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ftp_serv.c
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ftp_serv.c
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#include <linux/net.h>
#include <linux/in.h>
#include <linux/socket.h>
#include <net/sock.h>
#include "ftp_utils.h"
#include "ftp_serv.h"
#include "ftp_list.h"
void ftpUSER(struct client_context* ctx, struct socket* clientsock)
{
char* response = "331 placeholder\r\n";
printk(KERN_INFO "kftp: Received USER\n");
kernel_send(clientsock,response,strlen(response));
}
void ftpPASS(struct client_context* ctx, struct socket* clientsock)
{
char* response = "230 placeholder\r\n";
printk(KERN_INFO "kftp: Received PASS\n");
kernel_send(clientsock,response,strlen(response));
ctx->authorized = 1;
}
void ftpSYST(struct client_context* ctx, struct socket* clientsock)
{
char* response = "215 UNIX Type: L8\r\n";
printk(KERN_INFO "kftp: Received SYST\n");
kernel_send(clientsock,response,strlen(response));
}
void ftpPASV(struct client_context* ctx, struct socket* clientsock)
{
if (!check_client_auth(ctx)){
return;
}
printk(KERN_INFO "kftp: Received PASV\n");
create_passive_data_connection(ctx, get_random_open_port(), false);
}
void ftpEPSV(struct client_context* ctx, struct socket* clientsock)
{
if (!check_client_auth(ctx)){
return;
}
printk(KERN_INFO "kftp: Received EPSV\n");
create_passive_data_connection(ctx, get_random_open_port(), true);
}
void ftpQUIT(struct client_context* ctx, struct socket* clientsock)
{
char* response = "221 Quit Acknowledged\r\n";
printk(KERN_INFO "kftp: Received QUIT\n");
kernel_send(clientsock,response,strlen(response));
}
void ftpTYPE(struct client_context* ctx, struct socket* clientsock)
{
char* response = "200 MODE SET TO I\r\n";
printk(KERN_INFO "kftp: Received TYPE\n");
kernel_send(clientsock,response,strlen(response));
}
void ftpRETR(struct client_context* ctx, struct socket* clientsock, const char* path)
{
char* response_open = "150 Opening connection\r\n";
char* response_file_open_fail = "550 Failed to open file\r\n";
char* response_file_transfer_success = "226 File download successful\r\n";
char message[256];
struct file* file = kernel_retr_file(path);
if (!check_client_auth(ctx)){
clean_up_dtp(ctx);
return;
}
if (!check_dtp(ctx))
{
clean_up_dtp(ctx);
return;
}
printk(KERN_INFO "kftp: Received RETR\n");
printk(KERN_INFO "Transferring file: %s\n", path);
int err = kernel_accept(ctx->dataconnserver,&ctx->dataconnclient,0);
if (err < 0)
{
printk(KERN_ERR "kftp: failed to register new client!\n");
clean_up_dtp(ctx);
return;
}
else
{
printk(KERN_INFO "kftp: new client accepted: %p!\n",clientsock);
}
if (!file)
{
printk(KERN_INFO "kftp: WARN: failed to open file: %s!\n",path);
kernel_send(ctx->controlconnclient,response_file_open_fail,strlen(response_file_open_fail));
clean_up_dtp(ctx);
return;
}
kernel_send(ctx->controlconnclient,response_open,strlen(response_open));
loff_t pos = 0;
while (1) {
memset(message,0,256);
int ret = kernel_retr_read_file(file, message, 256, &pos);
printk(KERN_INFO "Fetching %d bytes at offset %d\n",ret,pos);
if (ret <= 0)
break;
kernel_send(ctx->dataconnclient, message,256);
}
kernel_send(ctx->controlconnclient,response_file_transfer_success,strlen(response_file_transfer_success));
clean_up_dtp(ctx);
}
void ftpLIST(struct client_context* ctx, struct socket* clientsock, const char* path)
{
char* response_open = "150 Opening connection\r\n";
char* response_file_open_fail = "550 Failed to open file\r\n";
char* response_file_transfer_success = "226 directory list complete\r\n";
char message[256];
if (!check_client_auth(ctx)){
clean_up_dtp(ctx);
return;
}
if (!check_dtp(ctx))
{
clean_up_dtp(ctx);
return;
}
printk(KERN_INFO "kftp: Received LIST\n");
int err = kernel_accept(ctx->dataconnserver,&ctx->dataconnclient,0);
if (err < 0)
{
printk(KERN_ERR "kftp: failed to register new client!\n");
clean_up_dtp(ctx);
return;
}
else
{
printk(KERN_INFO "kftp: new client accepted: %p!\n",clientsock);
}
kernel_send(ctx->controlconnclient,response_open,strlen(response_open));
memset(message, 0, 256);
int readdir_res = ftp_readdir(path, ctx->dataconnclient);
kernel_send(ctx->dataconnclient, message,256);
kernel_send(ctx->controlconnclient,response_file_transfer_success,strlen(response_file_transfer_success));
clean_up_dtp(ctx);
}
int create_passive_data_connection(struct client_context* ctx, int data_port, bool extended){
struct sockaddr_in serv;
char response[256];
sock_create(PF_INET, SOCK_STREAM,IPPROTO_TCP,&ctx->dataconnserver);
if (!ctx->dataconnserver)
{
printk(KERN_ERR "kftp: socket creation failed!\n");
return -1;
}
printk(KERN_INFO "kftp: data socket initialized!\n");
serv.sin_addr.s_addr = 0;
serv.sin_family = AF_INET;
serv.sin_port = htons(data_port);
int bind = kernel_bind(ctx->dataconnserver,(struct sockaddr*) &serv,sizeof(serv));
if (bind < 0)
{
printk(KERN_ERR "kftp: failed to set up data connection\n");
return -1;
}
printk(KERN_INFO "kftp: data connection binding successful\n");
kernel_listen(ctx->dataconnserver, 5);
if (extended)
{
sprintf(response,"229 Entering Extended Passive Mode (|||%d|)\r\n",data_port);
}
else{
sprintf(response,"227 Entering Passive Mode (127,0,0,1,%d,%d)\r\n",(data_port>>8)&0xff,data_port&0xff);
}
printk(KERN_INFO "kftp: PASV response - %s\n",response);
kernel_send(ctx->controlconnclient,response,strlen(response));
return 0;
}
int check_client_auth(struct client_context* ctx)
{
if (ctx->authorized == 1)
return 1;
char* response = "530 Not authorized\r\n";
kernel_send(ctx->controlconnclient,response,strlen(response));
return 0;
}
int check_dtp(struct client_context* ctx)
{
if (ctx->dataconnserver)
return 1;
char* response = "425 Server DTP not open (Use PASV)\r\n";
kernel_send(ctx->controlconnclient,response,strlen(response));
return 0;
}
void clean_up_dtp(struct client_context* ctx)
{
if (ctx->dataconnclient){
sock_release(ctx->dataconnclient);
ctx->dataconnclient = NULL;
}
if (ctx->dataconnserver){
sock_release(ctx->dataconnserver);
ctx->dataconnserver = NULL;
}
}