Always use recvmmsg or recvmsg if it's available, and consolidate ReadAndDispatchPackets and ReadAn…

net/tools/quic/quic_packet_reader.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A class to read incoming QUIC packets from the UDP socket.
 
 #ifndef NET_TOOLS_QUIC_QUIC_PACKET_READER_H_
 #define NET_TOOLS_QUIC_QUIC_PACKET_READER_H_
 
 #include <netinet/in.h>
@@ skipping 30 matching lines @@
   // Reads a number of packets from the given fd, and then passes them off to
   // the PacketProcessInterface.  Returns true if there may be additional
   // packets available on the socket.
   // Populates |packets_dropped| if it is non-null and the socket is configured
   // to track dropped packets and some packets are read.
   virtual bool ReadAndDispatchPackets(int fd,
                                       int port,
                                       ProcessPacketInterface* processor,
                                       QuicPacketCount* packets_dropped);
 
-  // Same as ReadAndDispatchPackets, only does one packet at a time.
+ private:
+  // Initialize the internal state of the reader.
+  void Initialize();
+
+  // Reads and dispatches many packets using recvmmsg.
+  bool ReadAndDispatchManyPackets(int fd,
+                                  int port,
+                                  ProcessPacketInterface* processor,
+                                  QuicPacketCount* packets_dropped);
+
+  // Reads and dispatches a single packet using recvmsg.
   static bool ReadAndDispatchSinglePacket(int fd,
                                           int port,
                                           ProcessPacketInterface* processor,
                                           QuicPacketCount* packets_dropped);
 
- private:
-  // Initialize the internal state of the reader.
-  void Initialize();
-
   // Storage only used when recvmmsg is available.
 
 #if MMSG_MORE
   // TODO(danzh): change it to be a pointer to avoid the allocation on the stack
   // from exceeding maximum allowed frame size.
   // packets_ and mmsg_hdr_ are used to supply cbuf and buf to the recvmmsg
   // call.
 
   struct PacketData {
     iovec iov;
     // raw_address is used for address information provided by the recvmmsg
     // call on the packets.
     struct sockaddr_storage raw_address;
     // cbuf is used for ancillary data from the kernel on recvmmsg.
     char cbuf[kSpaceForOverflowAndIp];
     // buf is used for the data read from the kernel on recvmmsg.
     char buf[kMaxPacketSize];
   };
   PacketData packets_[kNumPacketsPerReadMmsgCall];
   mmsghdr mmsg_hdr_[kNumPacketsPerReadMmsgCall];
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(QuicPacketReader);
 };
 
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_QUIC_PACKET_READER_H_