mirror of
https://github.com/Blockstream/satellite-api.git
synced 2025-03-12 10:30:09 +01:00
9d421771e7
- Preserve the SQLite database and use SQLAlchemy to wrap db interactions. - Use Alembic for database migrations. - Organize all the python modules on the new server/ directory. - Use pytest for unit tests and organize test modules at server/tests/.
41 lines
1.3 KiB
Python
41 lines
1.3 KiB
Python
from math import ceil
|
|
from constants import MIN_BID, MIN_PER_BYTE_BID
|
|
|
|
ETH_MTU = 1500
|
|
UDP_IP_HEADER = 20 + 8
|
|
BLOCKSAT_HEADER = 8
|
|
MPE_HEADER = 16
|
|
MAX_BLOCKSAT_PAYLOAD = ETH_MTU - (UDP_IP_HEADER + BLOCKSAT_HEADER)
|
|
|
|
|
|
def calc_ota_msg_len(msg_len):
|
|
"""Compute the number of bytes sent over-the-air (OTA) for an API message
|
|
|
|
API messages are carried by Blocksat Packets, sent in the payload of UDP
|
|
datagrams over IPv4, with a layer-2 MTU of 1500 bytes, and, ultimately,
|
|
transported over MPE. If the message size is such that the UDP/IPv4 packet
|
|
exceeds the layer-2 MTU, fragmentation is not handled at the IP level but
|
|
instead at application layer, i.e., at the Blocksat Packet protocol level.
|
|
|
|
Args:
|
|
msg_len : Length of the API message to be transmitted
|
|
|
|
"""
|
|
# Is it going to be fragmented?
|
|
n_frags = ceil(msg_len / MAX_BLOCKSAT_PAYLOAD)
|
|
|
|
# Including all fragments, considering the Blocksat + UDP + IPv4 + MPE
|
|
# layers, the total overhead becomes:
|
|
total_overhead = (MPE_HEADER + UDP_IP_HEADER + BLOCKSAT_HEADER) * n_frags
|
|
|
|
return total_overhead + msg_len
|
|
|
|
|
|
def get_min_bid(data_len):
|
|
ota_msg_len = calc_ota_msg_len(data_len)
|
|
return max(ceil(ota_msg_len * MIN_PER_BYTE_BID), MIN_BID)
|
|
|
|
|
|
def validate_bid(data_len, bid):
|
|
min_bid = get_min_bid(data_len)
|
|
return bid >= min_bid
|