diff options
Diffstat (limited to 'src/core/or/protover.c')
| -rw-r--r-- | src/core/or/protover.c | 107 |
1 files changed, 95 insertions, 12 deletions
diff --git a/src/core/or/protover.c b/src/core/or/protover.c index a882d1a77d..0183704c2c 100644 --- a/src/core/or/protover.c +++ b/src/core/or/protover.c @@ -376,6 +376,10 @@ protocol_list_supports_protocol_or_later(const char *list, return contains; } +/* + * XXX START OF HAZARDOUS ZONE XXX + */ + /** Return the canonical string containing the list of protocols * that we support. **/ @@ -383,25 +387,37 @@ protocol_list_supports_protocol_or_later(const char *list, const char * protover_get_supported_protocols(void) { + /* - * WARNING! + * XXX: WARNING! * * Be EXTREMELY CAREFUL when *removing* versions from this list. If you * remove an entry while it still appears as "recommended" in the consensus, - * you'll cause all the instances without it to warn. If you remove an entry - * while it still appears as "required" in the consensus, you'll cause - * all the instances without it to refuse to connect to the network, and - * shut down. + * you'll cause all the instances without it to warn. + * + * If you remove an entry while it still appears as "required" in the + * consensus, you'll cause all the instances without it to refuse to connect + * to the network, and shut down. + * + * If you need to remove a version from this list, you need to make sure that + * it is not listed in the _current consensuses_: just removing it from the + * required list below is NOT ENOUGH. You need to remove it from the + * required list, and THEN let the authorities update and vote on new + * consensuses without it. Only once those consensuses are out is it safe to + * remove from this list. * - * If you need to remove a version from this list, you need to make sure - * that it is not listed in the _current consensuses_: just removing it from - * the required list in dirvote.c is NOT ENOUGH. You need to remove it from - * the required list dirvote.c, and THEN let the authorities update and vote - * on new consensuses without it. Only once those consensuses are out is - * it safe to remove from this list. + * One concrete example of a very dangerous race that could occur: * - * WARNING! + * If the client required protocol "HSDir=1-2" is then changed in the code + * and released to "HSDir=2" while the consensus stills lists "HSDir=1-2", + * then these clients, even very recent ones, will shutdown because they + * don't support "HSDir=1". + * + * And so, changes need to be done in lockstep as described above. + * + * XXX: WARNING! */ + return "Cons=1-2 " "Desc=1-2 " @@ -419,6 +435,73 @@ protover_get_supported_protocols(void) "Relay=1-2"; } +/* + * XXX: WARNING! + * + * The recommended and required values are hardwired, to avoid disaster. Voting + * on the wrong subprotocols here has the potential to take down the network. + * + * In particular, you need to be EXTREMELY CAREFUL before adding new versions + * to the required protocol list. Doing so will cause every relay or client + * that doesn't support those versions to refuse to connect to the network and + * shut down. + * + * Note that this applies to versions, not just protocols! If you say that + * Foobar=8-9 is required, and the client only has Foobar=9, it will shut down. + * + * It is okay to do this only for SUPER OLD relays that are not supported on + * the network anyway. For clients, we really shouldn't kick them off the + * network unless their presence is causing serious active harm. + * + * The following required and recommended lists MUST be changed BEFORE the + * supported list above is changed in order for those lists to appear in the + * consensus BEFORE. + * + * Please, see the warning in protocol_get_supported_versions(). + * + * XXX: WARNING! + */ + +/** Return the recommended client protocols list that directory authorities + * put in the consensus. */ +const char * +protover_get_recommended_client_protocols(void) +{ + return "Cons=1-2 Desc=1-2 DirCache=1 HSDir=1 HSIntro=3 HSRend=1 " + "Link=4 Microdesc=1-2 Relay=2"; +} + +/** Return the recommended relay protocols list that directory authorities + * put in the consensus. */ +const char * +protover_get_recommended_relay_protocols(void) +{ + return "Cons=1-2 Desc=1-2 DirCache=1 HSDir=1 HSIntro=3 HSRend=1 " + "Link=4 Microdesc=1-2 Relay=2"; +} + +/** Return the required client protocols list that directory authorities + * put in the consensus. */ +const char * +protover_get_required_client_protocols(void) +{ + return "Cons=1-2 Desc=1-2 DirCache=1 HSDir=1 HSIntro=3 HSRend=1 " + "Link=4 Microdesc=1-2 Relay=2"; +} + +/** Return the required relay protocols list that directory authorities + * put in the consensus. */ +const char * +protover_get_required_relay_protocols(void) +{ + return "Cons=1 Desc=1 DirCache=1 HSDir=1 HSIntro=3 HSRend=1 " + "Link=3-4 Microdesc=1 Relay=1-2"; +} + +/* + * XXX END OF HAZARDOUS ZONE XXX + */ + /** The protocols from protover_get_supported_protocols(), as parsed into a * list of proto_entry_t values. Access this via * get_supported_protocol_list. */ |