- struct sockaddr if_addr; /* internet address of interface */
- struct sockaddr if_broadaddr; /* broadcast address of interface */
+ struct sockaddr if_addr; /* address of interface */
+ union {
+ struct sockaddr ifu_broadaddr;
+ struct sockaddr ifu_dstaddr;
+ } if_ifu;
+#define if_broadaddr if_ifu.ifu_broadaddr /* broadcast address */
+#define if_dstaddr if_ifu.ifu_dstaddr /* other end of p-to-p link */