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/*
protocol.c -- handle the meta-protocol, basic functions
Copyright (C) 1999-2005 Ivo Timmermans,
2000-2016 Guus Sliepen <guus@tinc-vpn.org>
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;
/* Jumptable for the request handlers */
static bool (*request_handlers[])(connection_t *) = {
id_h, metakey_h, challenge_h, chal_reply_h, ack_h,
NULL, NULL, NULL,
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,
};
/* 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",
};
static avl_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 buffer[MAXBUFSIZE];
int len, request = 0;
/* 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(buffer, sizeof(buffer), format, args);
buffer[sizeof(buffer) - 1] = 0;
va_end(args);
if(len < 0 || (size_t)len > sizeof(buffer) - 1) {
logger(LOG_ERR, "Output buffer overflow while sending request to %s (%s)",
c->name, c->hostname);
return false;
}
ifdebug(PROTOCOL) {
sscanf(buffer, "%d", &request);
ifdebug(META)
logger(LOG_DEBUG, "Sending %s to %s (%s): %s",
request_name[request], c->name, c->hostname, buffer);
else
logger(LOG_DEBUG, "Sending %s to %s (%s)", request_name[request],
c->name, c->hostname);
}
buffer[len++] = '\n';
if(c == everyone) {
broadcast_meta(NULL, buffer, len);
return true;
} else {
return send_meta(c, buffer, len);
}
}
void forward_request(connection_t *from) {
int request;
ifdebug(PROTOCOL) {
sscanf(from->buffer, "%d", &request);
ifdebug(META)
logger(LOG_DEBUG, "Forwarding %s from %s (%s): %s",
request_name[request], from->name, from->hostname,
from->buffer);
else
logger(LOG_DEBUG, "Forwarding %s from %s (%s)",
request_name[request], from->name, from->hostname);
}
from->buffer[from->reqlen - 1] = '\n';
broadcast_meta(from, from->buffer, from->reqlen);
}
bool receive_request(connection_t *c) {
int request;
if(sscanf(c->buffer, "%d", &request) == 1) {
if((request < 0) || (request >= LAST) || !request_handlers[request]) {
ifdebug(META)
logger(LOG_DEBUG, "Unknown request from %s (%s): %s",
c->name, c->hostname, c->buffer);
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[request], c->name, c->hostname,
c->buffer);
else
logger(LOG_DEBUG, "Got %s from %s (%s)",
request_name[request], c->name, c->hostname);
}
}
if((c->allow_request != ALL) && (c->allow_request != request)) {
logger(LOG_ERR, "Unauthorized request from %s (%s)", c->name,
c->hostname);
return false;
}
if(!request_handlers[request](c)) {
/* Something went wrong. Probably scriptkiddies. Terminate. */
logger(LOG_ERR, "Error while processing %s from %s (%s)",
request_name[request], 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);
}
void init_requests(void) {
past_request_tree = avl_alloc_tree((avl_compare_t) past_request_compare, (avl_action_t) free_past_request);
}
void exit_requests(void) {
avl_delete_tree(past_request_tree);
}
bool seen_request(char *request) {
past_request_t *new, p = {0};
p.request = request;
if(avl_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 = now;
avl_insert(past_request_tree, new);
return false;
}
}
void age_past_requests(void) {
avl_node_t *node, *next;
past_request_t *p;
int left = 0, deleted = 0;
for(node = past_request_tree->head; node; node = next) {
next = node->next;
p = node->data;
if(p->firstseen + pinginterval <= now) {
avl_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);
}
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