Merge pull request #6186

b45c50c Fix two problems in CSubNet parsing (Wladimir J. van der Laan)
19e8d7b Simplify code for CSubnet (Wladimir J. van der Laan)

Author: laanwj

src/netbase.cpp

@@ -1252,15 +1252,15 @@ CSubNet::CSubNet(const std::string &strSubnet, bool fAllowLookup)
             std::string strNetmask = strSubnet.substr(slash + 1);
             int32_t n;
             // IPv4 addresses start at offset 12, and first 12 bytes must match, so just offset n
-            int noffset = network.IsIPv4() ? (12 * 8) : 0;
+            const int astartofs = network.IsIPv4() ? 12 : 0;
             if (ParseInt32(strNetmask, &n)) // If valid number, assume /24 symtex
             {
-                if(n >= 0 && n <= (128 - noffset)) // Only valid if in range of bits of address
+                if(n >= 0 && n <= (128 - astartofs*8)) // Only valid if in range of bits of address
                 {
-                    n += noffset;
+                    n += astartofs*8;
                     // Clear bits [n..127]
                     for (; n < 128; ++n)
-                        netmask[n>>3] &= ~(1<<(n&7));
+                        netmask[n>>3] &= ~(1<<(7-(n&7)));
                 }
                 else
                 {
@@ -1271,12 +1271,10 @@ CSubNet::CSubNet(const std::string &strSubnet, bool fAllowLookup)
             {
                 if (LookupHost(strNetmask.c_str(), vIP, 1, false)) // Never allow lookup for netmask
                 {
-                    // Remember: GetByte returns bytes in reversed order
                     // Copy only the *last* four bytes in case of IPv4, the rest of the mask should stay 1's as
                     // we don't want pchIPv4 to be part of the mask.
-                    int asize = network.IsIPv4() ? 4 : 16;
-                    for(int x=0; x<asize; ++x)
-                        netmask[15-x] = vIP[0].GetByte(x);
+                    for(int x=astartofs; x<16; ++x)
+                        netmask[x] = vIP[0].ip[x];
                 }
                 else
                 {
@@ -1289,14 +1287,18 @@ CSubNet::CSubNet(const std::string &strSubnet, bool fAllowLookup)
     {
         valid = false;
     }
+
+    // Normalize network according to netmask
+    for(int x=0; x<16; ++x)
+        network.ip[x] &= netmask[x];
 }
 
 bool CSubNet::Match(const CNetAddr &addr) const
 {
     if (!valid || !addr.IsValid())
         return false;
     for(int x=0; x<16; ++x)
-        if ((addr.GetByte(x) & netmask[15-x]) != network.GetByte(x))
+        if ((addr.ip[x] & netmask[x]) != network.ip[x])
             return false;
     return true;
 }

src/netbase.h

@@ -100,6 +100,8 @@ class CNetAddr
         inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
             READWRITE(FLATDATA(ip));
         }
+
+        friend class CSubNet;
 };
 
 class CSubNet

src/test/netbase_tests.cpp

@@ -117,6 +117,11 @@ BOOST_AUTO_TEST_CASE(subnet_test)
     BOOST_CHECK(CSubNet("1:2:3:4:5:6:7:8").Match(CNetAddr("1:2:3:4:5:6:7:8")));
     BOOST_CHECK(!CSubNet("1:2:3:4:5:6:7:8").Match(CNetAddr("1:2:3:4:5:6:7:9")));
     BOOST_CHECK(CSubNet("1:2:3:4:5:6:7:0/112").Match(CNetAddr("1:2:3:4:5:6:7:1234")));
+    BOOST_CHECK(CSubNet("192.168.0.1/24").Match(CNetAddr("192.168.0.2")));
+    BOOST_CHECK(CSubNet("192.168.0.20/29").Match(CNetAddr("192.168.0.18")));
+    BOOST_CHECK(CSubNet("1.2.2.1/24").Match(CNetAddr("1.2.2.4")));
+    BOOST_CHECK(CSubNet("1.2.2.110/31").Match(CNetAddr("1.2.2.111")));
+    BOOST_CHECK(CSubNet("1.2.2.20/26").Match(CNetAddr("1.2.2.63")));
     // All-Matching IPv6 Matches arbitrary IPv4 and IPv6
     BOOST_CHECK(CSubNet("::/0").Match(CNetAddr("1:2:3:4:5:6:7:1234")));
     BOOST_CHECK(CSubNet("::/0").Match(CNetAddr("1.2.3.4")));