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 2 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, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "include/includes.h"
  25 #include "lib/messaging/irpc.h"
  26 #include "librpc/gen_ndr/ndr_irpc.h"
  27 #include "librpc/gen_ndr/samr.h"
  28 #include "libcli/composite/composite.h"
  29 #include "libcli/libcli.h"
  30 #include "libcli/resolve/resolve.h"
  31
  32 struct finddcs_state {
  33         struct composite_context *ctx;
  34         struct messaging_context *msg_ctx;
  35
  36         const char *domain_name;
  37         struct dom_sid *domain_sid;
  38
  39         struct nbtd_getdcname r;
  40         struct nbt_name_status node_status;
  41
  42         int num_dcs;
  43         struct nbt_dc_name *dcs;
  44 };
  45
  46 static void finddcs_name_resolved(struct composite_context *ctx);
  47 static void finddcs_getdc_replied(struct irpc_request *ireq);
  48 static void fallback_node_status(struct finddcs_state *state);
  49 static void fallback_node_status_replied(struct nbt_name_request *name_req);
  50
  51 /*
  52  * Setup and send off the a normal name resolution for the target name.
  53  *
  54  * The domain_sid parameter is optional, and is used in the subsequent getdc request.
  55  *
  56  * This will try a GetDC request, but this may not work.  It will try
  57  * a node status as a fallback, then return no name (but still include
  58  * the IP)
  59  */
  60
  61 struct composite_context *finddcs_send(TALLOC_CTX *mem_ctx,
  62                                        const char *domain_name,
  63                                        int name_type,
  64                                        struct dom_sid *domain_sid,
  65                                        const char **methods,
  66                                        struct event_context *event_ctx,
  67                                        struct messaging_context *msg_ctx)
  68 {
  69         struct composite_context *c, *creq;
  70         struct finddcs_state *state;
  71         struct nbt_name name;
  72
  73         c = composite_create(mem_ctx, event_ctx);
  74         if (c == NULL) return NULL;
  75
  76         state = talloc(c, struct finddcs_state);
  77         if (composite_nomem(state, c)) return c;
  78         c->private_data = state;
  79
  80         state->ctx = c;
  81
  82         state->domain_name = talloc_strdup(state, domain_name);
  83         if (composite_nomem(state->domain_name, c)) return c;
  84
  85         if (domain_sid) {
  86                 state->domain_sid = talloc_reference(state, domain_sid);
  87                 if (composite_nomem(state->domain_sid, c)) return c;
  88         } else {
  89                 state->domain_sid = NULL;
  90         }
  91
  92         state->msg_ctx = msg_ctx;
  93
  94         make_nbt_name(&name, state->domain_name, name_type);
  95         creq = resolve_name_send(&name, event_ctx,
  96                                  methods);
  97         composite_continue(c, creq, finddcs_name_resolved, state);
  98         return c;
  99 }
 100
 101 /* Having got an name query answer, fire off a GetDC request, so we
 102  * can find the target's all-important name.  (Kerberos and some
 103  * netlogon operations are quite picky about names)
 104  *
 105  * The name is a courtesy, if we don't find it, don't completely fail.
 106  *
 107  * However, if the nbt server is down, fall back to a node status
 108  * request
 109  */
 110 static void finddcs_name_resolved(struct composite_context *ctx)
 111 {
 112         struct finddcs_state *state =
 113                 talloc_get_type(ctx->async.private_data, struct finddcs_state);
 114         struct irpc_request *ireq;
 115         struct server_id *nbt_servers;
 116         const char *address;
 117
 118         state->ctx->status = resolve_name_recv(ctx, state, &address);
 119         if (!composite_is_ok(state->ctx)) return;
 120
 121         state->num_dcs = 1;
 122         state->dcs = talloc_array(state, struct nbt_dc_name, state->num_dcs);
 123         if (composite_nomem(state->dcs, state->ctx)) return;
 124
 125         state->dcs[0].address = talloc_steal(state->dcs, address);
 126
 127         /* Try and find the nbt server.  Fallback to a node status
 128          * request if we can't make this happen The nbt server just
 129          * might not be running, or we may not have a messaging
 130          * context (not root etc) */
 131         if (!state->msg_ctx) {
 132                 fallback_node_status(state);
 133                 return;
 134         }
 135
 136         nbt_servers = irpc_servers_byname(state->msg_ctx, "nbt_server");
 137         if ((nbt_servers == NULL) || (nbt_servers[0].id == 0)) {
 138                 fallback_node_status(state);
 139                 return;
 140         }
 141
 142         state->r.in.domainname = state->domain_name;
 143         state->r.in.ip_address = state->dcs[0].address;
 144         state->r.in.my_computername = lp_netbios_name();
 145         state->r.in.my_accountname = talloc_asprintf(state, "%s$",
 146                                                      lp_netbios_name());
 147         if (composite_nomem(state->r.in.my_accountname, state->ctx)) return;
 148         state->r.in.account_control = ACB_WSTRUST;
 149         state->r.in.domain_sid = state->domain_sid;
 150
 151         ireq = irpc_call_send(state->msg_ctx, nbt_servers[0],
 152                               &dcerpc_table_irpc, DCERPC_NBTD_GETDCNAME,
 153                               &state->r, state);
 154         if (!ireq) {
 155                 fallback_node_status(state);
 156                 return;
 157         }
 158
 159         composite_continue_irpc(state->ctx, ireq, finddcs_getdc_replied, state);
 160 }
 161
 162 /* Called when the GetDC request returns */
 163 static void finddcs_getdc_replied(struct irpc_request *ireq)
 164 {
 165         struct finddcs_state *state =
 166                 talloc_get_type(ireq->async.private, struct finddcs_state);
 167
 168         state->ctx->status = irpc_call_recv(ireq);
 169         if (!composite_is_ok(state->ctx)) return;
 170
 171         state->dcs[0].name = talloc_steal(state->dcs, state->r.out.dcname);
 172         composite_done(state->ctx);
 173 }
 174
 175 /* The GetDC request might not be availible (such as occours when the
 176  * NBT server is down).  Fallback to a node status.  It is the best
 177  * hope we have... */
 178 static void fallback_node_status(struct finddcs_state *state)
 179 {
 180         struct nbt_name_socket *nbtsock;
 181         struct nbt_name_request *name_req;
 182
 183         state->node_status.in.name.name = "*";
 184         state->node_status.in.name.type = NBT_NAME_CLIENT;
 185         state->node_status.in.name.scope = NULL;
 186         state->node_status.in.dest_addr = state->dcs[0].address;
 187         state->node_status.in.timeout = 1;
 188         state->node_status.in.retries = 2;
 189
 190         nbtsock = nbt_name_socket_init(state, state->ctx->event_ctx);
 191         if (composite_nomem(nbtsock, state->ctx)) return;
 192
 193         name_req = nbt_name_status_send(nbtsock, &state->node_status);
 194         if (composite_nomem(name_req, state->ctx)) return;
 195
 196         composite_continue_nbt(state->ctx,
 197                                name_req,
 198                                fallback_node_status_replied,
 199                                state);
 200 }
 201
 202 /* We have a node status reply (or perhaps a timeout) */
 203 static void fallback_node_status_replied(struct nbt_name_request *name_req)
 204 {
 205         int i;
 206         struct finddcs_state *state = talloc_get_type(name_req->async.private, struct finddcs_state);
 207         state->ctx->status = nbt_name_status_recv(name_req, state, &state->node_status);
 208         if (!composite_is_ok(state->ctx)) return;
 209
 210         for (i=0; i < state->node_status.out.status.num_names; i++) {
 211                 int j;
 212                 if (state->node_status.out.status.names[i].type == NBT_NAME_SERVER) {
 213                         char *name = talloc_strndup(state->dcs, state->node_status.out.status.names[0].name, 15);
 214                         /* Strip space padding */
 215                         if (name) {
 216                                 j = MIN(strlen(name), 15);
 217                                 for (; j > 0 && name[j - 1] == ' '; j--) {
 218                                         name[j - 1] = '\0';
 219                                 }
 220                         }
 221                         state->dcs[0].name = name;
 222                         composite_done(state->ctx);
 223                         return;
 224                 }
 225         }
 226         composite_error(state->ctx, NT_STATUS_NO_LOGON_SERVERS);
 227 }
 228
 229 NTSTATUS finddcs_recv(struct composite_context *c, TALLOC_CTX *mem_ctx,
 230                       int *num_dcs, struct nbt_dc_name **dcs)
 231 {
 232         NTSTATUS status = composite_wait(c);
 233         if (NT_STATUS_IS_OK(status)) {
 234                 struct finddcs_state *state =
 235                         talloc_get_type(c->private_data, struct finddcs_state);
 236                 *num_dcs = state->num_dcs;
 237                 *dcs = talloc_steal(mem_ctx, state->dcs);
 238         }
 239         talloc_free(c);
 240         return status;
 241 }
 242
 243 NTSTATUS finddcs(TALLOC_CTX *mem_ctx,
 244                  const char *domain_name, int name_type,
 245                  struct dom_sid *domain_sid,
 246                  const char **methods,
 247                  struct event_context *event_ctx,
 248                  struct messaging_context *msg_ctx,
 249                  int *num_dcs, struct nbt_dc_name **dcs)
 250 {
 251         struct composite_context *c = finddcs_send(mem_ctx,
 252                                                    domain_name, name_type,
 253                                                    domain_sid, methods,
 254                                                    event_ctx, msg_ctx);
 255         return finddcs_recv(c, mem_ctx, num_dcs, dcs);
 256 }