Leave it up to the platform-dependent "get interface list" code to

[libpcap] / fad-getad.c

diff --git a/fad-getad.c b/fad-getad.c
index 7ffd48474ca1d8f57328b367c84d96b1acd0d2ab..bb2395c033f64fb7e77f0485f8055a1334219078 100644 (file)
--- a/fad-getad.c
+++ b/fad-getad.c
@@ -34,7 +34,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/fad-getad.c,v 1.1 2002-07-27 18:46:21 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/fad-getad.c,v 1.2 2002-07-30 08:12:13 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -55,6 +55,37 @@ static const char rcsid[] =
 #include "os-proto.h"
 #endif
 
+/*
+ * This is fun.
+ *
+ * In older BSD systems, socket addresses were fixed-length, and
+ * "sizeof (struct sockaddr)" gave the size of the structure.
+ * All addresses fit within a "struct sockaddr".
+ *
+ * In newer BSD systems, the socket address is variable-length, and
+ * there's an "sa_len" field giving the length of the structure;
+ * this allows socket addresses to be longer than 2 bytes of family
+ * and 14 bytes of data.
+ *
+ * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
+ * variant of the old BSD scheme (with "struct sockaddr_storage" rather
+ * than "struct sockaddr"), and some use the new BSD scheme.
+ *
+ * GNU libc uses neither scheme, but has an "SA_LEN()" macro that
+ * determines the size based on the address family.
+ */
+#ifndef SA_LEN
+#ifdef HAVE_SOCKADDR_SA_LEN
+#define SA_LEN(addr)   ((addr)->sa_len)
+#else /* HAVE_SOCKADDR_SA_LEN */
+#ifdef HAVE_SOCKADDR_STORAGE
+#define SA_LEN(addr)   (sizeof (struct sockaddr_storage))
+#else /* HAVE_SOCKADDR_STORAGE */
+#define SA_LEN(addr)   (sizeof (struct sockaddr))
+#endif /* HAVE_SOCKADDR_STORAGE */
+#endif /* HAVE_SOCKADDR_SA_LEN */
+#endif /* SA_LEN */
+
 /*
  * Get a list of all interfaces that are up and that we can open.
  * Returns -1 on error, 0 otherwise.
@@ -69,6 +100,7 @@ pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
        pcap_if_t *devlist = NULL;
        struct ifaddrs *ifap, *ifa;
        struct sockaddr *broadaddr, *dstaddr;
+       size_t broadaddr_size, dstaddr_size;
        int ret = 0;
 
        /*
@@ -108,21 +140,29 @@ pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
                 * non-null on a non-point-to-point
                 * interface.
                 */
-               if (ifa->ifa_flags & IFF_BROADCAST)
+               if (ifa->ifa_flags & IFF_BROADCAST) {
                        broadaddr = ifa->ifa_broadaddr;
-               else
+                       broadaddr_size = SA_LEN(broadaddr);
+               } else {
                        broadaddr = NULL;
-               if (ifa->ifa_flags & IFF_POINTOPOINT)
+                       broadaddr_size = 0;
+               }
+               if (ifa->ifa_flags & IFF_POINTOPOINT) {
                        dstaddr = ifa->ifa_dstaddr;
-               else
+                       dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
+               } else {
                        dstaddr = NULL;
+                       dstaddr_size = 0;
+               }
 
                /*
                 * Add information for this address to the list.
                 */
                if (add_addr_to_iflist(&devlist, ifa->ifa_name,
-                   ifa->ifa_flags, ifa->ifa_addr, ifa->ifa_netmask,
-                   broadaddr, dstaddr, errbuf) < 0) {
+                   ifa->ifa_flags, ifa->ifa_addr, SA_LEN(ifa->ifa_addr),
+                   ifa->ifa_netmask, SA_LEN(ifa->ifa_netmask),
+                   broadaddr, broadaddr_size, dstaddr, dstaddr_size,
+                   errbuf) < 0) {
                        ret = -1;
                        break;
                }