source3/client/dnsbrowse.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    DNS-SD browse client
   4    Copyright (C) Rishi Srivatsavai 2007
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "client/client_proto.h"
  22
  23 #ifdef WITH_DNSSD_SUPPORT
  24
  25 #include <dns_sd.h>
  26 #include "system/select.h"
  27
  28 /* Holds service instances found during DNS browse */
  29 struct mdns_smbsrv_result
  30 {
  31         char *serviceName;
  32         char *regType;
  33         char *domain;
  34         uint32_t ifIndex;
  35         struct mdns_smbsrv_result *nextResult;
  36 };
  37
  38 /* Maintains state during DNS browse */
  39 struct mdns_browse_state
  40 {
  41         struct mdns_smbsrv_result *listhead; /* Browse result list head */
  42         int browseDone;
  43
  44 };
  45
  46
  47 static void
  48 do_smb_resolve_reply (DNSServiceRef sdRef, DNSServiceFlags flags,
  49                 uint32_t interfaceIndex, DNSServiceErrorType errorCode,
  50                 const char *fullname, const char *hosttarget, uint16_t port,
  51                 uint16_t txtLen, const unsigned char *txtRecord, void *context)
  52 {
  53         printf("SMB service available on %s port %u\n",
  54                 hosttarget, ntohs(port));
  55 }
  56
  57
  58 static void do_smb_resolve(struct mdns_smbsrv_result *browsesrv)
  59 {
  60         DNSServiceRef mdns_conn_sdref = NULL;
  61         int mdnsfd;
  62         int fdsetsz;
  63         int ret;
  64         struct timeval tv;
  65         DNSServiceErrorType err;
  66
  67         TALLOC_CTX * ctx = talloc_tos();
  68
  69         err = DNSServiceResolve(&mdns_conn_sdref, 0 /* flags */,
  70                 browsesrv->ifIndex,
  71                 browsesrv->serviceName, browsesrv->regType, browsesrv->domain,
  72                 do_smb_resolve_reply, NULL);
  73
  74         if (err != kDNSServiceErr_NoError) {
  75                 return;
  76         }
  77
  78         mdnsfd = DNSServiceRefSockFD(mdns_conn_sdref);
  79         for (;;)  {
  80                 int revents;
  81
  82                 ret = poll_one_fd(mdnsfd, POLLIN|POLLHUP, 1000, &revents);
  83                 if (ret <= 0 && errno != EINTR) {
  84                         break;
  85                 }
  86
  87                 if (revents & (POLLIN|POLLHUP|POLLERR)) {
  88                         /* Invoke callback function */
  89                         DNSServiceProcessResult(mdns_conn_sdref);
  90                         break;
  91                 }
  92         }
  93
  94         TALLOC_FREE(fdset);
  95         DNSServiceRefDeallocate(mdns_conn_sdref);
  96 }
  97
  98
  99 static void
 100 do_smb_browse_reply(DNSServiceRef sdRef, DNSServiceFlags flags,
 101         uint32_t interfaceIndex, DNSServiceErrorType errorCode,
 102         const char  *serviceName, const char *regtype,
 103         const char  *replyDomain, void  *context)
 104 {
 105         struct mdns_browse_state *bstatep = (struct mdns_browse_state *)context;
 106         struct mdns_smbsrv_result *bresult;
 107
 108         if (bstatep == NULL) {
 109                 return;
 110         }
 111
 112         if (errorCode != kDNSServiceErr_NoError) {
 113                 bstatep->browseDone = 1;
 114                 return;
 115         }
 116
 117         if (flags & kDNSServiceFlagsMoreComing) {
 118                 bstatep->browseDone = 0;
 119         } else {
 120                 bstatep->browseDone = 1;
 121         }
 122
 123         if (!(flags & kDNSServiceFlagsAdd)) {
 124                 return;
 125         }
 126
 127         bresult = talloc_array(talloc_tos(), struct mdns_smbsrv_result, 1);
 128         if (bresult == NULL) {
 129                 return;
 130         }
 131
 132         if (bstatep->listhead != NULL) {
 133                 bresult->nextResult = bstatep->listhead;
 134         }
 135
 136         bresult->serviceName = talloc_strdup(talloc_tos(), serviceName);
 137         bresult->regType = talloc_strdup(talloc_tos(), regtype);
 138         bresult->domain = talloc_strdup(talloc_tos(), replyDomain);
 139         bresult->ifIndex = interfaceIndex;
 140         bstatep->listhead = bresult;
 141 }
 142
 143 int do_smb_browse(void)
 144 {
 145         int mdnsfd;
 146         int fdsetsz;
 147         int ret;
 148         struct mdns_browse_state bstate;
 149         struct mdns_smbsrv_result *resptr;
 150         struct timeval tv;
 151         DNSServiceRef mdns_conn_sdref = NULL;
 152         DNSServiceErrorType err;
 153
 154         TALLOC_CTX * ctx = talloc_stackframe();
 155
 156         ZERO_STRUCT(bstate);
 157
 158         err = DNSServiceBrowse(&mdns_conn_sdref, 0, 0, "_smb._tcp", "",
 159                         do_smb_browse_reply, &bstate);
 160
 161         if (err != kDNSServiceErr_NoError) {
 162                 d_printf("Error connecting to the Multicast DNS daemon\n");
 163                 TALLOC_FREE(ctx);
 164                 return 1;
 165         }
 166
 167         mdnsfd = DNSServiceRefSockFD(mdns_conn_sdref);
 168         for (;;)  {
 169                 int revents;
 170
 171                 ret = poll_one_fd(mdnsfd, POLLIN|POLLHUP, 1000, &revents);
 172                 if (ret <= 0 && errno != EINTR) {
 173                         break;
 174                 }
 175
 176                 if (revents & (POLLIN|POLLHUP|POLLERR)) {
 177                         /* Invoke callback function */
 178                         if (DNSServiceProcessResult(mdns_conn_sdref)) {
 179                                 break;
 180                         }
 181                         if (bstate.browseDone) {
 182                                 break;
 183                         }
 184                 }
 185         }
 186
 187         DNSServiceRefDeallocate(mdns_conn_sdref);
 188
 189         if (bstate.listhead != NULL) {
 190                 resptr = bstate.listhead;
 191                 while (resptr != NULL) {
 192                         struct mdns_smbsrv_result *oldresptr;
 193                         oldresptr = resptr;
 194
 195                         /* Resolve smb service instance */
 196                         do_smb_resolve(resptr);
 197
 198                         resptr = resptr->nextResult;
 199                 }
 200         }
 201
 202         TALLOC_FREE(ctx);
 203         return 0;
 204 }
 205
 206 #else /* WITH_DNSSD_SUPPORT */
 207
 208 int do_smb_browse(void)
 209 {
 210     d_printf("DNS-SD browsing is not supported on this platform\n");
 211     return 1;
 212 }
 213
 214 #endif /* WITH_DNSSD_SUPPORT */
 215
 216