michael@0: /*
michael@0: Copyright (c) 2007, Adobe Systems, Incorporated
michael@0: All rights reserved.
michael@0: 
michael@0: Redistribution and use in source and binary forms, with or without
michael@0: modification, are permitted provided that the following conditions are
michael@0: met:
michael@0: 
michael@0: * Redistributions of source code must retain the above copyright
michael@0:   notice, this list of conditions and the following disclaimer.
michael@0: 
michael@0: * Redistributions in binary form must reproduce the above copyright
michael@0:   notice, this list of conditions and the following disclaimer in the
michael@0:   documentation and/or other materials provided with the distribution.
michael@0: 
michael@0: * Neither the name of Adobe Systems, Network Resonance nor the names of its
michael@0:   contributors may be used to endorse or promote products derived from
michael@0:   this software without specific prior written permission.
michael@0: 
michael@0: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0: "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0: LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0: A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
michael@0: OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@0: SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@0: LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0: DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0: THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0: (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0: OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0: */
michael@0: 
michael@0: 
michael@0: static char *RCSSTRING __UNUSED__="$Id: stun_hint.c,v 1.2 2008/04/28 18:21:30 ekr Exp $";
michael@0: 
michael@0: 
michael@0: #include <errno.h>
michael@0: #include <csi_platform.h>
michael@0: 
michael@0: #ifdef WIN32
michael@0: #include <winsock2.h>
michael@0: #include <stdlib.h>
michael@0: #include <io.h>
michael@0: #include <time.h>
michael@0: #else   /* UNIX */
michael@0: #include <string.h>
michael@0: #endif  /* end UNIX */
michael@0: #include <assert.h>
michael@0: 
michael@0: #include "stun.h"
michael@0: 
michael@0: 
michael@0: /* returns 0 if it's not a STUN message
michael@0:  *         1 if it's likely to be a STUN message
michael@0:  *         2 if it's super likely to be a STUN message
michael@0:  *         3 if it really is a STUN message */
michael@0: int
michael@0: nr_is_stun_message(UCHAR *buf, int len)
michael@0: {
michael@0:    const UINT4 cookie = htonl(NR_STUN_MAGIC_COOKIE);
michael@0:    const UINT4 cookie2 = htonl(NR_STUN_MAGIC_COOKIE2);
michael@0: #if 0
michael@0:    nr_stun_message msg;
michael@0: #endif
michael@0:    UINT2 type;
michael@0:    nr_stun_encoded_attribute* attr;
michael@0:    unsigned int attrLen;
michael@0:    int atrType;
michael@0: 
michael@0:    if (sizeof(nr_stun_message_header) > len)
michael@0:        return 0;
michael@0: 
michael@0:    if ((buf[0] & (0x80|0x40)) != 0)
michael@0:        return 0;
michael@0: 
michael@0:    memcpy(&type, buf, 2);
michael@0:    type = ntohs(type);
michael@0: 
michael@0:    switch (type) {
michael@0:    case NR_STUN_MSG_BINDING_REQUEST:
michael@0:    case NR_STUN_MSG_BINDING_INDICATION:
michael@0:    case NR_STUN_MSG_BINDING_RESPONSE:
michael@0:    case NR_STUN_MSG_BINDING_ERROR_RESPONSE:
michael@0: 
michael@0: #ifdef USE_TURN
michael@0:     case NR_STUN_MSG_ALLOCATE_REQUEST:
michael@0:     case NR_STUN_MSG_ALLOCATE_RESPONSE:
michael@0:     case NR_STUN_MSG_ALLOCATE_ERROR_RESPONSE:
michael@0:     case NR_STUN_MSG_REFRESH_REQUEST:
michael@0:     case NR_STUN_MSG_REFRESH_RESPONSE:
michael@0:     case NR_STUN_MSG_REFRESH_ERROR_RESPONSE:
michael@0:     case NR_STUN_MSG_PERMISSION_REQUEST:
michael@0:     case NR_STUN_MSG_PERMISSION_RESPONSE:
michael@0:     case NR_STUN_MSG_PERMISSION_ERROR_RESPONSE:
michael@0:     case NR_STUN_MSG_CHANNEL_BIND_REQUEST:
michael@0:     case NR_STUN_MSG_CHANNEL_BIND_RESPONSE:
michael@0:     case NR_STUN_MSG_CHANNEL_BIND_ERROR_RESPONSE:
michael@0:     case NR_STUN_MSG_SEND_INDICATION:
michael@0:     case NR_STUN_MSG_DATA_INDICATION:
michael@0: #ifdef NR_STUN_MSG_CONNECT_REQUEST
michael@0:     case NR_STUN_MSG_CONNECT_REQUEST:
michael@0: #endif
michael@0: #ifdef NR_STUN_MSG_CONNECT_RESPONSE
michael@0:     case NR_STUN_MSG_CONNECT_RESPONSE:
michael@0: #endif
michael@0: #ifdef NR_STUN_MSG_CONNECT_ERROR_RESPONSE
michael@0:     case NR_STUN_MSG_CONNECT_ERROR_RESPONSE:
michael@0: #endif
michael@0: #ifdef NR_STUN_MSG_CONNECT_STATUS_INDICATION
michael@0:     case NR_STUN_MSG_CONNECT_STATUS_INDICATION:
michael@0: #endif
michael@0: #endif /* USE_TURN */
michael@0: 
michael@0:         /* ok so far, continue */
michael@0:         break;
michael@0:    default:
michael@0:         return 0;
michael@0:         break;
michael@0:    }
michael@0: 
michael@0:    if (!memcmp(&cookie2, &buf[4], sizeof(UINT4))) {
michael@0:        /* return here because if it's an old-style message then there will
michael@0:         * not be a fingerprint in the message */
michael@0:        return 1;
michael@0:    }
michael@0: 
michael@0:    if (memcmp(&cookie, &buf[4], sizeof(UINT4)))
michael@0:        return 0;
michael@0: 
michael@0:    /* the magic cookie was right, so it's pretty darn likely that what we've
michael@0:     * got here is a STUN message */
michael@0: 
michael@0:    attr = (nr_stun_encoded_attribute*)(buf + (len - 8));
michael@0:    attrLen = ntohs(attr->length);
michael@0:    atrType = ntohs(attr->type);
michael@0: 
michael@0:    if (atrType != NR_STUN_ATTR_FINGERPRINT || attrLen != 4)
michael@0:        return 1;
michael@0: 
michael@0:    /* the fingerprint is in the right place and looks sane, so we can be quite
michael@0:     * sure we've got a STUN message */
michael@0: 
michael@0: #if 0
michael@0: /* nevermind this check ... there's a reasonable chance that a NAT has modified
michael@0:  * the message (and thus the fingerprint check will fail), but it's still an
michael@0:  * otherwise-perfectly-good STUN message, so skip the check since we're going
michael@0:  * to return "true" whether the check succeeds or fails */
michael@0: 
michael@0:    if (nr_stun_parse_attr_UINT4(buf + (len - 4), attrLen, &msg.fingerprint))
michael@0:        return 2;
michael@0: 
michael@0: 
michael@0:    if (nr_stun_compute_fingerprint(buf, len - 8, &computedFingerprint))
michael@0:        return 2;
michael@0: 
michael@0:    if (msg.fingerprint.number != computedFingerprint)
michael@0:        return 2;
michael@0: 
michael@0:    /* and the fingerprint is good, so it's gotta be a STUN message */
michael@0: #endif
michael@0: 
michael@0:    return 3;
michael@0: }
michael@0: 
michael@0: int
michael@0: nr_is_stun_request_message(UCHAR *buf, int len)
michael@0: {
michael@0:    UINT2 type;
michael@0: 
michael@0:    if (sizeof(nr_stun_message_header) > len)
michael@0:        return 0;
michael@0: 
michael@0:    if (!nr_is_stun_message(buf, len))
michael@0:        return 0;
michael@0: 
michael@0:    memcpy(&type, buf, 2);
michael@0:    type = ntohs(type);
michael@0: 
michael@0:    return NR_STUN_GET_TYPE_CLASS(type) == NR_CLASS_REQUEST;
michael@0: }
michael@0: 
michael@0: int
michael@0: nr_is_stun_indication_message(UCHAR *buf, int len)
michael@0: {
michael@0:    UINT2 type;
michael@0: 
michael@0:    if (sizeof(nr_stun_message_header) > len)
michael@0:        return 0;
michael@0: 
michael@0:    if (!nr_is_stun_message(buf, len))
michael@0:        return 0;
michael@0: 
michael@0:    memcpy(&type, buf, 2);
michael@0:    type = ntohs(type);
michael@0: 
michael@0:    return NR_STUN_GET_TYPE_CLASS(type) == NR_CLASS_INDICATION;
michael@0: }
michael@0: 
michael@0: int
michael@0: nr_is_stun_response_message(UCHAR *buf, int len)
michael@0: {
michael@0:    UINT2 type;
michael@0: 
michael@0:    if (sizeof(nr_stun_message_header) > len)
michael@0:        return 0;
michael@0: 
michael@0:    if (!nr_is_stun_message(buf, len))
michael@0:        return 0;
michael@0: 
michael@0:    memcpy(&type, buf, 2);
michael@0:    type = ntohs(type);
michael@0: 
michael@0:    return NR_STUN_GET_TYPE_CLASS(type) == NR_CLASS_RESPONSE
michael@0:        || NR_STUN_GET_TYPE_CLASS(type) == NR_CLASS_ERROR_RESPONSE;
michael@0: }
michael@0: 
michael@0: int
michael@0: nr_has_stun_cookie(UCHAR *buf, int len)
michael@0: {
michael@0:    static UINT4 cookie;
michael@0: 
michael@0:    cookie = htonl(NR_STUN_MAGIC_COOKIE);
michael@0: 
michael@0:    if (sizeof(nr_stun_message_header) > len)
michael@0:        return 0;
michael@0: 
michael@0:    if (memcmp(&cookie, &buf[4], sizeof(UINT4)))
michael@0:        return 0;
michael@0: 
michael@0:    return 1;
michael@0: }
michael@0: 
michael@0: int
michael@0: nr_stun_message_length(UCHAR *buf, int buf_len, int *msg_len)
michael@0: {
michael@0:   nr_stun_message_header *hdr;
michael@0: 
michael@0:   if (!nr_is_stun_message(buf, buf_len))
michael@0:     return(R_BAD_DATA);
michael@0: 
michael@0:   hdr = (nr_stun_message_header *)buf;
michael@0: 
michael@0:   *msg_len = ntohs(hdr->length);
michael@0: 
michael@0:   return(0);
michael@0: }
michael@0: 
michael@0: 
michael@0: