def _register_dissector(self):
"""Add code for registering the dissector in the dissector table."""
# Dissector message id, which maps to name
if self.id is None:
message_ids = ['nil']
else:
message_ids = self.id
# Dissector Sizes and platforms
sizes = {i.platform.flag: i.size for i in self.dissectors.values()}
sizes = create_lua_valuestring(sizes, wrap=False)
data = []
for id in message_ids:
data.append('{func}({var}, "{name}", {id}, {sizes})'.format(
func=self.REGISTER_FUNC, var=self.var,
name=self.name, id=id, sizes=sizes))
data.extend(['', ''])
return '\n'.join(i for i in data if i is not None)
def _dissector_func(self):
"""Add the code for the dissector function for the protocol."""
data = ['-- Dissector function for: %s' % self.name]
def retrieve_pinfo():
data.append('\tif pinfo.private.field_name then')
t = '\t\tsubtree:set_text(pinfo.private.field_name .. ": {name}")'
data.append(t.format(name=child.name))
data.append('\t\tpinfo.private.field_name = nil\n\telse')
t = '\t\tpinfo.cols.info:append("({desc})")'
data.append(t.format(desc=self.description))
data.append('\tend')
# Dissector function
func_diss = 'function {var}.dissector(buffer, pinfo, tree)'
data.append(func_diss.format(var=self.var))
# Retrieve flag value from private info table
flag_var = create_lua_var('flag')
flag = '\tlocal {var} = tonumber(pinfo.private.platform_flag)'
data.append(flag.format(var=flag_var))
# If only 1 or less dissectors, insert dissector code directly
if len(self.dissectors) < 2:
if self.dissectors:
child = list(self.dissectors.values())[0]
sub_tree = '\tlocal subtree = tree:{add}({var}, buffer())'
data.append(sub_tree.format(add=child.add_var, var=self.var))
retrieve_pinfo()
data.append(child.get_code(0))
data.extend(['end', ''])
return '\n'.join(i for i in data if i is not None)
# Get flags and call the platform specific function
table = {}
for child in self.dissectors.values():
child._func_name = create_lua_var(
'%s_%s' % (self.var, child.platform.name))
table[child.platform.flag] = child._func_name
table = create_lua_valuestring(table, wrap=False)
data.append('\tlocal func_mapping = {table}'.format(table=table))
data.append('\tif func_mapping[{var}] then'.format(var=flag_var))
call = '\t\t func_mapping[{var}](buffer, pinfo, tree)'
data.append(call.format(var=flag_var))
data.extend(['\tend', 'end', ''])
# Modify name if sub-dissector
pinfo_func = create_lua_var('%s_pinfo_magic' % self.var)
data.append('-- Function for retrieving parent dissector name')
data.append('function {func}(pinfo, subtree)'.format(func=pinfo_func))
retrieve_pinfo()
data.extend(['end', ''])
# Create dissector function for each dissector
for child in self.dissectors.values():
data.append('-- Dissector function for: %s (platform: %s)' % (
child.name, child.platform.name))
func = 'function {name}(buffer, pinfo, tree)'
data.append(func.format(name=child._func_name))
# Add subtree
sub_tree = '\tlocal subtree = tree:{add}({var}, buffer())'
data.append(sub_tree.format(add=child.add_var, var=self.var))
data.append('\t{func}(pinfo, subtree)'.format(func=pinfo_func))
# Add the actual field code for each field
data.append(child.get_code(0))
data.extend(['end', ''])
return '\n'.join(i for i in data if i is not None)
