Fix potential type size mismatch through pointers

size_t can be 64-bits while unsigned int is smaller. This causes issues
when option_length is accessed through the pointer x in
coap_parse_message(). The option length and delta are at most a 16-bit
unsigned integer plus 269 according to RFC 7252. Changing
option_number, option_delta, and option_length to uint32_t and x to
uint32_t * fixes eclipse-wakaama#429. This also ensures sufficient size even if used
on a platform with smaller integers.

Signed-off-by: Scott Bertin <[email protected]>

core/er-coap-13/er-coap-13.c

@@ -617,10 +617,10 @@ coap_parse_message(void *packet, uint8_t *data, uint16_t data_len)
 {
   coap_packet_t *const coap_pkt = (coap_packet_t *) packet;
   uint8_t *current_option;
-  unsigned int option_number = 0;
-  unsigned int option_delta = 0;
-  size_t option_length = 0;
-  unsigned int *x;
+  uint32_t option_number = 0;
+  uint32_t option_delta = 0;
+  uint32_t option_length = 0;
+  uint32_t *x;
 
   /* Initialize packet */
   memset(coap_pkt, 0, sizeof(coap_packet_t));