def nlmsg_attrlen(nlh, hdrlen):
"""Length of attributes data.
https://github.com/thom311/libnl/blob/libnl3_2_25/lib/msg.c#L154
nlh -- Netlink message header (nlmsghdr class instance).
hdrlen -- length of family specific header (integer).
Returns:
Integer.
"""
return max(nlmsg_len(nlh) - libnl.linux_private.netlink.NLMSG_ALIGN(hdrlen), 0)
def dump_error_msg(msg, ofd=_LOGGER.debug):
"""https://github.com/thom311/libnl/blob/libnl3_2_25/lib/msg.c#L908.
Positional arguments:
msg -- message to print (nl_msg class instance).
Keyword arguments:
ofd -- function to call with arguments similar to `logging.debug`.
"""
hdr = nlmsg_hdr(msg)
err = libnl.linux_private.netlink.nlmsgerr(nlmsg_data(hdr))
ofd(' [ERRORMSG] %d octets', err.SIZEOF)
if nlmsg_len(hdr) >= err.SIZEOF:
ofd(' .error = %d "%s"', err.error, os.strerror(-err.error))
ofd(' [ORIGINAL MESSAGE] %d octets', hdr.SIZEOF)
errmsg = nlmsg_inherit(err.msg)
print_hdr(ofd, errmsg)
def nl_msg_dump(msg, ofd=_LOGGER.debug):
"""Dump message in human readable format to callable.
https://github.com/thom311/libnl/blob/libnl3_2_25/lib/msg.c#L970
Positional arguments:
msg -- message to print (nl_msg class instance).
Keyword arguments:
ofd -- function to call with arguments similar to `logging.debug`.
"""
hdr = nlmsg_hdr(msg)
ofd('-------------------------- BEGIN NETLINK MESSAGE ---------------------------')
ofd(' [NETLINK HEADER] %d octets', hdr.SIZEOF)
print_hdr(ofd, msg)
if hdr.nlmsg_type == libnl.linux_private.netlink.NLMSG_ERROR:
dump_error_msg(msg, ofd)
elif nlmsg_len(hdr) > 0:
print_msg(msg, ofd, hdr)
ofd('--------------------------- END NETLINK MESSAGE ---------------------------')
def print_msg(msg, ofd, hdr):
"""https://github.com/thom311/libnl/blob/libnl3_2_25/lib/msg.c#L929.
Positional arguments:
msg -- Netlink message (nl_msg class instance).
ofd -- function to call with arguments similar to `logging.debug`.
hdr -- Netlink message header (nlmsghdr class instance).
"""
payloadlen = c_int(nlmsg_len(hdr))
attrlen = 0
data = nlmsg_data(hdr)
ops = nl_cache_ops_associate_safe(msg.nm_protocol, hdr.nlmsg_type)
if ops:
attrlen = nlmsg_attrlen(hdr, ops.co_hdrsize)
payloadlen.value -= attrlen
if msg.nm_protocol == libnl.linux_private.netlink.NETLINK_GENERIC:
data = print_genl_msg(msg, ofd, hdr, ops, payloadlen)
if payloadlen.value:
ofd(' [PAYLOAD] %d octets', payloadlen.value)
dump_hex(ofd, data, payloadlen.value, 0)
if attrlen:
attrs = nlmsg_attrdata(hdr, ops.co_hdrsize)
attrlen = nlmsg_attrlen(hdr, ops.co_hdrsize)
dump_attrs(ofd, attrs, attrlen, 0)