coap_ws_internal.h

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/*
 * coap_ws_internal.h -- WebSockets Transport Layer Support for libcoap
 *
 * Copyright (C) 2023-2025 Olaf Bergmann <bergmann@tzi.org>
 * Copyright (C) 2023-2025 Jon Shallow <supjps-libcoap@jpshallow.com>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * This file is part of the CoAP library libcoap. Please see README for terms
 * of use.
 */
 
#ifndef COAP_WS_INTERNAL_H_
#define COAP_WS_INTERNAL_H_
 
#include "coap_internal.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* Frame size:  Min Header + (Opt) Ext payload length + (Opt) Masking key */
#define COAP_MAX_FS (2 + 8 + 4)
 
typedef struct coap_ws_state_t {
  coap_session_type_t state; 
  uint8_t up;           
  uint8_t seen_first;   
  uint8_t seen_host;    
  uint8_t seen_upg;     
  uint8_t seen_conn;    
  uint8_t seen_key;     
  uint8_t seen_proto;   
  uint8_t seen_ver;     
  uint8_t sent_close;   
  uint8_t recv_close;   
  uint16_t close_reason; 
  int all_hdr_in;       
  int hdr_ofs;          
  uint8_t rd_header[COAP_MAX_FS]; 
  uint8_t mask_key[4];  
  uint32_t http_ofs;    
  uint8_t http_hdr[160]; 
  size_t data_ofs;      
  size_t data_size;     
  uint8_t key[16];      
} coap_ws_state_t;
 
/*
 * WebSockets Frame
 *
 *    0                   1                   2                   3
 *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *   +-+-+-+-+-------+-+-------------+-------------------------------+
 *   |F|R|R|R| opcode|M| Payload len |    Extended payload length    |
 *   |I|S|S|S|  (4)  |A|     (7)     |             (16/64)           |
 *   |N|V|V|V|       |S|             |   (if payload len==126/127)   |
 *   | |1|2|3|       |K|             |                               |
 *   +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
 *   |     Extended payload length continued, if payload len == 127  |
 *   + - - - - - - - - - - - - - - - +-------------------------------+
 *   |                               |Masking-key, if MASK set to 1  |
 *   +-------------------------------+-------------------------------+
 *   | Masking-key (continued)       |          Payload Data         |
 *   +-------------------------------- - - - - - - - - - - - - - - - +
 *   :                     Payload Data continued ...                :
 *   + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
 *   |                     Payload Data continued ...                |
 *   +---------------------------------------------------------------+
 */
 
#define WS_B0_FIN_BIT  0x80
#define WS_B0_RSV_MASK 0x70
#define WS_B0_OP_MASK  0x0f
 
#define WS_B1_MASK_BIT 0x80
#define WS_B1_LEN_MASK 0x7f
 
typedef enum {
  WS_OP_CONT = 0x0,
  WS_OP_TEXT,
  WS_OP_BINARY,
  WS_OP_CLOSE = 0x8,
  WS_OP_PING,
  WS_OP_PONG
} coap_ws_opcode_t;
 
ssize_t coap_ws_write(coap_session_t *session,
                      const uint8_t *data, size_t datalen);
 
ssize_t coap_ws_read(coap_session_t *session, uint8_t *data,
                     size_t datalen);
 
void coap_ws_establish(coap_session_t *session);
 
void coap_ws_close(coap_session_t *session);
 
#ifdef __cplusplus
}
#endif
 
#endif /* COAP_WS_INTERNAL_H */