2 * Check if an address belongs to the local system. Adapted from:
4 * pmap_svc.c 1.32 91/03/11 Copyright 1984,1990 Sun Microsystems, Inc.
5 * get_myaddress.c 2.1 88/07/29 4.0 RPCSRC.
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38 #include <sys/types.h>
39 #include <sys/socket.h>
43 #include <netinet/in.h>
45 #include <sys/ioctl.h>
56 * With virtual hosting, each hardware network interface can have multiple
57 * network addresses. On such machines the number of machine addresses can
58 * be surprisingly large.
62 static struct in_addr *addrs;
64 /* grow_addrs - extend list of local interface addresses */
66 static int grow_addrs(void)
68 struct in_addr *new_addrs;
72 * Keep the previous result if we run out of memory. The system would
73 * really get hosed if we simply give up.
75 new_num = (addrs == 0) ? 1 : num_addrs + num_addrs;
76 new_addrs = (struct in_addr *) malloc(sizeof(*addrs) * new_num);
78 perror("portmap: out of memory");
82 memcpy((char *) new_addrs, (char *) addrs,
83 sizeof(*addrs) * num_addrs);
92 /* find_local - find all IP addresses for this host */
100 struct ifreq *the_end;
105 * Get list of network interfaces. We use a huge buffer to allow for the
106 * presence of non-IP interfaces.
109 if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
113 ifc.ifc_len = sizeof(buf);
115 if (ioctl(sock, SIOCGIFCONF, (char *) &ifc) < 0) {
116 perror("SIOCGIFCONF");
120 /* Get IP address of each active IP network interface. */
122 the_end = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
124 for (ifr = ifc.ifc_req; ifr < the_end; ifr++) {
125 if (ifr->ifr_addr.sa_family == AF_INET) { /* IP net interface */
127 if (ioctl(sock, SIOCGIFFLAGS, (char *) &ifreq) < 0) {
128 perror("SIOCGIFFLAGS");
129 } else if (ifreq.ifr_flags & IFF_UP) { /* active interface */
130 if (ioctl(sock, SIOCGIFADDR, (char *) &ifreq) < 0) {
131 perror("SIOCGIFADDR");
133 if (num_local >= num_addrs)
134 if (grow_addrs() == 0)
136 addrs[num_local++] = ((struct sockaddr_in *)
137 & ifreq.ifr_addr)->sin_addr;
141 /* Support for variable-length addresses. */
143 ifr = (struct ifreq *) ((caddr_t) ifr
144 + ifr->ifr_addr.sa_len - sizeof(struct sockaddr));
151 /* from_local - determine whether request comes from the local system */
153 int from_local(struct sockaddr_in *addr)
157 if (addrs == 0 && find_local() == 0)
158 syslog(LOG_ERR, "cannot find any active local network interfaces");
160 for (i = 0; i < num_local; i++) {
161 if (memcmp((char *) &(addr->sin_addr), (char *) &(addrs[i]),
162 sizeof(struct in_addr)) == 0)
165 /* maybe a new interface was added */
169 for (i = 0; i < num_local; i++) {
170 if (memcmp((char *) &(addr->sin_addr), (char *) &(addrs[i]),
171 sizeof(struct in_addr)) == 0)
186 for (i = 0; i < num_local; i++)
187 printf("%s\n", inet_ntoa(addrs[i]));