/** * @file * NetBIOS name service sample * *//* * Redistribution and use in source and binary forms, with or without modification,  * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, *    this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, *    this list of conditions and the following disclaimer in the documentation *    and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products *    derived from this software without specific prior written permission.  * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY  * OF SUCH DAMAGE. * * This file is part of the lwIP TCP/IP stack. *  */#include "lwip/opt.h"#include "string.h"#if LWIP_UDP  /* don't build if not configured for use in lwipopts.h */#include "lwip/udp.h"#include "lwip/netif.h"/** This is an example implementation of a NetBIOS name server. * It responds to name queries for a configurable name. * Name resolving is not supported. * * Note that the device doesn't broadcast it's own name so can't * detect duplicate names! *//** NetBIOS name of LWIP device */#ifndef NETBIOS_LWIP_NAME#define NETBIOS_LWIP_NAME "NETBIOSLWIPDEV"#endif/** default port number for "NetBIOS Name service */#define NETBIOS_PORT     137/** size of a NetBIOS name */#define NETBIOS_NAME_LEN 16/** The Time-To-Live for NetBIOS name responds (in seconds) * Default is 300000 seconds (3 days, 11 hours, 20 minutes) */#define NETBIOS_NAME_TTL 300000/** NetBIOS header flags */#define NETB_HFLAG_RESPONSE           0x8000#define NETB_HFLAG_OPCODE             0x7800#define NETB_HFLAG_OPCODE_NAME_QUERY  0x0000#define NETB_HFLAG_AUTHORATIVE        0x0400#define NETB_HFLAG_TRUNCATED          0x0200#define NETB_HFLAG_RECURS_DESIRED     0x0100#define NETB_HFLAG_RECURS_AVAILABLE   0x0080#define NETB_HFLAG_BROADCAST          0x0010#define NETB_HFLAG_REPLYCODE          0x0008#define NETB_HFLAG_REPLYCODE_NOERROR  0x0000/** NetBIOS name flags */#define NETB_NFLAG_UNIQUE             0x8000#define NETB_NFLAG_NODETYPE           0x6000#define NETB_NFLAG_NODETYPE_HNODE     0x6000#define NETB_NFLAG_NODETYPE_MNODE     0x4000#define NETB_NFLAG_NODETYPE_PNODE     0x2000#define NETB_NFLAG_NODETYPE_BNODE     0x0000/** NetBIOS message header */#ifdef PACK_STRUCT_USE_INCLUDES#  include "arch/bpstruct.h"#endifPACK_STRUCT_BEGINstruct netbios_hdr {  PACK_STRUCT_FIELD(u16_t trans_id);  PACK_STRUCT_FIELD(u16_t flags);  PACK_STRUCT_FIELD(u16_t questions);  PACK_STRUCT_FIELD(u16_t answerRRs);  PACK_STRUCT_FIELD(u16_t authorityRRs);  PACK_STRUCT_FIELD(u16_t additionalRRs);} PACK_STRUCT_STRUCT;PACK_STRUCT_END#ifdef PACK_STRUCT_USE_INCLUDES#  include "arch/epstruct.h"#endif/** NetBIOS message name part */#ifdef PACK_STRUCT_USE_INCLUDES#  include "arch/bpstruct.h"#endifPACK_STRUCT_BEGINstruct netbios_name_hdr {  PACK_STRUCT_FIELD(u8_t  nametype);  PACK_STRUCT_FIELD(u8_t  encname[(NETBIOS_NAME_LEN*2)+1]);  PACK_STRUCT_FIELD(u16_t type);  PACK_STRUCT_FIELD(u16_t class);  PACK_STRUCT_FIELD(u32_t ttl);  PACK_STRUCT_FIELD(u16_t datalen);  PACK_STRUCT_FIELD(u16_t flags);  PACK_STRUCT_FIELD(u32_t addr);} PACK_STRUCT_STRUCT;PACK_STRUCT_END#ifdef PACK_STRUCT_USE_INCLUDES#  include "arch/epstruct.h"#endif/** NetBIOS message */#ifdef PACK_STRUCT_USE_INCLUDES#  include "arch/bpstruct.h"#endifPACK_STRUCT_BEGINstruct netbios_resp{  struct netbios_hdr      resp_hdr;  struct netbios_name_hdr resp_name;} PACK_STRUCT_STRUCT;PACK_STRUCT_END#ifdef PACK_STRUCT_USE_INCLUDES#  include "arch/epstruct.h"#endif/** NetBIOS decoding name */static intnetbios_name_decoding( char *name_enc, char *name_dec, int name_dec_len){  char *pname;  char  cname;  char  cnbname;  int   index = 0;  name_dec_len = name_dec_len;//not use  /* Start decoding netbios name. */  pname  = name_enc;  for (;;) {    /* Every two characters of the first level-encoded name     * turn into one character in the decoded name. */    cname = *pname;    if (cname == '\0')      break;    /* no more characters */    if (cname == '.')      break;    /* scope ID follows */    if (cname < 'A' || cname > 'Z') {      /* Not legal. */      return -1;    }    cname -= 'A';    cnbname = cname << 4;    pname++;    cname = *pname;    if (cname == '\0' || cname == '.') {      /* No more characters in the name - but we're in       * the middle of a pair.  Not legal. */      return -1;    }    if (cname < 'A' || cname > 'Z') {      /* Not legal. */      return -1;    }    cname -= 'A';    cnbname |= cname;    pname++;    /* Do we have room to store the character? */    if (index < NETBIOS_NAME_LEN) {      /* Yes - store the character. */      name_dec[index++] = (cnbname!=' '?cnbname:'\0');    }  }  return 0;}/** NetBIOS encoding name */static intnetbios_name_encoding(char *name_enc, char *name_dec, int name_dec_len){  char         *pname;  char          cname;  unsigned char ucname;  int           index = 0;    /* Start encoding netbios name. */  pname = name_enc;  for (;;) {    /* Every two characters of the first level-encoded name     * turn into one character in the decoded name. */    cname = *pname;    if (cname == '\0')      break;    /* no more characters */    if (cname == '.')      break;    /* scope ID follows */    if ((cname < 'A' || cname > 'Z') && (cname < '0' || cname > '9')) {      /* Not legal. */      return -1;    }    /* Do we have room to store the character? */    if (index >= name_dec_len) {      return -1;    }    /* Yes - store the character. */    ucname = cname;    name_dec[index++] = ('A'+((ucname>>4) & 0x0F));    name_dec[index++] = ('A'+( ucname     & 0x0F));    pname++;  }  /* Fill with "space" coding */  for (;index<name_dec_len-1;) {    name_dec[index++] = 'C';    name_dec[index++] = 'A';  }  /* Terminate string */  name_dec[index]='\0';  return 0;}/** NetBIOS Name service recv callback */static voidnetbios_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, struct ip_addr *addr, u16_t port){  arg = arg;//not use;  /* if packet is valid */  if (p != NULL) {    char   netbios_name[NETBIOS_NAME_LEN+1];    struct netbios_hdr*      netbios_hdr      = p->payload;    struct netbios_name_hdr* netbios_name_hdr = (struct netbios_name_hdr*)(netbios_hdr+1);        /* we only answer if we got a default interface */    if (netif_default != NULL) {      /* @todo: do we need to check answerRRs/authorityRRs/additionalRRs? */      /* if the packet is a NetBIOS name query question */      if (((ntohs(netbios_hdr->flags) & NETB_HFLAG_OPCODE) == NETB_HFLAG_OPCODE_NAME_QUERY) &&          ((ntohs(netbios_hdr->flags) & NETB_HFLAG_RESPONSE) == 0) &&           (ntohs(netbios_hdr->questions) == 1)) {        /* decode the NetBIOS name */        netbios_name_decoding( (char*)(netbios_name_hdr->encname), netbios_name, sizeof(netbios_name));        /* if the packet is for us */        if (strcmp( netbios_name, NETBIOS_LWIP_NAME)==0) {          struct pbuf *q;          struct netbios_resp *resp;          q = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct netbios_resp), PBUF_RAM);          if (q != NULL) {            resp = (struct netbios_resp*)q->payload;            /* prepare NetBIOS header response */            resp->resp_hdr.trans_id      = netbios_hdr->trans_id;            resp->resp_hdr.flags         = htons(NETB_HFLAG_RESPONSE |                                                 NETB_HFLAG_OPCODE_NAME_QUERY |                                                 NETB_HFLAG_AUTHORATIVE |                                                 NETB_HFLAG_RECURS_DESIRED);            resp->resp_hdr.questions     = 0;            resp->resp_hdr.answerRRs     = htons(1);            resp->resp_hdr.authorityRRs  = 0;            resp->resp_hdr.additionalRRs = 0;            /* prepare NetBIOS header datas */            memcpy( resp->resp_name.encname, netbios_name_hdr->encname, sizeof(netbios_name_hdr->encname));            resp->resp_name.nametype     = netbios_name_hdr->nametype;            resp->resp_name.type         = netbios_name_hdr->type;            resp->resp_name.class        = netbios_name_hdr->class;            resp->resp_name.ttl          = htonl(NETBIOS_NAME_TTL);            resp->resp_name.datalen      = htons(sizeof(resp->resp_name.flags)+sizeof(resp->resp_name.addr));            resp->resp_name.flags        = htons(NETB_NFLAG_NODETYPE_BNODE);            resp->resp_name.addr         = netif_default->ip_addr.addr;            /* send the NetBIOS response */            udp_sendto(upcb, q, addr, port);                        /* free the "reference" pbuf */            pbuf_free(q);          }        }      }    }    /* free the pbuf */    pbuf_free(p);  }}void netbios_init(void){  struct udp_pcb *pcb;  LWIP_ASSERT("NetBIOS name is too long!", strlen(NETBIOS_LWIP_NAME) < NETBIOS_NAME_LEN);  pcb = udp_new();  if (pcb != NULL) {    udp_bind(pcb, IP_ADDR_ANY, NETBIOS_PORT);    udp_recv(pcb, netbios_recv, pcb);  }}#endif /* LWIP_UDP */