address.[hc]: Add convenience functions to get/set port

The layout of struct coap_address_t is platform-dependent. This
change introduces getter/setter functions to retrieve and modify
the port component:

   uint16_t coap_address_get_port(const coap_address_t *addr)
   void coap_address_set_port(coap_address_t *addr, uint16_t port)

The respective port is given in host byte order and will be
converted to/from network byte order automatically.

include/coap2/address.h

@@ -30,6 +30,22 @@ typedef struct coap_address_t {
   ip_addr_t addr;
 } coap_address_t;
 
+/**
+ * Returns the port from @p addr in host byte order.
+ */
+COAP_STATIC_INLINE uint16_t
+coap_address_get_port(const coap_address_t *addr) {
+  return ntohs(addr->port);
+}
+
+/**
+ * Sets the port field of @p addr to @p port (in host byte order).
+ */
+COAP_STATIC_INLINE void
+coap_address_set_port(coap_address_t *addr, uint16_t port) {
+  addr->port = htons(port);
+}
+
 #define _coap_address_equals_impl(A, B) \
         ((A)->port == (B)->port        \
         && (!!ip_addr_cmp(&(A)->addr,&(B)->addr)))
@@ -47,6 +63,22 @@ typedef struct coap_address_t {
   uint16_t port;
 } coap_address_t;
 
+/**
+ * Returns the port from @p addr in host byte order.
+ */
+COAP_STATIC_INLINE uint16_t
+coap_address_get_port(const coap_address_t *addr) {
+  return uip_ntohs(addr->port);
+}
+
+/**
+ * Sets the port field of @p addr to @p port (in host byte order).
+ */
+COAP_STATIC_INLINE void
+coap_address_set_port(coap_address_t *addr, uint16_t port) {
+  addr->port = uip_htons(port);
+}
+
 #define _coap_address_equals_impl(A,B) \
         ((A)->port == (B)->port        \
         && uip_ipaddr_cmp(&((A)->addr),&((B)->addr)))
@@ -68,6 +100,16 @@ typedef struct coap_address_t {
   } addr;
 } coap_address_t;
 
+/**
+ * Returns the port from @p addr in host byte order.
+ */
+uint16_t coap_address_get_port(const coap_address_t *addr);
+
+/**
+ * Set the port field of @p addr to @p port (in host byte order).
+ */
+void coap_address_set_port(coap_address_t *addr, uint16_t port);
+
 /**
  * Compares given address objects @p a and @p b. This function returns @c 1 if
  * addresses are equal, @c 0 otherwise. The parameters @p a and @p b must not be

src/address.c

@@ -27,6 +27,33 @@
 #define IN_MULTICAST(Address) (0)
 #endif /* RIOT_VERSION */
 
+uint16_t
+coap_address_get_port(const coap_address_t *addr) {
+  assert(addr != NULL);
+  switch (addr->addr.sa.sa_family) {
+  case AF_INET: return ntohs(addr->addr.sin.sin_port);
+  case AF_INET6: return ntohs(addr->addr.sin6.sin6_port);
+  default: /* undefined */
+    ;
+  }
+  return 0;
+}
+
+void
+coap_address_set_port(coap_address_t *addr, uint16_t port) {
+  assert(addr != NULL);
+  switch (addr->addr.sa.sa_family) {
+  case AF_INET:
+    addr->addr.sin.sin_port = htons(port);
+    break;
+  case AF_INET6:
+    addr->addr.sin6.sin6_port = htons(port);
+    break;
+  default: /* undefined */
+    ;
+  }
+}
+
 int
 coap_address_equals(const coap_address_t *a, const coap_address_t *b) {
   assert(a); assert(b);