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/*
* ngtcp2
*
* Copyright (c) 2017 ngtcp2 contributors
*
* 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.
*/
#ifndef NGTCP2_PPE_H
#define NGTCP2_PPE_H
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* defined(HAVE_CONFIG_H) */
#include <ngtcp2/ngtcp2.h>
#include "ngtcp2_pkt.h"
#include "ngtcp2_buf.h"
#include "ngtcp2_crypto.h"
/*
* ngtcp2_ppe is the QUIC Packet Encoder.
*/
typedef struct ngtcp2_ppe {
/* buf is the buffer where a QUIC packet is written. */
ngtcp2_buf buf;
/* cc is the encryption context that includes callback functions to
encrypt a QUIC packet, and AEAD cipher, etc. */
ngtcp2_crypto_cc *cc;
/* dgram_offset is the offset in UDP datagram payload that this QUIC
packet is positioned at. */
size_t dgram_offset;
/* hdlen is the number of bytes for packet header written in buf. */
size_t hdlen;
/* len_offset is the offset to Length field. */
size_t len_offset;
/* pkt_num_offset is the offset to packet number field. */
size_t pkt_num_offset;
/* pkt_numlen is the number of bytes used to encode a packet
number */
size_t pkt_numlen;
/* pkt_num is the packet number written in buf. */
int64_t pkt_num;
/* nonce is the buffer to store nonce. It should be equal or longer
than the length of IV. */
uint8_t nonce[32];
} ngtcp2_ppe;
/*
* ngtcp2_ppe_init initializes |ppe| with the given buffer.
*/
void ngtcp2_ppe_init(ngtcp2_ppe *ppe, uint8_t *out, size_t outlen,
size_t dgram_offset, ngtcp2_crypto_cc *cc);
/*
* ngtcp2_ppe_encode_hd encodes |hd|.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGTCP2_ERR_NOBUF
* The buffer is too small.
*/
int ngtcp2_ppe_encode_hd(ngtcp2_ppe *ppe, const ngtcp2_pkt_hd *hd);
/*
* ngtcp2_ppe_encode_frame encodes |fr|.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGTCP2_ERR_NOBUF
* The buffer is too small.
*/
int ngtcp2_ppe_encode_frame(ngtcp2_ppe *ppe, ngtcp2_frame *fr);
/*
* ngtcp2_ppe_final encrypts QUIC packet payload. If |ppkt| is not
* NULL, the pointer to the packet is assigned to it.
*
* This function returns the length of QUIC packet, including header,
* and payload if it succeeds, or one of the following negative error
* codes:
*
* NGTCP2_ERR_CALLBACK_FAILURE
* User-defined callback function failed.
*/
ngtcp2_ssize ngtcp2_ppe_final(ngtcp2_ppe *ppe, const uint8_t **ppkt);
/*
* ngtcp2_ppe_left returns the number of bytes left to write
* additional frames. This does not count AEAD overhead.
*/
size_t ngtcp2_ppe_left(const ngtcp2_ppe *ppe);
/*
* ngtcp2_ppe_dgram_padding is equivalent to call
* ngtcp2_ppe_dgram_padding_size(ppe, NGTCP2_MAX_UDP_PAYLOAD_SIZE).
* This function should be called just before calling
* ngtcp2_ppe_final().
*
* This function returns the number of bytes padded.
*/
size_t ngtcp2_ppe_dgram_padding(ngtcp2_ppe *ppe);
/*
* ngtcp2_ppe_dgram_padding_size adds PADDING frame so that the size
* of a UDP datagram payload is at least |n| bytes long. If it is
* unable to add PADDING in that way, this function still adds PADDING
* frame as much as possible. This function should be called just
* before calling ngtcp2_ppe_final().
*
* This function returns the number of bytes added as padding.
*/
size_t ngtcp2_ppe_dgram_padding_size(ngtcp2_ppe *ppe, size_t n);
/*
* ngtcp2_ppe_padding_size adds PADDING frame so that the size of QUIC
* packet is at least |n| bytes long and the current payload has
* enough space for header protection sample. If it is unable to add
* PADDING at least |n| bytes, this function still adds PADDING frames
* as much as possible. This function also adds PADDING frames so
* that the minimum padding requirement of header protection is met.
* Those padding may be larger than |n| bytes. It is recommended to
* make sure that ngtcp2_ppe_ensure_hp_sample succeeds after writing
* QUIC packet header. This function should be called just before
* calling ngtcp2_ppe_final().
*
* This function returns the number of bytes added as padding.
*/
size_t ngtcp2_ppe_padding_size(ngtcp2_ppe *ppe, size_t n);
/*
* ngtcp2_ppe_ensure_hp_sample returns nonzero if the buffer has
* enough space for header protection sample. This should be called
* right after packet header is written.
*/
int ngtcp2_ppe_ensure_hp_sample(ngtcp2_ppe *ppe);
#endif /* !defined(NGTCP2_PPE_H) */
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