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queries.c
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/* Routines to generate and handle gossip query messages */
#include "config.h"
#include <bitcoin/chainparams.h>
#include <ccan/array_size/array_size.h>
#include <ccan/asort/asort.h>
#include <ccan/crc32c/crc32c.h>
#include <common/daemon_conn.h>
#include <common/decode_array.h>
#include <common/status.h>
#include <common/type_to_string.h>
#include <common/wire_error.h>
#include <gossipd/gossip_generation.h>
#include <gossipd/gossipd.h>
#include <gossipd/gossipd_wiregen.h>
#include <gossipd/queries.h>
#include <gossipd/routing.h>
#include <zlib.h>
#if DEVELOPER
static u32 dev_max_encoding_bytes = -1U;
#endif
/* BOLT #7:
*
* There are several messages which contain a long array of
* `short_channel_id`s (called `encoded_short_ids`) so we include an encoding
* byte which allows for different encoding schemes to be defined in the future
*/
static u8 *encoding_start(const tal_t *ctx, bool prepend_encoding)
{
u8 *ret;
if (prepend_encoding) {
ret = tal_arr(ctx, u8, 1);
ret[0] = ARR_UNCOMPRESSED;
} else
ret = tal_arr(ctx, u8, 0);
return ret;
}
/* Marshal a single short_channel_id */
static void encoding_add_short_channel_id(u8 **encoded,
const struct short_channel_id *scid)
{
towire_short_channel_id(encoded, scid);
}
/* Marshal a single channel_update_timestamps */
static void encoding_add_timestamps(u8 **encoded,
const struct channel_update_timestamps *ts)
{
towire_channel_update_timestamps(encoded, ts);
}
/* Marshal a single query flag (we don't query, so not currently used) */
static void encoding_add_query_flag(u8 **encoded, bigsize_t flag)
{
towire_bigsize(encoded, flag);
}
static bool encoding_end(const u8 *encoded, size_t max_bytes)
{
#if DEVELOPER
if (tal_count(encoded) > dev_max_encoding_bytes)
return false;
#endif
return tal_count(encoded) <= max_bytes;
}
/* Query this peer for these short-channel-ids. */
bool query_short_channel_ids(struct daemon *daemon,
struct peer *peer,
const struct short_channel_id *scids,
const u8 *query_flags,
void (*cb)(struct peer *peer, bool complete))
{
u8 *encoded, *msg;
struct tlv_query_short_channel_ids_tlvs *tlvs;
/* BOLT #7:
*
* 1. type: 261 (`query_short_channel_ids`) (`gossip_queries`)
* 2. data:
* * [`chain_hash`:`chain_hash`]
* * [`u16`:`len`]
* * [`len*byte`:`encoded_short_ids`]
*/
const size_t reply_overhead = 32 + 2;
size_t max_encoded_bytes = 65535 - 2 - reply_overhead;
/* Can't query if they don't have gossip_queries_feature */
if (!peer->gossip_queries_feature)
return false;
/* BOLT #7:
* - MAY include an optional `query_flags`. If so:
* - MUST set `encoding_type`, as for `encoded_short_ids`.
* - Each query flag is a minimally-encoded bigsize.
* - MUST encode one query flag per `short_channel_id`.
*/
if (query_flags)
assert(tal_count(query_flags) == tal_count(scids));
/* BOLT #7:
*
* The sender:
* - MUST NOT send `query_short_channel_ids` if it has sent a previous
* `query_short_channel_ids` to this peer and not received
* `reply_short_channel_ids_end`.
*/
if (peer->scid_query_outstanding)
return false;
encoded = encoding_start(tmpctx, true);
for (size_t i = 0; i < tal_count(scids); i++) {
/* BOLT #7:
*
* Encoding types:
* * `0`: uncompressed array of `short_channel_id` types, in
* ascending order.
*/
assert(i == 0 || scids[i].u64 > scids[i-1].u64);
encoding_add_short_channel_id(&encoded, &scids[i]);
}
if (!encoding_end(encoded, max_encoded_bytes)) {
status_broken("query_short_channel_ids: %zu is too many",
tal_count(scids));
return false;
}
if (query_flags) {
struct tlv_query_short_channel_ids_tlvs_query_flags *tlvq;
tlvs = tlv_query_short_channel_ids_tlvs_new(tmpctx);
tlvq = tlvs->query_flags = tal(tlvs,
struct tlv_query_short_channel_ids_tlvs_query_flags);
tlvq->encoding_type = ARR_UNCOMPRESSED;
tlvq->encoded_query_flags = encoding_start(tlvq, false);
for (size_t i = 0; i < tal_count(query_flags); i++)
encoding_add_query_flag(&tlvq->encoded_query_flags,
query_flags[i]);
max_encoded_bytes -= tal_bytelen(encoded);
if (!encoding_end(tlvq->encoded_query_flags,
max_encoded_bytes)) {
status_broken("query_short_channel_ids:"
" %zu query_flags is too many",
tal_count(query_flags));
return false;
}
} else
tlvs = NULL;
msg = towire_query_short_channel_ids(NULL,
&chainparams->genesis_blockhash,
encoded, tlvs);
queue_peer_msg(peer, take(msg));
peer->scid_query_outstanding = true;
peer->scid_query_cb = cb;
status_peer_debug(&peer->id, "sending query for %zu scids",
tal_count(scids));
return true;
}
/* The peer can ask about an array of short channel ids: we don't assemble the
* reply immediately but process them one at a time in dump_gossip which is
* called when there's nothing more important to send. */
const u8 *handle_query_short_channel_ids(struct peer *peer, const u8 *msg)
{
struct bitcoin_blkid chain;
u8 *encoded;
struct short_channel_id *scids;
bigsize_t *flags;
struct tlv_query_short_channel_ids_tlvs *tlvs;
if (!fromwire_query_short_channel_ids(tmpctx, msg, &chain, &encoded,
&tlvs)) {
return towire_warningfmt(peer, NULL,
"Bad query_short_channel_ids w/tlvs %s",
tal_hex(tmpctx, msg));
}
if (tlvs->query_flags) {
/* BOLT #7:
*
* The receiver:
*...
* - if the incoming message includes
* `query_short_channel_ids_tlvs`:
* - if `encoding_type` is not a known encoding type:
* - MAY send a `warning`.
* - MAY close the connection.
*/
flags = decode_scid_query_flags(tmpctx, tlvs->query_flags);
if (!flags) {
return towire_warningfmt(peer, NULL,
"Bad query_short_channel_ids query_flags %s",
tal_hex(tmpctx, msg));
}
} else
flags = NULL;
/* BOLT #7
*
* The receiver:
* ...
* - if does not maintain up-to-date channel information for `chain_hash`:
* - MUST set `complete` to 0.
*/
if (!bitcoin_blkid_eq(&chainparams->genesis_blockhash, &chain)) {
status_peer_debug(&peer->id,
"sent query_short_channel_ids chainhash %s",
type_to_string(tmpctx, struct bitcoin_blkid, &chain));
return towire_reply_short_channel_ids_end(peer, &chain, 0);
}
/* BOLT #7:
*
* - if it has not sent `reply_short_channel_ids_end` to a
* previously received `query_short_channel_ids` from this
* sender:
* - MAY send a `warning`.
* - MAY close the connection.
*/
if (peer->scid_queries || peer->scid_query_nodes) {
return towire_warningfmt(peer, NULL,
"Bad concurrent query_short_channel_ids");
}
scids = decode_short_ids(tmpctx, encoded);
if (!scids) {
return towire_warningfmt(peer, NULL,
"Bad query_short_channel_ids encoding %s",
tal_hex(tmpctx, encoded));
}
/* BOLT #7:
*
* The receiver:
*...
* - if `encoded_query_flags` does not decode to exactly one flag per
* `short_channel_id`:
* - MAY send a `warning`.
* - MAY close the connection.
*/
if (!flags) {
/* Pretend they asked for everything. */
flags = tal_arr(tmpctx, bigsize_t, tal_count(scids));
memset(flags, 0xFF, tal_bytelen(flags));
} else {
if (tal_count(flags) != tal_count(scids)) {
return towire_warningfmt(peer, NULL,
"Bad query_short_channel_ids flags count %zu scids %zu",
tal_count(flags), tal_count(scids));
}
}
/* BOLT #7:
*
* - MUST respond to each known `short_channel_id`:
*...
* - SHOULD NOT wait for the next outgoing gossip flush to send
* these.
*/
peer->scid_queries = tal_steal(peer, scids);
peer->scid_query_flags = tal_steal(peer, flags);
peer->scid_query_idx = 0;
peer->scid_query_nodes = tal_arr(peer, struct node_id, 0);
/* Notify the daemon_conn-write loop to invoke maybe_send_query_responses_peer */
daemon_conn_wake(peer->daemon->connectd);
return NULL;
}
/*~ We can send multiple replies when the peer queries for all channels in
* a given range of blocks; each one indicates the range of blocks it covers. */
static void send_reply_channel_range(struct peer *peer,
u32 first_blocknum, u32 number_of_blocks,
const struct short_channel_id *scids,
const struct channel_update_timestamps *tstamps,
const struct channel_update_checksums *csums,
size_t num_scids,
bool final)
{
/* BOLT #7:
*
* - MUST respond with one or more `reply_channel_range`:
* - MUST set with `chain_hash` equal to that of `query_channel_range`,
* - MUST limit `number_of_blocks` to the maximum number of blocks
* whose results could fit in `encoded_short_ids`
*/
u8 *encoded_scids = encoding_start(tmpctx, true);
u8 *encoded_timestamps = encoding_start(tmpctx, false);
struct tlv_reply_channel_range_tlvs *tlvs
= tlv_reply_channel_range_tlvs_new(tmpctx);
/* Encode them all */
for (size_t i = 0; i < num_scids; i++)
encoding_add_short_channel_id(&encoded_scids, &scids[i]);
encoding_end(encoded_scids, tal_bytelen(encoded_scids));
if (tstamps) {
for (size_t i = 0; i < num_scids; i++)
encoding_add_timestamps(&encoded_timestamps, &tstamps[i]);
tlvs->timestamps_tlv = tal(tlvs, struct tlv_reply_channel_range_tlvs_timestamps_tlv);
tlvs->timestamps_tlv->encoding_type = ARR_UNCOMPRESSED;
encoding_end(encoded_timestamps,
tal_bytelen(encoded_timestamps));
tlvs->timestamps_tlv->encoded_timestamps
= tal_steal(tlvs, encoded_timestamps);
}
/* Must be a tal object! */
if (csums)
tlvs->checksums_tlv = tal_dup_arr(tlvs,
struct channel_update_checksums,
csums, num_scids, 0);
/* BOLT #7:
*
* - MUST set `sync_complete` to `false` if this is not the final
* `reply_channel_range`.
*/
u8 *msg = towire_reply_channel_range(NULL,
&chainparams->genesis_blockhash,
first_blocknum,
number_of_blocks,
final, encoded_scids, tlvs);
queue_peer_msg(peer, take(msg));
}
/* BOLT #7:
*
* The checksum of a `channel_update` is the CRC32C checksum as specified in
* [RFC3720](https://tools.ietf.org/html/rfc3720#appendix-B.4) of this
* `channel_update` without its `signature` and `timestamp` fields.
*/
static u32 crc32_of_update(const u8 *channel_update)
{
u32 sum;
const u8 *parts[2];
size_t sizes[ARRAY_SIZE(parts)];
get_cupdate_parts(channel_update, parts, sizes);
sum = 0;
for (size_t i = 0; i < ARRAY_SIZE(parts); i++)
sum = crc32c(sum, parts[i], sizes[i]);
return sum;
}
static void get_checksum_and_timestamp(struct routing_state *rstate,
const struct chan *chan,
int direction,
u32 *tstamp, u32 *csum)
{
const struct half_chan *hc = &chan->half[direction];
if (!is_chan_public(chan) || !is_halfchan_defined(hc)) {
*tstamp = *csum = 0;
} else {
const u8 *update = gossip_store_get(tmpctx, rstate->gs,
hc->bcast.index);
*tstamp = hc->bcast.timestamp;
*csum = crc32_of_update(update);
}
}
/* FIXME: This assumes that the tlv type encodes into 1 byte! */
static size_t tlv_overhead(size_t num_entries, size_t size)
{
return 1 + bigsize_len(num_entries * size);
}
/* How many entries can I fit in a reply? */
static size_t max_entries(enum query_option_flags query_option_flags)
{
/* BOLT #7:
*
* 1. type: 264 (`reply_channel_range`) (`gossip_queries`)
* 2. data:
* * [`chain_hash`:`chain_hash`]
* * [`u32`:`first_blocknum`]
* * [`u32`:`number_of_blocks`]
* * [`byte`:`sync_complete`]
* * [`u16`:`len`]
* * [`len*byte`:`encoded_short_ids`]
*/
const size_t reply_overhead = 32 + 4 + 4 + 1 + 2;
size_t max_encoded_bytes = 65535 - 2 - reply_overhead;
size_t per_entry_size, max_num;
per_entry_size = sizeof(struct short_channel_id);
/* Upper bound to start. */
max_num = max_encoded_bytes / per_entry_size;
/* If we add timestamps, we need to encode tlv */
if (query_option_flags & QUERY_ADD_TIMESTAMPS) {
max_encoded_bytes -= tlv_overhead(max_num,
sizeof(struct channel_update_timestamps));
per_entry_size += sizeof(struct channel_update_timestamps);
}
if (query_option_flags & QUERY_ADD_CHECKSUMS) {
max_encoded_bytes -= tlv_overhead(max_num,
sizeof(struct channel_update_checksums));
per_entry_size += sizeof(struct channel_update_checksums);
}
#if DEVELOPER
if (max_encoded_bytes > dev_max_encoding_bytes)
max_encoded_bytes = dev_max_encoding_bytes;
/* Always let one through! */
if (max_encoded_bytes < per_entry_size)
max_encoded_bytes = per_entry_size;
#endif
return max_encoded_bytes / per_entry_size;
}
/* This gets all the scids they asked for, and optionally the timestamps and checksums */
static struct short_channel_id *gather_range(const tal_t *ctx,
struct routing_state *rstate,
u32 first_blocknum, u32 number_of_blocks,
enum query_option_flags query_option_flags,
struct channel_update_timestamps **tstamps,
struct channel_update_checksums **csums)
{
struct short_channel_id scid, *scids;
u32 end_block;
bool scid_ok;
scids = tal_arr(ctx, struct short_channel_id, 0);
if (query_option_flags & QUERY_ADD_TIMESTAMPS)
*tstamps = tal_arr(ctx, struct channel_update_timestamps, 0);
else
*tstamps = NULL;
if (query_option_flags & QUERY_ADD_CHECKSUMS)
*csums = tal_arr(ctx, struct channel_update_checksums, 0);
else
*csums = NULL;
/* Avoid underflow: we don't use block 0 anyway */
if (first_blocknum == 0)
scid_ok = mk_short_channel_id(&scid, 1, 0, 0);
else
scid_ok = mk_short_channel_id(&scid, first_blocknum, 0, 0);
scid.u64--;
/* Out of range? No blocks then. */
if (!scid_ok)
return NULL;
if (number_of_blocks == 0)
return NULL;
/* Fix up number_of_blocks to avoid overflow. */
end_block = first_blocknum + number_of_blocks - 1;
if (end_block < first_blocknum)
end_block = UINT_MAX;
/* We keep a `uintmap` of `short_channel_id` to `struct chan *`.
* Unlike a htable, it's efficient to iterate through, but it only
* works because each short_channel_id is basically a 64-bit unsigned
* integer.
*
* First we iterate and gather all the short channel ids. */
while (uintmap_after(&rstate->chanmap, &scid.u64)) {
struct chan *chan;
struct channel_update_timestamps ts;
struct channel_update_checksums cs;
if (short_channel_id_blocknum(&scid) > end_block)
break;
/* FIXME: Store csum in header. */
chan = get_channel(rstate, &scid);
if (!is_chan_public(chan))
continue;
tal_arr_expand(&scids, scid);
/* Don't calc csums if we don't even care */
if (!(query_option_flags
& (QUERY_ADD_TIMESTAMPS|QUERY_ADD_CHECKSUMS)))
continue;
get_checksum_and_timestamp(rstate, chan, 0,
&ts.timestamp_node_id_1,
&cs.checksum_node_id_1);
get_checksum_and_timestamp(rstate, chan, 1,
&ts.timestamp_node_id_2,
&cs.checksum_node_id_2);
if (query_option_flags & QUERY_ADD_TIMESTAMPS)
tal_arr_expand(tstamps, ts);
if (query_option_flags & QUERY_ADD_CHECKSUMS)
tal_arr_expand(csums, cs);
}
return scids;
}
/*~ When we need to send an array of channels, it might go over our 64k packet
* size. But because we use compression, we can't actually tell how much
* we'll use. We pack them into the maximum amount for uncompressed, then
* compress afterwards.
*/
static void queue_channel_ranges(struct peer *peer,
u32 first_blocknum, u32 number_of_blocks,
enum query_option_flags query_option_flags)
{
struct routing_state *rstate = peer->daemon->rstate;
struct channel_update_timestamps *tstamps;
struct channel_update_checksums *csums;
struct short_channel_id *scids;
size_t off, limit;
scids = gather_range(tmpctx, rstate, first_blocknum, number_of_blocks,
query_option_flags, &tstamps, &csums);
limit = max_entries(query_option_flags);
off = 0;
/* We need to send an empty msg if we have nothing! */
do {
size_t n = tal_count(scids) - off;
u32 this_num_blocks;
if (n > limit) {
status_debug("reply_channel_range: splitting %zu-%zu of %zu",
off, off + limit, tal_count(scids));
n = limit;
/* ... and reduce to a block boundary. */
while (short_channel_id_blocknum(&scids[off + n - 1])
== short_channel_id_blocknum(&scids[off + limit])) {
/* We assume one block doesn't have limit #
* channels. If it does, we have to violate
* spec and send over multiple blocks. */
if (n == 0) {
status_broken("reply_channel_range: "
"could not fit %zu scids for %u!",
limit,
short_channel_id_blocknum(&scids[off + n - 1]));
n = limit;
break;
}
n--;
}
/* Get *next* channel, add num blocks */
this_num_blocks
= short_channel_id_blocknum(&scids[off + n])
- first_blocknum;
} else
/* Last one must end with correct total */
this_num_blocks = number_of_blocks;
send_reply_channel_range(peer, first_blocknum, this_num_blocks,
scids + off,
query_option_flags & QUERY_ADD_TIMESTAMPS
? tstamps + off : NULL,
query_option_flags & QUERY_ADD_CHECKSUMS
? csums + off : NULL,
n,
this_num_blocks == number_of_blocks);
first_blocknum += this_num_blocks;
number_of_blocks -= this_num_blocks;
off += n;
} while (number_of_blocks);
}
/*~ The peer can ask for all channels in a series of blocks. We reply with one
* or more messages containing the short_channel_ids. */
const u8 *handle_query_channel_range(struct peer *peer, const u8 *msg)
{
struct bitcoin_blkid chain_hash;
u32 first_blocknum, number_of_blocks;
enum query_option_flags query_option_flags;
struct tlv_query_channel_range_tlvs *tlvs;
if (!fromwire_query_channel_range(msg, msg, &chain_hash,
&first_blocknum, &number_of_blocks,
&tlvs)) {
return towire_warningfmt(peer, NULL,
"Bad query_channel_range w/tlvs %s",
tal_hex(tmpctx, msg));
}
if (tlvs->query_option)
query_option_flags = *tlvs->query_option;
else
query_option_flags = 0;
/* BOLT #7
*
* The receiver of `query_channel_range`:
* ...
* - if does not maintain up-to-date channel information for `chain_hash`:
* - MUST set `complete` to 0.
*/
if (!bitcoin_blkid_eq(&chainparams->genesis_blockhash, &chain_hash)) {
status_peer_debug(&peer->id,
"query_channel_range with chainhash %s",
type_to_string(tmpctx, struct bitcoin_blkid,
&chain_hash));
u8 *end = towire_reply_channel_range(NULL, &chain_hash, first_blocknum,
number_of_blocks, false, NULL, NULL);
queue_peer_msg(peer, take(end));
return NULL;
}
/* Fix up number_of_blocks to avoid overflow. */
if (first_blocknum + number_of_blocks < first_blocknum)
number_of_blocks = UINT_MAX - first_blocknum;
queue_channel_ranges(peer, first_blocknum, number_of_blocks,
query_option_flags);
return NULL;
}
/* Append these scids (and optional timestamps) to our pending replies */
static u8 *append_range_reply(struct peer *peer,
const struct short_channel_id *scids,
const struct tlv_reply_channel_range_tlvs_timestamps_tlv
*timestamps_tlv)
{
u16 i, old_num, added;
const struct channel_update_timestamps *ts;
/* Zero means "no timestamp" */
const static struct channel_update_timestamps zero_ts = { 0, 0 };
if (timestamps_tlv) {
ts = decode_channel_update_timestamps(tmpctx,
timestamps_tlv);
if (!ts)
return towire_warningfmt(peer, NULL,
"reply_channel_range can't decode timestamps.");
if (tal_count(ts) != tal_count(scids)) {
return towire_warningfmt(peer, NULL,
"reply_channel_range %zu timestamps when %zu scids?",
tal_count(ts),
tal_count(scids));
}
} else
ts = NULL;
old_num = tal_count(peer->range_replies);
added = tal_count(scids);
for (i = 0; i < added; i++) {
tal_resize(&peer->range_replies, old_num + i + 1);
peer->range_replies[old_num + i].scid = scids[i];
if (ts)
peer->range_replies[old_num + i].ts = ts[i];
else
peer->range_replies[old_num + i].ts = zero_ts;
}
return NULL;
}
/*~ This is the reply we get when we send query_channel_range; we keep
* expecting them until the entire range we asked for is covered. */
const u8 *handle_reply_channel_range(struct peer *peer, const u8 *msg)
{
struct bitcoin_blkid chain;
u8 sync_complete;
u32 first_blocknum, number_of_blocks, start, end;
u8 *encoded;
struct short_channel_id *scids;
const struct range_query_reply *replies;
const u8 *err;
void (*cb)(struct peer *peer,
u32 first_blocknum, u32 number_of_blocks,
const struct range_query_reply *replies);
struct tlv_reply_channel_range_tlvs *tlvs;
if (!fromwire_reply_channel_range(tmpctx, msg, &chain, &first_blocknum,
&number_of_blocks, &sync_complete,
&encoded, &tlvs)) {
return towire_warningfmt(peer, NULL,
"Bad reply_channel_range w/tlvs %s",
tal_hex(tmpctx, msg));
}
if (!bitcoin_blkid_eq(&chainparams->genesis_blockhash, &chain)) {
return towire_warningfmt(peer, NULL,
"reply_channel_range for bad chain: %s",
tal_hex(tmpctx, msg));
}
if (!peer->range_replies) {
return towire_warningfmt(peer, NULL,
"reply_channel_range without query: %s",
tal_hex(tmpctx, msg));
}
/* Beware overflow! */
if (first_blocknum + number_of_blocks < first_blocknum) {
return towire_warningfmt(peer, NULL,
"reply_channel_range invalid %u+%u",
first_blocknum, number_of_blocks);
}
scids = decode_short_ids(tmpctx, encoded);
if (!scids) {
return towire_warningfmt(peer, NULL,
"Bad reply_channel_range encoding %s",
tal_hex(tmpctx, encoded));
}
status_peer_debug(&peer->id,
"reply_channel_range %u+%u (of %u+%u) %zu scids",
first_blocknum, number_of_blocks,
peer->range_first_blocknum,
peer->range_end_blocknum - peer->range_first_blocknum,
tal_count(scids));
/* BOLT #7:
* The receiver of `query_channel_range`:
*...
* - the first `reply_channel_range` message:
* - MUST set `first_blocknum` less than or equal to the
* `first_blocknum` in `query_channel_range`
* - MUST set `first_blocknum` plus `number_of_blocks` greater than
* `first_blocknum` in `query_channel_range`.
* - successive `reply_channel_range` message:
* - MUST have `first_blocknum` equal or greater than the previous
* `first_blocknum`.
* - MUST set `sync_complete` to `false` if this is not the final `reply_channel_range`.
* - the final `reply_channel_range` message:
* - MUST have `first_blocknum` plus `number_of_blocks` equal or
* greater than the `query_channel_range` `first_blocknum` plus
* `number_of_blocks`.
* - MUST set `sync_complete` to `true`.
*/
/* ie. They can be outside range we asked, but they must overlap! */
if (first_blocknum + number_of_blocks <= peer->range_first_blocknum
|| first_blocknum >= peer->range_end_blocknum) {
return towire_warningfmt(peer, NULL,
"reply_channel_range invalid %u+%u for query %u+%u",
first_blocknum, number_of_blocks,
peer->range_first_blocknum,
peer->range_end_blocknum
- peer->range_first_blocknum);
}
start = first_blocknum;
end = first_blocknum + number_of_blocks;
/* Trim to make it a subset of what we want. */
if (start < peer->range_first_blocknum)
start = peer->range_first_blocknum;
if (end > peer->range_end_blocknum)
end = peer->range_end_blocknum;
/* Have a seat. It's time for a history lesson in Rusty Screws Up.
*
* Part 1
* ------
* The original spec had a field called "complete" which meant
* "I believe I have complete knowledge of gossip", with the idea
* that lite nodes in future would not set this.
*
* But I chose a terrible name, and LND mis-implemented the spec,
* thinking this was an "end of replies". If they have multiple
* replies, set each one to the *whole* range, with complete=0 except
* the last.
*
* Here we try to accomodate that (pretend we make no progress
* until the end)! */
if (first_blocknum == peer->range_first_blocknum
&& first_blocknum + number_of_blocks == peer->range_end_blocknum
&& !sync_complete
&& tal_bytelen(msg) == 64046) {
status_unusual("Old LND reply_channel_range detected: result will be truncated!");
}
/*
* Part 2
* ------
* You were supposed to use the first_blocknum + number_of_blocks
* to tell when gossip was finished, with the rule being no replies
* could overlap, so you could say "I asked for blocks 100-199" and if
* you got a reply saying it covered blocks 50-150, you knew that you
* still had 49 blocks to receive.
*
* The field was renamed to `full_information`, and since everyone
* did it this way anyway, we insisted the replies be in
* non-overlapping ascending order.
*
* But LND didn't do this, and can actually overlap, since they just
* chop them up when they reach length, not by block boundary, so
* we had to allow that.
*
* Reading this implementation gave me envy: it was much simpler than
* backing out to a block boundary!
*
* And what if a single block had so many channel openings that you
* couldn't fit it in a single reply? (This was originally
* inconceivable, but with the addition of timestamps and checksums,
* is now possible).
*
* So we decided to make the lie into a truth. `full_information`
* was re-renamed to `sync_complete`, and once everyone has upgraded
* we can use that, rather than tallying the block numbers, to
* tell if replies are finished.
*/
err = append_range_reply(peer, scids, tlvs->timestamps_tlv);
if (err)
return err;
/* Credit peer for answering gossip, so seeker doesn't get upset:
* since scids are only 8 bytes, use a discount over normal gossip. */
peer_supplied_good_gossip(peer, tal_count(scids) / 20);
/* Old code used to set this to 1 all the time; not setting it implies
* we're talking to an upgraded node. */
if (!sync_complete) {
/* We no longer need old heuristic counter. */
peer->range_blocks_outstanding = 0;
return NULL;
}
/* FIXME: This "how many blocks do we have answers for?" heuristic
* can go away once everyone uses sync_complete properly. */
if (end - start < peer->range_blocks_outstanding) {
peer->range_blocks_outstanding -= end - start;
return NULL;
}
/* Clear these immediately in case cb want to queue more */
replies = tal_steal(tmpctx, peer->range_replies);
cb = peer->query_channel_range_cb;
peer->range_replies = NULL;
peer->query_channel_range_cb = NULL;
cb(peer, first_blocknum, number_of_blocks, replies);
return NULL;
}
/*~ When we ask about an array of short_channel_ids, we get all channel &
* node announcements and channel updates which the peer knows. There's an
* explicit end packet; this is needed to differentiate between 'I'm slow'
* and 'I don't know those channels'. */
const u8 *handle_reply_short_channel_ids_end(struct peer *peer, const u8 *msg)
{
struct bitcoin_blkid chain;
u8 complete;
if (!fromwire_reply_short_channel_ids_end(msg, &chain, &complete)) {
return towire_warningfmt(peer, NULL,
"Bad reply_short_channel_ids_end %s",
tal_hex(tmpctx, msg));
}
if (!bitcoin_blkid_eq(&chainparams->genesis_blockhash, &chain)) {
return towire_warningfmt(peer, NULL,
"reply_short_channel_ids_end for bad chain: %s",
tal_hex(tmpctx, msg));
}
if (!peer->scid_query_outstanding) {
return towire_warningfmt(peer, NULL,
"unexpected reply_short_channel_ids_end: %s",
tal_hex(tmpctx, msg));
}
peer->scid_query_outstanding = false;
if (peer->scid_query_cb)
peer->scid_query_cb(peer, complete);
/* All good, no error. */
return NULL;
}
/*~ Arbitrary ordering function of pubkeys.
*
* Note that we could use memcmp() here: even if they had somehow different
* bitwise representations for the same key, we copied them all from struct
* node which should make them unique. Even if not (say, a node vanished
* and reappeared) we'd just end up sending two node_announcement for the
* same node.
*/
static int pubkey_order(const struct node_id *k1,
const struct node_id *k2,
void *unused UNUSED)
{
return node_id_cmp(k1, k2);
}
static void uniquify_node_ids(struct node_id **ids)
{
size_t dst, src;
/* BOLT #7:
* - SHOULD avoid sending duplicate `node_announcements` in
* response to a single `query_short_channel_ids`.
*/
/* ccan/asort is a typesafe qsort wrapper: like most ccan modules
* it eschews exposing 'void *' pointers and ensures that the
* callback function and its arguments match types correctly. */
asort(*ids, tal_count(*ids), pubkey_order, NULL);
/* Compact the array */
for (dst = 0, src = 0; src < tal_count(*ids); src++) {
if (dst && node_id_eq(&(*ids)[dst-1], &(*ids)[src]))
continue;
(*ids)[dst++] = (*ids)[src];
}
/* And trim to length, so tal_count() gives correct answer. */
tal_resize(ids, dst);
}
/* We are fairly careful to avoid the peer DoSing us with channel queries:
* this routine sends information about a single short_channel_id, unless
* it's finished all of them. */
static bool maybe_send_query_responses_peer(struct peer *peer)
{
struct routing_state *rstate = peer->daemon->rstate;
size_t i, num;
bool sent = false;
/* BOLT #7:
*
* - MUST respond to each known `short_channel_id`:
*/
/* Search for next short_channel_id we know about. */
num = tal_count(peer->scid_queries);
for (i = peer->scid_query_idx; !sent && i < num; i++) {
struct chan *chan;
chan = get_channel(rstate, &peer->scid_queries[i]);
if (!chan || !is_chan_public(chan))
continue;
/* BOLT #7:
* - if bit 0 of `query_flag` is set:
* - MUST reply with a `channel_announcement`
*/
if (peer->scid_query_flags[i] & SCID_QF_ANNOUNCE) {
queue_peer_from_store(peer, &chan->bcast);
sent = true;
}
/* BOLT #7:
* - if bit 1 of `query_flag` is set and it has received a
* `channel_update` from `node_id_1`:
* - MUST reply with the latest `channel_update` for
* `node_id_1`
* - if bit 2 of `query_flag` is set and it has received a
* `channel_update` from `node_id_2`:
* - MUST reply with the latest `channel_update` for
* `node_id_2` */
if ((peer->scid_query_flags[i] & SCID_QF_UPDATE1)
&& is_halfchan_defined(&chan->half[0])) {
queue_peer_from_store(peer, &chan->half[0].bcast);
sent = true;
}
if ((peer->scid_query_flags[i] & SCID_QF_UPDATE2)
&& is_halfchan_defined(&chan->half[1])) {
queue_peer_from_store(peer, &chan->half[1].bcast);
sent = true;
}
/* BOLT #7:
* - if bit 3 of `query_flag` is set and it has received
* a `node_announcement` from `node_id_1`:
* - MUST reply with the latest `node_announcement` for
* `node_id_1`
* - if bit 4 of `query_flag` is set and it has received a
* `node_announcement` from `node_id_2`:
* - MUST reply with the latest `node_announcement` for
* `node_id_2` */
/* Save node ids for later transmission of node_announcement */
if (peer->scid_query_flags[i] & SCID_QF_NODE1)
tal_arr_expand(&peer->scid_query_nodes,
chan->nodes[0]->id);
if (peer->scid_query_flags[i] & SCID_QF_NODE2)
tal_arr_expand(&peer->scid_query_nodes,
chan->nodes[1]->id);
}
/* Just finished channels? Remove duplicate nodes. */
if (peer->scid_query_idx != num && i == num)
uniquify_node_ids(&peer->scid_query_nodes);
/* Update index for next time we're called. */
peer->scid_query_idx = i;
/* BOLT #7:
*
* - if the incoming message does not include `encoded_query_flags`:
* ...
* - MUST follow with any `node_announcement`s for each
* `channel_announcement`
* - otherwise:
* ...
* - if bit 3 of `query_flag` is set and it has received a
* `node_announcement` from `node_id_1`:
* - MUST reply with the latest `node_announcement` for
* `node_id_1`