tinc/src/meta.c

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/*
meta.c -- handle the meta communication
Copyright (C) 2000-2003 Guus Sliepen <guus@sliepen.eu.org>,
2000-2003 Ivo Timmermans <ivo@o2w.nl>
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., 675 Mass Ave, Cambridge, MA 02139, USA.
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$Id: meta.c,v 1.1.2.38 2003/07/29 22:59:00 guus Exp $
*/
#include "system.h"
#include <openssl/evp.h>
#include "avl_tree.h"
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#include "connection.h"
#include "logger.h"
#include "net.h"
#include "protocol.h"
#include "system.h"
#include "utils.h"
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bool send_meta(connection_t *c, char *buffer, int length)
{
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char *bufp;
int outlen;
char outbuf[MAXBUFSIZE];
int result;
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cp();
ifdebug(META) logger(LOG_DEBUG, _("Sending %d bytes of metadata to %s (%s)"), length,
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c->name, c->hostname);
if(c->status.encryptout) {
EVP_EncryptUpdate(c->outctx, outbuf, &outlen, buffer, length);
bufp = outbuf;
length = outlen;
} else
bufp = buffer;
while(length) {
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result = send(c->socket, bufp, length, 0);
if(result <= 0) {
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if(errno == EINTR)
continue;
logger(LOG_ERR, _("Sending meta data to %s (%s) failed: %s"), c->name,
c->hostname, strerror(errno));
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return false;
}
bufp += result;
length -= result;
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}
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return true;
}
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void broadcast_meta(connection_t *from, char *buffer, int length)
{
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avl_node_t *node;
connection_t *c;
cp();
for(node = connection_tree->head; node; node = node->next) {
c = (connection_t *) node->data;
if(c != from && c->status.active)
send_meta(c, buffer, length);
}
}
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bool receive_meta(connection_t *c)
{
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int x;
socklen_t l = sizeof(x);
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int oldlen, i;
int lenin, reqlen;
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bool decrypted = false;
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char inbuf[MAXBUFSIZE];
cp();
if(getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0) {
logger(LOG_ERR, _("This is a bug: %s:%d: %d:%s %s (%s)"), __FILE__,
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__LINE__, c->socket, strerror(errno), c->name, c->hostname);
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return false;
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}
if(x) {
logger(LOG_ERR, _("Metadata socket error for %s (%s): %s"),
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c->name, c->hostname, strerror(x));
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return false;
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}
/* Strategy:
- Read as much as possible from the TCP socket in one go.
- Decrypt it.
- Check if a full request is in the input buffer.
- If yes, process request and remove it from the buffer,
then check again.
- If not, keep stuff in buffer and exit.
*/
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lenin = recv(c->socket, c->buffer + c->buflen, MAXBUFSIZE - c->buflen, 0);
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if(lenin <= 0) {
if(lenin == 0) {
ifdebug(CONNECTIONS) logger(LOG_NOTICE, _("Connection closed by %s (%s)"),
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c->name, c->hostname);
} else if(errno == EINTR)
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return true;
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else
logger(LOG_ERR, _("Metadata socket read error for %s (%s): %s"),
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c->name, c->hostname, strerror(errno));
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return false;
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}
oldlen = c->buflen;
c->buflen += lenin;
while(lenin) {
/* Decrypt */
if(c->status.decryptin && !decrypted) {
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EVP_DecryptUpdate(c->inctx, inbuf, &lenin, c->buffer + oldlen, lenin);
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memcpy(c->buffer + oldlen, inbuf, lenin);
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decrypted = true;
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}
/* Are we receiving a TCPpacket? */
if(c->tcplen) {
if(c->tcplen <= c->buflen) {
receive_tcppacket(c, c->buffer, c->tcplen);
c->buflen -= c->tcplen;
lenin -= c->tcplen;
memmove(c->buffer, c->buffer + c->tcplen, c->buflen);
oldlen = 0;
c->tcplen = 0;
continue;
} else {
break;
}
}
/* Otherwise we are waiting for a request */
reqlen = 0;
for(i = oldlen; i < c->buflen; i++) {
if(c->buffer[i] == '\n') {
c->buffer[i] = '\0'; /* replace end-of-line by end-of-string so we can use sscanf */
reqlen = i + 1;
break;
}
}
if(reqlen) {
c->reqlen = reqlen;
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if(!receive_request(c))
return false;
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c->buflen -= reqlen;
lenin -= reqlen;
memmove(c->buffer, c->buffer + reqlen, c->buflen);
oldlen = 0;
continue;
} else {
break;
}
}
if(c->buflen >= MAXBUFSIZE) {
logger(LOG_ERR, _("Metadata read buffer overflow for %s (%s)"),
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c->name, c->hostname);
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return false;
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}
c->last_ping_time = now;
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return true;
}