/* protocol.c -- handle the meta-protocol, basic functions Copyright (C) 1999-2005 Ivo Timmermans, 2000-2009 Guus Sliepen This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "system.h" #include "conf.h" #include "connection.h" #include "logger.h" #include "meta.h" #include "protocol.h" #include "utils.h" #include "xalloc.h" bool tunnelserver = false; bool strictsubnets = false; bool experimental = false; /* Jumptable for the request handlers */ static bool (*request_handlers[])(connection_t *, char *) = { id_h, metakey_h, challenge_h, chal_reply_h, ack_h, status_h, error_h, termreq_h, ping_h, pong_h, add_subnet_h, del_subnet_h, add_edge_h, del_edge_h, key_changed_h, req_key_h, ans_key_h, tcppacket_h, control_h, }; /* Request names */ static char (*request_name[]) = { "ID", "METAKEY", "CHALLENGE", "CHAL_REPLY", "ACK", "STATUS", "ERROR", "TERMREQ", "PING", "PONG", "ADD_SUBNET", "DEL_SUBNET", "ADD_EDGE", "DEL_EDGE", "KEY_CHANGED", "REQ_KEY", "ANS_KEY", "PACKET", "CONTROL", }; static splay_tree_t *past_request_tree; bool check_id(const char *id) { for(; *id; id++) if(!isalnum(*id) && *id != '_') return false; return true; } /* Generic request routines - takes care of logging and error detection as well */ bool send_request(connection_t *c, const char *format, ...) { va_list args; char request[MAXBUFSIZE]; int len; /* Use vsnprintf instead of vxasprintf: faster, no memory fragmentation, cleanup is automatic, and there is a limit on the input buffer anyway */ va_start(args, format); len = vsnprintf(request, MAXBUFSIZE, format, args); va_end(args); if(len < 0 || len > MAXBUFSIZE - 1) { logger(LOG_ERR, "Output buffer overflow while sending request to %s (%s)", c->name, c->hostname); return false; } ifdebug(PROTOCOL) { ifdebug(META) logger(LOG_DEBUG, "Sending %s to %s (%s): %s", request_name[atoi(request)], c->name, c->hostname, request); else logger(LOG_DEBUG, "Sending %s to %s (%s)", request_name[atoi(request)], c->name, c->hostname); } request[len++] = '\n'; if(c == broadcast) { broadcast_meta(NULL, request, len); return true; } else return send_meta(c, request, len); } void forward_request(connection_t *from, char *request) { /* Note: request is not zero terminated anymore after a call to this function! */ ifdebug(PROTOCOL) { ifdebug(META) logger(LOG_DEBUG, "Forwarding %s from %s (%s): %s", request_name[atoi(request)], from->name, from->hostname, request); else logger(LOG_DEBUG, "Forwarding %s from %s (%s)", request_name[atoi(request)], from->name, from->hostname); } int len = strlen(request); request[len++] = '\n'; broadcast_meta(from, request, len); } bool receive_request(connection_t *c, char *request) { int reqno = atoi(request); if(reqno || *request == '0') { if((reqno < 0) || (reqno >= LAST) || !request_handlers[reqno]) { ifdebug(META) logger(LOG_DEBUG, "Unknown request from %s (%s): %s", c->name, c->hostname, request); else logger(LOG_ERR, "Unknown request from %s (%s)", c->name, c->hostname); return false; } else { ifdebug(PROTOCOL) { ifdebug(META) logger(LOG_DEBUG, "Got %s from %s (%s): %s", request_name[reqno], c->name, c->hostname, request); else logger(LOG_DEBUG, "Got %s from %s (%s)", request_name[reqno], c->name, c->hostname); } } if((c->allow_request != ALL) && (c->allow_request != reqno)) { logger(LOG_ERR, "Unauthorized request from %s (%s)", c->name, c->hostname); return false; } if(!request_handlers[reqno](c, request)) { /* Something went wrong. Probably scriptkiddies. Terminate. */ logger(LOG_ERR, "Error while processing %s from %s (%s)", request_name[reqno], c->name, c->hostname); return false; } } else { logger(LOG_ERR, "Bogus data received from %s (%s)", c->name, c->hostname); return false; } return true; } static int past_request_compare(const past_request_t *a, const past_request_t *b) { return strcmp(a->request, b->request); } static void free_past_request(past_request_t *r) { if(r->request) free(r->request); free(r); } static struct event past_request_event; bool seen_request(char *request) { past_request_t *new, p = {NULL}; p.request = request; if(splay_search(past_request_tree, &p)) { ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Already seen request"); return true; } else { new = xmalloc(sizeof *new); new->request = xstrdup(request); new->firstseen = time(NULL); splay_insert(past_request_tree, new); event_add(&past_request_event, &(struct timeval){10, 0}); return false; } } static void age_past_requests(int fd, short events, void *data) { splay_node_t *node, *next; past_request_t *p; int left = 0, deleted = 0; time_t now = time(NULL); for(node = past_request_tree->head; node; node = next) { next = node->next; p = node->data; if(p->firstseen + pinginterval <= now) splay_delete_node(past_request_tree, node), deleted++; else left++; } if(left || deleted) ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Aging past requests: deleted %d, left %d", deleted, left); if(left) event_add(&past_request_event, &(struct timeval){10, 0}); } void init_requests(void) { past_request_tree = splay_alloc_tree((splay_compare_t) past_request_compare, (splay_action_t) free_past_request); timeout_set(&past_request_event, age_past_requests, NULL); } void exit_requests(void) { splay_delete_tree(past_request_tree); if(timeout_initialized(&past_request_event)) event_del(&past_request_event); }