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 2 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, write to the Free Software
  22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include "includes.h"
  26 #include "lib/socket/socket.h"
  27 #include "lib/events/events.h"
  28 #include "libcli/composite/composite.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         uint16_t port;
  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 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         state->port = multi->ports[next];
 148
 149         result->status = socket_create("ipv4", SOCKET_TYPE_STREAM, &state->sock, 0);
 150         if (!composite_is_ok(result)) return;
 151
 152         talloc_steal(state, state->sock);
 153
 154         creq = socket_connect_send(state->sock, NULL, 0,
 155                                    multi->server_address, state->port, 0, result->event_ctx);
 156         if (composite_nomem(creq, result)) return;
 157         talloc_steal(state, creq);
 158
 159         composite_continue(result, creq, continue_one, state);
 160
 161         /* if there are more ports to go then setup a timer to fire when we have waited
 162            for a couple of milli-seconds, when that goes off we try the next port regardless
 163            of whether this port has completed */
 164         if (multi->num_ports > multi->num_connects_sent) {
 165                 /* note that this timer is a child of the single
 166                    connect attempt state, so it will go away when this
 167                    request completes */
 168                 event_add_timed(result->event_ctx, state,
 169                                 timeval_current_ofs(0, MULTI_PORT_DELAY),
 170                                 connect_multi_timer, result);
 171         }
 172 }
 173
 174 /*
 175   a timer has gone off telling us that we should try the next port
 176 */
 177 static void connect_multi_timer(struct event_context *ev,
 178                                 struct timed_event *te,
 179                                 struct timeval tv, void *p)
 180 {
 181         struct composite_context *result = talloc_get_type(p, struct composite_context);
 182         connect_multi_next_socket(result);
 183 }
 184
 185
 186 /*
 187   recv name resolution reply then send the next connect
 188 */
 189 static void continue_resolve_name(struct composite_context *creq)
 190 {
 191         struct composite_context *result = talloc_get_type(creq->async.private_data,
 192                                                            struct composite_context);
 193         struct connect_multi_state *multi = talloc_get_type(result->private_data,
 194                                                             struct connect_multi_state);
 195         const char *addr;
 196
 197         result->status = resolve_name_recv(creq, multi, &addr);
 198         if (!composite_is_ok(result)) return;
 199
 200         multi->server_address = addr;
 201
 202         connect_multi_next_socket(result);
 203 }
 204
 205 /*
 206   one of our socket_connect_send() calls hash finished. If it got a
 207   connection or there are none left then we are done
 208 */
 209 static void continue_one(struct composite_context *creq)
 210 {
 211         struct connect_one_state *state = talloc_get_type(creq->async.private_data,
 212                                                           struct connect_one_state);
 213         struct composite_context *result = state->result;
 214         struct connect_multi_state *multi = talloc_get_type(result->private_data,
 215                                                             struct connect_multi_state);
 216         NTSTATUS status;
 217         multi->num_connects_recv++;
 218
 219         status = socket_connect_recv(creq);
 220
 221         if (NT_STATUS_IS_OK(status)) {
 222                 multi->sock = talloc_steal(multi, state->sock);
 223                 multi->result_port = state->port;
 224         }
 225
 226         talloc_free(state);
 227
 228         if (NT_STATUS_IS_OK(status) ||
 229             multi->num_connects_recv == multi->num_ports) {
 230                 result->status = status;
 231                 composite_done(result);
 232                 return;
 233         }
 234
 235         /* try the next port */
 236         connect_multi_next_socket(result);
 237 }
 238
 239 /*
 240   async recv routine for socket_connect_multi()
 241  */
 242 NTSTATUS socket_connect_multi_recv(struct composite_context *ctx,
 243                                    TALLOC_CTX *mem_ctx,
 244                                    struct socket_context **sock,
 245                                    uint16_t *port)
 246 {
 247         NTSTATUS status = composite_wait(ctx);
 248         if (NT_STATUS_IS_OK(status)) {
 249                 struct connect_multi_state *multi =
 250                         talloc_get_type(ctx->private_data,
 251                                         struct connect_multi_state);
 252                 *sock = talloc_steal(mem_ctx, multi->sock);
 253                 *port = multi->result_port;
 254         }
 255         talloc_free(ctx);
 256         return status;
 257 }
 258
 259 NTSTATUS socket_connect_multi(TALLOC_CTX *mem_ctx,
 260                               const char *server_address,
 261                               int num_server_ports, uint16_t *server_ports,
 262                               struct event_context *event_ctx,
 263                               struct socket_context **result,
 264                               uint16_t *result_port)
 265 {
 266         struct composite_context *ctx =
 267                 socket_connect_multi_send(mem_ctx, server_address,
 268                                           num_server_ports, server_ports,
 269                                           event_ctx);
 270         return socket_connect_multi_recv(ctx, mem_ctx, result, result_port);
 271 }