1 /* inet_netof.c 4.3 82/11/14 */ 2 3 #include <sys/types.h> 4 #include <netinet/in.h> 5 6 /* 7 * Return the network number from an internet 8 * address; handles class a/b/c network #'s. 9 */ 10 inet_netof(in) 11 struct in_addr in; 12 { 13 register u_long i = ntohl(in.s_addr); 14 15 if (IN_CLASSA(i)) 16 return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT); 17 else if (IN_CLASSB(i)) 18 return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT); 19 else 20 return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT); 21 } 22