git.meshlink.io Git - meshlink/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 1.28.4.140 2003/07/12 17:41:46 guus Exp $
  21 */
  22
  23 #include "config.h"
  24
  25 #include <sys/types.h>
  26
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <stdio.h>
  30 #include <stdarg.h>
  31 #include <errno.h>
  32
  33 #include <utils.h>
  34 #include <xalloc.h>
  35
  36 #include "conf.h"
  37 #include "protocol.h"
  38 #include "meta.h"
  39 #include "connection.h"
  40 #include "logger.h"
  41
  42 #include "system.h"
  43
  44 /* Jumptable for the request handlers */
  45
  46 static int (*request_handlers[])(connection_t *) = {
  47                 id_h, metakey_h, challenge_h, chal_reply_h, ack_h,
  48                 status_h, error_h, termreq_h,
  49                 ping_h, pong_h,
  50                 add_subnet_h, del_subnet_h,
  51                 add_edge_h, del_edge_h,
  52                 key_changed_h, req_key_h, ans_key_h, tcppacket_h,
  53 };
  54
  55 /* Request names */
  56
  57 static char (*request_name[]) = {
  58                 "ID", "METAKEY", "CHALLENGE", "CHAL_REPLY", "ACK",
  59                 "STATUS", "ERROR", "TERMREQ",
  60                 "PING", "PONG",
  61                 "ADD_SUBNET", "DEL_SUBNET",
  62                 "ADD_EDGE", "DEL_EDGE", "KEY_CHANGED", "REQ_KEY", "ANS_KEY", "PACKET",
  63 };
  64
  65 static avl_tree_t *past_request_tree;
  66
  67 int check_id(char *id)
  68 {
  69         int i;
  70
  71         for(i = 0; i < strlen(id); i++)
  72                 if(!isalnum(id[i]) && id[i] != '_')
  73                         return -1;
  74
  75         return 0;
  76 }
  77
  78 /* Generic request routines - takes care of logging and error
  79    detection as well */
  80
  81 int send_request(connection_t *c, const char *format, ...)
  82 {
  83         va_list args;
  84         char buffer[MAXBUFSIZE];
  85         int len, request;
  86
  87         cp();
  88
  89         /* Use vsnprintf instead of vasprintf: faster, no memory
  90            fragmentation, cleanup is automatic, and there is a limit on the
  91            input buffer anyway */
  92
  93         va_start(args, format);
  94         len = vsnprintf(buffer, MAXBUFSIZE, format, args);
  95         va_end(args);
  96
  97         if(len < 0 || len > MAXBUFSIZE - 1) {
  98                 logger(LOG_ERR, _("Output buffer overflow while sending request to %s (%s)"),
  99                            c->name, c->hostname);
 100                 return -1;
 101         }
 102
 103         ifdebug(PROTOCOL) {
 104                 sscanf(buffer, "%d", &request);
 105                 ifdebug(META)
 106                         logger(LOG_DEBUG, _("Sending %s to %s (%s): %s"),
 107                                    request_name[request], c->name, c->hostname, buffer);
 108                 else
 109                         logger(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request],
 110                                    c->name, c->hostname);
 111         }
 112
 113         buffer[len++] = '\n';
 114
 115         if(c == broadcast)
 116                 return broadcast_meta(NULL, buffer, len);
 117         else
 118                 return send_meta(c, buffer, len);
 119 }
 120
 121 int forward_request(connection_t *from)
 122 {
 123         int request;
 124         cp();
 125
 126         cp();
 127
 128         ifdebug(PROTOCOL) {
 129                 sscanf(from->buffer, "%d", &request);
 130                 ifdebug(META)
 131                         logger(LOG_DEBUG, _("Forwarding %s from %s (%s): %s"),
 132                                    request_name[request], from->name, from->hostname,
 133                                    from->buffer);
 134                 else
 135                         logger(LOG_DEBUG, _("Forwarding %s from %s (%s)"),
 136                                    request_name[request], from->name, from->hostname);
 137         }
 138
 139         from->buffer[from->reqlen - 1] = '\n';
 140
 141         return broadcast_meta(from, from->buffer, from->reqlen);
 142 }
 143
 144 int receive_request(connection_t *c)
 145 {
 146         int request;
 147
 148         cp();
 149
 150         if(sscanf(c->buffer, "%d", &request) == 1) {
 151                 if((request < 0) || (request >= LAST) || !request_handlers[request]) {
 152                         ifdebug(META)
 153                                 logger(LOG_DEBUG, _("Unknown request from %s (%s): %s"),
 154                                            c->name, c->hostname, c->buffer);
 155                         else
 156                                 logger(LOG_ERR, _("Unknown request from %s (%s)"),
 157                                            c->name, c->hostname);
 158
 159                         return -1;
 160                 } else {
 161                         ifdebug(PROTOCOL) {
 162                                 ifdebug(META)
 163                                         logger(LOG_DEBUG, _("Got %s from %s (%s): %s"),
 164                                                    request_name[request], c->name, c->hostname,
 165                                                    c->buffer);
 166                                 else
 167                                         logger(LOG_DEBUG, _("Got %s from %s (%s)"),
 168                                                    request_name[request], c->name, c->hostname);
 169                         }
 170                 }
 171
 172                 if((c->allow_request != ALL) && (c->allow_request != request)) {
 173                         logger(LOG_ERR, _("Unauthorized request from %s (%s)"), c->name,
 174                                    c->hostname);
 175                         return -1;
 176                 }
 177
 178                 if(request_handlers[request] (c))
 179                         /* Something went wrong. Probably scriptkiddies. Terminate. */
 180                 {
 181                         logger(LOG_ERR, _("Error while processing %s from %s (%s)"),
 182                                    request_name[request], c->name, c->hostname);
 183                         return -1;
 184                 }
 185         } else {
 186                 logger(LOG_ERR, _("Bogus data received from %s (%s)"),
 187                            c->name, c->hostname);
 188                 return -1;
 189         }
 190
 191         return 0;
 192 }
 193
 194 static int past_request_compare(past_request_t *a, past_request_t *b)
 195 {
 196         return strcmp(a->request, b->request);
 197 }
 198
 199 static void free_past_request(past_request_t *r)
 200 {
 201         cp();
 202
 203         if(r->request)
 204                 free(r->request);
 205
 206         free(r);
 207 }
 208
 209 void init_requests(void)
 210 {
 211         cp();
 212
 213         past_request_tree = avl_alloc_tree((avl_compare_t) past_request_compare, (avl_action_t) free_past_request);
 214 }
 215
 216 void exit_requests(void)
 217 {
 218         cp();
 219
 220         avl_delete_tree(past_request_tree);
 221 }
 222
 223 int seen_request(char *request)
 224 {
 225         past_request_t p, *new;
 226
 227         cp();
 228
 229         p.request = request;
 230
 231         if(avl_search(past_request_tree, &p)) {
 232                 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Already seen request"));
 233                 return 1;
 234         } else {
 235                 new = (past_request_t *) xmalloc(sizeof(*new));
 236                 new->request = xstrdup(request);
 237                 new->firstseen = now;
 238                 avl_insert(past_request_tree, new);
 239                 return 0;
 240         }
 241 }
 242
 243 void age_past_requests(void)
 244 {
 245         avl_node_t *node, *next;
 246         past_request_t *p;
 247         int left = 0, deleted = 0;
 248
 249         cp();
 250
 251         for(node = past_request_tree->head; node; node = next) {
 252                 next = node->next;
 253                 p = (past_request_t *) node->data;
 254
 255                 if(p->firstseen + pingtimeout < now)
 256                         avl_delete_node(past_request_tree, node), deleted++;
 257                 else
 258                         left++;
 259         }
 260
 261         if(left || deleted)
 262                 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Aging past requests: deleted %d, left %d\n"),
 263                            deleted, left);
 264 }