netdev-linux: Fix aliasing error.

The latest version of GCC flags a common socket convention as breaking
strict-aliasing rules.  This commit removes the aliasing and gets rid of
the scary warning.

diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 0dff5082bfe9a5e8e1d1afcf4a09f9944e4934a3..18d327425a8afd46f6e12552f41c5f3cb40828e4 100644 (file)
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -1710,14 +1710,14 @@ netdev_linux_arp_lookup(const struct netdev *netdev,
                         uint32_t ip, uint8_t mac[ETH_ADDR_LEN])
 {
     struct arpreq r;
-    struct sockaddr_in *pa;
+    struct sockaddr_in sin;
     int retval;
 
     memset(&r, 0, sizeof r);
-    pa = (struct sockaddr_in *) &r.arp_pa;
-    pa->sin_family = AF_INET;
-    pa->sin_addr.s_addr = ip;
-    pa->sin_port = 0;
+    sin.sin_family = AF_INET;
+    sin.sin_addr.s_addr = ip;
+    sin.sin_port = 0;
+    memcpy(&r.arp_pa, &sin, sizeof sin);
     r.arp_ha.sa_family = ARPHRD_ETHER;
     r.arp_flags = 0;
     strncpy(r.arp_dev, netdev->name, sizeof r.arp_dev);