今天主要講了TCP的收發(fā)

TCP發(fā)端步驟

①socket
②connect
③send
④close

TCP收端步驟

①socket
②bind
③listen
④accept
⑤recv
⑥clise

其函數(shù)主要有

connect

int connect(int sockfd, const struct sockaddr *addr,
                   socklen_t addrlen);
  功能:
    發(fā)送鏈接請(qǐng)求
  參數(shù):
    sockfd:套接字文件描述符
    addr:目的地址存放空間首地址
    addrlen:IP地址的大小
  返回值:
    成功返回0
    失敗返回-1

send

ssize_t send(int sockfd, const void *buf, size_t len, int flags);
  功能:
    發(fā)送數(shù)據(jù)
  參數(shù):
    sockfd:文件描述符
    buf:發(fā)送數(shù)據(jù)空間首地址
    len:發(fā)送數(shù)據(jù)的長(zhǎng)度
    flags:屬性默認(rèn)為0 
  返回值:
    成功返回實(shí)際發(fā)送字節(jié)數(shù)
    失敗返回-1

recv

ssize_t recv(int sockfd, void *buf, size_t len, int flags);
  功能:
    接收數(shù)據(jù) 
  參數(shù):
    sockfd:套接字文件描述符 
    buf:存放數(shù)據(jù)空間首地址
    len:最大接收數(shù)據(jù)的長(zhǎng)度
    flags:屬性默認(rèn)為0 
  返回值:
    成功返回實(shí)際接收字節(jié)數(shù)
    失敗返回-1 
    如果對(duì)方退出,返回0 

listen

int listen(int sockfd, int backlog);
  功能:
    監(jiān)聽(tīng)客戶端發(fā)送的連接請(qǐng)求
    該函數(shù)不會(huì)阻塞
  參數(shù):
    sockfd:套接字文件描述符
    backlog:允許等待的尚未被處理的三次握手請(qǐng)求的最大個(gè)數(shù)
  返回值:
    成功返回0 
    失敗返回-1 

accept

int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
  功能:
    處理等待連接隊(duì)列中的第一個(gè)連接請(qǐng)求
    該函數(shù)具有阻塞功能(如果沒(méi)有人發(fā)送鏈接請(qǐng)求，會(huì)阻塞等待)
  參數(shù):
    socket:套接字文件描述符
    address:存放IP地址的空間首地址
    addrlen:存放IP地址大小空間首地址
  返回值:
    成功返回一個(gè)新的文件描述符
    失敗返回-1 

eg：利用TCP實(shí)現(xiàn)跨主機(jī)的文件發(fā)送

send端

#include"head.h"

int main(void)
{
	int sockfd = 0;
	FILE *fp = 0;
	int ret = 0;
	ssize_t nsize = 0;
	ssize_t nret = 0;
	char tmpbuff[4096] = {0};
	struct sockaddr_in srcaddr;
	char filename[256] = {"a.txt"};

	gets(filename);
	
	srcaddr.sin_family = AF_INET;
	srcaddr.sin_port = htons(50000);
	srcaddr.sin_addr.s_addr = inet_addr("192.168.1.152");

	sockfd = socket(AF_INET,SOCK_STREAM,0);
	if(-1 == sockfd)
	{
		perror("fail to socket");
		return -1;
	}

	ret = connect(sockfd,(struct sockaddr *)&srcaddr,sizeof(srcaddr));
	if(-1 == ret)
	{
		perror("fail to connect");
		return -1;
	}

	nsize = send(sockfd,filename,strlen(filename),0);
	if(-1 == nsize)
	{
		perror("fail to send");
		return -1;
	}

    fp = fopen(filename, "rb");
    if (fp == NULL) 
	{
        perror("fail to fopen");
        return -1;
	}


    while(1)
	{
		memset(tmpbuff,0,sizeof(tmpbuff));
		sleep(1);
		nsize = fread(tmpbuff, sizeof(char), 4096, fp);
		if(0 >= nsize)
		{
			break;
		}
			
        send(sockfd, tmpbuff,nsize, 0);
    }

	close(sockfd);
	fclose(fp);
	return 0;
}

recv端

#include"head.h"

int main(void)
{
	FILE *file = NULL;
	ssize_t nsize = 0;
	ssize_t nret = 0;
	char name[20] = {0};
	char tmpbuff[4096] = {0};
	int sockfd = 0;
	int recfd = 0;
	int ret = 0;
	struct sockaddr_in recaddr;


	recaddr.sin_family = AF_INET;
	recaddr.sin_port = htons(50000);
	recaddr.sin_addr.s_addr = INADDR_ANY;

	sockfd = socket(AF_INET,SOCK_STREAM,0);
	if(-1 == sockfd)
	{
		perror("fail to socket");
		return -1;
	}

	ret = bind(sockfd,(struct sockaddr *)&recaddr,sizeof(recaddr));
	if(-1 == ret)
	{
		perror("fail to bind");
		return -1;
	}

	ret = listen(sockfd,10);
	if(-1 == ret)
	{
		perror("fail to listen");
		return -1;
	}

	recfd = accept(sockfd,NULL,NULL);
	if(-1 == recfd)
	{
		perror("fail to accept");
		return -1;
	}

	nret = recv(recfd,name,sizeof(name),0);
	if(-1 == nret)
	{
		perror("fail to recv");
		return -1;
	}

	file = fopen(name,"wb");

	 while ((nsize = recv(recfd, tmpbuff, sizeof(tmpbuff), 0)) > 0)
    {
        if (fwrite(tmpbuff, sizeof(char), nsize, file) < nsize)
        {
            perror("fail to write file");
            fclose(file);
            close(recfd);
            close(sockfd);
            return -1;
        }
    }

	close(recfd);
	fclose(file);
	close(sockfd);

	return 0;
}

結(jié)果：

以上就是今天內(nèi)容！文章來(lái)源地址http://www.zghlxwxcb.cn/news/detail-838489.html

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