C++学习_udp协议(socket)的封装

 1 #ifndef UDP_H
 2 #define UDP_H
 3 
 4 #ifdef MYLINUX
 5 
 6 #include <unistd.h>
 7 #include <arpa/inet.h>
 8 #include <sys/types.h> /* See NOTES */
 9 #include <sys/socket.h>
10 
11 #define SOCKET int
12 
13 #else
14 #include <winsock2.h>
15 #endif
16 
17 class myudp
18 {
19 private:
20     SOCKET st;//类的内部成员一般是不暴露在外面的
21 public:
22     myudp();
23     ~myudp();
24 
25 int socket_send(const char * IP,const char *buf, int len);
26 int socket_recv(char *buf, int len, char * srcIP);
27 int socket_bind(short int port);
28 };
29 
30 #endif // UDP_H 

 1 #include <string.h>
 2 #include <stdio.h>
 3 #include "udp.h"
 4 
 5 //#define MYLINUX ---- linux 下 makefile文件定义 -DMYLINUX
 6 
 7 
 8 
 9 
10 
11 int myudp::socket_send(const char * IP,const char *buf, int len)
12 {
13 
14     st = socket(AF_INET, SOCK_DGRAM, 0);
15     //建立一个socket,第一个参数是指定socket要用哪个协议,AF_INET代表要用TCP/IP协议
16     //第二个参数SOCK_DGRAM意思是要用UDP协议
17     //第三个参数一般默认填0
18     struct sockaddr_in addr;
19     memset(&addr, 0, sizeof(addr));//初始化结构addr
20     addr.sin_family = AF_INET;//代表要使用一个TCP/IP的地址
21     addr.sin_port = htons(8080);//host to net short
22     addr.sin_addr.s_addr = inet_addr(IP);
23     //IP地址解析
24     //unsigned long laddr = inet_addr("192.168.6.200");
25     //unsigned char *p = &laddr;
26     //printf("%u, %u, %u, %u\n", *(p), *(p+1), *(p+2), *(p+3));
27 
28     size_t rc = 0;
29 
30     //发送udp数据
31     rc = sendto(st,buf,len,0,(struct sockaddr *)&addr,sizeof(addr));
32 
33     return rc;
34 }
35 
36 int myudp::socket_recv(char *buf, int len, char * srcIP)
37 {
38     struct sockaddr_in sendaddr;//来自发送方的IP地址
39     memset(&sendaddr,0,sizeof(sendaddr));
40 
41 #ifdef MYLINUX
42     socklen_t len;
43 #else
44     int addrlen;
45 #endif
46     addrlen = sizeof(sendaddr);
47 
48 
49     memset(buf,0,len);
50     size_t rc = recvfrom(st,buf,len,0,(struct sockaddr *)&sendaddr,&addrlen);
51     //inet_ntoa(sendaddr.sin_addr);//这个函数是不可重入函数
52     //多线程调用，这个函数会出问题
53     if(srcIP)
54         strcpy(srcIP,inet_ntoa(sendaddr.sin_addr));
55     //printf("%s:\n%s\n", srcIP, buf);
56 return rc;
57 }
58 
59 myudp::myudp()
60 {
61 #ifndef MYLINUX
62     //初始化socket
63     DWORD ver;
64     WSADATA wsaData;
65     ver = MAKEWORD(1,1);//在调用WASStartup要告诉windows，我用什么版本的socket
66     WSAStartup(ver, &wsaData);//windows要求，只要用socket，第一步，必须调用这个函数
67     //初始化完成
68 #endif
69 
70     st = socket(AF_INET,SOCK_DGRAM,0);//定义一个socket
71 
72 }
73 
74 
75 myudp::~myudp()
76 {
77 #ifdef MYLINUX
78     close(st);
79 #else
80     closesocket(st);//关闭socket
81     WSACleanup();//释放win socket内部的相关资源
82 #endif
83 }
84 
85 
86 int myudp::socket_bind(short port)
87 {
88     struct sockaddr_in addr;
89     memset(&addr,0,sizeof(addr));//初始化addr
90     addr.sin_family = AF_INET;//代表要使用一个TCP/IP的地址
91     addr.sin_port = htons(port);
92     addr.sin_addr.s_addr = htonl(INADDR_ANY);//作为接收方，不需要指定具体的IP地址，接受的主机是什么IP，我就在什么IP接受数据
93     //addr.sin_addr.s_addr = inet_addr("192.168.2.100");
94 
95     return bind(st, (struct sockaddr *)&addr, sizeof(addr)); //将端口号和程序绑定
96 } 

 1 #include <iostream>
 2 #include "udp.h"
 3 
 4 using namespace std;
 5 
 6 int main(int argc, char *args[])
 7 {
 8     if(argc > 1)
 9     {
10         myudp udp;
11         char buf[1024] = {0};
12         while(1)
13         {
14             memset(buf, 0, sizeof(buf));
15             gets(buf);
16             udp.socket_send(args[1],buf, strlen(buf));
17             if (strcmp(buf, "exit") == 0)
18                 break;
19         }
20 
21     }else
22     {
23         myudp udp;
24         char buf[1024] = {0};
25         if(udp.socket_bind(8080) > -1)
26         {
27             char ip[100] = {0};
28             while(1)
29             {
30                 memset(buf, 0, sizeof(buf));
31                 memset(ip, 0, sizeof(ip));
32                 udp.socket_recv(buf,sizeof(buf), ip);
33                 if (strncmp(buf, "exit", 4) == 0)
34                         break;
35                 cout << ip << endl;
36                 cout << buf << endl;
37             }
38         }
39     }
40 
41     cout << "over" << endl;
42     return 0;
43 }