mirror of
https://github.com/lightninglabs/loop
synced 2024-11-13 13:10:30 +00:00
535e964ec9
A database field was already in place to allow channel selection for loop in. Unfortunately this field, which contains a short channel id, isn't easily usable for controlling the loop server payment. Because of non-strict forwarding, it is only possible to constrain a route to a specific last hop pubkey. This commit converts the existing field into a pubkey field.
87 lines
2.4 KiB
Go
87 lines
2.4 KiB
Go
package loopdb
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import (
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"bytes"
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"errors"
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"fmt"
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"github.com/btcsuite/btcd/chaincfg"
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"github.com/coreos/bbolt"
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)
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// migrateLastHop migrates the database to v03, replacing the never used loop in
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// channel by a last hop pubkey.
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func migrateLastHop(tx *bbolt.Tx, chainParams *chaincfg.Params) error {
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rootBucket := tx.Bucket(loopInBucketKey)
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if rootBucket == nil {
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return errors.New("bucket does not exist")
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}
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return rootBucket.ForEach(func(swapHash, v []byte) error {
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// Only go into things that we know are sub-bucket
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// keys.
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if v != nil {
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return nil
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}
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// From the root bucket, we'll grab the next swap
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// bucket for this swap from its swaphash.
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swapBucket := rootBucket.Bucket(swapHash)
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if swapBucket == nil {
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return fmt.Errorf("swap bucket %x not found",
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swapHash)
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}
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// With the main swap bucket obtained, we'll grab the
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// raw swap contract bytes.
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contractBytes := swapBucket.Get(contractKey)
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if contractBytes == nil {
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return errors.New("contract not found")
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}
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const (
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// deprecatedLoopInChannelStart is the starting offset
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// of the old loop in channel field: 8 (initiation time)
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// + 32 (preimage) + 8 (amount requested) + 33 + 33
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// (sender and receiver keys) + 4 (cltv expiry) + 8 + 8
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// (max miner and swap fee) + 4 (initiation height) + 4
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// (conf target) = 142.
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deprecatedLoopInChannelStart = 142
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// expectedTotalLength is the expect total length of the
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// serialized contract. It adds 8 (old loop in channel)
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// + 1 (external htlc) = 9 bytes to
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// deprecatedLoopInChannelStart.
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expectedTotalLength = deprecatedLoopInChannelStart + 9
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)
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// Sanity check to see if the constants above match the contract
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// bytes.
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if len(contractBytes) != expectedTotalLength {
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return errors.New("invalid serialized contract length")
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}
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// Copy the unchanged fields into the buffer.
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b := &bytes.Buffer{}
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_, err := b.Write(contractBytes[:deprecatedLoopInChannelStart])
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if err != nil {
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return err
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}
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// We now set the new last hop field to all zeroes to indicate
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// that there is no restriction.
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var noLastHop [33]byte
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if _, err := b.Write(noLastHop[:]); err != nil {
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return err
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}
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// Append the remaining field ExternalHtlc.
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_, err = b.Write(contractBytes[deprecatedLoopInChannelStart+8:])
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if err != nil {
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return err
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}
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return swapBucket.Put(contractKey, b.Bytes())
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})
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}
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