Tools: hv: Represent the ipv6 mask using CIDR notation
K. Y. Srinivasan [Fri, 17 Aug 2012 01:32:17 +0000 (18:32 -0700)]
Transform ipv6 subnet information to CIDR notation.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/hv/hv_kvp_daemon.c

index de1724c..a63e83a 100644 (file)
@@ -491,6 +491,15 @@ done:
        return;
 }
 
+static unsigned int hweight32(unsigned int *w)
+{
+       unsigned int res = *w - ((*w >> 1) & 0x55555555);
+       res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
+       res = (res + (res >> 4)) & 0x0F0F0F0F;
+       res = res + (res >> 8);
+       return (res + (res >> 16)) & 0x000000FF;
+}
+
 static int kvp_process_ip_address(void *addrp,
                                int family, char *buffer,
                                int length,  int *offset)
@@ -535,10 +544,15 @@ kvp_get_ip_address(int family, char *if_name, int op,
        struct ifaddrs *curp;
        int offset = 0;
        int sn_offset = 0;
-       const char *str;
        int error = 0;
        char *buffer;
        struct hv_kvp_ipaddr_value *ip_buffer;
+       char cidr_mask[5]; /* /xyz */
+       int weight;
+       int i;
+       unsigned int *w;
+       char *sn_str;
+       struct sockaddr_in6 *addr6;
 
        if (op == KVP_OP_ENUMERATE) {
                buffer = out_buffer;
@@ -611,18 +625,30 @@ kvp_get_ip_address(int family, char *if_name, int op,
                                        goto gather_ipaddr;
                        } else {
                                ip_buffer->addr_family |= ADDR_FAMILY_IPV6;
+
                                /*
-                                * Get subnet info.
+                                * Get subnet info in CIDR format.
                                 */
-                               error = kvp_process_ip_address(
-                                                            curp->ifa_netmask,
-                                                            AF_INET6,
-                                                            (char *)
-                                                            ip_buffer->sub_net,
-                                                            length,
-                                                            &sn_offset);
-                               if (error)
+                               weight = 0;
+                               sn_str = (char *)ip_buffer->sub_net;
+                               addr6 = (struct sockaddr_in6 *)
+                                       curp->ifa_netmask;
+                               w = addr6->sin6_addr.s6_addr32;
+
+                               for (i = 0; i < 4; i++)
+                                       weight += hweight32(&w[i]);
+
+                               sprintf(cidr_mask, "/%d", weight);
+                               if ((length - sn_offset) <
+                                       (strlen(cidr_mask) + 1))
                                        goto gather_ipaddr;
+
+                               if (sn_offset == 0)
+                                       strcpy(sn_str, cidr_mask);
+                               else
+                                       strcat(sn_str, cidr_mask);
+                               strcat((char *)ip_buffer->sub_net, ";");
+                               sn_offset += strlen(sn_str) + 1;
                        }
                }