/* This file is part of GNUnet. (C) 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_mini.c * @brief functions for interaction with miniupnp; tested with miniupnpc 1.5 * @author Christian Grothoff */ #include "platform.h" #include "gnunet_util_lib.h" #include "gnunet_nat_lib.h" #include "nat.h" #define LOG(kind,...) GNUNET_log_from (kind, "nat", __VA_ARGS__) /** * How long do we give upnpc to create a mapping? */ #define MAP_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 15) /** * How long do we give upnpc to remove a mapping? */ #define UNMAP_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1) /** * How often do we check for changes in the mapping? */ #define MAP_REFRESH_FREQ GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 5) /** * Opaque handle to cancel "GNUNET_NAT_mini_get_external_ipv4" operation. */ struct GNUNET_NAT_ExternalHandle { /** * Function to call with the result. */ GNUNET_NAT_IPCallback cb; /** * Closure for 'cb'. */ void *cb_cls; /** * Read task. */ GNUNET_SCHEDULER_TaskIdentifier task; /** * Handle to 'external-ip' process. */ struct GNUNET_OS_Process *eip; /** * Handle to stdout pipe of 'external-ip'. */ struct GNUNET_DISK_PipeHandle *opipe; /** * Read handle of 'opipe'. */ const struct GNUNET_DISK_FileHandle *r; /** * When should this operation time out? */ struct GNUNET_TIME_Absolute timeout; /** * Number of bytes in 'buf' that are valid. */ size_t off; /** * Destination of our read operation (output of 'external-ip'). */ char buf[17]; }; /** * Read the output of 'external-ip' into buf. When complete, parse the * address and call our callback. * * @param cls the 'struct GNUNET_NAT_ExternalHandle' * @param tc scheduler context */ static void read_external_ipv4 (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_NAT_ExternalHandle *eh = cls; ssize_t ret; struct in_addr addr; int iret; eh->task = GNUNET_SCHEDULER_NO_TASK; if (GNUNET_YES == GNUNET_NETWORK_fdset_handle_isset (tc->read_ready, eh->r)) ret = GNUNET_DISK_file_read (eh->r, &eh->buf[eh->off], sizeof (eh->buf) - eh->off); else ret = -1; /* error reading, timeout, etc. */ if (ret > 0) { /* try to read more */ eh->off += ret; eh->task = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_absolute_get_remaining (eh->timeout), eh->r, &read_external_ipv4, eh); return; } iret = GNUNET_NO; if ((eh->off > 7) && (eh->buf[eh->off - 1] == '\n')) { eh->buf[eh->off - 1] = '\0'; if (1 == inet_pton (AF_INET, eh->buf, &addr)) { if (addr.s_addr == 0) iret = GNUNET_NO; /* got 0.0.0.0 */ else iret = GNUNET_OK; } } eh->cb (eh->cb_cls, (iret == GNUNET_OK) ? &addr : NULL); GNUNET_NAT_mini_get_external_ipv4_cancel (eh); } /** * Try to get the external IPv4 address of this peer. * * @param timeout when to fail * @param cb function to call with result * @param cb_cls closure for 'cb' * @return handle for cancellation (can only be used until 'cb' is called), NULL on error */ struct GNUNET_NAT_ExternalHandle * GNUNET_NAT_mini_get_external_ipv4 (struct GNUNET_TIME_Relative timeout, GNUNET_NAT_IPCallback cb, void *cb_cls) { struct GNUNET_NAT_ExternalHandle *eh; if (GNUNET_SYSERR == GNUNET_OS_check_helper_binary ("external-ip")) return NULL; eh = GNUNET_malloc (sizeof (struct GNUNET_NAT_ExternalHandle)); eh->cb = cb; eh->cb_cls = cb_cls; eh->opipe = GNUNET_DISK_pipe (GNUNET_YES, GNUNET_YES, GNUNET_NO, GNUNET_YES); if (NULL == eh->opipe) { GNUNET_free (eh); return NULL; } eh->eip = GNUNET_OS_start_process (GNUNET_NO, NULL, eh->opipe, "external-ip", "external-ip", NULL); if (NULL == eh->eip) { GNUNET_DISK_pipe_close (eh->opipe); GNUNET_free (eh); return NULL; } GNUNET_DISK_pipe_close_end (eh->opipe, GNUNET_DISK_PIPE_END_WRITE); eh->timeout = GNUNET_TIME_relative_to_absolute (timeout); eh->r = GNUNET_DISK_pipe_handle (eh->opipe, GNUNET_DISK_PIPE_END_READ); eh->task = GNUNET_SCHEDULER_add_read_file (timeout, eh->r, &read_external_ipv4, eh); return eh; } /** * Cancel operation. * * @param eh operation to cancel */ void GNUNET_NAT_mini_get_external_ipv4_cancel (struct GNUNET_NAT_ExternalHandle *eh) { (void) GNUNET_OS_process_kill (eh->eip, SIGKILL); GNUNET_OS_process_close (eh->eip); GNUNET_DISK_pipe_close (eh->opipe); if (GNUNET_SCHEDULER_NO_TASK != eh->task) GNUNET_SCHEDULER_cancel (eh->task); GNUNET_free (eh); } /** * Handle to a mapping created with upnpc. */ struct GNUNET_NAT_MiniHandle { /** * Function to call on mapping changes. */ GNUNET_NAT_AddressCallback ac; /** * Closure for 'ac'. */ void *ac_cls; /** * Command used to install the map. */ struct GNUNET_OS_CommandHandle *map_cmd; /** * Command used to refresh our map information. */ struct GNUNET_OS_CommandHandle *refresh_cmd; /** * Command used to remove the mapping. */ struct GNUNET_OS_CommandHandle *unmap_cmd; /** * Our current external mapping (if we have one). */ struct sockaddr_in current_addr; /** * We check the mapping periodically to see if it * still works. This task triggers the check. */ GNUNET_SCHEDULER_TaskIdentifier refresh_task; /** * Are we mapping TCP or UDP? */ int is_tcp; /** * Did we succeed with creating a mapping? */ int did_map; /** * Did we find our mapping during refresh scan? */ int found; /** * Which port are we mapping? */ uint16_t port; }; /** * Run upnpc -l to find out if our mapping changed. * * @param cls the 'struct GNUNET_NAT_MiniHandle' * @param tc scheduler context */ static void do_refresh (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc); /** * Process the output from the 'upnpc -r' command. * * @param cls the 'struct GNUNET_NAT_MiniHandle' * @param line line of output, NULL at the end */ static void process_map_output (void *cls, const char *line); /** * Process the output from 'upnpc -l' to see if our * external mapping changed. If so, do the notifications. * * @param cls the 'struct GNUNET_NAT_MiniHandle' * @param line line of output, NULL at the end */ static void process_refresh_output (void *cls, const char *line) { struct GNUNET_NAT_MiniHandle *mini = cls; char pstr[9]; const char *s; unsigned int nport; struct in_addr exip; if (NULL == line) { GNUNET_OS_command_stop (mini->refresh_cmd); mini->refresh_cmd = NULL; if (mini->found == GNUNET_NO) { /* mapping disappeared, try to re-create */ if (mini->did_map) { mini->ac (mini->ac_cls, GNUNET_NO, (const struct sockaddr *) &mini->current_addr, sizeof (mini->current_addr)); mini->did_map = GNUNET_NO; } GNUNET_snprintf (pstr, sizeof (pstr), "%u", (unsigned int) mini->port); mini->map_cmd = GNUNET_OS_command_run (&process_map_output, mini, MAP_TIMEOUT, "upnpc", "upnpc", "-r", pstr, mini->is_tcp ? "tcp" : "udp", NULL); if (NULL != mini->map_cmd) return; } mini->refresh_task = GNUNET_SCHEDULER_add_delayed (MAP_REFRESH_FREQ, &do_refresh, mini); return; } if (!mini->did_map) return; /* never mapped, won't find our mapping anyway */ /* we're looking for output of the form: * "ExternalIPAddress = 12.134.41.124" */ s = strstr (line, "ExternalIPAddress = "); if (NULL != s) { s += strlen ("ExternalIPAddress = "); if (1 != inet_pton (AF_INET, s, &exip)) return; /* skip */ if (exip.s_addr == mini->current_addr.sin_addr.s_addr) return; /* no change */ /* update mapping */ mini->ac (mini->ac_cls, GNUNET_NO, (const struct sockaddr *) &mini->current_addr, sizeof (mini->current_addr)); mini->current_addr.sin_addr = exip; mini->ac (mini->ac_cls, GNUNET_YES, (const struct sockaddr *) &mini->current_addr, sizeof (mini->current_addr)); return; } /* * we're looking for output of the form: * * "0 TCP 3000->192.168.2.150:3000 'libminiupnpc' ''" * "1 UDP 3001->192.168.2.150:3001 'libminiupnpc' ''" * * the pattern we look for is: * * "%s TCP PORT->STRING:OURPORT *" or * "%s UDP PORT->STRING:OURPORT *" */ GNUNET_snprintf (pstr, sizeof (pstr), ":%u ", mini->port); if (NULL == (s = strstr (line, "->"))) return; /* skip */ if (NULL == strstr (s, pstr)) return; /* skip */ if (1 != sscanf (line, (mini->is_tcp) ? "%*u TCP %u->%*s:%*u %*s" : "%*u UDP %u->%*s:%*u %*s", &nport)) return; /* skip */ mini->found = GNUNET_YES; if (nport == ntohs (mini->current_addr.sin_port)) return; /* no change */ /* external port changed, update mapping */ mini->ac (mini->ac_cls, GNUNET_NO, (const struct sockaddr *) &mini->current_addr, sizeof (mini->current_addr)); mini->current_addr.sin_port = htons ((uint16_t) nport); mini->ac (mini->ac_cls, GNUNET_YES, (const struct sockaddr *) &mini->current_addr, sizeof (mini->current_addr)); } /** * Run upnpc -l to find out if our mapping changed. * * @param cls the 'struct GNUNET_NAT_MiniHandle' * @param tc scheduler context */ static void do_refresh (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_NAT_MiniHandle *mini = cls; mini->refresh_task = GNUNET_SCHEDULER_NO_TASK; mini->found = GNUNET_NO; mini->refresh_cmd = GNUNET_OS_command_run (&process_refresh_output, mini, MAP_TIMEOUT, "upnpc", "upnpc", "-l", NULL); } /** * Process the output from the 'upnpc -r' command. * * @param cls the 'struct GNUNET_NAT_MiniHandle' * @param line line of output, NULL at the end */ static void process_map_output (void *cls, const char *line) { struct GNUNET_NAT_MiniHandle *mini = cls; const char *ipaddr; char *ipa; const char *pstr; unsigned int port; if (NULL == line) { GNUNET_OS_command_stop (mini->map_cmd); mini->map_cmd = NULL; mini->refresh_task = GNUNET_SCHEDULER_add_delayed (MAP_REFRESH_FREQ, &do_refresh, mini); return; } /* * The upnpc output we're after looks like this: * * "external 87.123.42.204:3000 TCP is redirected to internal 192.168.2.150:3000" */ if ((NULL == (ipaddr = strstr (line, " "))) || (NULL == (pstr = strstr (ipaddr, ":"))) || (1 != sscanf (pstr + 1, "%u", &port))) { return; /* skip line */ } ipa = GNUNET_strdup (ipaddr + 1); strstr (ipa, ":")[0] = '\0'; if (1 != inet_pton (AF_INET, ipa, &mini->current_addr.sin_addr)) { GNUNET_free (ipa); return; /* skip line */ } GNUNET_free (ipa); mini->current_addr.sin_port = htons (port); mini->current_addr.sin_family = AF_INET; #if HAVE_SOCKADDR_IN_SIN_LEN mini->current_addr.sin_len = sizeof (struct sockaddr_in); #endif mini->did_map = GNUNET_YES; mini->ac (mini->ac_cls, GNUNET_YES, (const struct sockaddr *) &mini->current_addr, sizeof (mini->current_addr)); } /** * Start mapping the given port using (mini)upnpc. This function * should typically not be used directly (it is used within the * general-purpose 'GNUNET_NAT_register' code). However, it can be * used if specifically UPnP-based NAT traversal is to be used or * tested. * * @param port port to map * @param is_tcp GNUNET_YES to map TCP, GNUNET_NO for UDP * @param ac function to call with mapping result * @param ac_cls closure for 'ac' * @return NULL on error (no 'upnpc' installed) */ struct GNUNET_NAT_MiniHandle * GNUNET_NAT_mini_map_start (uint16_t port, int is_tcp, GNUNET_NAT_AddressCallback ac, void *ac_cls) { struct GNUNET_NAT_MiniHandle *ret; char pstr[6]; if (GNUNET_SYSERR == GNUNET_OS_check_helper_binary ("upnpc")) return NULL; ret = GNUNET_malloc (sizeof (struct GNUNET_NAT_MiniHandle)); ret->ac = ac; ret->ac_cls = ac_cls; ret->is_tcp = is_tcp; ret->port = port; GNUNET_snprintf (pstr, sizeof (pstr), "%u", (unsigned int) port); ret->map_cmd = GNUNET_OS_command_run (&process_map_output, ret, MAP_TIMEOUT, "upnpc", "upnpc", "-r", pstr, is_tcp ? "tcp" : "udp", NULL); if (NULL != ret->map_cmd) return ret; ret->refresh_task = GNUNET_SCHEDULER_add_delayed (MAP_REFRESH_FREQ, &do_refresh, ret); return ret; } /** * Process output from our 'unmap' command. * * @param cls the 'struct GNUNET_NAT_MiniHandle' * @param line line of output, NULL at the end */ static void process_unmap_output (void *cls, const char *line) { struct GNUNET_NAT_MiniHandle *mini = cls; if (NULL == line) { #if DEBUG_NAT LOG (GNUNET_ERROR_TYPE_DEBUG, "UPnP unmap done\n"); #endif GNUNET_OS_command_stop (mini->unmap_cmd); mini->unmap_cmd = NULL; GNUNET_free (mini); return; } /* we don't really care about the output... */ } /** * Remove a mapping created with (mini)upnpc. Calling * this function will give 'upnpc' 1s to remove tha mapping, * so while this function is non-blocking, a task will be * left with the scheduler for up to 1s past this call. * * @param mini the handle */ void GNUNET_NAT_mini_map_stop (struct GNUNET_NAT_MiniHandle *mini) { char pstr[6]; if (GNUNET_SCHEDULER_NO_TASK != mini->refresh_task) { GNUNET_SCHEDULER_cancel (mini->refresh_task); mini->refresh_task = GNUNET_SCHEDULER_NO_TASK; } if (mini->refresh_cmd != NULL) { GNUNET_OS_command_stop (mini->refresh_cmd); mini->refresh_cmd = NULL; } if (!mini->did_map) { if (mini->map_cmd != NULL) { GNUNET_OS_command_stop (mini->map_cmd); mini->map_cmd = NULL; } GNUNET_free (mini); return; } mini->ac (mini->ac_cls, GNUNET_NO, (const struct sockaddr *) &mini->current_addr, sizeof (mini->current_addr)); /* Note: oddly enough, deletion uses the external port whereas * addition uses the internal port; this rarely matters since they * often are the same, but it might... */ GNUNET_snprintf (pstr, sizeof (pstr), "%u", (unsigned int) ntohs (mini->current_addr.sin_port)); #if DEBUG_NAT LOG (GNUNET_ERROR_TYPE_DEBUG, "Unmapping port %u with UPnP\n", ntohs (mini->current_addr.sin_port)); #endif mini->unmap_cmd = GNUNET_OS_command_run (&process_unmap_output, mini, UNMAP_TIMEOUT, "upnpc", "upnpc", "-d", pstr, mini->is_tcp ? "tcp" : "udp", NULL); } /* end of nat_mini.c */