source4/libcli/finddcs.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    a composite API for finding a DC and its name
   5
   6    Copyright (C) Volker Lendecke 2005
   7    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2006
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "include/includes.h"
  24 #include "lib/messaging/irpc.h"
  25 #include "librpc/gen_ndr/ndr_irpc.h"
  26 #include "librpc/gen_ndr/samr.h"
  27 #include "libcli/composite/composite.h"
  28 #include "libcli/libcli.h"
  29 #include "libcli/resolve/resolve.h"
  30 #include "libcli/finddcs.h"
  31
  32 struct finddcs_state {
  33         struct composite_context *ctx;
  34         struct messaging_context *msg_ctx;
  35
  36         const char *my_netbios_name;
  37         const char *domain_name;
  38         struct dom_sid *domain_sid;
  39
  40         struct nbtd_getdcname r;
  41         struct nbt_name_status node_status;
  42
  43         int num_dcs;
  44         struct nbt_dc_name *dcs;
  45         uint16_t nbt_port;
  46 };
  47
  48 static void finddcs_name_resolved(struct composite_context *ctx);
  49 static void finddcs_getdc_replied(struct irpc_request *ireq);
  50 static void fallback_node_status(struct finddcs_state *state);
  51 static void fallback_node_status_replied(struct nbt_name_request *name_req);
  52
  53 /*
  54  * Setup and send off the a normal name resolution for the target name.
  55  *
  56  * The domain_sid parameter is optional, and is used in the subsequent getdc request.
  57  *
  58  * This will try a GetDC request, but this may not work.  It will try
  59  * a node status as a fallback, then return no name (but still include
  60  * the IP)
  61  */
  62
  63 struct composite_context *finddcs_send(TALLOC_CTX *mem_ctx,
  64                                        const char *my_netbios_name,
  65                                        uint16_t nbt_port,
  66                                        const char *domain_name,
  67                                        int name_type,
  68                                        struct dom_sid *domain_sid,
  69                                        struct resolve_context *resolve_ctx,
  70                                        struct tevent_context *event_ctx,
  71                                        struct messaging_context *msg_ctx)
  72 {
  73         struct composite_context *c, *creq;
  74         struct finddcs_state *state;
  75         struct nbt_name name;
  76
  77         c = composite_create(mem_ctx, event_ctx);
  78         if (c == NULL) return NULL;
  79
  80         state = talloc(c, struct finddcs_state);
  81         if (composite_nomem(state, c)) return c;
  82         c->private_data = state;
  83
  84         state->ctx = c;
  85
  86         state->nbt_port = nbt_port;
  87         state->my_netbios_name = talloc_strdup(state, my_netbios_name);
  88         state->domain_name = talloc_strdup(state, domain_name);
  89         if (composite_nomem(state->domain_name, c)) return c;
  90
  91         if (domain_sid) {
  92                 state->domain_sid = talloc_reference(state, domain_sid);
  93                 if (composite_nomem(state->domain_sid, c)) return c;
  94         } else {
  95                 state->domain_sid = NULL;
  96         }
  97
  98         state->msg_ctx = msg_ctx;
  99
 100         make_nbt_name(&name, state->domain_name, name_type);
 101         creq = resolve_name_send(resolve_ctx, state, &name, event_ctx);
 102         composite_continue(c, creq, finddcs_name_resolved, state);
 103         return c;
 104 }
 105
 106 /* Having got an name query answer, fire off a GetDC request, so we
 107  * can find the target's all-important name.  (Kerberos and some
 108  * netlogon operations are quite picky about names)
 109  *
 110  * The name is a courtesy, if we don't find it, don't completely fail.
 111  *
 112  * However, if the nbt server is down, fall back to a node status
 113  * request
 114  */
 115 static void finddcs_name_resolved(struct composite_context *ctx)
 116 {
 117         struct finddcs_state *state =
 118                 talloc_get_type(ctx->async.private_data, struct finddcs_state);
 119         struct irpc_request *ireq;
 120         struct server_id *nbt_servers;
 121         const char *address;
 122
 123         state->ctx->status = resolve_name_recv(ctx, state, &address);
 124         if (!composite_is_ok(state->ctx)) return;
 125
 126         /* TODO: This should try and find all the DCs, and give the
 127          * caller them in the order they responded */
 128
 129         state->num_dcs = 1;
 130         state->dcs = talloc_array(state, struct nbt_dc_name, state->num_dcs);
 131         if (composite_nomem(state->dcs, state->ctx)) return;
 132
 133         state->dcs[0].address = talloc_steal(state->dcs, address);
 134
 135         /* Try and find the nbt server.  Fallback to a node status
 136          * request if we can't make this happen The nbt server just
 137          * might not be running, or we may not have a messaging
 138          * context (not root etc) */
 139         if (!state->msg_ctx) {
 140                 fallback_node_status(state);
 141                 return;
 142         }
 143
 144         nbt_servers = irpc_servers_byname(state->msg_ctx, state, "nbt_server");
 145         if ((nbt_servers == NULL) || (nbt_servers[0].id == 0)) {
 146                 fallback_node_status(state);
 147                 return;
 148         }
 149
 150         state->r.in.domainname = state->domain_name;
 151         state->r.in.ip_address = state->dcs[0].address;
 152         state->r.in.my_computername = state->my_netbios_name;
 153         state->r.in.my_accountname = talloc_asprintf(state, "%s$", state->my_netbios_name);
 154         if (composite_nomem(state->r.in.my_accountname, state->ctx)) return;
 155         state->r.in.account_control = ACB_WSTRUST;
 156         state->r.in.domain_sid = state->domain_sid;
 157         if (state->r.in.domain_sid == NULL) {
 158                 state->r.in.domain_sid = talloc_zero(state, struct dom_sid);
 159         }
 160
 161         ireq = irpc_call_send(state->msg_ctx, nbt_servers[0],
 162                               &ndr_table_irpc, NDR_NBTD_GETDCNAME,
 163                               &state->r, state);
 164         if (!ireq) {
 165                 fallback_node_status(state);
 166                 return;
 167         }
 168
 169         composite_continue_irpc(state->ctx, ireq, finddcs_getdc_replied, state);
 170 }
 171
 172 /* Called when the GetDC request returns */
 173 static void finddcs_getdc_replied(struct irpc_request *ireq)
 174 {
 175         struct finddcs_state *state =
 176                 talloc_get_type(ireq->async.private_data, struct finddcs_state);
 177
 178         state->ctx->status = irpc_call_recv(ireq);
 179         if (!composite_is_ok(state->ctx)) return;
 180
 181         state->dcs[0].name = talloc_steal(state->dcs, state->r.out.dcname);
 182         composite_done(state->ctx);
 183 }
 184
 185 /* The GetDC request might not be available (such as occours when the
 186  * NBT server is down).  Fallback to a node status.  It is the best
 187  * hope we have... */
 188 static void fallback_node_status(struct finddcs_state *state)
 189 {
 190         struct nbt_name_socket *nbtsock;
 191         struct nbt_name_request *name_req;
 192
 193         state->node_status.in.name.name = "*";
 194         state->node_status.in.name.type = NBT_NAME_CLIENT;
 195         state->node_status.in.name.scope = NULL;
 196         state->node_status.in.dest_addr = state->dcs[0].address;
 197         state->node_status.in.dest_port = state->nbt_port;
 198         state->node_status.in.timeout = 1;
 199         state->node_status.in.retries = 2;
 200
 201         nbtsock = nbt_name_socket_init(state, state->ctx->event_ctx);
 202         if (composite_nomem(nbtsock, state->ctx)) return;
 203
 204         name_req = nbt_name_status_send(nbtsock, &state->node_status);
 205         if (composite_nomem(name_req, state->ctx)) return;
 206
 207         composite_continue_nbt(state->ctx,
 208                                name_req,
 209                                fallback_node_status_replied,
 210                                state);
 211 }
 212
 213 /* We have a node status reply (or perhaps a timeout) */
 214 static void fallback_node_status_replied(struct nbt_name_request *name_req)
 215 {
 216         int i;
 217         struct finddcs_state *state = talloc_get_type(name_req->async.private_data, struct finddcs_state);
 218         state->ctx->status = nbt_name_status_recv(name_req, state, &state->node_status);
 219         if (!composite_is_ok(state->ctx)) return;
 220
 221         for (i=0; i < state->node_status.out.status.num_names; i++) {
 222                 int j;
 223                 if (state->node_status.out.status.names[i].type == NBT_NAME_SERVER) {
 224                         char *name = talloc_strndup(state->dcs, state->node_status.out.status.names[0].name, 15);
 225                         /* Strip space padding */
 226                         if (name) {
 227                                 j = MIN(strlen(name), 15);
 228                                 for (; j > 0 && name[j - 1] == ' '; j--) {
 229                                         name[j - 1] = '\0';
 230                                 }
 231                         }
 232                         state->dcs[0].name = name;
 233                         composite_done(state->ctx);
 234                         return;
 235                 }
 236         }
 237         composite_error(state->ctx, NT_STATUS_NO_LOGON_SERVERS);
 238 }
 239
 240 NTSTATUS finddcs_recv(struct composite_context *c, TALLOC_CTX *mem_ctx,
 241                       int *num_dcs, struct nbt_dc_name **dcs)
 242 {
 243         NTSTATUS status = composite_wait(c);
 244         if (NT_STATUS_IS_OK(status)) {
 245                 struct finddcs_state *state =
 246                         talloc_get_type(c->private_data, struct finddcs_state);
 247                 *num_dcs = state->num_dcs;
 248                 *dcs = talloc_steal(mem_ctx, state->dcs);
 249         }
 250         talloc_free(c);
 251         return status;
 252 }
 253
 254 NTSTATUS finddcs(TALLOC_CTX *mem_ctx,
 255                  const char *my_netbios_name,
 256                  uint16_t nbt_port,
 257                  const char *domain_name, int name_type,
 258                  struct dom_sid *domain_sid,
 259                  struct resolve_context *resolve_ctx,
 260                  struct tevent_context *event_ctx,
 261                  struct messaging_context *msg_ctx,
 262                  int *num_dcs, struct nbt_dc_name **dcs)
 263 {
 264         struct composite_context *c = finddcs_send(mem_ctx,
 265                                                    my_netbios_name,
 266                                                    nbt_port,
 267                                                    domain_name, name_type,
 268                                                    domain_sid,
 269                                                    resolve_ctx,
 270                                                    event_ctx, msg_ctx);
 271         return finddcs_recv(c, mem_ctx, num_dcs, dcs);
 272 }