source/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(
  66                                                     TALLOC_CTX *mem_ctx,
  67                                                     const char *server_address,
  68                                                     int num_server_ports,
  69                                                     uint16_t *server_ports,
  70                                                     struct event_context *event_ctx)
  71 {
  72         struct composite_context *result;
  73         struct connect_multi_state *multi;
  74         int i;
  75
  76         result = talloc_zero(mem_ctx, struct composite_context);
  77         if (result == NULL) return NULL;
  78         result->state = COMPOSITE_STATE_IN_PROGRESS;
  79         result->event_ctx = event_ctx;
  80
  81         multi = talloc_zero(result, struct connect_multi_state);
  82         if (composite_nomem(multi, result)) goto failed;
  83         result->private_data = multi;
  84
  85         multi->server_address = talloc_strdup(multi, server_address);
  86         if (composite_nomem(multi->server_address, result)) goto failed;
  87
  88         multi->num_ports = num_server_ports;
  89         multi->ports = talloc_array(multi, uint16_t, multi->num_ports);
  90         if (composite_nomem(multi->ports, result)) goto failed;
  91
  92         for (i=0; i<multi->num_ports; i++) {
  93                 multi->ports[i] = server_ports[i];
  94         }
  95
  96         if (!is_ipaddress(server_address)) {
  97                 /*
  98                     we don't want to do the name resolution separately
  99                     for each port, so start it now, then only start on
 100                     the real sockets once we have an IP
 101                  */
 102                 struct nbt_name name;
 103                 struct composite_context *creq;
 104                 make_nbt_name_client(&name, server_address);
 105                 creq = resolve_name_send(&name, result->event_ctx,
 106                                          lp_name_resolve_order());
 107                 if (composite_nomem(creq, result)) goto failed;
 108                 composite_continue(result, creq, continue_resolve_name, result);
 109                 return result;
 110         }
 111
 112         /* now we've setup the state we can process the first socket */
 113         connect_multi_next_socket(result);
 114
 115         if (!NT_STATUS_IS_OK(result->status)) {
 116                 goto failed;
 117         }
 118
 119         return result;
 120
 121  failed:
 122         composite_error(result, result->status);
 123         return result;
 124 }
 125
 126 /*
 127   start connecting to the next socket/port in the list
 128 */
 129 static void connect_multi_next_socket(struct composite_context *result)
 130 {
 131         struct connect_multi_state *multi = talloc_get_type(result->private_data,
 132                                                             struct connect_multi_state);
 133         struct connect_one_state *state;
 134         struct composite_context *creq;
 135         int next = multi->num_connects_sent;
 136
 137         if (next == multi->num_ports) {
 138                 /* don't do anything, just wait for the existing ones to finish */
 139                 return;
 140         }
 141
 142         multi->num_connects_sent += 1;
 143
 144         state = talloc(multi, struct connect_one_state);
 145         if (composite_nomem(state, result)) return;
 146
 147         state->result = result;
 148         result->status = socket_create("ipv4", SOCKET_TYPE_STREAM, &state->sock, 0);
 149         if (!composite_is_ok(result)) return;
 150
 151         /* Form up the particular address we are interested in */
 152         state->addr = socket_address_from_strings(state, state->sock->backend_name,
 153                                                   multi->server_address, multi->ports[next]);
 154         if (composite_nomem(state->addr, result)) return;
 155
 156         talloc_steal(state, state->sock);
 157
 158         creq = socket_connect_send(state->sock, NULL,
 159                                    state->addr, 0, result->event_ctx);
 160         if (composite_nomem(creq, result)) return;
 161         talloc_steal(state, creq);
 162
 163         composite_continue(result, creq, continue_one, state);
 164
 165         /* if there are more ports to go then setup a timer to fire when we have waited
 166            for a couple of milli-seconds, when that goes off we try the next port regardless
 167            of whether this port has completed */
 168         if (multi->num_ports > multi->num_connects_sent) {
 169                 /* note that this timer is a child of the single
 170                    connect attempt state, so it will go away when this
 171                    request completes */
 172                 event_add_timed(result->event_ctx, state,
 173                                 timeval_current_ofs(0, MULTI_PORT_DELAY),
 174                                 connect_multi_timer, result);
 175         }
 176 }
 177
 178 /*
 179   a timer has gone off telling us that we should try the next port
 180 */
 181 static void connect_multi_timer(struct event_context *ev,
 182                                 struct timed_event *te,
 183                                 struct timeval tv, void *p)
 184 {
 185         struct composite_context *result = talloc_get_type(p, struct composite_context);
 186         connect_multi_next_socket(result);
 187 }
 188
 189
 190 /*
 191   recv name resolution reply then send the next connect
 192 */
 193 static void continue_resolve_name(struct composite_context *creq)
 194 {
 195         struct composite_context *result = talloc_get_type(creq->async.private_data,
 196                                                            struct composite_context);
 197         struct connect_multi_state *multi = talloc_get_type(result->private_data,
 198                                                             struct connect_multi_state);
 199         const char *addr;
 200
 201         result->status = resolve_name_recv(creq, multi, &addr);
 202         if (!composite_is_ok(result)) return;
 203
 204         multi->server_address = addr;
 205
 206         connect_multi_next_socket(result);
 207 }
 208
 209 /*
 210   one of our socket_connect_send() calls hash finished. If it got a
 211   connection or there are none left then we are done
 212 */
 213 static void continue_one(struct composite_context *creq)
 214 {
 215         struct connect_one_state *state = talloc_get_type(creq->async.private_data,
 216                                                           struct connect_one_state);
 217         struct composite_context *result = state->result;
 218         struct connect_multi_state *multi = talloc_get_type(result->private_data,
 219                                                             struct connect_multi_state);
 220         NTSTATUS status;
 221         multi->num_connects_recv++;
 222
 223         status = socket_connect_recv(creq);
 224
 225         if (NT_STATUS_IS_OK(status)) {
 226                 multi->sock = talloc_steal(multi, state->sock);
 227                 multi->result_port = state->addr->port;
 228         }
 229
 230         talloc_free(state);
 231
 232         if (NT_STATUS_IS_OK(status) ||
 233             multi->num_connects_recv == multi->num_ports) {
 234                 result->status = status;
 235                 composite_done(result);
 236                 return;
 237         }
 238
 239         /* try the next port */
 240         connect_multi_next_socket(result);
 241 }
 242
 243 /*
 244   async recv routine for socket_connect_multi()
 245  */
 246 _PUBLIC_ NTSTATUS socket_connect_multi_recv(struct composite_context *ctx,
 247                                    TALLOC_CTX *mem_ctx,
 248                                    struct socket_context **sock,
 249                                    uint16_t *port)
 250 {
 251         NTSTATUS status = composite_wait(ctx);
 252         if (NT_STATUS_IS_OK(status)) {
 253                 struct connect_multi_state *multi =
 254                         talloc_get_type(ctx->private_data,
 255                                         struct connect_multi_state);
 256                 *sock = talloc_steal(mem_ctx, multi->sock);
 257                 *port = multi->result_port;
 258         }
 259         talloc_free(ctx);
 260         return status;
 261 }
 262
 263 NTSTATUS socket_connect_multi(TALLOC_CTX *mem_ctx,
 264                               const char *server_address,
 265                               int num_server_ports, uint16_t *server_ports,
 266                               struct event_context *event_ctx,
 267                               struct socket_context **result,
 268                               uint16_t *result_port)
 269 {
 270         struct composite_context *ctx =
 271                 socket_connect_multi_send(mem_ctx, server_address,
 272                                           num_server_ports, server_ports,
 273                                           event_ctx);
 274         return socket_connect_multi_recv(ctx, mem_ctx, result, result_port);
 275 }