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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.
*/
#include "ngtcp2_ppe.h"
#include <string.h>
#include <assert.h>
#include "ngtcp2_str.h"
#include "ngtcp2_conv.h"
void ngtcp2_ppe_init(ngtcp2_ppe *ppe, uint8_t *out, size_t outlen,
ngtcp2_crypto_cc *cc) {
ngtcp2_buf_init(&ppe->buf, out, outlen);
ppe->hdlen = 0;
ppe->len_offset = 0;
ppe->pkt_num_offset = 0;
ppe->pkt_numlen = 0;
ppe->pkt_num = 0;
ppe->sample_offset = 0;
ppe->cc = cc;
}
int ngtcp2_ppe_encode_hd(ngtcp2_ppe *ppe, const ngtcp2_pkt_hd *hd) {
ngtcp2_ssize rv;
ngtcp2_buf *buf = &ppe->buf;
ngtcp2_crypto_cc *cc = ppe->cc;
if (ngtcp2_buf_left(buf) < cc->aead.max_overhead) {
return NGTCP2_ERR_NOBUF;
}
if (hd->flags & NGTCP2_PKT_FLAG_LONG_FORM) {
ppe->len_offset = 1 + 4 + 1 + hd->dcid.datalen + 1 + hd->scid.datalen;
if (hd->type == NGTCP2_PKT_INITIAL) {
ppe->len_offset += ngtcp2_put_uvarintlen(hd->token.len) + hd->token.len;
}
ppe->pkt_num_offset = ppe->len_offset + NGTCP2_PKT_LENGTHLEN;
rv = ngtcp2_pkt_encode_hd_long(
buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, hd);
} else {
ppe->pkt_num_offset = 1 + hd->dcid.datalen;
rv = ngtcp2_pkt_encode_hd_short(
buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, hd);
}
if (rv < 0) {
return (int)rv;
}
ppe->sample_offset = ppe->pkt_num_offset + 4;
buf->last += rv;
ppe->pkt_numlen = hd->pkt_numlen;
ppe->hdlen = (size_t)rv;
ppe->pkt_num = hd->pkt_num;
return 0;
}
int ngtcp2_ppe_encode_frame(ngtcp2_ppe *ppe, ngtcp2_frame *fr) {
ngtcp2_ssize rv;
ngtcp2_buf *buf = &ppe->buf;
ngtcp2_crypto_cc *cc = ppe->cc;
if (ngtcp2_buf_left(buf) < cc->aead.max_overhead) {
return NGTCP2_ERR_NOBUF;
}
rv = ngtcp2_pkt_encode_frame(
buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, fr);
if (rv < 0) {
return (int)rv;
}
buf->last += rv;
return 0;
}
ngtcp2_ssize ngtcp2_ppe_final(ngtcp2_ppe *ppe, const uint8_t **ppkt) {
ngtcp2_buf *buf = &ppe->buf;
ngtcp2_crypto_cc *cc = ppe->cc;
uint8_t *payload = buf->begin + ppe->hdlen;
size_t payloadlen = ngtcp2_buf_len(buf) - ppe->hdlen;
uint8_t mask[NGTCP2_HP_SAMPLELEN];
uint8_t *p;
size_t i;
int rv;
assert(cc->encrypt);
assert(cc->hp_mask);
if (ppe->len_offset) {
ngtcp2_put_uvarint30(
buf->begin + ppe->len_offset,
(uint16_t)(payloadlen + ppe->pkt_numlen + cc->aead.max_overhead));
}
ngtcp2_crypto_create_nonce(ppe->nonce, cc->ckm->iv.base, cc->ckm->iv.len,
ppe->pkt_num);
rv = cc->encrypt(payload, &cc->aead, &cc->ckm->aead_ctx, payload, payloadlen,
ppe->nonce, cc->ckm->iv.len, buf->begin, ppe->hdlen);
if (rv != 0) {
return NGTCP2_ERR_CALLBACK_FAILURE;
}
buf->last = payload + payloadlen + cc->aead.max_overhead;
/* TODO Check that we have enough space to get sample */
assert(ppe->sample_offset + NGTCP2_HP_SAMPLELEN <= ngtcp2_buf_len(buf));
rv = cc->hp_mask(mask, &cc->hp, &cc->hp_ctx, buf->begin + ppe->sample_offset);
if (rv != 0) {
return NGTCP2_ERR_CALLBACK_FAILURE;
}
p = buf->begin;
if (*p & NGTCP2_HEADER_FORM_BIT) {
*p = (uint8_t)(*p ^ (mask[0] & 0x0f));
} else {
*p = (uint8_t)(*p ^ (mask[0] & 0x1f));
}
p = buf->begin + ppe->pkt_num_offset;
for (i = 0; i < ppe->pkt_numlen; ++i) {
*(p + i) ^= mask[i + 1];
}
if (ppkt != NULL) {
*ppkt = buf->begin;
}
return (ngtcp2_ssize)ngtcp2_buf_len(buf);
}
size_t ngtcp2_ppe_left(ngtcp2_ppe *ppe) {
ngtcp2_crypto_cc *cc = ppe->cc;
if (ngtcp2_buf_left(&ppe->buf) < cc->aead.max_overhead) {
return 0;
}
return ngtcp2_buf_left(&ppe->buf) - cc->aead.max_overhead;
}
size_t ngtcp2_ppe_pktlen(ngtcp2_ppe *ppe) {
ngtcp2_crypto_cc *cc = ppe->cc;
return ngtcp2_buf_len(&ppe->buf) + cc->aead.max_overhead;
}
size_t ngtcp2_ppe_padding(ngtcp2_ppe *ppe) {
ngtcp2_crypto_cc *cc = ppe->cc;
ngtcp2_buf *buf = &ppe->buf;
size_t len;
assert(ngtcp2_buf_left(buf) >= cc->aead.max_overhead);
len = ngtcp2_buf_left(buf) - cc->aead.max_overhead;
memset(buf->last, 0, len);
buf->last += len;
return len;
}
size_t ngtcp2_ppe_padding_hp_sample(ngtcp2_ppe *ppe) {
ngtcp2_crypto_cc *cc = ppe->cc;
ngtcp2_buf *buf = &ppe->buf;
size_t max_samplelen;
size_t len = 0;
assert(cc->aead.max_overhead);
max_samplelen =
ngtcp2_buf_len(buf) + cc->aead.max_overhead - ppe->sample_offset;
if (max_samplelen < NGTCP2_HP_SAMPLELEN) {
len = NGTCP2_HP_SAMPLELEN - max_samplelen;
assert(ngtcp2_ppe_left(ppe) >= len);
memset(buf->last, 0, len);
buf->last += len;
}
return len;
}
size_t ngtcp2_ppe_padding_size(ngtcp2_ppe *ppe, size_t n) {
ngtcp2_crypto_cc *cc = ppe->cc;
ngtcp2_buf *buf = &ppe->buf;
size_t pktlen = ngtcp2_buf_len(buf) + cc->aead.max_overhead;
size_t len;
if (pktlen >= n) {
return 0;
}
len = n - pktlen;
buf->last = ngtcp2_setmem(buf->last, 0, len);
return len;
}
int ngtcp2_ppe_ensure_hp_sample(ngtcp2_ppe *ppe) {
ngtcp2_buf *buf = &ppe->buf;
return ngtcp2_buf_left(buf) >= (4 - ppe->pkt_numlen) + NGTCP2_HP_SAMPLELEN;
}
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