Single DA in sandbox vs. PDS_ALLOW_SELF flag
I am running a TOR network simulation in a self-contained sandbox, and only really need a single node to act as Directory Authority. The configuration file looks as follows (the DA's fqdn is da.sandbox.local, and its IP is 126.96.36.199):
common to all nodes:
RunAsDaemon 1 TestingTorNetwork 1 UseDefaultFallbackDirs 0 DataDirectory /var/lib/tor PidFile /var/lib/tor/pid Log info file /var/lib/tor/info.log SafeLogging 0 DirAuthority orport=5000 v3ident=6542F7312EE19D39E9D389CCCB1DDD342A32E94D 188.8.131.52:7000 1B494B7382C8C2D2D13FB0B5175B0B3A14E54D69
additionally, regular onion routers (incl. the DA):
additionally, for the DA only:
DirPort 7000 Address da.sandbox.local OutboundBindAddress da.sandbox.local AuthoritativeDirectory 1 V3AuthoritativeDirectory 1 V3AuthVotingInterval 10 V3AuthVoteDelay 2 V3AuthDistDelay 2
When I start the DA, I get lots of log entries (in /var/lib/tor/info.log) complaining about the absence of any reachable directory servers:
[info] router_pick_dirserver_generic(): No dirservers are reachable. Trying them all again. [info] router_pick_directory_server(): No reachable router entries for dirservers. Trying them all again. [info] directory_pick_generic_dirserver(): No router found for consensus network-status fetch; falling back to dirserver list.
While the single DA eventually appears to work properly, and publishes a consensus file containing itself as a router entry, these warnings keep showing up periodically in the log file on an ongoing basis.
Once the DA publishes its initial one-entry consensus, I can start further ORs which are quickly added to the consensus, and any client nodes are easily able to build circuits and operate correctly in my sandbox network.
In an attempt to silence the DA's dirserver reachability complaints I looked through the TOR sources, and found that a DA's ability to pick itself as its own directory server (in function router_pick_directory_server() in file src/or/routerlist.c) is controlled by the PDS_ALLOW_SELF flag.
This flag was originally introduced in commit 02e7a83f, and also appears in subsequent commits b87a7760, 74c2bff7, and b3a69074. The latter two commits remove code that used to set the flag (haven't spent the time to figure out if this would have helped my single-DA scenario, though).
Currently, there appears to be no code path that sets this flag, and also no way to request it to be set via the command line or configuration file.
Would it make sense to assume the flag is always set (which would always allow a DA to pick itself as its own DA), or rather would it be better to provide some interface (config file entry) that allows setting the flag explicitly (maybe only in testing mode)?