source4/lib/socket/connect_multi.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Fire connect requests to a host and a number of ports, with a timeout
   5    between the connect request. Return if the first connect comes back
   6    successfully or return the last error.
   7
   8    Copyright (C) Volker Lendecke 2005
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "lib/socket/socket.h"
  26 #include "lib/events/events.h"
  27 #include "libcli/composite/composite.h"
  28 #include "libcli/resolve/resolve.h"
  29
  30 #define MULTI_PORT_DELAY 2000 /* microseconds */
  31
  32 /*
  33   overall state
  34 */
  35 struct connect_multi_state {
  36         const char *server_address;
  37         int num_ports;
  38         uint16_t *ports;
  39
  40         struct socket_context *sock;
  41         uint16_t result_port;
  42
  43         int num_connects_sent, num_connects_recv;
  44 };
  45
  46 /*
  47   state of an individual socket_connect_send() call
  48 */
  49 struct connect_one_state {
  50         struct composite_context *result;
  51         struct socket_context *sock;
  52         struct socket_address *addr;
  53 };
  54
  55 static void continue_resolve_name(struct composite_context *creq);
  56 static void connect_multi_timer(struct event_context *ev,
  57                                     struct timed_event *te,
  58                                     struct timeval tv, void *p);
  59 static void connect_multi_next_socket(struct composite_context *result);
  60 static void continue_one(struct composite_context *creq);
  61
  62 /*
  63   setup an async socket_connect, with multiple ports
  64 */
  65 _PUBLIC_ struct composite_context *socket_connect_multi_send(TALLOC_CTX *mem_ctx,
  66                                                     const char *server_address,
  67                                                     int num_server_ports,
  68                                                     uint16_t *server_ports,
  69                                                     struct event_context *event_ctx)
  70 {
  71         struct composite_context *result;
  72         struct connect_multi_state *multi;
  73         int i;
  74
  75         result = talloc_zero(mem_ctx, struct composite_context);
  76         if (result == NULL) return NULL;
  77         result->state = COMPOSITE_STATE_IN_PROGRESS;
  78         result->event_ctx = event_ctx;
  79
  80         multi = talloc_zero(result, struct connect_multi_state);
  81         if (composite_nomem(multi, result)) goto failed;
  82         result->private_data = multi;
  83
  84         multi->server_address = talloc_strdup(multi, server_address);
  85         if (composite_nomem(multi->server_address, result)) goto failed;
  86
  87         multi->num_ports = num_server_ports;
  88         multi->ports = talloc_array(multi, uint16_t, multi->num_ports);
  89         if (composite_nomem(multi->ports, result)) goto failed;
  90
  91         for (i=0; i<multi->num_ports; i++) {
  92                 multi->ports[i] = server_ports[i];
  93         }
  94
  95         if (!is_ipaddress(server_address)) {
  96                 /*
  97                     we don't want to do the name resolution separately
  98                     for each port, so start it now, then only start on
  99                     the real sockets once we have an IP
 100                  */
 101                 struct nbt_name name;
 102                 struct composite_context *creq;
 103                 make_nbt_name_client(&name, server_address);
 104                 creq = resolve_name_send(&name, result->event_ctx,
 105                                          lp_name_resolve_order());
 106                 if (composite_nomem(creq, result)) goto failed;
 107                 composite_continue(result, creq, continue_resolve_name, result);
 108                 return result;
 109         }
 110
 111         /* now we've setup the state we can process the first socket */
 112         connect_multi_next_socket(result);
 113
 114         if (!NT_STATUS_IS_OK(result->status)) {
 115                 goto failed;
 116         }
 117
 118         return result;
 119
 120  failed:
 121         composite_error(result, result->status);
 122         return result;
 123 }
 124
 125 /*
 126   start connecting to the next socket/port in the list
 127 */
 128 static void connect_multi_next_socket(struct composite_context *result)
 129 {
 130         struct connect_multi_state *multi = talloc_get_type(result->private_data,
 131                                                             struct connect_multi_state);
 132         struct connect_one_state *state;
 133         struct composite_context *creq;
 134         int next = multi->num_connects_sent;
 135
 136         if (next == multi->num_ports) {
 137                 /* don't do anything, just wait for the existing ones to finish */
 138                 return;
 139         }
 140
 141         multi->num_connects_sent += 1;
 142
 143         state = talloc(multi, struct connect_one_state);
 144         if (composite_nomem(state, result)) return;
 145
 146         state->result = result;
 147         result->status = socket_create("ipv4", SOCKET_TYPE_STREAM, &state->sock, 0);
 148         if (!composite_is_ok(result)) return;
 149
 150         /* Form up the particular address we are interested in */
 151         state->addr = socket_address_from_strings(state, state->sock->backend_name,
 152                                                   multi->server_address, multi->ports[next]);
 153         if (composite_nomem(state->addr, result)) return;
 154
 155         talloc_steal(state, state->sock);
 156
 157         creq = socket_connect_send(state->sock, NULL,
 158                                    state->addr, 0, result->event_ctx);
 159         if (composite_nomem(creq, result)) return;
 160         talloc_steal(state, creq);
 161
 162         composite_continue(result, creq, continue_one, state);
 163
 164         /* if there are more ports to go then setup a timer to fire when we have waited
 165            for a couple of milli-seconds, when that goes off we try the next port regardless
 166            of whether this port has completed */
 167         if (multi->num_ports > multi->num_connects_sent) {
 168                 /* note that this timer is a child of the single
 169                    connect attempt state, so it will go away when this
 170                    request completes */
 171                 event_add_timed(result->event_ctx, state,
 172                                 timeval_current_ofs(0, MULTI_PORT_DELAY),
 173                                 connect_multi_timer, result);
 174         }
 175 }
 176
 177 /*
 178   a timer has gone off telling us that we should try the next port
 179 */
 180 static void connect_multi_timer(struct event_context *ev,
 181                                 struct timed_event *te,
 182                                 struct timeval tv, void *p)
 183 {
 184         struct composite_context *result = talloc_get_type(p, struct composite_context);
 185         connect_multi_next_socket(result);
 186 }
 187
 188
 189 /*
 190   recv name resolution reply then send the next connect
 191 */
 192 static void continue_resolve_name(struct composite_context *creq)
 193 {
 194         struct composite_context *result = talloc_get_type(creq->async.private_data,
 195                                                            struct composite_context);
 196         struct connect_multi_state *multi = talloc_get_type(result->private_data,
 197                                                             struct connect_multi_state);
 198         const char *addr;
 199
 200         result->status = resolve_name_recv(creq, multi, &addr);
 201         if (!composite_is_ok(result)) return;
 202
 203         multi->server_address = addr;
 204
 205         connect_multi_next_socket(result);
 206 }
 207
 208 /*
 209   one of our socket_connect_send() calls hash finished. If it got a
 210   connection or there are none left then we are done
 211 */
 212 static void continue_one(struct composite_context *creq)
 213 {
 214         struct connect_one_state *state = talloc_get_type(creq->async.private_data,
 215                                                           struct connect_one_state);
 216         struct composite_context *result = state->result;
 217         struct connect_multi_state *multi = talloc_get_type(result->private_data,
 218                                                             struct connect_multi_state);
 219         NTSTATUS status;
 220         multi->num_connects_recv++;
 221
 222         status = socket_connect_recv(creq);
 223
 224         if (NT_STATUS_IS_OK(status)) {
 225                 multi->sock = talloc_steal(multi, state->sock);
 226                 multi->result_port = state->addr->port;
 227         }
 228
 229         talloc_free(state);
 230
 231         if (NT_STATUS_IS_OK(status) ||
 232             multi->num_connects_recv == multi->num_ports) {
 233                 result->status = status;
 234                 composite_done(result);
 235                 return;
 236         }
 237
 238         /* try the next port */
 239         connect_multi_next_socket(result);
 240 }
 241
 242 /*
 243   async recv routine for socket_connect_multi()
 244  */
 245 _PUBLIC_ NTSTATUS socket_connect_multi_recv(struct composite_context *ctx,
 246                                    TALLOC_CTX *mem_ctx,
 247                                    struct socket_context **sock,
 248                                    uint16_t *port)
 249 {
 250         NTSTATUS status = composite_wait(ctx);
 251         if (NT_STATUS_IS_OK(status)) {
 252                 struct connect_multi_state *multi =
 253                         talloc_get_type(ctx->private_data,
 254                                         struct connect_multi_state);
 255                 *sock = talloc_steal(mem_ctx, multi->sock);
 256                 *port = multi->result_port;
 257         }
 258         talloc_free(ctx);
 259         return status;
 260 }
 261
 262 NTSTATUS socket_connect_multi(TALLOC_CTX *mem_ctx,
 263                               const char *server_address,
 264                               int num_server_ports, uint16_t *server_ports,
 265                               struct event_context *event_ctx,
 266                               struct socket_context **result,
 267                               uint16_t *result_port)
 268 {
 269         struct composite_context *ctx =
 270                 socket_connect_multi_send(mem_ctx, server_address,
 271                                           num_server_ports, server_ports,
 272                                           event_ctx);
 273         return socket_connect_multi_recv(ctx, mem_ctx, result, result_port);
 274 }