linux套接字编程笔记（二）--简单的TCP套接字应用程序

客官°小女子只卖身不卖艺 2022-06-16 01:24 202阅读 0赞

# linux套接字编程笔记（二）–简单的TCP套接字应用程序 #

这里参照**linux套接字编程笔记（一）–TCP与UDP**提到的流程，编写了一个简易的C语言TCP server和client，主要是留着代码供自己后面参考，否则每次再用C或者C++写还得搜别人的代码，可能还有坑。。。

linux套接字编程笔记（一）–TCP与UDP，链接是[http://blog.csdn.net/qq\_15437667/article/details/70194698][http_blog.csdn.net_qq_15437667_article_details_70194698]

代码如下

client

#include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <errno.h>
    
    #include <netinet/in.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <sys/wait.h>
    #include <arpa/inet.h>
    #include <unistd.h>
    #include <signal.h>
    
    #define IP_SIZE (20)
    #define SERVER_LISTEN_PORT (10000)
    #define BUFFER_SIZE (4096)
    #define MAX_FILE_NAME_LEN (256)
    
    void tcpClientUploadFile(int sockFd, struct sockaddr_in *serverAddr, char *filePath);
    
    int main(int argc, char *argv[]) {
        int sockFd = 0;
        char serverIP[IP_SIZE];
        struct sockaddr_in serverAddr;
    
        if (argc == 2) {
            strcpy(serverIP, argv[1]);
        } else if (argc == 1){
            strcpy(serverIP, "127.0.0.1");
        } else {
            printf("error command\n");
            exit(-1);
        }
    
        //create socket
        sockFd = socket(AF_INET, SOCK_STREAM, 0);
        if (sockFd < 0) {
            printf("create socket failed\n");
            exit(-1);
        }
    
        /* set serverAddr */
        /* struct sockaddr { unsigned short sa_family; char sa_data[14]; }; struct sockaddr_in { short sin_family; // 2 bytes e.g. AF_INET, AF_INET6 unsigned short sin_port; // 2 bytes e.g. htons(3490) struct in_addr sin_addr; // 4 bytes see struct in_addr, below char sin_zero[8]; // 8 bytes zero this if you want to }; struct in_addr { unsigned long s_addr; // 4 bytes load with inet_pton() }; */
        serverAddr.sin_family = AF_INET;
        serverAddr.sin_port = htons(SERVER_LISTEN_PORT);
        serverAddr.sin_addr.s_addr = inet_addr(serverIP);
    
        //connect the server
        if (connect(sockFd, (struct sockaddr *)&serverAddr, sizeof(struct sockaddr)) < 0) {
            printf("connect failed\n");
            exit(-1);
        }
    
        printf("connect server success\n");
    
        //push file
        tcpClientUploadFile(sockFd, &serverAddr, "./test.go");
    
        close(sockFd);
    
        return 0;
    }
    
    void tcpClientUploadFile(int sockFd, struct sockaddr_in *serverAddr, char *filePath) {
        FILE *stream;
        char buffer[BUFFER_SIZE];
        char filename[MAX_FILE_NAME_LEN];
        int count = 0;
    
        bzero(buffer, BUFFER_SIZE);
        strcpy(filename, strrchr(filePath, '/') + 1);
        printf("filename is %s\n", filename);
        strncpy(buffer, filename, strlen(filename) > MAX_FILE_NAME_LEN ? MAX_FILE_NAME_LEN : strlen(filename));
    
        //send filename
        send(sockFd, buffer, BUFFER_SIZE, 0);
    
        stream = fopen(filePath, "r");
        if (NULL == stream) {
            printf("open file %s failed\n", filePath);
            exit(-1);
        }
    
        while((count  = fread(buffer, 1, BUFFER_SIZE, stream)) > 0) {
            //printf
            if (send(sockFd, buffer, count, 0) < 0) {
                printf("send failed\n");
                break;
            }
    
            bzero(buffer, BUFFER_SIZE);
        }
    
        printf("upload success\n");
    
        fclose(stream);
    }

server

#include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <errno.h>
    
    #include <netinet/in.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <sys/wait.h>
    #include <arpa/inet.h>
    #include <unistd.h>
    #include <signal.h>
    
    #define IP_SIZE (20)
    #define SERVER_LISTEN_PORT (10000)
    #define BUFFER_SIZE (4096)
    #define MAX_FILE_NAME_LEN (256)
    
    void tcpServerDownloadFile (int connFd, struct sockaddr_in *clientAddr, char *fileServerRoot);
    
    int main(int argc, char *argv[]) {
        /*char serverIP[IP_SIZE]; if (argc >= 2) { }*/
        char serverIP[IP_SIZE] = "127.0.0.1";
        int sockFd = 0;
        struct sockaddr_in serverAddr;
    
        bzero(&serverAddr, sizeof(serverAddr));
    
        /* create sock */
        sockFd = socket(AF_INET, SOCK_STREAM, 0);
        if (sockFd < 0) {
            perror("sock init failed!\n");
            exit(-1);
        } else {
            printf("create socket success!\n");
        }
    
        /* set serverAddr */
        /* struct sockaddr { unsigned short sa_family; char sa_data[14]; }; struct sockaddr_in { short sin_family; // 2 bytes e.g. AF_INET, AF_INET6 unsigned short sin_port; // 2 bytes e.g. htons(3490) struct in_addr sin_addr; // 4 bytes see struct in_addr, below char sin_zero[8]; // 8 bytes zero this if you want to }; struct in_addr { unsigned long s_addr; // 4 bytes load with inet_pton() }; */
        serverAddr.sin_family = AF_INET;
        serverAddr.sin_port   = htons(SERVER_LISTEN_PORT);
        serverAddr.sin_addr.s_addr = inet_addr(serverIP);
    
        //bind
        if (bind(sockFd, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) > 0) {
            perror("bind error\n");
            exit(-1);
        } else {
            printf("server bind success!\n");
        }
    
        //listen
        if(listen(sockFd, 5)) {
            printf("server listen failed, err is %d\n", errno);
            exit(-1);
        } else {
            printf("listen success\n");
        }
    
        struct sockaddr_in clientAddr;
        socklen_t          length = sizeof(clientAddr);
        int                connFd = 0;
    
        while (1) {
            //accept
            connFd = accept(sockFd, (struct sockaddr *)&clientAddr, &length);
    
            if (connFd == -1) {
                printf("accpet err\n");
                continue;
            }
    
            printf("get connection\n");
            //pull file
            tcpServerDownloadFile(connFd, &clientAddr, "./");
    
            close(connFd);       
        }
    
    
        return 0;
    }
    
    void tcpServerDownloadFile (int connFd, struct sockaddr_in *clientAddr, char *fileServerRoot) {
        char buffer[BUFFER_SIZE];
        char filename[MAX_FILE_NAME_LEN];
        char fileServerPath[MAX_FILE_NAME_LEN];
        FILE *stream = NULL;
    
        int count = 0;
        int dataLen = 0;
        int writeLen = 0;
    
        bzero(buffer, BUFFER_SIZE);
    
        count = recv(connFd, buffer, BUFFER_SIZE, 0);
    
        if (count < 0) {
            printf("recv filename failed!\n");
            exit(1);
        }
    
        strncpy(filename, buffer, strlen(buffer) > MAX_FILE_NAME_LEN? MAX_FILE_NAME_LEN : strlen(buffer));
        strcpy(fileServerPath, fileServerRoot);
        strcpy(fileServerPath, filename);
        printf("file path:\n %s\n", fileServerPath);
    
        //open a file
        stream = fopen(fileServerPath, "w");
        if (NULL == stream) {
            printf("create file failed\n");
            exit(-1);
        }
        bzero(buffer, BUFFER_SIZE);
    
        printf("start recv file\n");
    
        while((dataLen = recv(connFd, buffer, BUFFER_SIZE, 0)) > 0) {
            //if (dataLen)
            writeLen = fwrite(buffer, sizeof(char), dataLen, stream);
            if (writeLen != dataLen) {
                printf("write error, upload interupt\n");
                exit(-1);
            }
    
            bzero(buffer, BUFFER_SIZE);
        }
    
        printf("upload file ok\n");
    
        fclose(stream);
    }

> 后面扩展成多进程、多线程、通过select、epoll编程、libevent（实际上是封装了linux下的epoll和win下相应接口）都会基于该代码进行微调修改

代码在github路径下  
[https://github.com/Miss-you/network-program-test.git][https_github.com_Miss-you_network-program-test.git]

[http_blog.csdn.net_qq_15437667_article_details_70194698]: http://blog.csdn.net/qq_15437667/article/details/70194698
[https_github.com_Miss-you_network-program-test.git]: https://github.com/Miss-you/network-program-test.git