31muduo_net库源码分析（七）

1.Socket封装

（1）Endian.h

 封装了字节序转换函数（全局函数，位于muduo::net::sockets名称空间中）。

（2）SocketsOps.h/ SocketsOps.cc

 封装了socket相关系统调用（全局函数，位于muduo::net::sockets名称空间中）。

（3）Socket.h/Socket.cc（Socket类）

 用RAII方法封装socket file descriptor

（4）InetAddress.h/InetAddress.cc（InetAddress类）

 网际地址sockaddr_in封装

2.代码

1.SocketsOps.h

// Copyright 2010, Shuo Chen.  All rights reserved.// http://code.google.com/p/muduo///// Use of this source code is governed by a BSD-style license// that can be found in the License file.// Author: Shuo Chen (chenshuo at chenshuo dot com)//// This is an internal header file, you should not include this.#ifndef MUDUO_NET_SOCKETSOPS_H#define MUDUO_NET_SOCKETSOPS_H#include <arpa/inet.h>namespace muduo{namespace net{namespace sockets{////// Creates a non-blocking socket file descriptor,/// abort if any error.int createNonblockingOrDie();int  connect(int sockfd, const struct sockaddr_in& addr);void bindOrDie(int sockfd, const struct sockaddr_in& addr);void listenOrDie(int sockfd);int  accept(int sockfd, struct sockaddr_in* addr);ssize_t read(int sockfd, void *buf, size_t count);ssize_t readv(int sockfd, const struct iovec *iov, int iovcnt);ssize_t write(int sockfd, const void *buf, size_t count);void close(int sockfd);void shutdownWrite(int sockfd);void toIpPort(char* buf, size_t size,              const struct sockaddr_in& addr);void toIp(char* buf, size_t size,          const struct sockaddr_in& addr);void fromIpPort(const char* ip, uint16_t port,                  struct sockaddr_in* addr);int getSocketError(int sockfd);struct sockaddr_in getLocalAddr(int sockfd);struct sockaddr_in getPeerAddr(int sockfd);bool isSelfConnect(int sockfd);}}}#endif  // MUDUO_NET_SOCKETSOPS_H

2.SocketsOps.cc

// Copyright 2010, Shuo Chen.  All rights reserved.// http://code.google.com/p/muduo///// Use of this source code is governed by a BSD-style license// that can be found in the License file.// Author: Shuo Chen (chenshuo at chenshuo dot com)#include <muduo/net/SocketsOps.h>#include <muduo/base/Logging.h>#include <muduo/base/Types.h>#include <muduo/net/Endian.h>#include <errno.h>#include <fcntl.h>#include <stdio.h>  // snprintf#include <strings.h>  // bzero#include <sys/socket.h>#include <unistd.h>using namespace muduo;using namespace muduo::net;namespace{typedef struct sockaddr SA;const SA* sockaddr_cast(const struct sockaddr_in* addr){  return static_cast<const SA*>(implicit_cast<const void*>(addr));}SA* sockaddr_cast(struct sockaddr_in* addr){  return static_cast<SA*>(implicit_cast<void*>(addr));}void setNonBlockAndCloseOnExec(int sockfd){  // non-block  int flags = ::fcntl(sockfd, F_GETFL, 0);  flags |= O_NONBLOCK;  int ret = ::fcntl(sockfd, F_SETFL, flags);  // FIXME check  // close-on-exec  flags = ::fcntl(sockfd, F_GETFD, 0);  flags |= FD_CLOEXEC;  ret = ::fcntl(sockfd, F_SETFD, flags);  // FIXME check  (void)ret;}}int sockets::createNonblockingOrDie(){  // socket#if VALGRIND  int sockfd = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);  if (sockfd < 0)  {    LOG_SYSFATAL << "sockets::createNonblockingOrDie";  }  setNonBlockAndCloseOnExec(sockfd);#else  // Linux 2.6.27以上的内核支持SOCK_NONBLOCK与SOCK_CLOEXEC  int sockfd = ::socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, IPPROTO_TCP);  if (sockfd < 0)  {    LOG_SYSFATAL << "sockets::createNonblockingOrDie";  }#endif  return sockfd;}void sockets::bindOrDie(int sockfd, const struct sockaddr_in& addr){  int ret = ::bind(sockfd, sockaddr_cast(&addr), sizeof addr);  if (ret < 0)  {    LOG_SYSFATAL << "sockets::bindOrDie";  }}void sockets::listenOrDie(int sockfd){  int ret = ::listen(sockfd, SOMAXCONN);  if (ret < 0)  {    LOG_SYSFATAL << "sockets::listenOrDie";  }}int sockets::accept(int sockfd, struct sockaddr_in* addr){  socklen_t addrlen = sizeof *addr;#if VALGRIND  int connfd = ::accept(sockfd, sockaddr_cast(addr), &addrlen);  setNonBlockAndCloseOnExec(connfd);#else  int connfd = ::accept4(sockfd, sockaddr_cast(addr),                         &addrlen, SOCK_NONBLOCK | SOCK_CLOEXEC);#endif  if (connfd < 0)  {    int savedErrno = errno;    LOG_SYSERR << "Socket::accept";    switch (savedErrno)    {      case EAGAIN:      case ECONNABORTED:      case EINTR:      case EPROTO: // ???      case EPERM:      case EMFILE: // per-process lmit of open file desctiptor ???        // expected errors        errno = savedErrno;        break;      case EBADF:      case EFAULT:      case EINVAL:      case ENFILE:      case ENOBUFS:      case ENOMEM:      case ENOTSOCK:      case EOPNOTSUPP:        // unexpected errors        LOG_FATAL << "unexpected error of ::accept " << savedErrno;        break;      default:        LOG_FATAL << "unknown error of ::accept " << savedErrno;        break;    }  }  return connfd;}int sockets::connect(int sockfd, const struct sockaddr_in& addr){  return ::connect(sockfd, sockaddr_cast(&addr), sizeof addr);}ssize_t sockets::read(int sockfd, void *buf, size_t count){  return ::read(sockfd, buf, count);}// readv与read不同之处在于，接收的数据可以填充到多个缓冲区中ssize_t sockets::readv(int sockfd, const struct iovec *iov, int iovcnt){  return ::readv(sockfd, iov, iovcnt);}ssize_t sockets::write(int sockfd, const void *buf, size_t count){  return ::write(sockfd, buf, count);}void sockets::close(int sockfd){  if (::close(sockfd) < 0)  {    LOG_SYSERR << "sockets::close";  }}// 只关闭写的这一半void sockets::shutdownWrite(int sockfd){  if (::shutdown(sockfd, SHUT_WR) < 0)  {    LOG_SYSERR << "sockets::shutdownWrite";  }}void sockets::toIpPort(char* buf, size_t size,                       const struct sockaddr_in& addr){  char host[INET_ADDRSTRLEN] = "INVALID";  toIp(host, sizeof host, addr);  uint16_t port = sockets::networkToHost16(addr.sin_port);  snprintf(buf, size, "%s:%u", host, port);}void sockets::toIp(char* buf, size_t size,                   const struct sockaddr_in& addr){  assert(size >= INET_ADDRSTRLEN);  ::inet_ntop(AF_INET, &addr.sin_addr, buf, static_cast<socklen_t>(size));}void sockets::fromIpPort(const char* ip, uint16_t port,                           struct sockaddr_in* addr){  addr->sin_family = AF_INET;  addr->sin_port = hostToNetwork16(port);  if (::inet_pton(AF_INET, ip, &addr->sin_addr) <= 0)  {    LOG_SYSERR << "sockets::fromIpPort";  }}int sockets::getSocketError(int sockfd){  int optval;  socklen_t optlen = sizeof optval;  if (::getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, &optlen) < 0)  {    return errno;  }  else  {    return optval;  }}struct sockaddr_in sockets::getLocalAddr(int sockfd){  struct sockaddr_in localaddr;  bzero(&localaddr, sizeof localaddr);  socklen_t addrlen = sizeof(localaddr);  if (::getsockname(sockfd, sockaddr_cast(&localaddr), &addrlen) < 0)  {    LOG_SYSERR << "sockets::getLocalAddr";  }  return localaddr;}struct sockaddr_in sockets::getPeerAddr(int sockfd){  struct sockaddr_in peeraddr;  bzero(&peeraddr, sizeof peeraddr);  socklen_t addrlen = sizeof(peeraddr);  if (::getpeername(sockfd, sockaddr_cast(&peeraddr), &addrlen) < 0)  {    LOG_SYSERR << "sockets::getPeerAddr";  }  return peeraddr;}// 自连接是指(sourceIP, sourcePort) = (destIP, destPort)// 自连接发生的原因:// 客户端在发起connect的时候，没有bind(2)// 客户端与服务器端在同一台机器，即sourceIP = destIP，// 服务器尚未开启，即服务器还没有在destPort端口上处于监听// 就有可能出现自连接，这样，服务器也无法启动了bool sockets::isSelfConnect(int sockfd){  struct sockaddr_in localaddr = getLocalAddr(sockfd);  struct sockaddr_in peeraddr = getPeerAddr(sockfd);  return localaddr.sin_port == peeraddr.sin_port      && localaddr.sin_addr.s_addr == peeraddr.sin_addr.s_addr;}

3.Socket.h

// Copyright 2010, Shuo Chen.  All rights reserved.// http://code.google.com/p/muduo///// Use of this source code is governed by a BSD-style license// that can be found in the License file.// Author: Shuo Chen (chenshuo at chenshuo dot com)//// This is an internal header file, you should not include this.#ifndef MUDUO_NET_SOCKET_H#define MUDUO_NET_SOCKET_H#include <boost/noncopyable.hpp>namespace muduo{////// TCP networking.///namespace net{class InetAddress;////// Wrapper of socket file descriptor.////// It closes the sockfd when desctructs./// It's thread safe, all operations are delagated to OS.class Socket : boost::noncopyable{ public:  explicit Socket(int sockfd)    : sockfd_(sockfd)  { }  // Socket(Socket&&) // move constructor in C++11  ~Socket();  int fd() const { return sockfd_; }  /// abort if address in use  void bindAddress(const InetAddress& localaddr);  /// abort if address in use  void listen();  /// On success, returns a non-negative integer that is  /// a descriptor for the accepted socket, which has been  /// set to non-blocking and close-on-exec. *peeraddr is assigned.  /// On error, -1 is returned, and *peeraddr is untouched.  int accept(InetAddress* peeraddr);  void shutdownWrite();  ///  /// Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).  ///  // Nagle算法可以一定程度上避免网络拥塞  // TCP_NODELAY选项可以禁用Nagle算法  // 禁用Nagle算法，可以避免连续发包出现延迟，这对于编写低延迟的网络服务很重要  void setTcpNoDelay(bool on);  ///  /// Enable/disable SO_REUSEADDR  ///  void setReuseAddr(bool on);  ///  /// Enable/disable SO_KEEPALIVE  ///  // TCP keepalive是指定期探测连接是否存在，如果应用层有心跳的话，这个选项不是必需要设置的  void setKeepAlive(bool on); private:  const int sockfd_;};}}#endif  // MUDUO_NET_SOCKET_H

4.Socket.cc

// Copyright 2010, Shuo Chen.  All rights reserved.// http://code.google.com/p/muduo///// Use of this source code is governed by a BSD-style license// that can be found in the License file.// Author: Shuo Chen (chenshuo at chenshuo dot com)#include <muduo/net/Socket.h>#include <muduo/net/InetAddress.h>#include <muduo/net/SocketsOps.h>#include <netinet/in.h>#include <netinet/tcp.h>#include <strings.h>  // bzerousing namespace muduo;using namespace muduo::net;Socket::~Socket(){  sockets::close(sockfd_);}void Socket::bindAddress(const InetAddress& addr){  sockets::bindOrDie(sockfd_, addr.getSockAddrInet());}void Socket::listen(){  sockets::listenOrDie(sockfd_);}int Socket::accept(InetAddress* peeraddr){  struct sockaddr_in addr;  bzero(&addr, sizeof addr);  int connfd = sockets::accept(sockfd_, &addr);  if (connfd >= 0)  {    peeraddr->setSockAddrInet(addr);  }  return connfd;}void Socket::shutdownWrite(){  sockets::shutdownWrite(sockfd_);}void Socket::setTcpNoDelay(bool on){  int optval = on ? 1 : 0;  ::setsockopt(sockfd_, IPPROTO_TCP, TCP_NODELAY,               &optval, sizeof optval);  // FIXME CHECK}void Socket::setReuseAddr(bool on){  int optval = on ? 1 : 0;  ::setsockopt(sockfd_, SOL_SOCKET, SO_REUSEADDR,               &optval, sizeof optval);  // FIXME CHECK}void Socket::setKeepAlive(bool on){  int optval = on ? 1 : 0;  ::setsockopt(sockfd_, SOL_SOCKET, SO_KEEPALIVE,               &optval, sizeof optval);  // FIXME CHECK}

5.InetAddress.h

// Copyright 2010, Shuo Chen.  All rights reserved.// http://code.google.com/p/muduo///// Use of this source code is governed by a BSD-style license// that can be found in the License file.// Author: Shuo Chen (chenshuo at chenshuo dot com)//// This is a public header file, it must only include public header files.#ifndef MUDUO_NET_INETADDRESS_H#define MUDUO_NET_INETADDRESS_H#include <muduo/base/copyable.h>#include <muduo/base/StringPiece.h>#include <netinet/in.h>namespace muduo{namespace net{////// Wrapper of sockaddr_in.////// This is an POD interface class.class InetAddress : public muduo::copyable{ public:  /// Constructs an endpoint with given port number.  /// Mostly used in TcpServer listening.  // 仅仅指定port，不指定ip，则ip为INADDR_ANY（即0.0.0.0）  explicit InetAddress(uint16_t port);  /// Constructs an endpoint with given ip and port.  /// @c ip should be "1.2.3.4"  InetAddress(const StringPiece& ip, uint16_t port);  /// Constructs an endpoint with given struct @c sockaddr_in  /// Mostly used when accepting new connections  InetAddress(const struct sockaddr_in& addr)    : addr_(addr)  { }  string toIp() const;  string toIpPort() const;  // __attribute__ ((deprecated)) 表示该函数是过时的，被淘汰的  // 这样使用该函数，在编译的时候，会发出警告  string toHostPort() const __attribute__ ((deprecated))  { return toIpPort(); }  // default copy/assignment are Okay  const struct sockaddr_in& getSockAddrInet() const { return addr_; }  void setSockAddrInet(const struct sockaddr_in& addr) { addr_ = addr; }  uint32_t ipNetEndian() const { return addr_.sin_addr.s_addr; }  uint16_t portNetEndian() const { return addr_.sin_port; } private:  struct sockaddr_in addr_;};}}#endif  // MUDUO_NET_INETADDRESS_H

6.InetAddress.cc

// Copyright 2010, Shuo Chen.  All rights reserved.// http://code.google.com/p/muduo///// Use of this source code is governed by a BSD-style license// that can be found in the License file.// Author: Shuo Chen (chenshuo at chenshuo dot com)#include <muduo/net/InetAddress.h>#include <muduo/net/Endian.h>#include <muduo/net/SocketsOps.h>#include <strings.h>  // bzero#include <netinet/in.h>#include <boost/static_assert.hpp>// INADDR_ANY use (type)value casting.#pragma GCC diagnostic ignored "-Wold-style-cast"static const in_addr_t kInaddrAny = INADDR_ANY;#pragma GCC diagnostic error "-Wold-style-cast"//     /* Structure describing an Internet socket address.  *///     struct sockaddr_in {//         sa_family_t    sin_family; /* address family: AF_INET *///         uint16_t       sin_port;   /* port in network byte order *///         struct in_addr sin_addr;   /* internet address *///     };//     /* Internet address. *///     typedef uint32_t in_addr_t;//     struct in_addr {//         in_addr_t       s_addr;     /* address in network byte order *///     };using namespace muduo;using namespace muduo::net;BOOST_STATIC_ASSERT(sizeof(InetAddress) == sizeof(struct sockaddr_in));InetAddress::InetAddress(uint16_t port){  bzero(&addr_, sizeof addr_);  addr_.sin_family = AF_INET;  addr_.sin_addr.s_addr = sockets::hostToNetwork32(kInaddrAny);  addr_.sin_port = sockets::hostToNetwork16(port);}InetAddress::InetAddress(const StringPiece& ip, uint16_t port){  bzero(&addr_, sizeof addr_);  sockets::fromIpPort(ip.data(), port, &addr_);}string InetAddress::toIpPort() const{  char buf[32];  sockets::toIpPort(buf, sizeof buf, addr_);  return buf;}string InetAddress::toIp() const{  char buf[32];  sockets::toIp(buf, sizeof buf, addr_);  return buf;}

7.InetAddress_unittest.cc

#include <muduo/net/InetAddress.h>//#define BOOST_TEST_MODULE InetAddressTest#define BOOST_TEST_MAIN#define BOOST_TEST_DYN_LINK#include <boost/test/unit_test.hpp>using muduo::string;using muduo::net::InetAddress;BOOST_AUTO_TEST_CASE(testInetAddress){  InetAddress addr1(1234);  BOOST_CHECK_EQUAL(addr1.toIp(), string("0.0.0.0"));  BOOST_CHECK_EQUAL(addr1.toIpPort(), string("0.0.0.0:1234"));  InetAddress addr2("1.2.3.4", 8888);  BOOST_CHECK_EQUAL(addr2.toIp(), string("1.2.3.4"));  BOOST_CHECK_EQUAL(addr2.toIpPort(), string("1.2.3.4:8888"));  InetAddress addr3("255.255.255.255", 65535);  BOOST_CHECK_EQUAL(addr3.toIp(), string("255.255.255.255"));  BOOST_CHECK_EQUAL(addr3.toIpPort(), string("255.255.255.255:65535"));}

8.Endian.h

// Copyright 2010, Shuo Chen.  All rights reserved.// http://code.google.com/p/muduo///// Use of this source code is governed by a BSD-style license// that can be found in the License file.// Author: Shuo Chen (chenshuo at chenshuo dot com)//// This is a public header file, it must only include public header files.#ifndef MUDUO_NET_ENDIAN_H#define MUDUO_NET_ENDIAN_H#include <stdint.h>#include <endian.h>namespace muduo{namespace net{namespace sockets{// the inline assembler code makes type blur,// so we disable warnings for a while.#if __GNUC_MINOR__ >= 6#pragma GCC diagnostic push#endif#pragma GCC diagnostic ignored "-Wconversion"#pragma GCC diagnostic ignored "-Wold-style-cast"inline uint64_t hostToNetwork64(uint64_t host64){  return htobe64(host64);}inline uint32_t hostToNetwork32(uint32_t host32){  return htobe32(host32);}inline uint16_t hostToNetwork16(uint16_t host16){  return htobe16(host16);}inline uint64_t networkToHost64(uint64_t net64){  return be64toh(net64);}inline uint32_t networkToHost32(uint32_t net32){  return be32toh(net32);}inline uint16_t networkToHost16(uint16_t net16){  return be16toh(net16);}#if __GNUC_MINOR__ >= 6#pragma GCC diagnostic pop#else#pragma GCC diagnostic error "-Wconversion"#pragma GCC diagnostic error "-Wold-style-cast"#endif}}}#endif  // MUDUO_NET_ENDIAN_H