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/*
* Copyright 2016 iot.bzh
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* This work is a far adaptation of apache-websocket:
* origin: https://github.com/disconnect/apache-websocket
* commit: cfaef071223f11ba016bff7e1e4b7c9e5df45b50
* Copyright 2010-2012 self.disconnect (APACHE-2)
*/
#include <stdlib.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <sys/uio.h>
#include "websock.h"
#define BLOCK_DATA_SIZE 4096
#define FRAME_GET_FIN(BYTE) (((BYTE) >> 7) & 0x01)
#define FRAME_GET_RSV1(BYTE) (((BYTE) >> 6) & 0x01)
#define FRAME_GET_RSV2(BYTE) (((BYTE) >> 5) & 0x01)
#define FRAME_GET_RSV3(BYTE) (((BYTE) >> 4) & 0x01)
#define FRAME_GET_OPCODE(BYTE) ( (BYTE) & 0x0F)
#define FRAME_GET_MASK(BYTE) (((BYTE) >> 7) & 0x01)
#define FRAME_GET_PAYLOAD_LEN(BYTE) ( (BYTE) & 0x7F)
#define FRAME_SET_FIN(BYTE) (((BYTE) & 0x01) << 7)
#define FRAME_SET_OPCODE(BYTE) ((BYTE) & 0x0F)
#define FRAME_SET_MASK(BYTE) (((BYTE) & 0x01) << 7)
#define FRAME_SET_LENGTH(X64, IDX) (unsigned char)(((X64) >> ((IDX)*8)) & 0xFF)
#define OPCODE_CONTINUATION 0x0
#define OPCODE_TEXT 0x1
#define OPCODE_BINARY 0x2
#define OPCODE_CLOSE 0x8
#define OPCODE_PING 0x9
#define OPCODE_PONG 0xA
#define STATE_INIT 0
#define STATE_START 1
#define STATE_LENGTH 2
#define STATE_DATA 3
#define STATE_CLOSED 4
struct websock {
int state;
uint64_t maxlength;
int lenhead, szhead;
uint64_t length;
uint32_t mask;
unsigned char header[14]; /* 2 + 8 + 4 */
const struct websock_itf *itf;
void *closure;
};
static ssize_t ws_writev(struct websock *ws, const struct iovec *iov, int iovcnt)
{
return ws->itf->writev(ws->closure, iov, iovcnt);
}
static ssize_t ws_readv(struct websock *ws, const struct iovec *iov, int iovcnt)
{
return ws->itf->readv(ws->closure, iov, iovcnt);
}
#if 0
static ssize_t ws_write(struct websock *ws, const void *buffer, size_t buffer_size)
{
struct iovec iov;
iov.iov_base = (void *)buffer; /* const cast */
iov.iov_len = buffer_size;
return ws_writev(ws, &iov, 1);
}
#endif
static ssize_t ws_read(struct websock *ws, void *buffer, size_t buffer_size)
{
struct iovec iov;
iov.iov_base = buffer;
iov.iov_len = buffer_size;
return ws_readv(ws, &iov, 1);
}
static ssize_t websock_send(struct websock *ws, unsigned char opcode,
const void *buffer, size_t buffer_size)
{
struct iovec iov[2];
size_t pos;
ssize_t rc;
unsigned char header[32];
if (ws->state == STATE_CLOSED)
return 0;
pos = 0;
header[pos++] = (unsigned char)(FRAME_SET_FIN(1) | FRAME_SET_OPCODE(opcode));
buffer_size = (uint64_t) buffer_size;
if (buffer_size < 126) {
header[pos++] =
FRAME_SET_MASK(0) | FRAME_SET_LENGTH(buffer_size, 0);
} else {
if (buffer_size < 65536) {
header[pos++] = FRAME_SET_MASK(0) | 126;
} else {
header[pos++] = FRAME_SET_MASK(0) | 127;
header[pos++] = FRAME_SET_LENGTH(buffer_size, 7);
header[pos++] = FRAME_SET_LENGTH(buffer_size, 6);
header[pos++] = FRAME_SET_LENGTH(buffer_size, 5);
header[pos++] = FRAME_SET_LENGTH(buffer_size, 4);
header[pos++] = FRAME_SET_LENGTH(buffer_size, 3);
header[pos++] = FRAME_SET_LENGTH(buffer_size, 2);
}
header[pos++] = FRAME_SET_LENGTH(buffer_size, 1);
header[pos++] = FRAME_SET_LENGTH(buffer_size, 0);
}
iov[0].iov_base = header;
iov[0].iov_len = pos;
iov[1].iov_base = (void *)buffer; /* const cast */
iov[1].iov_len = buffer_size;
rc = ws_writev(ws, iov, 1 + !!buffer_size);
if (opcode == OPCODE_CLOSE) {
ws->length = 0;
ws->state = STATE_CLOSED;
ws->itf->disconnect(ws->closure);
}
return rc;
}
void websock_close(struct websock *ws)
{
websock_send(ws, OPCODE_CLOSE, NULL, 0);
}
void websock_close_code(struct websock *ws, uint16_t code)
{
unsigned char buffer[2];
/* Send server-side closing handshake */
buffer[0] = (unsigned char)((code >> 8) & 0xFF);
buffer[1] = (unsigned char)(code & 0xFF);
websock_send(ws, OPCODE_CLOSE, buffer, 2);
}
void websock_ping(struct websock *ws)
{
websock_send(ws, OPCODE_PING, NULL, 0);
}
void websock_pong(struct websock *ws)
{
websock_send(ws, OPCODE_PONG, NULL, 0);
}
void websock_text(struct websock *ws, const char *text, size_t length)
{
websock_send(ws, OPCODE_TEXT, text, length);
}
void websock_binary(struct websock *ws, const void *data, size_t length)
{
websock_send(ws, OPCODE_BINARY, data, length);
}
static int read_header(struct websock *ws)
{
if (ws->lenhead < ws->szhead) {
ssize_t rbc =
ws_read(ws, &ws->header[ws->lenhead], (size_t)(ws->szhead - ws->lenhead));
if (rbc < 0)
return -1;
ws->lenhead += (int)rbc;
}
return 0;
}
int websock_dispatch(struct websock *ws)
{
loop:
switch (ws->state) {
case STATE_INIT:
ws->lenhead = 0;
ws->szhead = 2;
ws->state = STATE_START;
case STATE_START:
/* read the header */
if (read_header(ws))
return -1;
else if (ws->lenhead < ws->szhead)
return 0;
/* sanity checks */
if (FRAME_GET_RSV1(ws->header[0]) != 0)
goto protocol_error;
if (FRAME_GET_RSV2(ws->header[0]) != 0)
goto protocol_error;
if (FRAME_GET_RSV3(ws->header[0]) != 0)
goto protocol_error;
/* fast track */
switch (FRAME_GET_OPCODE(ws->header[0])) {
case OPCODE_CONTINUATION:
case OPCODE_TEXT:
case OPCODE_BINARY:
break;
case OPCODE_CLOSE:
if (FRAME_GET_MASK(ws->header[1]))
goto protocol_error;
if (FRAME_GET_PAYLOAD_LEN(ws->header[1]) == 1)
goto protocol_error;
if (FRAME_GET_PAYLOAD_LEN(ws->header[1]))
ws->szhead += 2;
break;
case OPCODE_PING:
if (FRAME_GET_MASK(ws->header[1]))
goto protocol_error;
if (FRAME_GET_PAYLOAD_LEN(ws->header[1]) != 0)
goto protocol_error;
if (ws->itf->on_ping)
ws->itf->on_ping(ws->closure);
else
websock_pong(ws);
ws->state = STATE_INIT;
goto loop;
case OPCODE_PONG:
if (FRAME_GET_MASK(ws->header[1]))
goto protocol_error;
if (FRAME_GET_PAYLOAD_LEN(ws->header[1]) != 0)
goto protocol_error;
if (ws->itf->on_pong)
ws->itf->on_pong(ws->closure);
ws->state = STATE_INIT;
goto loop;
default:
goto protocol_error;
}
/* update heading size */
switch (FRAME_GET_PAYLOAD_LEN(ws->header[1])) {
case 127:
ws->szhead += 6;
case 126:
ws->szhead += 2;
default:
ws->szhead += 4 * FRAME_GET_MASK(ws->header[1]);
}
ws->state = STATE_LENGTH;
case STATE_LENGTH:
/* continue to read the header */
if (read_header(ws))
return -1;
else if (ws->lenhead < ws->szhead)
return 0;
/* compute header values */
switch (FRAME_GET_PAYLOAD_LEN(ws->header[1])) {
case 127:
ws->length = (((uint64_t) ws->header[2]) << 56)
| (((uint64_t) ws->header[3]) << 48)
| (((uint64_t) ws->header[4]) << 40)
| (((uint64_t) ws->header[5]) << 32)
| (((uint64_t) ws->header[6]) << 24)
| (((uint64_t) ws->header[7]) << 16)
| (((uint64_t) ws->header[8]) << 8)
| (uint64_t) ws->header[9];
break;
case 126:
ws->length = (((uint64_t) ws->header[2]) << 8)
| (uint64_t) ws->header[3];
break;
default:
ws->length = FRAME_GET_PAYLOAD_LEN(ws->header[1]);
break;
}
if (ws->length > ws->maxlength)
goto too_long_error;
if (FRAME_GET_MASK(ws->header[1])) {
((unsigned char *)&ws->mask)[0] = ws->header[ws->szhead - 4];
((unsigned char *)&ws->mask)[1] = ws->header[ws->szhead - 3];
((unsigned char *)&ws->mask)[2] = ws->header[ws->szhead - 2];
((unsigned char *)&ws->mask)[3] = ws->header[ws->szhead - 1];
} else
ws->mask = 0;
ws->state = STATE_DATA;
switch (FRAME_GET_OPCODE(ws->header[0])) {
case OPCODE_CONTINUATION:
ws->itf->on_continue(ws->closure,
FRAME_GET_FIN(ws->header[0]),
(size_t) ws->length);
break;
case OPCODE_TEXT:
ws->itf->on_text(ws->closure,
FRAME_GET_FIN(ws->header[0]),
(size_t) ws->length);
break;
case OPCODE_BINARY:
ws->itf->on_binary(ws->closure,
FRAME_GET_FIN(ws->header[0]),
(size_t) ws->length);
break;
case OPCODE_CLOSE:
ws->state = STATE_CLOSED;
if (ws->length)
ws->itf->on_close(ws->closure,
(uint16_t)((((uint16_t) ws-> header[2]) << 8) | ((uint16_t) ws->header[3])),
(size_t) ws->length);
else
ws->itf->on_close(ws->closure,
STATUS_CODE_UNSET, 0);
ws->itf->disconnect(ws->closure);
return 0;
}
break;
case STATE_DATA:
if (ws->length)
return 0;
ws->state = STATE_INIT;
break;
case STATE_CLOSED:
return 0;
}
goto loop;
too_long_error:
websock_close_code(ws, STATUS_CODE_MESSAGE_TOO_LARGE);
return 0;
protocol_error:
websock_close_code(ws, STATUS_CODE_PROTOCOL_ERROR);
return 0;
}
ssize_t websock_read(struct websock * ws, void *buffer, size_t size)
{
uint32_t mask, *b32;
uint8_t m, *b8;
ssize_t rc;
if (ws->state != STATE_DATA && ws->state != STATE_CLOSED)
return 0;
if (size > ws->length)
size = (size_t) ws->length;
rc = ws_read(ws, buffer, size);
if (rc > 0) {
size = (size_t) rc;
ws->length -= size;
if (ws->mask) {
mask = ws->mask;
b8 = buffer;
while (size && ((sizeof(uint32_t) - 1) & (uintptr_t) b8)) {
m = ((uint8_t *) & mask)[0];
((uint8_t *) & mask)[0] = ((uint8_t *) & mask)[1];
((uint8_t *) & mask)[1] = ((uint8_t *) & mask)[2];
((uint8_t *) & mask)[2] = ((uint8_t *) & mask)[3];
((uint8_t *) & mask)[3] = m;
*b8++ ^= m;
size--;
}
b32 = (uint32_t *) b8;
while (size >= sizeof(uint32_t)) {
*b32++ ^= mask;
size -= sizeof(uint32_t);
}
b8 = (uint8_t *) b32;
while (size) {
m = ((uint8_t *) & mask)[0];
((uint8_t *) & mask)[0] = ((uint8_t *) & mask)[1];
((uint8_t *) & mask)[1] = ((uint8_t *) & mask)[2];
((uint8_t *) & mask)[2] = ((uint8_t *) & mask)[3];
((uint8_t *) & mask)[3] = m;
*b8++ ^= m;
size--;
}
ws->mask = mask;
}
}
return rc;
}
void websock_drop(struct websock *ws)
{
char buffer[4096];
while (ws->length && ws_read(ws, buffer, sizeof buffer) >= 0) ;
}
struct websock *websock_create(const struct websock_itf *itf, void *closure)
{
struct websock *result = calloc(1, sizeof *result);
if (result) {
result->itf = itf;
result->closure = closure;
result->maxlength = 65000;
}
return result;
}
void websock_destroy(struct websock *ws)
{
free(ws);
}
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