想看概念的去这里：
原创：黏贴请说明出处
http://www.roboby.com/linux_socket_how_to_clear_receive_buffer.html
http://www.cnblogs.com/khler/archive/2011/05/16/2047362.html
http://www.cnblogs.com/my_life/articles/5363527.html
寻找的参考文档： 看着确实难受
自己改下备注
发送方封包
PACKAGE_HEAD
pPackageHead;
//PACKAGE_HEAD
包头结构体
除了结构体也可以是别的类型以及大小
char
PackageHead[1024];
int
headLen
= sizeof(PACKAGE_HEAD);
// 结构体头部的长度
int
packgeContextLen
= strlen(packageContext);
//发送的数据的长度
pPackageHead->nDataLen
= packgeContextLen;//自己定义的包的大小
char
*packge
= (char*)malloc(headLen
+ packgeContextLen);
//包的内存分配
memset(packge, 0, headLen + packgeContextLen);
//
清空
char
*packgeCpy
= (char*)memcpy(packge,
(char*)&pPackageHead,
headLen);//拷贝包头里面的数据
packgeCpy
+= headLen;
//拷贝包内容里面的数据
packge
= (char*)memcpy(packgeCpy,
(char*)&packageContext,
packgeContextLen);
int
ret = 0;
ret
= send(m_hSocket, packge, headLen + packgeContextLen,
0); //发送包的内容
if
(ret
== SOCKET_ERROR || ret == 0)
{
return
ret;
}
// 有上面的解释下面的应该可以看懂了
接收方解包
char
PackageHead[1024];
char
PackageContext[1024*20];
int
len;
PACKAGE_HEAD
*pPackageHead;
//PACKAGE_HEAD
包头结构体
while(
m_bClose
== false
)
{
memset(PackageHead,
0, sizeof(PACKAGE_HEAD));
len = ReceiveSize(m_TcpSock,
(char*)PackageHead,
sizeof(PACKAGE_HEAD));
//接收包头
if( len == SOCKET_ERROR )
{
break;
}
if(len == 0)
{
break;
}
pPackageHead
= (PACKAGE_HEAD *)PackageHead;
memset(PackageContext,0,sizeof(PackageContext));
if(pPackageHead->nDataLen>0)
//根据包头中的数据长度，接收数据
{
len = ReceiveSize(m_TcpSock,
(char*)PackageContext,pPackageHead->nDataLen);
}
}
接收指定长度的数据函数
//接收指定长度的数据
int
ReceiveSize(SOCKET
m_hSocket, char* strData, int gLen)
{
if(strData == NULL)
return
ERR_BADPARAM;
char
*p = strData;
int
len = gLen;
int
ret = 0;
int
returnlen = 0;
while( len > 0)
{
ret = recv( m_hSocket, p+(iLen-len), iLen-returnlen, 0);
if
(ret == SOCKET_ERROR || ret == 0)
{
return
ret;
}
len -= ret;
returnlen += ret;
}
return
returnlen;
}
// 然后下面是自己写的
包定义解包封包
// 头文件
。。。。。
#define NAME_LEN 256 //linux max file name
#define TYPE char
// pack define
#pragma pack(push,1)
typedef struct packTCP
{
TYPE dataLen;
char data[NAME_LEN];
}PACK;
#pragma pack(pop)
// 包很简单dataLen 就是包头
只是个char类型当然可以自己改为结构体
//
至于版本号以及校验时间之类的传输的东西暂时不需要
// 封包
自己写的一个函数 列出服务器指定目录下的文件 传输到
客户端
int do_ls(char
*path,const int sock_fd)
{
int reG = 0;
DIR *dir;
struct dirent *ptr;
char base[COMMAND_LINE];
if( (dir=opendir(path)) == NULL )
{
perror(“ser: Open dir error—do_ls\n”);
exit(EXIT_FAILURE);
}
while( (ptr = readdir(dir)) != NULL )
{
if(strcmp(ptr->d_name,”.”) == 0 ||
strcmp(ptr->d_name,”..”)==0)
{
continue;
}
else if( ptr->d_type == 8 || ptr->d_type == 10)
{
sleep(1);
PACK pack;
TYPE packHead = 0;
// pack head len
int packHeadLen = sizeof(packHead);
memset(pack.data,’\0′,NAME_LEN);
// pack.data
memcpy(pack.data,path,strlen(path));
strncat(pack.data,”/”,1);
strncat(pack.data,ptr->d_name,strlen(ptr->d_name));
// pack data len
packHead = strlen(path) +
1 + strlen(ptr->d_name);
char *pPack = (char *)malloc(packHeadLen + packHead)
;
memset(pPack,’\0′,packHeadLen + packHead);
// copy pack head
char *pPackCp = (char *)strncpy(pPack,(char
*)&packHead,packHeadLen);
// copy pack data
pPack = (char *) strncat (
pPackCp,(char *)&(pack.data),packHead );
reG = 0;
reG = send(sock_fd,pPack,packHeadLen+packHead,0);
if( -1 == reG )
{
perror(“ser: send fail\n”);
exit(EXIT_FAILURE);
}
printf(“%d “,pPack[0]);
printf(“%s\n”,pPack+1);
free(pPack);
pPack = NULL;
}
else if( ptr->d_type == 4 )
{
memset(base,’\0′,sizeof(base));
strncpy(base,path,strlen(path));
strcat(base,”/”);
strcat(base,ptr->d_name);
do_ls(base,sock_fd);
}
}
return 4;
}
/// 解包
客户端接收来自服务器的东西进行解包
int do_sevr_ls(char *path, const int sock_fd)
{
int reG = 0;
printf(“\ncli: serverPath :\n\n”);
TYPE *pPackHead;
PACK pack;
while(1)
{
memset(pPackHead,0,sizeof(int));
char *p =(char *) pPackHead;
int pPackHeadLen = sizeof(TYPE);
int packLen = sizeof(PACK);
int recvHead = 0;
// recv pack head
recvHead =
recv(sock_fd,p+pPackHeadLen,pPackHeadLen,0);
if(recvHead == -1)
{
perror(“cli: recv fail—-do_sevr_ls\n”);
exit(EXIT_FAILURE);
}
reG = 2;
reG = strcmp(p+pPackHeadLen ,”#”);
if( 0 == reG )
{
break;
}
memset(pack.data,0,sizeof(pack.data));
int recvData = 0;
recvData = recv(sock_fd,(char
*)(pack.data),pack.dataLen,0);
printf(“%s\n”,pack.data);
}
printf(“\n\n”);
return 1;
}
//
很简单的解包和封包