source/libcli/resolve/resolve.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    general name resolution interface
   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 "lib/events/events.h"
  25 #include "libcli/raw/libcliraw.h"
  26 #include "libcli/composite/composite.h"
  27
  28 struct resolve_state {
  29         struct nbt_name name;
  30         const char **methods;
  31         struct composite_context *req;
  32         const char *reply_addr;
  33 };
  34
  35 static struct composite_context *setup_next_method(struct composite_context *c);
  36
  37 /* pointers to the resolver backends */
  38 static const struct resolve_method {
  39         const char *name;
  40         struct composite_context *(*send_fn)(struct nbt_name *, struct event_context *);
  41         NTSTATUS (*recv_fn)(struct composite_context *, TALLOC_CTX *, const char **);
  42 } methods[] = {
  43         { "bcast", resolve_name_bcast_send, resolve_name_bcast_recv },
  44         { "wins",  resolve_name_wins_send, resolve_name_wins_recv },
  45         { "host",  resolve_name_host_send, resolve_name_host_recv }
  46 };
  47
  48
  49 /*
  50    find a matching backend
  51 */
  52 static const struct resolve_method *find_method(const char *name)
  53 {
  54         int i;
  55         if (name == NULL) return NULL;
  56         for (i=0;i<ARRAY_SIZE(methods);i++) {
  57                 if (strcasecmp(name, methods[i].name) == 0) {
  58                         return &methods[i];
  59                 }
  60         }
  61         return NULL;
  62 }
  63
  64 /*
  65   handle completion of one name resolve method
  66 */
  67 static void resolve_handler(struct composite_context *req)
  68 {
  69         struct composite_context *c = req->async.private;
  70         struct resolve_state *state = talloc_get_type(c->private, struct resolve_state);
  71         const struct resolve_method *method = find_method(state->methods[0]);
  72
  73         c->status = method->recv_fn(req, state, &state->reply_addr);
  74
  75         if (!NT_STATUS_IS_OK(c->status)) {
  76                 state->methods++;
  77                 state->req = setup_next_method(c);
  78                 if (state->req != NULL) {
  79                         return;
  80                 }
  81         }
  82
  83         if (!NT_STATUS_IS_OK(c->status)) {
  84                 c->state = SMBCLI_REQUEST_ERROR;
  85         } else {
  86                 c->state = SMBCLI_REQUEST_DONE;
  87         }
  88         if (c->async.fn) {
  89                 c->async.fn(c);
  90         }
  91 }
  92
  93
  94 static struct composite_context *setup_next_method(struct composite_context *c)
  95 {
  96         struct resolve_state *state = talloc_get_type(c->private, struct resolve_state);
  97         struct composite_context *req = NULL;
  98
  99         do {
 100                 const struct resolve_method *method = find_method(state->methods[0]);
 101                 if (method) {
 102                         req = method->send_fn(&state->name, c->event_ctx);
 103                 }
 104                 if (req == NULL) state->methods++;
 105         } while (!req && state->methods[0]);
 106
 107         if (req) {
 108                 req->async.fn = resolve_handler;
 109                 req->async.private = c;
 110         }
 111
 112         return req;
 113 }
 114
 115 /*
 116   general name resolution - async send
 117  */
 118 struct composite_context *resolve_name_send(struct nbt_name *name, struct event_context *event_ctx)
 119 {
 120         struct composite_context *c;
 121         struct resolve_state *state;
 122         NTSTATUS status;
 123
 124         c = talloc_zero(NULL, struct composite_context);
 125         if (c == NULL) goto failed;
 126
 127         state = talloc(c, struct resolve_state);
 128         if (state == NULL) goto failed;
 129
 130         status = nbt_name_dup(state, name, &state->name);
 131         if (!NT_STATUS_IS_OK(status)) goto failed;
 132
 133         state->methods = lp_name_resolve_order();
 134         if (state->methods == NULL) {
 135                 return NULL;
 136         }
 137
 138         c->state = SMBCLI_REQUEST_SEND;
 139         c->private = state;
 140         if (event_ctx == NULL) {
 141                 c->event_ctx = event_context_init(c);
 142                 if (c->event_ctx == NULL) goto failed;
 143         } else {
 144                 c->event_ctx = talloc_reference(c, event_ctx);
 145         }
 146
 147         state->req = setup_next_method(c);
 148         if (state->req == NULL) goto failed;
 149
 150         return c;
 151
 152 failed:
 153         talloc_free(c);
 154         return NULL;
 155 }
 156
 157 /*
 158   general name resolution method - recv side
 159  */
 160 NTSTATUS resolve_name_recv(struct composite_context *c,
 161                            TALLOC_CTX *mem_ctx, const char **reply_addr)
 162 {
 163         NTSTATUS status;
 164
 165         status = composite_wait(c);
 166
 167         if (NT_STATUS_IS_OK(status)) {
 168                 struct resolve_state *state = talloc_get_type(c->private, struct resolve_state);
 169                 *reply_addr = talloc_steal(mem_ctx, state->reply_addr);
 170         }
 171
 172         talloc_free(c);
 173         return status;
 174 }
 175
 176 /*
 177   general name resolution - sync call
 178  */
 179 NTSTATUS resolve_name(struct nbt_name *name, TALLOC_CTX *mem_ctx, const char **reply_addr)
 180 {
 181         struct composite_context *c = resolve_name_send(name, NULL);
 182         return resolve_name_recv(c, mem_ctx, reply_addr);
 183 }