1  /**
2 * @file
3 * NetBIOS name service responder
4 */
5
6/**
7 * @defgroup netbiosns NETBIOS responder
8 * @ingroup apps
9 *
10 * This is an example implementation of a NetBIOS name server.
11 * It responds to name queries for a configurable name.
12 * Name resolving is not supported.
13 *
14 * Note that the device doesn't broadcast it's own name so can't
15 * detect duplicate names!
16 */
17
18/*
19 * Redistribution and use in source and binary forms, with or without modification,
20 * are permitted provided that the following conditions are met:
21 *
22 * 1. Redistributions of source code must retain the above copyright notice,
23 *    this list of conditions and the following disclaimer.
24 * 2. Redistributions in binary form must reproduce the above copyright notice,
25 *    this list of conditions and the following disclaimer in the documentation
26 *    and/or other materials provided with the distribution.
27 * 3. The name of the author may not be used to endorse or promote products
28 *    derived from this software without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
31 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
32 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
33 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
34 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
35 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
38 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
39 * OF SUCH DAMAGE.
40 *
41 * This file is part of the lwIP TCP/IP stack.
42 *
43 * Modifications by Ray Abram to respond to NetBIOS name requests when Incoming name = *
44 * - based on code from "https://github.com/esp8266/Arduino/commit/1f7989b31d26d7df9776a08f36d685eae7ac8f99"
45 * - with permission to relicense to BSD from original author:
46 *   http://www.xpablo.cz/?p=751#more-751
47 */
48
49#include "lwip/apps/netbiosns.h"
50
51#if LWIP_IPV4 && LWIP_UDP  /* don't build if not configured for use in lwipopts.h */
52
53#include "lwip/def.h"
54#include "lwip/udp.h"
55#include "lwip/ip.h"
56#include "lwip/netif.h"
57#include "lwip/prot/iana.h"
58
59#include <string.h>
60
61/** size of a NetBIOS name */
62#define NETBIOS_NAME_LEN 16
63
64/** The Time-To-Live for NetBIOS name responds (in seconds)
65 * Default is 300000 seconds (3 days, 11 hours, 20 minutes) */
66#define NETBIOS_NAME_TTL 300000u
67
68/** NetBIOS header flags */
69#define NETB_HFLAG_RESPONSE           0x8000U
70#define NETB_HFLAG_OPCODE             0x7800U
71#define NETB_HFLAG_OPCODE_NAME_QUERY  0x0000U
72#define NETB_HFLAG_AUTHORATIVE        0x0400U
73#define NETB_HFLAG_TRUNCATED          0x0200U
74#define NETB_HFLAG_RECURS_DESIRED     0x0100U
75#define NETB_HFLAG_RECURS_AVAILABLE   0x0080U
76#define NETB_HFLAG_BROADCAST          0x0010U
77#define NETB_HFLAG_REPLYCODE          0x0008U
78#define NETB_HFLAG_REPLYCODE_NOERROR  0x0000U
79
80/* NetBIOS question types */
81#define NETB_QTYPE_NB                 0x0020U
82#define NETB_QTYPE_NBSTAT             0x0021U
83
84/** NetBIOS name flags */
85#define NETB_NFLAG_UNIQUE             0x8000U
86#define NETB_NFLAG_NODETYPE           0x6000U
87#define NETB_NFLAG_NODETYPE_HNODE     0x6000U
88#define NETB_NFLAG_NODETYPE_MNODE     0x4000U
89#define NETB_NFLAG_NODETYPE_PNODE     0x2000U
90#define NETB_NFLAG_NODETYPE_BNODE     0x0000U
91
92#define NETB_NFLAG_NAME_IN_CONFLICT   0x0800U /* 1=Yes, 0=No */
93#define NETB_NFLAG_NAME_IS_ACTIVE     0x0400U /* 1=Yes, 0=No */
94#define NETB_NFLAG_NAME_IS_PERMANENT  0x0200U /* 1=Yes (Name is Permanent Node Name), 0=No */
95
96/** NetBIOS message header */
97#ifdef PACK_STRUCT_USE_INCLUDES
98#  include "arch/bpstruct.h"
99#endif
100PACK_STRUCT_BEGIN
101struct netbios_hdr {
102  PACK_STRUCT_FIELD(u16_t trans_id);
103  PACK_STRUCT_FIELD(u16_t flags);
104  PACK_STRUCT_FIELD(u16_t questions);
105  PACK_STRUCT_FIELD(u16_t answerRRs);
106  PACK_STRUCT_FIELD(u16_t authorityRRs);
107  PACK_STRUCT_FIELD(u16_t additionalRRs);
108} PACK_STRUCT_STRUCT;
109PACK_STRUCT_END
110#ifdef PACK_STRUCT_USE_INCLUDES
111#  include "arch/epstruct.h"
112#endif
113
114/** NetBIOS message question part */
115#ifdef PACK_STRUCT_USE_INCLUDES
116#  include "arch/bpstruct.h"
117#endif
118PACK_STRUCT_BEGIN
119struct netbios_question_hdr {
120  PACK_STRUCT_FLD_8(u8_t  nametype);
121  PACK_STRUCT_FLD_8(u8_t  encname[(NETBIOS_NAME_LEN * 2) + 1]);
122  PACK_STRUCT_FIELD(u16_t type);
123  PACK_STRUCT_FIELD(u16_t cls);
124} PACK_STRUCT_STRUCT;
125PACK_STRUCT_END
126#ifdef PACK_STRUCT_USE_INCLUDES
127#  include "arch/epstruct.h"
128#endif
129
130/** NetBIOS message name part */
131#ifdef PACK_STRUCT_USE_INCLUDES
132#  include "arch/bpstruct.h"
133#endif
134PACK_STRUCT_BEGIN
135struct netbios_name_hdr {
136  PACK_STRUCT_FLD_8(u8_t  nametype);
137  PACK_STRUCT_FLD_8(u8_t  encname[(NETBIOS_NAME_LEN * 2) + 1]);
138  PACK_STRUCT_FIELD(u16_t type);
139  PACK_STRUCT_FIELD(u16_t cls);
140  PACK_STRUCT_FIELD(u32_t ttl);
141  PACK_STRUCT_FIELD(u16_t datalen);
142  PACK_STRUCT_FIELD(u16_t flags);
143  PACK_STRUCT_FLD_S(ip4_addr_p_t addr);
144} PACK_STRUCT_STRUCT;
145PACK_STRUCT_END
146#ifdef PACK_STRUCT_USE_INCLUDES
147#  include "arch/epstruct.h"
148#endif
149
150/** NetBIOS message */
151#ifdef PACK_STRUCT_USE_INCLUDES
152#  include "arch/bpstruct.h"
153#endif
154PACK_STRUCT_BEGIN
155struct netbios_resp {
156  struct netbios_hdr      resp_hdr;
157  struct netbios_name_hdr resp_name;
158} PACK_STRUCT_STRUCT;
159PACK_STRUCT_END
160#ifdef PACK_STRUCT_USE_INCLUDES
161#  include "arch/epstruct.h"
162#endif
163
164/** The NBNS Structure Responds to a Name Query */
165#ifdef PACK_STRUCT_USE_INCLUDES
166#  include "arch/bpstruct.h"
167#endif
168PACK_STRUCT_BEGIN
169struct netbios_answer {
170  struct netbios_hdr      answer_hdr;
171  /** the length of the next string */
172  PACK_STRUCT_FIELD(u8_t  name_size);
173  /** WARNING!!! this item may be of a different length (we use this struct for transmission) */
174  PACK_STRUCT_FLD_8(u8_t  query_name[(NETBIOS_NAME_LEN * 2) + 1]);
175  PACK_STRUCT_FIELD(u16_t packet_type);
176  PACK_STRUCT_FIELD(u16_t cls);
177  PACK_STRUCT_FIELD(u32_t ttl);
178  PACK_STRUCT_FIELD(u16_t data_length);
179#define OFFSETOF_STRUCT_NETBIOS_ANSWER_NUMBER_OF_NAMES 56
180  /** number of names */
181  PACK_STRUCT_FLD_8(u8_t  number_of_names);
182  /** node name */
183  PACK_STRUCT_FLD_8(u8_t  answer_name[NETBIOS_NAME_LEN]);
184  /** node flags */
185  PACK_STRUCT_FIELD(u16_t answer_name_flags);
186  /** Unit ID */
187  PACK_STRUCT_FLD_8(u8_t  unit_id[6]);
188  /** Jumpers */
189  PACK_STRUCT_FLD_8(u8_t  jumpers);
190  /** Test result */
191  PACK_STRUCT_FLD_8(u8_t  test_result);
192  /** Version number */
193  PACK_STRUCT_FIELD(u16_t version_number);
194  /** Period of statistics */
195  PACK_STRUCT_FIELD(u16_t period_of_statistics);
196  /** Statistics */
197  PACK_STRUCT_FIELD(u16_t number_of_crcs);
198  /** Statistics */
199  PACK_STRUCT_FIELD(u16_t number_of_alignment_errors);
200  /** Statistics */
201  PACK_STRUCT_FIELD(u16_t number_of_collisions);
202  /** Statistics */
203  PACK_STRUCT_FIELD(u16_t number_of_send_aborts);
204  /** Statistics */
205  PACK_STRUCT_FIELD(u32_t number_of_good_sends);
206  /** Statistics */
207  PACK_STRUCT_FIELD(u32_t number_of_good_receives);
208  /** Statistics */
209  PACK_STRUCT_FIELD(u16_t number_of_retransmits);
210  /** Statistics */
211  PACK_STRUCT_FIELD(u16_t number_of_no_resource_condition);
212  /** Statistics */
213  PACK_STRUCT_FIELD(u16_t number_of_free_command_blocks);
214  /** Statistics */
215  PACK_STRUCT_FIELD(u16_t total_number_of_command_blocks);
216  /** Statistics */
217  PACK_STRUCT_FIELD(u16_t max_total_number_of_command_blocks);
218  /** Statistics */
219  PACK_STRUCT_FIELD(u16_t number_of_pending_sessions);
220  /** Statistics */
221  PACK_STRUCT_FIELD(u16_t max_number_of_pending_sessions);
222  /** Statistics */
223  PACK_STRUCT_FIELD(u16_t max_total_sessions_possible);
224  /** Statistics */
225  PACK_STRUCT_FIELD(u16_t session_data_packet_size);
226} PACK_STRUCT_STRUCT;
227PACK_STRUCT_END
228#ifdef PACK_STRUCT_USE_INCLUDES
229#  include "arch/epstruct.h"
230#endif
231
232#ifdef NETBIOS_LWIP_NAME
233#define NETBIOS_LOCAL_NAME NETBIOS_LWIP_NAME
234#else
235static char netbiosns_local_name[NETBIOS_NAME_LEN];
236#define NETBIOS_LOCAL_NAME netbiosns_local_name
237#endif
238
239static struct udp_pcb *netbiosns_pcb;
240
241/** Decode a NetBIOS name (from packet to string) */
242static int
243netbiosns_name_decode(const char *name_enc, char *name_dec, int name_dec_len)
244{
245  const char *pname;
246  char       cname;
247  char       cnbname;
248  int        idx = 0;
249
250  LWIP_UNUSED_ARG(name_dec_len);
251
252  /* Start decoding netbios name. */
253  pname  = name_enc;
254  for (;;) {
255    /* Every two characters of the first level-encoded name
256     * turn into one character in the decoded name. */
257    cname = *pname;
258    if (cname == '\0') {
259      break;  /* no more characters */
260    }
261    if (cname == '.') {
262      break;  /* scope ID follows */
263    }
264    if (!lwip_isupper(cname)) {
265      /* Not legal. */
266      return -1;
267    }
268    cname -= 'A';
269    cnbname = cname << 4;
270    pname++;
271
272    cname = *pname;
273    if (!lwip_isupper(cname)) {
274      /* Not legal. */
275      return -1;
276    }
277    cname -= 'A';
278    cnbname |= cname;
279    pname++;
280
281    /* Do we have room to store the character? */
282    if (idx < NETBIOS_NAME_LEN) {
283      /* Yes - store the character. */
284      name_dec[idx++] = (cnbname != ' ' ? cnbname : '\0');
285    }
286  }
287
288  return 0;
289}
290
291#if 0 /* function currently unused */
292/** Encode a NetBIOS name (from string to packet) - currently unused because
293    we don't ask for names. */
294static int
295netbiosns_name_encode(char *name_enc, char *name_dec, int name_dec_len)
296{
297  char         *pname;
298  char          cname;
299  unsigned char ucname;
300  int           idx = 0;
301
302  /* Start encoding netbios name. */
303  pname = name_enc;
304
305  for (;;) {
306    /* Every two characters of the first level-encoded name
307     * turn into one character in the decoded name. */
308    cname = *pname;
309    if (cname == '\0') {
310      break;  /* no more characters */
311    }
312    if (cname == '.') {
313      break;  /* scope ID follows */
314    }
315    if ((cname < 'A' || cname > 'Z') && (cname < '0' || cname > '9')) {
316      /* Not legal. */
317      return -1;
318    }
319
320    /* Do we have room to store the character? */
321    if (idx >= name_dec_len) {
322      return -1;
323    }
324
325    /* Yes - store the character. */
326    ucname = cname;
327    name_dec[idx++] = ('A' + ((ucname >> 4) & 0x0F));
328    name_dec[idx++] = ('A' + ( ucname     & 0x0F));
329    pname++;
330  }
331
332  /* Fill with "space" coding */
333  for (; idx < name_dec_len - 1;) {
334    name_dec[idx++] = 'C';
335    name_dec[idx++] = 'A';
336  }
337
338  /* Terminate string */
339  name_dec[idx] = '\0';
340
341  return 0;
342}
343#endif /* 0 */
344
345/** NetBIOS Name service recv callback */
346static void
347netbiosns_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
348{
349  LWIP_UNUSED_ARG(arg);
350
351  /* if packet is valid */
352  if (p != NULL) {
353    char   netbios_name[NETBIOS_NAME_LEN + 1];
354    struct netbios_hdr          *netbios_hdr          = (struct netbios_hdr *)p->payload;
355    struct netbios_question_hdr *netbios_question_hdr = (struct netbios_question_hdr *)(netbios_hdr + 1);
356
357    /* is the packet long enough (we need the header in one piece) */
358    if (p->len < (sizeof(struct netbios_hdr) + sizeof(struct netbios_question_hdr))) {
359      /* packet too short */
360      pbuf_free(p);
361      return;
362    }
363    /* we only answer if we got a default interface */
364    if (netif_default != NULL) {
365      /* @todo: do we need to check answerRRs/authorityRRs/additionalRRs? */
366      /* if the packet is a NetBIOS name query question */
367      if (((netbios_hdr->flags & PP_NTOHS(NETB_HFLAG_OPCODE)) == PP_NTOHS(NETB_HFLAG_OPCODE_NAME_QUERY)) &&
368          ((netbios_hdr->flags & PP_NTOHS(NETB_HFLAG_RESPONSE)) == 0) &&
369          (netbios_hdr->questions == PP_NTOHS(1))) {
370        /* decode the NetBIOS name */
371        netbiosns_name_decode((char *)(netbios_question_hdr->encname), netbios_name, sizeof(netbios_name));
372        /* check the request type */
373        if (netbios_question_hdr->type == PP_HTONS(NETB_QTYPE_NB)) {
374          /* if the packet is for us */
375          if (lwip_strnicmp(netbios_name, NETBIOS_LOCAL_NAME, sizeof(NETBIOS_LOCAL_NAME)) == 0) {
376            struct pbuf *q;
377            struct netbios_resp *resp;
378
379            q = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct netbios_resp), PBUF_RAM);
380            if (q != NULL) {
381              resp = (struct netbios_resp *)q->payload;
382
383              /* prepare NetBIOS header response */
384              resp->resp_hdr.trans_id      = netbios_hdr->trans_id;
385              resp->resp_hdr.flags         = PP_HTONS(NETB_HFLAG_RESPONSE |
386                                                      NETB_HFLAG_OPCODE_NAME_QUERY |
387                                                      NETB_HFLAG_AUTHORATIVE |
388                                                      NETB_HFLAG_RECURS_DESIRED);
389              resp->resp_hdr.questions     = 0;
390              resp->resp_hdr.answerRRs     = PP_HTONS(1);
391              resp->resp_hdr.authorityRRs  = 0;
392              resp->resp_hdr.additionalRRs = 0;
393
394              /* prepare NetBIOS header datas */
395              MEMCPY( resp->resp_name.encname, netbios_question_hdr->encname, sizeof(netbios_question_hdr->encname));
396              resp->resp_name.nametype     = netbios_question_hdr->nametype;
397              resp->resp_name.type         = netbios_question_hdr->type;
398              resp->resp_name.cls          = netbios_question_hdr->cls;
399              resp->resp_name.ttl          = PP_HTONL(NETBIOS_NAME_TTL);
400              resp->resp_name.datalen      = PP_HTONS(sizeof(resp->resp_name.flags) + sizeof(resp->resp_name.addr));
401              resp->resp_name.flags        = PP_HTONS(NETB_NFLAG_NODETYPE_BNODE);
402              ip4_addr_copy(resp->resp_name.addr, *netif_ip4_addr(netif_default));
403
404              /* send the NetBIOS response */
405              udp_sendto(upcb, q, addr, port);
406
407              /* free the "reference" pbuf */
408              pbuf_free(q);
409            }
410          }
411#if LWIP_NETBIOS_RESPOND_NAME_QUERY
412        } else if (netbios_question_hdr->type == PP_HTONS(NETB_QTYPE_NBSTAT)) {
413          /* if the packet is for us or general query */
414          if (!lwip_strnicmp(netbios_name, NETBIOS_LOCAL_NAME, sizeof(NETBIOS_LOCAL_NAME)) ||
415              !lwip_strnicmp(netbios_name, "*", sizeof(NETBIOS_LOCAL_NAME))) {
416            /* general query - ask for our IP address */
417            struct pbuf *q;
418            struct netbios_answer *resp;
419
420            q = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct netbios_answer), PBUF_RAM);
421            if (q != NULL) {
422              /* buffer to which a response is compiled */
423              resp = (struct netbios_answer *) q->payload;
424
425              /* Init response to zero, especially the statistics fields */
426              memset(resp, 0, sizeof(*resp));
427
428              /* copy the query to the response ID */
429              resp->answer_hdr.trans_id        = netbios_hdr->trans_id;
430              /* acknowledgment of termination */
431              resp->answer_hdr.flags           = PP_HTONS(NETB_HFLAG_RESPONSE | NETB_HFLAG_OPCODE_NAME_QUERY | NETB_HFLAG_AUTHORATIVE);
432              /* resp->answer_hdr.questions       = PP_HTONS(0); done by memset() */
433              /* serial number of the answer */
434              resp->answer_hdr.answerRRs       = PP_HTONS(1);
435              /* resp->answer_hdr.authorityRRs    = PP_HTONS(0); done by memset() */
436              /* resp->answer_hdr.additionalRRs   = PP_HTONS(0); done by memset() */
437              /* we will copy the length of the station name */
438              resp->name_size                  = netbios_question_hdr->nametype;
439              /* we will copy the queried name */
440              MEMCPY(resp->query_name, netbios_question_hdr->encname, (NETBIOS_NAME_LEN * 2) + 1);
441              /* NBSTAT */
442              resp->packet_type                = PP_HTONS(0x21);
443              /* Internet name */
444              resp->cls                        = PP_HTONS(1);
445              /* resp->ttl                        = PP_HTONL(0); done by memset() */
446              resp->data_length                = PP_HTONS(sizeof(struct netbios_answer) - offsetof(struct netbios_answer, number_of_names));
447              resp->number_of_names            = 1;
448
449              /* make windows see us as workstation, not as a server */
450              memset(resp->answer_name, 0x20, NETBIOS_NAME_LEN - 1);
451              /* strlen is checked to be < NETBIOS_NAME_LEN during initialization */
452              MEMCPY(resp->answer_name, NETBIOS_LOCAL_NAME, strlen(NETBIOS_LOCAL_NAME));
453
454              /* b-node, unique, active */
455              resp->answer_name_flags          = PP_HTONS(NETB_NFLAG_NAME_IS_ACTIVE);
456
457              /* Set responder netif MAC address */
458              SMEMCPY(resp->unit_id, ip_current_input_netif()->hwaddr, sizeof(resp->unit_id));
459
460              udp_sendto(upcb, q, addr, port);
461              pbuf_free(q);
462            }
463          }
464#endif /* LWIP_NETBIOS_RESPOND_NAME_QUERY */
465        }
466      }
467    }
468    /* free the pbuf */
469    pbuf_free(p);
470  }
471}
472
473/**
474 * @ingroup netbiosns
475 * Init netbios responder
476 */
477void
478netbiosns_init(void)
479{
480  /* LWIP_ASSERT_CORE_LOCKED(); is checked by udp_new() */
481#ifdef NETBIOS_LWIP_NAME
482  LWIP_ASSERT("NetBIOS name is too long!", strlen(NETBIOS_LWIP_NAME) < NETBIOS_NAME_LEN);
483#endif
484
485  netbiosns_pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
486  if (netbiosns_pcb != NULL) {
487    /* we have to be allowed to send broadcast packets! */
488    ip_set_option(netbiosns_pcb, SOF_BROADCAST);
489    udp_bind(netbiosns_pcb, IP_ANY_TYPE, LWIP_IANA_PORT_NETBIOS);
490    udp_recv(netbiosns_pcb, netbiosns_recv, netbiosns_pcb);
491  }
492}
493
494#ifndef NETBIOS_LWIP_NAME
495/**
496 * @ingroup netbiosns
497 * Set netbios name. ATTENTION: the hostname must be less than 15 characters!
498 *                              the NetBIOS name spec says the name MUST be upper case, so incoming name is forced into uppercase :-)
499 */
500void
501netbiosns_set_name(const char *hostname)
502{
503  size_t i;
504  size_t copy_len = strlen(hostname);
505  LWIP_ASSERT_CORE_LOCKED();
506  LWIP_ASSERT("NetBIOS name is too long!", copy_len < NETBIOS_NAME_LEN);
507  if (copy_len >= NETBIOS_NAME_LEN) {
508    copy_len = NETBIOS_NAME_LEN - 1;
509  }
510
511  /* make name into upper case */
512  for (i = 0; i < copy_len; i++ ) {
513    netbiosns_local_name[i] = (char)lwip_toupper(hostname[i]);
514  }
515  netbiosns_local_name[copy_len] = '\0';
516}
517#endif /* NETBIOS_LWIP_NAME */
518
519/**
520 * @ingroup netbiosns
521 * Stop netbios responder
522 */
523void
524netbiosns_stop(void)
525{
526  LWIP_ASSERT_CORE_LOCKED();
527  if (netbiosns_pcb != NULL) {
528    udp_remove(netbiosns_pcb);
529    netbiosns_pcb = NULL;
530  }
531}
532
533#endif /* LWIP_IPV4 && LWIP_UDP */
534