linux网络编程--tcp/udp编程模型

tcp 模型如下：

上面的模型已经很清楚了

具体函数用法就不细说了

请看tcp简单的例子：

其中server.c

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

#define err_log(errlog) do{perror(errlog); exit(1);}while(0)
#define N 128

// ./server 192.168.0.196 10000

int main(int argc, const char *argv[])
{
　　int sockfd;
　　int confd;
　　struct sockaddr_in serveraddr, clientaddr;
　　char buf[N] = {};

if(argc != 3)
{
fprintf(stderr, "Usage:%s serverip port. ", argv[0]);
return -1;
}

if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
err_log("fail to socket");
}

printf("sockfd = %d ", sockfd);

serveraddr.sin_family = AF_INET;
serveraddr.sin_addr.s_addr = inet_addr(argv[1]);
serveraddr.sin_port = htons(atoi(argv[2]));

if(bind(sockfd, (struct sockaddr*)&serveraddr, sizeof(serveraddr)) < 0)
{
err_log("fail to bind");
}

if(listen(sockfd, 10) < 0)
{
err_log("fail to listen");
}

socklen_t addrlen = sizeof(struct sockaddr);
if((confd = accept(sockfd, (struct sockaddr *)&clientaddr, &addrlen)) < 0)
{
err_log("fail to accept");
}

printf("confd = %d , %s --> %d ", confd , inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port));

while(1)
{
if(recv(confd, buf, N, 0) < 0)
{
err_log("fail to recv");
}
printf("From client:%s ", buf);
if(strncmp(buf, "quit", 4) == 0)
{
break;
}
strcat(buf, " from server...");
if(send(confd, buf, N, 0) < 0)
{
err_log("fail to send. ");
}
}

close(sockfd);

return 0;
}

其中client.c如下

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

#define err_log(errlog) do{perror(errlog); exit(1);}while(0)
#define N 128

// ./client 192.168.0.196 10000

int main(int argc, const char *argv[])
{
　　int sockfd;
　　int confd;
　　struct sockaddr_in serveraddr, clientaddr;
　　char buf[N] = {0};

if(argc != 3)

{

fprintf(stderr, "Usage:%s serverip port. ", argv[0]);

return -1;

}

if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)

{

err_log("fail to socket");

}

printf("sockfd = %d ", sockfd);

serveraddr.sin_family = AF_INET;

serveraddr.sin_addr.s_addr = inet_addr(argv[1]);

serveraddr.sin_port = htons(atoi(argv[2]));

if(connect(sockfd, (struct sockaddr*)&serveraddr, sizeof(serveraddr)) < 0)

{

err_log("fail to connect");

}

while(1)

{

printf("Input >");

fgets(buf, N, stdin);

buf[strlen(buf)-1] = '';

if(send(sockfd, buf, N, 0) < 0)

{

err_log("fail to send");

}

if(strncmp(buf, "quit", 4) == 0)

{

break;

}

if(recv(sockfd, buf, N, 0) < 0)

{

err_log("fail to recv");

}

printf("%s ", buf);

}

close(sockfd);

return 0;

}

 

udp模型如下

其中server.c

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

#define err_log(errlog) do{perror(errlog); exit(1);}while(0)
#define N 128

int main(int argc, const char *argv[])
{
int sockfd;
struct sockaddr_in serveraddr;
struct sockaddr_in clientaddr;
socklen_t addrlen = sizeof(clientaddr);
char buf[N] = {};

if(argc < 3)
{
fprintf(stderr, "usage:%s serverip port. ", argv[0]);
return -1;
}

if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
{
err_log("fail to socket");
}

serveraddr.sin_family = AF_INET;
serveraddr.sin_addr.s_addr = inet_addr(argv[1]);
serveraddr.sin_port = htons(atoi(argv[2]));

if(bind(sockfd, (struct sockaddr*)&serveraddr, sizeof(serveraddr)) < 0)
{
err_log("fail to bind");
}

while(1)
{
if(recvfrom(sockfd, buf, N, 0, (struct sockaddr*)&clientaddr, &addrlen) < 0)
{
err_log("fail to recvfrom");
}

printf("From clientaddr:%s ", buf);
strcat(buf, " from server...");

if(strncmp(buf, "quit", 4) == 0)
{
break;
}

if(sendto(sockfd, buf, N, 0, (struct sockaddr *)&clientaddr, addrlen) < 0)
{
err_log("fail to sendto");
}

}

close(sockfd);

return 0;
}

 其中client.c 如下：

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

#define err_log(errlog) do{perror(errlog); exit(1);}while(0)
#define N 128

int main(int argc, const char *argv[])
{
int sockfd;
struct sockaddr_in serveraddr;
struct sockaddr_in clientaddr;
socklen_t addrlen = sizeof(clientaddr);
char buf[N] = {};

if(argc < 3)
{
fprintf(stderr, "usage:%s serverip port. ", argv[0]);
return -1;
}

if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
{
err_log("fail to socket");
}

serveraddr.sin_family = AF_INET;
serveraddr.sin_addr.s_addr = inet_addr(argv[1]);
serveraddr.sin_port = htons(atoi(argv[2]));

while(1)
{
printf("Input > ");
fgets(buf, N, stdin);
buf[strlen(buf)-1] = '';

if(sendto(sockfd, buf, N, 0, (struct sockaddr *)&serveraddr, addrlen) < 0)
{
err_log("fail to sendto");
}

if(strncmp(buf, "quit", 4) == 0)
{
break;
}

if(recvfrom(sockfd, buf, N, 0, NULL, NULL) < 0)
{
err_log("fail to recvfrom");
}

printf("%s ", buf);

}

close(sockfd);

return 0;
}