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Diffstat (limited to 'src/nat/nat.c')
| -rw-r--r-- | src/nat/nat.c | 1411 |
1 files changed, 1411 insertions, 0 deletions
diff --git a/src/nat/nat.c b/src/nat/nat.c new file mode 100644 index 0000000..5117f5d --- /dev/null +++ b/src/nat/nat.c @@ -0,0 +1,1411 @@ +/* + 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); +#if DEBUG_NAT + LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding address `%s' from source %d\n", + GNUNET_a2s (arg, arg_size), src); +#endif + 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) + { +#if DEBUG_NAT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Finished reading from server stdout with code: %d\n", bytes); +#endif + 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_close (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); +#if DEBUG_NAT + LOG (GNUNET_ERROR_TYPE_DEBUG, "gnunet-helper-nat-server read: %s:%d\n", mybuf, + port); +#endif + 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)))) + { +#if DEBUG_NAT + LOG (GNUNET_ERROR_TYPE_DEBUG, "Starting `%s' at `%s'\n", + "gnunet-helper-nat-server", h->internal_address); +#endif + /* 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; + +#if DEBUG_NAT + 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); +#endif + 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_close (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). + * + * @param h NAT handle for us (largely used for configuration) + * @param sa the address of the peer (IPv4-only) + */ +void +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; /* 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_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_snprintf (port_as_string, sizeof (port_as_string), "%d", h->adv_port); +#if DEBUG_NAT + LOG (GNUNET_ERROR_TYPE_DEBUG, + _("Running gnunet-helper-nat-client %s %s %u\n"), h->internal_address, + inet4, (unsigned int) h->adv_port); +#endif + 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; + /* we know that the gnunet-helper-nat-client will terminate virtually + * instantly */ + GNUNET_OS_process_wait (proc); + GNUNET_OS_process_close (proc); +} + + +/** + * 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 */ |