求助：反弹端口程序代码．100分相送

就是反向连接了.服务器端用connect就可以了.
还有一个端口复用技术,是用setsockopt函数.
网上完整的源代码是很难找的.

也发给我一份
[email protected]
谢谢！

下面是一个模拟P2P聊天的过程的源代码，过程很简单，P2PServer运行在一个拥有公网IP的计算机上，P2PClient运行在两个不同的NAT后（注意，如果两个客户端运行在一个NAT后，本程序很可能不能运行正常，这取决于你的NAT是否支持loopback translation，详见http://midcom-p2p.sourceforge.net/draft-ford-midcom-p2p-01.txt，当然，此问题可以通过双方先尝试连接对方的内网IP来解决，但是这个代码只是为了验证原理，并没有处理这些问题），后登录的计算机可以获得先登录计算机的用户名，后登录的计算机通过send username message的格式来发送消息。如果发送成功，说明你已取得了直接与对方连接的成功。
    程序现在支持三个命令：send , getu , exit

    send格式：send username message
    功能：发送信息给username

    getu格式：getu
    功能：获得当前服务器用户列表

    exit格式：exit
    功能：注销与服务器的连接（服务器不会自动监测客户是否吊线）

    代码很短，相信很容易懂，如果有什么问题，可以给我发邮件[email protected]  或者在CSDN上发送短消息。同时，欢迎转发此文，但希望保留作者版权8-）。

    最后感谢CSDN网友 PiggyXP 和 Seilfer的测试帮助P2PServer.c/* P2P 程序服务端
*
* 文件名：P2PServer.c
*
* 日期：2004-5-21
*
* 作者：shootingstars([email protected])
*
*/
#pragma comment(lib, "ws2_32.lib")#include "windows.h"
#include "..\proto.h"
#include "..\Exception.h"UserList ClientList;void InitWinSock()
{
WSADATA wsaData;if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
{
  printf("Windows sockets 2.2 startup");
  throw Exception("");
}
else{
  printf("Using %s (Status: %s)\n",
   wsaData.szDescription, wsaData.szSystemStatus);
  printf("with API versions %d.%d to %d.%d\n\n",
   LOBYTE(wsaData.wVersion), HIBYTE(wsaData.wVersion),
   LOBYTE(wsaData.wHighVersion), HIBYTE(wsaData.wHighVersion));

}
}SOCKET mksock(int type)
{
SOCKET sock = socket(AF_INET, type, 0);
if (sock < 0)
{
        printf("create socket error");
  throw Exception("");
}
return sock;
}stUserListNode GetUser(char *username)
{
for(UserList::iterator UserIterator=ClientList.begin();
      UserIterator!=ClientList.end();
       ++UserIterator)
{
  if( strcmp( ((*UserIterator)->userName), username) == 0 )
   return *(*UserIterator);
}
throw Exception("not find this user");
}int main(int argc, char* argv[])
{
try{
  InitWinSock();

  SOCKET PrimaryUDP;
  PrimaryUDP = mksock(SOCK_DGRAM);  sockaddr_in local;
  local.sin_family=AF_INET;
  local.sin_port= htons(SERVER_PORT);
  local.sin_addr.s_addr = htonl(INADDR_ANY);
  int nResult=bind(PrimaryUDP,(sockaddr*)&local,sizeof(sockaddr));
  if(nResult==SOCKET_ERROR)
   throw Exception("bind error");  sockaddr_in sender;
  stMessage recvbuf;
  memset(&recvbuf,0,sizeof(stMessage));  // 开始主循环.
  // 主循环负责下面几件事情:
  // 一:读取客户端登陆和登出消息,记录客户列表
  // 二:转发客户p2p请求
  for(;;)
  {
   int dwSender = sizeof(sender);
   int ret = recvfrom(PrimaryUDP, (char *)&recvbuf, sizeof(stMessage), 0, (sockaddr *)&sender, &dwSender);
   if(ret <= 0)
   {
    printf("recv error");
    continue;
   }
   else
   {
    int messageType = recvbuf.iMessageType;
    switch(messageType){
    case LOGIN:
     {
      //  将这个用户的信息记录到用户列表中
      printf("has a user login : %s\n", recvbuf.message.loginmember.userName);
      stUserListNode *currentuser = new stUserListNode();
      strcpy(currentuser->userName, recvbuf.message.loginmember.userName);
      currentuser->ip = ntohl(sender.sin_addr.S_un.S_addr);
      currentuser->port = ntohs(sender.sin_port);

      ClientList.push_back(currentuser);      // 发送已经登陆的客户信息
      int nodecount = (int)ClientList.size();
      sendto(PrimaryUDP, (const char*)&nodecount, sizeof(int), 0, (const sockaddr*)&sender, sizeof(sender));
      for(UserList::iterator UserIterator=ClientList.begin();
        UserIterator!=ClientList.end();
        ++UserIterator)
      {
       sendto(PrimaryUDP, (const char*)(*UserIterator), sizeof(stUserListNode), 0, (const sockaddr*)&sender, sizeof(sender));
      }      break;
     }
    case LOGOUT:
     {
      // 将此客户信息删除
      printf("has a user logout : %s\n", recvbuf.message.logoutmember.userName);
      UserList::iterator removeiterator = NULL;
      for(UserList::iterator UserIterator=ClientList.begin();
       UserIterator!=ClientList.end();
       ++UserIterator)
      {
       if( strcmp( ((*UserIterator)->userName), recvbuf.message.logoutmember.userName) == 0 )
       {
        removeiterator = UserIterator;
        break;
       }
      }
      if(removeiterator != NULL)
       ClientList.remove(*removeiterator);
      break;
     }
    case P2PTRANS:
     {
      // 某个客户希望服务端向另外一个客户发送一个打洞消息
      printf("%s wants to p2p %s\n",inet_ntoa(sender.sin_addr),recvbuf.message.translatemessage.userName);
      stUserListNode node = GetUser(recvbuf.message.translatemessage.userName);
      sockaddr_in remote;
      remote.sin_family=AF_INET;
      remote.sin_port= htons(node.port);
      remote.sin_addr.s_addr = htonl(node.ip);      in_addr tmp;
      tmp.S_un.S_addr = htonl(node.ip);
      printf("the address is %s,and port is %d\n",inet_ntoa(tmp), node.port);      stP2PMessage transMessage;
      transMessage.iMessageType = P2PSOMEONEWANTTOCALLYOU;
      transMessage.iStringLen = ntohl(sender.sin_addr.S_un.S_addr);
      transMessage.Port = ntohs(sender.sin_port);

      sendto(PrimaryUDP,(const char*)&transMessage, sizeof(transMessage), 0, (const sockaddr *)&remote, sizeof(remote));      break;
     }

    case GETALLUSER:
     {
      int command = GETALLUSER;
      sendto(PrimaryUDP, (const char*)&command, sizeof(int), 0, (const sockaddr*)&sender, sizeof(sender));      int nodecount = (int)ClientList.size();
      sendto(PrimaryUDP, (const char*)&nodecount, sizeof(int), 0, (const sockaddr*)&sender, sizeof(sender));      for(UserList::iterator UserIterator=ClientList.begin();
        UserIterator!=ClientList.end();
        ++UserIterator)
      {
       sendto(PrimaryUDP, (const char*)(*UserIterator), sizeof(stUserListNode), 0, (const sockaddr*)&sender, sizeof(sender));
      }
      break;
     }
    }
   }
  }}
catch(Exception &e)
{
  printf(e.GetMessage());
  return 1;
}return 0;
}

void BindSock(SOCKET sock)
{
sockaddr_in sin;
sin.sin_addr.S_un.S_addr = INADDR_ANY;
sin.sin_family = AF_INET;
sin.sin_port = 0;if (bind(sock, (struct sockaddr*)&sin, sizeof(sin)) < 0)
  throw Exception("bind error");
}void ConnectToServer(SOCKET sock,char *username, char *serverip)
{
sockaddr_in remote;
remote.sin_addr.S_un.S_addr = inet_addr(serverip);
remote.sin_family = AF_INET;
remote.sin_port = htons(SERVER_PORT);stMessage sendbuf;
sendbuf.iMessageType = LOGIN;
strncpy(sendbuf.message.loginmember.userName, username, 10);sendto(sock, (const char*)&sendbuf, sizeof(sendbuf), 0, (const sockaddr*)&remote,sizeof(remote));int usercount;
int fromlen = sizeof(remote);
int iread = recvfrom(sock, (char *)&usercount, sizeof(int), 0, (sockaddr *)&remote, &fromlen);
if(iread<=0)
{
  throw Exception("Login error\n");
}// 登录到服务端后，接收服务端发来的已经登录的用户的信息
cout<<"Have "<<usercount<<" users logined server:"<<endl;
for(int i = 0;i<usercount;i++)
{
  stUserListNode *node = new stUserListNode;
  recvfrom(sock, (char*)node, sizeof(stUserListNode), 0, (sockaddr *)&remote, &fromlen);
  ClientList.push_back(node);
  cout<<"Username:"<<node->userName<<endl;
  in_addr tmp;
  tmp.S_un.S_addr = htonl(node->ip);
  cout<<"UserIP:"<<inet_ntoa(tmp)<<endl;
  cout<<"UserPort:"<<node->port<<endl;
  cout<<""<<endl;
}
}void OutputUsage()
{
cout<<"You can input you command:\n"
  <<"Command Type:\"send\",\"exit\",\"getu\"\n"
  <<"Example : send Username Message\n"
  <<"          exit\n"
  <<"          getu\n"
  <<endl;
}/* 这是主要的函数：发送一个消息给某个用户(C)
*流程：直接向某个用户的外网IP发送消息，如果此前没有联系过
*      那么此消息将无法发送，发送端等待超时。
*      超时后，发送端将发送一个请求信息到服务端，
*      要求服务端发送给客户C一个请求，请求C给本机发送打洞消息
*      以上流程将重复MAXRETRY次
*/
bool SendMessageTo(char *UserName, char *Message)
{
char realmessage[256];
unsigned int UserIP;
unsigned short UserPort;
bool FindUser = false;
for(UserList::iterator UserIterator=ClientList.begin();
      UserIterator!=ClientList.end();
      ++UserIterator)
{
  if( strcmp( ((*UserIterator)->userName), UserName) == 0 )
  {
   UserIP = (*UserIterator)->ip;
   UserPort = (*UserIterator)->port;
   FindUser = true;
  }
}if(!FindUser)
  return false;strcpy(realmessage, Message);
for(int i=0;i<MAXRETRY;i++)
{
  RecvedACK = false;  sockaddr_in remote;
  remote.sin_addr.S_un.S_addr = htonl(UserIP);
  remote.sin_family = AF_INET;
  remote.sin_port = htons(UserPort);
  stP2PMessage MessageHead;
  MessageHead.iMessageType = P2PMESSAGE;
  MessageHead.iStringLen = (int)strlen(realmessage)+1;
  int isend = sendto(PrimaryUDP, (const char *)&MessageHead, sizeof(MessageHead), 0, (const sockaddr*)&remote, sizeof(remote));
  isend = sendto(PrimaryUDP, (const char *)&realmessage, MessageHead.iStringLen, 0, (const sockaddr*)&remote, sizeof(remote));

  // 等待接收线程将此标记修改
  for(int j=0;j<10;j++)
  {
   if(RecvedACK)
    return true;
   else
    Sleep(300);
  }  // 没有接收到目标主机的回应，认为目标主机的端口映射没有
  // 打开，那么发送请求信息给服务器，要服务器告诉目标主机
  // 打开映射端口（UDP打洞）
  sockaddr_in server;
  server.sin_addr.S_un.S_addr = inet_addr(ServerIP);
  server.sin_family = AF_INET;
  server.sin_port = htons(SERVER_PORT);  stMessage transMessage;
  transMessage.iMessageType = P2PTRANS;
  strcpy(transMessage.message.translatemessage.userName, UserName);  sendto(PrimaryUDP, (const char*)&transMessage, sizeof(transMessage), 0, (const sockaddr*)&server, sizeof(server));
  Sleep(100);// 等待对方先发送信息。
}
return false;
}
// 解析命令，暂时只有exit和send命令
// 新增getu命令，获取当前服务器的所有用户
void ParseCommand(char * CommandLine)
{
if(strlen(CommandLine)<4)
  return;
char Command[10];
strncpy(Command, CommandLine, 4);
Command[4]='\0';if(strcmp(Command,"exit")==0)
{
  stMessage sendbuf;
  sendbuf.iMessageType = LOGOUT;
  strncpy(sendbuf.message.logoutmember.userName, UserName, 10);
  sockaddr_in server;
  server.sin_addr.S_un.S_addr = inet_addr(ServerIP);
  server.sin_family = AF_INET;
  server.sin_port = htons(SERVER_PORT);  sendto(PrimaryUDP,(const char*)&sendbuf, sizeof(sendbuf), 0, (const sockaddr *)&server, sizeof(server));
  shutdown(PrimaryUDP, 2);
  closesocket(PrimaryUDP);
  exit(0);
}
else if(strcmp(Command,"send")==0)
{
  char sendname[20];
  char message[COMMANDMAXC];
  int i;
  for(i=5;;i++)
  {
   if(CommandLine[i]!=' ')
    sendname[i-5]=CommandLine[i];
   else
   {
    sendname[i-5]='\0';
    break;
   }
  }
  strcpy(message, &(CommandLine[i+1]));
  if(SendMessageTo(sendname, message))
   printf("Send OK!\n");
  else
   printf("Send Failure!\n");
}
else if(strcmp(Command,"getu")==0)
{
  int command = GETALLUSER;
  sockaddr_in server;
  server.sin_addr.S_un.S_addr = inet_addr(ServerIP);
  server.sin_family = AF_INET;
  server.sin_port = htons(SERVER_PORT);  sendto(PrimaryUDP,(const char*)&command, sizeof(command), 0, (const sockaddr *)&server, sizeof(server));
}
}// 接受消息线程
DWORD WINAPI RecvThreadProc(LPVOID lpParameter)
{
sockaddr_in remote;
int sinlen = sizeof(remote);
stP2PMessage recvbuf;
for(;;)
{
  int iread = recvfrom(PrimaryUDP, (char *)&recvbuf, sizeof(recvbuf), 0, (sockaddr *)&remote, &sinlen);
  if(iread<=0)
  {
   printf("recv error\n");
   continue;
  }
  switch(recvbuf.iMessageType)
  {
  case P2PMESSAGE:
   {
    // 接收到P2P的消息
    char *comemessage= new char[recvbuf.iStringLen];
    int iread1 = recvfrom(PrimaryUDP, comemessage, 256, 0, (sockaddr *)&remote, &sinlen);
    comemessage[iread1-1] = '\0';
    if(iread1<=0)
     throw Exception("Recv Message Error\n");
    else
    {
     printf("Recv a Message:%s\n",comemessage);

     stP2PMessage sendbuf;
     sendbuf.iMessageType = P2PMESSAGEACK;
     sendto(PrimaryUDP, (const char*)&sendbuf, sizeof(sendbuf), 0, (const sockaddr*)&remote, sizeof(remote));
    }    delete []comemessage;
    break;   }
  case P2PSOMEONEWANTTOCALLYOU:
   {
    // 接收到打洞命令，向指定的IP地址打洞
    printf("Recv p2someonewanttocallyou data\n");
    sockaddr_in remote;
    remote.sin_addr.S_un.S_addr = htonl(recvbuf.iStringLen);
    remote.sin_family = AF_INET;
    remote.sin_port = htons(recvbuf.Port);    // UDP hole punching
    stP2PMessage message;
    message.iMessageType = P2PTRASH;
    sendto(PrimaryUDP, (const char *)&message, sizeof(message), 0, (const sockaddr*)&remote, sizeof(remote));

    break;
   }
  case P2PMESSAGEACK:
   {
    // 发送消息的应答
    RecvedACK = true;
    break;
   }
  case P2PTRASH:
   {
    // 对方发送的打洞消息，忽略掉。
    //do nothing ...
    printf("Recv p2ptrash data\n");
    break;
   }
  case GETALLUSER:
   {
    int usercount;
    int fromlen = sizeof(remote);
    int iread = recvfrom(PrimaryUDP, (char *)&usercount, sizeof(int), 0, (sockaddr *)&remote, &fromlen);
    if(iread<=0)
    {
     throw Exception("Login error\n");
    }

    ClientList.clear();    cout<<"Have "<<usercount<<" users logined server:"<<endl;
    for(int i = 0;i<usercount;i++)
    {
     stUserListNode *node = new stUserListNode;
     recvfrom(PrimaryUDP, (char*)node, sizeof(stUserListNode), 0, (sockaddr *)&remote, &fromlen);
     ClientList.push_back(node);
     cout<<"Username:"<<node->userName<<endl;
     in_addr tmp;
     tmp.S_un.S_addr = htonl(node->ip);
     cout<<"UserIP:"<<inet_ntoa(tmp)<<endl;
     cout<<"UserPort:"<<node->port<<endl;
     cout<<""<<endl;
    }
    break;
   }
  }
}
}

调试易

求助：反弹端口程序代码．100分相送

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