int num_addrs, const struct sockaddr **addrs, const socklen_t * addrlens, GNUNET_NAT_AddressCallback address_callback, GNUNET_NAT_ReversalCallback reversal_callback, void *callback_cls) { struct GNUNET_NAT_Handle *h; struct in_addr in_addr; unsigned int i; LOG (GNUNET_ERROR_TYPE_DEBUG, "Registered with NAT service at port %u with %u IP bound local addresses\n", (unsigned int) adv_port, num_addrs); h = GNUNET_malloc (sizeof (struct GNUNET_NAT_Handle)); h->server_retry_delay = GNUNET_TIME_UNIT_SECONDS; h->cfg = cfg; h->is_tcp = is_tcp; h->address_callback = address_callback; h->reversal_callback = reversal_callback; h->callback_cls = callback_cls; h->num_local_addrs = num_addrs; h->adv_port = adv_port; if (num_addrs != 0) { h->local_addrs = GNUNET_malloc (num_addrs * sizeof (struct sockaddr *)); h->local_addrlens = GNUNET_malloc (num_addrs * sizeof (socklen_t)); for (i = 0; i < num_addrs; i++) { GNUNET_assert (addrlens[i] > 0); GNUNET_assert (addrs[i] != NULL); h->local_addrlens[i] = addrlens[i]; h->local_addrs[i] = GNUNET_malloc (addrlens[i]); memcpy (h->local_addrs[i], addrs[i], addrlens[i]); } } h->bind_task = GNUNET_SCHEDULER_add_now (&add_from_bind, h); if (GNUNET_OK == GNUNET_CONFIGURATION_have_value (cfg, "nat", "INTERNAL_ADDRESS")) { (void) GNUNET_CONFIGURATION_get_value_string (cfg, "nat", "INTERNAL_ADDRESS", &h->internal_address); } if ((h->internal_address != NULL) && (inet_pton (AF_INET, h->internal_address, &in_addr) != 1)) { LOG (GNUNET_ERROR_TYPE_WARNING, "nat", _("Malformed %s `%s' given in configuration!\n"), "INTERNAL_ADDRESS", h->internal_address); GNUNET_free (h->internal_address); h->internal_address = NULL; } if (GNUNET_OK == GNUNET_CONFIGURATION_have_value (cfg, "nat", "EXTERNAL_ADDRESS")) { (void) GNUNET_CONFIGURATION_get_value_string (cfg, "nat", "EXTERNAL_ADDRESS", &h->external_address); } h->behind_nat = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "BEHIND_NAT"); h->nat_punched = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "PUNCHED_NAT"); h->enable_nat_client = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "ENABLE_ICMP_CLIENT"); h->enable_nat_server = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "ENABLE_ICMP_SERVER"); h->enable_upnp = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "ENABLE_UPNP"); h->use_localaddresses = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "USE_LOCALADDR"); h->return_localaddress = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "RETURN_LOCAL_ADDRESSES"); h->use_hostname = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "USE_HOSTNAME"); h->disable_ipv6 = GNUNET_CONFIGURATION_get_value_yesno (cfg, "nat", "DISABLEV6"); if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_time (cfg, "nat", "DYNDNS_FREQUENCY", &h->dyndns_frequency)) h->dyndns_frequency = DYNDNS_FREQUENCY; if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_time (cfg, "nat", "IFC_SCAN_FREQUENCY", &h->ifc_scan_frequency)) h->ifc_scan_frequency = IFC_SCAN_FREQUENCY; if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_time (cfg, "nat", "HOSTNAME_DNS_FREQUENCY", &h->hostname_dns_frequency)) h->hostname_dns_frequency = HOSTNAME_DNS_FREQUENCY; if (NULL == reversal_callback) h->enable_nat_server = GNUNET_NO; /* Check if NAT was hole-punched */ if ((NULL != h->address_callback) && (h->external_address != NULL) && (h->nat_punched == GNUNET_YES)) { h->dns_task = GNUNET_SCHEDULER_add_now (&resolve_dns, h); h->enable_nat_server = GNUNET_NO; h->enable_upnp = GNUNET_NO; } /* Test for SUID binaries */ if ((h->behind_nat == GNUNET_YES) && (GNUNET_YES == h->enable_nat_server) && (GNUNET_YES != GNUNET_OS_check_helper_binary ("gnunet-helper-nat-server"))) { h->enable_nat_server = GNUNET_NO; LOG (GNUNET_ERROR_TYPE_WARNING, _ ("Configuration requires `%s', but binary is not installed properly (SUID bit not set). Option disabled.\n"), "gnunet-helper-nat-server"); } if ((GNUNET_YES == h->enable_nat_client) && (GNUNET_YES != GNUNET_OS_check_helper_binary ("gnunet-helper-nat-client"))) { h->enable_nat_client = GNUNET_NO; LOG (GNUNET_ERROR_TYPE_WARNING, _ ("Configuration requires `%s', but binary is not installed properly (SUID bit not set). Option disabled.\n"), "gnunet-helper-nat-client"); } start_gnunet_nat_server (h); /* FIXME: add support for UPnP, etc */ if (NULL != h->address_callback) { h->ifc_task = GNUNET_SCHEDULER_add_now (&list_interfaces, h); if (GNUNET_YES == h->use_hostname) h->hostname_task = GNUNET_SCHEDULER_add_now (&resolve_hostname, h); } return h; } /** * Stop port redirection and public IP address detection for the given handle. * This frees the handle, after having sent the needed commands to close open ports. * * @param h the handle to stop */ void GNUNET_NAT_unregister (struct GNUNET_NAT_Handle *h) { unsigned int i; struct LocalAddressList *lal; struct MiniList *ml; while (NULL != (ml = h->mini_head)) { GNUNET_CONTAINER_DLL_remove (h->mini_head, h->mini_tail, ml); if (NULL != ml->mini) GNUNET_NAT_mini_map_stop (ml->mini); GNUNET_free (ml); } if (h->ext_dns != NULL) { GNUNET_RESOLVER_request_cancel (h->ext_dns); h->ext_dns = NULL; } if (NULL != h->hostname_dns) { GNUNET_RESOLVER_request_cancel (h->hostname_dns); h->hostname_dns = NULL; } if (GNUNET_SCHEDULER_NO_TASK != h->server_read_task) { GNUNET_SCHEDULER_cancel (h->server_read_task); h->server_read_task = GNUNET_SCHEDULER_NO_TASK; } if (GNUNET_SCHEDULER_NO_TASK != h->bind_task) { GNUNET_SCHEDULER_cancel (h->bind_task); h->bind_task = GNUNET_SCHEDULER_NO_TASK; } if (GNUNET_SCHEDULER_NO_TASK != h->ifc_task) { GNUNET_SCHEDULER_cancel (h->ifc_task); h->ifc_task = GNUNET_SCHEDULER_NO_TASK; } if (GNUNET_SCHEDULER_NO_TASK != h->hostname_task) { GNUNET_SCHEDULER_cancel (h->hostname_task); h->hostname_task = GNUNET_SCHEDULER_NO_TASK; } if (GNUNET_SCHEDULER_NO_TASK != h->dns_task) { GNUNET_SCHEDULER_cancel (h->dns_task); h->dns_task = GNUNET_SCHEDULER_NO_TASK; } if (NULL != h->server_proc) { if (0 != GNUNET_OS_process_kill (h->server_proc, SIGTERM)) GNUNET_log_from_strerror (GNUNET_ERROR_TYPE_WARNING, "nat", "kill"); GNUNET_OS_process_wait (h->server_proc); GNUNET_OS_process_destroy (h->server_proc); h->server_proc = NULL; GNUNET_DISK_pipe_close (h->server_stdout); h->server_stdout = NULL; h->server_stdout_handle = NULL; } if (NULL != h->server_stdout) { GNUNET_DISK_pipe_close (h->server_stdout); h->server_stdout = NULL; h->server_stdout_handle = NULL; } while (NULL != (lal = h->lal_head)) { GNUNET_CONTAINER_DLL_remove (h->lal_head, h->lal_tail, lal); if (NULL != h->address_callback) h->address_callback (h->callback_cls, GNUNET_NO, (const struct sockaddr *) &lal[1], lal->addrlen); GNUNET_free (lal); } for (i = 0; i < h->num_local_addrs; i++) GNUNET_free (h->local_addrs[i]); GNUNET_free_non_null (h->local_addrs); GNUNET_free_non_null (h->local_addrlens); GNUNET_free_non_null (h->external_address); GNUNET_free_non_null (h->internal_address); GNUNET_free (h); } /** * We learned about a peer (possibly behind NAT) so run the * gnunet-helper-nat-client to send dummy ICMP responses to cause * that peer to connect to us (connection reversal). * * @return GNUNET_SYSERR on error, GNUNET_NO if nat client is disabled, * GNUNET_OK otherwise */ int GNUNET_NAT_run_client (struct GNUNET_NAT_Handle *h, const struct sockaddr_in *sa) { char inet4[INET_ADDRSTRLEN]; char port_as_string[6]; struct GNUNET_OS_Process *proc; if (GNUNET_YES != h->enable_nat_client) return GNUNET_NO; /* not permitted / possible */ if (h->internal_address == NULL) { LOG (GNUNET_ERROR_TYPE_WARNING, "nat", _ ("Internal IP address not known, cannot use ICMP NAT traversal method\n")); return GNUNET_SYSERR; } GNUNET_assert (sa->sin_family == AF_INET); if (NULL == inet_ntop (AF_INET, &sa->sin_addr, inet4, INET_ADDRSTRLEN)) { GNUNET_log_from_strerror (GNUNET_ERROR_TYPE_WARNING, "nat", "inet_ntop"); return GNUNET_SYSERR; } GNUNET_snprintf (port_as_string, sizeof (port_as_string), "%d", h->adv_port); LOG (GNUNET_ERROR_TYPE_DEBUG, _("Running gnunet-helper-nat-client %s %s %u\n"), h->internal_address, inet4, (unsigned int) h->adv_port); proc = GNUNET_OS_start_process (GNUNET_NO, NULL, NULL, "gnunet-helper-nat-client", "gnunet-helper-nat-client", h->internal_address, inet4, port_as_string, NULL); if (NULL == proc) return GNUNET_SYSERR; /* we know that the gnunet-helper-nat-client will terminate virtually * instantly */ GNUNET_OS_process_wait (proc); GNUNET_OS_process_destroy (proc); return GNUNET_OK; } /** * Test if the given address is (currently) a plausible IP address for this peer. * * @param h the handle returned by register * @param addr IP address to test (IPv4 or IPv6) * @param addrlen number of bytes in addr * @return GNUNET_YES if the address is plausible, * GNUNET_NO if the address is not plausible, * GNUNET_SYSERR if the address is malformed */ int GNUNET_NAT_test_address (struct GNUNET_NAT_Handle *h, const void *addr, socklen_t addrlen) { struct LocalAddressList *pos; const struct sockaddr_in *in4; const struct sockaddr_in6 *in6; if ((addrlen != sizeof (struct in_addr)) && (addrlen != sizeof (struct in6_addr))) { GNUNET_break (0); return GNUNET_SYSERR; } pos = h->lal_head; while (NULL != pos) { if (pos->addrlen == sizeof (struct sockaddr_in)) { in4 = (struct sockaddr_in *) &pos[1]; if ((addrlen == sizeof (struct in_addr)) && (0 == memcmp (&in4->sin_addr, addr, sizeof (struct in_addr)))) return GNUNET_YES; } else if (pos->addrlen == sizeof (struct sockaddr_in6)) { in6 = (struct sockaddr_in6 *) &pos[1]; if ((addrlen == sizeof (struct in6_addr)) && (0 == memcmp (&in6->sin6_addr, addr, sizeof (struct in6_addr)))) return GNUNET_YES; } else { GNUNET_assert (0); } pos = pos->next; } LOG (GNUNET_ERROR_TYPE_WARNING, "Asked to validate one of my addresses and validation failed!\n"); return GNUNET_NO; } /* end of nat.c */