coap_ext.c

/*
 * Copyright (C) 2015 HAW Hamburg
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */

/**
 * @{
 *
 * @file
 * @brief       extensions to stock microcoap (might become PRs)
 *
 * @author      Lotte Steenbrink <lotte.steenbrink@haw-hamburg.de>
 *
 * @}
 */

#include "coap_ext.h"

#define ENABLE_DEBUG    (0)
#include "debug.h"

const coap_endpoint_t endpoints[] =
{
    {(coap_method_t)0, NULL, NULL, NULL} /* marks the end of the endpoints array */
};

int seqnum = 12345;

// TODO: use rw_buf?
/**
Build a PUT request.
The value of buflen will be the request packet's size after successful completion.
*/
int coap_ext_build_PUT(uint8_t *buf, size_t *buflen,
                       const char *payload, const coap_endpoint_path_t *path)
{
    /*
     * Note: the resource URI is coded as an option! -> COAP_OPTION_URI_PATH
     */

    seqnum++;

    DEBUG("creating PUT request...\n");
    size_t req_pkt_sz;
    int errcode;
    int segment_count = path->count;

    /* cobble together CoAP header */
    coap_header_t req_hdr = {
        .ver = 1,
        .t = COAP_TYPE_CON,
        .tkl = 0,                                  /* microcoap can't generate tokens anyway */
        .code = MAKE_RSPCODE(0, COAP_METHOD_PUT),  /* class 0, detail 1: this is a PUT. */
        .id = {seqnum,22}                              /* TODO: create dynamic ID (seqnum style?) */
    };

    coap_buffer_t payload_buf = {
        .p = (const uint8_t *) payload,
        .len = strlen(payload)
    };

    coap_packet_t req_pkt = {
        .hdr = req_hdr,
        .tok = (coap_buffer_t) {},  /* No token */
        .numopts = segment_count,   /* all segments of the path to the resource */
        .payload = payload_buf
    };

    /* Create one option for each segment of the URI path and fill req_pkt.opts*/
    for (int i=0; i < segment_count; i++ ) {
        coap_option_t path_option = {
            .num = COAP_OPTION_URI_PATH,
            .buf = {.p = (const uint8_t *) path->elems[i],
                    .len = strlen(path->elems[i])}
        };

        req_pkt.opts[i] = path_option;
    }

    req_pkt_sz = sizeof(req_pkt);

    if (*buflen < req_pkt_sz) {
        DEBUG("Error: buflen too small:\n\tbuflen:%d\n\treq_pkt_sz:%d\n", *buflen, req_pkt_sz);
        return -1;
    }

#ifdef DEBUG
    DEBUG("[main-posix] content:\n");
    coap_dumpPacket(&req_pkt);
#endif

    // try to  write packet to send buffer
    if (0 != (errcode = coap_build(buf, buflen, &req_pkt))) {
        DEBUG("Error building packet! Error code: %i\nAborting. \n", errcode);
        return -1;
    }
    return 0;
}