This appears to have been an oversight in the flat features spec,
and is somewhat implicitly relied on for several new feature bits -
if var_onion_optin is set on a node_announcement (its not allowed
on a channel_announcement), then trying to route through that node
using the pre-tlv formt is somewhat nonsensical, and should be
forbidden.
The feature fields refer to the properties of the channel/node, not the
message itself, so we can still propagate them (and should, to avoid
splitting the network).
If we want to make an incompatible announcement message, we'll use a
different type, or insert an even TLV type.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We simply specify, in each case, where they will appear ("Context").
Because `globalfeatures` is already in use, we fold that into the
renamed `localfeatures` field to unify them (now called `features`),
but dissuade further use.
Note also: we REQUIRE minimal `features` field in
channel_announcement, since otherwise both sides of channel will not
agree and not be able to create their signatures!
Consider these theoretical future features:
`opt_dlog_chan`: a new channel type which uses a new discrete log HTLC
type, but can't support traditional HTLC:
* `init`: presents as odd (optional) or even (if traditional channels
not supported)
* `node_announcement`: the same as above, so you can seek suitable peers.
* `channel_announcement`: presents as even (compulsory), since users need
to use the new HTLCs.
`opt_wumbochan`: a node which allows channels > 2^24 satoshis:
* `init`: presents as odd (optional), or maybe even (if you only want
giant channels)
* `node_announcement`: the same as above, so you can seek suitable peers.
* `channel_announcement`: not present, since size of channel indicates
capacity.
`opt_wumbohtlc`: a channel which allows HTLCs > 2^32 millisatoshis:
* `init`: presents as odd (optional), or even (compulsory)
* `node_announcement`: the same as above, so you can seek suitable peers.
* `channel_announcement`: odd (optional) since you can use the channel
without understanding what this option means.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Co-Authored-By: Bastien Teinturier <31281497+t-bast@users.noreply.github.com>
* BOLT 7: fix cut & paste typo.
This is `reply_channel_range_tlvs`: `query_channel_range_tlvs` is defined
above. Somehow this fix got lost in the merge process, and breaks
our spec parsing.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* BOLT 7: add missing `encoding_type` field in query_short_channel_ids_tlvs / reply_channel_range_tlvs
The implementations have it, and the requirements refer to it,
but it's not actually in the description!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* BOLT 7: clarify specification.
As agreed in http://www.erisian.com.au/meetbot/lightning-dev/2019/lightning-dev.2019-08-05-20.03.html,
checksums are not encoded as encoding_type + byte, but as a straight
array. Referring to them as `*byte` is thus underspecifying them:
they are literally `*channel_update_checksums`.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Do not reply with a node_announcement if the query includes an optional query flag that does not request it.
The current wording could be interpreted as "always follow with node announcements whenever
you reply with a channel announcements" which defeats the point of using query flags (if you want the node
announcements just set the corresponding bits).
We use the more tool-friendly `...*` description for TLV extensions.
Checksums are now serialized as raw arrays, as using zlib compression here would not help.
Since some can be zero (missing updates), it's probably worth
doing the compression thing optionally.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Formatting changes only.
This make tools/extract-formats.py work (well, it misses some stuff
until the tlv-testcases merge, but then it's OK).
We use `tlvs` (for tlv stream), and we refer to TLV records as "being
included" rather than re-using the TLV name.
We even use subtypes for the pairs of checksums and timestamps.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Nodes that support extended queries will append an additional extended query flag to
their `query_channel_range` queries. If the receiver supports extended queries and
understands this flag, it will append the required additional data to its
`reply_channel_range` message.
There is currently only one type of additional data: one timestamp and one checksum
per `channel_update`.
The checksum is a CRC32 checksum computed over the `channel_update`
with `timestamp` and `signature` omitted.
Along with query_short_channel_ids extension, this can be used to
avoid querying `channel_updates` that are older than the ones you
already have, or that are newer but don't include new information.
Nodes can append additional data to their `query_short_channel_ids`
messages, which consists in one flag per short channel id and
specifies what they would like to receive (`node_announcement`,
`channel_announcement`, or/and one `channel_update` or both).
If a node sends its own `channel_update` to a peer node before receiving a `funding_lock`, the peer node may discard because it has not `short_channel_id` yet.
It's trivial to make types->lengths, but not so much the other way.
The types I used here are the ones I found useful in implementation, and
I think add some clarity, though we can certainly argue about them.
There's no normative changes to the spec in here.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Technically this change may result in channels_announcements only
coming from one end. However, because c-lightning already implements
announcement_signatures in this way, in practice this will improve
reliability of channel_announcements.
[ After much bikeshedding, wording rewritten but same effect -- RR ]
Closes#468Closes: #474
'final' and 'endpoint' node don't make much sense out of
context of a payment (in the former case) or when referring to
a non-channel party node. this fixes this
The Initial Sync section is hard to parse, as is, because it's presented
without context. This adds a small clarifying statement, in particular
highlighting where the mode is triggered from (init message features)
and what in particular is being synced (gossip messages)
This optional padding makes it very difficulty to deserialize
node_announcements into internal structs for storage and then
reconstruct the original node_announcement, plus are unused on the
network today and no known implementations construct
node_announcement messages with them.
The fee calculation in BOLT 7 appears to imply that proprtional
fees must be paid on the incoming amount, not the to_forward amount
This is inconsistent with what is actually implemented in the
field (which uses amount_to_forward) and also would make
pathfinding more complicated as the fee would depend on itself,
making calculation no longer simple.
This helps lite nodes a little, but also gives a way of advertising a
lesser capacity than implied onchain.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
