commit df78fb24511e890a1a2bf00127db604919bbdc0e Author: George Kadianakis desnacked@riseup.net Date: Tue Oct 23 16:34:43 2018 +0300

Documentation: Document which descriptor elements are (im)mutable. --- src/feature/hs/hs_service.h | 58 +++++++++++++++++++++++++++++---------------- 1 file changed, 37 insertions(+), 21 deletions(-)

diff --git a/src/feature/hs/hs_service.h b/src/feature/hs/hs_service.h index 863d96bb4..9804a4571 100644 --- a/src/feature/hs/hs_service.h +++ b/src/feature/hs/hs_service.h @@ -99,48 +99,64 @@ typedef struct hs_service_intropoints_t { digestmap_t *failed_id; } hs_service_intropoints_t;

-/* Representation of a service descriptor. */ +/* Representation of a service descriptor. + * + * Some elements of the descriptor are mutable whereas others are immutable: + + * Immutable elements are initialized once when the descriptor is built (when + * service descriptors gets rotated). This means that these elements are + * initialized once and then they don't change for the lifetime of the + * descriptor. See build_service_descriptor(). + * + * Mutable elements are initialized when we build the descriptor but they are + * also altered during the lifetime of the descriptor. They could be + * _refreshed_ everytime we upload the descriptor (which happens multiple times + * over the lifetime of the descriptor), or through periodic events. We do this + * for elements like the descriptor revision counter and various + * certificates. See refresh_service_descriptor() and + * update_service_descriptor_intro_points(). + */ typedef struct hs_service_descriptor_t { - /* Decoded descriptor. This object is used for encoding when the service - * publishes the descriptor. */ + /* Mutable: Decoded descriptor. This object is used for encoding when the + * service publishes the descriptor. */ hs_descriptor_t *desc;

- /* Client authorization ephemeral keypair. */ + /* Immutable: Client authorization ephemeral keypair. */ curve25519_keypair_t auth_ephemeral_kp;

- /* Descriptor cookie used to encrypt the descriptor, when the client - * authorization is enabled */ + /* Immutable: Descriptor cookie used to encrypt the descriptor, when the + * client authorization is enabled */ uint8_t descriptor_cookie[HS_DESC_DESCRIPTOR_COOKIE_LEN];

- /* Descriptor signing keypair. */ + /* Immutable: Descriptor signing keypair. */ ed25519_keypair_t signing_kp;

- /* Blinded keypair derived from the master identity public key. */ + /* Immutable: Blinded keypair derived from the master identity public key. */ ed25519_keypair_t blinded_kp;

- /* When is the next time when we should upload the descriptor. */ + /* Mutable: When is the next time when we should upload the descriptor. */ time_t next_upload_time;

- /* Introduction points assign to this descriptor which contains - * hs_service_intropoints_t object indexed by authentication key (the RSA - * key if the node is legacy). */ + /* Mutable: Introduction points assign to this descriptor which contains + * hs_service_intropoints_t object indexed by authentication key (the RSA key + * if the node is legacy). */ hs_service_intropoints_t intro_points;

- /* The time period number this descriptor has been created for. */ + /* Immutable: The time period number this descriptor has been created for. */ uint64_t time_period_num;

- /* True iff we have missing intro points for this descriptor because we - * couldn't pick any nodes. */ + /* Mutable: True iff we have missing intro points for this descriptor because + * we couldn't pick any nodes. */ unsigned int missing_intro_points : 1;

- /** List of the responsible HSDirs (their b64ed identity digest) last time we - * uploaded this descriptor. If the set of responsible HSDirs is different - * from this list, this means we received new dirinfo and we need to - * reupload our descriptor. */ + /** Mutable: List of the responsible HSDirs (their b64ed identity digest) + * last time we uploaded this descriptor. If the set of responsible HSDirs + * is different from this list, this means we received new dirinfo and we + * need to reupload our descriptor. */ smartlist_t *previous_hsdirs;

- /** The OPE cipher for encrypting revision counters for this descriptor. - * Tied to the descriptor blinded key. */ + /** Immutable: The OPE cipher for encrypting revision counters for this + * descriptor. Tied to the descriptor blinded key. */ struct crypto_ope_t *ope_cipher; } hs_service_descriptor_t;