tinc/src/meta.c

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/*
meta.c -- handle the meta communication
Copyright (C) 2000-2009 Guus Sliepen <guus@tinc-vpn.org>,
2000-2005 Ivo Timmermans
2006 Scott Lamb <slamb@slamb.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"
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#include "splay_tree.h"
#include "cipher.h"
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#include "connection.h"
#include "logger.h"
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#include "meta.h"
#include "net.h"
#include "protocol.h"
#include "utils.h"
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#include "xalloc.h"
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bool send_meta(connection_t *c, const char *buffer, int length) {
if(!c) {
logger(LOG_ERR, "send_meta() called with NULL pointer!");
abort();
}
ifdebug(META) logger(LOG_DEBUG, "Sending %d bytes of metadata to %s (%s)", length,
c->name, c->hostname);
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/* Add our data to buffer */
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if(c->status.encryptout) {
char outbuf[length];
size_t outlen = length;
if(!cipher_encrypt(&c->outcipher, outbuf, length, buffer_prepare(&c->outbuf, length), &outlen, false) || outlen != length) {
logger(LOG_ERR, "Error while encrypting metadata to %s (%s)",
c->name, c->hostname);
return false;
}
} else {
buffer_add(&c->outbuf, buffer, length);
}
event_add(&c->outevent, NULL);
return true;
}
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void broadcast_meta(connection_t *from, const char *buffer, int length) {
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splay_node_t *node;
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connection_t *c;
for(node = connection_tree->head; node; node = node->next) {
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c = node->data;
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if(c != from && c->status.active)
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send_meta(c, buffer, length);
}
}
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bool receive_meta(connection_t *c) {
int inlen, reqlen;
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char inbuf[MAXBUFSIZE];
char *bufp = inbuf, *endp;
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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.
*/
inlen = recv(c->socket, inbuf, sizeof inbuf - c->inbuf.len, 0);
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if(inlen <= 0) {
if(!inlen || !errno) {
ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection closed by %s (%s)",
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c->name, c->hostname);
} else if(sockwouldblock(sockerrno))
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return true;
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else
logger(LOG_ERR, "Metadata socket read error for %s (%s): %s",
c->name, c->hostname, sockstrerror(sockerrno));
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return false;
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}
do {
if(!c->status.decryptin) {
endp = memchr(bufp, '\n', inlen);
if(endp)
endp++;
else
endp = bufp + inlen;
buffer_add(&c->inbuf, bufp, endp - bufp);
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inlen -= endp - bufp;
bufp = endp;
} else {
size_t outlen = inlen;
ifdebug(META) logger(LOG_DEBUG, "Received encrypted %d bytes", inlen);
if(!cipher_decrypt(&c->incipher, bufp, inlen, buffer_prepare(&c->inbuf, inlen), &outlen, false) || inlen != outlen) {
logger(LOG_ERR, "Error while decrypting metadata from %s (%s)",
c->name, c->hostname);
return false;
}
inlen = 0;
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}
while(c->inbuf.len) {
/* Are we receiving a TCPpacket? */
if(c->tcplen) {
char *tcpbuffer = buffer_read(&c->inbuf, c->tcplen);
if(tcpbuffer) {
receive_tcppacket(c, tcpbuffer, c->tcplen);
continue;
} else {
break;
}
}
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/* Otherwise we are waiting for a request */
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char *request = buffer_readline(&c->inbuf);
if(request) {
bool result = receive_request(c, request);
if(!result)
return false;
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continue;
} else {
break;
}
}
} while(inlen);
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return true;
}