mirror of
https://github.com/obgm/libcoap.git
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94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
/* pdu.c -- CoAP message structure
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*
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* (c) 2010 Olaf Bergmann <bergmann@tzi.org>
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "debug.h"
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#include "pdu.h"
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coap_pdu_t *
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coap_new_pdu() {
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coap_pdu_t *pdu = malloc( sizeof(coap_pdu_t) + COAP_MAX_PDU_SIZE );
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if (!pdu) {
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perror("new_pdu: malloc");
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return NULL;
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}
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/* initialize PDU */
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memset(pdu, 0, sizeof(coap_pdu_t) + COAP_MAX_PDU_SIZE );
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pdu->hdr = (coap_hdr_t *) ( (unsigned char *)pdu + sizeof(coap_pdu_t) );
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pdu->hdr->version = COAP_DEFAULT_VERSION;
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/* data points after the header; when options are added, the data
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pointer is moved to the back */
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pdu->length = sizeof(coap_hdr_t);
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pdu->data = (unsigned char *)pdu->hdr + pdu->length;
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return pdu;
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}
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void
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coap_delete_pdu(coap_pdu_t *pdu) {
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free( pdu );
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}
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#define options_start(p) ((coap_opt_t *) ( (unsigned char *)p->hdr + sizeof ( coap_hdr_t ) ))
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int
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coap_add_option(coap_pdu_t *pdu, unsigned char type, unsigned int len, const unsigned char *data) {
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unsigned char cnt;
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coap_opt_t *opt;
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unsigned char opt_code = 0;
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if (!pdu)
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return -1;
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/* get last option from pdu to calculate the delta */
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opt = options_start( pdu );
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for ( cnt = pdu->hdr->optcnt; cnt; --cnt ) {
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opt_code += COAP_OPT_DELTA(*opt);
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opt = (coap_opt_t *)( (unsigned char *)opt + COAP_OPT_SIZE(*opt) );
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}
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if ( type < opt_code ) {
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#ifndef NDEBUG
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fprintf(stderr, "options not added in correct order\n");
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#endif
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return -1;
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}
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/* create new option after last existing option */
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pdu->hdr->optcnt += 1;
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COAP_OPT_SETDELTA( *opt, type - opt_code );
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COAP_OPT_SETLENGTH( *opt, len );
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memcpy(COAP_OPT_VALUE(*opt), data, len);
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pdu->data = (unsigned char *)COAP_OPT_VALUE(*opt) + len ;
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pdu->length = pdu->data - (unsigned char *)pdu->hdr;
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return len;
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}
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int
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coap_add_data(coap_pdu_t *pdu, unsigned int len, const unsigned char *data) {
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if ( !pdu )
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return 0;
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if ( pdu->length + len > COAP_MAX_PDU_SIZE ) {
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#ifndef NDEBUG
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fprintf(stderr, "coap_add_data: cannot add: data too large for PDU\n");
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#endif
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return 0;
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}
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memcpy( (unsigned char *)pdu->hdr + pdu->length, data, len );
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pdu->length += len;
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return 1;
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}
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