《TCP IP网络编程》第七章

**第七章: TCP/IP网络编程**

在前六章中，我们已经学习了如何使用TCP/IP协议栈进行网络通信。然而，实际的应用程序往往需要更复杂的功能，如连接管理、数据传输控制等。在本章中，我们将重点讨论这些主题。

###7.1 TCP连接管理TCP连接是通过三次握手建立的，这个过程涉及到客户端和服务器之间的协商。下面是一个简单的例子：

c// client.c#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT8080int main() {
 int sockfd;
 struct sockaddr_in server_addr;

 // 创建socket sockfd = socket(AF_INET, SOCK_STREAM,0);
 if (sockfd < 0) {
 perror("socket");
 exit(1);
 }

 // 初始化服务器地址 server_addr.sin_family = AF_INET;
 server_addr.sin_port = htons(PORT);
 inet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr);

 // 连接服务器 if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
 perror("connect");
 exit(1);
 }

 printf("Connected to server
");

 return0;
}

c// server.c#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT8080int main() {
 int sockfd, newsockfd;
 struct sockaddr_in server_addr, client_addr;

 // 创建socket sockfd = socket(AF_INET, SOCK_STREAM,0);
 if (sockfd < 0) {
 perror("socket");
 exit(1);
 }

 // 初始化服务器地址 server_addr.sin_family = AF_INET;
 server_addr.sin_port = htons(PORT);
 inet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr);

 // 绑定端口 if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
 perror("bind");
 exit(1);
 }

 // 监听连接 listen(sockfd,3);

 printf("Listening for connections...
");

 while (1) {
 socklen_t addrlen = sizeof(client_addr);
 newsockfd = accept(sockfd, (struct sockaddr *)&client_addr, &addrlen);
 if (newsockfd < 0) {
 perror("accept");
 continue;
 }

 printf("Connected to client
");

 // 处理客户端请求 char buffer[256];
 read(newsockfd, buffer,255);
 printf("%s", buffer);

 close(newsockfd);
 }

 return0;
}

c// client.c#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT8080int main() {
 int sockfd;
 struct sockaddr_in server_addr;

 // 创建socket sockfd = socket(AF_INET, SOCK_STREAM,0);
 if (sockfd < 0) {
 perror("socket");
 exit(1);
 }

 // 初始化服务器地址 server_addr.sin_family = AF_INET;
 server_addr.sin_port = htons(PORT);
 inet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr);

 // 连接服务器 if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
 perror("connect");
 exit(1);
 }

 printf("Connected to server
");

 // 设置窗口大小 int window_size =1024;
 setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, &window_size, sizeof(window_size));

 // 发送数据 char buffer[256];
 strcpy(buffer, "Hello, server!");
 send(sockfd, buffer, strlen(buffer),0);

 return0;
}

c// server.c#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT8080int main() {
 int sockfd, newsockfd;
 struct sockaddr_in server_addr, client_addr;

 // 创建socket sockfd = socket(AF_INET, SOCK_STREAM,0);
 if (sockfd < 0) {
 perror("socket");
 exit(1);
 }

 // 初始化服务器地址 server_addr.sin_family = AF_INET;
 server_addr.sin_port = htons(PORT);
 inet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr);

 // 绑定端口 if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
 perror("bind");
 exit(1);
 }

 // 监听连接 listen(sockfd,3);

 printf("Listening for connections...
");

 while (1) {
 socklen_t addrlen = sizeof(client_addr);
 newsockfd = accept(sockfd, (struct sockaddr *)&client_addr, &addrlen);
 if (newsockfd < 0) {
 perror("accept");
 continue;
 }

 printf("Connected to client
");

 // 设置窗口大小 int window_size =1024;
 setsockopt(newsockfd, SOL_SOCKET, SO_RCVBUF, &window_size, sizeof(window_size));

 // 接收数据 char buffer[256];
 recv(newsockfd, buffer,255,0);
 printf("%s", buffer);

 close(newsockfd);
 }

 return0;
}