struct sockaddr_in servaddr, clientaddr
时间: 2023-10-28 20:16:26 浏览: 49
这是一个 C 语言中的结构体定义,用于存储 IP 地址和端口号等网络地址信息。其中,servaddr 存储了服务器的地址信息,clientaddr 存储了客户端的地址信息。具体来说,sockaddr_in 结构体的定义如下:
```c
struct sockaddr_in {
sa_family_t sin_family; // 地址族(Address Family),一般为 AF_INET
uint16_t sin_port; // 端口号,使用网络字节序(Big-endian)
struct in_addr sin_addr; // IP 地址
char sin_zero[8]; // 保留位,一般设为 0
};
```
其中,struct in_addr 结构体用于存储 IP 地址,定义如下:
```c
struct in_addr {
in_addr_t s_addr; // 存储 IP 地址,使用网络字节序(Big-endian)
};
```
这些结构体定义可以在 `<netinet/in.h>` 头文件中找到。
相关问题
使用linux C,利用TCP实现一个客户端和一个服务端,客户端实现的内容为将用户输入的字符发送到服务端,服务端实现的内容为将接收到的客户端内容转化为大写字母后再发送给客户端,并且打印出发送信息的客户端IP和端口号,服务端要通过多线程实现并发访问
好的,您的问题是如何使用Linux C,利用TCP实现一个客户端和一个服务端,客户端将用户输入的字符发送到服务端,服务端将接收到的客户端内容转化为大写字母后再发送给客户端,并且打印出发送信息的客户端IP和端口号,服务端要通过多线程实现并发访问。
下面是解答:
服务端代码:
```
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <pthread.h>
#define MAXLINE 1024
#define SERV_PORT 8000
#define LISTENQ 5
void *handle_client(void *arg) {
int sockfd = *((int *)arg);
char buf[MAXLINE];
char ip[INET_ADDRSTRLEN];
struct sockaddr_in clientaddr;
socklen_t clientaddr_len = sizeof(clientaddr);
getpeername(sockfd, (struct sockaddr *)&clientaddr, &clientaddr_len);
const char *client_ip = inet_ntop(AF_INET, &clientaddr.sin_addr, ip, INET_ADDRSTRLEN);
int client_port = ntohs(clientaddr.sin_port);
printf("New connection from %s:%d\n", client_ip, client_port);
while(1) {
int n = recv(sockfd, buf, MAXLINE, 0);
if(n <= 0) {
printf("Connection closed from %s:%d\n", client_ip, client_port);
break;
}
printf("Received message from %s:%d: %s\n", client_ip, client_port, buf);
for(int i = 0; i < n; i++) {
buf[i] = toupper(buf[i]);
}
send(sockfd, buf, n, 0);
}
close(sockfd);
return NULL;
}
int main(int argc, char *argv[]) {
int listenfd;
pthread_t tid;
struct sockaddr_in servaddr;
listenfd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr));
listen(listenfd, LISTENQ);
printf("Server running on port %d...\n", SERV_PORT);
while(1) {
struct sockaddr_in clientaddr;
socklen_t clientaddr_len = sizeof(clientaddr);
int *connfd = (int *)malloc(sizeof(int));
*connfd = accept(listenfd, (struct sockaddr *)&clientaddr, &clientaddr_len);
pthread_create(&tid, NULL, handle_client, connfd);
pthread_detach(tid);
}
return 0;
}
```
客户端代码:
```
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#define MAXLINE 1024
#define SERV_PORT 8000
int main(int argc, char *argv[]) {
int sockfd;
char buf[MAXLINE];
struct sockaddr_in servaddr;
sockfd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr);
servaddr.sin_port = htons(SERV_PORT);
connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
printf("Enter message: ");
fgets(buf, MAXLINE, stdin);
send(sockfd, buf, strlen(buf), 0);
int n = recv(sockfd, buf, MAXLINE, 0);
printf("Received message: %s\n", buf);
close(sockfd);
return 0;
}
```
这里我们使用了 pthread 库来实现多线程,每次有客户端连接时,就会创建一个新的线程来处理该客户端的请求,这样可以实现并发访问。
注意,此示例中服务端无法处理多个连接,建议您进行改进。
用c++写出客户端和服务端代码利用udp协议引入txt文档进行机器人一问一答,而不是直接把文档的所有内容打印出来。
以下是基于 UDP 协议的 C++ 客户端和服务端代码实现机器人一问一答,从文本文件中读取问题和答案:
服务端代码:
```c++
#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
using namespace std;
#define PORT 8888
#define MAXSIZE 1024
int main()
{
// 打开文件
ifstream file("qa.txt");
if (!file.is_open()) {
cerr << "Failed to open file." << endl;
return -1;
}
// 读取文件内容
string line;
string question;
string answer;
while (getline(file, line)) {
if (line.empty()) {
continue;
}
if (line[0] == '#') {
if (!question.empty() && !answer.empty()) {
cout << "Q: " << question << endl;
cout << "A: " << answer << endl;
cout << endl;
question = "";
answer = "";
}
question = line.substr(1);
} else {
answer += line;
}
}
// 创建 socket
int sockfd;
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket creation failed");
exit(EXIT_FAILURE);
}
// 设置服务器地址
struct sockaddr_in servaddr;
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(PORT);
servaddr.sin_addr.s_addr = INADDR_ANY;
// 绑定 socket
if (bind(sockfd, (const struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
// 接收客户端消息并回复
char buffer[MAXSIZE];
struct sockaddr_in clientaddr;
socklen_t len = sizeof(clientaddr);
while (true) {
memset(buffer, 0, sizeof(buffer));
int n = recvfrom(sockfd, (char *)buffer, MAXSIZE, MSG_WAITALL, (struct sockaddr *)&clientaddr, &len);
buffer[n] = '\0';
cout << "Received client message: " << buffer << endl;
if (strcmp(buffer, "exit") == 0) {
break;
}
string reply = answer.empty() ? "Sorry, I don't know." : answer;
sendto(sockfd, reply.c_str(), reply.length(), MSG_CONFIRM, (const struct sockaddr *)&clientaddr, len);
}
// 关闭 socket
close(sockfd);
return 0;
}
```
客户端代码:
```c++
#include <iostream>
#include <cstring>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
using namespace std;
#define PORT 8888
#define MAXSIZE 1024
int main()
{
// 创建 socket
int sockfd;
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket creation failed");
exit(EXIT_FAILURE);
}
// 设置服务器地址
struct sockaddr_in servaddr;
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(PORT);
servaddr.sin_addr.s_addr = INADDR_ANY;
// 发送消息给服务器
char buffer[MAXSIZE];
struct sockaddr_in serv_addr;
socklen_t len = sizeof(serv_addr);
while (true) {
cout << "Please input your question: ";
cin.getline(buffer, MAXSIZE);
sendto(sockfd, buffer, strlen(buffer), MSG_CONFIRM, (const struct sockaddr *)&servaddr, len);
if (strcmp(buffer, "exit") == 0) {
break;
}
memset(buffer, 0, sizeof(buffer));
int n = recvfrom(sockfd, (char *)buffer, MAXSIZE, MSG_WAITALL, (struct sockaddr *)&serv_addr, &len);
buffer[n] = '\0';
cout << "Answer: " << buffer << endl;
}
// 关闭 socket
close(sockfd);
return 0;
}
```
注意,在运行服务端程序之前,需要创建一个名为 “qa.txt” 的文本文件,并按照以下格式填写问题和答案:
```
# Question 1
Answer 1.
# Question 2
Answer 2.
...
```
其中,“#” 后面的内容为问题,接下来的内容为答案。每个问题和答案之间需要用空行分隔开。