BadVPN – Rev 1
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/**
* @file FragmentProtoDisassembler.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stddef.h>
#include <string.h>
#include <misc/debug.h>
#include <misc/byteorder.h>
#include <misc/minmax.h>
#include "client/FragmentProtoDisassembler.h"
static void write_chunks (FragmentProtoDisassembler *o)
{
#define IN_AVAIL (o->in_len - o->in_used)
#define OUT_AVAIL ((o->output_mtu - o->out_used) - (int)sizeof(struct fragmentproto_chunk_header))
ASSERT(o->in_len >= 0)
ASSERT(o->out)
ASSERT(OUT_AVAIL > 0)
// write chunks to output packet
do {
// calculate chunk length
int chunk_len = bmin_int(IN_AVAIL, OUT_AVAIL);
if (o->chunk_mtu > 0) {
chunk_len = bmin_int(chunk_len, o->chunk_mtu);
}
// write chunk header
struct fragmentproto_chunk_header header;
header.frame_id = htol16(o->frame_id);
header.chunk_start = htol16(o->in_used);
header.chunk_len = htol16(chunk_len);
header.is_last = (chunk_len == IN_AVAIL);
memcpy(o->out + o->out_used, &header, sizeof(header));
// write chunk data
memcpy(o->out + o->out_used + sizeof(struct fragmentproto_chunk_header), o->in + o->in_used, chunk_len);
// increment pointers
o->in_used += chunk_len;
o->out_used += sizeof(struct fragmentproto_chunk_header) + chunk_len;
} while (IN_AVAIL > 0 && OUT_AVAIL > 0);
// have we finished the input packet?
if (IN_AVAIL == 0) {
// set no input packet
o->in_len = -1;
// increment frame ID
o->frame_id++;
// finish input
PacketPassInterface_Done(&o->input);
}
// should we finish the output packet?
if (OUT_AVAIL <= 0 || o->latency < 0) {
// set no output packet
o->out = NULL;
// stop timer (if it's running)
if (o->latency >= 0) {
BReactor_RemoveTimer(o->reactor, &o->timer);
}
// finish output
PacketRecvInterface_Done(&o->output, o->out_used);
} else {
// start timer if we have output and it's not running (output was empty before)
if (!BTimer_IsRunning(&o->timer)) {
BReactor_SetTimer(o->reactor, &o->timer);
}
}
}
static void input_handler_send (FragmentProtoDisassembler *o, uint8_t *data, int data_len)
{
ASSERT(data_len >= 0)
ASSERT(o->in_len == -1)
// set input packet
o->in_len = data_len;
o->in = data;
o->in_used = 0;
// if there is no output, wait for it
if (!o->out) {
return;
}
write_chunks(o);
}
static void input_handler_requestcancel (FragmentProtoDisassembler *o)
{
ASSERT(o->in_len >= 0)
ASSERT(!o->out)
// set no input packet
o->in_len = -1;
// finish input
PacketPassInterface_Done(&o->input);
}
static void output_handler_recv (FragmentProtoDisassembler *o, uint8_t *data)
{
ASSERT(data)
ASSERT(!o->out)
// set output packet
o->out = data;
o->out_used = 0;
// if there is no input, wait for it
if (o->in_len < 0) {
return;
}
write_chunks(o);
}
static void timer_handler (FragmentProtoDisassembler *o)
{
ASSERT(o->latency >= 0)
ASSERT(o->out)
ASSERT(o->in_len == -1)
// set no output packet
o->out = NULL;
// finish output
PacketRecvInterface_Done(&o->output, o->out_used);
}
void FragmentProtoDisassembler_Init (FragmentProtoDisassembler *o, BReactor *reactor, int input_mtu, int output_mtu, int chunk_mtu, btime_t latency)
{
ASSERT(input_mtu >= 0)
ASSERT(input_mtu <= UINT16_MAX)
ASSERT(output_mtu > sizeof(struct fragmentproto_chunk_header))
ASSERT(chunk_mtu > 0 || chunk_mtu < 0)
// init arguments
o->reactor = reactor;
o->output_mtu = output_mtu;
o->chunk_mtu = chunk_mtu;
o->latency = latency;
// init input
PacketPassInterface_Init(&o->input, input_mtu, (PacketPassInterface_handler_send)input_handler_send, o, BReactor_PendingGroup(reactor));
PacketPassInterface_EnableCancel(&o->input, (PacketPassInterface_handler_requestcancel)input_handler_requestcancel);
// init output
PacketRecvInterface_Init(&o->output, o->output_mtu, (PacketRecvInterface_handler_recv)output_handler_recv, o, BReactor_PendingGroup(reactor));
// init timer
if (o->latency >= 0) {
BTimer_Init(&o->timer, o->latency, (BTimer_handler)timer_handler, o);
}
// have no input packet
o->in_len = -1;
// have no output packet
o->out = NULL;
// start with zero frame ID
o->frame_id = 0;
DebugObject_Init(&o->d_obj);
}
void FragmentProtoDisassembler_Free (FragmentProtoDisassembler *o)
{
DebugObject_Free(&o->d_obj);
// free timer
if (o->latency >= 0) {
BReactor_RemoveTimer(o->reactor, &o->timer);
}
// free output
PacketRecvInterface_Free(&o->output);
// free input
PacketPassInterface_Free(&o->input);
}
PacketPassInterface * FragmentProtoDisassembler_GetInput (FragmentProtoDisassembler *o)
{
DebugObject_Access(&o->d_obj);
return &o->input;
}
PacketRecvInterface * FragmentProtoDisassembler_GetOutput (FragmentProtoDisassembler *o)
{
DebugObject_Access(&o->d_obj);
return &o->output;
}