Commit 75c38a2c authored by Roger Dingledine's avatar Roger Dingledine
Browse files

Bridges now behave like clients with respect to time intervals for

downloading new consensus documents. Bridge users now wait until
the end of the interval, so their bridge will be sure to have a
new consensus document.


svn:r12696
parent b2779545
......@@ -17,6 +17,12 @@ Changes in version 0.2.0.13-alpha - 2007-12-??
- Stop being so aggressive about fetching v2 dir info if your
DirPort is on but your ORPort is off.
o Major features:
- Bridges now behave like clients with respect to time intervals for
downloading new consensus documents. Bridge users now wait until
the end of the interval, so their bridge will be sure to have a
new consensus document.
o Minor bugfixes:
- The fix in 0.2.0.12-alpha cleared the "hsdir" flag in v3 network
consensus documents when there are too many relays at a single
......
......@@ -24,11 +24,13 @@ Status: Open
1.1. PublishServerDescriptor
To configure your relay to be a bridge relay, just add
BridgeRelay 1
PublishServerDescriptor bridge
to your torrc. This will cause your relay to publish its descriptor
to the bridge authorities rather than to the default authorities.
Alternatively, you can say
BridgeRelay 1
PublishServerDescriptor 0
which will cause your relay to not publish anywhere. This could be
useful for private bridges.
......@@ -40,28 +42,17 @@ Status: Open
can supply their bridge users with cached copies of all the various
Tor network information.
Right now (0.2.0.11-alpha) we require that bridges turn their DirPort on
-- which means both that we answer BEGIN_DIR requests and that we fetch
and cache directory information in an aggressive way like other servers.
But:
a) we don't enforce that DirPort is on, since it's not clear how to
detect if the user meant to be a bridge. So it's easy to set up a bridge
relay that silently refuses BEGIN_DIR requests and is thus useless.
b) We don't actually care if they have an open or reachable DirPort. So
at some point we should separate having an open DirPort from answering
directory questions. Which leads to:
c) We need to investigate if there are any anonymity worries with
answering BEGIN_DIR requests when our DirPort is off. If there aren't,
we should drop the DirPort requirement.
I claim that we don't open any new attacks by answering BEGIN_DIR
questions when DirPort is off: it's still a fine question to ask what
partitioning attacks there are when you can query a Tor client about
its current directory opinions, but these attacks already exist when
DirPort is on.
We need to answer this issue in 0.2.0.x.
As for Tor 0.2.0.13-alpha, bridges will answer begin_dir questions
(and cache dir info they see so the answers will be more useful)
whether their DirPort is enabled or not. (After all, we don't care if
they have an open or reachable DirPort to answer begin_dir questions.)
We need to investigate if there are any anonymity worries with answering
BEGIN_DIR requests when our DirPort is off. I claim that we don't open
any new attacks: it's still a fine question to ask what partitioning
attacks there are when you can query a Tor client about its current
directory opinions, but these attacks already exist when DirPort is on.
We should investigate this in 0.2.1.x.
1.3. Exit policy
......
......@@ -1096,8 +1096,11 @@ dirserv_dump_directory_to_string(char **dir_out,
int
directory_fetches_from_authorities(or_options_t *options)
{
/* XXX if options->FetchDirInfoEagerly, return 1 */
if (options->DirPort == 0)
return 0;
if (options->BridgeRelay == 1)
return 0;
/* XXX if dirport not advertised, return 0 too */
if (!server_mode(options))
return 0;
......
......@@ -1058,12 +1058,21 @@ update_consensus_networkstatus_fetch_time(time_t now)
/* But only in the first half-interval after that. */
dl_interval = interval/2;
} else {
/* Give all the caches enough time to download the consensus.*/
/* We're an ordinary client or a bridge. Give all the caches enough
* time to download the consensus. */
start = c->fresh_until + (interval*3)/4;
/* But download the next one before this one is expired. */
/* But download the next one well before this one is expired. */
dl_interval = ((c->valid_until - start) * 7 )/ 8;
/* XXX020 do something different if
* directory_fetches_dir_info_like_bridge_user() */
/* If we're a bridge user, make use of the numbers we just computed
* to choose the rest of the interval *after* them. */
if (directory_fetches_dir_info_like_bridge_user(options)) {
/* Give all the *clients* enough time to download the consensus. */
start = start + dl_interval + CONSENSUS_MIN_SECONDS_BEFORE_CACHING;
/* But try to get it before ours actually expires. */
dl_interval = (c->valid_until - start) -
CONSENSUS_MIN_SECONDS_BEFORE_CACHING;
}
}
if (dl_interval < 1)
dl_interval = 1;
......
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