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3 Copyright (C) 2009, 2015, 2016 GNUnet e.V.
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6 under the terms of the GNU Affero General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
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13 Affero General Public License for more details.
16 * This code provides some support for doing STUN transactions.
17 * We send simplest possible packet ia REQUEST with BIND to a STUN server.
19 * All STUN packets start with a simple header made of a type,
20 * length (excluding the header) and a 16-byte random transaction id.
21 * Following the header we may have zero or more attributes, each
22 * structured as a type, length and a value (whose format depends
23 * on the type, but often contains addresses).
24 * Of course all fields are in network format.
26 * This code was based on ministun.c.
28 * @file nat/nat_api_stun.c
29 * @brief Functions for STUN functionality
30 * @author Bruno Souza Cabral
34 #include "gnunet_util_lib.h"
35 #include "gnunet_resolver_service.h"
36 #include "gnunet_nat_service.h"
41 #define LOG(kind,...) GNUNET_log_from (kind, "stun", __VA_ARGS__)
43 #define TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 15)
47 * Handle to a request given to the resolver. Can be used to cancel
48 * the request prior to the timeout or successful execution. Also
49 * used to track our internal state for the request.
51 struct GNUNET_NAT_STUN_Handle
55 * Handle to a pending DNS lookup request.
57 struct GNUNET_RESOLVER_RequestHandle *dns_active;
60 * Handle to the listen socket
62 struct GNUNET_NETWORK_Handle *sock;
70 * Function to call when a error occours
72 GNUNET_NAT_TestCallback cb;
80 * Do we got a DNS resolution successfully?
93 * Encode a class and method to a compatible STUN format
95 * @param msg_class class to be converted
96 * @param method method to be converted
97 * @return message in a STUN compatible format
100 encode_message (enum StunClasses msg_class,
101 enum StunMethods method)
103 return ((msg_class & 1) << 4) | ((msg_class & 2) << 7) |
104 (method & 0x000f) | ((method & 0x0070) << 1) | ((method & 0x0f800) << 2);
109 * Fill the stun_header with a random request_id
111 * @param req, stun header to be filled
114 generate_request_id (struct stun_header *req)
116 req->magic = htonl(STUN_MAGIC_COOKIE);
117 for (unsigned int x = 0; x < 3; x++)
118 req->id.id[x] = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
124 * Try to establish a connection given the specified address.
126 * @param cls our `struct GNUNET_NAT_STUN_Handle *`
127 * @param addr address to try, NULL for "last call"
128 * @param addrlen length of @a addr
131 stun_dns_callback (void *cls,
132 const struct sockaddr *addr,
135 struct GNUNET_NAT_STUN_Handle *rh = cls;
136 struct stun_header req;
137 struct sockaddr_in server;
141 rh->dns_active = NULL;
142 if (GNUNET_NO == rh->dns_success)
144 LOG (GNUNET_ERROR_TYPE_INFO,
145 "Error resolving host %s\n",
148 GNUNET_NAT_ERROR_NOT_ONLINE);
150 else if (GNUNET_SYSERR == rh->dns_success)
153 GNUNET_NAT_ERROR_INTERNAL_NETWORK_ERROR);
158 GNUNET_NAT_ERROR_SUCCESS);
160 GNUNET_NAT_stun_make_request_cancel (rh);
164 rh->dns_success = GNUNET_YES;
165 memset (&server, 0, sizeof(server));
166 server.sin_family = AF_INET;
167 server.sin_addr = ((struct sockaddr_in *)addr)->sin_addr;
168 server.sin_port = htons (rh->stun_port);
169 #if HAVE_SOCKADDR_IN_SIN_LEN
170 server.sin_len = (u_char) sizeof (struct sockaddr_in);
173 /* Craft the simplest possible STUN packet. A request binding */
174 generate_request_id (&req);
175 req.msglen = htons (0);
176 req.msgtype = htons (encode_message (STUN_REQUEST,
179 /* Send the packet */
181 GNUNET_NETWORK_socket_sendto (rh->sock,
184 (const struct sockaddr *) &server,
187 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
189 rh->dns_success = GNUNET_SYSERR;
196 * Make Generic STUN request. Sends a generic stun request to the
197 * server specified using the specified socket.
199 * @param server the address of the stun server
200 * @param port port of the stun server, in host byte order
201 * @param sock the socket used to send the request
202 * @param cb callback in case of error
203 * @param cb_cls closure for @a cb
204 * @return NULL on error
206 struct GNUNET_NAT_STUN_Handle *
207 GNUNET_NAT_stun_make_request (const char *server,
209 struct GNUNET_NETWORK_Handle *sock,
210 GNUNET_NAT_TestCallback cb,
213 struct GNUNET_NAT_STUN_Handle *rh;
215 rh = GNUNET_new (struct GNUNET_NAT_STUN_Handle);
219 rh->stun_server = GNUNET_strdup (server);
220 rh->stun_port = port;
221 rh->dns_success = GNUNET_NO;
222 rh->dns_active = GNUNET_RESOLVER_ip_get (rh->stun_server,
227 if (NULL == rh->dns_active)
229 GNUNET_NAT_stun_make_request_cancel (rh);
237 * Cancel active STUN request. Frees associated resources
238 * and ensures that the callback is no longer invoked.
240 * @param rh request to cancel
243 GNUNET_NAT_stun_make_request_cancel (struct GNUNET_NAT_STUN_Handle *rh)
245 if (NULL != rh->dns_active)
247 GNUNET_RESOLVER_request_cancel (rh->dns_active);
248 rh->dns_active = NULL;
250 GNUNET_free (rh->stun_server);
255 /* end of nat_stun.c */