Function read_payload_header

connectd/websocketd.c:235–282

Returns payload size, sets inmask, is_binframe */

/* Returns payload size, sets inmask, is_binframe */
static size_t read_payload_header(int fd, u8 inmask[4], bool *is_binframe)
{
	/* Worst case header. */
	u8 frame_hdr[20];
	bool mask_set;
	size_t hdrsize = 2, len;

	/* First two bytes define hdr size. */
	if (!read_all(fd, frame_hdr, 2))
		exit(0);

	/* RFC-6455:
	 *  %x2 denotes a binary frame
	 */
	*is_binframe = ((frame_hdr[0] & 0x0F) == 2);
	mask_set = (frame_hdr[1] & 0x80);
	len = (frame_hdr[1] & 0x7f);

	if (len == 126)
		hdrsize += 2;
	else if (len == 127)
		hdrsize += 8;

	if (mask_set)
		hdrsize += 4;

	/* Read rest of hdr if necessary */
	if (hdrsize > 2 && !read_all(fd, frame_hdr + 2, hdrsize - 2))
		exit(0);

	if (len == 126) {
		be16 be16len;
		memcpy(&be16len, frame_hdr + 2, 2);
		len = be16_to_cpu(be16len);
	} else if (len == 127) {
		be64 be64len;
		memcpy(&be64len, frame_hdr + 2, 8);
		len = be64_to_cpu(be64len);
	}

	if (mask_set) {
		memcpy(inmask, frame_hdr + hdrsize - 4, 4);
		hdrsize += 4;
	} else
		memset(inmask, 0, 4);

	return len;
}

static void apply_mask(u8 *buf, size_t len, const u8 inmask[4])
{