git.bitcoin.ninja Git - rapid-gossip-sync-server/blob - src/serialization.rs

   1 use std::cmp::max;
   2 use std::collections::HashMap;
   3 use std::time::{SystemTime, UNIX_EPOCH};
   4
   5 use bitcoin::BlockHash;
   6 use bitcoin::hashes::Hash;
   7 use lightning::ln::msgs::{UnsignedChannelAnnouncement, UnsignedChannelUpdate};
   8 use lightning::util::ser::{BigSize, Writeable};
   9 use crate::config;
  10
  11 use crate::lookup::{DeltaSet, DirectedUpdateDelta};
  12
  13 pub(super) struct SerializationSet {
  14         pub(super) announcements: Vec<UnsignedChannelAnnouncement>,
  15         pub(super) updates: Vec<UpdateSerialization>,
  16         pub(super) full_update_defaults: DefaultUpdateValues,
  17         pub(super) latest_seen: u32,
  18         pub(super) chain_hash: BlockHash,
  19 }
  20
  21 pub(super) struct DefaultUpdateValues {
  22         pub(super) cltv_expiry_delta: u16,
  23         pub(super) htlc_minimum_msat: u64,
  24         pub(super) fee_base_msat: u32,
  25         pub(super) fee_proportional_millionths: u32,
  26         pub(super) htlc_maximum_msat: u64,
  27 }
  28
  29 impl Default for DefaultUpdateValues {
  30         fn default() -> Self {
  31                 Self {
  32                         cltv_expiry_delta: 0,
  33                         htlc_minimum_msat: 0,
  34                         fee_base_msat: 0,
  35                         fee_proportional_millionths: 0,
  36                         htlc_maximum_msat: 0,
  37                 }
  38         }
  39 }
  40
  41 pub(super) struct MutatedProperties {
  42         pub(super) flags: bool,
  43         pub(super) cltv_expiry_delta: bool,
  44         pub(super) htlc_minimum_msat: bool,
  45         pub(super) fee_base_msat: bool,
  46         pub(super) fee_proportional_millionths: bool,
  47         pub(super) htlc_maximum_msat: bool,
  48 }
  49
  50 impl Default for MutatedProperties {
  51         fn default() -> Self {
  52                 Self {
  53                         flags: false,
  54                         cltv_expiry_delta: false,
  55                         htlc_minimum_msat: false,
  56                         fee_base_msat: false,
  57                         fee_proportional_millionths: false,
  58                         htlc_maximum_msat: false,
  59                 }
  60         }
  61 }
  62
  63 impl MutatedProperties {
  64         /// Does not include flags because the flag byte is always sent in full
  65         fn len(&self) -> u8 {
  66                 let mut mutations = 0;
  67                 if self.cltv_expiry_delta { mutations += 1; };
  68                 if self.htlc_minimum_msat { mutations += 1; };
  69                 if self.fee_base_msat { mutations += 1; };
  70                 if self.fee_proportional_millionths { mutations += 1; };
  71                 if self.htlc_maximum_msat { mutations += 1; };
  72                 mutations
  73         }
  74 }
  75
  76 pub(super) enum UpdateSerialization {
  77         Full(UnsignedChannelUpdate),
  78         Incremental(UnsignedChannelUpdate, MutatedProperties),
  79         Reminder(u64, u8),
  80 }
  81 impl UpdateSerialization {
  82         pub(super) fn scid(&self) -> u64 {
  83                 match self {
  84                         UpdateSerialization::Full(latest_update)|
  85                         UpdateSerialization::Incremental(latest_update, _) => latest_update.short_channel_id,
  86                         UpdateSerialization::Reminder(scid, _) => *scid,
  87                 }
  88         }
  89
  90         fn flags(&self) -> u8 {
  91                 match self {
  92                         UpdateSerialization::Full(latest_update)|
  93                         UpdateSerialization::Incremental(latest_update, _) => latest_update.flags,
  94                         UpdateSerialization::Reminder(_, flags) => *flags,
  95                 }
  96         }
  97 }
  98
  99 struct FullUpdateValueHistograms {
 100         cltv_expiry_delta: HashMap<u16, usize>,
 101         htlc_minimum_msat: HashMap<u64, usize>,
 102         fee_base_msat: HashMap<u32, usize>,
 103         fee_proportional_millionths: HashMap<u32, usize>,
 104         htlc_maximum_msat: HashMap<u64, usize>,
 105 }
 106
 107 pub(super) fn serialize_delta_set(delta_set: DeltaSet, last_sync_timestamp: u32) -> SerializationSet {
 108         let mut serialization_set = SerializationSet {
 109                 announcements: vec![],
 110                 updates: vec![],
 111                 full_update_defaults: Default::default(),
 112                 chain_hash: BlockHash::all_zeros(),
 113                 latest_seen: 0,
 114         };
 115
 116         let mut chain_hash_set = false;
 117
 118         let mut full_update_histograms = FullUpdateValueHistograms {
 119                 cltv_expiry_delta: Default::default(),
 120                 htlc_minimum_msat: Default::default(),
 121                 fee_base_msat: Default::default(),
 122                 fee_proportional_millionths: Default::default(),
 123                 htlc_maximum_msat: Default::default(),
 124         };
 125
 126         let mut record_full_update_in_histograms = |full_update: &UnsignedChannelUpdate| {
 127                 *full_update_histograms.cltv_expiry_delta.entry(full_update.cltv_expiry_delta).or_insert(0) += 1;
 128                 *full_update_histograms.htlc_minimum_msat.entry(full_update.htlc_minimum_msat).or_insert(0) += 1;
 129                 *full_update_histograms.fee_base_msat.entry(full_update.fee_base_msat).or_insert(0) += 1;
 130                 *full_update_histograms.fee_proportional_millionths.entry(full_update.fee_proportional_millionths).or_insert(0) += 1;
 131                 *full_update_histograms.htlc_maximum_msat.entry(full_update.htlc_maximum_msat).or_insert(0) += 1;
 132         };
 133
 134         // if the previous seen update happened more than 6 days ago, the client may have pruned it, and an incremental update wouldn't work
 135         let non_incremental_previous_update_threshold_timestamp = SystemTime::now().checked_sub(config::CHANNEL_REMINDER_AGE).unwrap().duration_since(UNIX_EPOCH).unwrap().as_secs() as u32;
 136
 137         for (scid, channel_delta) in delta_set.into_iter() {
 138
 139                 // any announcement chain hash is gonna be the same value. Just set it from the first one.
 140                 let channel_announcement_delta = channel_delta.announcement.as_ref().unwrap();
 141                 if !chain_hash_set {
 142                         chain_hash_set = true;
 143                         serialization_set.chain_hash = channel_announcement_delta.announcement.chain_hash.clone();
 144                 }
 145
 146                 let current_announcement_seen = channel_announcement_delta.seen;
 147                 let is_new_announcement = current_announcement_seen >= last_sync_timestamp;
 148                 let is_newly_included_announcement = if let Some(first_update_seen) = channel_delta.first_bidirectional_updates_seen {
 149                         first_update_seen >= last_sync_timestamp
 150                 } else {
 151                         false
 152                 };
 153                 let send_announcement = is_new_announcement || is_newly_included_announcement;
 154                 if send_announcement {
 155                         serialization_set.latest_seen = max(serialization_set.latest_seen, current_announcement_seen);
 156                         serialization_set.announcements.push(channel_delta.announcement.unwrap().announcement);
 157                 }
 158
 159                 let direction_a_updates = channel_delta.updates.0;
 160                 let direction_b_updates = channel_delta.updates.1;
 161
 162                 let mut categorize_directed_update_serialization = |directed_updates: Option<DirectedUpdateDelta>| {
 163                         if let Some(updates) = directed_updates {
 164                                 if let Some(latest_update_delta) = updates.latest_update_after_seen {
 165                                         let latest_update = latest_update_delta.update;
 166                                         assert_eq!(latest_update.short_channel_id, scid, "Update in DB had wrong SCID column");
 167
 168                                         // the returned seen timestamp should be the latest of all the returned
 169                                         // announcements and latest updates
 170                                         serialization_set.latest_seen = max(serialization_set.latest_seen, latest_update_delta.seen);
 171
 172                                         if let Some(update_delta) = updates.last_update_before_seen {
 173                                                 let mutated_properties = updates.mutated_properties;
 174                                                 if send_announcement || mutated_properties.len() == 5 || update_delta.seen <= non_incremental_previous_update_threshold_timestamp {
 175                                                         // all five values have changed, it makes more sense to just
 176                                                         // serialize the update as a full update instead of as a change
 177                                                         // this way, the default values can be computed more efficiently
 178                                                         record_full_update_in_histograms(&latest_update);
 179                                                         serialization_set.updates.push(UpdateSerialization::Full(latest_update));
 180                                                 } else if mutated_properties.len() > 0 || mutated_properties.flags {
 181                                                         // we don't count flags as mutated properties
 182                                                         serialization_set.updates.push(
 183                                                                 UpdateSerialization::Incremental(latest_update, mutated_properties));
 184                                                 }
 185                                         } else {
 186                                                 // serialize the full update
 187                                                 record_full_update_in_histograms(&latest_update);
 188                                                 serialization_set.updates.push(UpdateSerialization::Full(latest_update));
 189                                         }
 190                                 } else if is_newly_included_announcement {
 191                                         if let Some(unannounced_update) = updates.last_update_before_seen {
 192                                                 serialization_set.updates.push(UpdateSerialization::Full(unannounced_update.update));
 193                                         }
 194                                 } else if let Some(flags) = updates.serialization_update_flags {
 195                                         serialization_set.updates.push(UpdateSerialization::Reminder(scid, flags));
 196                                 }
 197                         }
 198                 };
 199
 200                 categorize_directed_update_serialization(direction_a_updates);
 201                 categorize_directed_update_serialization(direction_b_updates);
 202         }
 203
 204         let default_update_values = DefaultUpdateValues {
 205                 cltv_expiry_delta: find_most_common_histogram_entry_with_default(full_update_histograms.cltv_expiry_delta, 0),
 206                 htlc_minimum_msat: find_most_common_histogram_entry_with_default(full_update_histograms.htlc_minimum_msat, 0),
 207                 fee_base_msat: find_most_common_histogram_entry_with_default(full_update_histograms.fee_base_msat, 0),
 208                 fee_proportional_millionths: find_most_common_histogram_entry_with_default(full_update_histograms.fee_proportional_millionths, 0),
 209                 htlc_maximum_msat: find_most_common_histogram_entry_with_default(full_update_histograms.htlc_maximum_msat, 0),
 210         };
 211
 212         serialization_set.full_update_defaults = default_update_values;
 213         serialization_set
 214 }
 215
 216 pub fn serialize_stripped_channel_announcement(announcement: &UnsignedChannelAnnouncement, node_id_a_index: usize, node_id_b_index: usize, previous_scid: u64) -> Vec<u8> {
 217         let mut stripped_announcement = vec![];
 218
 219         announcement.features.write(&mut stripped_announcement).unwrap();
 220
 221         if previous_scid > announcement.short_channel_id {
 222                 panic!("unsorted scids!");
 223         }
 224         let scid_delta = BigSize(announcement.short_channel_id - previous_scid);
 225         scid_delta.write(&mut stripped_announcement).unwrap();
 226
 227         // write indices of node ids rather than the node IDs themselves
 228         BigSize(node_id_a_index as u64).write(&mut stripped_announcement).unwrap();
 229         BigSize(node_id_b_index as u64).write(&mut stripped_announcement).unwrap();
 230
 231         // println!("serialized CA: {}, \n{:?}\n{:?}\n", announcement.short_channel_id, announcement.node_id_1, announcement.node_id_2);
 232         stripped_announcement
 233 }
 234
 235 pub(super) fn serialize_stripped_channel_update(update: &UpdateSerialization, default_values: &DefaultUpdateValues, previous_scid: u64) -> Vec<u8> {
 236         let mut serialized_flags = update.flags();
 237
 238         if previous_scid > update.scid() {
 239                 panic!("unsorted scids!");
 240         }
 241
 242         let mut delta_serialization = Vec::new();
 243         let mut prefixed_serialization = Vec::new();
 244
 245         match update {
 246                 UpdateSerialization::Full(latest_update) => {
 247                         if latest_update.cltv_expiry_delta != default_values.cltv_expiry_delta {
 248                                 serialized_flags |= 0b_0100_0000;
 249                                 latest_update.cltv_expiry_delta.write(&mut delta_serialization).unwrap();
 250                         }
 251
 252                         if latest_update.htlc_minimum_msat != default_values.htlc_minimum_msat {
 253                                 serialized_flags |= 0b_0010_0000;
 254                                 latest_update.htlc_minimum_msat.write(&mut delta_serialization).unwrap();
 255                         }
 256
 257                         if latest_update.fee_base_msat != default_values.fee_base_msat {
 258                                 serialized_flags |= 0b_0001_0000;
 259                                 latest_update.fee_base_msat.write(&mut delta_serialization).unwrap();
 260                         }
 261
 262                         if latest_update.fee_proportional_millionths != default_values.fee_proportional_millionths {
 263                                 serialized_flags |= 0b_0000_1000;
 264                                 latest_update.fee_proportional_millionths.write(&mut delta_serialization).unwrap();
 265                         }
 266
 267                         if latest_update.htlc_maximum_msat != default_values.htlc_maximum_msat {
 268                                 serialized_flags |= 0b_0000_0100;
 269                                 latest_update.htlc_maximum_msat.write(&mut delta_serialization).unwrap();
 270                         }
 271                 }
 272                 UpdateSerialization::Incremental(latest_update, mutated_properties) => {
 273                         // indicate that this update is incremental
 274                         serialized_flags |= 0b_1000_0000;
 275
 276                         if mutated_properties.cltv_expiry_delta {
 277                                 serialized_flags |= 0b_0100_0000;
 278                                 latest_update.cltv_expiry_delta.write(&mut delta_serialization).unwrap();
 279                         }
 280
 281                         if mutated_properties.htlc_minimum_msat {
 282                                 serialized_flags |= 0b_0010_0000;
 283                                 latest_update.htlc_minimum_msat.write(&mut delta_serialization).unwrap();
 284                         }
 285
 286                         if mutated_properties.fee_base_msat {
 287                                 serialized_flags |= 0b_0001_0000;
 288                                 latest_update.fee_base_msat.write(&mut delta_serialization).unwrap();
 289                         }
 290
 291                         if mutated_properties.fee_proportional_millionths {
 292                                 serialized_flags |= 0b_0000_1000;
 293                                 latest_update.fee_proportional_millionths.write(&mut delta_serialization).unwrap();
 294                         }
 295
 296                         if mutated_properties.htlc_maximum_msat {
 297                                 serialized_flags |= 0b_0000_0100;
 298                                 latest_update.htlc_maximum_msat.write(&mut delta_serialization).unwrap();
 299                         }
 300                 },
 301                 UpdateSerialization::Reminder(_, _) => {
 302                         // indicate that this update is incremental
 303                         serialized_flags |= 0b_1000_0000;
 304                 }
 305         }
 306         let scid_delta = BigSize(update.scid() - previous_scid);
 307         scid_delta.write(&mut prefixed_serialization).unwrap();
 308
 309         serialized_flags.write(&mut prefixed_serialization).unwrap();
 310         prefixed_serialization.append(&mut delta_serialization);
 311
 312         prefixed_serialization
 313 }
 314
 315 pub(super) fn find_most_common_histogram_entry_with_default<T: Copy>(histogram: HashMap<T, usize>, default: T) -> T {
 316         let most_frequent_entry = histogram.iter().max_by(|a, b| a.1.cmp(&b.1));
 317         if let Some(entry_details) = most_frequent_entry {
 318                 // .0 is the value
 319                 // .1 is the frequency
 320                 return entry_details.0.to_owned();
 321         }
 322         // the default should pretty much always be a 0 as T
 323         // though for htlc maximum msat it could be a u64::max
 324         default
 325 }