Fix issue with setting IP address in run time.

Issue: sonic-net/SONiC#22
Issue was observed only when setting IP address via ifconfig
command. Caused by ifconfig command behavior: first is sets
IP address with netmask /8 and then changes netmask to specified
in command. Problem is not observed when set IP address with
"ip addr" command.

orchagent/intfsorch.cpp

@@ -87,33 +87,53 @@ void IntfsOrch::doTask(Consumer &consumer)
             }
 
             auto it_intfs = m_syncdIntfses.find(alias);
-            if (it_intfs == m_syncdIntfses.end() ||
-                !m_syncdIntfses[alias].ip_addresses.contains(ip_prefix.getIp()))
+            if (it_intfs == m_syncdIntfses.end())
             {
-                if (it_intfs == m_syncdIntfses.end())
+                if (addRouterIntfs(port))
                 {
-                    if (addRouterIntfs(port))
-                    {
-                        IntfsEntry intfs_entry;
-                        intfs_entry.ref_count = 0;
-                        m_syncdIntfses[alias] = intfs_entry;
-                    }
-                    else
-                    {
-                        it++;
-                        continue;
-                    }
+                    IntfsEntry intfs_entry;
+                    intfs_entry.ref_count = 0;
+                    m_syncdIntfses[alias] = intfs_entry;
+                }
+                else
+                {
+                    it++;
+                    continue;
                 }
-
-                addSubnetRoute(port, ip_prefix);
-                addIp2MeRoute(ip_prefix);
-
-                m_syncdIntfses[alias].ip_addresses.add(ip_prefix.getIp());
-                it = consumer.m_toSync.erase(it);
             }
-            else
+
+            if (m_syncdIntfses[alias].ip_addresses.count(ip_prefix))
+            {
                 /* Duplicate entry */
                 it = consumer.m_toSync.erase(it);
+                continue;
+            }
+
+            bool overlaps = false;
+            for (const auto &prefixIt: m_syncdIntfses[alias].ip_addresses)
+            {
+                if (prefixIt.isAddressInSubnet(ip_prefix.getIp()) ||
+                        ip_prefix.isAddressInSubnet(prefixIt.getIp()))
+                {
+                    overlaps = true;
+                    SWSS_LOG_NOTICE("Router interface %s IP %s overlaps with %s.", port.m_alias.c_str(),
+                            prefixIt.to_string().c_str(), ip_prefix.to_string().c_str());
+                    break;
+                }
+            }
+
+            if (overlaps)
+            {
+                /* Overlap of IP address network */
+                ++it;
+                continue;
+            }
+
+            addSubnetRoute(port, ip_prefix);
+            addIp2MeRoute(ip_prefix);
+
+            m_syncdIntfses[alias].ip_addresses.insert(ip_prefix);
+            it = consumer.m_toSync.erase(it);
         }
         else if (op == DEL_COMMAND)
         {
@@ -134,16 +154,16 @@ void IntfsOrch::doTask(Consumer &consumer)
 
             if (m_syncdIntfses.find(alias) != m_syncdIntfses.end())
             {
-                if (m_syncdIntfses[alias].ip_addresses.contains(ip_prefix.getIp()))
+                if (m_syncdIntfses[alias].ip_addresses.count(ip_prefix))
                 {
                     removeSubnetRoute(port, ip_prefix);
                     removeIp2MeRoute(ip_prefix);
 
-                    m_syncdIntfses[alias].ip_addresses.remove(ip_prefix.getIp());
+                    m_syncdIntfses[alias].ip_addresses.erase(ip_prefix);
                 }
 
                 /* Remove router interface that no IP addresses are associated with */
-                if (m_syncdIntfses[alias].ip_addresses.getSize() == 0)
+                if (m_syncdIntfses[alias].ip_addresses.size() == 0)
                 {
                     if (removeRouterIntfs(port))
                     {

orchagent/intfsorch.h

@@ -9,13 +9,14 @@
 #include "macaddress.h"
 
 #include <map>
+#include <set>
 
 extern sai_object_id_t gVirtualRouterId;
 extern MacAddress gMacAddress;
 
 struct IntfsEntry
 {
-    IpAddresses         ip_addresses;
+    std::set<IpPrefix>  ip_addresses;
     int                 ref_count;
 };