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