diff options
Diffstat (limited to 'src/core')
| -rw-r--r-- | src/core/or/protover.c | 105 | ||||
| -rw-r--r-- | src/core/or/protover.h | 4 |
2 files changed, 108 insertions, 1 deletions
diff --git a/src/core/or/protover.c b/src/core/or/protover.c index 87348e0e7d..04df8aeeb8 100644 --- a/src/core/or/protover.c +++ b/src/core/or/protover.c @@ -384,8 +384,13 @@ 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. */ + * that we support. + **/ /// C_RUST_COUPLED: src/rust/protover/protover.rs `SUPPORTED_PROTOCOLS` const char * protover_get_supported_protocols(void) @@ -395,6 +400,38 @@ protover_get_supported_protocols(void) * Remember to edit the SUPPORTED_PROTOCOLS list in protover.rs if you * are editing this list. */ + + /* + * 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. + * + * 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 upgrade 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: + * + * Suppose that the client supports protocols "HsDir=1-2" and the consensus + * requires protocols "HsDir=1-2. If the client supported protocol list is + * then changed to "HSDir=2", while the consensus stills lists "HSDir=1-2", + * then these clients, even very recent ones, will shut down because they + * don't support "HSDir=1". + * + * And so, changes need to be done in strict sequence as described above. + * + * XXX: WARNING! + */ + return "Cons=1-2 " "Desc=1-2 " @@ -414,6 +451,72 @@ protover_get_supported_protocols(void) "Relay=1-3"; } +/* + * 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, so that these lists appear in the + * consensus BEFORE clients need them. + * + * 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=2 Desc=2 DirCache=2 HSDir=2 HSIntro=4 HSRend=2 " + "Link=4-5 Microdesc=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=2 Desc=2 DirCache=2 HSDir=2 HSIntro=4 HSRend=2 " + "Link=4-5 LinkAuth=3 Microdesc=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=2 Desc=2 Link=4 Microdesc=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=2 Desc=2 DirCache=2 HSDir=2 HSIntro=4 HSRend=2 " + "Link=4-5 LinkAuth=3 Microdesc=2 Relay=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. */ diff --git a/src/core/or/protover.h b/src/core/or/protover.h index 622250493d..c0739a092e 100644 --- a/src/core/or/protover.h +++ b/src/core/or/protover.h @@ -73,6 +73,10 @@ bool protover_list_is_invalid(const char *s); int protover_all_supported(const char *s, char **missing); int protover_is_supported_here(protocol_type_t pr, uint32_t ver); const char *protover_get_supported_protocols(void); +const char *protover_get_recommended_client_protocols(void); +const char *protover_get_recommended_relay_protocols(void); +const char *protover_get_required_client_protocols(void); +const char *protover_get_required_relay_protocols(void); char *protover_compute_vote(const struct smartlist_t *list_of_proto_strings, int threshold); |