mirror of
https://github.com/obgm/libcoap.git
synced 2026-11-07 10:12:53 +03:00
jcmichelou
bcfd7a0753
Make coap_pdu-t independent of the header style. Use C99 sized types when applicable. Use transaction ids in host byte order in the library. Make coap_pdu_t payload storage grow on demand. Add parsing and encoding of PDUs with UDP or TCP style headers. Adapt examples and unit tests to the new PDU format.
137 lines
4.5 KiB
C
137 lines
4.5 KiB
C
/*
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* block.h -- block transfer
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*
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* Copyright (C) 2010-2012,2014-2015 Olaf Bergmann <bergmann@tzi.org>
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*
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* This file is part of the CoAP library libcoap. Please see README for terms
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* of use.
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*/
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#ifndef _COAP_BLOCK_H_
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#define _COAP_BLOCK_H_
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#include "encode.h"
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#include "option.h"
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#include "pdu.h"
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/**
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* @defgroup block Block Transfer
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* @{
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*/
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#ifndef COAP_MAX_BLOCK_SZX
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/**
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* The largest value for the SZX component in a Block option.
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*/
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#define COAP_MAX_BLOCK_SZX 6
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#endif /* COAP_MAX_BLOCK_SZX */
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/**
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* Structure of Block options.
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*/
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typedef struct {
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unsigned int num; /**< block number */
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unsigned int m:1; /**< 1 if more blocks follow, 0 otherwise */
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unsigned int szx:3; /**< block size */
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} coap_block_t;
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/**
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* Returns the value of the least significant byte of a Block option @p opt.
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* For zero-length options (i.e. num == m == szx == 0), COAP_OPT_BLOCK_LAST
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* returns @c NULL.
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*/
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#define COAP_OPT_BLOCK_LAST(opt) \
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(coap_opt_length(opt) ? (coap_opt_const_value(opt) + (coap_opt_length(opt)-1)) : 0)
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/** Returns the value of the More-bit of a Block option @p opt. */
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#define COAP_OPT_BLOCK_MORE(opt) \
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(coap_opt_length(opt) ? (*COAP_OPT_BLOCK_LAST(opt) & 0x08) : 0)
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/** Returns the value of the SZX-field of a Block option @p opt. */
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#define COAP_OPT_BLOCK_SZX(opt) \
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(coap_opt_length(opt) ? (*COAP_OPT_BLOCK_LAST(opt) & 0x07) : 0)
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/**
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* Returns the value of field @c num in the given block option @p block_opt.
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*/
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unsigned int coap_opt_block_num(const coap_opt_t *block_opt);
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/**
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* Checks if more than @p num blocks are required to deliver @p data_len
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* bytes of data for a block size of 1 << (@p szx + 4).
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*/
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COAP_STATIC_INLINE int
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coap_more_blocks(size_t data_len, unsigned int num, uint16_t szx) {
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return ((num+1) << (szx + 4)) < data_len;
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}
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/** Sets the More-bit in @p block_opt */
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COAP_STATIC_INLINE void
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coap_opt_block_set_m(coap_opt_t *block_opt, int m) {
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if (m)
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*(coap_opt_value(block_opt) + (coap_opt_length(block_opt) - 1)) |= 0x08;
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else
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*(coap_opt_value(block_opt) + (coap_opt_length(block_opt) - 1)) &= ~0x08;
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}
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/**
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* Initializes @p block from @p pdu. @p type must be either COAP_OPTION_BLOCK1
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* or COAP_OPTION_BLOCK2. When option @p type was found in @p pdu, @p block is
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* initialized with values from this option and the function returns the value
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* @c 1. Otherwise, @c 0 is returned.
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*
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* @param pdu The pdu to search for option @p type.
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* @param type The option to search for (must be COAP_OPTION_BLOCK1 or
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* COAP_OPTION_BLOCK2).
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* @param block The block structure to initilize.
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*
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* @return @c 1 on success, @c 0 otherwise.
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*/
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int coap_get_block(coap_pdu_t *pdu, uint16_t type, coap_block_t *block);
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/**
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* Writes a block option of type @p type to message @p pdu. If the requested
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* block size is too large to fit in @p pdu, it is reduced accordingly. An
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* exception is made for the final block when less space is required. The actual
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* length of the resource is specified in @p data_length.
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*
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* This function may change *block to reflect the values written to @p pdu. As
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* the function takes into consideration the remaining space @p pdu, no more
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* options should be added after coap_write_block_opt() has returned.
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*
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* @param block The block structure to use. On return, this object is
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* updated according to the values that have been written to
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* @p pdu.
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* @param type COAP_OPTION_BLOCK1 or COAP_OPTION_BLOCK2.
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* @param pdu The message where the block option should be written.
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* @param data_length The length of the actual data that will be added the @p
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* pdu by calling coap_add_block().
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*
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* @return @c 1 on success, or a negative value on error.
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*/
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int coap_write_block_opt(coap_block_t *block,
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uint16_t type,
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coap_pdu_t *pdu,
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size_t data_length);
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/**
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* Adds the @p block_num block of size 1 << (@p block_szx + 4) from source @p
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* data to @p pdu.
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*
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* @param pdu The message to add the block.
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* @param len The length of @p data.
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* @param data The source data to fill the block with.
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* @param block_num The actual block number.
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* @param block_szx Encoded size of block @p block_number.
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*
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* @return @c 1 on success, @c 0 otherwise.
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*/
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int coap_add_block(coap_pdu_t *pdu,
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unsigned int len,
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const unsigned char *data,
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unsigned int block_num,
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unsigned char block_szx);
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/**@}*/
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#endif /* _COAP_BLOCK_H_ */
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