Macintosh-SW/NetBoot
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Ignore client's buggy bitmap

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The client sends the wrong "missing block bitmap" when the image is
small. I think that it is best to ignore the bitmap and retransmit *all*
blocks when *any* request is received. Also introduce arbitrary block
sizes.
This commit is contained in:
Elliot Nunn 2021-04-12 19:01:00 +08:00
parent 6cc36e1561
commit a84a379886
2 changed files with 12 additions and 9 deletions
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19
ChainBoot.py
View File

@ -17,6 +17,8 @@ from snefru_hash import append_snefru
ATBOOT_BLOCK_SIZE = 256 # must be a multiple of 64 or snefru will choke
UNRELIABILITY_PERCENT = 0
def failchance():
return (random.random() < UNRELIABILITY_PERCENT/100)
@ -37,9 +39,11 @@ for img2name in image2:
# image += struct.pack('>LB', len(img2)//512, len(img2name)) + img2name
while len(image) % 2: image += b'\0'
image += bytes(5)
while len(image) < 8 * 512: image += b'?'
# image += b'Elliot'*10000 # padding, too much!
# Constraint: client crashes when there is only one block
while len(image) <= ATBOOT_BLOCK_SIZE: image += b'\0'
# Constraint: client expects hash in the last 64 bytes of the last block
while len(image) % ATBOOT_BLOCK_SIZE != ATBOOT_BLOCK_SIZE - 64: image += b'\0'
image = append_snefru(image)
writable_image = bytearray(open('A608.dsk', 'rb').read())
@ -248,7 +252,7 @@ while 1:
dest_node=llap_src_node, dest_socket=ddp_src_socket,
src_node=99, src_socket=99,
proto_type=10,
data=struct.pack('>BBHLHHhL', 2, 1, boot_machine_id, boot_timestamp, 512, 0, 0, len(image) // 512).ljust(586, b'\0')
data=struct.pack('>BBHLHHhL', 2, 1, boot_machine_id, boot_timestamp, ATBOOT_BLOCK_SIZE, 0, 0, len(image) // ATBOOT_BLOCK_SIZE).ljust(586, b'\0')
))
elif boot_type == 3:
@ -272,8 +276,9 @@ while 1:
# Okay, pretty much just send the bits that were requested!
print('Sending blocks')
for blocknum in range(len(image) // 512):
if len(data) > blocknum // 8 and (data[blocknum // 8] >> (blocknum % 8)) & 1:
for blocknum in range(len(image) // ATBOOT_BLOCK_SIZE):
# if len(data) > blocknum // 8 and (data[blocknum // 8] >> (blocknum % 8)) & 1:
if 1:
# typedef struct {
# unsigned char packetType; /* The command number */
# unsigned char packetVersion; /* Protocol version number */
@ -287,7 +292,7 @@ while 1:
dest_node=llap_src_node, dest_socket=ddp_src_socket,
src_node=99, src_socket=99,
proto_type=10,
data=struct.pack('>BBHH', 4, 1, boot_image_id, blocknum) + image[blocknum*512:blocknum*512+512]
data=struct.pack('>BBHH', 4, 1, boot_image_id, blocknum) + image[blocknum*ATBOOT_BLOCK_SIZE:blocknum*ATBOOT_BLOCK_SIZE+ATBOOT_BLOCK_SIZE]
))
# time.sleep(0.5)

2
ChainLoader.a
View File

@ -732,5 +732,3 @@ gUserRec ; append user record here later on, no need to waste space on zeros
DrvrEnd
CodeEnd
align 12 ; work around unfortunate .ATBOOT bug