UDP服务器/客户端代码示例

UDP服务器代码：

 #include <errno.h>
 #include <string.h>
 #include <stdlib.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <iostream>

 using namespace std;

 int main(int argc, char *argv[])
 {
     if (argc != )
     {
         cout << "usage: " << argv[] << " ip port" << endl;
         return -;
     }

     char *szIp = argv[];
     in_addr_t iIp = inet_addr(szIp);
     if (iIp == INADDR_NONE)
     {
         cerr << "fail to parse ip: " << szIp << endl;
         return -;
     }
     char *pEnd = NULL;
     uint16_t usPort = strtoul(argv[], &pEnd, );
     if (*pEnd != '\0')
     {
         cerr << "fail to parse port: " << argv[] << endl;
         return -;
     }

     int iSockFd = socket(AF_INET, SOCK_DGRAM, );
     if (iSockFd < )
     {
         cerr << "fail to create socket, err: " << strerror(errno) << endl;
         return -;
     }
     cout << "create socket fd " << iSockFd << endl;

     sockaddr_in oAddr;
     memset(&oAddr, , sizeof(oAddr));
     oAddr.sin_family = AF_INET;
     oAddr.sin_addr.s_addr = iIp;
     oAddr.sin_port = htons(usPort);
     if (bind(iSockFd, (sockaddr *)&oAddr, sizeof(oAddr)) < )
     {
         cerr << "fail to bind addr " << szIp << ":" << usPort << ", err: " << strerror(errno) << endl;
         return -;
     }
     cout << "bind addr " << szIp << ":" >> usPort << endl;

     uint8_t acRecvBuf[ * ];
     while (true)
     {
         sockaddr_in oClientAddr;
         socklen_t iAddrLen = sizeof(oClientAddr);
         ssize_t iRecvLen = recvfrom(iSockFd, acRecvBuf, sizeof(acRecvBuf), , (sockaddr *)&oClientAddr, &iAddrLen);
         if (iRecvLen < )
         {
             cerr << "fail to recv, err: " << strerror(errno) << endl;
             continue;
         }
         cout << "recv data from " << inet_ntoa(oClientAddr.sin_addr) << ":" << ntohs(oClientAddr.sin_port) << ", len: " << iRecvLen << endl;

         ssize_t iSendLen = sendto(iSockFd, acRecvBuf, iRecvLen, , (sockaddr *)&oClientAddr, iAddrLen);
         if (iSendLen < )
         {
             cerr << "fail to send, err: " << strerror(errno) << endl;
             continue;
         }
         cout << "echo to client, len: " << iSendLen << endl;
     }

     return ;
 }

UDP客户端代码：

 #include <errno.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <stdlib.h>
 #include <iostream>

 using namespace std;

 int main(int argc, char *argv[])
 {
     if (argc != )
     {
         cout << "usage: " << argv[] << " ip port message" << endl;
         return -;
     }

     char *szIp = argv[];
     in_addr_t iIp = inet_addr(szIp);
     if (iIp == INADDR_NONE)
     {
         cerr << "fail to parse ip: " << szIp << endl;
         return -;
     }
     char *pEnd = NULL;
     uint16_t usPort = strtoul(argv[], &pEnd, );
     if (*pEnd != '\0')
     {
         cerr << "fail to parse port: " << argv[] << endl;
         return -;
     }
     char *szMsg = argv[];
     size_t uiMsgLen = strlen(szMsg);

     int iSockFd = socket(AF_INET, SOCK_DGRAM, );
     if (iSockFd < )
     {
         cerr << "fail to create socket, err: " << strerror(errno) << endl;
         return -;
     }
     cout << "create socket fd " << iSockFd << endl;

     sockaddr_in oServerAddr;
     memset(&oServerAddr, , sizeof(oServerAddr));
     oServerAddr.sin_family = AF_INET;
     oServerAddr.sin_addr.s_addr = iIp;
     oServerAddr.sin_port = htons(usPort);
     ssize_t iSendLen = sendto(iSockFd, szMsg, uiMsgLen, , (sockaddr *)&oServerAddr, sizeof(oServerAddr));
     if (iSendLen < )
     {
         cerr << "fail to send, err: " << strerror(errno) << endl;
         return -;
     }
     cout << "send to " << szIp <<  ":" << usPort << ", len: " << uiMsgLen << ", msg: " << szMsg << endl;

     char szRecvBuf[ * ];
     sockaddr_in oRecvAddr;
     socklen_t iAddrLen = sizeof(oRecvAddr);
     ssize_t iRecvLen = recvfrom(iSockFd, szRecvBuf, sizeof(szRecvBuf), , (sockaddr *)&oRecvAddr, &iAddrLen);
     if (iRecvLen < )
     {
         cerr << "fail to recv, err: " << strerror(errno) << endl;
         return -;
     }
     szRecvBuf[iRecvLen] = '\0';
     cout << "recv from " << inet_ntoa(oRecvAddr.sin_addr) << ":" << ntohs(oRecvAddr.sin_port) << ", len: " << iRecvLen << ", msg: " << szRecvBuf << endl; 

     return ;
 }