EPICS CAS request errors "missaligned protocol rejected" packet reconstruction by way of caproto

misaligned.py

lines = '''CAS: request from 172.23.120.148:38554 => CAS: Missaligned protocol rejected
CAS: Request from 172.23.120.148:38554 => cmmd=0 cid=0x9 type=32769 count=1 postsize=22
CAS: Request from 172.23.120.148:38554 =>   available=0x6765744c        N=0 paddr=0x7fad1800d5f0
CAS: forcing disconnect from 172.23.120.148:38554
CAS: request from 172.23.120.148:38560 => CAS: Client version too old
CAS: Request from 172.23.120.148:38560 => cmmd=18245 cid=0x54502f31 type=12064 count=18516 postsize=21536
CAS: Request from 172.23.120.148:38560 =>   available=0x2e300d0a        N=0 paddr=(nil)
CAS: request from 172.23.120.148:41978 => CAS: Client version too old
CAS: Request from 172.23.120.148:41978 => cmmd=768 cid=0x1 type=3808 count=0 postsize=19
CAS: Request from 172.23.120.148:41978 =>   available=0x80000   N=0 paddr=0x7fad1800d930
CAS: request from 172.23.120.148:42174 => CAS: Client version too old
CAS: Request from 172.23.120.148:42174 => cmmd=769 cid=0x3b0000 type=7 count=0 postsize=2560
CAS: Request from 172.23.120.148:42174 =>   available=0x0       N=0 paddr=(nil)
CAS: request from 172.23.120.148:45908 => CAS: Client version too old
CAS: Request from 172.23.120.148:45908 => cmmd=18245 cid=0x54502f31 type=12064 count=18516 postsize=21536
CAS: Request from 172.23.120.148:45908 =>   available=0x2e310d0a        N=0 paddr=(nil)
CAS: request from 172.23.120.148:47586 => CAS: Client version too old
CAS: Request from 172.23.120.148:47586 => cmmd=18245 cid=0x54502f31 type=12064 count=18516 postsize=21536
CAS: Request from 172.23.120.148:47586 =>   available=0x2e310d0a        N=0 paddr=(nil)
CAS: request from 172.23.120.148:51592 => CAS: Client version too old
CAS: Request from 172.23.120.148:51592 => cmmd=18245 cid=0x54502f31 type=12064 count=18516 postsize=21536
CAS: Request from 172.23.120.148:51592 =>   available=0x2e310d0a        N=0 paddr=(nil)
'''.strip().splitlines()

first = [
    line for line in lines if 'cmmd' in line
]

def parse(line):
    res = {}
    for item in line.split(' '):
        if '=' in item:
            key, value = item.split('=')
            if key in ('paddr', ):
                continue
            if value.startswith('0x'):
                value = int(value, 16)
            else:
                value = int(value)
            res[key] = value
    return res

items = [
    parse(line.split('=> ')[1] + lines[lines.index(line) + 1].split('=> ')[1])
    for line in first
]

headers = [
    MessageHeader(
        command=d['cmmd'],
        parameter1=d['cid'],
        data_type=d['type'],
        data_count=d['count'],
        payload_size=d['postsize'],
        parameter2=d['available']
    )
    for d in items
]

print([bytes(header) for header in headers])