1 #include <ccan/crypto/siphash24/siphash24.h>
2 #include <ccan/htable/htable.h>
3 #include <common/gossip_rcvd_filter.h>
4 #include <common/memleak.h>
5 #include <common/pseudorand.h>
6 #include <wire/peer_wire.h>
7
msg_key(const u8 * msg)8 static u64 msg_key(const u8 *msg)
9 {
10 return siphash24(siphash_seed(), msg, tal_bytelen(msg));
11 }
12
rehash(const void * key,void * unused)13 static size_t rehash(const void *key, void *unused)
14 {
15 return *(u64 *)key;
16 }
17
destroy_msg_map(struct htable * ht)18 static void destroy_msg_map(struct htable *ht)
19 {
20 htable_clear(ht);
21 }
22
new_msg_map(const tal_t * ctx)23 static struct htable *new_msg_map(const tal_t *ctx)
24 {
25 struct htable *ht = tal(ctx, struct htable);
26
27 htable_init(ht, rehash, NULL);
28 tal_add_destructor(ht, destroy_msg_map);
29 return ht;
30 }
31
32 /* We age by keeping two maps, a current and an old one */
33 struct gossip_rcvd_filter {
34 struct htable *cur, *old;
35 };
36
37 #if DEVELOPER
memleak_help_gossip_rcvd_filter(struct htable * memtable,struct gossip_rcvd_filter * grf)38 static void memleak_help_gossip_rcvd_filter(struct htable *memtable,
39 struct gossip_rcvd_filter *grf)
40 {
41 memleak_remove_htable(memtable, grf->cur);
42 memleak_remove_htable(memtable, grf->old);
43 }
44 #endif
45
new_gossip_rcvd_filter(const tal_t * ctx)46 struct gossip_rcvd_filter *new_gossip_rcvd_filter(const tal_t *ctx)
47 {
48 struct gossip_rcvd_filter *f = tal(ctx, struct gossip_rcvd_filter);
49
50 f->cur = new_msg_map(f);
51 f->old = new_msg_map(f);
52 memleak_add_helper(f, memleak_help_gossip_rcvd_filter);
53 return f;
54 }
55
extract_msg_key(const u8 * msg,u64 * key)56 static bool extract_msg_key(const u8 *msg, u64 *key)
57 {
58 int type = fromwire_peektype(msg);
59
60 if (type != WIRE_CHANNEL_ANNOUNCEMENT
61 && type != WIRE_NODE_ANNOUNCEMENT
62 && type != WIRE_CHANNEL_UPDATE)
63 return false;
64
65 *key = msg_key(msg);
66 return true;
67 }
68
69 /* Add a gossip msg to the received map */
gossip_rcvd_filter_add(struct gossip_rcvd_filter * f,const u8 * msg)70 void gossip_rcvd_filter_add(struct gossip_rcvd_filter *f, const u8 *msg)
71 {
72 u64 key;
73
74 /* We don't attach destructor here directly to tag; would be neat,
75 * but it's also an extra allocation. */
76 if (extract_msg_key(msg, &key)) {
77 htable_add(f->cur, key, tal_dup(f->cur, u64, &key));
78 /* Don't let it fill up forever though. */
79 if (htable_count(f->cur) > 10000)
80 gossip_rcvd_filter_age(f);
81 }
82 }
83
84 /* htable is fast, but it's also horribly manual. */
msg_map_remove(struct htable * ht,u64 key)85 static bool msg_map_remove(struct htable *ht, u64 key)
86 {
87 struct htable_iter i;
88 u64 *c;
89
90 for (c = htable_firstval(ht, &i, key);
91 c;
92 c = htable_nextval(ht, &i, key)) {
93 if (*c == key) {
94 htable_del(ht, key, c);
95 tal_free(c);
96 return true;
97 }
98 }
99 return false;
100 }
101
102 /* Is a gossip msg in the received map? (Removes it) */
gossip_rcvd_filter_del(struct gossip_rcvd_filter * f,const u8 * msg)103 bool gossip_rcvd_filter_del(struct gossip_rcvd_filter *f, const u8 *msg)
104 {
105 u64 key;
106
107 if (!extract_msg_key(msg, &key))
108 return false;
109
110 /* Look in both for gossip. */
111 return msg_map_remove(f->cur, key) || msg_map_remove(f->old, key);
112 }
113
114 /* Flush out old entries. */
gossip_rcvd_filter_age(struct gossip_rcvd_filter * f)115 void gossip_rcvd_filter_age(struct gossip_rcvd_filter *f)
116 {
117 tal_free(f->old);
118 f->old = f->cur;
119 f->cur = new_msg_map(f);
120 }
121