转自:http://blog.csdn.net/taiyang1987912/article/details/49738351
一、简介
通过socket扫描本机打开的tcp端口号,模拟用户名、密码登录服务器的过程、socket文件传输及模仿http服务器。
二、详解
1、Linux下tcp端口扫描
(1)scanport.c:
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- // 端口扫描程序,只支持扫描TCP端口
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <unistd.h>
- #include <errno.h>
- #include <pthread.h>
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <netinet/in.h>
- #include <arpa/inet.h>
- // 定义一个端口区间信息
- typedef struct _port_segment {
- struct in_addr dest_ip; // 目标IP
- unsigned short int min_port; // 起始端口
- unsigned short int max_port; // 最大端口
- } port_segment;
- /*自定义的错误处理函数*/
- void my_err(const char * err_string, int line)
- {
- fprintf(stderr, "line:%d ", line);
- perror(err_string);
- exit(1);
- }
- /*
- * 描 述:扫描某一IP地址上的某一个端口的函数
- * 返回值:-1 出错
- * 0 目标端口未打开
- * 1 目标端口已打开
- */
- int do_scan(struct sockaddr_in serv_addr)
- {
- int conn_fd;
- int ret;
- // 创建一个TCP套接字
- conn_fd = socket(AF_INET, SOCK_STREAM,0);
- if (conn_fd < 0) {
- my_err("socket", __LINE__);
- }
- // 向服务器端发送连接请求
- if ((ret = connect(conn_fd, (struct sockaddr *)&serv_addr, sizeof (struct sockaddr))) < 0 ) {
- if (errno == ECONNREFUSED) { // 目标端口未打开
- close(conn_fd);
- return 0;
- } else { // 其他错误
- close(conn_fd);
- return -1;
- }
- } else if (ret == 0){
- printf("port %d found in %s\n", ntohs(serv_addr.sin_port),
- inet_ntoa(serv_addr.sin_addr));
- close(conn_fd);
- return 1;
- }
- return -1; // 实际执行不到这里,只是为了消除编译程序时产生的警告
- }
- // 执行扫描的线程,扫描某一区间的端口
- void * scaner(void *arg)
- {
- unsigned short int i;
- struct sockaddr_in serv_addr;
- port_segment portinfo; // 端口信息
- // 读取端口区间信息
- memcpy(&portinfo, arg, sizeof(struct _port_segment));
- // 初始化服务器端地址结构
- memset(&serv_addr, 0, sizeof (struct sockaddr_in));
- serv_addr.sin_family = AF_INET;
- serv_addr.sin_addr.s_addr = portinfo.dest_ip.s_addr;
- //printf("******serv_addr.sin_addr.s_addr=%s\n", serv_addr.sin_addr.s_addr);
- //printf("*******portinfo.min_port=%d, portinfo.max_port=%d\n", portinfo.min_port, portinfo.max_port);
- for (i=portinfo.min_port; i<=portinfo.max_port; i++) {
- serv_addr.sin_port = htons(i);
- if (do_scan(serv_addr) < 0) {
- continue; // 出错则退出进程
- }
- }
- return NULL;
- }
- /*
- * 命令行参数:-m 最大端口, -a 目标主机的IP地址, -n 最大线程数
- */
- int main(int argc, char **argv)
- {
- pthread_t* thread; // 指向所有的线程ID
- int max_port; // 最大端口号
- int thread_num; // 最大线程数
- int seg_len; // 端口区间长度
- struct in_addr dest_ip; // 目标主机IP
- int i;
- // 检查参数个数
- if (argc != 7) {
- printf("Usage: [-m] [max_port] [-a] [serv_address] [-n] [thread_number]\n");
- exit(1);
- }
- // 解析命令行参数
- for (i=1; i<argc; i++) {
- if (strcmp("-m", argv[i]) == 0) {
- max_port = atoi(argv[i+1]); // 将字符串转化为对应的整数
- if (max_port < 0 || max_port >= 65535) { //65535会导致死循环
- printf("Usage:invalid max dest port\n");
- exit(1);
- }
- continue;
- }
- if (strcmp("-a", argv[i]) == 0) {
- if (inet_aton(argv[i+1], &dest_ip) == 0) {
- printf("Usage:invalid dest ip address\n");
- exit(1);
- }
- continue;
- }
- if (strcmp("-n", argv[i]) == 0) {
- thread_num = atoi(argv[i+1]);
- if (thread_num <= 0) {
- printf("Usage:invalid thread_number\n");
- exit(1);
- }
- continue;
- }
- }
- // 如果输入的最大端口号小于线程数,则将线程数设为最大端口号
- if (max_port < thread_num) {
- thread_num = max_port;
- }
- seg_len = max_port / thread_num;
- if ( (max_port%thread_num) != 0 ) {
- thread_num += 1;
- }
- //printf("max_port=%d, seg_len=%d, thread_num = %d\n", max_port, seg_len, thread_num);
- // 分配存储所有线程ID的内存空间
- thread = (pthread_t*)malloc(thread_num*sizeof(pthread_t));
- // 创建线程,根据最大端口号和线程数分配每个线程扫描的端口区间
- port_segment *portinfo = (port_segment*)malloc(thread_num * sizeof(port_segment));
- for (i=0; i<thread_num; i++) {
- portinfo[i].dest_ip = dest_ip;
- portinfo[i].min_port = i*seg_len + 1;
- //printf("portinfo.min_port=%d, seg_len=%d, i = %d\n", portinfo[i].min_port, seg_len, i);
- if (i == thread_num - 1) {
- portinfo[i].max_port = max_port;
- } else {
- portinfo[i].max_port = portinfo[i].min_port + seg_len - 1;
- }
- // 创建线程
- //if (pthread_create(&thread[i], NULL, scaner, (void *)(portinfo + i)) != 0) {
- if (pthread_create(&thread[i], NULL, scaner, (void *)(&portinfo[i])) != 0) {
- my_err("pthread_create", __LINE__);
- }
- }
- for (i=0; i<thread_num; i++) {
- // 主线程等待子线程结束
- pthread_join(thread[i], NULL);
- }
- free(portinfo);
- return 0;
- }
(2)编译运行
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- gcc -o scanport scanport.c -lpthread
- ./scanport -m 65534 -a 127.0.0.1 -n 1
可以通过netstat查看网络相关信息,netstat -tnlp或netstat -tnlpc比较打开的tcp端口号。
2、模拟用户名、密码登录
(1)服务器server.c: [html] view plaincopy
- // Client/Server模型的服务器端
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <unistd.h>
- #include <stdio.h>
- #include <string.h>
- #include <netinet/in.h>
- #include <arpa/inet.h>
- #include <errno.h>
- #include <stdlib.h>
- #define BUFSIZE 1024
- #define SERV_PORT 4507 // 服务器端的端口
- #define LISTENQ 12 // 连接请求队列的最大长度
- #define INVALID_USERINFO 'n' // 用户信息无效
- #define VALID_USERINFO 'y' // 用户信息有效
- #define USERNAME 0 // 接收到的是用户名
- #define PASSWORD 1 // 接收到的是密码
- struct userinfo { // 保存用户名和密码的结构体
- char username[32];
- char password[32];
- };
- struct userinfo users[ ] = {
- {"linux", "unix"},
- {"4507", "4508"},
- {"clh", "clh"},
- {"xl", "xl"},
- {" "," "} // 以只含一个空格的字符串作为数组的结束标志
- };
- /*自定义的错误处理函数*/
- void my_err(const char * err_string, int line)
- {
- fprintf(stderr, "line:%d ", line);
- perror(err_string);
- exit(1);
- }
- /*
- * 函数名: my_recv
- * 描 述 : 从套接字上读取一次数据(以'\n'为结束标志)
- * 参 数 : conn_fd -- 从该连接套接字上接收数据
- * data_buf -- 读取到的数据保存在此缓冲中
- * len -- data_buf所指向的空间长度
- * 返回值: 出错返回-1, 服务器端已关闭连接则返回0, 成功返回读取的字节数
- */
- int my_recv(int conn_fd, char *data_buf, int len)
- {
- static char recv_buf[BUFSIZE]; // 自定义缓冲区,BUFSIZE定义在my_recv.h中
- static char *pread; // 指向下一次读取数据的位置
- static int len_remain = 0; // 自定义缓冲区中剩余字节数
- int i;
- // 如果自定义缓冲区中没有数据,则从套接字读取数据
- if (len_remain <= 0) {
- if ((len_remain =recv(conn_fd, recv_buf, sizeof (recv_buf), 0)) < 0) {
- my_err("recv", __LINE__);
- } else if (len_remain == 0) { // 目的计算机端的socket连接关闭
- return 0;
- }
- pread = recv_buf; // 重新初始化pread指针
- }
- // 从自定义缓冲区中读取一次数据
- for (i=0; *pread != '\n'; i++) {
- if (i > len) { // 防止指针越界
- return -1;
- }
- data_buf[i] = *pread++;
- len_remain--;
- }
- // 去除结束标志
- len_remain--;
- pread++;
- return i; // 读取成功
- }
- // 查找用户名是否存在,存在返回该用户名的下标,不存在则返回-1,出错返回-2
- int find_name(const char *name)
- {
- int i;
- if (name == NULL) {
- printf("in find_name, NULL pointer");
- return -2;
- }
- for (i=0; users[i].username[0] != ' ';i++) {
- if (strncmp(users[i].username, name, strlen(users[i].username)) == 0) {
- return i;
- }
- }
- return -1;
- }
- // 发送数据
- void send_data(int conn_fd, const char *string)
- {
- if (send(conn_fd, string, strlen(string), 0) < 0) {
- my_err("send", __LINE__); // my_err函数在my_recv.h中声明
- }
- }
- int main()
- {
- int sock_fd, conn_fd;
- int optval;
- int flag_recv = USERNAME; // 标识接收到的是用户还是密码
- int ret;
- int name_num;
- pid_t pid;
- socklen_t cli_len;
- struct sockaddr_in cli_addr, serv_addr;
- char recv_buf[128];
- // 创建一个TCP套接字
- sock_fd = socket(AF_INET, SOCK_STREAM,0);
- if (sock_fd < 0) {
- my_err("socket", __LINE__);
- }
- // 设置该套接字使之可以重新绑定端口
- optval = 1;
- if (setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR,
- (void *)&optval, sizeof(int)) < 0) {
- my_err("setsockopt", __LINE__);
- }
- // 初始化服务器端地址结构
- memset(&serv_addr, 0, sizeof (struct sockaddr_in));
- serv_addr.sin_family = AF_INET;
- serv_addr.sin_port = htons(SERV_PORT);
- serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
- // 将套接字绑定到本地端口
- if (bind(sock_fd, (struct sockaddr *)&serv_addr,
- sizeof (struct sockaddr_in)) < 0) {
- my_err("bind", __LINE__);
- }
- // 将套接字转化为监听套接字
- if (listen(sock_fd, LISTENQ) < 0) {
- my_err("listen", __LINE__);
- }
- cli_len = sizeof (struct sockaddr_in);
- while (1) {
- // 通过accept接受客户端的连接请求,并返回连接套接字用于收发数据
- conn_fd = accept(sock_fd, (struct sockaddr *)&cli_addr, &cli_len);
- if (conn_fd < 0) {
- my_err("accept", __LINE__);
- }
- printf("accept a new client, ip:%s\n", inet_ntoa(cli_addr.sin_addr));
- // 创建一个子进程处理刚刚接受的连接请求
- if ( (pid = fork()) == 0 ) { // 子进程
- while(1) {
- memset(recv_buf, 0, sizeof(recv_buf));
- if ((ret = recv(conn_fd, recv_buf, sizeof (recv_buf), 0)) < 0) {
- perror("recv");
- exit(1);
- }
- recv_buf[ret-1] = '\0'; // 将数据结束标志'\n'替换成字符串结束标志
- if (flag_recv == USERNAME) { // 接收到的是用户名
- name_num = find_name(recv_buf);
- switch (name_num) {
- case -1:
- send_data(conn_fd, "n\n");
- break;
- case -2:
- exit(1);
- break;
- default:
- send_data(conn_fd, "y\n");
- flag_recv = PASSWORD;
- break;
- }
- } else if (flag_recv == PASSWORD) { // 接收到的是密码
- if (strncmp(users[name_num].password, recv_buf, strlen(users[name_num].password)) == 0) {
- send_data(conn_fd, "y\n");
- send_data(conn_fd, "Welcome login my tcp server\n");
- printf("%s login\n", users[name_num].username);
- break; // 跳出while循环
- } else
- send_data(conn_fd, "n\n");
- }
- }
- close(sock_fd);
- close(conn_fd);
- exit(0); // 结束子进程
- } else { // 父进程关闭刚刚接受的连接请求,执行accept等待其他连接请求
- close(conn_fd);
- }
- }
- return 0;
- }
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- #include <sys/types.h>
- #include <sys/socket.h>
- #include <unistd.h>
- #include <stdio.h>
- #include <string.h>
- #include <errno.h>
- #include <stdlib.h>
- #include <netinet/in.h>
- #include <arpa/inet.h>
- #define BUFSIZE 1024
- #define INVALID_USERINFO 'n' // 用户信息无效
- #define VALID_USERINFO 'y' // 用户信息有效
- /*自定义的错误处理函数*/
- void my_err(const char * err_string, int line)
- {
- fprintf(stderr, "line:%d ", line);
- perror(err_string);
- exit(1);
- }
- /*
- * 函数名: my_recv
- * 描 述 : 从套接字上读取一次数据(以'\n'为结束标志)
- * 参 数 : conn_fd -- 从该连接套接字上接收数据
- * data_buf -- 读取到的数据保存在此缓冲中
- * len -- data_buf所指向的空间长度
- * 返回值: 出错返回-1, 服务器端已关闭连接则返回0, 成功返回读取的字节数
- */
- int my_recv(int conn_fd, char *data_buf, int len)
- {
- static char recv_buf[BUFSIZE]; // 自定义缓冲区,BUFSIZE定义在my_recv.h中
- static char *pread; // 指向下一次读取数据的位置
- static int len_remain = 0; // 自定义缓冲区中剩余字节数
- int i;
- // 如果自定义缓冲区中没有数据,则从套接字读取数据
- if (len_remain <= 0) {
- if ((len_remain =recv(conn_fd, recv_buf, sizeof (recv_buf), 0)) < 0) {
- my_err("recv", __LINE__);
- } else if (len_remain == 0) { // 目的计算机端的socket连接关闭
- return 0;
- }
- pread = recv_buf; // 重新初始化pread指针
- }
- // 从自定义缓冲区中读取一次数据
- for (i=0; *pread != '\n'; i++) {
- if (i > len) { // 防止指针越界
- return -1;
- }
- data_buf[i] = *pread++;
- len_remain--;
- }
- // 去除结束标志
- len_remain--;
- pread++;
- return i; // 读取成功
- }
- /*获取用户输入存入到buf,buf的长度为len,用户输入数据以'\n'为结束标志*/
- int get_userinfo(char *buf, int len)
- {
- int i;
- int c;
- if (buf == NULL) {
- return -1;
- }
- i = 0;
- while ( ((c = getchar()) != '\n') && (c != EOF) && (i < len-2) ) {
- buf[i++] = c;
- }
- buf[i++] = '\n';
- buf[i++] = '\0';
- return 0;
- }
- // 输入用户名,然后通过fd发送出去
- void input_userinfo(int conn_fd, const char *string)
- {
- char input_buf[32];
- char recv_buf[BUFSIZE];
- int flag_userinfo;
- int count = 0;
- // 输入用户信息直到正确为止
- do {
- printf("%s:", string);
- if (get_userinfo(input_buf, 32) < 0) {
- printf("error return from get_userinfo\n");
- exit(1);
- }
- if (send(conn_fd, input_buf, strlen(input_buf), 0) < 0) {
- my_err("send", __LINE__);
- }
- // 从连接套接字上读取一次数据
- if (my_recv(conn_fd, recv_buf, sizeof (recv_buf)) < 0) {
- printf("data is too long\n");
- exit(1);
- }
- if (recv_buf[0] == VALID_USERINFO) {
- flag_userinfo = VALID_USERINFO;
- } else {
- count++;
- if (count >= 3) {
- printf("input %s error for three times,exit!\n", string);
- exit(-1);
- }
- printf("%s error,input again!\n", string);
- flag_userinfo= INVALID_USERINFO;
- }
- } while(flag_userinfo == INVALID_USERINFO);
- }
- int main(int argc, char **argv)
- {
- int i;
- int ret;
- int conn_fd;
- int serv_port;
- struct sockaddr_in serv_addr;
- char recv_buf[BUFSIZE];
- // 检查参数个数
- if (argc != 5) {
- printf("Usage: [-p] [serv_port] [-a] [serv_address]\n");
- exit(1);
- }
- // 初始化服务器端地址结构
- memset(&serv_addr, 0, sizeof (struct sockaddr_in));
- serv_addr.sin_family = AF_INET;
- // 从命令行获取服务器端的端口与地址
- for (i=1; i<argc; i++) {
- if (strcmp("-p", argv[i]) == 0) {
- serv_port = atoi(argv[i+1]);
- if (serv_port < 0 || serv_port > 65535) {
- printf("invalid serv_addr.sin_port\n");
- exit(1);
- } else {
- serv_addr.sin_port = htons(serv_port);
- }
- continue;
- }
- if (strcmp("-a", argv[i]) == 0) {
- if (inet_aton(argv[i+1], &serv_addr.sin_addr) == 0) {
- printf("invalid server ip address\n");
- exit(1);
- }
- continue;
- }
- }
- // 检测是否少输入了某项参数
- if (serv_addr.sin_port == 0 || serv_addr.sin_addr.s_addr == 0) {
- printf("Usage: [-p] [serv_addr.sin_port] [-a][serv_address]\n");
- exit(1);
- }
- // 创建一个TCP套接字
- conn_fd = socket(AF_INET, SOCK_STREAM,0);
- if (conn_fd < 0) {
- my_err("socket", __LINE__);
- }
- // 向服务器端发送连接请求
- if (connect(conn_fd, (struct sockaddr *)&serv_addr, sizeof (struct sockaddr)) < 0) {
- my_err("connect", __LINE__);
- }
- // 输入用户名和密码
- input_userinfo(conn_fd, "username");
- input_userinfo(conn_fd, "password");
- // 读取欢迎信息并打印出来
- if ((ret = my_recv(conn_fd, recv_buf, sizeof (recv_buf))) < 0) {
- printf("data is too long\n");
- exit(1);
- }
- for (i=0; i<ret; i++) {
- printf("%c", recv_buf[i]);
- }
- printf("\n");
- close(conn_fd);
- return 0;
- }
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- gcc -o server server.c
- ./server
- gcc -o client client.c
- ./client -p 4507 -a 127.0.0.1
3、socket文件传输(从server端下载文件)
(1)file_server.c: [html] view plaincopy
- #include <netinet/in.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <strings.h>
- #define HELLO_WORLD_SERVER_PORT 6666
- #define LENGTH_OF_LISTENQ_QUEUE 20
- #define BUFFER_SIZE 1024
- #define FILE_NAME_MAX_SIZE 512
- int main(int argc, char *argv[])
- {
- struct sockaddr_in server_addr;
- bzero(&server_addr, sizeof(server_addr));
- server_addr.sin_family = AF_INET;
- server_addr.sin_addr.s_addr = htons(INADDR_ANY);
- server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
- int server_socket = socket(AF_INET, SOCK_STREAM, 0);
- if (server_socket < 0) {
- printf("create socket failed!\n");
- exit(1);
- }
- if (bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr))) {
- printf("bind socket failed!\n");
- exit(1);
- }
- if (listen(server_socket, LENGTH_OF_LISTENQ_QUEUE)) {
- printf("listen socket failed!\n");
- exit(1);
- }
- while (1) {
- struct sockaddr_in client_addr;
- socklen_t length = sizeof(client_addr);
- int new_server_scoket = accept(server_socket, (struct sockaddr*)&client_addr, &length);
- if (new_server_scoket < 0) {
- printf("accept socket failed!\n");
- break;
- }
- char buffer[BUFFER_SIZE];
- bzero(buffer, BUFFER_SIZE);
- length = recv(new_server_scoket, buffer, BUFFER_SIZE, 0);
- if (length < 0) {
- printf("recv data failed!\n");
- break;
- }
- char file_name[FILE_NAME_MAX_SIZE + 1];
- bzero(file_name, FILE_NAME_MAX_SIZE + 1);
- strncpy(file_name, buffer, strlen(file_name) > FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE : strlen(buffer));
- FILE *fp = fopen(file_name, "r");
- if (fp == NULL) {
- printf("File: %s not found\n", file_name);
- }
- else {
- bzero(buffer, BUFFER_SIZE);
- int file_length = 0;
- while((file_length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0) {
- printf("file_length = %d\n", file_length);
- if (send(new_server_scoket, buffer, file_length, 0) < 0) {
- printf("send file: %s failed\n", file_name);
- break;
- }
- bzero(buffer, BUFFER_SIZE);
- }
- fclose(fp);
- printf("file: %s trandfer finished\n", file_name);
- }
- close(new_server_scoket);
- }
- close(server_socket);
- return 0;
- }
[html] view plaincopy
- #include <netinet/in.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <strings.h>
- #define HELLO_WORLD_SERVER_PORT 6666
- #define BUFFER_SIZE 1024
- #define FILE_NAME_MAX_SIZE 512
- int main(int argc, char *argv[])
- {
- if (argc != 2) {
- printf("use:[./run][server_ipaddress]\n");
- exit(1);
- }
- struct sockaddr_in client_addr;
- bzero(&client_addr,sizeof(client_addr));
- client_addr.sin_family = AF_INET;
- if (inet_aton(argv[1], &client_addr.sin_addr) == 0) {
- printf("server ip address error!\n");
- exit(1);
- }
- client_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
- socklen_t client_addr_length = sizeof(client_addr);
- int client_socket = socket(AF_INET, SOCK_STREAM, 0);
- if (client_socket < 0) {
- printf("create socket failed\n");
- exit(1);
- }
- if (connect(client_socket, (struct sockaddr*)&client_addr, client_addr_length) < 0) {
- printf("can not connect to address\n");
- exit(1);
- }
- char file_name[FILE_NAME_MAX_SIZE + 1];
- bzero(file_name, FILE_NAME_MAX_SIZE + 1);
- printf("please input file name:");
- scanf("%s", file_name);
- char buffer[BUFFER_SIZE];
- bzero(buffer, BUFFER_SIZE);
- strncpy(buffer, file_name, strlen(file_name) > BUFFER_SIZE ? BUFFER_SIZE : strlen(file_name));
- send(client_socket, buffer, BUFFER_SIZE, 0);
- FILE *fp = fopen(file_name, "w");
- if (fp == NULL) {
- printf("file can not open\n");
- exit(1);
- }
- bzero(buffer, BUFFER_SIZE);
- int length = 0;
- while (length = recv(client_socket, buffer, BUFFER_SIZE, 0)) {
- if (length < 0) {
- printf("recv failed\n");
- break;
- }
- int write_length = fwrite(buffer, sizeof(char), length, fp);
- if (write_length < length) {
- printf("file write failed\n");
- break;
- }
- bzero(buffer, BUFFER_SIZE);
- }
- printf("recieve file: %s from server %s finished!\n", file_name, argv[1]);
- close(fp);
- close(client_socket);
- return 0;
- }
[html] view plaincopy
- gcc -o server file_server.c
- ./server
- gcc -o client file_client.c
- ./client 127.0.0.1
client显示:
注:server和client放在不同的目录下,需要传输的文件yang.txt与server在同一目录下。
4、模拟http服务器
(1)http服务器server.c:
[html] view plaincopy
- #include <stdarg.h>
- #include <errno.h>
- #include <stdio.h>
- #include <fcntl.h>
- #include <unistd.h>
- #include <string.h>
- #include <time.h>
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <dirent.h>
- #include <errno.h>
- #include <netinet/in.h>
- #include <sys/socket.h>
- #include <resolv.h>
- #include <arpa/inet.h>
- #include <stdlib.h>
- #include <signal.h>
- #include <strings.h>
- #define DEFAULTIP "127.0.0.1"
- #define DEFAULTPORT "4040"
- #define DEFAULTBACK "10"
- #define DEFAULTDIR "/tmp/http/dir"
- #define DEFAULTLOG "/tmp/http/log"
- void prterrmsg(char *msg);
- #define prterrmsg(msg) { perror(msg); abort(); }
- void wrterrmsg(char *msg);
- #define wrterrmsg(msg) { fputs(msg, logfp); fputs(strerror(errno), logfp);fflush(logfp); abort(); }
- void prtinfomsg(char *msg);
- #define prtinfomsg(msg) { fputs(msg, stdout); }
- void wrtinfomsg(char *msg);
- #define wrtinfomsg(msg) { fputs(msg, logfp); fflush(logfp);}
- #define MAXBUF 1024
- char buffer[MAXBUF + 1];
- char *host = 0;
- char *port = 0;
- char *back = 0;
- char *dirroot = 0;
- char *logdir = 0;
- unsigned char daemon_y_n = 0;
- FILE *logfp;
- #define MAXPATH 150
- /*----------------------------------------
- *--- dir_up - 查找dirpath所指目录的上一级目录
- *----------------------------------------
- */
- char *dir_up(char *dirpath)
- {
- static char Path[MAXPATH];
- int len;
- strcpy(Path, dirpath);
- len = strlen(Path);
- if (len > 1 && Path[len - 1] == '/')
- len--;
- while (Path[len - 1] != '/' && len > 1)
- len--;
- Path[len] = 0;
- return Path;
- }
- /*------------------------------------------------------
- *--- AllocateMemory - 分配空间并把d所指的内容复制
- *------------------------------------------------------
- */
- void AllocateMemory(char **s, int l, char *d)
- {
- *s = (char *)malloc(l + 1);
- bzero(*s, l + 1);
- memcpy(*s, d, l);
- }
- /*------------------------------------------------------
- *--- GiveResponse - 把Path所指的内容发送到client_sock去
- *-------------------如果Path是一个目录,则列出目录内容
- *-------------------如果Path是一个文件,则下载文件
- *------------------------------------------------------
- */
- void GiveResponse(FILE * client_sock, char *Path)
- {
- struct dirent *dirent;
- struct stat info;
- char Filename[MAXPATH];
- DIR *dir;
- int fd, len, ret;
- char *p, *realPath, *realFilename, *nport;
- /* 获得实际工作目录或文件 */
- len = strlen(dirroot) + strlen(Path) + 1;
- realPath = (char *)malloc(len + 1);
- bzero(realPath, len + 1);
- sprintf(realPath, "%s/%s", dirroot, Path);
- /* 获得实际工作端口 */
- len = strlen(port) + 1;
- nport = (char *)malloc(len + 1);
- bzero(nport, len + 1);
- sprintf(nport, ":%s", port);
- /* 获得实际工作目录或文件的信息以判断是文件还是目录 */
- if (stat(realPath, &info)) {
- fprintf(client_sock,
- "HTTP/1.1 200 OK\r\nServer: DAS by Centos\r\nConnection: close\r\n\r\n"
- "<html>"
- "<meta charset=\"UTF-8\"/>"
- "<head><title>%d - %s</title></head>"
- "<body><font size=+4>Linux下目录访问服务器</font><br><hr width=\"100%%\"><br><center>"
- "<table border cols=3 width=\"100%%\">"
- , errno, strerror(errno));
- fprintf(client_sock,
- "</table><font color=\"CC0000\" size=+2>请向管理员咨询为何出现如下错误提示:\n%s %s</font></body></html>",
- Path, strerror(errno));
- goto out;
- }
- /* 处理浏览文件请求,即下载文件 */
- if (S_ISREG(info.st_mode)) {
- fd = open(realPath, O_RDONLY);
- len = lseek(fd, 0, SEEK_END);
- p = (char *) malloc(len + 1);
- bzero(p, len + 1);
- lseek(fd, 0, SEEK_SET);
- ret = read(fd, p, len);
- close(fd);
- fprintf(client_sock,
- "HTTP/1.1 200 OK\r\nServer: DAS by Centos\r\nConnection: keep-alive\r\nContent-type: application/*\r\nContent-Length:%d\r\n\r\n",
- len);
- fwrite(p, len, 1, client_sock);
- free(p);
- } else if (S_ISDIR(info.st_mode)) {
- /* 处理浏览目录请求 */
- dir = opendir(realPath);
- fprintf(client_sock,
- "HTTP/1.1 200 OK\r\nServer: DAS by Centos\r\nConnection: close\r\n\r\n"
- "<html>"
- "<meta charset=\"UTF-8\"/>"
- "<head><title>%s</title></head>"
- "<body><font size=+4>Linux下目录访问服务器</font><br><hr width=\"100%%\"><br><center>"
- "<table border cols=3 width=\"100%%\">", Path);
- fprintf(client_sock,
- "<caption><font size=+3>目录 %s</font></caption>\n",
- Path);
- fprintf(client_sock,
- "<tr><td>名称</td><td>大小</td><td>修改时间</td></tr>\n");
- if (dir == 0) {
- fprintf(client_sock,
- "</table><font color=\"CC0000\" size=+2>%s</font></body></html>",
- strerror(errno));
- return;
- }
- /* 读取目录里的所有内容 */
- while ((dirent = readdir(dir)) != 0) {
- if (strcmp(Path, "/") == 0)
- sprintf(Filename, "/%s", dirent->d_name);
- else
- sprintf(Filename, "%s/%s", Path, dirent->d_name);
- fprintf(client_sock, "<tr>");
- len = strlen(dirroot) + strlen(Filename) + 1;
- realFilename = (char *)malloc(len + 1);
- bzero(realFilename, len + 1);
- sprintf(realFilename, "%s/%s", dirroot, Filename);
- if (stat(realFilename, &info) == 0) {
- if (strcmp(dirent->d_name, "..") == 0)
- fprintf(client_sock,
- "<td><a href=\"http://%s%s%s\">(parent)</a></td>",
- host, atoi(port) == 80 ? "" : nport,
- dir_up(Path));
- else
- fprintf(client_sock,
- "<td><a href=\"http://%s%s%s\">%s</a></td>",
- host, atoi(port) == 80 ? "" : nport, Filename,
- dirent->d_name);
- if (S_ISDIR(info.st_mode))
- fprintf(client_sock, "<td>目录</td>");
- else if (S_ISREG(info.st_mode))
- fprintf(client_sock, "<td>%d</td>", info.st_size);
- else if (S_ISLNK(info.st_mode))
- fprintf(client_sock, "<td>链接</td>");
- else if (S_ISCHR(info.st_mode))
- fprintf(client_sock, "<td>字符设备</td>");
- else if (S_ISBLK(info.st_mode))
- fprintf(client_sock, "<td>块设备</td>");
- else if (S_ISFIFO(info.st_mode))
- fprintf(client_sock, "<td>FIFO</td>");
- else if (S_ISSOCK(info.st_mode))
- fprintf(client_sock, "<td>Socket</td>");
- else
- fprintf(client_sock, "<td>(未知)</td>");
- fprintf(client_sock, "<td>%s</td>", ctime(&info.st_ctime));
- }
- fprintf(client_sock, "</tr>\n");
- free(realFilename);
- }
- fprintf(client_sock, "</table></center></body></html>");
- } else {
- /* 既非常规文件又非目录,禁止访问 */
- fprintf(client_sock,
- "HTTP/1.1 200 OK\r\nServer: DAS by Centos\r\nConnection: close\r\n\r\n"
- "<html>"
- "<meta charset=\"UTF-8\"/>"
- "<head><title>permission denied</title></head>"
- "<body><font size=+4>Linux下目录访问服务器</font><br><hr width=\"100%%\"><br><center>"
- "<table border cols=3 width=\"100%%\">");
- fprintf(client_sock,
- "</table><font color=\"CC0000\" size=+2>你访问的资源'%s'被禁止访问,请联系管理员解决!</font></body></html>",
- Path);
- }
- out:
- free(realPath);
- free(nport);
- }
- /*------------------------------------------------------
- *--- getoption - 分析取出程序的参数
- *------------------------------------------------------
- */
- void getoption(int argc, char **argv)
- {
- // int c, len;
- // char *p = 0;
- //
- // opterr = 0;
- // while (1) {
- // int option_index = 0;
- // static struct option long_options[] = {
- // {"host", 1, 0, 0},
- // {"port", 1, 0, 0},
- // {"back", 1, 0, 0},
- // {"dir", 1, 0, 0},
- // {"log", 1, 0, 0},
- // {"daemon", 0, 0, 0},
- // {0, 0, 0, 0}
- // };
- // /* 本程序支持如一些参数:
- // * --host IP地址 或者 -H IP地址
- // * --port 端口 或者 -P 端口
- // * --back 监听数量 或者 -B 监听数量
- // * --dir 网站根目录 或者 -D 网站根目录
- // * --log 日志存放路径 或者 -L 日志存放路径
- // * --daemon 使程序进入后台运行模式
- // */
- // c = getopt_long(argc, argv, "H:P:B:D:L",
- // long_options, &option_index);
- // if (c == -1 || c == '?')
- // break;
- //
- // if(optarg) len = strlen(optarg);
- // else len = 0;
- //
- // if ((!c && !(strcasecmp(long_options[option_index].name, "host")))
- // || c == 'H')
- // p = host = malloc(len + 1);
- // else if ((!c
- // &&
- // !(strcasecmp(long_options[option_index].name, "port")))
- // || c == 'P')
- // p = port = malloc(len + 1);
- // else if ((!c
- // &&
- // !(strcasecmp(long_options[option_index].name, "back")))
- // || c == 'B')
- // p = back = malloc(len + 1);
- // else if ((!c
- // && !(strcasecmp(long_options[option_index].name, "dir")))
- // || c == 'D')
- // p = dirroot = malloc(len + 1);
- // else if ((!c
- // && !(strcasecmp(long_options[option_index].name, "log")))
- // || c == 'L')
- // p = logdir = malloc(len + 1);
- // else if ((!c
- // &&
- // !(strcasecmp
- // (long_options[option_index].name, "daemon")))) {
- // daemon_y_n = 1;
- // continue;
- // }
- // else
- // break;
- // bzero(p, len + 1);
- // memcpy(p, optarg, len);
- // }
- }
- int main(int argc, char **argv)
- {
- struct sockaddr_in addr;
- int sock_fd, addrlen;
- /* 获得程序工作的参数,如 IP 、端口、监听数、网页根目录、目录存放位置等 */
- //getoption(argc, argv);
- if (!host) {
- addrlen = strlen(DEFAULTIP);
- AllocateMemory(&host, addrlen, DEFAULTIP);
- }
- if (!port) {
- addrlen = strlen(DEFAULTPORT);
- AllocateMemory(&port, addrlen, DEFAULTPORT);
- }
- if (!back) {
- addrlen = strlen(DEFAULTBACK);
- AllocateMemory(&back, addrlen, DEFAULTBACK);
- }
- if (!dirroot) {
- addrlen = strlen(DEFAULTDIR);
- AllocateMemory(&dirroot, addrlen, DEFAULTDIR);
- }
- if (!logdir) {
- addrlen = strlen(DEFAULTLOG);
- AllocateMemory(&logdir, addrlen, DEFAULTLOG);
- }
- printf
- ("host=%s port=%s back=%s dirroot=%s logdir=%s %s是后台工作模式(进程ID:%d)\n",
- host, port, back, dirroot, logdir, daemon_y_n?"":"不", getpid());
- /* fork() 两次处于后台工作模式下 */
- if (daemon_y_n) {
- if (fork())
- exit(0);
- if (fork())
- exit(0);
- close(0), close(1), close(2);
- logfp = fopen(logdir, "a+");
- if (!logfp)
- exit(0);
- }
- /* 处理子进程退出以免产生僵尸进程 */
- signal(SIGCHLD, SIG_IGN);
- /* 创建 socket */
- if ((sock_fd = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
- if (!daemon_y_n) {
- prterrmsg("socket()");
- } else {
- wrterrmsg("socket()");
- }
- }
- /* 设置端口快速重用 */
- addrlen = 1;
- setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &addrlen,
- sizeof(addrlen));
- addr.sin_family = AF_INET;
- addr.sin_port = htons(atoi(port));
- addr.sin_addr.s_addr = htonl(INADDR_ANY);//htonl(INADDR_ANY);
- addrlen = sizeof(struct sockaddr_in);
- /* 绑定地址、端口等信息 */
- if (bind(sock_fd, (struct sockaddr *) &addr, addrlen) < 0) {
- if (!daemon_y_n) {
- prterrmsg("bind()");
- } else {
- wrterrmsg("bind()");
- }
- }
- /* 开启临听 */
- if (listen(sock_fd, atoi(back)) < 0) {
- if (!daemon_y_n) {
- prterrmsg("listen()");
- } else {
- wrterrmsg("listen()");
- }
- }
- while (1) {
- int len;
- int new_fd;
- addrlen = sizeof(struct sockaddr_in);
- /* 接受新连接请求 */
- new_fd = accept(sock_fd, (struct sockaddr *) &addr, (socklen_t *)&addrlen);
- if (new_fd < 0) {
- if (!daemon_y_n) {
- prterrmsg("accept()");
- } else {
- wrterrmsg("accept()");
- }
- break;
- }
- bzero(buffer, MAXBUF + 1);
- sprintf(buffer, "连接来自于: %s:%d\n",
- inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
- if (!daemon_y_n) {
- prtinfomsg(buffer);
- } else {
- wrtinfomsg(buffer);
- }
- /* 产生一个子进程去处理请求,当前进程继续等待新的连接到来 */
- if (!fork()) {
- bzero(buffer, MAXBUF + 1);
- puts("recving...");
- if ((len = recv(new_fd, buffer, MAXBUF, 0)) > 0) {
- FILE *ClientFP = fdopen(new_fd, "w");
- if (ClientFP == NULL) {
- if (!daemon_y_n) {
- prterrmsg("fdopen()");
- } else {
- prterrmsg("fdopen()");
- }
- } else {
- char Req[MAXPATH + 1] = "";
- sscanf(buffer, "GET %s HTTP", Req);
- bzero(buffer, MAXBUF + 1);
- sprintf(buffer, "请求取文件: \"%s\"\n", Req);
- if (!daemon_y_n) {
- prtinfomsg(buffer);
- } else {
- wrtinfomsg(buffer);
- }
- /* 处理用户请求 */
- GiveResponse(ClientFP, Req);
- fclose(ClientFP);
- }
- }
- puts("go out");
- exit(0);
- }
- close(new_fd);
- }
- close(sock_fd);
- return 0;
- }
[html] view plaincopy
- gcc -o server server.c
- ./server
在浏览器中输入:http://127.0.0.1:4040
注:需建立/tmp/http/dir和/tmp/http/log文件夹,并在dir下建立目录树。
然后在浏览器中点击文件即可下载文件,点击目录可进一步进行查看。点击parent可以返回到上一级目录。
(3)http客户端client.c(从服务器上下载文件并重新命名)
[html] view plaincopy
- #include <stdlib.h>
- #include <stdio.h>
- #include <netdb.h>
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <sys/socketvar.h>
- #include <strings.h>
- #include <arpa/inet.h>
- #include <unistd.h>
- #include <string.h>
- #include<errno.h>
- int main(int argc, char *argv[])
- {
- char buffer[1024] = {0};
- char host_addr[256] = {0};
- char host_file[256] = {0};
- char local_file[256] = {0};
- int sockfd;
- int send, totalsend;
- int nbytes;
- char request[1024] = {0};
- struct sockaddr_in server_addr;
- struct hostent *host;
- if (argc != 2) {
- fprintf(stderr, "Usage:%s web-address!\n", argv[0]);
- exit(1);
- }
- int portnumber = 4040;
- strcpy(host_addr, argv[1]);
- strcpy(host_file, "server.c");
- if ((host = gethostbyname(argv[1])) == NULL) {
- fprintf(stderr,"Gethostname error\n", strerror(errno));
- exit(1);
- }
- char ip_str[32] = {0};
- printf("address: %s\n", inet_ntop(host->h_addrtype, host->h_addr, ip_str, sizeof(ip_str)));
- if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
- fprintf(stderr,"Socket Error:%s!\n",strerror(errno));
- exit(1);
- }
- bzero(&server_addr, sizeof(server_addr));
- server_addr.sin_family = AF_INET;
- server_addr.sin_port = htons(portnumber);
- server_addr.sin_addr = *((struct in_addr *)host->h_addr);
- if (connect(sockfd, (struct sockaddr *)(&server_addr), sizeof(struct sockaddr)) == -1) {
- fprintf(stderr,"Connect Error:%s!\n",strerror(errno));
- exit(1);
- }
- sprintf(request, "GET /%s HTTP/1.1\r\nAccept: */*\r\nAccept-Language: zh-cn\r\n \
- User-Agent: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)\r\n \
- Host: %s:%d\r\nConnection: Close\r\n\r\n", host_file, host_addr, portnumber);
- strcpy(local_file, "local.txt");
- send = 0;
- totalsend = 0;
- nbytes = strlen(request);
- while (totalsend < nbytes) {
- send = write(sockfd, request + totalsend, nbytes - totalsend);
- if (send == -1) {
- printf("send error:%s!\n", strerror(errno));
- exit(0);
- }
- totalsend += send;
- printf("%d bytes send OK!\n", totalsend);
- }
- FILE * fp = fopen(local_file, "a");
- if(!fp) {
- printf("create file error:%s!\n", strerror(errno));
- return 0;
- }
- //printf("The following is the response header:\n");
- int i = 0;
- /* 连接成功了,接收http响应,response */
- while((nbytes = read(sockfd, buffer, 1)) == 1) {
- if (i < 4) {
- if (buffer[0] == '\r' || buffer[0] == '\n')
- i++;
- else
- i = 0;
- //printf("%c", buffer[0]);
- }
- else {
- fwrite(buffer, 1, 1, fp);/*将http主体信息写入文件*/
- //printf("%c", buffer[0]);
- i++;
- if(i % 1024 == 0)
- fflush(fp); /**每1K时存盘一次**/
- }
- }
- printf("\n");
- fclose(fp);
- /* 结束通讯 */
- close(sockfd);
- return 0;
- }
在客户端程序的当前的目录下下载了local.txt,其中的内容是服务器上server.c文件的内容。
三、总结
(1)上述代码在centos上测试通过,只是功能实现,代码执行效率暂未考虑。(2)若有建议,请留言,在此先感谢!