BOLT7: reply_channel_range parameter

[nayuta-ueno]

BOLT7 reply_channel_range requirements

The receiver of query_channel_range:

• For each reply_channel_range:
  • MUST encode a short_channel_id for every open channel it knows in blocks first_blocknum to first_blocknum plus number_of_blocks minus one.

so,

first_blocknum = short_ids[0].block
number_of_blocks = short_ids[LAST].block - first_blocknum + 1

[nayuta-ueno]

node implementation different 1

I send below query_channel_range message (testnet).

[query_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 4294967295

• c-lightning(commit: c029f2fb0fa53eac8191342ef498ab6d5b8b0b17)

[reply_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 4294967295
complete: 01
encoded_short_ids: 0178da459d777c15c5d7c6e7a65712c8dd4d2081f4423a1d045444...

• eclair(eclair-node-0.2-beta8-52821b8.jar)

[reply_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 1288195
number_of_blocks: 165984
complete: 01
encoded_short_ids: 0013a803000104000013a808000055000113a8430000fa000013a84c...

• lnd(commit: 6a78141a2dfde36963b59babdda21ac5ccee6c6f)

[reply_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 4294967295
complete: 01
encoded_short_ids: 0013a803000104000013a808000055000113a8430000fa000013a84c...

[nayuta-ueno]

node implementation different 2

c-lightning and eclair reply reply_channel_range for my query_channel_range whether my init.localfeatures set gossip_queries bit or not.
lnd reply reply_channel_range only when init.localfeatures set gossip_queries bit.

[nayuta-ueno]

send:

[query_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 1

receive from c-lightning/eclair/lnd:

[reply_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 1
complete: 01
encoded_short_ids: 00

I want to allow below:

[reply_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 0
complete: 01
encoded_short_ids: (len=0)

[rustyrussell]

node implementation different 1

I send below query_channel_range message (testnet).

[query_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 4294967295

* c-lightning(commit: c029f2fb0fa53eac8191342ef498ab6d5b8b0b17)

[reply_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 4294967295
complete: 01
encoded_short_ids: 0178da459d777c15c5d7c6e7a65712c8dd4d2081f4423a1d045444...

We revisited this on master recently. If you asked for block 100 and number_of_blocks 4294967295 we got upset and the peer for trying to make us overflow. We now handle it correctly.

* eclair(eclair-node-0.2-beta8-52821b8.jar)

[reply_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 1288195
number_of_blocks: 165984
complete: 01
encoded_short_ids: 0013a803000104000013a808000055000113a8430000fa000013a84c...

This answer is incorrect. It should cover the entire range. It may do so by simply sending two empty reply_channel_range: 0 to 1288194 and (1288195+165984) to 4294967295.

[rustyrussell]

I want to allow below:

[reply_channel_range]
chain_hash: 43497fd7f826957108f4a30fd9cec3aeba79972084e90ead01ea330900000000
first_blocknum: 0
number_of_blocks: 0
complete: 01
encoded_short_ids: (len=0)

We expect the encoding byte to exist. For us, I think, that's easier to create and interpret. Is there a reason you don't want the extra byte?

[nayuta-ueno]

This answer is incorrect. It should cover the entire range. It may do so by simply sending two empty reply_channel_range: 0 to 1288194 and (1288195+165984) to 4294967295.

Oh, I had misunderstanding: complete=1 means "this is last reply_channel_range message".
It is OK.

[nayuta-ueno]

Is there a reason you don't want the extra byte?

Simply len==0 means "no channel_ids".
But either one is fine.
I'll change it to contain "encoding types".

[t-bast]

Superceded by #737