commit 6ee3ecc03a7cf9118e6a0b2577f15c76244bc408
author Chris Dearman <chris@mips.com> Fri Jun 17 17:07:46 2011 -0700
committer Dmitry Shmidt <dimitrysh@google.com> Wed Aug 08 15:50:03 2012 -0700
tree 2bc6d882fe24ba7ec4cca5db72068fa41fa914d5
parent ff5c802e6ce489a36ac28e3d93b7e8541b3e4d81

Decode DHCP netmask option correctly

Signed-off-by: Chris Dearman <chris@mips.com>
Change-Id: Ibc288458baf2f75c5b19a46e4c97ee59521cc9a5

libnetutils/dhcpclient.c

diff --git a/libnetutils/dhcpclient.c b/libnetutils/dhcpclient.c
index b38e258..34500e7 100644
--- a/libnetutils/dhcpclient.c
+++ b/libnetutils/dhcpclient.c
@@ -197,7 +197,11 @@
         }
         switch(opt) {
         case OPT_SUBNET_MASK:
-            if (optlen >= 4) info->prefixLength = ipv4NetmaskToPrefixLength(*((uint32_t*)x));
+            if (optlen >= 4) {
+                in_addr_t mask;
+                memcpy(&mask, x, 4);
+                info->prefixLength = ipv4NetmaskToPrefixLength(mask);
+            }
             break;
         case OPT_GATEWAY:
             if (optlen >= 4) memcpy(&info->gateway, x, 4);

libnetutils/ifc_utils.c

diff --git a/libnetutils/ifc_utils.c b/libnetutils/ifc_utils.c
index 50095ab..eb33d06 100644
--- a/libnetutils/ifc_utils.c
+++ b/libnetutils/ifc_utils.c
@@ -75,9 +75,8 @@
 
 int ipv4NetmaskToPrefixLength(in_addr_t mask)
 {
-    mask = ntohl(mask);
     int prefixLength = 0;
-    uint32_t m = (uint32_t)mask;
+    uint32_t m = (uint32_t)ntohl(mask);
     while (m & 0x80000000) {
         prefixLength++;
         m = m << 1;
@@ -486,7 +485,7 @@
         if(ioctl(ifc_ctl_sock, SIOCGIFNETMASK, &ifr) < 0) {
             *prefixLength = 0;
         } else {
-            *prefixLength = ipv4NetmaskToPrefixLength((int)
+            *prefixLength = ipv4NetmaskToPrefixLength(
                     ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr);
         }
     }