文章目錄
參考學習網址:http://c.biancheng.net/cpp/socket/
一,網絡編程相關結構體
1.WSAData 結構體
typedef struct WSAData {
WORD wVersion; //ws2_32.dll 建議我們使用的版本號
WORD wHighVersion; //ws2_32.dll 支持的最高版本號
//一個以 null 結尾的字符串,用來說明 ws2_32.dll 的實現以及廠商信息
char szDescription[WSADESCRIPTION_LEN+1];
//一個以 null 結尾的字符串,用來說明 ws2_32.dll 的狀態以及配置信息
char szSystemStatus[WSASYS_STATUS_LEN+1];
unsigned short iMaxSockets; //2.0以後不再使用
unsigned short iMaxUdpDg; //2.0以後不再使用
char FAR *lpVendorInfo; //2.0以後不再使用
} WSADATA, *LPWSADATA;
2.sockaddr_in 結構體
struct sockaddr_in{
sa_family_t sin_family; //地址族(Address Family),也就是地址類型
uint16_t sin_port; //16位的端口號
struct in_addr sin_addr; //32位IP地址
char sin_zero[8]; //不使用,一般用0填充
};
3.in_addr 結構體
struct in_addr{
in_addr_t s_addr; //32位的IP地址
};
4.sockaddr 結構體
struct sockaddr{
sa_family_t sin_family; //地址族(Address Family),也就是地址類型
char sa_data[14]; //IP地址和端口號
};
結構體之間的關係(in_addr—> sockaddr_in —> sockaddr)
sockaddr_in 和in_addr 兩個結構體的關係(將整數轉化爲字符ip):
s_addr 是一個整數,而IP地址是一個字符串,所以需要 inet_addr() 函數進行轉換
eg:
unsigned long ip = inet_addr("127.0.0.1");
printf("%ld\n", ip);
sockaddr 與 sockaddr_in 的對比
二,UDP傳輸
1.基於UDP(回聲服務器端/客戶端)
①
回聲傳輸
動態鏈接庫頭文件引用+初始化
創建套接字
綁定套接字的ip和端口號
監聽
②
發送數據
接受數據
——————————————————————————————————————
服務器端 server.cpp:
#include <stdio.h>
#include <winsock2.h>
#pragma comment (lib, "ws2_32.lib") //加載鏈接庫頭文件 ws2_32.dll
#define BUF_SIZE 100
int main(){
WSADATA wsaData;
WSAStartup( MAKEWORD(2, 2), &wsaData);//初始化WSAData 結構體
//創建套接字
SOCKET servSock = socket(AF_INET, SOCK_STREAM, 0);
//綁定套接字
sockaddr_in sockAddr;
memset(&sockAddr, 0, sizeof(sockAddr)); //每個字節都用0填充
sockAddr.sin_family = PF_INET; //使用IPv4地址
sockAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); //具體的IP地址,整數s_addr 字符串IP地址
sockAddr.sin_port = htons(1234); //端口
bind(servSock, (SOCKADDR*)&sockAddr, sizeof(SOCKADDR));
//進入監聽狀態
listen(servSock, 20);
//接收客戶端請求
SOCKADDR clntAddr;
int nSize = sizeof(SOCKADDR);
SOCKET clntSock = accept(servSock, (SOCKADDR*)&clntAddr, &nSize);
char buffer[BUF_SIZE]; //緩衝區
int strLen = recv(clntSock, buffer, BUF_SIZE, 0); //接收客戶端發來的數據
send(clntSock, buffer, strLen, 0); //將數據原樣返回
//關閉套接字
closesocket(clntSock);
closesocket(servSock);
//終止 DLL 的使用
WSACleanup();
return 0;
}
客戶端 client.cpp:
#include <stdio.h>
#include <stdlib.h>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib") //加載 ws2_32.dll
#define BUF_SIZE 100
int main(){
//初始化DLL
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);
//創建套接字
SOCKET sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
//向服務器發起請求
sockaddr_in sockAddr;
memset(&sockAddr, 0, sizeof(sockAddr)); //每個字節都用0填充
sockAddr.sin_family = PF_INET;
sockAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
sockAddr.sin_port = htons(1234);
connect(sock, (SOCKADDR*)&sockAddr, sizeof(SOCKADDR));
//獲取用戶輸入的字符串併發送給服務器
char bufSend[BUF_SIZE] = {0};
printf("Input a string: ");
scanf("%s", bufSend);
send(sock, bufSend, strlen(bufSend), 0);
//接收服務器傳回的數據
char bufRecv[BUF_SIZE] = {0};
recv(sock, bufRecv, BUF_SIZE, 0);
//輸出接收到的數據
printf("Message form server: %s\n", bufRecv);
//關閉套接字
closesocket(sock);
//終止使用 DLL
WSACleanup();
system("pause");
return 0;
}
2.基於UDP編程(服務器端持續監聽客戶端的請求)
服務器端 server.cpp:
#include <stdio.h>
#include <winsock2.h>
#pragma comment (lib, "ws2_32.lib") //加載 ws2_32.dll
#define BUF_SIZE 100
int main(){
WSADATA wsaData;
WSAStartup( MAKEWORD(2, 2), &wsaData);
//創建套接字
SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);
//綁定套接字
sockaddr_in servAddr;
memset(&servAddr, 0, sizeof(servAddr)); //每個字節都用0填充
servAddr.sin_family = PF_INET; //使用IPv4地址
servAddr.sin_addr.s_addr = htonl(INADDR_ANY); //自動獲取IP地址
servAddr.sin_port = htons(1234); //端口
bind(sock, (SOCKADDR*)&servAddr, sizeof(SOCKADDR));
//接收客戶端請求
SOCKADDR clntAddr; //客戶端地址信息
int nSize = sizeof(SOCKADDR);
char buffer[BUF_SIZE]; //緩衝區
while(1){
int strLen = recvfrom(sock, buffer, BUF_SIZE, 0, &clntAddr, &nSize);
sendto(sock, buffer, strLen, 0, &clntAddr, nSize);
}
closesocket(sock);
WSACleanup();
return 0;
}
客戶端 client.cpp:
#include <stdio.h>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib") //加載 ws2_32.dll
#define BUF_SIZE 100
int main(){
//初始化DLL
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);
//創建套接字
SOCKET sock = socket(PF_INET, SOCK_DGRAM, 0);
//服務器地址信息
sockaddr_in servAddr;
memset(&servAddr, 0, sizeof(servAddr)); //每個字節都用0填充
servAddr.sin_family = PF_INET;
servAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
servAddr.sin_port = htons(1234);
//不斷獲取用戶輸入併發送給服務器,然後接受服務器數據
sockaddr fromAddr;
int addrLen = sizeof(fromAddr);
while(1){
char buffer[BUF_SIZE] = {0};
printf("Input a string: ");
gets(buffer);
sendto(sock, buffer, strlen(buffer), 0, (struct sockaddr*)&servAddr, sizeof(servAddr));
int strLen = recvfrom(sock, buffer, BUF_SIZE, 0, &fromAddr, &addrLen);
buffer[strLen] = 0;
printf("Message form server: %s\n", buffer);
}
closesocket(sock);
WSACleanup();
return 0;
}
三,TCP傳輸
1.TCP實現文件傳輸
服務器端 server.cpp:
#include <stdio.h>
#include <stdlib.h>
#include <winsock2.h>
#pragma comment (lib, "ws2_32.lib") //加載 ws2_32.dll
#define BUF_SIZE 1024
int main(){
//先檢查文件是否存在
char *filename = "D:\\send.avi"; //文件名
FILE *fp = fopen(filename, "rb"); //以二進制方式打開文件
if(fp == NULL){
printf("Cannot open file, press any key to exit!\n");
system("pause");
exit(0);
}
WSADATA wsaData;
WSAStartup( MAKEWORD(2, 2), &wsaData);
SOCKET servSock = socket(AF_INET, SOCK_STREAM, 0);
sockaddr_in sockAddr;
memset(&sockAddr, 0, sizeof(sockAddr));
sockAddr.sin_family = PF_INET;
sockAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
sockAddr.sin_port = htons(1234);
bind(servSock, (SOCKADDR*)&sockAddr, sizeof(SOCKADDR));
listen(servSock, 20);
SOCKADDR clntAddr;
int nSize = sizeof(SOCKADDR);
SOCKET clntSock = accept(servSock, (SOCKADDR*)&clntAddr, &nSize);
//循環發送數據,直到文件結尾
char buffer[BUF_SIZE] = {0}; //緩衝區
int nCount;
while( (nCount = fread(buffer, 1, BUF_SIZE, fp)) > 0 ){
send(clntSock, buffer, nCount, 0);
}
shutdown(clntSock, SD_SEND); //文件讀取完畢,斷開輸出流,向客戶端發送FIN包
recv(clntSock, buffer, BUF_SIZE, 0); //阻塞,等待客戶端接收完畢
fclose(fp);
closesocket(clntSock);
closesocket(servSock);
WSACleanup();
system("pause");
return 0;
}
客戶端代碼client.cpp:
#include <stdio.h>
#include <stdlib.h>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")
#define BUF_SIZE 1024
int main(){
//先輸入文件名,看文件是否能創建成功
char filename[100] = {0}; //文件名
printf("Input filename to save: ");
gets(filename);
FILE *fp = fopen(filename, "wb"); //以二進制方式打開(創建)文件
if(fp == NULL){
printf("Cannot open file, press any key to exit!\n");
system("pause");
exit(0);
}
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);
SOCKET sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
sockaddr_in sockAddr;
memset(&sockAddr, 0, sizeof(sockAddr));
sockAddr.sin_family = PF_INET;
sockAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
sockAddr.sin_port = htons(1234);
connect(sock, (SOCKADDR*)&sockAddr, sizeof(SOCKADDR));
//循環接收數據,直到文件傳輸完畢
char buffer[BUF_SIZE] = {0}; //文件緩衝區
int nCount;
while( (nCount = recv(sock, buffer, BUF_SIZE, 0)) > 0 ){
fwrite(buffer, nCount, 1, fp);
}
puts("File transfer success!");
//文件接收完畢後直接關閉套接字,無需調用shutdown()
fclose(fp);
closesocket(sock);
WSACleanup();
system("pause");
return 0;
}