source4/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/composite/composite.h"
  26 #include "libcli/resolve/resolve.h"
  27 #include "librpc/gen_ndr/ndr_nbt.h"
  28
  29 struct resolve_state {
  30         struct nbt_name name;
  31         const char **methods;
  32         struct composite_context *creq;
  33         const char *reply_addr;
  34 };
  35
  36 static struct composite_context *setup_next_method(struct composite_context *c);
  37
  38 /* pointers to the resolver backends */
  39 static const struct resolve_method {
  40         const char *name;
  41         struct composite_context *(*send_fn)(struct nbt_name *, struct event_context *);
  42         NTSTATUS (*recv_fn)(struct composite_context *, TALLOC_CTX *, const char **);
  43
  44 } resolve_methods[] = {
  45         { "bcast", resolve_name_bcast_send,  resolve_name_bcast_recv },
  46         { "wins",  resolve_name_wins_send,   resolve_name_wins_recv },
  47         { "host",  resolve_name_host_send,   resolve_name_host_recv }
  48 };
  49
  50
  51 /*
  52    find a matching backend
  53 */
  54 static const struct resolve_method *find_method(const char *name)
  55 {
  56         int i;
  57         if (name == NULL) return NULL;
  58         for (i=0;i<ARRAY_SIZE(resolve_methods);i++) {
  59                 if (strcasecmp(name, resolve_methods[i].name) == 0) {
  60                         return &resolve_methods[i];
  61                 }
  62         }
  63         return NULL;
  64 }
  65
  66 /*
  67   handle completion of one name resolve method
  68 */
  69 static void resolve_handler(struct composite_context *creq)
  70 {
  71         struct composite_context *c = creq->async.private_data;
  72         struct resolve_state *state = talloc_get_type(c->private_data, struct resolve_state);
  73         const struct resolve_method *method = find_method(state->methods[0]);
  74
  75         c->status = method->recv_fn(creq, state, &state->reply_addr);
  76
  77         if (!NT_STATUS_IS_OK(c->status)) {
  78                 state->methods++;
  79                 state->creq = setup_next_method(c);
  80                 if (state->creq != NULL) {
  81                         return;
  82                 }
  83         }
  84
  85         if (!NT_STATUS_IS_OK(c->status)) {
  86                 c->state = COMPOSITE_STATE_ERROR;
  87         } else {
  88                 c->state = COMPOSITE_STATE_DONE;
  89         }
  90         if (c->async.fn) {
  91                 c->async.fn(c);
  92         }
  93 }
  94
  95
  96 static struct composite_context *setup_next_method(struct composite_context *c)
  97 {
  98         struct resolve_state *state = talloc_get_type(c->private_data, struct resolve_state);
  99         struct composite_context *creq = NULL;
 100
 101         do {
 102                 const struct resolve_method *method = find_method(state->methods[0]);
 103                 if (method) {
 104                         creq = method->send_fn(&state->name, c->event_ctx);
 105                 }
 106                 if (creq == NULL && state->methods[0]) state->methods++;
 107
 108         } while (!creq && state->methods[0]);
 109
 110         if (creq) {
 111                 creq->async.fn = resolve_handler;
 112                 creq->async.private_data = c;
 113         }
 114
 115         return creq;
 116 }
 117
 118 /*
 119   general name resolution - async send
 120  */
 121 struct composite_context *resolve_name_send(struct nbt_name *name, struct event_context *event_ctx,
 122                                             const char **methods)
 123 {
 124         struct composite_context *c;
 125         struct resolve_state *state;
 126         NTSTATUS status;
 127
 128         c = talloc_zero(NULL, struct composite_context);
 129         if (c == NULL) goto failed;
 130
 131         state = talloc(c, struct resolve_state);
 132         if (state == NULL) goto failed;
 133
 134         status = nbt_name_dup(state, name, &state->name);
 135         if (!NT_STATUS_IS_OK(status)) goto failed;
 136
 137         if (methods == NULL) goto failed;
 138         state->methods = str_list_copy(state, methods);
 139         if (state->methods == NULL) goto failed;
 140
 141         c->state = COMPOSITE_STATE_IN_PROGRESS;
 142         c->private_data = state;
 143
 144         if (event_ctx == NULL) {
 145                 c->event_ctx = event_context_init(c);
 146                 if (c->event_ctx == NULL) goto failed;
 147
 148         } else {
 149                 c->event_ctx = talloc_reference(c, event_ctx);
 150         }
 151
 152         if (is_ipaddress(state->name.name) ||
 153             strcasecmp(state->name.name, "localhost") == 0) {
 154                 struct ipv4_addr ip = interpret_addr2(state->name.name);
 155                 state->reply_addr = talloc_strdup(state, sys_inet_ntoa(ip));
 156                 if (!state->reply_addr) goto failed;
 157                 composite_done(c);
 158                 return c;
 159         }
 160
 161         state->creq = setup_next_method(c);
 162         if (state->creq == NULL) goto failed;
 163
 164         return c;
 165
 166 failed:
 167         talloc_free(c);
 168         return NULL;
 169 }
 170
 171 /*
 172   general name resolution method - recv side
 173  */
 174 NTSTATUS resolve_name_recv(struct composite_context *c,
 175                            TALLOC_CTX *mem_ctx, const char **reply_addr)
 176 {
 177         NTSTATUS status;
 178
 179         status = composite_wait(c);
 180
 181         if (NT_STATUS_IS_OK(status)) {
 182                 struct resolve_state *state = talloc_get_type(c->private_data, struct resolve_state);
 183                 *reply_addr = talloc_steal(mem_ctx, state->reply_addr);
 184         }
 185
 186         talloc_free(c);
 187         return status;
 188 }
 189
 190 /*
 191   general name resolution - sync call
 192  */
 193 NTSTATUS resolve_name(struct nbt_name *name, TALLOC_CTX *mem_ctx, const char **reply_addr,
 194                       struct event_context *ev)
 195 {
 196         struct composite_context *c = resolve_name_send(name, ev, lp_name_resolve_order());
 197         return resolve_name_recv(c, mem_ctx, reply_addr);
 198 }
 199
 200 /* Initialise a struct nbt_name with a NULL scope */
 201
 202 void make_nbt_name(struct nbt_name *nbt, const char *name, int type)
 203 {
 204         nbt->name = name;
 205         nbt->scope = NULL;
 206         nbt->type = type;
 207 }
 208
 209 /* Initialise a struct nbt_name with a NBT_NAME_CLIENT (0x00) name */
 210
 211 void make_nbt_name_client(struct nbt_name *nbt, const char *name)
 212 {
 213         make_nbt_name(nbt, name, NBT_NAME_CLIENT);
 214 }
 215
 216 /* Initialise a struct nbt_name with a NBT_NAME_SERVER (0x20) name */
 217
 218 void make_nbt_name_server(struct nbt_name *nbt, const char *name)
 219 {
 220         make_nbt_name(nbt, name, NBT_NAME_SERVER);
 221 }