1 files changed, 75 insertions, 0 deletions
diff --git a/sbin/ipf/ifaddr.c b/sbin/ipf/ifaddr.c
new file mode 100644
index 00000000000..300e3e27f3e
--- /dev/null
+++ b/sbin/ipf/ifaddr.c
@@ -0,0 +1,75 @@
+/* $OpenBSD: ifaddr.c,v 1.1 1999/12/16 07:38:45 kjell Exp $ */
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <err.h>
+#include <stdlib.h>
+#include "ifaddr.h"
+
+
+/*
+ * if_addr():
+ *      given a string containing an interface name (e.g. "ppp0")
+ *      return the IP address it represents
+ *
+ * The OpenBSD community considers this feature to be quite useful and
+ * suggests inclusion into other platforms. The closest alternative is
+ * to define /etc/networks with suitable values.
+ */
+int     if_addr(name, ap)
+char            *name;
+struct in_addr  *ap;
+{
+        struct ifconf ifc;
+        struct ifreq ifreq, *ifr;
+        char *inbuf = NULL;
+        int s, i, len = 8192;
+
+        if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+                warn("socket");
+                return 0;
+        }
+
+        while (1) {
+                ifc.ifc_len = len;
+                ifc.ifc_buf = inbuf = realloc(inbuf, len);
+                if (inbuf == NULL)
+                        err(1, "malloc");
+                if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
+                        warn("SIOCGIFCONF");
+                        goto if_addr_lose;
+                }
+                if (ifc.ifc_len + sizeof(ifreq) < len)
+                        break;
+                len *= 2;
+        }
+        ifr = ifc.ifc_req;
+        ifreq.ifr_name[0] = '\0';
+        for (i = 0; i < ifc.ifc_len; ) {
+                ifr = (struct ifreq *)((caddr_t)ifc.ifc_req + i);
+                i += sizeof(ifr->ifr_name) +
+                        (ifr->ifr_addr.sa_len > sizeof(struct sockaddr)
+                                ? ifr->ifr_addr.sa_len
+                                : sizeof(struct sockaddr));
+                ifreq = *ifr;
+                if (ioctl(s, SIOCGIFADDR, (caddr_t)ifr) < 0)
+                        continue;
+                if (ifr->ifr_addr.sa_family != AF_INET)
+                        continue;
+                if (!strcmp(name, ifr->ifr_name)) {
+                        struct sockaddr_in *sin;
+                        close(s);
+                        free(inbuf);
+                        sin = (struct sockaddr_in *)&ifr->ifr_addr;
+                        *ap = sin->sin_addr;
+                        return (1);
+                }
+        }
+
+if_addr_lose:
+        close(s);
+        free(inbuf);
+        return 0;
+}