Convert IPv6 subnet mask into prefix length

Change-Id: I7921400b3f83876c5d3cb1440fcbf926551cebcb
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>

2 files changed, 84 insertions, 14 deletions

diff --git a/network_manager.cpp b/network_manager.cpp
index 95e1476..e140208 100644
--- a/network_manager.cpp
+++ b/network_manager.cpp
@@ -152,7 +152,6 @@ IntfAddrMap Manager::getInterfaceAddrs() const
             AddrInfo info;
             char ip[INET6_ADDRSTRLEN] = { 0 };
             char subnetMask[INET6_ADDRSTRLEN] = { 0 };
-            uint16_t prefix = { 0 };
 
             if (ifa->ifa_addr->sa_family == AF_INET)
             {
@@ -167,8 +166,6 @@ IntfAddrMap Manager::getInterfaceAddrs() const
                           subnetMask,
                           sizeof(subnetMask));
 
-                prefix = toCidr(subnetMask);
-
             }
             else
             {
@@ -182,13 +179,13 @@ IntfAddrMap Manager::getInterfaceAddrs() const
                           subnetMask,
                           sizeof(subnetMask));
 
-                //TODO: convert v6 mask into cidr
-
             }
 
             info.addrType = ifa->ifa_addr->sa_family;
             info.ipaddress = ip;
-            info.prefix = prefix;
+
+            info.prefix = toCidr(info.addrType, subnetMask);
+
             addrList.emplace_back(info);
         }
     }
@@ -196,16 +193,20 @@ IntfAddrMap Manager::getInterfaceAddrs() const
     return intfMap;
 }
 
-uint8_t Manager::toCidr(const char* subnetMask) const
+uint8_t Manager::toCidr(int addressFamily, const std::string& subnetMask) const
 {
     uint32_t buff = 0;
 
-    auto rc = inet_pton(AF_INET, subnetMask, &buff);
+    if (addressFamily == AF_INET6)
+    {
+        return toV6Cidr(std::string(subnetMask));
+    }
+
+    auto rc = inet_pton(addressFamily, subnetMask.c_str(), &buff);
     if (rc <= 0)
     {
         log<level::ERR>("inet_pton failed:",
-                         entry("Mask=%s", subnetMask));
-        return 0;
+                         entry("SUBNETMASK=%s", subnetMask.c_str()));
     }
 
     buff = be32toh(buff);
@@ -217,9 +218,71 @@ uint8_t Manager::toCidr(const char* subnetMask) const
     else
     {
         log<level::ERR>("Invalid Mask",
-                         entry("Mask=%s", subnetMask));
+                         entry("SUBNETMASK=%s", subnetMask.c_str()));
         return 0;
     }
 }
+
+uint8_t Manager::toV6Cidr(const std::string& subnetMask) const
+{
+    uint8_t pos {};
+    uint8_t prevPos {};
+    uint8_t cidr {};
+    uint16_t buff {};
+
+    log<level::INFO>("toV6Cidr called with",
+                     entry("SUBNETMASK=%s", subnetMask));
+    do
+    {
+        //subnet mask look like ffff:ffff::
+        // or ffff:c000::
+        pos =  subnetMask.find(":", prevPos);
+        if (pos == std::string::npos)
+        {
+            return cidr;
+        }
+
+        auto str = subnetMask.substr(prevPos, (pos - prevPos));
+        prevPos = pos + 1;
+
+        // String length is 0
+        if (!str.length())
+        {
+            return cidr;
+        }
+        //converts it into number.
+        if (sscanf(str.c_str(), "%hx", &buff) <= 0)
+        {
+            log<level::ERR>("Invalid SubnetMask",
+                             entry("SUBNETMASK=%s", subnetMask));
+
+            return 0;
+        }
+
+        // convert the number into bitset
+        // and check for how many ones are there.
+        // if we don't have all the ones then make
+        // sure that all the ones should be left justify.
+
+        if (__builtin_popcount(buff) != 16)
+        {
+            if (((sizeof(buff) * 8) - (__builtin_ctz(buff))) != __builtin_popcount(buff))
+            {
+                log<level::ERR>("Invalid SubnetMask",
+                                 entry("SUBNETMASK=%s", subnetMask));
+
+                return 0;
+            }
+            cidr += __builtin_popcount(buff);
+            return cidr;
+        }
+        cidr += 16;
+
+    }
+    while (1);
+
+    return cidr;
+}
+
 }//namespace network
 }//namespace phosphor
diff --git a/network_manager.hpp b/network_manager.hpp
index fe7debb..d0cb779 100644
--- a/network_manager.hpp
+++ b/network_manager.hpp
@@ -81,10 +81,17 @@ class Manager : public details::VLANCreateIface
         IntfAddrMap getInterfaceAddrs() const;
 
         /** @brief converts the given subnet into prefix notation
-         *  @param[in] subnetMask - Subnet Mask.
-         *  @returns prefix length.
+         *  @param[in] addressFamily - IP address family(AF_INET/AF_INET6)
+         *  @param[in] subnetMask - SubnetMask which needs to be converted.
+         *  @returns prefix.
          */
-        uint8_t toCidr(const char* subnetMask) const;
+        uint8_t toCidr(int addressFamily, const std::string& subnetMask) const;
+
+        /** @brief converts the given V6 subnet into prefix notation
+         *  @param[in] subnetMask - SubnetMask which needs to be converted.
+         *  @returns prefix.
+         */
+        uint8_t toV6Cidr(const std::string& subnetMask) const;
 
         /** @brief Persistent map of EthernetInterface dbus objects and their names */
         std::map<IntfName, std::unique_ptr<EthernetInterface>> interfaces;