git.meshlink.io Git - meshlink/blob - src/protocol.c

   1 /*
   2     protocol.c -- handle the meta-protocol, basic functions
   3     Copyright (C) 1999-2005 Ivo Timmermans,
   4                   2000-2006 Guus Sliepen <guus@tinc-vpn.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     $Id$
  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 *, char *) = {
  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 splay_tree_t *past_request_tree;
  57
  58 bool check_id(const char *id) {
  59         for(; *id; id++)
  60                 if(!isalnum(*id) && *id != '_')
  61                         return false;
  62
  63         return true;
  64 }
  65
  66 /* Generic request routines - takes care of logging and error
  67    detection as well */
  68
  69 bool send_request(connection_t *c, const char *format, ...) {
  70         va_list args;
  71         char request[MAXBUFSIZE];
  72         int len;
  73
  74         cp();
  75
  76         /* Use vsnprintf instead of vxasprintf: faster, no memory
  77            fragmentation, cleanup is automatic, and there is a limit on the
  78            input buffer anyway */
  79
  80         va_start(args, format);
  81         len = vsnprintf(request, MAXBUFSIZE, format, args);
  82         va_end(args);
  83
  84         if(len < 0 || len > MAXBUFSIZE - 1) {
  85                 logger(LOG_ERR, _("Output buffer overflow while sending request to %s (%s)"),
  86                            c->name, c->hostname);
  87                 return false;
  88         }
  89
  90         ifdebug(PROTOCOL) {
  91                 ifdebug(META)
  92                         logger(LOG_DEBUG, _("Sending %s to %s (%s): %s"),
  93                                    request_name[atoi(request)], c->name, c->hostname, request);
  94                 else
  95                         logger(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[atoi(request)],
  96                                    c->name, c->hostname);
  97         }
  98
  99         request[len++] = '\n';
 100
 101         if(c == broadcast) {
 102                 broadcast_meta(NULL, request, len);
 103                 return true;
 104         } else
 105                 return send_meta(c, request, len);
 106 }
 107
 108 void forward_request(connection_t *from, char *request) {
 109         cp();
 110
 111         ifdebug(PROTOCOL) {
 112                 ifdebug(META)
 113                         logger(LOG_DEBUG, _("Forwarding %s from %s (%s): %s"),
 114                                    request_name[atoi(request)], from->name, from->hostname, request);
 115                 else
 116                         logger(LOG_DEBUG, _("Forwarding %s from %s (%s)"),
 117                                    request_name[atoi(request)], from->name, from->hostname);
 118         }
 119
 120         int len = strlen(request);
 121         request[len] = '\n';
 122         broadcast_meta(from, request, len);
 123 }
 124
 125 bool receive_request(connection_t *c, char *request) {
 126         int reqno = atoi(request);
 127
 128         cp();
 129
 130         if(reqno || *request == '0') {
 131                 if((reqno < 0) || (reqno >= LAST) || !request_handlers[reqno]) {
 132                         ifdebug(META)
 133                                 logger(LOG_DEBUG, _("Unknown request from %s (%s): %s"),
 134                                            c->name, c->hostname, request);
 135                         else
 136                                 logger(LOG_ERR, _("Unknown request from %s (%s)"),
 137                                            c->name, c->hostname);
 138
 139                         return false;
 140                 } else {
 141                         ifdebug(PROTOCOL) {
 142                                 ifdebug(META)
 143                                         logger(LOG_DEBUG, _("Got %s from %s (%s): %s"),
 144                                                    request_name[reqno], c->name, c->hostname, request);
 145                                 else
 146                                         logger(LOG_DEBUG, _("Got %s from %s (%s)"),
 147                                                    request_name[reqno], c->name, c->hostname);
 148                         }
 149                 }
 150
 151                 if((c->allow_request != ALL) && (c->allow_request != reqno)) {
 152                         logger(LOG_ERR, _("Unauthorized request from %s (%s)"), c->name,
 153                                    c->hostname);
 154                         return false;
 155                 }
 156
 157                 if(!request_handlers[reqno](c, request)) {
 158                         /* Something went wrong. Probably scriptkiddies. Terminate. */
 159
 160                         logger(LOG_ERR, _("Error while processing %s from %s (%s)"),
 161                                    request_name[reqno], c->name, c->hostname);
 162                         return false;
 163                 }
 164         } else {
 165                 logger(LOG_ERR, _("Bogus data received from %s (%s)"),
 166                            c->name, c->hostname);
 167                 return false;
 168         }
 169
 170         return true;
 171 }
 172
 173 static int past_request_compare(const past_request_t *a, const past_request_t *b) {
 174         return strcmp(a->request, b->request);
 175 }
 176
 177 static void free_past_request(past_request_t *r) {
 178         cp();
 179
 180         if(r->request)
 181                 free(r->request);
 182
 183         free(r);
 184 }
 185
 186 static struct event past_request_event;
 187
 188 bool seen_request(char *request) {
 189         past_request_t *new, p = {0};
 190
 191         cp();
 192
 193         p.request = request;
 194
 195         if(splay_search(past_request_tree, &p)) {
 196                 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Already seen request"));
 197                 return true;
 198         } else {
 199                 new = xmalloc(sizeof *new);
 200                 new->request = xstrdup(request);
 201                 new->firstseen = time(NULL);
 202                 splay_insert(past_request_tree, new);
 203                 event_add(&past_request_event, &(struct timeval){10, 0});
 204                 return false;
 205         }
 206 }
 207
 208 void age_past_requests(int fd, short events, void *data) {
 209         splay_node_t *node, *next;
 210         past_request_t *p;
 211         int left = 0, deleted = 0;
 212         time_t now = time(NULL);
 213
 214         cp();
 215
 216         for(node = past_request_tree->head; node; node = next) {
 217                 next = node->next;
 218                 p = node->data;
 219
 220                 if(p->firstseen + pinginterval < now)
 221                         splay_delete_node(past_request_tree, node), deleted++;
 222                 else
 223                         left++;
 224         }
 225
 226         if(left || deleted)
 227                 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Aging past requests: deleted %d, left %d"),
 228                            deleted, left);
 229
 230         if(left)
 231                 event_add(&past_request_event, &(struct timeval){10, 0});
 232 }
 233
 234 void init_requests(void) {
 235         cp();
 236
 237         past_request_tree = splay_alloc_tree((splay_compare_t) past_request_compare, (splay_action_t) free_past_request);
 238
 239         timeout_set(&past_request_event, age_past_requests, NULL);
 240 }
 241
 242 void exit_requests(void) {
 243         cp();
 244
 245         splay_delete_tree(past_request_tree);
 246
 247         event_del(&past_request_event);
 248 }