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Rusty Russell f6312d9a70 BOLT 7: query_messages option.

[ This was a joint effort by many people, with iterations not
  indicated in this final commit: thanks to all who reviewed and
  polished!  Particularly: @jimpo @cdecker @sstone @ZmnSCPxj ]

This enables three new functions:

1. query_short_channel_ids: they will send channel_announcement /
   channel_update / node_announcement followed by reply_short_channel_ids_done.
2. query_channel_range: they will send one or more reply_channel_range
   with the short_channel_ids in these blocks.
3. gossip_timestamp_filter: filters what gossip they send.

It also changes behavior: we no longer send a `channel_announcement`
until we have at least one `channel_update`.  The announcement is
fairly useless without an update already, but this in particular
enables reasonable timestamp filtering (channel_announcement does not
have an explicit timestamp).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

2018-06-28 00:21:23 +00:00

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BOLT #9: Assigned Feature Flags

This document tracks the assignment of localfeatures and globalfeatures flags in the init message (BOLT #1) along with the features flag fields in the channel_announcement and node_announcement messages (BOLT #7). The flags are tracked separately, since new flags will likely be added over time.

The features flags in the routing messages are a subset of the globalfeatures flags, as localfeatures, by definition, are only of interest to direct peers.

Flags are numbered from the least-significant bit, at bit 0 (i.e. 0x1, an even bit). They are generally assigned in pairs so that features can be introduced as optional (odd bits) and later upgraded to be compulsory (even bits), which will be refused by outdated nodes: see BOLT #1: The init Message.

Assigned `localfeatures` flags

These flags may only be used in the init message:

Bits	Name	Description	Link
0/1	`option_data_loss_protect`	Requires or supports extra `channel_reestablish` fields	BOLT #2
3	`initial_routing_sync`	Indicates that the sending node needs a complete routing information dump	BOLT #7
4/5	`option_upfront_shutdown_script`	Commits to a shutdown scriptpubkey when opening channel	BOLT #2
6/7	`gossip_queries`	More sophisticated gossip control	BOLT #7

Assigned `globalfeatures` flags

There are currently no globalfeatures flags.

Requirements

The requirements for receiving specific bits are defined in the linked sections in the table above. The requirements for feature bits that are not defined above can be found in BOLT #1: The init Message.

Rationale

There is no even bit for initial_routing_sync, as there would be little point: a local node can't determine if a remote node complies, and it must interpret the flag, as defined in the initial spec.

This work is licensed under a Creative Commons Attribution 4.0 International License.

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