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/**
******************************************************************************
* @file LwIP/LwIP_TFTP_Server/Src/tftpserver.c
* @author MCD Application Team
* @brief basic tftp server implementation for IAP (only Write Req supported)
******************************************************************************
* @attention
*
* Copyright (c) 2017 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
#include "tftpserver.h"
#include "tftputils.h"
#include "ff.h"
#include "stm32f4xx.h"
#include <string.h>
typedef struct
{
int op; /* RRQ/WRQ */
/* last block read */
char data[TFTP_DATA_PKT_LEN_MAX];
uint32_t data_len;
/* destination ip:port */
ip_addr_t to_ip;
int to_port;
/* next block number */
int block;
/* total number of bytes transferred */
int tot_bytes;
/* timer interrupt count when last packet was sent */
/* this should be used to resend packets on timeout */
unsigned long long last_time;
}tftp_connection_args;
FATFS filesystem;
FIL file_SD, file_CR;
DIR dir_1, dir_2;
/* UDPpcb to be binded with port 69 */
struct udp_pcb *UDPpcb;
/* tftp_errorcode error strings */
char *tftp_errorcode_string[] = {
"not defined",
"file not found",
"access violation",
"disk full",
"illegal operation",
"unknown transfer id",
"file already exists",
"no such user",
};
void recv_callback_tftp(void *arg, struct udp_pcb *upcb, struct pbuf *pkt_buf, const ip_addr_t *addr, u16_t port);
/**
* @brief sends a TFTP message
* @param upcb: pointer on a udp pcb
* @param to_ip: pointer on remote IP address
* @param to_port: pointer on remote port
* @param buf: pointer on buffer where to create the message
* @param err: error code of type tftp_errorcode
* @retval error code
*/
err_t tftp_send_message(struct udp_pcb *upcb, const ip_addr_t *to_ip, unsigned short to_port, char *buf, unsigned short buflen)
{
err_t err;
struct pbuf *pkt_buf; /* Chain of pbuf's to be sent */
/* PBUF_TRANSPORT - specifies the transport layer */
pkt_buf = pbuf_alloc(PBUF_TRANSPORT, buflen, PBUF_POOL);
if (!pkt_buf) /*if the packet pbuf == NULL exit and end transmission */
return ERR_MEM;
/* Copy the original data buffer over to the packet buffer's payload */
memcpy(pkt_buf->payload, buf, buflen);
/* Sending packet by UDP protocol */
err = udp_sendto(upcb, pkt_buf, to_ip, to_port);
/* free the buffer pbuf */
pbuf_free(pkt_buf);
return err;
}
/**
* @brief construct an error message into buf
* @param buf: pointer on buffer where to create the message
* @param err: error code of type tftp_errorcode
* @retval
*/
int tftp_construct_error_message(char *buf, tftp_errorcode err)
{
int errorlen;
/* Set the opcode in the 2 first bytes */
tftp_set_opcode(buf, TFTP_ERROR);
/* Set the errorcode in the 2 second bytes */
tftp_set_errorcode(buf, err);
/* Set the error message in the last bytes */
tftp_set_errormsg(buf, tftp_errorcode_string[err]);
/* Set the length of the error message */
errorlen = strlen(tftp_errorcode_string[err]);
/* return message size */
return 4 + errorlen + 1;
}
/**
* @brief Sends a TFTP error message
* @param upcb: pointer on a udp pcb
* @param to: pointer on remote IP address
* @param to_port: pointer on remote port
* @param err: tftp error code
* @retval error value
*/
int tftp_send_error_message(struct udp_pcb *upcb, const ip_addr_t *to, int to_port, tftp_errorcode err)
{
char buf[512];
int error_len;
/* construct error */
error_len = tftp_construct_error_message(buf, err);
/* send error message */
return tftp_send_message(upcb, to, to_port, buf, error_len);
}
/**
* @brief Sends TFTP data packet
* @param upcb: pointer on a udp pcb
* @param to: pointer on remote IP address
* @param to_port: pointer on remote udp port
* @param block: block number
* @param buf: pointer on data buffer
* @param buflen: buffer length
* @retval error value
*/
int tftp_send_data_packet(struct udp_pcb *upcb, const ip_addr_t *to, int to_port, unsigned short block,
char *buf, int buflen)
{
char packet[TFTP_DATA_PKT_LEN_MAX]; /* (512+4) bytes */
/* Set the opcode 3 in the 2 first bytes */
tftp_set_opcode(packet, TFTP_DATA);
/* Set the block numero in the 2 second bytes */
tftp_set_block(packet, block);
/* Set the data message in the n last bytes */
tftp_set_data_message(packet, buf, buflen);
/* Send DATA packet */
return tftp_send_message(upcb, to, to_port, packet, buflen + 4);
}
/**
* @brief Sends TFTP ACK packet
* @param upcb: pointer on a udp pcb
* @param to: pointer on remote IP address
* @param to_port: pointer on remote udp port
* @param block: block number
* @retval error value
*/
int tftp_send_ack_packet(struct udp_pcb *upcb, const ip_addr_t *to, int to_port, unsigned short block)
{
/* create the maximum possible size packet that a TFTP ACK packet can be */
char packet[TFTP_ACK_PKT_LEN];
/* define the first two bytes of the packet */
tftp_set_opcode(packet, TFTP_ACK);
/* Specify the block number being ACK'd.
* If we are ACK'ing a DATA pkt then the block number echoes that of the DATA pkt being ACK'd (duh)
* If we are ACK'ing a WRQ pkt then the block number is always 0
* RRQ packets are never sent ACK pkts by the server, instead the server sends DATA pkts to the
* host which are, obviously, used as the "acknowledgement" */
tftp_set_block(packet, block);
return tftp_send_message(upcb, to, to_port, packet, TFTP_ACK_PKT_LEN);
}
/**
* @brief Cleanup after end of TFTP read operation
* @param upcb: pointer on udp pcb
* @param args: pointer on a structure of type tftp_connection_args
* @retval None
*/
void tftp_cleanup_rd(struct udp_pcb *upcb, tftp_connection_args *args)
{
/* close the filesystem */
f_close(&file_SD);
f_mount(NULL, (TCHAR const*)"",0);
/* Free the tftp_connection_args structure reserved for */
mem_free(args);
/* Disconnect the udp_pcb*/
udp_disconnect(upcb);
/* close the connection */
udp_remove(upcb);
udp_recv(UDPpcb, recv_callback_tftp, NULL);
}
/**
* @brief Cleanup after end of TFTP write operation
* @param upcb: pointer on udp pcb
* @param args: pointer on a structure of type tftp_connection_args
* @retval None
*/
void tftp_cleanup_wr(struct udp_pcb *upcb, tftp_connection_args *args)
{
/* close the filesystem */
f_close(&file_CR);
f_mount(NULL, (TCHAR const*)"",0);
/* Free the tftp_connection_args structure reserved for */
mem_free(args);
/* Disconnect the udp_pcb*/
udp_disconnect(upcb);
/* close the connection */
udp_remove(upcb);
/* reset the callback function */
udp_recv(UDPpcb, recv_callback_tftp, NULL);
}
/**
* @brief sends next data block during TFTP READ operation
* @param upcb: pointer on a udp pcb
* @param args: pointer on structure of type tftp_connection_args
* @param to_ip: pointer on remote IP address
* @param to_port: pointer on remote udp port
* @retval None
*/
void tftp_send_next_block(struct udp_pcb *upcb, tftp_connection_args *args,
const ip_addr_t *to_ip, u16_t to_port)
{
/* Function to read 512 bytes from the file to send (file_SD), put them
* in "args->data" and return the number of bytes read */
f_read(&file_SD, (uint8_t*)args->data, TFTP_DATA_LEN_MAX, (UINT*)(&args->data_len));
/* NOTE: We need to send data packet even if args->data_len = 0*/
/* sEndTransferthe data */
tftp_send_data_packet(upcb, to_ip, to_port, args->block, args->data, args->data_len);
}
/**
* @brief receive callback during tftp read operation (not on standard port 69)
* @param arg: pointer on argument passed to callback
* @param udp_pcb: pointer on the udp pcb
* @param pkt_buf: pointer on the received pbuf
* @param addr: pointer on remote IP address
* @param port: pointer on remote udp port
* @retval None
*/
void rrq_recv_callback(void *arg, struct udp_pcb *upcb, struct pbuf *p,
const ip_addr_t *addr, u16_t port)
{
/* Get our connection state */
tftp_connection_args *args = (tftp_connection_args *)arg;
if (tftp_is_correct_ack(p->payload, args->block))
{
/* increment block # */
args->block++;
}
else
{
/* we did not receive the expected ACK, so
do not update block #. This causes the current block to be resent. */
}
/* if the last read returned less than the requested number of bytes
* (i.e. TFTP_DATA_LEN_MAX), then we've sent the whole file and we can quit
*/
if (args->data_len < TFTP_DATA_LEN_MAX)
{
/* Clean the connection*/
tftp_cleanup_rd(upcb, args);
pbuf_free(p);
}
/* if the whole file has not yet been sent then continue */
tftp_send_next_block(upcb, args, addr, port);
pbuf_free(p);
}
/**
* @brief receive callback during tftp write operation (not on standard port 69)
* @param arg: pointer on argument passed to callback
* @param udp_pcb: pointer on the udp pcb
* @param pkt_buf: pointer on the received pbuf
* @param addr: pointer on remote IP address
* @param port: pointer on remote port
* @retval None
*/
void wrq_recv_callback(void *arg, struct udp_pcb *upcb, struct pbuf *pkt_buf, const ip_addr_t *addr, u16_t port)
{
tftp_connection_args *args = (tftp_connection_args *)arg;
int n = 0;
/* we expect to receive only one pbuf (pbuf size should be
configured > max TFTP frame size */
if (pkt_buf->len != pkt_buf->tot_len)
{
return;
}
/* Does this packet have any valid data to write? */
if ((pkt_buf->len > TFTP_DATA_PKT_HDR_LEN) &&
(tftp_extract_block(pkt_buf->payload) == (args->block + 1)))
{
/* write the received data to the file */
f_write(&file_CR, (char*)pkt_buf->payload + TFTP_DATA_PKT_HDR_LEN, pkt_buf->len - TFTP_DATA_PKT_HDR_LEN, (UINT*)&n);
if (n <= 0)
{
tftp_send_error_message(upcb, addr, port, TFTP_ERR_FILE_NOT_FOUND);
/* close the connection */
tftp_cleanup_wr(upcb, args); /* close the connection */
}
/* update our block number to match the block number just received */
args->block++;
/* update total bytes */
(args->tot_bytes) += (pkt_buf->len - TFTP_DATA_PKT_HDR_LEN);
}
else if (tftp_extract_block(pkt_buf->payload) == (args->block + 1))
{
/* update our block number to match the block number just received */
args->block++;
}
/* Send the appropriate ACK pkt (the block number sent in the ACK pkt echoes
* the block number of the DATA pkt we just received - see RFC1350)
* NOTE!: If the DATA pkt we received did not have the appropriate block
* number, then the args->block (our block number) is never updated and
* we simply send "duplicate ACK" which has the same block number as the
* last ACK pkt we sent. This lets the host know that we are still waiting
* on block number args->block+1.
*/
tftp_send_ack_packet(upcb, addr, port, args->block);
/* If the last write returned less than the maximum TFTP data pkt length,
* then we've received the whole file and so we can quit (this is how TFTP
* signals the end of a transfer!)
*/
if (pkt_buf->len < TFTP_DATA_PKT_LEN_MAX)
{
tftp_cleanup_wr(upcb, args);
pbuf_free(pkt_buf);
}
else
{
pbuf_free(pkt_buf);
return;
}
}
/**
* @brief processes tftp read operation
* @param upcb: pointer on udp pcb
* @param to: pointer on remote IP address
* @param to_port: pointer on remote udp port
* @param FileName: pointer on filename to be read
* @retval error code
*/
int tftp_process_read(struct udp_pcb *upcb, const ip_addr_t *to, unsigned short to_port, char* FileName)
{
tftp_connection_args *args = NULL;
/* If Could not open the file which will be transmitted */
if (f_open(&file_SD, (const TCHAR*)FileName, FA_READ) != FR_OK)
{
tftp_send_error_message(upcb, to, to_port, TFTP_ERR_FILE_NOT_FOUND);
tftp_cleanup_rd(upcb, args);
return 0;
}
args = mem_malloc(sizeof *args);
/* If we aren't able to allocate memory for a "tftp_connection_args" */
if (!args)
{
/* unable to allocate memory for tftp args */
tftp_send_error_message(upcb, to, to_port, TFTP_ERR_NOTDEFINED);
/* no need to use tftp_cleanup_rd because no "tftp_connection_args" struct has been malloc'd */
tftp_cleanup_rd(upcb, args);
return 0;
}
/* initialize connection structure */
args->op = TFTP_RRQ;
args->to_ip.addr = to->addr;
args->to_port = to_port;
args->block = 1; /* block number starts at 1 (not 0) according to RFC1350 */
args->tot_bytes = 0;
/* set callback for receives on this UDP PCB */
udp_recv(upcb, rrq_recv_callback, args);
/* initiate the transaction by sending the first block of data,
further blocks will be sent when ACKs are received */
tftp_send_next_block(upcb, args, to, to_port);
return 1;
}
/**
* @brief processes tftp write operation
* @param upcb: pointer on upd pcb
* @param to: pointer on remote IP address
* @param to_port: pointer on remote udp port
* @param FileName: pointer on filename to be written
* @retval error code
*/
int tftp_process_write(struct udp_pcb *upcb, const ip_addr_t *to, unsigned short to_port, char *FileName)
{
tftp_connection_args *args = NULL;
/* Can not create file */
if (f_open(&file_CR, (const TCHAR*)FileName, FA_CREATE_ALWAYS|FA_WRITE) != FR_OK)
{
tftp_send_error_message(upcb, to, to_port, TFTP_ERR_NOTDEFINED);
tftp_cleanup_wr(upcb, args);
return 0;
}
args = mem_malloc(sizeof *args);
if (!args)
{
tftp_send_error_message(upcb, to, to_port, TFTP_ERR_NOTDEFINED);
tftp_cleanup_wr(upcb, args);
return 0;
}
args->op = TFTP_WRQ;
args->to_ip.addr = to->addr;
args->to_port = to_port;
/* the block # used as a positive response to a WRQ is _always_ 0!!! (see RFC1350) */
args->block = 0;
args->tot_bytes = 0;
/* set callback for receives on this UDP PCB */
udp_recv(upcb, wrq_recv_callback, args);
/* initiate the write transaction by sending the first ack */
tftp_send_ack_packet(upcb, to, to_port, args->block);
return 0;
}
/**
* @brief processes the tftp request on port 69
* @param pkt_buf: pointer on received pbuf
* @param ip_addr: pointer on source IP address
* @param port: pointer on source udp port
* @retval None
*/
void process_tftp_request(struct pbuf *pkt_buf, const ip_addr_t *addr, u16_t port)
{
tftp_opcode op = tftp_decode_op(pkt_buf->payload);
char FileName[30];
struct udp_pcb *upcb;
err_t err;
/* create new UDP PCB structure */
upcb = udp_new();
if (!upcb)
{
/* Error creating PCB. Out of Memory */
return;
}
/* bind to port 0 to receive next available free port */
/* NOTE: This is how TFTP works. There is a UDP PCB for the standard port
* 69 which al transactions begin communication on, however all subsequent
* transactions for a given "stream" occur on another port! */
err = udp_bind(upcb, IP_ADDR_ANY, 0);
if (err != ERR_OK)
{
/* Unable to bind to port */
return;
}
switch (op)
{
case TFTP_RRQ:/* TFTP RRQ (read request) */
{
/* Read the name of the file asked by the client to be sent from the SD card */
tftp_extract_filename(FileName, pkt_buf->payload);
/* Could not open filesystem */
if(f_mount(&filesystem, (TCHAR const*)"", 0) != FR_OK)
{
return;
}
/* Could not open the selected directory */
if (f_opendir(&dir_1, "/") != FR_OK)
{
return;
}
/* Start the TFTP read mode*/
tftp_process_read(upcb, addr, port, FileName);
break;
}
case TFTP_WRQ: /* TFTP WRQ (write request) */
{
/* Read the name of the file asked by the client to be received and written in the SD card */
tftp_extract_filename(FileName, pkt_buf->payload);
/* Could not open filesystem */
if(f_mount(&filesystem, (TCHAR const*)"", 0) != FR_OK)
{
return;
}
/* If Could not open the selected directory */
if (f_opendir(&dir_2, "/") != FR_OK)
{
return;
}
/* Start the TFTP write mode*/
tftp_process_write(upcb, addr, port, FileName);
break;
}
default: /* TFTP unknown request op */
/* send generic access violation message */
tftp_send_error_message(upcb, addr, port, TFTP_ERR_ACCESS_VIOLATION);
udp_remove(upcb);
break;
}
}
/**
* @brief tftp receive callback on port 69
* @param arg: pointer on argument passed to callback (not used here)
* @param upcb: pointer on udp pcb
* @param pkt_buf: pointer on received pbuf
* @param ip_addr: pointer on source IP address
* @param port: pointer on source udp port
* @retval None
*/
void recv_callback_tftp(void *arg, struct udp_pcb *upcb, struct pbuf *pkt_buf,
const ip_addr_t *addr, u16_t port)
{
/* process new connection request */
process_tftp_request(pkt_buf, addr, port);
/* free pbuf */
pbuf_free(pkt_buf);
}
/**
* @brief Initializes the udp pcb for TFTP
* @param None
* @retval None
*/
void tftpd_init(void)
{
err_t err;
unsigned port = 69;
/* create a new UDP PCB structure */
UDPpcb = udp_new();
if (UDPpcb)
{
/* Bind this PCB to port 69 */
err = udp_bind(UDPpcb, IP_ADDR_ANY, port);
if (err == ERR_OK)
{
/* TFTP server start */
udp_recv(UDPpcb, recv_callback_tftp, NULL);
}
}
}