Fix bug where DNS lookup would fail for very long hostnames.

c++/src/kj/async-io-unix.c++

@@ -732,8 +732,8 @@ public:
       addrTarget = &result.addr.inet4.sin_addr;
     }
 
+    if (addrPart.size() < INET6_ADDRSTRLEN - 1) {
       // addrPart is not necessarily NUL-terminated so we have to make a copy.  :(
-    KJ_REQUIRE(addrPart.size() < INET6_ADDRSTRLEN - 1, "IP address too long.", addrPart);
       char buffer[INET6_ADDRSTRLEN];
       memcpy(buffer, addrPart.begin(), addrPart.size());
       buffer[addrPart.size()] = '\0';
@@ -753,12 +753,15 @@ public:
         }
         case 0:
           // It's apparently not a simple address...  fall back to DNS.
-        return lookupHost(lowLevel, kj::heapString(addrPart), nullptr, port, filter);
+          break;
         default:
           KJ_FAIL_SYSCALL("inet_pton", errno, af, addrPart);
       }
     }
 
+    return lookupHost(lowLevel, kj::heapString(addrPart), nullptr, port, filter);
+  }
+
   static SocketAddress getLocalAddress(int sockfd) {
     SocketAddress result;
     result.addrlen = sizeof(addr);

c++/src/kj/async-io-win32.c++

@@ -634,9 +634,9 @@ public:
       addrTarget = &result.addr.inet4.sin_addr;
     }
 
-    // addrPart is not necessarily NUL-terminated so we have to make a copy.  :(
     char buffer[64];
-    KJ_REQUIRE(addrPart.size() < sizeof(buffer) - 1, "IP address too long.", addrPart);
+    if (addrPart.size() < sizeof(buffer) - 1) {
+      // addrPart is not necessarily NUL-terminated so we have to make a copy.  :(
       memcpy(buffer, addrPart.begin(), addrPart.size());
       buffer[addrPart.size()] = '\0';
 
@@ -655,12 +655,15 @@ public:
         }
         case 0:
           // It's apparently not a simple address...  fall back to DNS.
-        return lookupHost(lowLevel, kj::heapString(addrPart), nullptr, port, filter);
+          break;
         default:
           KJ_FAIL_WIN32("InetPton", WSAGetLastError(), af, addrPart);
       }
     }
 
+    return lookupHost(lowLevel, kj::heapString(addrPart), nullptr, port, filter);
+  }
+
   static SocketAddress getLocalAddress(SOCKET sockfd) {
     SocketAddress result;
     result.addrlen = sizeof(addr);