From 3cc27add50efd3c912f33ed42b3f0fab40a64fff Mon Sep 17 00:00:00 2001
From: schneider <schneider@blinkenlichts.net>
Date: Thu, 14 Jul 2011 23:40:03 +0200
Subject: [PATCH] added xxtea encrypted file transfer

---
 firmware/funk/Makefile       |  1 +
 firmware/funk/filetransfer.c | 89 ++++++++++++++++++++++++++++++++++++
 firmware/funk/filetransfer.h | 10 ++++
 firmware/funk/nrf24l01p.h    |  4 ++
 4 files changed, 104 insertions(+)
 create mode 100644 firmware/funk/filetransfer.c
 create mode 100644 firmware/funk/filetransfer.h

diff --git a/firmware/funk/Makefile b/firmware/funk/Makefile
index e44105f..dd2a593 100644
--- a/firmware/funk/Makefile
+++ b/firmware/funk/Makefile
@@ -6,6 +6,7 @@ OBJS =
 
 OBJS += nrf24l01p.o
 OBJS += rftransfer.o
+OBJS += filetransfer.o
 
 LIBNAME=funk
 
diff --git a/firmware/funk/filetransfer.c b/firmware/funk/filetransfer.c
new file mode 100644
index 0000000..5bae5d2
--- /dev/null
+++ b/firmware/funk/filetransfer.c
@@ -0,0 +1,89 @@
+#include <string.h>
+#include "nrf24l01p.h"
+#include "filetransfer.h"
+#include "rftransfer.h"
+#include "basic/xxtea.h"
+#include "filesystem/ff.h"
+
+int filetransfer_send(uint8_t *filename, uint16_t size,
+                uint8_t *mac, uint32_t const k[4])
+{
+    uint8_t buf[MAXSIZE];
+    FIL file;
+    FRESULT res;
+    UINT readbytes;
+
+    if( size > MAXSIZE )
+        return 1;           //File to big
+ 
+    res=f_open(&file, (const char*)filename, FA_OPEN_EXISTING|FA_READ);
+    if( res )
+        return res;
+
+    res = f_read(&file, (char *)buf, size, &readbytes);
+    if( res )
+        return res;
+    if( size != readbytes)
+        return 1;           //Error while reading
+    
+    uint16_t wordcount = (size+3)/4;
+    uint8_t macbuf[5];
+
+    uint8_t metadata[30];
+    if( strlen((char*)filename) < 20 )
+        strcpy((char*)metadata, (char*)filename);
+    else
+        return 1;           //File name too long
+    metadata[20] = size >> 8;
+    metadata[21] = size & 0xFF;
+
+    //nrf_get_tx_max(5,macbuf);
+    nrf_set_tx_mac(5, mac);
+    
+    nrf_snd_pkt_xxtea(30, metadata, k); 
+    xxtea_encode_words((uint32_t *)buf, wordcount, k);
+    rftransfer_send(wordcount*4, buf);
+    nrf_set_tx_mac(5, macbuf);
+    return 0;
+}
+
+int filetransfer_receive(uint8_t *mac, uint32_t const k[4])
+{
+    uint8_t buf[MAXSIZE+1];
+    uint16_t size;
+
+    UINT written = 0;
+    FIL file;
+    FRESULT res;
+    uint8_t macbuf[5];
+    //nrf_get_tx_max(5,macbuf);
+    nrf_set_tx_mac(5, mac);
+
+    uint8_t metadata[30];
+    nrf_rcv_pkt_time_xxtea(1000, 30, metadata, k);
+    metadata[19] = 0; //enforce termination
+    size = (metadata[20] << 8) | metadata[21];
+
+    if( size > MAXSIZE ) return 1; //file to big
+    //if(fileexists(metadata)) return 1;   //file already exists
+    
+    res = f_open(&file, (const char*)metadata, FA_OPEN_ALWAYS|FA_WRITE);
+    if( res )
+        return res;
+    
+    uint16_t wordcount = (size+3)/4;
+    rftransfer_receive(buf, wordcount*4, 1000);
+
+    nrf_set_tx_mac(5, macbuf);
+
+    xxtea_decode_words((uint32_t *)buf, wordcount, k);
+    
+    res = f_write(&file, buf, size, &written);
+    if( res )
+        return res;
+    if( written != size )
+        return 1;           //error while writing
+
+    return 0;
+}
+
diff --git a/firmware/funk/filetransfer.h b/firmware/funk/filetransfer.h
new file mode 100644
index 0000000..d155bfc
--- /dev/null
+++ b/firmware/funk/filetransfer.h
@@ -0,0 +1,10 @@
+#ifndef _FILETRANSFER_H_
+#define _FILETRANSFER_H_
+#include <stdint.h>
+
+#define MAXSIZE 1024
+
+int filetransfer_send(uint8_t *filename, uint16_t size,
+                uint8_t *mac, uint32_t const k[4]);
+int filetransfer_receive(uint8_t *mac, uint32_t const k[4]);
+#endif
diff --git a/firmware/funk/nrf24l01p.h b/firmware/funk/nrf24l01p.h
index ada0fbd..c78c590 100644
--- a/firmware/funk/nrf24l01p.h
+++ b/firmware/funk/nrf24l01p.h
@@ -1,5 +1,6 @@
 #ifndef _NRF24L01P_H
 #define _NRF24L01P_H 1
+#include <stdint.h>
 
 #define MAX_PKT (32-2) // 2 bytes are our CRC
 
@@ -109,7 +110,10 @@
 
 /* exported functions */
 int nrf_rcv_pkt_time(int maxtime, int maxsize, uint8_t * pkt);
+int nrf_rcv_pkt_time_xxtea(int maxtime, int maxsize,
+                                uint8_t * pkt, uint32_t const k[4]);
 char nrf_snd_pkt_crc(int size, uint8_t * pkt);
+char nrf_snd_pkt_xxtea(int size, uint8_t * pkt, uint32_t const k[4]);
 void nrf_init() ;
 
 void nrf_cmd(uint8_t cmd);