/* This file is part of GNUnet (C) 2010 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 transport/plugin_transport_udp.c * @brief Implementation of the UDP NAT punching * transport service * @author Christian Grothoff * @author Nathan Evans * * The idea with this transport is to connect gnunet peers to each other * when ONE is behind a NAT. This is based on pwnat (http://samy.pl/pwnat) * created by Samy Kamkar. When configured with the PWNAT options, this * transport will start a server daemon which sends dummy ICMP and UDP * messages out to a predefined address (typically 1.2.3.4). * * When a non-NAT'd peer (the client) learns of the NAT'd peer (the server) * address, it will send ICMP RESPONSES to the NAT'd peers external address. * The NAT box should forward these faked responses to the server, which * can then connect directly to the non-NAT'd peer. */ #include "platform.h" #include "gnunet_hello_lib.h" #include "gnunet_connection_lib.h" #include "gnunet_container_lib.h" #include "gnunet_os_lib.h" #include "gnunet_peerinfo_service.h" #include "gnunet_protocols.h" #include "gnunet_resolver_service.h" #include "gnunet_server_lib.h" #include "gnunet_service_lib.h" #include "gnunet_signatures.h" #include "gnunet_statistics_service.h" #include "gnunet_transport_service.h" #include "plugin_transport.h" #include "transport.h" #define DEBUG_UDP GNUNET_YES #define MAX_PROBES 20 /* * Transport cost to peer, always 1 for UDP (direct connection) */ #define UDP_DIRECT_DISTANCE 1 #define DEFAULT_NAT_PORT 0 /** * How long until we give up on transmitting the welcome message? */ #define HOSTNAME_RESOLVE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5) /** * Starting port for listening and sending, eventually a config value */ #define UDP_NAT_DEFAULT_PORT 22086 /** * UDP Message-Packet header. */ struct UDPMessage { /** * Message header. */ struct GNUNET_MessageHeader header; /** * What is the identity of the sender (GNUNET_hash of public key) */ struct GNUNET_PeerIdentity sender; }; /** * Network format for IPv4 addresses. */ struct IPv4UdpAddress { /** * IPv4 address, in network byte order. */ uint32_t ipv4_addr GNUNET_PACKED; /** * Port number, in network byte order. */ uint16_t u_port GNUNET_PACKED; }; /** * Network format for IPv6 addresses. */ struct IPv6UdpAddress { /** * IPv6 address. */ struct in6_addr ipv6_addr GNUNET_PACKED; /** * Port number, in network byte order. */ uint16_t u6_port GNUNET_PACKED; }; /* Forward definition */ struct Plugin; struct PrettyPrinterContext { GNUNET_TRANSPORT_AddressStringCallback asc; void *asc_cls; uint16_t port; }; struct MessageQueue { /** * Linked List */ struct MessageQueue *next; /** * Session this message belongs to */ struct PeerSession *session; /** * Actual message to be sent */ char *msgbuf; /** * Size of message buffer to be sent */ size_t msgbuf_size; /** * When to discard this message */ struct GNUNET_TIME_Absolute timeout; /** * Continuation to call when this message goes out */ GNUNET_TRANSPORT_TransmitContinuation cont; /** * closure for continuation */ void *cont_cls; }; /** * UDP NAT Probe message definition */ struct UDP_NAT_ProbeMessage { /** * Message header */ struct GNUNET_MessageHeader header; }; /** * UDP NAT Probe message reply definition */ struct UDP_NAT_ProbeMessageReply { /** * Message header */ struct GNUNET_MessageHeader header; }; /** * UDP NAT Probe message confirm definition */ struct UDP_NAT_ProbeMessageConfirmation { /** * Message header */ struct GNUNET_MessageHeader header; }; /** * Local network addresses (actual IP address follows this struct). * PORT is NOT included! */ struct LocalAddrList { /** * This is a doubly linked list. */ struct LocalAddrList *next; /** * This is a doubly linked list. */ struct LocalAddrList *prev; /** * Number of bytes of the address that follow */ size_t size; }; /** * UDP NAT "Session" */ struct PeerSession { /** * Stored in a linked list. */ struct PeerSession *next; /** * Pointer to the global plugin struct. */ struct Plugin *plugin; /** * To whom are we talking to (set to our identity * if we are still waiting for the welcome message) */ struct GNUNET_PeerIdentity target; /** * Address of the other peer (either based on our 'connect' * call or on our 'accept' call). */ void *connect_addr; /** * Length of connect_addr. */ size_t connect_alen; /** * Are we still expecting the welcome message? (GNUNET_YES/GNUNET_NO) */ int expecting_welcome; /** * From which socket do we need to send to this peer? */ struct GNUNET_NETWORK_Handle *sock; /* * Queue of messages for this peer, in the case that * we have to await a connection... */ struct MessageQueue *messages; }; struct UDP_NAT_Probes { /** * Linked list */ struct UDP_NAT_Probes *next; /** * Address string that the server process returned to us */ char *address_string; /** * Timeout for this set of probes */ struct GNUNET_TIME_Absolute timeout; /** * Count of how many probes we've attempted */ int count; /** * The plugin this probe belongs to */ struct Plugin *plugin; /** * The task used to send these probes */ GNUNET_SCHEDULER_TaskIdentifier task; /** * Network address (always ipv4!) */ struct IPv4UdpAddress addr; }; /** * Encapsulation of all of the state of the plugin. */ struct Plugin { /** * Our environment. */ struct GNUNET_TRANSPORT_PluginEnvironment *env; /** * Handle to the network service. */ struct GNUNET_SERVICE_Context *service; /* * Session of peers with whom we are currently connected */ struct PeerSession *sessions; /** * Handle for request of hostname resolution, non-NULL if pending. */ struct GNUNET_RESOLVER_RequestHandle *hostname_dns; /** * ID of task used to update our addresses when one expires. */ GNUNET_SCHEDULER_TaskIdentifier address_update_task; /** * ID of select task */ GNUNET_SCHEDULER_TaskIdentifier select_task; /** * Port to listen on. */ uint16_t port; /** * The external address given to us by the user. Must be actual * outside visible address for NAT punching to work. */ char *external_address; /** * The internal address given to us by the user (or discovered). */ char *internal_address; /** * List of our IP addresses. */ struct LocalAddrList *lal_head; /** * Tail of our IP address list. */ struct LocalAddrList *lal_tail; /** * FD Read set */ struct GNUNET_NETWORK_FDSet *rs; /** * stdout pipe handle for the gnunet-nat-server process */ struct GNUNET_DISK_PipeHandle *server_stdout; /** * stdout file handle (for reading) for the gnunet-nat-server process */ const struct GNUNET_DISK_FileHandle *server_stdout_handle; /** * ID of select gnunet-nat-server stdout read task */ GNUNET_SCHEDULER_TaskIdentifier server_read_task; /** * Is this transport configured to be behind a NAT? */ int behind_nat; /** * Is this transport configured to allow connections to NAT'd peers? */ int allow_nat; /** * Should this transport advertise only NAT addresses (port set to 0)? * If not, all addresses will be duplicated for NAT punching and regular * ports. */ int only_nat_addresses; /** * The process id of the server process (if behind NAT) */ pid_t server_pid; /** * Probes in flight */ struct UDP_NAT_Probes *probes; }; struct UDP_Sock_Info { /* The network handle */ struct GNUNET_NETWORK_Handle *desc; /* The port we bound to */ int port; }; /* *********** globals ************* */ /** * the socket that we transmit all data with */ static struct UDP_Sock_Info udp_sock; /** * Forward declaration. */ void udp_probe_continuation (void *cls, const struct GNUNET_PeerIdentity *target, int result); /** * Disconnect from a remote node. Clean up session if we have one for this peer * * @param cls closure for this call (should be handle to Plugin) * @param target the peeridentity of the peer to disconnect * @return GNUNET_OK on success, GNUNET_SYSERR if the operation failed */ void udp_disconnect (void *cls, const struct GNUNET_PeerIdentity *target) { /** TODO: Implement! */ return; } /** * Shutdown the server process (stop receiving inbound traffic). Maybe * restarted later! * * @param cls Handle to the plugin for this transport * * @return returns the number of sockets successfully closed, * should equal the number of sockets successfully opened */ static int udp_transport_server_stop (void *cls) { struct Plugin *plugin = cls; int ret; int ok; ret = 0; if (plugin->select_task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (plugin->env->sched, plugin->select_task); plugin->select_task = GNUNET_SCHEDULER_NO_TASK; } ok = GNUNET_NETWORK_socket_close (udp_sock.desc); if (ok == GNUNET_OK) udp_sock.desc = NULL; ret += ok; if (plugin->behind_nat == GNUNET_YES) { if (0 != PLIBC_KILL (plugin->server_pid, SIGTERM)) { GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "kill"); } GNUNET_OS_process_wait (plugin->server_pid); } if (ret != GNUNET_OK) return GNUNET_SYSERR; return ret; } struct PeerSession * find_session (struct Plugin *plugin, const struct GNUNET_PeerIdentity *peer) { struct PeerSession *pos; pos = plugin->sessions; while (pos != NULL) { if (memcmp(&pos->target, peer, sizeof(struct GNUNET_PeerIdentity)) == 0) return pos; pos = pos->next; } return pos; } /** * Actually send out the message, assume we've got the address and * send_handle squared away! * * @param cls closure * @param send_handle which handle to send message on * @param target who should receive this message (ignored by UDP) * @param msgbuf one or more GNUNET_MessageHeader(s) strung together * @param msgbuf_size the size of the msgbuf to send * @param priority how important is the message (ignored by UDP) * @param timeout when should we time out (give up) if we can not transmit? * @param addr the addr to send the message to, needs to be a sockaddr for us * @param addrlen the len of addr * @param cont continuation to call once the message has * been transmitted (or if the transport is ready * for the next transmission call; or if the * peer disconnected...) * @param cont_cls closure for cont * @return the number of bytes written */ static ssize_t udp_real_send (void *cls, struct GNUNET_NETWORK_Handle *send_handle, const struct GNUNET_PeerIdentity *target, const char *msgbuf, size_t msgbuf_size, unsigned int priority, struct GNUNET_TIME_Relative timeout, const void *addr, size_t addrlen, GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls) { struct Plugin *plugin = cls; struct UDPMessage *message; int ssize; ssize_t sent; struct sockaddr_in a4; struct sockaddr_in6 a6; const struct IPv4UdpAddress *t4; const struct IPv6UdpAddress *t6; const void *sb; size_t sbs; if ((addr == NULL) || (addrlen == 0)) { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _ ("udp_real_send called without address, returning!\n")); #endif if (cont != NULL) cont (cont_cls, target, GNUNET_SYSERR); return 0; /* Can never send if we don't have an address!! */ } /* Build the message to be sent */ message = GNUNET_malloc (sizeof (struct UDPMessage) + msgbuf_size); ssize = sizeof (struct UDPMessage) + msgbuf_size; message->header.size = htons (ssize); message->header.type = htons (0); memcpy (&message->sender, plugin->env->my_identity, sizeof (struct GNUNET_PeerIdentity)); memcpy (&message[1], msgbuf, msgbuf_size); if (addrlen == sizeof (struct IPv6UdpAddress)) { t6 = addr; memset (&a6, 0, sizeof (a6)); #if HAVE_SOCKADDR_IN_SIN_LEN a6.sin6_len = sizeof (a6); #endif a6.sin6_family = AF_INET6; a6.sin6_port = t6->u6_port; memcpy (&a6.sin6_addr, &t6->ipv6_addr, sizeof (struct in6_addr)); sb = &a6; sbs = sizeof (a6); } else if (addrlen == sizeof (struct IPv4UdpAddress)) { t4 = addr; memset (&a4, 0, sizeof (a4)); #if HAVE_SOCKADDR_IN_SIN_LEN a4.sin_len = sizeof (a4); #endif a4.sin_family = AF_INET; a4.sin_port = t4->u_port; a4.sin_addr.s_addr = t4->ipv4_addr; sb = &a4; sbs = sizeof (a4); } else { GNUNET_break_op (0); GNUNET_free (message); return -1; } /* Actually send the message */ sent = GNUNET_NETWORK_socket_sendto (send_handle, message, ssize, sb, sbs); if (cont != NULL) { if (sent == GNUNET_SYSERR) cont (cont_cls, target, GNUNET_SYSERR); else { cont (cont_cls, target, GNUNET_OK); } } GNUNET_free (message); return sent; } /** * We learned about a peer (possibly behind NAT) so run the * gnunet-nat-client to send dummy ICMP responses * * @param plugin the plugin for this transport * @param addr the address of the peer * @param addrlen the length of the address */ void run_gnunet_nat_client (struct Plugin *plugin, const char *addr, size_t addrlen) { char addr_buf[INET_ADDRSTRLEN]; char *address_as_string; char *port_as_string; pid_t pid; const struct IPv4UdpAddress *t4; GNUNET_assert(addrlen == sizeof(struct IPv4UdpAddress)); t4 = (struct IPv4UdpAddress *)addr; if (NULL == inet_ntop (AF_INET, &t4->u_port, addr_buf, INET_ADDRSTRLEN)) { GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "inet_ntop"); return; } address_as_string = GNUNET_strdup (addr_buf); GNUNET_asprintf(&port_as_string, "%d", plugin->port); #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Running gnunet-nat-client with arguments: %s %s %d\n"), plugin->external_address, address_as_string, plugin->port); #endif /* Start the server process */ pid = GNUNET_OS_start_process(NULL, NULL, "gnunet-nat-client", "gnunet-nat-client", plugin->external_address, address_as_string, port_as_string, NULL); GNUNET_free(address_as_string); GNUNET_free(port_as_string); GNUNET_OS_process_wait (pid); } /** * Function that can be used by the transport service to transmit * a message using the plugin. * * @param cls closure * @param target who should receive this message (ignored by UDP) * @param msgbuf one or more GNUNET_MessageHeader(s) strung together * @param msgbuf_size the size of the msgbuf to send * @param priority how important is the message (ignored by UDP) * @param timeout when should we time out (give up) if we can not transmit? * @param session identifier used for this session (can be NULL) * @param addr the addr to send the message to, needs to be a sockaddr for us * @param addrlen the len of addr * @param force_address not used, we had better have an address to send to * because we are stateless!! * @param cont continuation to call once the message has * been transmitted (or if the transport is ready * for the next transmission call; or if the * peer disconnected...) * @param cont_cls closure for cont * * @return the number of bytes written (may return 0 and the message can * still be transmitted later!) */ static ssize_t udp_plugin_send (void *cls, const struct GNUNET_PeerIdentity *target, const char *msgbuf, size_t msgbuf_size, unsigned int priority, struct GNUNET_TIME_Relative timeout, struct Session *session, const void *addr, size_t addrlen, int force_address, GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls) { struct Plugin *plugin = cls; ssize_t sent; struct MessageQueue *temp_message; struct PeerSession *peer_session; int other_peer_natd; const struct IPv4UdpAddress *t4; GNUNET_assert (NULL == session); other_peer_natd = GNUNET_NO; if (addrlen == sizeof(struct IPv4UdpAddress)) { t4 = addr; if (ntohs(t4->u_port) == 0) other_peer_natd = GNUNET_YES; } else if (addrlen != sizeof(struct IPv6UdpAddress)) { GNUNET_break_op(0); return -1; /* Must have an address to send to */ } sent = 0; if ((other_peer_natd == GNUNET_YES) && (plugin->allow_nat == GNUNET_YES)) { peer_session = find_session(plugin, target); if (peer_session == NULL) /* We have a new peer to add */ { /* * The first time, we can assume we have no knowledge of a * working port for this peer, call the ICMP/UDP message sender * and wait... */ peer_session = GNUNET_malloc(sizeof(struct PeerSession)); peer_session->connect_addr = GNUNET_malloc(addrlen); memcpy(peer_session->connect_addr, addr, addrlen); peer_session->connect_alen = addrlen; peer_session->plugin = plugin; peer_session->sock = NULL; memcpy(&peer_session->target, target, sizeof(struct GNUNET_PeerIdentity)); peer_session->expecting_welcome = GNUNET_YES; peer_session->next = plugin->sessions; plugin->sessions = peer_session; peer_session->messages = GNUNET_malloc(sizeof(struct MessageQueue)); peer_session->messages->msgbuf = GNUNET_malloc(msgbuf_size); memcpy(peer_session->messages->msgbuf, msgbuf, msgbuf_size); peer_session->messages->msgbuf_size = msgbuf_size; peer_session->messages->timeout = GNUNET_TIME_relative_to_absolute(timeout); peer_session->messages->cont = cont; peer_session->messages->cont_cls = cont_cls; #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Other peer is NAT'd, set up peer session for peer %s\n"), GNUNET_i2s(target)); #endif run_gnunet_nat_client(plugin, addr, addrlen); } else { if (peer_session->expecting_welcome == GNUNET_NO) /* We are "connected" */ { sent = udp_real_send(cls, peer_session->sock, target, msgbuf, msgbuf_size, priority, timeout, peer_session->connect_addr, peer_session->connect_alen, cont, cont_cls); } else /* Haven't gotten a response from this peer, queue message */ { temp_message = GNUNET_malloc(sizeof(struct MessageQueue)); temp_message->msgbuf = GNUNET_malloc(msgbuf_size); memcpy(temp_message->msgbuf, msgbuf, msgbuf_size); temp_message->msgbuf_size = msgbuf_size; temp_message->timeout = GNUNET_TIME_relative_to_absolute(timeout); temp_message->cont = cont; temp_message->cont_cls = cont_cls; temp_message->next = peer_session->messages; peer_session->messages = temp_message; } } } else if (other_peer_natd == GNUNET_NO) /* Other peer not behind a NAT, so we can just send the message as is */ { sent = udp_real_send(cls, udp_sock.desc, target, msgbuf, msgbuf_size, priority, timeout, addr, addrlen, cont, cont_cls); } else /* Other peer is NAT'd, but we don't want to play with them (or can't!) */ return GNUNET_SYSERR; /* When GNUNET_SYSERR is returned from udp_real_send, we will still call * the callback so must not return GNUNET_SYSERR! * If we do, then transport context get freed twice. */ if (sent == GNUNET_SYSERR) return 0; return sent; } static void add_to_address_list (struct Plugin *plugin, const void *arg, size_t arg_size) { struct LocalAddrList *lal; lal = plugin->lal_head; while (NULL != lal) { if ( (lal->size == arg_size) && (0 == memcmp (&lal[1], arg, arg_size)) ) return; lal = lal->next; } lal = GNUNET_malloc (sizeof (struct LocalAddrList) + arg_size); lal->size = arg_size; memcpy (&lal[1], arg, arg_size); GNUNET_CONTAINER_DLL_insert (plugin->lal_head, plugin->lal_tail, lal); } static int check_local_addr (struct Plugin *plugin, const void *arg, size_t arg_size) { struct LocalAddrList *lal; lal = plugin->lal_head; while (NULL != lal) { if ( (lal->size == arg_size) && (0 == memcmp (&lal[1], arg, arg_size)) ) return GNUNET_OK; lal = lal->next; } return GNUNET_SYSERR; } /** * Add the IP of our network interface to the list of * our external IP addresses. */ static int process_interfaces (void *cls, const char *name, int isDefault, const struct sockaddr *addr, socklen_t addrlen) { struct Plugin *plugin = cls; int af; struct IPv4UdpAddress t4; struct IPv6UdpAddress t6; void *arg; uint16_t args; void *addr_nat; addr_nat = NULL; af = addr->sa_family; if (af == AF_INET) { t4.ipv4_addr = ((struct sockaddr_in *) addr)->sin_addr.s_addr; add_to_address_list (plugin, &t4.ipv4_addr, sizeof (uint32_t)); if ((plugin->behind_nat == GNUNET_YES) && (plugin->only_nat_addresses == GNUNET_YES)) { t4.u_port = htons (DEFAULT_NAT_PORT); } else if (plugin->behind_nat == GNUNET_YES) /* We are behind NAT, but will advertise NAT and normal addresses */ { addr_nat = GNUNET_malloc(sizeof(t4)); memcpy(addr_nat, &t4, sizeof(t4)); t4.u_port = plugin->port; ((struct IPv4UdpAddress *)addr_nat)->u_port = htons(DEFAULT_NAT_PORT); } else { t4.u_port = htons(plugin->port); } arg = &t4; args = sizeof (t4); } else if (af == AF_INET6) { if (IN6_IS_ADDR_LINKLOCAL (&((struct sockaddr_in6 *) addr)->sin6_addr)) { /* skip link local addresses */ return GNUNET_OK; } memcpy (&t6.ipv6_addr, &((struct sockaddr_in6 *) addr)->sin6_addr, sizeof (struct in6_addr)); add_to_address_list (plugin, &t6.ipv6_addr, sizeof (struct in6_addr)); if ((plugin->behind_nat == GNUNET_YES) && (plugin->only_nat_addresses == GNUNET_YES)) { t6.u6_port = htons (0); } else if (plugin->behind_nat == GNUNET_YES) { addr_nat = GNUNET_malloc(sizeof(t6)); memcpy(addr_nat, &t6, sizeof(t6)); t6.u6_port = plugin->port; ((struct IPv6UdpAddress *)addr_nat)->u6_port = htons(DEFAULT_NAT_PORT); } else { t6.u6_port = htons (plugin->port); } arg = &t6; args = sizeof (t6); } else { GNUNET_break (0); return GNUNET_OK; } GNUNET_log (GNUNET_ERROR_TYPE_INFO | GNUNET_ERROR_TYPE_BULK, _("Found address `%s' (%s)\n"), GNUNET_a2s (addr, addrlen), name); if (addr_nat != NULL) { plugin->env->notify_address (plugin->env->cls, "udp", addr_nat, args, GNUNET_TIME_UNIT_FOREVER_REL); GNUNET_log (GNUNET_ERROR_TYPE_INFO | GNUNET_ERROR_TYPE_BULK, _("Found NAT address `%s' (%s)\n"), GNUNET_a2s (addr_nat, args), name); GNUNET_free(addr_nat); } plugin->env->notify_address (plugin->env->cls, "udp", arg, args, GNUNET_TIME_UNIT_FOREVER_REL); return GNUNET_OK; } /** * Function called by the resolver for each address obtained from DNS * for our own hostname. Add the addresses to the list of our * external 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_ips (void *cls, const struct sockaddr *addr, socklen_t addrlen) { struct Plugin *plugin = cls; if (addr == NULL) { plugin->hostname_dns = NULL; return; } process_interfaces (plugin, "", GNUNET_YES, addr, addrlen); } /** * Send UDP probe messages or UDP keepalive messages, depending on the * state of the connection. * * @param cls closure for this call (should be the main Plugin) * @param tc task context for running this */ static void send_udp_probe_message (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct UDP_NAT_Probes *probe = cls; struct UDP_NAT_ProbeMessage *message; struct Plugin *plugin = probe->plugin; message = GNUNET_malloc(sizeof(struct UDP_NAT_ProbeMessage)); message->header.size = htons(sizeof(struct UDP_NAT_ProbeMessage)); message->header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_NAT_PROBE); /* If they gave us a port, use that. If not, try our port. */ if (ntohs(probe->addr.u_port) == 0) probe->addr.u_port = htons(plugin->port); #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Sending a probe to port %d\n"), ntohs(probe->addr.u_port)); #endif probe->count++; udp_real_send(plugin, udp_sock.desc, NULL, (char *)message, ntohs(message->header.size), 0, GNUNET_TIME_relative_get_unit(), &probe->addr, sizeof(probe->addr), &udp_probe_continuation, probe); GNUNET_free(message); } /** * Continuation for probe sends. If the last probe was sent * "successfully", schedule sending of another one. If not, * */ void udp_probe_continuation (void *cls, const struct GNUNET_PeerIdentity *target, int result) { struct UDP_NAT_Probes *probe = cls; struct Plugin *plugin = probe->plugin; if ((result == GNUNET_OK) && (probe->count < MAX_PROBES)) { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Scheduling next probe for 10000 milliseconds\n")); #endif probe->task = GNUNET_SCHEDULER_add_delayed(plugin->env->sched, GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MILLISECONDS, 10000), &send_udp_probe_message, probe); } else /* Destroy the probe context. */ { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Sending probe didn't go well...\n")); #endif } } /** * Find probe message by address * * @param plugin the plugin for this transport * @param address_string the ip address as a string */ struct UDP_NAT_Probes * find_probe(struct Plugin *plugin, char * address_string) { struct UDP_NAT_Probes *pos; pos = plugin->probes; while (pos != NULL) if (strcmp(pos->address_string, address_string) == 0) return pos; return pos; } /* * @param cls the plugin handle * @param tc the scheduling context (for rescheduling this function again) * * We have been notified that gnunet-nat-server has written something to stdout. * Handle the output, then reschedule this function to be called again once * more is available. * */ static void udp_plugin_server_read (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct Plugin *plugin = cls; char mybuf[40]; ssize_t bytes; memset(&mybuf, 0, sizeof(mybuf)); int i; struct UDP_NAT_Probes *temp_probe; int port; char *port_start; struct IPv4UdpAddress a4; if (tc->reason == GNUNET_SCHEDULER_REASON_SHUTDOWN) return; bytes = GNUNET_DISK_file_read(plugin->server_stdout_handle, &mybuf, sizeof(mybuf)); if (bytes < 1) { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Finished reading from server stdout with code: %d\n"), bytes); #endif return; } port = 0; port_start = NULL; for (i = 0; i < sizeof(mybuf); i++) { if (mybuf[i] == '\n') mybuf[i] = '\0'; if ((mybuf[i] == ':') && (i + 1 < sizeof(mybuf))) { mybuf[i] = '\0'; port_start = &mybuf[i + 1]; } } if (port_start != NULL) port = atoi(port_start); else { plugin->server_read_task = GNUNET_SCHEDULER_add_read_file (plugin->env->sched, GNUNET_TIME_UNIT_FOREVER_REL, plugin->server_stdout_handle, &udp_plugin_server_read, plugin); return; } #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("nat-server-read read: %s port %d\n"), &mybuf, port); #endif /** * We have received an ICMP response, ostensibly from a non-NAT'd peer * that wants to connect to us! Send a message to establish a connection. */ if (inet_pton(AF_INET, &mybuf[0], &a4.ipv4_addr) != 1) { GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _("nat-server-read malformed address\n"), &mybuf, port); plugin->server_read_task = GNUNET_SCHEDULER_add_read_file (plugin->env->sched, GNUNET_TIME_UNIT_FOREVER_REL, plugin->server_stdout_handle, &udp_plugin_server_read, plugin); return; } temp_probe = find_probe(plugin, &mybuf[0]); if (temp_probe == NULL) { temp_probe = GNUNET_malloc(sizeof(struct UDP_NAT_Probes)); temp_probe->address_string = strdup(&mybuf[0]); GNUNET_assert (1 == inet_pton(AF_INET, &mybuf[0], &temp_probe->addr.ipv4_addr)); temp_probe->addr.u_port = htons(port); temp_probe->next = plugin->probes; temp_probe->plugin = plugin; temp_probe->task = GNUNET_SCHEDULER_add_delayed(plugin->env->sched, GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MILLISECONDS, 500), &send_udp_probe_message, temp_probe); plugin->probes = temp_probe; } plugin->server_read_task = GNUNET_SCHEDULER_add_read_file (plugin->env->sched, GNUNET_TIME_UNIT_FOREVER_REL, plugin->server_stdout_handle, &udp_plugin_server_read, plugin); } /** * Demultiplexer for UDP NAT messages * * @param plugin the main plugin for this transport * @param sender from which peer the message was received * @param currhdr pointer to the header of the message * @param sender_addr the address from which the message was received * @param fromlen the length of the address * @param sockinfo which socket did we receive the message on */ static void udp_demultiplexer(struct Plugin *plugin, struct GNUNET_PeerIdentity *sender, const struct GNUNET_MessageHeader *currhdr, const void *sender_addr, size_t fromlen, struct UDP_Sock_Info *sockinfo) { struct UDP_NAT_ProbeMessageReply *outgoing_probe_reply; struct UDP_NAT_ProbeMessageConfirmation *outgoing_probe_confirmation; char addr_buf[INET_ADDRSTRLEN]; struct UDP_NAT_Probes *outgoing_probe; struct PeerSession *peer_session; struct MessageQueue *pending_message; struct MessageQueue *pending_message_temp; uint16_t incoming_port; if (memcmp(sender, plugin->env->my_identity, sizeof(struct GNUNET_PeerIdentity)) == 0) { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Received a message from myself, dropping!!!\n")); #endif return; } incoming_port = 0; GNUNET_assert(sender_addr != NULL); /* Can recvfrom have a NULL address? */ if (fromlen == sizeof(struct IPv4UdpAddress)) { incoming_port = ntohs(((struct IPv4UdpAddress *)sender_addr)->u_port); } else if (fromlen == sizeof(struct IPv6UdpAddress)) { incoming_port = ntohs(((struct IPv6UdpAddress *)sender_addr)->u6_port); } switch (ntohs(currhdr->type)) { case GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_NAT_PROBE: /* Send probe reply */ outgoing_probe_reply = GNUNET_malloc(sizeof(struct UDP_NAT_ProbeMessageReply)); outgoing_probe_reply->header.size = htons(sizeof(struct UDP_NAT_ProbeMessageReply)); outgoing_probe_reply->header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_NAT_PROBE_REPLY); #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Received a probe on listen port %d, sent_from port %d\n"), sockinfo->port, incoming_port); #endif udp_real_send(plugin, sockinfo->desc, NULL, (char *)outgoing_probe_reply, ntohs(outgoing_probe_reply->header.size), 0, GNUNET_TIME_relative_get_unit(), sender_addr, fromlen, NULL, NULL); #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Sent PROBE REPLY to port %d on outgoing port %d\n"), incoming_port, sockinfo->port); #endif GNUNET_free(outgoing_probe_reply); break; case GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_NAT_PROBE_REPLY: /* Check for existing probe, check ports returned, send confirmation if all is well */ #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Received PROBE REPLY from port %d on incoming port %d\n"), incoming_port, sockinfo->port); #endif if (sizeof(sender_addr) == sizeof(struct IPv4UdpAddress)) { memset(&addr_buf, 0, sizeof(addr_buf)); if (NULL == inet_ntop (AF_INET, &((struct IPv4UdpAddress *) sender_addr)->ipv4_addr, addr_buf, INET_ADDRSTRLEN)) { GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "inet_ntop"); return; } outgoing_probe = find_probe(plugin, &addr_buf[0]); if (outgoing_probe != NULL) { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Sending confirmation that we were reached!\n")); #endif outgoing_probe_confirmation = GNUNET_malloc(sizeof(struct UDP_NAT_ProbeMessageConfirmation)); outgoing_probe_confirmation->header.size = htons(sizeof(struct UDP_NAT_ProbeMessageConfirmation)); outgoing_probe_confirmation->header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_NAT_PROBE_CONFIRM); udp_real_send(plugin, sockinfo->desc, NULL, (char *)outgoing_probe_confirmation, ntohs(outgoing_probe_confirmation->header.size), 0, GNUNET_TIME_relative_get_unit(), sender_addr, fromlen, NULL, NULL); if (outgoing_probe->task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel(plugin->env->sched, outgoing_probe->task); outgoing_probe->task = GNUNET_SCHEDULER_NO_TASK; /* Schedule task to timeout and remove probe if confirmation not received */ } GNUNET_free(outgoing_probe_confirmation); } else { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _("Received a probe reply, but have no record of a sent probe!\n")); #endif } } break; case GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_NAT_PROBE_CONFIRM: peer_session = find_session(plugin, sender); #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Looking up peer session for peer %s\n"), GNUNET_i2s(sender)); #endif if (peer_session == NULL) /* Shouldn't this NOT happen? */ { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", _("Peer not in list, adding (THIS MAY BE A MISTAKE) %s\n"), GNUNET_i2s(sender)); #endif peer_session = GNUNET_malloc(sizeof(struct PeerSession)); peer_session->connect_addr = GNUNET_malloc(fromlen); memcpy(peer_session->connect_addr, sender_addr, fromlen); peer_session->connect_alen = fromlen; peer_session->plugin = plugin; peer_session->sock = sockinfo->desc; memcpy(&peer_session->target, sender, sizeof(struct GNUNET_PeerIdentity)); peer_session->expecting_welcome = GNUNET_NO; peer_session->next = plugin->sessions; plugin->sessions = peer_session; peer_session->messages = NULL; } else if (peer_session->expecting_welcome == GNUNET_YES) { peer_session->expecting_welcome = GNUNET_NO; peer_session->sock = sockinfo->desc; if (peer_session->connect_alen == sizeof(struct IPv4UdpAddress)) { ((struct IPv4UdpAddress *)peer_session->connect_addr)->u_port = htons(incoming_port); } else if (peer_session->connect_alen == sizeof(struct IPv4UdpAddress)) { ((struct IPv6UdpAddress *)peer_session->connect_addr)->u6_port = htons(incoming_port); } #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _("Received a probe confirmation, will send to peer on port %d\n"), incoming_port); #endif if (peer_session->messages != NULL) { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _("Received a probe confirmation, sending queued messages.\n")); #endif pending_message = peer_session->messages; int count = 0; while (pending_message != NULL) { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _("sending queued message %d\n"), count); #endif udp_real_send(plugin, peer_session->sock, &peer_session->target, pending_message->msgbuf, pending_message->msgbuf_size, 0, GNUNET_TIME_relative_get_unit(), peer_session->connect_addr, peer_session->connect_alen, pending_message->cont, pending_message->cont_cls); pending_message_temp = pending_message; pending_message = pending_message->next; GNUNET_free(pending_message_temp->msgbuf); GNUNET_free(pending_message_temp); #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _("finished sending queued message %d\n"), count); #endif count++; } } } else { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _("Received probe confirmation for already confirmed peer!\n")); #endif } /* Received confirmation, add peer with address/port specified */ break; case GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_NAT_PROBE_KEEPALIVE: /* Once we've sent NAT_PROBE_CONFIRM change to sending keepalives */ /* If we receive these just ignore! */ break; default: #if DEBUG_UDP GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _("Sending message type %d to transport!\n"), ntohs(currhdr->type)); #endif plugin->env->receive (plugin->env->cls, sender, currhdr, UDP_DIRECT_DISTANCE, NULL, sender_addr, fromlen); } } /* * @param cls the plugin handle * @param tc the scheduling context (for rescheduling this function again) * * We have been notified that our writeset has something to read. We don't * know which socket needs to be read, so we have to check each one * Then reschedule this function to be called again once more is available. * */ static void udp_plugin_select (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct Plugin *plugin = cls; char *buf; struct UDPMessage *msg; struct GNUNET_PeerIdentity *sender; unsigned int buflen; socklen_t fromlen; char addr[32]; ssize_t ret; int offset; int count; int tsize; char *msgbuf; const struct GNUNET_MessageHeader *currhdr; struct IPv4UdpAddress t4; struct IPv6UdpAddress t6; const struct sockaddr_in *s4; const struct sockaddr_in6 *s6; const void *ca; size_t calen; plugin->select_task = GNUNET_SCHEDULER_NO_TASK; if (tc->reason == GNUNET_SCHEDULER_REASON_SHUTDOWN) return; buf = NULL; sender = NULL; buflen = GNUNET_NETWORK_socket_recvfrom_amount (udp_sock.desc); if (buflen == GNUNET_NO) return; buf = GNUNET_malloc (buflen); fromlen = sizeof (addr); memset (&addr, 0, sizeof(addr)); ret = GNUNET_NETWORK_socket_recvfrom (udp_sock.desc, buf, buflen, (struct sockaddr *)&addr, &fromlen); if (AF_INET == ((struct sockaddr *)addr)->sa_family) { s4 = (const struct sockaddr_in*) &addr; t4.u_port = s4->sin_port; t4.ipv4_addr = s4->sin_addr.s_addr; ca = &t4; calen = sizeof (t4); } else if (AF_INET6 == ((struct sockaddr *)addr)->sa_family) { s6 = (const struct sockaddr_in6*) &addr; t6.u6_port = s6->sin6_port; memcpy (&t6.ipv6_addr, &s6->sin6_addr, sizeof (struct in6_addr)); ca = &t6; calen = sizeof (t6); } else { GNUNET_break (0); ca = NULL; calen = 0; } if (ret <= 0) { GNUNET_free (buf); return; } msg = (struct UDPMessage *) buf; if (ntohs (msg->header.size) < sizeof (struct UDPMessage)) { GNUNET_free (buf); return; } msgbuf = (char *)&msg[1]; sender = GNUNET_malloc (sizeof (struct GNUNET_PeerIdentity)); memcpy (sender, &msg->sender, sizeof (struct GNUNET_PeerIdentity)); offset = 0; count = 0; tsize = ntohs (msg->header.size) - sizeof(struct UDPMessage); while (offset < tsize) { currhdr = (struct GNUNET_MessageHeader *)&msgbuf[offset]; udp_demultiplexer(plugin, sender, currhdr, ca, calen, &udp_sock); offset += ntohs(currhdr->size); count++; } GNUNET_free_non_null (buf); GNUNET_free_non_null (sender); plugin->select_task = GNUNET_SCHEDULER_add_select (plugin->env->sched, GNUNET_SCHEDULER_PRIORITY_DEFAULT, GNUNET_SCHEDULER_NO_TASK, GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs, NULL, &udp_plugin_select, plugin); } /** * Create a slew of UDP sockets. If possible, use IPv6, otherwise * try IPv4. * * @param cls closure for server start, should be a struct Plugin * * * @return number of sockets created or GNUNET_SYSERR on error */ static int udp_transport_server_start (void *cls) { struct Plugin *plugin = cls; struct sockaddr_in serverAddrv4; struct sockaddr_in6 serverAddrv6; struct sockaddr *serverAddr; socklen_t addrlen; int sockets_created; sockets_created = 0; if (plugin->behind_nat == GNUNET_YES) { /* Pipe to read from started processes stdout (on read end) */ plugin->server_stdout = GNUNET_DISK_pipe(GNUNET_YES); if (plugin->server_stdout == NULL) return sockets_created; #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "Starting gnunet-nat-server process cmd: %s %s\n", "gnunet-nat-server", plugin->internal_address); #endif /* Start the server process */ plugin->server_pid = GNUNET_OS_start_process(NULL, plugin->server_stdout, "gnunet-nat-server", "gnunet-nat-server", plugin->internal_address, NULL); if (plugin->server_pid == GNUNET_SYSERR) { #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "Failed to start gnunet-nat-server process\n"); #endif return GNUNET_SYSERR; } /* Close the write end of the read pipe */ GNUNET_DISK_pipe_close_end(plugin->server_stdout, GNUNET_DISK_PIPE_END_WRITE); plugin->server_stdout_handle = GNUNET_DISK_pipe_handle(plugin->server_stdout, GNUNET_DISK_PIPE_END_READ); plugin->server_read_task = GNUNET_SCHEDULER_add_read_file (plugin->env->sched, GNUNET_TIME_UNIT_FOREVER_REL, plugin->server_stdout_handle, &udp_plugin_server_read, plugin); } udp_sock.desc = NULL; udp_sock.desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17); if (NULL == udp_sock.desc) { GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "socket"); return sockets_created; } else { memset (&serverAddrv4, 0, sizeof (serverAddrv4)); #if HAVE_SOCKADDR_IN_SIN_LEN serverAddrv4.sin_len = sizeof (serverAddrv4); #endif serverAddrv4.sin_family = AF_INET; serverAddrv4.sin_addr.s_addr = INADDR_ANY; serverAddrv4.sin_port = htons (plugin->port); addrlen = sizeof (serverAddrv4); serverAddr = (struct sockaddr *) &serverAddrv4; #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "Binding to port %d\n", ntohs(serverAddrv4.sin_port)); #endif while (GNUNET_NETWORK_socket_bind (udp_sock.desc, serverAddr, addrlen) != GNUNET_OK) { serverAddrv4.sin_port = htons (GNUNET_CRYPTO_random_u32(GNUNET_CRYPTO_QUALITY_STRONG, 33537) + 32000); /* Find a good, non-root port */ #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "Binding failed, trying new port %d\n", ntohs(serverAddrv4.sin_port)); #endif } udp_sock.port = ntohs(serverAddrv4.sin_port); sockets_created++; } if ((udp_sock.desc == NULL) && (GNUNET_YES != GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD", "DISABLE-IPV6"))) { udp_sock.desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17); if (udp_sock.desc != NULL) { memset (&serverAddrv6, 0, sizeof (serverAddrv6)); #if HAVE_SOCKADDR_IN_SIN_LEN serverAddrv6.sin6_len = sizeof (serverAddrv6); #endif serverAddrv6.sin6_family = AF_INET6; serverAddrv6.sin6_addr = in6addr_any; serverAddrv6.sin6_port = htons (plugin->port); addrlen = sizeof (serverAddrv6); serverAddr = (struct sockaddr *) &serverAddrv6; sockets_created++; } } plugin->rs = GNUNET_NETWORK_fdset_create (); GNUNET_NETWORK_fdset_zero (plugin->rs); GNUNET_NETWORK_fdset_set (plugin->rs, udp_sock.desc); plugin->select_task = GNUNET_SCHEDULER_add_select (plugin->env->sched, GNUNET_SCHEDULER_PRIORITY_DEFAULT, GNUNET_SCHEDULER_NO_TASK, GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs, NULL, &udp_plugin_select, plugin); return sockets_created; } /** * Check if the given port is plausible (must be either * our listen port or our advertised port). If it is * neither, we return GNUNET_SYSERR. * * @param plugin global variables * @param in_port port number to check * @return GNUNET_OK if port is either open_port or adv_port */ static int check_port (struct Plugin *plugin, uint16_t in_port) { if ( (plugin->behind_nat == GNUNET_YES) && (in_port == 0) ) return GNUNET_OK; if ( (plugin->only_nat_addresses == GNUNET_YES) && (plugin->behind_nat == GNUNET_YES) ) return GNUNET_SYSERR; /* odd case... */ if (in_port == plugin->port) return GNUNET_OK; return GNUNET_SYSERR; } /** * Function that will be called to check if a binary address for this * plugin is well-formed and corresponds to an address for THIS peer * (as per our configuration). Naturally, if absolutely necessary, * plugins can be a bit conservative in their answer, but in general * plugins should make sure that the address does not redirect * traffic to a 3rd party that might try to man-in-the-middle our * traffic. * * @param cls closure, should be our handle to the Plugin * @param addr pointer to the address * @param addrlen length of addr * @return GNUNET_OK if this is a plausible address for this peer * and transport, GNUNET_SYSERR if not * */ static int udp_check_address (void *cls, const void *addr, size_t addrlen) { struct Plugin *plugin = cls; char buf[INET6_ADDRSTRLEN]; const void *sb; struct in_addr a4; struct in6_addr a6; int af; uint16_t port; struct IPv4UdpAddress *v4; struct IPv6UdpAddress *v6; if ((addrlen != sizeof (struct IPv4UdpAddress)) && (addrlen != sizeof (struct IPv6UdpAddress))) { GNUNET_break_op (0); return GNUNET_SYSERR; } if (addrlen == sizeof (struct IPv4UdpAddress)) { v4 = (struct IPv4UdpAddress *) addr; if (GNUNET_OK != check_port (plugin, ntohs (v4->u_port))) return GNUNET_SYSERR; if (GNUNET_OK != check_local_addr (plugin, &v4->ipv4_addr, sizeof (uint32_t))) return GNUNET_SYSERR; af = AF_INET; port = ntohs (v4->u_port); memcpy (&a4, &v4->ipv4_addr, sizeof (a4)); sb = &a4; } else { v6 = (struct IPv6UdpAddress *) addr; if (IN6_IS_ADDR_LINKLOCAL (&v6->ipv6_addr)) { GNUNET_break_op (0); return GNUNET_SYSERR; } if (GNUNET_OK != check_port (plugin, ntohs (v6->u6_port))) return GNUNET_SYSERR; if (GNUNET_OK != check_local_addr (plugin, &v6->ipv6_addr, sizeof (struct in6_addr))) return GNUNET_SYSERR; af = AF_INET6; port = ntohs (v6->u6_port); memcpy (&a6, &v6->ipv6_addr, sizeof (a6)); sb = &a6; } inet_ntop (af, sb, buf, INET6_ADDRSTRLEN); #if DEBUG_UDP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "Informing transport service about my address `%s:%u'\n", buf, port); #endif return GNUNET_OK; } /** * Append our port and forward the result. */ static void append_port (void *cls, const char *hostname) { struct PrettyPrinterContext *ppc = cls; char *ret; if (hostname == NULL) { ppc->asc (ppc->asc_cls, NULL); GNUNET_free (ppc); return; } GNUNET_asprintf (&ret, "%s:%d", hostname, ppc->port); ppc->asc (ppc->asc_cls, ret); GNUNET_free (ret); } /** * Convert the transports address to a nice, human-readable * format. * * @param cls closure * @param type name of the transport that generated the address * @param addr one of the addresses of the host, NULL for the last address * the specific address format depends on the transport * @param addrlen length of the address * @param numeric should (IP) addresses be displayed in numeric form? * @param timeout after how long should we give up? * @param asc function to call on each string * @param asc_cls closure for asc */ static void udp_plugin_address_pretty_printer (void *cls, const char *type, const void *addr, size_t addrlen, int numeric, struct GNUNET_TIME_Relative timeout, GNUNET_TRANSPORT_AddressStringCallback asc, void *asc_cls) { struct Plugin *plugin = cls; const struct sockaddr_in *v4; const struct sockaddr_in6 *v6; struct PrettyPrinterContext *ppc; if ((addrlen != sizeof (struct sockaddr_in)) && (addrlen != sizeof (struct sockaddr_in6))) { /* invalid address */ GNUNET_break_op (0); asc (asc_cls, NULL); return; } ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext)); ppc->asc = asc; ppc->asc_cls = asc_cls; if (addrlen == sizeof (struct sockaddr_in)) { v4 = (const struct sockaddr_in *) addr; ppc->port = ntohs (v4->sin_port); } else { v6 = (const struct sockaddr_in6 *) addr; ppc->port = ntohs (v6->sin6_port); } GNUNET_RESOLVER_hostname_get (plugin->env->sched, plugin->env->cfg, addr, addrlen, !numeric, timeout, &append_port, ppc); } /** * Return the actual path to a file found in the current * PATH environment variable. * * @param binary the name of the file to find */ static char * get_path_from_PATH (char *binary) { char *path; char *pos; char *end; char *buf; const char *p; p = getenv ("PATH"); if (p == NULL) return NULL; path = GNUNET_strdup (p); /* because we write on it */ buf = GNUNET_malloc (strlen (path) + 20); pos = path; while (NULL != (end = strchr (pos, ':'))) { *end = '\0'; sprintf (buf, "%s/%s", pos, binary); if (GNUNET_DISK_file_test (buf) == GNUNET_YES) { GNUNET_free (path); return buf; } pos = end + 1; } sprintf (buf, "%s/%s", pos, binary); if (GNUNET_DISK_file_test (buf) == GNUNET_YES) { GNUNET_free (path); return buf; } GNUNET_free (buf); GNUNET_free (path); return NULL; } /** * Check whether the suid bit is set on a file. * Attempts to find the file using the current * PATH environment variable as a search path. * * @param binary the name of the file to check */ static int check_gnunet_nat_binary(char *binary) { struct stat statbuf; char *p; p = get_path_from_PATH (binary); if (p == NULL) return GNUNET_NO; if (0 != STAT (p, &statbuf)) { GNUNET_free (p); return GNUNET_SYSERR; } GNUNET_free (p); if ( (0 != (statbuf.st_mode & S_ISUID)) && (statbuf.st_uid == 0) ) return GNUNET_YES; return GNUNET_NO; } /** * Function called for a quick conversion of the binary address to * a numeric address. Note that the caller must not free the * address and that the next call to this function is allowed * to override the address again. * * @param cls closure * @param addr binary address * @param addrlen length of the address * @return string representing the same address */ static const char* udp_address_to_string (void *cls, const void *addr, size_t addrlen) { static char rbuf[INET6_ADDRSTRLEN + 10]; char buf[INET6_ADDRSTRLEN]; const void *sb; struct in_addr a4; struct in6_addr a6; const struct IPv4UdpAddress *t4; const struct IPv6UdpAddress *t6; int af; uint16_t port; if (addrlen == sizeof (struct IPv6UdpAddress)) { t6 = addr; af = AF_INET6; port = ntohs (t6->u6_port); memcpy (&a6, &t6->ipv6_addr, sizeof (a6)); sb = &a6; } else if (addrlen == sizeof (struct IPv4UdpAddress)) { t4 = addr; af = AF_INET; port = ntohs (t4->u_port); memcpy (&a4, &t4->ipv4_addr, sizeof (a4)); sb = &a4; } else return NULL; inet_ntop (af, sb, buf, INET6_ADDRSTRLEN); GNUNET_snprintf (rbuf, sizeof (rbuf), "%s:%u", buf, port); return rbuf; } /** * The exported method. Makes the core api available via a global and * returns the udp transport API. */ void * libgnunet_plugin_transport_udp_init (void *cls) { struct GNUNET_TRANSPORT_PluginEnvironment *env = cls; unsigned long long mtu; unsigned long long port; struct GNUNET_TRANSPORT_PluginFunctions *api; struct Plugin *plugin; struct GNUNET_SERVICE_Context *service; int sockets_created; int behind_nat; int allow_nat; int only_nat_addresses; char *internal_address; char *external_address; struct IPv4UdpAddress v4_address; service = GNUNET_SERVICE_start ("transport-udp", env->sched, env->cfg); if (service == NULL) { GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _ ("Failed to start service for `%s' transport plugin.\n"), "udp"); return NULL; } if (GNUNET_YES == GNUNET_CONFIGURATION_get_value_yesno (env->cfg, "transport-udp", "BEHIND_NAT")) { /* We are behind nat (according to the user) */ if (check_gnunet_nat_binary("gnunet-nat-server") == GNUNET_YES) behind_nat = GNUNET_YES; else { behind_nat = GNUNET_NO; GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", "Configuration specified you are behind a NAT, but gnunet-nat-server is not installed properly (suid bit not set)!\n"); } } else behind_nat = GNUNET_NO; /* We are not behind nat! */ if (GNUNET_YES == GNUNET_CONFIGURATION_get_value_yesno (env->cfg, "transport-udp", "ALLOW_NAT")) { if (check_gnunet_nat_binary("gnunet-nat-client") == GNUNET_YES) allow_nat = GNUNET_YES; /* We will try to connect to NAT'd peers */ else { allow_nat = GNUNET_NO; GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", "Configuration specified you want to connect to NAT'd peers, but gnunet-nat-client is not installed properly (suid bit not set)!\n"); } } else allow_nat = GNUNET_NO; /* We don't want to try to help NAT'd peers */ if (GNUNET_YES == GNUNET_CONFIGURATION_get_value_yesno (env->cfg, "transport-udp", "ONLY_NAT_ADDRESSES")) only_nat_addresses = GNUNET_YES; /* We will only report our addresses as NAT'd */ else only_nat_addresses = GNUNET_NO; /* We will report our addresses as NAT'd and non-NAT'd */ external_address = NULL; if (((GNUNET_YES == behind_nat) || (GNUNET_YES == allow_nat)) && (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string (env->cfg, "transport-udp", "EXTERNAL_ADDRESS", &external_address))) { GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "udp", _ ("Require EXTERNAL_ADDRESS for service `%s' in configuration (either BEHIND_NAT or ALLOW_NAT set to YES)!\n"), "transport-udp"); GNUNET_SERVICE_stop (service); return NULL; } if ((external_address != NULL) && (inet_pton(AF_INET, external_address, &v4_address.ipv4_addr) != 1)) { GNUNET_log_from(GNUNET_ERROR_TYPE_WARNING, "udp", "Malformed EXTERNAL_ADDRESS %s given in configuration!\n", external_address); } internal_address = NULL; if ((GNUNET_YES == behind_nat) && (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string (env->cfg, "transport-udp", "INTERNAL_ADDRESS", &internal_address))) { GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "udp", _ ("Require INTERNAL_ADDRESS for service `%s' in configuration!\n"), "transport-udp"); GNUNET_SERVICE_stop (service); GNUNET_free_non_null(external_address); return NULL; } if ((internal_address != NULL) && (inet_pton(AF_INET, internal_address, &v4_address.ipv4_addr) != 1)) { GNUNET_log_from(GNUNET_ERROR_TYPE_WARNING, "udp", "Malformed INTERNAL_ADDRESS %s given in configuration!\n", internal_address); } if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_number (env->cfg, "transport-udp", "PORT", &port)) port = UDP_NAT_DEFAULT_PORT; else if (port > 65535) { GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _("Given `%s' option is out of range: %llu > %u\n"), "PORT", port, 65535); GNUNET_SERVICE_stop (service); GNUNET_free_non_null(external_address); GNUNET_free_non_null(internal_address); return NULL; } mtu = 1240; if (mtu < 1200) GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _("MTU %llu for `%s' is probably too low!\n"), mtu, "UDP"); plugin = GNUNET_malloc (sizeof (struct Plugin)); plugin->external_address = external_address; plugin->internal_address = internal_address; plugin->port = port; plugin->behind_nat = behind_nat; plugin->allow_nat = allow_nat; plugin->only_nat_addresses = only_nat_addresses; plugin->env = env; api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions)); api->cls = plugin; api->send = &udp_plugin_send; api->disconnect = &udp_disconnect; api->address_pretty_printer = &udp_plugin_address_pretty_printer; api->address_to_string = &udp_address_to_string; api->check_address = &udp_check_address; plugin->service = service; if (plugin->behind_nat == GNUNET_NO) { GNUNET_OS_network_interfaces_list (&process_interfaces, plugin); } plugin->hostname_dns = GNUNET_RESOLVER_hostname_resolve (env->sched, env->cfg, AF_UNSPEC, HOSTNAME_RESOLVE_TIMEOUT, &process_hostname_ips, plugin); if ((plugin->behind_nat == GNUNET_YES) && (inet_pton(AF_INET, plugin->external_address, &v4_address.ipv4_addr) == 1)) { v4_address.u_port = htons(0); plugin->env->notify_address (plugin->env->cls, "udp", &v4_address, sizeof(v4_address), GNUNET_TIME_UNIT_FOREVER_REL); } else if ((plugin->external_address != NULL) && (inet_pton(AF_INET, plugin->external_address, &v4_address.ipv4_addr) == 1)) { v4_address.u_port = htons(plugin->port); plugin->env->notify_address (plugin->env->cls, "udp", &v4_address, sizeof(v4_address), GNUNET_TIME_UNIT_FOREVER_REL); } sockets_created = udp_transport_server_start (plugin); GNUNET_assert (sockets_created == 1); return api; } void * libgnunet_plugin_transport_udp_done (void *cls) { struct GNUNET_TRANSPORT_PluginFunctions *api = cls; struct Plugin *plugin = api->cls; struct LocalAddrList *lal; udp_transport_server_stop (plugin); if (NULL != plugin->hostname_dns) { GNUNET_RESOLVER_request_cancel (plugin->hostname_dns); plugin->hostname_dns = NULL; } GNUNET_SERVICE_stop (plugin->service); GNUNET_NETWORK_fdset_destroy (plugin->rs); while (NULL != (lal = plugin->lal_head)) { GNUNET_CONTAINER_DLL_remove (plugin->lal_head, plugin->lal_tail, lal); GNUNET_free (lal); } GNUNET_free (plugin); GNUNET_free (api); return NULL; } /* end of plugin_transport_udp.c */