c语言实现socket服务端/客户端通过tcp传送文件

/*client.c*/
#include<netinet/in.h>                         // for sockaddr_in
#include<sys/types.h>                          // for socket
#include<sys/socket.h>                         // for socket
#include<stdio.h>                              // for printf
#include<stdlib.h>                             // for exit
#include<string.h>                             // for bzero

#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("Usage: ./%s ServerIPAddress\n", argv[0]);
exit(1);
}

// 设置一个socket地址结构client_addr, 代表客户机的internet地址和端口
struct sockaddr_in client_addr;
bzero(&client_addr, sizeof(client_addr));
client_addr.sin_family = AF_INET; // internet协议族
client_addr.sin_addr.s_addr = htons(INADDR_ANY); // INADDR_ANY表示自动获取本机地址
client_addr.sin_port = htons(0); // auto allocated, 让系统自动分配一个空闲端口

// 创建用于internet的流协议(TCP)类型socket，用client_socket代表客户端socket
int client_socket = socket(AF_INET, SOCK_STREAM, 0);
if (client_socket < 0)
{
printf("Create Socket Failed!\n");
exit(1);
}

// 把客户端的socket和客户端的socket地址结构绑定
if (bind(client_socket, (struct sockaddr*)&client_addr, sizeof(client_addr)))
{
printf("Client Bind Port Failed!\n");
exit(1);
}

// 设置一个socket地址结构server_addr,代表服务器的internet地址和端口
struct sockaddr_in  server_addr;
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;

// 服务器的IP地址来自程序的参数
if (inet_aton(argv[1], &server_addr.sin_addr) == 0)
{
printf("Server IP Address Error!\n");
exit(1);
}

server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
socklen_t server_addr_length = sizeof(server_addr);

// 向服务器发起连接请求，连接成功后client_socket代表客户端和服务器端的一个socket连接
if (connect(client_socket, (struct sockaddr*)&server_addr, server_addr_length) < 0)
{
printf("Can Not Connect To %s!\n", argv[1]);
exit(1);
}

char file_name[FILE_NAME_MAX_SIZE + 1];
bzero(file_name, sizeof(file_name));
printf("Please Input File Name On Server.\t");
scanf("%s", file_name);

char buffer[BUFFER_SIZE];
bzero(buffer, sizeof(buffer));
strncpy(buffer, file_name, strlen(file_name) > BUFFER_SIZE ? BUFFER_SIZE : strlen(file_name));
// 向服务器发送buffer中的数据，此时buffer中存放的是客户端需要接收的文件的名字
send(client_socket, buffer, BUFFER_SIZE, 0);

FILE *fp = fopen(file_name, "w");
if (fp == NULL)
{
printf("File:\t%s Can Not Open To Write!\n", file_name);
exit(1);
}

// 从服务器端接收数据到buffer中
bzero(buffer, sizeof(buffer));
int length = 0;
while(length = recv(client_socket, buffer, BUFFER_SIZE, 0))
{
if (length < 0)
{
printf("Recieve Data From Server %s Failed!\n", argv[1]);
break;
}

int write_length = fwrite(buffer, sizeof(char), length, fp);
if (write_length < length)
{
printf("File:\t%s Write Failed!\n", file_name);
break;
}
bzero(buffer, BUFFER_SIZE);
}

printf("Recieve File:\t %s From Server[%s] Finished!\n", file_name, argv[1]);

// 传输完毕，关闭socket
fclose(fp);
close(client_socket);
return 0;

}

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

#define HELLO_WORLD_SERVER_PORT    6666         //端口号
#define LENGTH_OF_LISTEN_QUEUE     20
#define BUFFER_SIZE                1024
#define FILE_NAME_MAX_SIZE         512

int main(int argc, char **argv)
{
// set socket's address information
// 设置一个socket地址结构server_addr,代表服务器internet的地址和端口
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);

// create a stream socket
// 创建用于internet的流协议(TCP)socket，用server_socket代表服务器向客户端提供服务的接口
int server_socket = socket(PF_INET, SOCK_STREAM, 0);
if (server_socket < 0)
{
printf("Create Socket Failed!\n");
exit(1);
}

// 把socket和socket地址结构绑定
if (bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr)))
{
printf("Server Bind Port: %d Failed!\n", HELLO_WORLD_SERVER_PORT);
exit(1);
}

// server_socket用于监听
if (listen(server_socket, LENGTH_OF_LISTEN_QUEUE))
{
printf("Server Listen Failed!\n");
exit(1);
}

// 服务器端一直运行用以持续为客户端提供服务
while(1)
{
// 定义客户端的socket地址结构client_addr，当收到来自客户端的请求后，调用accept
// 接受此请求，同时将client端的地址和端口等信息写入client_addr中
struct sockaddr_in client_addr;
socklen_t          length = sizeof(client_addr);

// 接受一个从client端到达server端的连接请求,将客户端的信息保存在client_addr中
// 如果没有连接请求，则一直等待直到有连接请求为止，这是accept函数的特性，可以
// 用select()来实现超时检测
// accpet返回一个新的socket,这个socket用来与此次连接到server的client进行通信
// 这里的new_server_socket代表了这个通信通道
int new_server_socket = accept(server_socket, (struct sockaddr*)&client_addr, &length);
if (new_server_socket < 0)
{
printf("Server Accept Failed!\n");
break;
}

char buffer[BUFFER_SIZE];
bzero(buffer, sizeof(buffer));
length = recv(new_server_socket, buffer, BUFFER_SIZE, 0);
if (length < 0)
{
printf("Server Recieve Data Failed!\n");
break;
}

char file_name[FILE_NAME_MAX_SIZE + 1];
bzero(file_name, sizeof(file_name));
strncpy(file_name, buffer,
strlen(buffer) > FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE : strlen(buffer));

FILE *fp = fopen(file_name, "r");
if (fp == NULL)
{
printf("File:\t%s Not Found!\n", file_name);
}
else
{
bzero(buffer, BUFFER_SIZE);
int file_block_length = 0;
while( (file_block_length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0)
{
printf("file_block_length = %d\n", file_block_length);

// 发送buffer中的字符串到new_server_socket,实际上就是发送给客户端
if (send(new_server_socket, buffer, file_block_length, 0) < 0)
{
printf("Send File:\t%s Failed!\n", file_name);
break;
}

bzero(buffer, sizeof(buffer));
}
fclose(fp);
printf("File:\t%s Transfer Finished!\n", file_name);
}

close(new_server_socket);
}

close(server_socket);

return 0;
}