(minimal) libcoap client example

main.c

#include "libcoap/coap.h"
#include <arpa/inet.h>
#include <stdio.h>

int main() {


  struct sockaddr_in6 sa_dst;

  // clear memory
  memset(&sa_dst, 0, sizeof(struct sockaddr_in6 ));

  // write byte representation to sin6_addr
  inet_pton(AF_INET6, "::1", &(sa_dst.sin6_addr));

  // set network family to ipv6
  sa_dst.sin6_family = AF_INET6;

  // set port to COAP_DEFAULT_PORT
  sa_dst.sin6_port = htons(COAP_DEFAULT_PORT);

  coap_address_t coap_dst;

  coap_address_init(&coap_dst);

  coap_dst.size = sizeof(struct sockaddr_in6); // is this right?

  coap_dst.addr.sin6 = sa_dst; // is this right?

  // create src address

  struct sockaddr_in6 sa_src;

  // clear memory
  memset(&sa_src, 0, sizeof(struct sockaddr_in6));

  // write byte representation to sin6_addr
  // source of package is localhost aka ::1
  inet_pton(AF_INET6, "::1", &(sa_src.sin6_addr));

  // set network family to ipv6
  sa_src.sin6_family = AF_INET6;

  // set src port to 8888 TODO how do we find a good source port?
  sa_src.sin6_port = htons(8888);

  coap_address_t coap_src;

  coap_address_init(&coap_src);

  coap_src.size = sizeof(struct sockaddr_in6); // is this right?

  coap_src.addr.sin6 = sa_src; // is this right?

  // create context from src address

  coap_context_t *context = NULL;

  context = coap_new_context(&coap_src);

  // send the request

  const unsigned char payload[20] = "Hello World";

  coap_pdu_t *pdu;

  pdu = coap_pdu_init(COAP_MESSAGE_NON, 0x01, COAP_INVALID_TID, 128);

  if(pdu == NULL) {
    printf("Somthing went wrong in pdu_init\n");
    // something went wrong
    return 1;
  }

  // do not add payload for now
  // coap_add_data(pdu, 12, payload);

  coap_send(context, context->endpoint, &coap_dst, pdu);

  coap_delete_pdu(pdu);
  coap_free_context(context);

  return 0;
}