BadVPN – Rev 1
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/**
* @file ChunkBuffer2.h
* @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.
*
* @section DESCRIPTION
*
* Circular packet buffer
*/
#ifndef BADVPN_STRUCTURE_CHUNKBUFFER2_H
#define BADVPN_STRUCTURE_CHUNKBUFFER2_H
#include <stdint.h>
#include <stdlib.h>
#include <limits.h>
#include <misc/balign.h>
#include <misc/debug.h>
#ifndef NDEBUG
#define CHUNKBUFFER2_ASSERT_BUFFER(_buf) _ChunkBuffer2_assert_buffer(_buf);
#define CHUNKBUFFER2_ASSERT_IO(_buf) _ChunkBuffer2_assert_io(_buf);
#else
#define CHUNKBUFFER2_ASSERT_BUFFER(_buf)
#define CHUNKBUFFER2_ASSERT_IO(_buf)
#endif
struct ChunkBuffer2_block {
int len;
};
typedef struct {
struct ChunkBuffer2_block *buffer;
int size;
int wrap;
int start;
int used;
int mtu;
uint8_t *input_dest;
int input_avail;
uint8_t *output_dest;
int output_avail;
} ChunkBuffer2;
// calculates a buffer size needed to hold at least 'num' packets long at least 'chunk_len'
static int ChunkBuffer2_calc_blocks (int chunk_len, int num);
// initialize
static void ChunkBuffer2_Init (ChunkBuffer2 *buf, struct ChunkBuffer2_block *buffer, int blocks, int mtu);
// submit a packet written to the buffer
static void ChunkBuffer2_SubmitPacket (ChunkBuffer2 *buf, int len);
// remove the first packet
static void ChunkBuffer2_ConsumePacket (ChunkBuffer2 *buf);
static int _ChunkBuffer2_end (ChunkBuffer2 *buf)
{
if (buf->used >= buf->wrap - buf->start) {
return (buf->used - (buf->wrap - buf->start));
} else {
return (buf->start + buf->used);
}
}
#ifndef NDEBUG
static void _ChunkBuffer2_assert_buffer (ChunkBuffer2 *buf)
{
ASSERT(buf->size > 0)
ASSERT(buf->wrap > 0)
ASSERT(buf->wrap <= buf->size)
ASSERT(buf->start >= 0)
ASSERT(buf->start < buf->wrap)
ASSERT(buf->used >= 0)
ASSERT(buf->used <= buf->wrap)
ASSERT(buf->wrap == buf->size || buf->used >= buf->wrap - buf->start)
ASSERT(buf->mtu >= 0)
}
static void _ChunkBuffer2_assert_io (ChunkBuffer2 *buf)
{
// check input
int end = _ChunkBuffer2_end(buf);
if (buf->size - end - 1 < buf->mtu) {
// it will never be possible to write a MTU long packet here
ASSERT(!buf->input_dest)
ASSERT(buf->input_avail == -1)
} else {
// calculate number of free blocks
int free;
if (buf->used >= buf->wrap - buf->start) {
free = buf->start - end;
} else {
free = buf->size - end;
}
if (free > 0) {
// got space at least for a header. More space will become available as packets are
// read from the buffer, up to MTU.
ASSERT(buf->input_dest == (uint8_t *)&buf->buffer[end + 1])
ASSERT(buf->input_avail == (free - 1) * sizeof(struct ChunkBuffer2_block))
} else {
// no space
ASSERT(!buf->input_dest)
ASSERT(buf->input_avail == -1)
}
}
// check output
if (buf->used > 0) {
int datalen = buf->buffer[buf->start].len;
ASSERT(datalen >= 0)
int blocklen = bdivide_up(datalen, sizeof(struct ChunkBuffer2_block));
ASSERT(blocklen <= buf->used - 1)
ASSERT(blocklen <= buf->wrap - buf->start - 1)
ASSERT(buf->output_dest == (uint8_t *)&buf->buffer[buf->start + 1])
ASSERT(buf->output_avail == datalen)
} else {
ASSERT(!buf->output_dest)
ASSERT(buf->output_avail == -1)
}
}
#endif
static void _ChunkBuffer2_update_input (ChunkBuffer2 *buf)
{
int end = _ChunkBuffer2_end(buf);
if (buf->size - end - 1 < buf->mtu) {
// it will never be possible to write a MTU long packet here
buf->input_dest = NULL;
buf->input_avail = -1;
return;
}
// calculate number of free blocks
int free;
if (buf->used >= buf->wrap - buf->start) {
free = buf->start - end;
} else {
free = buf->size - end;
}
if (free > 0) {
// got space at least for a header. More space will become available as packets are
// read from the buffer, up to MTU.
buf->input_dest = (uint8_t *)&buf->buffer[end + 1];
buf->input_avail = (free - 1) * sizeof(struct ChunkBuffer2_block);
} else {
// no space
buf->input_dest = NULL;
buf->input_avail = -1;
}
}
static void _ChunkBuffer2_update_output (ChunkBuffer2 *buf)
{
if (buf->used > 0) {
int datalen = buf->buffer[buf->start].len;
ASSERT(datalen >= 0)
#ifndef NDEBUG
int blocklen = bdivide_up(datalen, sizeof(struct ChunkBuffer2_block));
ASSERT(blocklen <= buf->used - 1)
ASSERT(blocklen <= buf->wrap - buf->start - 1)
#endif
buf->output_dest = (uint8_t *)&buf->buffer[buf->start + 1];
buf->output_avail = datalen;
} else {
buf->output_dest = NULL;
buf->output_avail = -1;
}
}
int ChunkBuffer2_calc_blocks (int chunk_len, int num)
{
int chunk_data_blocks = bdivide_up(chunk_len, sizeof(struct ChunkBuffer2_block));
if (chunk_data_blocks > INT_MAX - 1) {
return -1;
}
int chunk_blocks = 1 + chunk_data_blocks;
if (num > INT_MAX - 1) {
return -1;
}
int num_chunks = num + 1;
if (chunk_blocks > INT_MAX / num_chunks) {
return -1;
}
int blocks = chunk_blocks * num_chunks;
return blocks;
}
void ChunkBuffer2_Init (ChunkBuffer2 *buf, struct ChunkBuffer2_block *buffer, int blocks, int mtu)
{
ASSERT(blocks > 0)
ASSERT(mtu >= 0)
buf->buffer = buffer;
buf->size = blocks;
buf->wrap = blocks;
buf->start = 0;
buf->used = 0;
buf->mtu = bdivide_up(mtu, sizeof(struct ChunkBuffer2_block));
CHUNKBUFFER2_ASSERT_BUFFER(buf)
_ChunkBuffer2_update_input(buf);
_ChunkBuffer2_update_output(buf);
CHUNKBUFFER2_ASSERT_IO(buf)
}
void ChunkBuffer2_SubmitPacket (ChunkBuffer2 *buf, int len)
{
ASSERT(buf->input_dest)
ASSERT(len >= 0)
ASSERT(len <= buf->input_avail)
CHUNKBUFFER2_ASSERT_BUFFER(buf)
CHUNKBUFFER2_ASSERT_IO(buf)
int end = _ChunkBuffer2_end(buf);
int blocklen = bdivide_up(len, sizeof(struct ChunkBuffer2_block));
ASSERT(blocklen <= buf->size - end - 1)
ASSERT(buf->used < buf->wrap - buf->start || blocklen <= buf->start - end - 1)
buf->buffer[end].len = len;
buf->used += 1 + blocklen;
if (buf->used <= buf->wrap - buf->start && buf->mtu > buf->size - (end + 1 + blocklen) - 1) {
buf->wrap = end + 1 + blocklen;
}
CHUNKBUFFER2_ASSERT_BUFFER(buf)
// update input
_ChunkBuffer2_update_input(buf);
// update output
if (buf->used == 1 + blocklen) {
_ChunkBuffer2_update_output(buf);
}
CHUNKBUFFER2_ASSERT_IO(buf)
}
void ChunkBuffer2_ConsumePacket (ChunkBuffer2 *buf)
{
ASSERT(buf->output_dest)
CHUNKBUFFER2_ASSERT_BUFFER(buf)
CHUNKBUFFER2_ASSERT_IO(buf)
ASSERT(1 <= buf->wrap - buf->start)
ASSERT(1 <= buf->used)
int blocklen = bdivide_up(buf->buffer[buf->start].len, sizeof(struct ChunkBuffer2_block));
ASSERT(blocklen <= buf->wrap - buf->start - 1)
ASSERT(blocklen <= buf->used - 1)
int data_wrapped = (buf->used >= buf->wrap - buf->start);
buf->start += 1 + blocklen;
buf->used -= 1 + blocklen;
if (buf->start == buf->wrap) {
buf->start = 0;
buf->wrap = buf->size;
}
CHUNKBUFFER2_ASSERT_BUFFER(buf)
// update input
if (data_wrapped) {
_ChunkBuffer2_update_input(buf);
}
// update output
_ChunkBuffer2_update_output(buf);
CHUNKBUFFER2_ASSERT_IO(buf)
}
#endif