2 meta.c -- handle the meta communication
3 Copyright (C) 2000-2017 Guus Sliepen <guus@tinc-vpn.org>,
4 2000-2005 Ivo Timmermans
5 2006 Scott Lamb <slamb@slamb.org>
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License along
18 with this program; if not, write to the Free Software Foundation, Inc.,
19 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
24 #include <openssl/err.h>
25 #include <openssl/evp.h>
28 #include "connection.h"
37 bool send_meta(connection_t *c, const char *buffer, int length) {
41 ifdebug(META) logger(LOG_DEBUG, "Sending %d bytes of metadata to %s (%s)", length,
42 c->name, c->hostname);
45 c->last_flushed_time = now;
48 /* Find room in connection's buffer */
49 if(length + c->outbuflen > c->outbufsize) {
50 c->outbufsize = length + c->outbuflen;
51 c->outbuf = xrealloc(c->outbuf, c->outbufsize);
54 if(length + c->outbuflen + c->outbufstart > c->outbufsize) {
55 memmove(c->outbuf, c->outbuf + c->outbufstart, c->outbuflen);
59 /* Add our data to buffer */
60 if(c->status.encryptout) {
61 /* Check encryption limits */
62 if((uint64_t)length > c->outbudget) {
63 ifdebug(META) logger(LOG_ERR, "Byte limit exceeded for encryption to %s (%s)", c->name, c->hostname);
66 c->outbudget -= length;
69 result = EVP_EncryptUpdate(c->outctx, (unsigned char *)c->outbuf + c->outbufstart + c->outbuflen,
70 &outlen, (unsigned char *)buffer, length);
72 if(!result || outlen < length) {
73 logger(LOG_ERR, "Error while encrypting metadata to %s (%s): %s",
74 c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
76 } else if(outlen > length) {
77 logger(LOG_EMERG, "Encrypted data too long! Heap corrupted!");
81 c->outbuflen += outlen;
83 memcpy(c->outbuf + c->outbufstart + c->outbuflen, buffer, length);
84 c->outbuflen += length;
90 bool flush_meta(connection_t *c) {
93 ifdebug(META) logger(LOG_DEBUG, "Flushing %d bytes to %s (%s)",
94 c->outbuflen, c->name, c->hostname);
97 result = send(c->socket, c->outbuf + c->outbufstart, c->outbuflen, 0);
100 if(!errno || errno == EPIPE) {
101 ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection closed by %s (%s)",
102 c->name, c->hostname);
103 } else if(errno == EINTR) {
105 } else if(sockwouldblock(sockerrno)) {
106 ifdebug(META) logger(LOG_DEBUG, "Flushing %d bytes to %s (%s) would block",
107 c->outbuflen, c->name, c->hostname);
110 logger(LOG_ERR, "Flushing meta data to %s (%s) failed: %s", c->name,
111 c->hostname, sockstrerror(sockerrno));
117 c->outbufstart += result;
118 c->outbuflen -= result;
121 c->outbufstart = 0; /* avoid unnecessary memmoves */
125 void broadcast_meta(connection_t *from, const char *buffer, int length) {
129 for(node = connection_tree->head; node; node = node->next) {
132 if(c != from && c->status.active) {
133 send_meta(c, buffer, length);
138 bool receive_meta(connection_t *c) {
139 int oldlen, i, result;
140 int lenin, lenout, reqlen;
141 bool decrypted = false;
142 char inbuf[MAXBUFSIZE];
145 - Read as much as possible from the TCP socket in one go.
147 - Check if a full request is in the input buffer.
148 - If yes, process request and remove it from the buffer,
150 - If not, keep stuff in buffer and exit.
153 lenin = recv(c->socket, c->buffer + c->buflen, MAXBUFSIZE - c->buflen, 0);
156 if(!lenin || !errno) {
157 ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection closed by %s (%s)",
158 c->name, c->hostname);
159 } else if(sockwouldblock(sockerrno)) {
162 logger(LOG_ERR, "Metadata socket read error for %s (%s): %s",
163 c->name, c->hostname, sockstrerror(sockerrno));
174 /* Is it proxy metadata? */
176 if(c->allow_request == PROXY) {
177 reqlen = receive_proxy_meta(c);
188 if(c->status.decryptin && !decrypted) {
189 /* Check decryption limits */
190 if((uint64_t)lenin > c->inbudget) {
191 ifdebug(META) logger(LOG_ERR, "Byte limit exceeded for decryption from %s (%s)", c->name, c->hostname);
194 c->inbudget -= lenin;
197 result = EVP_DecryptUpdate(c->inctx, (unsigned char *)inbuf, &lenout, (unsigned char *)c->buffer + oldlen, lenin);
199 if(!result || lenout != lenin) {
200 logger(LOG_ERR, "Error while decrypting metadata from %s (%s): %s",
201 c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
205 memcpy(c->buffer + oldlen, inbuf, lenin);
209 /* Are we receiving a TCPpacket? */
212 if(c->tcplen <= c->buflen) {
213 if(c->allow_request != ALL) {
214 logger(LOG_ERR, "Got unauthorized TCP packet from %s (%s)", c->name, c->hostname);
218 receive_tcppacket(c, c->buffer, c->tcplen);
223 /* Otherwise we are waiting for a request */
225 for(i = oldlen; i < c->buflen; i++) {
226 if(c->buffer[i] == '\n') {
227 c->buffer[i] = '\0'; /* replace end-of-line by end-of-string so we can use sscanf */
228 c->reqlen = reqlen = i + 1;
233 if(reqlen && !receive_request(c)) {
242 lenin -= reqlen - oldlen;
243 memmove(c->buffer, c->buffer + reqlen, c->buflen);
251 if(c->buflen >= MAXBUFSIZE) {
252 logger(LOG_ERR, "Metadata read buffer overflow for %s (%s)",
253 c->name, c->hostname);