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ikev1: Add fragmentation support for Windows peers

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I still think ipsec/l2tp with fragmentation support is a useful
fallback option in case the Windows IKEv2 connection fails because
of fragmentation problems.

Tested with Windows XP, 7 and 8.1.
This commit is contained in:
Volker Rümelin 2014-09-25 09:18:17 +02:00 committed by Tobias Brunner
parent 3633b80147
commit 05db0f97e3
3 changed files with 58 additions and 13 deletions
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30
src/libcharon/sa/ike_sa.c
View File

@ -16,6 +16,28 @@
* for more details.
*/
/*
* Copyright (c) 2014 Volker Rümelin
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <string.h>
#include <sys/stat.h>
#include <errno.h>
@ -1024,6 +1046,14 @@ METHOD(ike_sa_t, generate_message_fragmented, status_t,
break;
case FRAGMENTATION_YES:
use_frags = supports_extension(this, EXT_IKE_FRAGMENTATION);
if (use_frags && this->version == IKEV1 &&
supports_extension(this, EXT_MS_WINDOWS))
{
/* It seems Windows 7 and 8 peers only accept proprietary
* fragmented messages if they expect certificates. */
use_frags = message->get_payload(message,
PLV1_CERTIFICATE) != NULL;
}
break;
default:
break;

2
src/libcharon/sa/ike_sa.h
View File

@ -102,7 +102,7 @@ enum ike_extension_t {
EXT_EAP_ONLY_AUTHENTICATION = (1<<5),
/**
* peer is probably a Windows 7 RAS client
* peer is probably a Windows RAS client
*/
EXT_MS_WINDOWS = (1<<6),

39
src/libcharon/sa/ikev1/tasks/isakmp_vendor.c
View File

@ -15,7 +15,7 @@
*/
/*
* Copyright (C) 2012 Volker Rümelin
* Copyright (C) 2012-2014 Volker Rümelin
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@ -106,10 +106,15 @@ static struct {
"\x12\xf5\xf2\x8c\x45\x71\x68\xa9\x70\x2d\x9f\xe2\x74\xcc\x01\x00"},
/* Proprietary IKE fragmentation extension. Capabilities are handled
* specially on receipt of this VID. */
* specially on receipt of this VID. Windows peers send this VID
* without capabilities, but accept it with and without capabilities. */
{ "FRAGMENTATION", EXT_IKE_FRAGMENTATION, FALSE, 20,
"\x40\x48\xb7\xd5\x6e\xbc\xe8\x85\x25\xe7\xde\x7f\x00\xd6\xc2\xd3\x80\x00\x00\x00"},
/* Windows peers send this VID and a version number */
{ "MS NT5 ISAKMPOAKLEY", EXT_MS_WINDOWS, FALSE, 20,
"\x1e\x2b\x51\x69\x05\x99\x1c\x7d\x7c\x96\xfc\xbf\xb5\x87\xe4\x61\x00\x00\x00\x00"},
}, vendor_natt_ids[] = {
/* NAT-Traversal VIDs ordered by preference */
@ -167,15 +172,27 @@ static struct {
*/
static const u_int32_t fragmentation_ike = 0x80000000;
/**
* Check if the given vendor ID indicate support for fragmentation
*/
static bool fragmentation_supported(chunk_t data, int i)
static bool is_known_vid(chunk_t data, int i)
{
if (vendor_ids[i].extension == EXT_IKE_FRAGMENTATION &&
data.len == 20 && memeq(data.ptr, vendor_ids[i].id, 16))
switch (vendor_ids[i].extension)
{
return untoh32(&data.ptr[16]) & fragmentation_ike;
case EXT_IKE_FRAGMENTATION:
if (data.len >= 16 && memeq(data.ptr, vendor_ids[i].id, 16))
{
switch (data.len)
{
case 16:
return TRUE;
case 20:
return untoh32(&data.ptr[16]) & fragmentation_ike;
}
}
break;
case EXT_MS_WINDOWS:
return data.len == 20 && memeq(data.ptr, vendor_ids[i].id, 16);
default:
return chunk_equals(data, chunk_create(vendor_ids[i].id,
vendor_ids[i].len));
}
return FALSE;
}
@ -251,9 +268,7 @@ static void process(private_isakmp_vendor_t *this, message_t *message)
for (i = 0; i < countof(vendor_ids); i++)
{
if (chunk_equals(data, chunk_create(vendor_ids[i].id,
vendor_ids[i].len)) ||
fragmentation_supported(data, i))
if (is_known_vid(data, i))
{
DBG1(DBG_IKE, "received %s vendor ID", vendor_ids[i].desc);
if (vendor_ids[i].extension)