Probing backround service follow-up. by randomlogin · Pull Request #1004 · lightningdevkit/ldk-node

randomlogin · 2026-07-24T11:07:15Z

Closes: #975

Move probing code in builder before the memory leak checker.
Prevent potential overflow due to public channel info fee values.
Account for aggregated fee potentially being bigger than constructed probing path's max htlc bound (doing second pass once we constructed path with fees).

ldk-reviews-bot · 2026-07-24T11:07:18Z

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

tnull

One comment otherwise LGTM

tnull · 2026-07-24T12:05:06Z

+ .checked_mul(channel_update_info.fees.proportional_millionths as u64)
+ .map(|v| v / 1_000_000)?;
+ let fee = (channel_update_info.fees.base_msat as u64).checked_add(proportional_fee)?;
+ forwarded = forwarded.checked_add(fee)?;


Codex:
[P2] Check the HTLC bound before adding the current hop’s fee — /home/tnull/worktrees/ldk-node/pr-1004-latest-20260724/src/probing.rs:698
forwarded initially represents the amount sent through next_channel, including only downstream fees. The code adds the current node’s fee and then compares against that channel’s bounds. That fee is collected on the preceding channel and must not count toward
next_channel.htlc_maximum_msat.
For example, if B→C has a 1,000,000-msat maximum and B charges 1,000 msat, delivering exactly 1,000,000 msat over B→C is valid. This code checks 1,001,000 and rejects the path.
BOLT 7 defines the maximum as what the origin node will send through that channel, while its fee is calculated from amount_to_forward. BOLT 7 channel updates and HTLC fees (https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#htlc-fees)
The bound check should occur before calculating and adding fee.

Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin · 2026-07-24T11:07:15Z

Closes: #975

Move probing code in builder before the memory leak checker.
Prevent potential overflow due to public channel info fee values.
Account for aggregated fee potentially being bigger than constructed probing path's max htlc bound (doing second pass once we constructed path with fees).

ldk-reviews-bot · 2026-07-24T11:07:18Z

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

tnull

One comment otherwise LGTM

tnull · 2026-07-24T12:05:06Z

+ .checked_mul(channel_update_info.fees.proportional_millionths as u64)
+ .map(|v| v / 1_000_000)?;
+ let fee = (channel_update_info.fees.base_msat as u64).checked_add(proportional_fee)?;
+ forwarded = forwarded.checked_add(fee)?;


Codex:
[P2] Check the HTLC bound before adding the current hop’s fee — /home/tnull/worktrees/ldk-node/pr-1004-latest-20260724/src/probing.rs:698
forwarded initially represents the amount sent through next_channel, including only downstream fees. The code adds the current node’s fee and then compares against that channel’s bounds. That fee is collected on the preceding channel and must not count toward
next_channel.htlc_maximum_msat.
For example, if B→C has a 1,000,000-msat maximum and B charges 1,000 msat, delivering exactly 1,000,000 msat over B→C is valid. This code checks 1,001,000 and rejects the path.
BOLT 7 defines the maximum as what the origin node will send through that channel, while its fee is calculated from amount_to_forward. BOLT 7 channel updates and HTLC fees (https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#htlc-fees)
The bound check should occur before calculating and adding fee.

Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin · 2026-07-24T11:07:15Z

Closes: #975

Move probing code in builder before the memory leak checker.
Prevent potential overflow due to public channel info fee values.
Account for aggregated fee potentially being bigger than constructed probing path's max htlc bound (doing second pass once we constructed path with fees).

ldk-reviews-bot · 2026-07-24T11:07:18Z

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

tnull

One comment otherwise LGTM

tnull · 2026-07-24T12:05:06Z

+ .checked_mul(channel_update_info.fees.proportional_millionths as u64)
+ .map(|v| v / 1_000_000)?;
+ let fee = (channel_update_info.fees.base_msat as u64).checked_add(proportional_fee)?;
+ forwarded = forwarded.checked_add(fee)?;


Codex:
[P2] Check the HTLC bound before adding the current hop’s fee — /home/tnull/worktrees/ldk-node/pr-1004-latest-20260724/src/probing.rs:698
forwarded initially represents the amount sent through next_channel, including only downstream fees. The code adds the current node’s fee and then compares against that channel’s bounds. That fee is collected on the preceding channel and must not count toward
next_channel.htlc_maximum_msat.
For example, if B→C has a 1,000,000-msat maximum and B charges 1,000 msat, delivering exactly 1,000,000 msat over B→C is valid. This code checks 1,001,000 and rejects the path.
BOLT 7 defines the maximum as what the origin node will send through that channel, while its fee is calculated from amount_to_forward. BOLT 7 channel updates and HTLC fees (https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#htlc-fees)
The bound check should occur before calculating and adding fee.

Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin · 2026-07-24T11:07:15Z

Closes: #975

Move probing code in builder before the memory leak checker.
Prevent potential overflow due to public channel info fee values.
Account for aggregated fee potentially being bigger than constructed probing path's max htlc bound (doing second pass once we constructed path with fees).

ldk-reviews-bot · 2026-07-24T11:07:18Z

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

tnull

One comment otherwise LGTM

tnull · 2026-07-24T12:05:06Z

+ .checked_mul(channel_update_info.fees.proportional_millionths as u64)
+ .map(|v| v / 1_000_000)?;
+ let fee = (channel_update_info.fees.base_msat as u64).checked_add(proportional_fee)?;
+ forwarded = forwarded.checked_add(fee)?;


Codex:
[P2] Check the HTLC bound before adding the current hop’s fee — /home/tnull/worktrees/ldk-node/pr-1004-latest-20260724/src/probing.rs:698
forwarded initially represents the amount sent through next_channel, including only downstream fees. The code adds the current node’s fee and then compares against that channel’s bounds. That fee is collected on the preceding channel and must not count toward
next_channel.htlc_maximum_msat.
For example, if B→C has a 1,000,000-msat maximum and B charges 1,000 msat, delivering exactly 1,000,000 msat over B→C is valid. This code checks 1,001,000 and rejects the path.
BOLT 7 defines the maximum as what the origin node will send through that channel, while its fee is calculated from amount_to_forward. BOLT 7 channel updates and HTLC fees (https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#htlc-fees)
The bound check should occur before calculating and adding fee.

Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin · 2026-07-24T11:07:15Z

Closes: #975

Move probing code in builder before the memory leak checker.
Prevent potential overflow due to public channel info fee values.
Account for aggregated fee potentially being bigger than constructed probing path's max htlc bound (doing second pass once we constructed path with fees).

ldk-reviews-bot · 2026-07-24T11:07:18Z

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

tnull

One comment otherwise LGTM

tnull · 2026-07-24T12:05:06Z

+ .checked_mul(channel_update_info.fees.proportional_millionths as u64)
+ .map(|v| v / 1_000_000)?;
+ let fee = (channel_update_info.fees.base_msat as u64).checked_add(proportional_fee)?;
+ forwarded = forwarded.checked_add(fee)?;


Codex:
[P2] Check the HTLC bound before adding the current hop’s fee — /home/tnull/worktrees/ldk-node/pr-1004-latest-20260724/src/probing.rs:698
forwarded initially represents the amount sent through next_channel, including only downstream fees. The code adds the current node’s fee and then compares against that channel’s bounds. That fee is collected on the preceding channel and must not count toward
next_channel.htlc_maximum_msat.
For example, if B→C has a 1,000,000-msat maximum and B charges 1,000 msat, delivering exactly 1,000,000 msat over B→C is valid. This code checks 1,001,000 and rejects the path.
BOLT 7 defines the maximum as what the origin node will send through that channel, while its fee is calculated from amount_to_forward. BOLT 7 channel updates and HTLC fees (https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#htlc-fees)
The bound check should occur before calculating and adding fee.

Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin · 2026-07-24T11:07:15Z

Closes: #975

Move probing code in builder before the memory leak checker.
Prevent potential overflow due to public channel info fee values.
Account for aggregated fee potentially being bigger than constructed probing path's max htlc bound (doing second pass once we constructed path with fees).

ldk-reviews-bot · 2026-07-24T11:07:18Z

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

tnull

One comment otherwise LGTM

tnull · 2026-07-24T12:05:06Z

+ .checked_mul(channel_update_info.fees.proportional_millionths as u64)
+ .map(|v| v / 1_000_000)?;
+ let fee = (channel_update_info.fees.base_msat as u64).checked_add(proportional_fee)?;
+ forwarded = forwarded.checked_add(fee)?;


Codex:
[P2] Check the HTLC bound before adding the current hop’s fee — /home/tnull/worktrees/ldk-node/pr-1004-latest-20260724/src/probing.rs:698
forwarded initially represents the amount sent through next_channel, including only downstream fees. The code adds the current node’s fee and then compares against that channel’s bounds. That fee is collected on the preceding channel and must not count toward
next_channel.htlc_maximum_msat.
For example, if B→C has a 1,000,000-msat maximum and B charges 1,000 msat, delivering exactly 1,000,000 msat over B→C is valid. This code checks 1,001,000 and rejects the path.
BOLT 7 defines the maximum as what the origin node will send through that channel, while its fee is calculated from amount_to_forward. BOLT 7 channel updates and HTLC fees (https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#htlc-fees)
The bound check should occur before calculating and adding fee.

Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin · 2026-07-24T11:07:15Z

Closes: #975

Move probing code in builder before the memory leak checker.
Prevent potential overflow due to public channel info fee values.
Account for aggregated fee potentially being bigger than constructed probing path's max htlc bound (doing second pass once we constructed path with fees).

ldk-reviews-bot · 2026-07-24T11:07:18Z

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

tnull

One comment otherwise LGTM

tnull · 2026-07-24T12:05:06Z

+ .checked_mul(channel_update_info.fees.proportional_millionths as u64)
+ .map(|v| v / 1_000_000)?;
+ let fee = (channel_update_info.fees.base_msat as u64).checked_add(proportional_fee)?;
+ forwarded = forwarded.checked_add(fee)?;


Codex:
[P2] Check the HTLC bound before adding the current hop’s fee — /home/tnull/worktrees/ldk-node/pr-1004-latest-20260724/src/probing.rs:698
forwarded initially represents the amount sent through next_channel, including only downstream fees. The code adds the current node’s fee and then compares against that channel’s bounds. That fee is collected on the preceding channel and must not count toward
next_channel.htlc_maximum_msat.
For example, if B→C has a 1,000,000-msat maximum and B charges 1,000 msat, delivering exactly 1,000,000 msat over B→C is valid. This code checks 1,001,000 and rejects the path.
BOLT 7 defines the maximum as what the origin node will send through that channel, while its fee is calculated from amount_to_forward. BOLT 7 channel updates and HTLC fees (https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#htlc-fees)
The bound check should occur before calculating and adding fee.

Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin · 2026-07-24T11:07:15Z

Closes: #975

Move probing code in builder before the memory leak checker.
Prevent potential overflow due to public channel info fee values.
Account for aggregated fee potentially being bigger than constructed probing path's max htlc bound (doing second pass once we constructed path with fees).

ldk-reviews-bot · 2026-07-24T11:07:18Z

👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

tnull

One comment otherwise LGTM

tnull · 2026-07-24T12:05:06Z

+ .checked_mul(channel_update_info.fees.proportional_millionths as u64)
+ .map(|v| v / 1_000_000)?;
+ let fee = (channel_update_info.fees.base_msat as u64).checked_add(proportional_fee)?;
+ forwarded = forwarded.checked_add(fee)?;


Codex:
[P2] Check the HTLC bound before adding the current hop’s fee — /home/tnull/worktrees/ldk-node/pr-1004-latest-20260724/src/probing.rs:698
forwarded initially represents the amount sent through next_channel, including only downstream fees. The code adds the current node’s fee and then compares against that channel’s bounds. That fee is collected on the preceding channel and must not count toward
next_channel.htlc_maximum_msat.
For example, if B→C has a 1,000,000-msat maximum and B charges 1,000 msat, delivering exactly 1,000,000 msat over B→C is valid. This code checks 1,001,000 and rejects the path.
BOLT 7 defines the maximum as what the origin node will send through that channel, while its fee is calculated from amount_to_forward. BOLT 7 channel updates and HTLC fees (https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#htlc-fees)
The bound check should occur before calculating and adding fee.

Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

ldk-reviews-bot requested a review from tnull July 24, 2026 11:17

tnull reviewed Jul 24, 2026
View reviewed changes

Polish background probing service
5dec4e7
Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin force-pushed the probing-service-follow-up branch from 415befb to 5dec4e7Compare July 24, 2026 13:16

randomlogin requested a review from tnull July 24, 2026 13:17

tnull approved these changes Jul 27, 2026
View reviewed changes

tnull merged commit abbed3e into lightningdevkit:mainJul 27, 2026
24 of 26 checks passed

randomlogin deleted the probing-service-follow-up branch July 27, 2026 11:49

ldk-reviews-bot requested a review from tnull July 24, 2026 11:17

tnull reviewed Jul 24, 2026
View reviewed changes

Polish background probing service
5dec4e7
Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin force-pushed the probing-service-follow-up branch from 415befb to 5dec4e7Compare July 24, 2026 13:16

randomlogin requested a review from tnull July 24, 2026 13:17

tnull approved these changes Jul 27, 2026
View reviewed changes

tnull merged commit abbed3e into lightningdevkit:mainJul 27, 2026
24 of 26 checks passed

randomlogin deleted the probing-service-follow-up branch July 27, 2026 11:49

ldk-reviews-bot requested a review from tnull July 24, 2026 11:17

tnull reviewed Jul 24, 2026
View reviewed changes

Polish background probing service
5dec4e7
Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin force-pushed the probing-service-follow-up branch from 415befb to 5dec4e7Compare July 24, 2026 13:16

randomlogin requested a review from tnull July 24, 2026 13:17

tnull approved these changes Jul 27, 2026
View reviewed changes

tnull merged commit abbed3e into lightningdevkit:mainJul 27, 2026
24 of 26 checks passed

randomlogin deleted the probing-service-follow-up branch July 27, 2026 11:49

ldk-reviews-bot requested a review from tnull July 24, 2026 11:17

tnull reviewed Jul 24, 2026
View reviewed changes

Polish background probing service
5dec4e7
Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin force-pushed the probing-service-follow-up branch from 415befb to 5dec4e7Compare July 24, 2026 13:16

randomlogin requested a review from tnull July 24, 2026 13:17

tnull approved these changes Jul 27, 2026
View reviewed changes

tnull merged commit abbed3e into lightningdevkit:mainJul 27, 2026
24 of 26 checks passed

randomlogin deleted the probing-service-follow-up branch July 27, 2026 11:49

ldk-reviews-bot requested a review from tnull July 24, 2026 11:17

tnull reviewed Jul 24, 2026
View reviewed changes

Polish background probing service
5dec4e7
Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin force-pushed the probing-service-follow-up branch from 415befb to 5dec4e7Compare July 24, 2026 13:16

randomlogin requested a review from tnull July 24, 2026 13:17

tnull approved these changes Jul 27, 2026
View reviewed changes

tnull merged commit abbed3e into lightningdevkit:mainJul 27, 2026
24 of 26 checks passed

randomlogin deleted the probing-service-follow-up branch July 27, 2026 11:49

ldk-reviews-bot requested a review from tnull July 24, 2026 11:17

tnull reviewed Jul 24, 2026
View reviewed changes

Polish background probing service
5dec4e7
Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin force-pushed the probing-service-follow-up branch from 415befb to 5dec4e7Compare July 24, 2026 13:16

randomlogin requested a review from tnull July 24, 2026 13:17

tnull approved these changes Jul 27, 2026
View reviewed changes

tnull merged commit abbed3e into lightningdevkit:mainJul 27, 2026
24 of 26 checks passed

randomlogin deleted the probing-service-follow-up branch July 27, 2026 11:49

ldk-reviews-bot requested a review from tnull July 24, 2026 11:17

tnull reviewed Jul 24, 2026
View reviewed changes

Polish background probing service
5dec4e7
Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin force-pushed the probing-service-follow-up branch from 415befb to 5dec4e7Compare July 24, 2026 13:16

randomlogin requested a review from tnull July 24, 2026 13:17

tnull approved these changes Jul 27, 2026
View reviewed changes

tnull merged commit abbed3e into lightningdevkit:mainJul 27, 2026
24 of 26 checks passed

randomlogin deleted the probing-service-follow-up branch July 27, 2026 11:49

ldk-reviews-bot requested a review from tnull July 24, 2026 11:17

tnull reviewed Jul 24, 2026
View reviewed changes

Polish background probing service
5dec4e7
Move probing code in builder before the memory leak checker. Prevent potential overflow due to public channel info fee values. Account aggregated fee potentially being bigger than constructed porbing path's max htlc bound.

randomlogin force-pushed the probing-service-follow-up branch from 415befb to 5dec4e7Compare July 24, 2026 13:16

randomlogin requested a review from tnull July 24, 2026 13:17

tnull approved these changes Jul 27, 2026
View reviewed changes

tnull merged commit abbed3e into lightningdevkit:mainJul 27, 2026
24 of 26 checks passed

randomlogin deleted the probing-service-follow-up branch July 27, 2026 11:49

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