From b722280c5ac1b21f0960b069828be5629518085d Mon Sep 17 00:00:00 2001
From: Bobbi Webber-Manners <bmanners@krakenrobotics.com>
Date: Thu, 11 Jun 2020 00:24:27 -0400
Subject: [PATCH] First version of VEServer - alternative server for ADT's
 VEDRIVE.SYSTEM.

---
 veserver.py | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100755 veserver.py

diff --git a/veserver.py b/veserver.py
new file mode 100755
index 0000000..0cc1564
--- /dev/null
+++ b/veserver.py
@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+
+#
+# Bobbi 2020
+#
+# Alternative server for ADTPro's VEDRIVE.SYSTEM
+# Virtual Ethernet Drive for Apple II / ProDOS
+#
+# See https://www.adtpro.com/protocolv1.html
+#
+
+import socket
+
+IP = "::"
+PORT = 6502
+FILE1 = "virtual-1.po"
+FILE2 = "virtual-2.po"
+BLKSZ = 512
+
+packet = 1
+
+# Append byte b to list l
+# Return updated checksum
+def appendbyte(l, b, csin):
+    l.append(b)
+    return csin ^ b
+
+#
+# Read block with date/time update
+#
+def read3(sock, addr, drive, d):
+    global packet
+    l = []
+    appendbyte(l, packet & 0xff, 0)  # Packet number
+    packet += 1
+    cs = appendbyte(l, 0xc5, 0)   # "E"
+    cs = appendbyte(l, d[1], cs)  # 0x03 or 0x05
+    cs = appendbyte(l, d[2], cs)  # Block num LSB
+    cs = appendbyte(l, d[3], cs)  # Block num MSB
+    cs = appendbyte(l, 0, cs)     # TODO: Date/time
+    cs = appendbyte(l, 0, cs)     # TODO: Date/time
+    cs = appendbyte(l, 0, cs)     # TODO: Date/time
+    cs = appendbyte(l, 0, cs)     # TODO: Date/time
+    appendbyte(l, cs, cs)         # Checksum
+
+    blknum = d[2] + 256 * d[3]
+    print('R{0:05d} '.format(blknum), end='', flush=True)
+    b = blknum * BLKSZ
+    if d[1] == 0x03:
+       file = FILE1
+    else:
+       file = FILE2
+    with open(file, 'rb') as f:
+        f.seek(b)
+        block = f.read(BLKSZ)
+
+    cs = 0
+    for i in range (0, BLKSZ):
+        cs = appendbyte(l, block[i], cs)
+    appendbyte(l, cs, cs)
+
+    b = sock.sendto(bytearray(l), addr)
+    #print('Sent {} bytes to {}'.format(b, addr))
+
+#
+# Write block
+#
+def write(sock, addr, drive, d):
+    global packet
+    l = []
+    appendbyte(l, packet & 0xff, 0)  # Packet number
+    packet += 1
+    cs = appendbyte(l, 0xc5, 0)   # "E"
+    cs = appendbyte(l, d[1], cs)  # 0x02 or 0x04
+    cs = appendbyte(l, d[2], cs)  # Block num LSB
+    cs = appendbyte(l, d[3], cs)  # Block num MSB
+    cs = appendbyte(l, d[517], cs)  # Block num MSB
+
+    blknum = d[2] + 256 * d[3]
+    print('W{0:05d} '.format(blknum), end='', flush=True)
+    b = blknum * BLKSZ
+
+    if d[1] == 0x02:
+       file = FILE1
+    else:
+       file = FILE2
+    with open(file, 'r+b') as f:
+        f.seek(b)
+        for i in range (0, BLKSZ):
+            f.write(bytes([d[i+5]]))
+
+    b = sock.sendto(bytearray(l), addr)
+    #print('Sent {} bytes to {}'.format(b, addr))
+
+
+with socket.socket(socket.AF_INET6, socket.SOCK_DGRAM) as s:
+    s.bind((IP, PORT))
+    print("veserver - listening on UDP port ", PORT)
+    while True:
+        data, address = s.recvfrom(1024)
+        #print('Received {} bytes from {}'.format(len(data), address))
+        if (data[0] == 0xc5):
+            if (data[1] == 0x03):
+                read3(s, address, 1, data)
+            elif (data[1] == 0x05):
+                read3(s, address, 2, data)
+            elif (data[1] == 0x02):
+                write(s, address, 1, data)
+            elif (data[1] == 0x04):
+                write(s, address, 2, data)
+