unix, win: add netmask to uv_interface_address

Include the netmask when returning information about the OS network
interfaces.

This commit provides implementations for windows and those unix
platforms using getifaddrs().

AIX was not implemented because it requires the use of ioctls and I do
not have an AIX development/test environment.  The windows code was
developed using mingw on winxp as I do not have access to visual studio.

Tested on darwin (ipv4/ipv6) and winxp (ipv4 only).  Needs testing on
newer windows using ipv6 and other unix platforms.

include/uv.h

@@ -1479,6 +1479,10 @@ struct uv_interface_address_s {
     struct sockaddr_in address4;
     struct sockaddr_in6 address6;
   } address;
+  union {
+    struct sockaddr_in netmask4;
+    struct sockaddr_in6 netmask6;
+  } netmask;
 };
 
 UV_EXTERN char** uv_setup_args(int argc, char** argv);

src/unix/aix.c

@@ -369,6 +369,8 @@ uv_err_t uv_interface_addresses(uv_interface_address_t** addresses,
       address->address.address4 = *((struct sockaddr_in *)&p->ifr_addr);
     }
 
+    /* TODO: Retrieve netmask using SIOCGIFNETMASK ioctl */
+
     address->is_internal = flg.ifr_flags & IFF_LOOPBACK ? 1 : 0;
 
     address++;

src/unix/darwin.c

@@ -408,6 +408,12 @@ uv_err_t uv_interface_addresses(uv_interface_address_t** addresses,
       address->address.address4 = *((struct sockaddr_in *)ent->ifa_addr);
     }
 
+    if (ent->ifa_netmask->sa_family == AF_INET6) {
+      address->netmask.netmask6 = *((struct sockaddr_in6 *)ent->ifa_netmask);
+    } else {
+      address->netmask.netmask4 = *((struct sockaddr_in *)ent->ifa_netmask);
+    }
+
     address->is_internal = ent->ifa_flags & IFF_LOOPBACK ? 1 : 0;
 
     address++;

src/unix/linux-core.c

@@ -693,6 +693,12 @@ uv_err_t uv_interface_addresses(uv_interface_address_t** addresses,
       address->address.address4 = *((struct sockaddr_in *)ent->ifa_addr);
     }
 
+    if (ent->ifa_netmask->sa_family == AF_INET6) {
+      address->netmask.netmask6 = *((struct sockaddr_in6 *)ent->ifa_netmask);
+    } else {
+      address->netmask.netmask4 = *((struct sockaddr_in *)ent->ifa_netmask);
+    }
+
     address->is_internal = ent->ifa_flags & IFF_LOOPBACK ? 1 : 0;
 
     address++;

src/unix/netbsd.c

@@ -331,6 +331,12 @@ uv_err_t uv_interface_addresses(uv_interface_address_t** addresses, int* count)
       address->address.address4 = *((struct sockaddr_in *)ent->ifa_addr);
     }
 
+    if (ent->ifa_netmask->sa_family == AF_INET6) {
+      address->netmask.netmask6 = *((struct sockaddr_in6 *)ent->ifa_netmask);
+    } else {
+      address->netmask.netmask4 = *((struct sockaddr_in *)ent->ifa_netmask);
+    }
+
     address->is_internal = !!(ent->ifa_flags & IFF_LOOPBACK) ? 1 : 0;
 
     address++;

src/unix/sunos.c

@@ -622,6 +622,12 @@ uv_err_t uv_interface_addresses(uv_interface_address_t** addresses,
       address->address.address4 = *((struct sockaddr_in *)ent->ifa_addr);
     }
 
+    if (ent->ifa_netmask->sa_family == AF_INET6) {
+      address->netmask.netmask6 = *((struct sockaddr_in6 *)ent->ifa_netmask);
+    } else {
+      address->netmask.netmask4 = *((struct sockaddr_in *)ent->ifa_netmask);
+    }
+
     address->is_internal = ent->ifa_flags & IFF_PRIVATE || ent->ifa_flags &
 	IFF_LOOPBACK ? 1 : 0;
 

src/win/util.c

@@ -31,6 +31,7 @@
 #include "uv.h"
 #include "internal.h"
 
+#include <Winsock2.h>
 #include <iphlpapi.h>
 #include <psapi.h>
 #include <tlhelp32.h>
@@ -765,7 +766,7 @@ uv_err_t uv_interface_addresses(uv_interface_address_t** addresses_ptr,
     /* ERROR_BUFFER_OVERFLOW, and the required buffer size will be stored in */
     /* win_address_buf_size. */
     r = GetAdaptersAddresses(AF_UNSPEC,
-                             0,
+                             GAA_FLAG_INCLUDE_PREFIX,
                              NULL,
                              win_address_buf,
                              &win_address_buf_size);
@@ -882,6 +883,7 @@ uv_err_t uv_interface_addresses(uv_interface_address_t** addresses_ptr,
        win_address != NULL;
        win_address = win_address->Next) {
     IP_ADAPTER_UNICAST_ADDRESS_XP* unicast_address;
+    IP_ADAPTER_PREFIX* prefix;
     int name_size;
     size_t max_name_size;
 
@@ -907,21 +909,55 @@ uv_err_t uv_interface_addresses(uv_interface_address_t** addresses_ptr,
       return uv__new_sys_error(GetLastError());
     }
 
+    prefix = win_address->FirstPrefix;
+
     /* Add an uv_interface_address_t element for every unicast address. */
     for (unicast_address = (IP_ADAPTER_UNICAST_ADDRESS_XP*)
                            win_address->FirstUnicastAddress;
          unicast_address != NULL;
          unicast_address = unicast_address->Next) {
       struct sockaddr* sa;
+      int prefixlen;
 
       uv_address->name = name_buf;
 
+      /* Walk the prefix list in sync with the address list and extract
+         the prefixlen for each address.  On Vista and newer, we could
+         instead just use: unicast_address->OnLinkPrefixLength */
+      if (prefix != NULL) {
+        prefixlen = prefix->PrefixLength;
+        prefix = prefix->Next;
+      } else {
+        prefixlen = 0;
+      }
+
       sa = unicast_address->Address.lpSockaddr;
-      if (sa->sa_family == AF_INET6)
+      if (sa->sa_family == AF_INET6) {
+        int i;
+
         uv_address->address.address6 = *((struct sockaddr_in6 *) sa);
-      else
+
+        uv_address->netmask.netmask6.sin6_family = AF_INET6;
+        prefixlen = prefixlen > 0 ? prefixlen : 128;
+        for (i = 0; i < 16; ++i) {
+          int bits;
+          uint8_t byte_val;
+
+          bits = prefixlen < 8 ? prefixlen : 8;
+          byte_val = ~(0xff >> bits);
+          prefixlen -= bits;
+
+          uv_address->netmask.netmask6.sin6_addr.s6_addr[i] = byte_val;
+        }
+      } else {
         uv_address->address.address4 = *((struct sockaddr_in *) sa);
 
+        uv_address->netmask.netmask4.sin_family = AF_INET;
+        prefixlen = prefixlen > 0 ? prefixlen : 32;
+        uv_address->netmask.netmask4.sin_addr.s_addr =
+          htonl(0xffffffff << (32 - prefixlen));
+      }
+
       uv_address->is_internal =
           (win_address->IfType == IF_TYPE_SOFTWARE_LOOPBACK);
 

test/test-platform-output.c

@@ -80,6 +80,14 @@ TEST_IMPL(platform_output) {
     }
 
     printf("  address: %s\n", buffer);
+
+    if (interfaces[i].netmask.netmask4.sin_family == AF_INET) {
+      uv_ip4_name(&interfaces[i].netmask.netmask4, buffer, sizeof(buffer));
+    } else if (interfaces[i].netmask.netmask4.sin_family == AF_INET6) {
+      uv_ip6_name(&interfaces[i].netmask.netmask6, buffer, sizeof(buffer));
+    }
+
+    printf("  netmask: %s\n", buffer);
   }
   uv_free_interface_addresses(interfaces, count);