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
  27 struct resolve_state {
  28         struct nbt_name name;
  29         const char **methods;
  30         struct composite_context *creq;
  31         const char *reply_addr;
  32 };
  33
  34 static struct composite_context *setup_next_method(struct composite_context *c);
  35
  36 /* pointers to the resolver backends */
  37 static const struct resolve_method {
  38         const char *name;
  39         struct composite_context *(*send_fn)(struct nbt_name *, struct event_context *);
  40         NTSTATUS (*recv_fn)(struct composite_context *, TALLOC_CTX *, const char **);
  41
  42 } resolve_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(resolve_methods);i++) {
  57                 if (strcasecmp(name, resolve_methods[i].name) == 0) {
  58                         return &resolve_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 *creq)
  68 {
  69         struct composite_context *c = creq->async.private_data;
  70         struct resolve_state *state = talloc_get_type(c->private_data, struct resolve_state);
  71         const struct resolve_method *method = find_method(state->methods[0]);
  72
  73         c->status = method->recv_fn(creq, state, &state->reply_addr);
  74
  75         if (!NT_STATUS_IS_OK(c->status)) {
  76                 state->methods++;
  77                 state->creq = setup_next_method(c);
  78                 if (state->creq != NULL) {
  79                         return;
  80                 }
  81         }
  82
  83         if (!NT_STATUS_IS_OK(c->status)) {
  84                 c->state = COMPOSITE_STATE_ERROR;
  85         } else {
  86                 c->state = COMPOSITE_STATE_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_data, struct resolve_state);
  97         struct composite_context *creq = NULL;
  98
  99         do {
 100                 const struct resolve_method *method = find_method(state->methods[0]);
 101                 if (method) {
 102                         creq = method->send_fn(&state->name, c->event_ctx);
 103                 }
 104                 if (creq == NULL && state->methods[0]) state->methods++;
 105
 106         } while (!creq && state->methods[0]);
 107
 108         if (creq) {
 109                 creq->async.fn = resolve_handler;
 110                 creq->async.private_data = c;
 111         }
 112
 113         return creq;
 114 }
 115
 116 /*
 117   general name resolution - async send
 118  */
 119 struct composite_context *resolve_name_send(struct nbt_name *name, struct event_context *event_ctx,
 120                                             const char **methods)
 121 {
 122         struct composite_context *c;
 123         struct resolve_state *state;
 124         NTSTATUS status;
 125
 126         c = talloc_zero(NULL, struct composite_context);
 127         if (c == NULL) goto failed;
 128
 129         state = talloc(c, struct resolve_state);
 130         if (state == NULL) goto failed;
 131
 132         status = nbt_name_dup(state, name, &state->name);
 133         if (!NT_STATUS_IS_OK(status)) goto failed;
 134
 135         if (methods == NULL) goto failed;
 136         state->methods = str_list_copy(state, methods);
 137         if (state->methods == NULL) goto failed;
 138
 139         c->state = COMPOSITE_STATE_IN_PROGRESS;
 140         c->private_data = state;
 141
 142         if (event_ctx == NULL) {
 143                 c->event_ctx = event_context_init(c);
 144                 if (c->event_ctx == NULL) goto failed;
 145
 146         } else {
 147                 c->event_ctx = talloc_reference(c, event_ctx);
 148         }
 149
 150         if (is_ipaddress(state->name.name) ||
 151             strcasecmp(state->name.name, "localhost") == 0) {
 152                 struct ipv4_addr ip = interpret_addr2(state->name.name);
 153                 state->reply_addr = talloc_strdup(state, sys_inet_ntoa(ip));
 154                 if (!state->reply_addr) goto failed;
 155                 composite_done(c);
 156                 return c;
 157         }
 158
 159         state->creq = setup_next_method(c);
 160         if (state->creq == NULL) goto failed;
 161
 162         return c;
 163
 164 failed:
 165         talloc_free(c);
 166         return NULL;
 167 }
 168
 169 /*
 170   general name resolution method - recv side
 171  */
 172 NTSTATUS resolve_name_recv(struct composite_context *c,
 173                            TALLOC_CTX *mem_ctx, const char **reply_addr)
 174 {
 175         NTSTATUS status;
 176
 177         status = composite_wait(c);
 178
 179         if (NT_STATUS_IS_OK(status)) {
 180                 struct resolve_state *state = talloc_get_type(c->private_data, struct resolve_state);
 181                 *reply_addr = talloc_steal(mem_ctx, state->reply_addr);
 182         }
 183
 184         talloc_free(c);
 185         return status;
 186 }
 187
 188 /*
 189   general name resolution - sync call
 190  */
 191 NTSTATUS resolve_name(struct nbt_name *name, TALLOC_CTX *mem_ctx, const char **reply_addr,
 192                       struct event_context *ev)
 193 {
 194         struct composite_context *c = resolve_name_send(name, ev, lp_name_resolve_order());
 195         return resolve_name_recv(c, mem_ctx, reply_addr);
 196 }
 197
 198 /* Initialise a struct nbt_name with a NULL scope */
 199
 200 void make_nbt_name(struct nbt_name *nbt, const char *name, int type)
 201 {
 202         nbt->name = name;
 203         nbt->scope = NULL;
 204         nbt->type = type;
 205 }
 206
 207 /* Initialise a struct nbt_name with a NBT_NAME_CLIENT (0x00) name */
 208
 209 void make_nbt_name_client(struct nbt_name *nbt, const char *name)
 210 {
 211         make_nbt_name(nbt, name, NBT_NAME_CLIENT);
 212 }
 213
 214 /* Initialise a struct nbt_name with a NBT_NAME_SERVER (0x20) name */
 215
 216 void make_nbt_name_server(struct nbt_name *nbt, const char *name)
 217 {
 218         make_nbt_name(nbt, name, NBT_NAME_SERVER);
 219 }