nbns_client.c
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1 /**
2  * @file nbns_client.c
3  * @brief NBNS client (NetBIOS Name Service)
4  *
5  * @section License
6  *
7  * SPDX-License-Identifier: GPL-2.0-or-later
8  *
9  * Copyright (C) 2010-2022 Oryx Embedded SARL. All rights reserved.
10  *
11  * This file is part of CycloneTCP Open.
12  *
13  * This program is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU General Public License
15  * as published by the Free Software Foundation; either version 2
16  * of the License, or (at your option) any later version.
17  *
18  * This program is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21  * GNU General Public License for more details.
22  *
23  * You should have received a copy of the GNU General Public License
24  * along with this program; if not, write to the Free Software Foundation,
25  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
26  *
27  * @author Oryx Embedded SARL (www.oryx-embedded.com)
28  * @version 2.2.0
29  **/
30 
31 //Switch to the appropriate trace level
32 #define TRACE_LEVEL NBNS_TRACE_LEVEL
33 
34 //Dependencies
35 #include "core/net.h"
36 #include "ipv4/ipv4_misc.h"
37 #include "netbios/nbns_client.h"
38 #include "netbios/nbns_common.h"
39 #include "dns/dns_debug.h"
40 #include "debug.h"
41 
42 //Check TCP/IP stack configuration
43 #if (NBNS_CLIENT_SUPPORT == ENABLED && IPV4_SUPPORT == ENABLED)
44 
45 
46 /**
47  * @brief Resolve a host name using NBNS
48  * @param[in] interface Underlying network interface
49  * @param[in] name Name of the host to be resolved
50  * @param[out] ipAddr IP address corresponding to the specified host name
51  **/
52 
54 {
55  error_t error;
56  DnsCacheEntry *entry;
57 
58 #if (NET_RTOS_SUPPORT == ENABLED)
59  systime_t delay;
60 
61  //Debug message
62  TRACE_INFO("Resolving host name %s (NBNS resolver)...\r\n", name);
63 #endif
64 
65  //Get exclusive access
67 
68  //Search the DNS cache for the specified host name
70 
71  //Check whether a matching entry has been found
72  if(entry)
73  {
74  //Host name already resolved?
75  if(entry->state == DNS_STATE_RESOLVED ||
76  entry->state == DNS_STATE_PERMANENT)
77  {
78  //Return the corresponding IP address
79  *ipAddr = entry->ipAddr;
80  //Successful host name resolution
81  error = NO_ERROR;
82  }
83  else
84  {
85  //Host name resolution is in progress
86  error = ERROR_IN_PROGRESS;
87  }
88  }
89  else
90  {
91  //If no entry exists, then create a new one
92  entry = dnsCreateEntry();
93 
94  //Record the host name whose IP address is unknown
95  osStrcpy(entry->name, name);
96 
97  //Initialize DNS cache entry
98  entry->type = HOST_TYPE_IPV4;
100  entry->interface = interface;
101 
102  //Initialize retransmission counter
104  //Send NBNS query
105  error = nbnsSendQuery(entry);
106 
107  //NBNS message successfully sent?
108  if(!error)
109  {
110  //Save the time at which the query message was sent
111  entry->timestamp = osGetSystemTime();
112  //Set timeout value
115  //Decrement retransmission counter
116  entry->retransmitCount--;
117 
118  //Switch state
119  entry->state = DNS_STATE_IN_PROGRESS;
120  //Host name resolution is in progress
121  error = ERROR_IN_PROGRESS;
122  }
123  }
124 
125  //Release exclusive access
127 
128 #if (NET_RTOS_SUPPORT == ENABLED)
129  //Set default polling interval
131 
132  //Wait the host name resolution to complete
133  while(error == ERROR_IN_PROGRESS)
134  {
135  //Wait until the next polling period
136  osDelayTask(delay);
137 
138  //Get exclusive access
140 
141  //Search the DNS cache for the specified host name
143 
144  //Check whether a matching entry has been found
145  if(entry)
146  {
147  //Host name successfully resolved?
148  if(entry->state == DNS_STATE_RESOLVED)
149  {
150  //Return the corresponding IP address
151  *ipAddr = entry->ipAddr;
152  //Successful host name resolution
153  error = NO_ERROR;
154  }
155  }
156  else
157  {
158  //Host name resolution failed
159  error = ERROR_FAILURE;
160  }
161 
162  //Release exclusive access
164 
165  //Backoff support for less aggressive polling
166  delay = MIN(delay * 2, DNS_CACHE_MAX_POLLING_INTERVAL);
167  }
168 
169  //Check status code
170  if(error)
171  {
172  //Failed to resolve host name
173  TRACE_INFO("Host name resolution failed!\r\n");
174  }
175  else
176  {
177  //Successful host name resolution
178  TRACE_INFO("Host name resolved to %s...\r\n", ipAddrToString(ipAddr, NULL));
179  }
180 #endif
181 
182  //Return status code
183  return error;
184 }
185 
186 
187 /**
188  * @brief Send a NBNS query message
189  * @param[in] entry Pointer to a valid DNS cache entry
190  * @return Error code
191  **/
192 
194 {
195  error_t error;
196  size_t length;
197  size_t offset;
198  NetBuffer *buffer;
200  DnsQuestion *dnsQuestion;
202  NetTxAncillary ancillary;
203 
204  //Allocate a memory buffer to hold the NBNS query message
205  buffer = udpAllocBuffer(DNS_MESSAGE_MAX_SIZE, &offset);
206  //Failed to allocate buffer?
207  if(buffer == NULL)
208  return ERROR_OUT_OF_MEMORY;
209 
210  //Point to the NBNS header
211  message = netBufferAt(buffer, offset);
212 
213  //Format NBNS query message
214  message->id = htons(entry->id);
215  message->qr = 0;
216  message->opcode = DNS_OPCODE_QUERY;
217  message->aa = 0;
218  message->tc = 0;
219  message->rd = 0;
220  message->ra = 0;
221  message->z = 0;
222  message->b = 1;
223  message->rcode = DNS_RCODE_NO_ERROR;
224 
225  //The NBNS query contains one question
226  message->qdcount = HTONS(1);
227  message->ancount = 0;
228  message->nscount = 0;
229  message->arcount = 0;
230 
231  //Length of the NBNS query message
232  length = sizeof(DnsHeader);
233 
234  //Encode the NetBIOS name
235  length += nbnsEncodeName(entry->name, message->questions);
236 
237  //Point to the corresponding question structure
238  dnsQuestion = DNS_GET_QUESTION(message, length);
239  //Fill in question structure
240  dnsQuestion->qtype = HTONS(DNS_RR_TYPE_NB);
241  dnsQuestion->qclass = HTONS(DNS_RR_CLASS_IN);
242 
243  //Update the length of the NBNS query message
244  length += sizeof(DnsQuestion);
245 
246  //Adjust the length of the multi-part buffer
247  netBufferSetLength(buffer, offset + length);
248 
249  //Debug message
250  TRACE_INFO("Sending NBNS message (%" PRIuSIZE " bytes)...\r\n", length);
251  //Dump message
253 
254  //The destination address is the broadcast address
255  destIpAddr.length = sizeof(Ipv4Addr);
256  ipv4GetBroadcastAddr(entry->interface, &destIpAddr.ipv4Addr);
257 
258  //Additional options can be passed to the stack along with the packet
259  ancillary = NET_DEFAULT_TX_ANCILLARY;
260 
261  //A request packet is always sent to the well known port 137
262  error = udpSendBuffer(entry->interface, NULL, NBNS_PORT, &destIpAddr,
263  NBNS_PORT, buffer, offset, &ancillary);
264 
265  //Free previously allocated memory
266  netBufferFree(buffer);
267 
268  //Return status code
269  return error;
270 }
271 
272 
273 /**
274  * @brief Process NBNS response message
275  * @param[in] interface Underlying network interface
276  * @param[in] pseudoHeader UDP pseudo header
277  * @param[in] udpHeader UDP header
278  * @param[in] message Pointer to the NBNS response message
279  * @param[in] length Length of the message
280  **/
281 
282 void nbnsProcessResponse(NetInterface *interface, const Ipv4PseudoHeader *pseudoHeader,
283  const UdpHeader *udpHeader, const NbnsHeader *message, size_t length)
284 {
285  uint_t i;
286  size_t pos;
287  DnsCacheEntry *entry;
288  DnsResourceRecord *record;
289  NbnsAddrEntry *addrEntry;
290 
291  //The NBNS response shall contain one answer
292  if(ntohs(message->qdcount) != 0 && ntohs(message->ancount) != 1)
293  return;
294 
295  //Parse NetBIOS name
296  pos = nbnsParseName(message, length, sizeof(DnsHeader), NULL);
297  //Invalid name?
298  if(!pos)
299  return;
300 
301  //Point to the associated resource record
302  record = DNS_GET_RESOURCE_RECORD(message, pos);
303  //Point to the resource data
304  pos += sizeof(DnsResourceRecord);
305 
306  //Make sure the resource record is valid
307  if(pos > length)
308  return;
309  if((pos + ntohs(record->rdlength)) > length)
310  return;
311 
312  //Check the class and the type of the resource record
313  if(ntohs(record->rclass) != DNS_RR_CLASS_IN)
314  return;
315  if(ntohs(record->rtype) != DNS_RR_TYPE_NB)
316  return;
317 
318  //Verify the length of the data field
319  if(ntohs(record->rdlength) < sizeof(NbnsAddrEntry))
320  return;
321 
322  //Loop through DNS cache entries
323  for(i = 0; i < DNS_CACHE_SIZE; i++)
324  {
325  //Point to the current entry
326  entry = &dnsCache[i];
327 
328  //NBNS name resolution in progress?
329  if(entry->state == DNS_STATE_IN_PROGRESS &&
330  entry->protocol == HOST_NAME_RESOLVER_NBNS &&
331  entry->type == HOST_TYPE_IPV4)
332  {
333  //Compare identifiers
334  if(entry->id == ntohs(message->id))
335  {
336  //Compare NetBIOS names
337  if(nbnsCompareName(message, length, sizeof(DnsHeader), entry->name))
338  {
339  //Point to the address entry array
340  addrEntry = (NbnsAddrEntry *) record->rdata;
341  //Copy the IPv4 address
342  entry->ipAddr.length = sizeof(Ipv4Addr);
343  entry->ipAddr.ipv4Addr = addrEntry->addr;
344 
345  //Save current time
346  entry->timestamp = osGetSystemTime();
347  //Save TTL value
348  entry->timeout = ntohl(record->ttl) * 1000;
349  //Limit the lifetime of the NBNS cache entries
350  entry->timeout = MIN(entry->timeout, NBNS_MAX_LIFETIME);
351 
352  //Host name successfully resolved
353  entry->state = DNS_STATE_RESOLVED;
354  }
355  }
356  }
357  }
358 }
359 
360 #endif
uint8_t length
Definition: coap_common.h:193
#define htons(value)
Definition: cpu_endian.h:413
@ DNS_STATE_PERMANENT
Definition: dns_cache.h:88
HostType type
IPv4 or IPv6 host?
Definition: dns_cache.h:99
__start_packed struct @2 DnsResourceRecord
Resource record format.
const NetTxAncillary NET_DEFAULT_TX_ANCILLARY
Definition: net_misc.c:71
#define netMutex
Definition: net_legacy.h:266
size_t nbnsParseName(const NbnsHeader *message, size_t length, size_t pos, char_t *dest)
Decode a NetBIOS name.
Definition: nbns_common.c:204
IP network address.
Definition: ip.h:79
__start_packed struct @0 UdpHeader
UDP header.
@ DNS_OPCODE_QUERY
Definition: dns_common.h:81
Structure describing a buffer that spans multiple chunks.
Definition: net_mem.h:89
systime_t timeout
Retransmission timeout.
Definition: dns_cache.h:108
void nbnsProcessResponse(NetInterface *interface, const Ipv4PseudoHeader *pseudoHeader, const UdpHeader *udpHeader, const NbnsHeader *message, size_t length)
Process NBNS response message.
Definition: nbns_client.c:282
__start_packed struct @0 DnsHeader
DNS message header.
char_t * ipAddrToString(const IpAddr *ipAddr, char_t *str)
Convert a binary IP address to a string representation.
Definition: ip.c:806
@ ERROR_OUT_OF_MEMORY
Definition: error.h:63
#define NBNS_MAX_LIFETIME
Definition: nbns_client.h:72
#define NBNS_CLIENT_MAX_RETRIES
Definition: nbns_client.h:51
HostnameResolver protocol
Name resolution protocol.
Definition: dns_cache.h:100
@ DNS_RR_CLASS_IN
Internet.
Definition: dns_common.h:110
char_t name[]
#define NBNS_PORT
Definition: nbns_common.h:46
IpAddr ipAddr
IP address.
Definition: dns_cache.h:106
uint32_t Ipv4Addr
IPv4 network address.
Definition: ipv4.h:261
error_t nbnsSendQuery(DnsCacheEntry *entry)
Send a NBNS query message.
Definition: nbns_client.c:193
uint16_t id
Identifier used to match queries and responses.
Definition: dns_cache.h:104
@ ERROR_IN_PROGRESS
Definition: error.h:212
Helper functions for IPv4.
@ DNS_RR_TYPE_NB
NetBIOS name service.
Definition: dns_common.h:134
__start_packed struct @0 NbnsHeader
NBNS message header.
error_t
Error codes.
Definition: error.h:43
#define DNS_GET_QUESTION(message, offset)
Definition: dns_common.h:63
char_t name[DNS_MAX_NAME_LEN+1]
Domain name.
Definition: dns_cache.h:105
systime_t timestamp
Time stamp to manage entry lifetime.
Definition: dns_cache.h:107
#define DNS_GET_RESOURCE_RECORD(message, offset)
Definition: dns_common.h:64
Definitions common to NBNS client and NBNS responder.
void * netBufferAt(const NetBuffer *buffer, size_t offset)
Returns a pointer to the data at the specified position.
Definition: net_mem.c:413
NBNS client (NetBIOS Name Service)
@ ERROR_FAILURE
Generic error code.
Definition: error.h:45
#define NBNS_CLIENT_INIT_TIMEOUT
Definition: nbns_client.h:58
#define NetInterface
Definition: net.h:36
void netBufferFree(NetBuffer *buffer)
Dispose a multi-part buffer.
Definition: net_mem.c:282
DNS cache entry.
Definition: dns_cache.h:97
error_t udpSendBuffer(NetInterface *interface, const IpAddr *srcIpAddr, uint16_t srcPort, const IpAddr *destIpAddr, uint16_t destPort, NetBuffer *buffer, size_t offset, NetTxAncillary *ancillary)
Send a UDP datagram.
Definition: udp.c:548
DnsCacheEntry * dnsCreateEntry(void)
Create a new entry in the DNS cache.
Definition: dns_cache.c:104
#define NetTxAncillary
Definition: net_misc.h:36
systime_t maxTimeout
Maximum retransmission timeout.
Definition: dns_cache.h:109
#define Ipv4PseudoHeader
Definition: ipv4.h:39
#define TRACE_INFO(...)
Definition: debug.h:95
void dnsDumpMessage(const DnsHeader *message, size_t length)
Dump DNS message for debugging purpose.
Definition: dns_debug.c:52
#define MIN(a, b)
Definition: os_port.h:62
NetBuffer * udpAllocBuffer(size_t length, size_t *offset)
Allocate a buffer to hold a UDP packet.
Definition: udp.c:808
size_t length
Definition: ip.h:80
@ HOST_TYPE_IPV4
Definition: socket.h:176
__start_packed struct @1 NbnsAddrEntry
NBNS address entry.
size_t nbnsEncodeName(const char_t *src, uint8_t *dest)
Encode a NetBIOS name.
Definition: nbns_common.c:152
#define DNS_CACHE_INIT_POLLING_INTERVAL
Definition: dns_cache.h:61
uint32_t systime_t
System time.
#define ntohs(value)
Definition: cpu_endian.h:421
char char_t
Definition: compiler_port.h:43
DnsCacheEntry * dnsFindEntry(NetInterface *interface, const char_t *name, HostType type, HostnameResolver protocol)
Search the DNS cache for a given domain name.
Definition: dns_cache.c:187
Ipv4Addr ipv4Addr
Definition: ip.h:84
#define HTONS(value)
Definition: cpu_endian.h:410
@ DNS_STATE_IN_PROGRESS
Definition: dns_cache.h:86
NetInterface * interface
Underlying network interface.
Definition: dns_cache.h:101
void osAcquireMutex(OsMutex *mutex)
Acquire ownership of the specified mutex object.
#define DNS_CACHE_SIZE
Definition: dns_cache.h:47
void osReleaseMutex(OsMutex *mutex)
Release ownership of the specified mutex object.
__start_packed struct @1 DnsQuestion
Question format.
@ DNS_STATE_RESOLVED
Definition: dns_cache.h:87
error_t ipv4GetBroadcastAddr(NetInterface *interface, Ipv4Addr *addr)
Get IPv4 broadcast address.
Definition: ipv4_misc.c:734
#define DNS_MESSAGE_MAX_SIZE
Definition: dns_common.h:45
@ HOST_NAME_RESOLVER_NBNS
Definition: socket.h:190
error_t netBufferSetLength(NetBuffer *buffer, size_t length)
Adjust the length of a multi-part buffer.
Definition: net_mem.c:320
uint8_t message[]
Definition: chap.h:152
void osDelayTask(systime_t delay)
Delay routine.
DnsCacheEntry dnsCache[DNS_CACHE_SIZE]
Definition: dns_cache.c:52
DnsState state
Entry state.
Definition: dns_cache.h:98
uint_t retransmitCount
Retransmission counter.
Definition: dns_cache.h:110
#define PRIuSIZE
unsigned int uint_t
Definition: compiler_port.h:45
TCP/IP stack core.
@ DNS_RCODE_NO_ERROR
Definition: dns_common.h:95
Data logging functions for debugging purpose (DNS)
#define osStrcpy(s1, s2)
Definition: os_port.h:197
#define DNS_CACHE_MAX_POLLING_INTERVAL
Definition: dns_cache.h:68
uint8_t ipAddr[4]
Definition: mib_common.h:187
#define ntohl(value)
Definition: cpu_endian.h:422
@ NO_ERROR
Success.
Definition: error.h:44
Debugging facilities.
error_t nbnsResolve(NetInterface *interface, const char_t *name, IpAddr *ipAddr)
Resolve a host name using NBNS.
Definition: nbns_client.c:53
bool_t nbnsCompareName(const NbnsHeader *message, size_t length, size_t pos, const char_t *name)
Compare NetBIOS names.
Definition: nbns_common.c:288
systime_t osGetSystemTime(void)
Retrieve system time.
#define NBNS_CLIENT_MAX_TIMEOUT
Definition: nbns_client.h:65
Ipv4Addr destIpAddr
Definition: ipcp.h:78