ffmap-backend/ffmap/inputs/batadv.py

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import subprocess
import json
class Input:
"""Fill the NodeDB with links from batadv-vis.
The links are added as lists containing the neighboring nodes, not
only their identifiers! Mind this when exporting the database, as
it probably leads to recursion.
"""
def __init__(self, mesh_interface="bat0"):
self.mesh_interface = mesh_interface
@staticmethod
def _is_similar_mac(a, b):
"""Determine if two MAC addresses are similar."""
if a == b:
return True
# Split the address into bytes
try:
mac_a = list(int(i, 16) for i in a.split(":"))
mac_b = list(int(i, 16) for i in b.split(":"))
except ValueError:
return False
# Second and third byte musn't differ
if mac_a[1] != mac_b[1] or mac_a[2] != mac_b[2]:
return False
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# First byte must only differ in bits 2 and 3
if mac_a[0] | 6 != mac_b[0] | 6:
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return False
# Count differing bytes after the third
c = [x for x in zip(mac_a[3:], mac_b[3:]) if x[0] != x[1]]
# No more than two additional bytes must differ
if len(c) > 2:
return False
# If no more bytes differ, they are very similar
if len(c) == 0:
return True
# If the sum of absolute differences isn't greater than 2, they
# are pretty similar
delta = sum(abs(i[0] - i[1]) for i in c)
return delta < 2
def get_data(self, nodedb):
"""Add data from batadv-vis to the supplied nodedb"""
output = subprocess.check_output([
"batadv-vis",
"-i", str(self.mesh_interface),
"-f", "jsondoc",
])
data = json.loads(output.decode("utf-8"))
# First pass
for node in data["vis"]:
# Determine possible other MAC addresses of this node by
# comparing all its client's MAC addresses to its primary
# MAC address. If they are similar, it probably is another
# address of the node itself! If it isn't, it is a real
# client.
node['aliases'] = [node["primary"]]
if 'secondary' in node:
node['aliases'].extend(node['secondary'])
real_clients = []
for mac in node["clients"]:
if self._is_similar_mac(mac, node["primary"]):
node['aliases'].append(mac)
else:
real_clients.append(mac)
node['clients'] = real_clients
# Add nodes and aliases without any information at first.
# This way, we can later link the objects themselves.
nodedb.add_or_update(node['aliases'])
# Second pass
for node in data["vis"]:
# We only need the primary address now, all aliases are
# already present in the database. Furthermore, we can be
# sure that all neighbors are in the database as well. If
# a neighbor isn't added already, we simply ignore it.
nodedb.add_or_update(
[node["primary"]],
{
"clients": node["clients"],
"neighbors": [
{
"metric": neighbor['metric'],
"neighbor": nodedb[neighbor['neighbor']],
} for neighbor in node["neighbors"]
if neighbor['neighbor'] in nodedb
]
}
)