commit 57ed21a26d440d32e01924cbc027d97665fe8dbc Author: Damian Johnson atagar@torproject.org Date: Tue Apr 10 09:03:39 2012 -0700

Server descriptor reformatting

Cleaning up the recent changes to split apart relay and bridge descriptors, dropping an unnecessary parser class and rearranging things to be more readable. --- stem/descriptor/server_descriptor.py | 204 +++++++++++++++++++--------------- 1 files changed, 112 insertions(+), 92 deletions(-)

diff --git a/stem/descriptor/server_descriptor.py b/stem/descriptor/server_descriptor.py index a0f688c..8548cf2 100644 --- a/stem/descriptor/server_descriptor.py +++ b/stem/descriptor/server_descriptor.py @@ -238,31 +238,28 @@ class ServerDescriptorV3(stem.descriptor.Descriptor): self.read_history = None self.write_history = None self.eventdns = True + self._unrecognized_lines = [] + + self._annotation_lines = annotations if annotations else [] + self._annotation_dict = None # cached breakdown of key/value mappings

# TODO: Until we have a proper ExitPolicy class this is just a list of the # exit policy strings...

self.exit_policy = []

- self._unrecognized_lines = [] + # A descriptor contains a series of 'keyword lines' which are simply a + # keyword followed by an optional value. Lines can also be followed by a + # signature block. + # + # We care about the ordering of 'accept' and 'reject' entries because this + # influences the resulting exit policy, but for everything else the order + # does not matter so breaking it into key / value pairs.

- if annotations: - self._annotation_lines = annotations - self._annotation_dict = {} - - for line in annotations: - if " " in line: - key, value = line.split(" ", 1) - self._annotation_dict[key] = value - else: self._annotation_dict[line] = None - else: - self._annotation_lines = [] - self._annotation_dict = {} - - contents = _DescriptorContents(raw_contents, validate) - self.exit_policy = contents.exit_policy - self._parse(contents.entries, validate) - if validate: self._check_constraints(contents) + entries, first_keyword, last_keyword, self.exit_policy = \ + _get_descriptor_components(raw_contents, validate) + self._parse(entries, validate) + if validate: self._check_constraints(entries, first_keyword, last_keyword)

def get_unrecognized_lines(self): return list(self._unrecognized_lines) @@ -279,6 +276,17 @@ class ServerDescriptorV3(stem.descriptor.Descriptor): dict with the key/value pairs in our annotations """

+ if self._annotation_dict == None: + annotation_dict = {} + + for line in self._annotation_lines: + if " " in line: + key, value = line.split(" ", 1) + annotation_dict[key] = value + else: annotation_dict[line] = None + + self._annotation_dict = annotation_dict + return self._annotation_dict

def get_annotation_lines(self): @@ -306,7 +314,6 @@ class ServerDescriptorV3(stem.descriptor.Descriptor): ValueError if an error occures in validation """

- for keyword, values in entries.items(): # most just work with the first (and only) value value, block_contents = values[0] @@ -460,13 +467,15 @@ class ServerDescriptorV3(stem.descriptor.Descriptor): else: self._unrecognized_lines.append(line)

- def _check_constraints(self, contents): + def _check_constraints(self, entries, first_keyword, last_keyword): """ Does a basic check that the entries conform to this descriptor type's constraints.

Arguments: - contents (_DescriptorContents) - contents to be validated + entries (dict) - keyword => (value, pgp key) entries + first_keyword (str) - keyword of the first line + last_keyword (str) - keyword of the last line

Raises: ValueError if an issue arises in validation @@ -475,21 +484,21 @@ class ServerDescriptorV3(stem.descriptor.Descriptor): required_fields = self._required_fields() if required_fields: for keyword in required_fields: - if not keyword in contents.entries: + if not keyword in entries: raise ValueError("Descriptor must have a '%s' entry" % keyword)

single_fields = self._single_fields() if single_fields: for keyword in self._single_fields(): - if keyword in contents.entries and len(contents.entries[keyword]) > 1: + if keyword in entries and len(entries[keyword]) > 1: raise ValueError("The '%s' entry can only appear once in a descriptor" % keyword)

- first_keyword = self._first_keyword() - if first_keyword and not contents.first_keyword == first_keyword: + expected_first_keyword = self._first_keyword() + if expected_first_keyword and not first_keyword == expected_first_keyword: raise ValueError("Descriptor must start with a '%s' entry" % first_keyword)

- last_keyword = self._last_keyword() - if last_keyword and not contents.last_keyword == self._last_keyword(): + expected_last_keyword = self._last_keyword() + if expected_last_keyword and not last_keyword == expected_last_keyword: raise ValueError("Descriptor must end with a '%s' entry" % last_keyword)

if not self.exit_policy: @@ -581,23 +590,28 @@ class BridgeDescriptorV3(ServerDescriptorV3):

def _parse(self, entries, validate): ServerDescriptorV3._parse(self, entries, validate) + if validate: self._check_scrubbing() + + def _check_scrubbing(self): + """ + Checks that our attributes have been scrubbed in accordance with the bridge + descriptor specification. + """

- if validate: - # checks that we properly scrubbed fields - if self.nickname != "Unnamed": - raise ValueError("Router line's nickname should be scrubbed to be 'Unnamed': %s" % self.nickname) - elif not self.address.startswith("10."): - raise ValueError("Router line's address should be scrubbed to be '10.x.x.x': %s" % self.address) - elif self.contact and self.contact != "somebody": - raise ValueError("Contact line should be scrubbed to be 'somebody', but instead had '%s'" % self.contact) - - for line in self.get_unrecognized_lines(): - if line.startswith("onion-key "): - raise ValueError("Bridge descriptors should have their onion-key scrubbed: %s" % self.onion_key) - elif line.startswith("signing-key "): - raise ValueError("Bridge descriptors should have their signing-key scrubbed: %s" % self.signing_key) - elif line.startswith("router-signature "): - raise ValueError("Bridge descriptors should have their signature scrubbed: %s" % self.signature) + if self.nickname != "Unnamed": + raise ValueError("Router line's nickname should be scrubbed to be 'Unnamed': %s" % self.nickname) + elif not self.address.startswith("10."): + raise ValueError("Router line's address should be scrubbed to be '10.x.x.x': %s" % self.address) + elif self.contact and self.contact != "somebody": + raise ValueError("Contact line should be scrubbed to be 'somebody', but instead had '%s'" % self.contact) + + for line in self.get_unrecognized_lines(): + if line.startswith("onion-key "): + raise ValueError("Bridge descriptors should have their onion-key scrubbed: %s" % line) + elif line.startswith("signing-key "): + raise ValueError("Bridge descriptors should have their signing-key scrubbed: %s" % line) + elif line.startswith("router-signature "): + raise ValueError("Bridge descriptors should have their signature scrubbed: %s" % line)

def _required_fields(self): # bridge required fields are the same as a relay descriptor, minus items @@ -617,10 +631,9 @@ class BridgeDescriptorV3(ServerDescriptorV3): def _first_keyword(self): return "router"

-class _DescriptorContents: +def _get_descriptor_components(raw_contents, validate): """ - Initial breakup of the server descriptor contents to make parsing easier - later. + Initial breakup of the server descriptor contents to make parsing easier.

A descriptor contains a series of 'keyword lines' which are simply a keyword followed by an optional value. Lines can also be followed by a signature @@ -630,55 +643,62 @@ class _DescriptorContents: influences the resulting exit policy, but for everything else the order does not matter so breaking it into key / value pairs.

- Attributes: - entries (dict) - keyword => (value, pgp key) entries - first_keyword (str) - keyword of the first line - last_keyword (str) - keyword of the last line - exit_policy (list) - lines containing the exit policy + Arguments: + raw_contents (str) - descriptor content provided by the relay + validate (bool) - checks the validity of the descriptor's content if + True, skips these checks otherwise + + Returns: + tuple with the following attributes... + entries (dict) - keyword => (value, pgp key) entries + first_keyword (str) - keyword of the first line + last_keyword (str) - keyword of the last line + exit_policy (list) - lines containing the exit policy """

- def __init__(self, raw_contents, validate): - self.entries = {} - self.first_keyword = None - self.last_keyword = None - self.exit_policy = [] - remaining_lines = raw_contents.split("\n") + entries = {} + first_keyword = None + last_keyword = None + exit_policy = [] + remaining_lines = raw_contents.split("\n") + + while remaining_lines: + line = remaining_lines.pop(0)

- while remaining_lines: - line = remaining_lines.pop(0) - - # last line can be empty - if not line and not remaining_lines: continue - - # Some lines have an 'opt ' for backward compatability. They should be - # ignored. This prefix is being removed in... - # https://trac.torproject.org/projects/tor/ticket/5124 - - if line.startswith("opt "): line = line[4:] - - line_match = KEYWORD_LINE.match(line) - - if not line_match: - if not validate: continue - raise ValueError("Line contains invalid characters: %s" % line) - - keyword, value = line_match.groups() - - if not self.first_keyword: self.first_keyword = keyword - self.last_keyword = keyword - - try: - block_contents = _get_pseudo_pgp_block(remaining_lines) - except ValueError, exc: - if not validate: continue - raise exc - - if keyword in ("accept", "reject"): - self.exit_policy.append("%s %s" % (keyword, value)) - elif keyword in self.entries: - self.entries[keyword].append((value, block_contents)) - else: - self.entries[keyword] = [(value, block_contents)] + # last line can be empty + if not line and not remaining_lines: continue + + # Some lines have an 'opt ' for backward compatability. They should be + # ignored. This prefix is being removed in... + # https://trac.torproject.org/projects/tor/ticket/5124 + + if line.startswith("opt "): line = line[4:] + + line_match = KEYWORD_LINE.match(line) + + if not line_match: + if not validate: continue + raise ValueError("Line contains invalid characters: %s" % line) + + keyword, value = line_match.groups() + + if not first_keyword: first_keyword = keyword + last_keyword = keyword + + try: + block_contents = _get_pseudo_pgp_block(remaining_lines) + except ValueError, exc: + if not validate: continue + raise exc + + if keyword in ("accept", "reject"): + exit_policy.append("%s %s" % (keyword, value)) + elif keyword in entries: + entries[keyword].append((value, block_contents)) + else: + entries[keyword] = [(value, block_contents)] + + return entries, first_keyword, last_keyword, exit_policy

def _get_pseudo_pgp_block(remaining_contents): """