12313002221

Committed 13 Dec 2024 09:25AM UTC coverage: 57.486% (+8.6%) from 48.92%

Build # 12313002221

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push

github

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web-flow

Commit Message

Merge pull request #9343 from ellemouton/contextGuard

fn: expand the ContextGuard and add tests

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77.78

/discovery/ban.go

package discovery

import (
        "errors"
        "sync"
        "time"

        "github.com/btcsuite/btcd/btcec/v2"
        "github.com/lightninglabs/neutrino/cache"
        "github.com/lightninglabs/neutrino/cache/lru"
        "github.com/lightningnetwork/lnd/channeldb"
        "github.com/lightningnetwork/lnd/lnwire"
)

const (
        // maxBannedPeers limits the maximum number of banned pubkeys that
        // we'll store.
        // TODO(eugene): tune.
        maxBannedPeers = 10_000

        // banThreshold is the point at which non-channel peers will be banned.
        // TODO(eugene): tune.
        banThreshold = 100

        // banTime is the amount of time that the non-channel peer will be
        // banned for. Channel announcements from channel peers will be dropped
        // if it's not one of our channels.
        // TODO(eugene): tune.
        banTime = time.Hour * 48

        // resetDelta is the time after a peer's last ban update that we'll
        // reset its ban score.
        // TODO(eugene): tune.
        resetDelta = time.Hour * 48

        // purgeInterval is how often we'll remove entries from the
        // peerBanIndex and allow peers to be un-banned. This interval is also
        // used to reset ban scores of peers that aren't banned.
        purgeInterval = time.Minute * 10
)

var ErrPeerBanned = errors.New("peer has bypassed ban threshold - banning")

// ClosedChannelTracker handles closed channels being gossiped to us.
type ClosedChannelTracker interface {
        // GraphCloser is used to mark channels as closed and to check whether
        // certain channels are closed.
        GraphCloser

        // IsChannelPeer checks whether we have a channel with a peer.
        IsChannelPeer(*btcec.PublicKey) (bool, error)
}

// GraphCloser handles tracking closed channels by their scid.
type GraphCloser interface {
        // PutClosedScid marks a channel as closed so that we won't validate
        // channel announcements for it again.
        PutClosedScid(lnwire.ShortChannelID) error

        // IsClosedScid checks if a short channel id is closed.
        IsClosedScid(lnwire.ShortChannelID) (bool, error)
}

// NodeInfoInquirier handles queries relating to specific nodes and channels
// they may have with us.
type NodeInfoInquirer interface {
        // FetchOpenChannels returns the set of channels that we have with the
        // peer identified by the passed-in public key.
        FetchOpenChannels(*btcec.PublicKey) ([]*channeldb.OpenChannel, error)
}

// ScidCloserMan helps the gossiper handle closed channels that are in the
// ChannelGraph.
type ScidCloserMan struct {
        graph     GraphCloser
        channelDB NodeInfoInquirer
}

// NewScidCloserMan creates a new ScidCloserMan.
func NewScidCloserMan(graph GraphCloser,
        channelDB NodeInfoInquirer) *ScidCloserMan {

        return &ScidCloserMan{
                graph:     graph,
                channelDB: channelDB,
        }
}

// PutClosedScid marks scid as closed so the gossiper can ignore this channel
// in the future.
func (s *ScidCloserMan) PutClosedScid(scid lnwire.ShortChannelID) error {
        return s.graph.PutClosedScid(scid)
}

// IsClosedScid checks whether scid is closed so that the gossiper can ignore
// it.
func (s *ScidCloserMan) IsClosedScid(scid lnwire.ShortChannelID) (bool,
        error) {

        return s.graph.IsClosedScid(scid)
}

// IsChannelPeer checks whether we have a channel with the peer.
func (s *ScidCloserMan) IsChannelPeer(peerKey *btcec.PublicKey) (bool, error) {
        chans, err := s.channelDB.FetchOpenChannels(peerKey)
        if err != nil {
                return false, err
        }

        return len(chans) > 0, nil
}

// A compile-time constraint to ensure ScidCloserMan implements
// ClosedChannelTracker.
var _ ClosedChannelTracker = (*ScidCloserMan)(nil)

// cachedBanInfo is used to track a peer's ban score and if it is banned.
type cachedBanInfo struct {
        score      uint64
        lastUpdate time.Time
}

// Size returns the "size" of an entry.
func (c *cachedBanInfo) Size() (uint64, error) {
        return 1, nil
}

// isBanned returns true if the ban score is greater than the ban threshold.
func (c *cachedBanInfo) isBanned() bool {
        return c.score >= banThreshold
}

// banman is responsible for banning peers that are misbehaving. The banman is
// in-memory and will be reset upon restart of LND. If a node's pubkey is in
// the peerBanIndex, it has a ban score. Ban scores start at 1 and are
// incremented by 1 for each instance of misbehavior. It uses an LRU cache to
// cut down on memory usage in case there are many banned peers and to protect
// against DoS.
type banman struct {
        // peerBanIndex tracks our peers' ban scores and if they are banned and
        // for how long. The ban score is incremented when our peer gives us
        // gossip messages that are invalid.
        peerBanIndex *lru.Cache[[33]byte, *cachedBanInfo]

        wg   sync.WaitGroup
        quit chan struct{}
}

// newBanman creates a new banman with the default maxBannedPeers.
func newBanman() *banman {
        return &banman{
                peerBanIndex: lru.NewCache[[33]byte, *cachedBanInfo](
                        maxBannedPeers,
                ),
                quit: make(chan struct{}),
        }
}

// start kicks off the banman by calling purgeExpiredBans.
func (b *banman) start() {
        b.wg.Add(1)
        go b.purgeExpiredBans()
}

// stop halts the banman.
func (b *banman) stop() {
        close(b.quit)
        b.wg.Wait()
}

// purgeOldEntries removes ban entries if their ban has expired.
func (b *banman) purgeExpiredBans() {
        defer b.wg.Done()

        purgeTicker := time.NewTicker(purgeInterval)
        defer purgeTicker.Stop()

        for {
                select {
                case <-purgeTicker.C:
                        b.purgeBanEntries()

                case <-b.quit:
                        return
                }
        }
}

// purgeBanEntries does two things:
// - removes peers from our ban list whose ban timer is up
// - removes peers whose ban scores have expired.
func (b *banman) purgeBanEntries() {
        keysToRemove := make([][33]byte, 0)

        sweepEntries := func(pubkey [33]byte, banInfo *cachedBanInfo) bool {
                if banInfo.isBanned() {
                        // If the peer is banned, check if the ban timer has
                        // expired.
                        if banInfo.lastUpdate.Add(banTime).Before(time.Now()) {
                                keysToRemove = append(keysToRemove, pubkey)
                        }

                        return true
                }

                if banInfo.lastUpdate.Add(resetDelta).Before(time.Now()) {
                        // Remove non-banned peers whose ban scores have
                        // expired.
                        keysToRemove = append(keysToRemove, pubkey)
                }

                return true
        }

        b.peerBanIndex.Range(sweepEntries)

        for _, key := range keysToRemove {
                b.peerBanIndex.Delete(key)
        }
}

// isBanned checks whether the peer identified by the pubkey is banned.
func (b *banman) isBanned(pubkey [33]byte) bool {
        banInfo, err := b.peerBanIndex.Get(pubkey)
        switch {
        case errors.Is(err, cache.ErrElementNotFound):
                return false

        default:
                return banInfo.isBanned()
        }
}

// incrementBanScore increments a peer's ban score.
func (b *banman) incrementBanScore(pubkey [33]byte) {
        banInfo, err := b.peerBanIndex.Get(pubkey)
        switch {
        case errors.Is(err, cache.ErrElementNotFound):
                cachedInfo := &cachedBanInfo{
                        score:      1,
                        lastUpdate: time.Now(),
                }
                _, _ = b.peerBanIndex.Put(pubkey, cachedInfo)
        default:
                cachedInfo := &cachedBanInfo{
                        score:      banInfo.score + 1,
                        lastUpdate: time.Now(),
                }

                _, _ = b.peerBanIndex.Put(pubkey, cachedInfo)
        }
}

1	package discovery
2
3	import (
4	"errors"
5	"sync"
6	"time"
7
8	"github.com/btcsuite/btcd/btcec/v2"
9	"github.com/lightninglabs/neutrino/cache"
10	"github.com/lightninglabs/neutrino/cache/lru"
11	"github.com/lightningnetwork/lnd/channeldb"
12	"github.com/lightningnetwork/lnd/lnwire"
13	)
14
15	const (
16	// maxBannedPeers limits the maximum number of banned pubkeys that
17	// we'll store.
18	// TODO(eugene): tune.
19	maxBannedPeers = 10_000
20
21	// banThreshold is the point at which non-channel peers will be banned.
22	// TODO(eugene): tune.
23	banThreshold = 100
24
25	// banTime is the amount of time that the non-channel peer will be
26	// banned for. Channel announcements from channel peers will be dropped
27	// if it's not one of our channels.
28	// TODO(eugene): tune.
29	banTime = time.Hour * 48
30
31	// resetDelta is the time after a peer's last ban update that we'll
32	// reset its ban score.
33	// TODO(eugene): tune.
34	resetDelta = time.Hour * 48
35
36	// purgeInterval is how often we'll remove entries from the
37	// peerBanIndex and allow peers to be un-banned. This interval is also
38	// used to reset ban scores of peers that aren't banned.
39	purgeInterval = time.Minute * 10
40	)
41
42	var ErrPeerBanned = errors.New("peer has bypassed ban threshold - banning")
43
44	// ClosedChannelTracker handles closed channels being gossiped to us.
45	type ClosedChannelTracker interface {
46	// GraphCloser is used to mark channels as closed and to check whether
47	// certain channels are closed.
48	GraphCloser
49
50	// IsChannelPeer checks whether we have a channel with a peer.
51	IsChannelPeer(*btcec.PublicKey) (bool, error)
52	}
53
54	// GraphCloser handles tracking closed channels by their scid.
55	type GraphCloser interface {
56	// PutClosedScid marks a channel as closed so that we won't validate
57	// channel announcements for it again.
58	PutClosedScid(lnwire.ShortChannelID) error
59
60	// IsClosedScid checks if a short channel id is closed.
61	IsClosedScid(lnwire.ShortChannelID) (bool, error)
62	}
63
64	// NodeInfoInquirier handles queries relating to specific nodes and channels
65	// they may have with us.
66	type NodeInfoInquirer interface {
67	// FetchOpenChannels returns the set of channels that we have with the
68	// peer identified by the passed-in public key.
69	FetchOpenChannels(btcec.PublicKey) ([]channeldb.OpenChannel, error)
70	}
71
72	// ScidCloserMan helps the gossiper handle closed channels that are in the
73	// ChannelGraph.
74	type ScidCloserMan struct {
75	graph GraphCloser
76	channelDB NodeInfoInquirer
77	}
78
79	// NewScidCloserMan creates a new ScidCloserMan.
80	func NewScidCloserMan(graph GraphCloser,
81	channelDB NodeInfoInquirer) *ScidCloserMan {	×
82		×
83	return &ScidCloserMan{	×
84	graph: graph,	×
85	channelDB: channelDB,	×
86	}	×
87	}	×
88
89	// PutClosedScid marks scid as closed so the gossiper can ignore this channel
90	// in the future.
91	func (s *ScidCloserMan) PutClosedScid(scid lnwire.ShortChannelID) error {	×
92	return s.graph.PutClosedScid(scid)	×
93	}	×
94
95	// IsClosedScid checks whether scid is closed so that the gossiper can ignore
96	// it.
97	func (s *ScidCloserMan) IsClosedScid(scid lnwire.ShortChannelID) (bool,
98	error) {	×
99		×
100	return s.graph.IsClosedScid(scid)	×
101	}	×
102
103	// IsChannelPeer checks whether we have a channel with the peer.
104	func (s ScidCloserMan) IsChannelPeer(peerKey btcec.PublicKey) (bool, error) {	×
105	chans, err := s.channelDB.FetchOpenChannels(peerKey)	×
106	if err != nil {	×
107	return false, err	×
108	}	×
109
110	return len(chans) > 0, nil	×
111	}
112
113	// A compile-time constraint to ensure ScidCloserMan implements
114	// ClosedChannelTracker.
115	var _ ClosedChannelTracker = (*ScidCloserMan)(nil)
116
117	// cachedBanInfo is used to track a peer's ban score and if it is banned.
118	type cachedBanInfo struct {
119	score uint64
120	lastUpdate time.Time
121	}
122
123	// Size returns the "size" of an entry.
124	func (c *cachedBanInfo) Size() (uint64, error) {	603✔
125	return 1, nil	603✔
126	}	603✔
127
128	// isBanned returns true if the ban score is greater than the ban threshold.
129	func (c *cachedBanInfo) isBanned() bool {	211✔
130	return c.score >= banThreshold	211✔
131	}	211✔
132
133	// banman is responsible for banning peers that are misbehaving. The banman is
134	// in-memory and will be reset upon restart of LND. If a node's pubkey is in
135	// the peerBanIndex, it has a ban score. Ban scores start at 1 and are
136	// incremented by 1 for each instance of misbehavior. It uses an LRU cache to
137	// cut down on memory usage in case there are many banned peers and to protect
138	// against DoS.
139	type banman struct {
140	// peerBanIndex tracks our peers' ban scores and if they are banned and
141	// for how long. The ban score is incremented when our peer gives us
142	// gossip messages that are invalid.
143	peerBanIndex lru.Cache[[33]byte, cachedBanInfo]
144
145	wg sync.WaitGroup
146	quit chan struct{}
147	}
148
149	// newBanman creates a new banman with the default maxBannedPeers.
150	func newBanman() *banman {	28✔
151	return &banman{	28✔
152	peerBanIndex: lru.NewCache[[33]byte, *cachedBanInfo](	28✔
153	maxBannedPeers,	28✔
154	),	28✔
155	quit: make(chan struct{}),	28✔
156	}	28✔
157	}	28✔
158
159	// start kicks off the banman by calling purgeExpiredBans.
160	func (b *banman) start() {	27✔
161	b.wg.Add(1)	27✔
162	go b.purgeExpiredBans()	27✔
163	}	27✔
164
165	// stop halts the banman.
166	func (b *banman) stop() {	27✔
167	close(b.quit)	27✔
168	b.wg.Wait()	27✔
169	}	27✔
170
171	// purgeOldEntries removes ban entries if their ban has expired.
172	func (b *banman) purgeExpiredBans() {	27✔
173	defer b.wg.Done()	27✔
174		27✔
175	purgeTicker := time.NewTicker(purgeInterval)	27✔
176	defer purgeTicker.Stop()	27✔
177		27✔
178	for {	54✔
179	select {	27✔
180	case <-purgeTicker.C:	×
181	b.purgeBanEntries()	×
182
183	case <-b.quit:	27✔
184	return	27✔
185	}
186	}
187	}
188
189	// purgeBanEntries does two things:
190	// - removes peers from our ban list whose ban timer is up
191	// - removes peers whose ban scores have expired.
192	func (b *banman) purgeBanEntries() {	4✔
193	keysToRemove := make([][33]byte, 0)	4✔
194		4✔
195	sweepEntries := func(pubkey [33]byte, banInfo *cachedBanInfo) bool {	8✔
196	if banInfo.isBanned() {	6✔
197	// If the peer is banned, check if the ban timer has	2✔
198	// expired.	2✔
199	if banInfo.lastUpdate.Add(banTime).Before(time.Now()) {	3✔
200	keysToRemove = append(keysToRemove, pubkey)	1✔
201	}	1✔
202
203	return true	2✔
204	}
205
206	if banInfo.lastUpdate.Add(resetDelta).Before(time.Now()) {	3✔
207	// Remove non-banned peers whose ban scores have	1✔
208	// expired.	1✔
209	keysToRemove = append(keysToRemove, pubkey)	1✔
210	}	1✔
211
212	return true	2✔
213	}
214
215	b.peerBanIndex.Range(sweepEntries)	4✔
216		4✔
217	for _, key := range keysToRemove {	6✔
218	b.peerBanIndex.Delete(key)	2✔
219	}	2✔
220	}
221
222	// isBanned checks whether the peer identified by the pubkey is banned.
223	func (b *banman) isBanned(pubkey [33]byte) bool {	208✔
224	banInfo, err := b.peerBanIndex.Get(pubkey)	208✔
225	switch {	208✔
226	case errors.Is(err, cache.ErrElementNotFound):	1✔
227	return false	1✔
228
229	default:	207✔
230	return banInfo.isBanned()	207✔
231	}
232	}
233
234	// incrementBanScore increments a peer's ban score.
235	func (b *banman) incrementBanScore(pubkey [33]byte) {	303✔
236	banInfo, err := b.peerBanIndex.Get(pubkey)	303✔
237	switch {	303✔
238	case errors.Is(err, cache.ErrElementNotFound):	5✔
239	cachedInfo := &cachedBanInfo{	5✔
240	score: 1,	5✔
241	lastUpdate: time.Now(),	5✔
242	}	5✔
243	_, _ = b.peerBanIndex.Put(pubkey, cachedInfo)	5✔
244	default:	298✔
245	cachedInfo := &cachedBanInfo{	298✔
246	score: banInfo.score + 1,	298✔
247	lastUpdate: time.Now(),	298✔
248	}	298✔
249		298✔
250	_, _ = b.peerBanIndex.Put(pubkey, cachedInfo)	298✔
251	}
252	}

lightningnetwork / lnd / 12313002221

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