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13 Affero General Public License for more details.
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16 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 * This code provides some support for doing STUN transactions.
20 * We send simplest possible packet ia REQUEST with BIND to a STUN server.
22 * All STUN packets start with a simple header made of a type,
23 * length (excluding the header) and a 16-byte random transaction id.
24 * Following the header we may have zero or more attributes, each
25 * structured as a type, length and a value (whose format depends
26 * on the type, but often contains addresses).
27 * Of course all fields are in network format.
29 * This code was based on ministun.c.
31 * @file nat/nat_api_stun.c
32 * @brief Functions for STUN functionality
33 * @author Bruno Souza Cabral
37 #include "gnunet_util_lib.h"
38 #include "gnunet_resolver_service.h"
39 #include "gnunet_nat_service.h"
44 #define LOG(kind,...) GNUNET_log_from (kind, "stun", __VA_ARGS__)
46 #define TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 15)
50 * Handle to a request given to the resolver. Can be used to cancel
51 * the request prior to the timeout or successful execution. Also
52 * used to track our internal state for the request.
54 struct GNUNET_NAT_STUN_Handle
58 * Handle to a pending DNS lookup request.
60 struct GNUNET_RESOLVER_RequestHandle *dns_active;
63 * Handle to the listen socket
65 struct GNUNET_NETWORK_Handle *sock;
73 * Function to call when a error occours
75 GNUNET_NAT_TestCallback cb;
83 * Do we got a DNS resolution successfully?
96 * Encode a class and method to a compatible STUN format
98 * @param msg_class class to be converted
99 * @param method method to be converted
100 * @return message in a STUN compatible format
103 encode_message (enum StunClasses msg_class,
104 enum StunMethods method)
106 return ((msg_class & 1) << 4) | ((msg_class & 2) << 7) |
107 (method & 0x000f) | ((method & 0x0070) << 1) | ((method & 0x0f800) << 2);
112 * Fill the stun_header with a random request_id
114 * @param req, stun header to be filled
117 generate_request_id (struct stun_header *req)
119 req->magic = htonl(STUN_MAGIC_COOKIE);
120 for (unsigned int x = 0; x < 3; x++)
121 req->id.id[x] = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
127 * Try to establish a connection given the specified address.
129 * @param cls our `struct GNUNET_NAT_STUN_Handle *`
130 * @param addr address to try, NULL for "last call"
131 * @param addrlen length of @a addr
134 stun_dns_callback (void *cls,
135 const struct sockaddr *addr,
138 struct GNUNET_NAT_STUN_Handle *rh = cls;
139 struct stun_header req;
140 struct sockaddr_in server;
144 rh->dns_active = NULL;
145 if (GNUNET_NO == rh->dns_success)
147 LOG (GNUNET_ERROR_TYPE_INFO,
148 "Error resolving host %s\n",
151 GNUNET_NAT_ERROR_NOT_ONLINE);
153 else if (GNUNET_SYSERR == rh->dns_success)
156 GNUNET_NAT_ERROR_INTERNAL_NETWORK_ERROR);
161 GNUNET_NAT_ERROR_SUCCESS);
163 GNUNET_NAT_stun_make_request_cancel (rh);
167 rh->dns_success = GNUNET_YES;
168 memset (&server, 0, sizeof(server));
169 server.sin_family = AF_INET;
170 server.sin_addr = ((struct sockaddr_in *)addr)->sin_addr;
171 server.sin_port = htons (rh->stun_port);
172 #if HAVE_SOCKADDR_IN_SIN_LEN
173 server.sin_len = (u_char) sizeof (struct sockaddr_in);
176 /* Craft the simplest possible STUN packet. A request binding */
177 generate_request_id (&req);
178 req.msglen = htons (0);
179 req.msgtype = htons (encode_message (STUN_REQUEST,
182 /* Send the packet */
184 GNUNET_NETWORK_socket_sendto (rh->sock,
187 (const struct sockaddr *) &server,
190 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
192 rh->dns_success = GNUNET_SYSERR;
199 * Make Generic STUN request. Sends a generic stun request to the
200 * server specified using the specified socket.
202 * @param server the address of the stun server
203 * @param port port of the stun server, in host byte order
204 * @param sock the socket used to send the request
205 * @param cb callback in case of error
206 * @param cb_cls closure for @a cb
207 * @return NULL on error
209 struct GNUNET_NAT_STUN_Handle *
210 GNUNET_NAT_stun_make_request (const char *server,
212 struct GNUNET_NETWORK_Handle *sock,
213 GNUNET_NAT_TestCallback cb,
216 struct GNUNET_NAT_STUN_Handle *rh;
218 rh = GNUNET_new (struct GNUNET_NAT_STUN_Handle);
222 rh->stun_server = GNUNET_strdup (server);
223 rh->stun_port = port;
224 rh->dns_success = GNUNET_NO;
225 rh->dns_active = GNUNET_RESOLVER_ip_get (rh->stun_server,
230 if (NULL == rh->dns_active)
232 GNUNET_NAT_stun_make_request_cancel (rh);
240 * Cancel active STUN request. Frees associated resources
241 * and ensures that the callback is no longer invoked.
243 * @param rh request to cancel
246 GNUNET_NAT_stun_make_request_cancel (struct GNUNET_NAT_STUN_Handle *rh)
248 if (NULL != rh->dns_active)
250 GNUNET_RESOLVER_request_cancel (rh->dns_active);
251 rh->dns_active = NULL;
253 GNUNET_free (rh->stun_server);
258 /* end of nat_stun.c */