www.tinc-vpn.org Git - tinc/blob - src/protocol.c

   1 /*
   2     protocol.c -- handle the meta-protocol, basic functions
   3     Copyright (C) 1999-2001 Ivo Timmermans <ivo@o2w.nl>,
   4                   2000,2001 Guus Sliepen <guus@sliepen.eu.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id: protocol.c,v 1.28.4.148 2003/11/17 15:30:17 guus Exp $
  21 */
  22
  23 #include "system.h"
  24
  25 #include "conf.h"
  26 #include "connection.h"
  27 #include "logger.h"
  28 #include "meta.h"
  29 #include "protocol.h"
  30 #include "utils.h"
  31 #include "xalloc.h"
  32
  33 bool tunnelserver = false;
  34
  35 /* Jumptable for the request handlers */
  36
  37 static bool (*request_handlers[])(connection_t *) = {
  38                 id_h, metakey_h, challenge_h, chal_reply_h, ack_h,
  39                 status_h, error_h, termreq_h,
  40                 ping_h, pong_h,
  41                 add_subnet_h, del_subnet_h,
  42                 add_edge_h, del_edge_h,
  43                 key_changed_h, req_key_h, ans_key_h, tcppacket_h,
  44 };
  45
  46 /* Request names */
  47
  48 static char (*request_name[]) = {
  49                 "ID", "METAKEY", "CHALLENGE", "CHAL_REPLY", "ACK",
  50                 "STATUS", "ERROR", "TERMREQ",
  51                 "PING", "PONG",
  52                 "ADD_SUBNET", "DEL_SUBNET",
  53                 "ADD_EDGE", "DEL_EDGE", "KEY_CHANGED", "REQ_KEY", "ANS_KEY", "PACKET",
  54 };
  55
  56 static avl_tree_t *past_request_tree;
  57
  58 bool check_id(const char *id)
  59 {
  60         for(; *id; id++)
  61                 if(!isalnum(*id) && *id != '_')
  62                         return false;
  63
  64         return true;
  65 }
  66
  67 /* Generic request routines - takes care of logging and error
  68    detection as well */
  69
  70 bool send_request(connection_t *c, const char *format, ...)
  71 {
  72         va_list args;
  73         char buffer[MAXBUFSIZE];
  74         int len, request;
  75
  76         cp();
  77
  78         /* Use vsnprintf instead of vasprintf: faster, no memory
  79            fragmentation, cleanup is automatic, and there is a limit on the
  80            input buffer anyway */
  81
  82         va_start(args, format);
  83         len = vsnprintf(buffer, MAXBUFSIZE, format, args);
  84         va_end(args);
  85
  86         if(len < 0 || len > MAXBUFSIZE - 1) {
  87                 logger(LOG_ERR, _("Output buffer overflow while sending request to %s (%s)"),
  88                            c->name, c->hostname);
  89                 return false;
  90         }
  91
  92         ifdebug(PROTOCOL) {
  93                 sscanf(buffer, "%d", &request);
  94                 ifdebug(META)
  95                         logger(LOG_DEBUG, _("Sending %s to %s (%s): %s"),
  96                                    request_name[request], c->name, c->hostname, buffer);
  97                 else
  98                         logger(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request],
  99                                    c->name, c->hostname);
 100         }
 101
 102         buffer[len++] = '\n';
 103
 104         if(c == broadcast) {
 105                 broadcast_meta(NULL, buffer, len);
 106                 return true;
 107         } else
 108                 return send_meta(c, buffer, len);
 109 }
 110
 111 void forward_request(connection_t *from)
 112 {
 113         int request;
 114
 115         cp();
 116
 117         ifdebug(PROTOCOL) {
 118                 sscanf(from->buffer, "%d", &request);
 119                 ifdebug(META)
 120                         logger(LOG_DEBUG, _("Forwarding %s from %s (%s): %s"),
 121                                    request_name[request], from->name, from->hostname,
 122                                    from->buffer);
 123                 else
 124                         logger(LOG_DEBUG, _("Forwarding %s from %s (%s)"),
 125                                    request_name[request], from->name, from->hostname);
 126         }
 127
 128         from->buffer[from->reqlen - 1] = '\n';
 129
 130         broadcast_meta(from, from->buffer, from->reqlen);
 131 }
 132
 133 bool receive_request(connection_t *c)
 134 {
 135         int request;
 136
 137         cp();
 138
 139         if(sscanf(c->buffer, "%d", &request) == 1) {
 140                 if((request < 0) || (request >= LAST) || !request_handlers[request]) {
 141                         ifdebug(META)
 142                                 logger(LOG_DEBUG, _("Unknown request from %s (%s): %s"),
 143                                            c->name, c->hostname, c->buffer);
 144                         else
 145                                 logger(LOG_ERR, _("Unknown request from %s (%s)"),
 146                                            c->name, c->hostname);
 147
 148                         return false;
 149                 } else {
 150                         ifdebug(PROTOCOL) {
 151                                 ifdebug(META)
 152                                         logger(LOG_DEBUG, _("Got %s from %s (%s): %s"),
 153                                                    request_name[request], c->name, c->hostname,
 154                                                    c->buffer);
 155                                 else
 156                                         logger(LOG_DEBUG, _("Got %s from %s (%s)"),
 157                                                    request_name[request], c->name, c->hostname);
 158                         }
 159                 }
 160
 161                 if((c->allow_request != ALL) && (c->allow_request != request)) {
 162                         logger(LOG_ERR, _("Unauthorized request from %s (%s)"), c->name,
 163                                    c->hostname);
 164                         return false;
 165                 }
 166
 167                 if(!request_handlers[request](c)) {
 168                         /* Something went wrong. Probably scriptkiddies. Terminate. */
 169
 170                         logger(LOG_ERR, _("Error while processing %s from %s (%s)"),
 171                                    request_name[request], c->name, c->hostname);
 172                         return false;
 173                 }
 174         } else {
 175                 logger(LOG_ERR, _("Bogus data received from %s (%s)"),
 176                            c->name, c->hostname);
 177                 return false;
 178         }
 179
 180         return true;
 181 }
 182
 183 static int past_request_compare(const past_request_t *a, const past_request_t *b)
 184 {
 185         return strcmp(a->request, b->request);
 186 }
 187
 188 static void free_past_request(past_request_t *r)
 189 {
 190         cp();
 191
 192         if(r->request)
 193                 free(r->request);
 194
 195         free(r);
 196 }
 197
 198 void init_requests(void)
 199 {
 200         cp();
 201
 202         past_request_tree = avl_alloc_tree((avl_compare_t) past_request_compare, (avl_action_t) free_past_request);
 203 }
 204
 205 void exit_requests(void)
 206 {
 207         cp();
 208
 209         avl_delete_tree(past_request_tree);
 210 }
 211
 212 bool seen_request(char *request)
 213 {
 214         past_request_t *new, p = {0};
 215
 216         cp();
 217
 218         p.request = request;
 219
 220         if(avl_search(past_request_tree, &p)) {
 221                 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Already seen request"));
 222                 return true;
 223         } else {
 224                 new = xmalloc(sizeof(*new));
 225                 new->request = xstrdup(request);
 226                 new->firstseen = now;
 227                 avl_insert(past_request_tree, new);
 228                 return false;
 229         }
 230 }
 231
 232 void age_past_requests(void)
 233 {
 234         avl_node_t *node, *next;
 235         past_request_t *p;
 236         int left = 0, deleted = 0;
 237
 238         cp();
 239
 240         for(node = past_request_tree->head; node; node = next) {
 241                 next = node->next;
 242                 p = node->data;
 243
 244                 if(p->firstseen + pingtimeout < now)
 245                         avl_delete_node(past_request_tree, node), deleted++;
 246                 else
 247                         left++;
 248         }
 249
 250         if(left || deleted)
 251                 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Aging past requests: deleted %d, left %d"),
 252                            deleted, left);
 253 }