source/libcli/nbt/nbtsocket.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    low level socket handling for nbt requests
   5
   6    Copyright (C) Andrew Tridgell 2005
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24 #include "events.h"
  25 #include "dlinklist.h"
  26 #include "libcli/nbt/libnbt.h"
  27
  28 #define NBT_MAX_PACKET_SIZE 2048
  29 #define NBT_MAX_REPLIES 1000
  30
  31 /*
  32   destroy a pending request
  33 */
  34 static int nbt_name_request_destructor(void *ptr)
  35 {
  36         struct nbt_name_request *req = talloc_get_type(ptr, struct nbt_name_request);
  37
  38         if (req->state == NBT_REQUEST_SEND) {
  39                 DLIST_REMOVE(req->nbtsock->send_queue, req);
  40         }
  41         if (req->state == NBT_REQUEST_WAIT) {
  42                 req->nbtsock->num_pending--;
  43         }
  44         if (req->request->name_trn_id != 0) {
  45                 idr_remove(req->nbtsock->idr, req->request->name_trn_id);
  46                 req->request->name_trn_id = 0;
  47         }
  48         if (req->te) {
  49                 event_remove_timed(req->nbtsock->event_ctx, req->te);
  50                 req->te = NULL;
  51         }
  52         if (req->nbtsock->send_queue == NULL) {
  53                 req->nbtsock->fde->flags &= ~EVENT_FD_WRITE;
  54         }
  55         if (req->nbtsock->num_pending == 0) {
  56                 req->nbtsock->fde->flags &= ~EVENT_FD_READ;
  57         }
  58         return 0;
  59 }
  60
  61
  62 /*
  63   handle send events on a nbt name socket
  64 */
  65 static void nbt_name_socket_send(struct nbt_name_socket *nbtsock)
  66 {
  67         struct nbt_name_request *req = nbtsock->send_queue;
  68         TALLOC_CTX *tmp_ctx = talloc_new(req);
  69         NTSTATUS status;
  70
  71         while ((req = nbtsock->send_queue)) {
  72                 DATA_BLOB blob;
  73                 size_t len;
  74
  75                 if (DEBUGLVL(10)) {
  76                         DEBUG(10,("Sending nbt packet:\n"));
  77                         NDR_PRINT_DEBUG(nbt_name_packet, req->request);
  78                 }
  79
  80                 status = ndr_push_struct_blob(&blob, tmp_ctx, req->request,
  81                                               (ndr_push_flags_fn_t)
  82                                               ndr_push_nbt_name_packet);
  83                 if (!NT_STATUS_IS_OK(status)) goto failed;
  84
  85                 if (req->request->operation & NBT_FLAG_BROADCAST) {
  86                         socket_set_option(nbtsock->sock, "SO_BROADCAST", "1");
  87                 }
  88
  89                 len = blob.length;
  90                 status = socket_sendto(nbtsock->sock, &blob, &len, 0,
  91                                        req->dest_addr, req->dest_port);
  92                 if (NT_STATUS_IS_ERR(status)) goto failed;
  93
  94                 if (!NT_STATUS_IS_OK(status)) {
  95                         talloc_free(tmp_ctx);
  96                         return;
  97                 }
  98
  99                 DLIST_REMOVE(nbtsock->send_queue, req);
 100                 req->state = NBT_REQUEST_WAIT;
 101                 nbtsock->fde->flags |= EVENT_FD_READ;
 102                 nbtsock->num_pending++;
 103         }
 104
 105         nbtsock->fde->flags &= ~EVENT_FD_WRITE;
 106         talloc_free(tmp_ctx);
 107         return;
 108
 109 failed:
 110         DLIST_REMOVE(nbtsock->send_queue, req);
 111         nbt_name_request_destructor(req);
 112         req->status = status;
 113         req->state = NBT_REQUEST_ERROR;
 114         talloc_free(tmp_ctx);
 115         return;
 116 }
 117
 118
 119 /*
 120   handle recv events on a nbt name socket
 121 */
 122 static void nbt_name_socket_recv(struct nbt_name_socket *nbtsock)
 123 {
 124         TALLOC_CTX *tmp_ctx = talloc_new(nbtsock);
 125         NTSTATUS status;
 126         const char *src_addr;
 127         int src_port;
 128         DATA_BLOB blob;
 129         size_t nread;
 130         struct nbt_name_packet *packet;
 131         struct nbt_name_request *req;
 132
 133         blob = data_blob_talloc(tmp_ctx, NULL, NBT_MAX_PACKET_SIZE);
 134         if (blob.data == NULL) {
 135                 talloc_free(tmp_ctx);
 136                 return;
 137         }
 138
 139         status = socket_recvfrom(nbtsock->sock, blob.data, blob.length, &nread, 0,
 140                                  &src_addr, &src_port);
 141         if (!NT_STATUS_IS_OK(status)) {
 142                 talloc_free(tmp_ctx);
 143                 return;
 144         }
 145         talloc_steal(tmp_ctx, src_addr);
 146
 147         packet = talloc(tmp_ctx, struct nbt_name_packet);
 148         if (packet == NULL) {
 149                 talloc_free(tmp_ctx);
 150                 return;
 151         }
 152
 153         status = ndr_pull_struct_blob(&blob, packet, packet,
 154                                       (ndr_pull_flags_fn_t)ndr_pull_nbt_name_packet);
 155         if (!NT_STATUS_IS_OK(status)) {
 156                 DEBUG(2,("Failed to parse incoming NBT name packet - %s\n",
 157                          nt_errstr(status)));
 158                 talloc_free(tmp_ctx);
 159                 return;
 160         }
 161
 162         if (DEBUGLVL(10)) {
 163                 DEBUG(10,("Received nbt packet:\n"));
 164                 NDR_PRINT_DEBUG(nbt_name_packet, packet);
 165         }
 166
 167         if (!(packet->operation & NBT_FLAG_REPLY)) {
 168                 talloc_free(tmp_ctx);
 169                 return;
 170         }
 171
 172         /* find the matching request */
 173         req = idr_find(nbtsock->idr, packet->name_trn_id);
 174         if (req == NULL) {
 175                 DEBUG(2,("Failed to match request for incoming name packet id 0x%04x\n",
 176                          packet->name_trn_id));
 177                 talloc_free(tmp_ctx);
 178                 return;
 179         }
 180
 181         req->replies = talloc_realloc(req, req->replies, struct nbt_name_reply, req->num_replies+1);
 182         if (req->replies == NULL) {
 183                 nbt_name_request_destructor(req);
 184                 req->state = NBT_REQUEST_DONE;
 185                 req->status = NT_STATUS_NO_MEMORY;
 186                 talloc_free(tmp_ctx);
 187                 return;
 188         }
 189
 190         req->replies[req->num_replies].reply_addr = talloc_steal(req, src_addr);
 191         req->replies[req->num_replies].reply_port = src_port;
 192         req->replies[req->num_replies].packet = talloc_steal(req, packet);
 193         req->num_replies++;
 194
 195         /* if we don't want multiple replies then we are done */
 196         if (!req->allow_multiple_replies ||
 197             req->num_replies == NBT_MAX_REPLIES) {
 198                 nbt_name_request_destructor(req);
 199                 req->state = NBT_REQUEST_DONE;
 200                 req->status = NT_STATUS_OK;
 201         }
 202
 203         talloc_free(tmp_ctx);
 204 }
 205
 206 /*
 207   handle fd events on a nbt_name_socket
 208 */
 209 static void nbt_name_socket_handler(struct event_context *ev, struct fd_event *fde,
 210                                     struct timeval t, uint16_t flags)
 211 {
 212         struct nbt_name_socket *nbtsock = talloc_get_type(fde->private,
 213                                                           struct nbt_name_socket);
 214         if (flags & EVENT_FD_WRITE) {
 215                 nbt_name_socket_send(nbtsock);
 216         } else if (flags & EVENT_FD_READ) {
 217                 nbt_name_socket_recv(nbtsock);
 218         }
 219 }
 220
 221
 222 /*
 223   initialise a nbt_name_socket. The event_ctx is optional, if provided
 224   then operations will use that event context
 225 */
 226 struct nbt_name_socket *nbt_name_socket_init(TALLOC_CTX *mem_ctx,
 227                                              struct event_context *event_ctx)
 228 {
 229         struct nbt_name_socket *nbtsock;
 230         NTSTATUS status;
 231         struct fd_event fde;
 232
 233         nbtsock = talloc(mem_ctx, struct nbt_name_socket);
 234         if (nbtsock == NULL) goto failed;
 235
 236         if (event_ctx == NULL) {
 237                 nbtsock->event_ctx = event_context_init(nbtsock);
 238         } else {
 239                 nbtsock->event_ctx = talloc_reference(nbtsock, event_ctx);
 240         }
 241         if (nbtsock->event_ctx == NULL) goto failed;
 242
 243         status = socket_create("ip", SOCKET_TYPE_DGRAM, &nbtsock->sock, 0);
 244         if (!NT_STATUS_IS_OK(status)) goto failed;
 245
 246         talloc_steal(nbtsock, nbtsock->sock);
 247
 248         nbtsock->idr = idr_init(nbtsock);
 249         if (nbtsock->idr == NULL) goto failed;
 250
 251         nbtsock->send_queue = NULL;
 252         nbtsock->num_pending = 0;
 253
 254         fde.fd = socket_get_fd(nbtsock->sock);
 255         fde.flags = 0;
 256         fde.handler = nbt_name_socket_handler;
 257         fde.private = nbtsock;
 258         nbtsock->fde = event_add_fd(nbtsock->event_ctx, &fde);
 259
 260         return nbtsock;
 261
 262 failed:
 263         talloc_free(nbtsock);
 264         return NULL;
 265 }
 266
 267 /*
 268   handle a request timeout
 269 */
 270 static void nbt_name_socket_timeout(struct event_context *ev, struct timed_event *te,
 271                                     struct timeval t)
 272 {
 273         struct nbt_name_request *req = talloc_get_type(te->private,
 274                                                        struct nbt_name_request);
 275         nbt_name_request_destructor(req);
 276         req->state = NBT_REQUEST_TIMEOUT;
 277         req->status = NT_STATUS_IO_TIMEOUT;
 278 }
 279
 280 /*
 281   send off a nbt name request
 282 */
 283 struct nbt_name_request *nbt_name_request_send(struct nbt_name_socket *nbtsock,
 284                                                const char *dest_addr, int dest_port,
 285                                                struct nbt_name_packet *request,
 286                                                struct timeval timeout,
 287                                                BOOL allow_multiple_replies)
 288 {
 289         struct nbt_name_request *req;
 290         struct timed_event te;
 291         int id;
 292
 293         req = talloc_zero(nbtsock, struct nbt_name_request);
 294         if (req == NULL) goto failed;
 295
 296         req->nbtsock = nbtsock;
 297         req->dest_addr = dest_addr;
 298         req->dest_port = dest_port;
 299         req->request = talloc_reference(req, request);
 300         req->allow_multiple_replies = allow_multiple_replies;
 301         req->state = NBT_REQUEST_SEND;
 302
 303         if (req->request->name_trn_id == 0) {
 304                 req->request->name_trn_id = random() % UINT16_MAX;
 305         }
 306
 307         id = idr_get_new_above(req->nbtsock->idr, req,
 308                                req->request->name_trn_id, UINT16_MAX);
 309         if (id == -1) {
 310                 id = idr_get_new_above(req->nbtsock->idr, req, 1+(random()%10000),
 311                                        UINT16_MAX);
 312         }
 313         if (id == -1) goto failed;
 314
 315         te.next_event = timeout;
 316         te.handler = nbt_name_socket_timeout;
 317         te.private = req;
 318         req->te = event_add_timed(nbtsock->event_ctx, &te);
 319
 320         talloc_set_destructor(req, nbt_name_request_destructor);
 321
 322         DLIST_ADD_END(nbtsock->send_queue, req, struct nbt_name_request *);
 323
 324         nbtsock->fde->flags |= EVENT_FD_WRITE;
 325
 326         return req;
 327
 328 failed:
 329         talloc_free(req);
 330         return NULL;
 331 }
 332
 333 /*
 334   wait for a nbt request to complete
 335 */
 336 NTSTATUS nbt_name_request_recv(struct nbt_name_request *req)
 337 {
 338         if (!req) return NT_STATUS_NO_MEMORY;
 339
 340         while (req->state < NBT_REQUEST_DONE) {
 341                 if (event_loop_once(req->nbtsock->event_ctx) != 0) {
 342                         req->state = NBT_REQUEST_ERROR;
 343                         req->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 344                 }
 345         }
 346         return req->status;
 347 }