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rgb-cln/gossipd/gossip_generation.c

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/* Routines to make our own gossip messages. Not as in "we're the gossip
* generation, man!" */
#include <ccan/mem/mem.h>
#include <common/features.h>
#include <common/memleak.h>
#include <common/status.h>
#include <common/timeout.h>
#include <common/type_to_string.h>
#include <common/utils.h>
#include <common/wireaddr.h>
#include <errno.h>
#include <gossipd/gen_gossip_peerd_wire.h>
#include <gossipd/gossip_generation.h>
#include <gossipd/gossip_store.h>
#include <gossipd/gossipd.h>
#include <hsmd/gen_hsm_wire.h>
#include <wire/gen_peer_wire.h>
#include <wire/wire_sync.h>
/* Create a node_announcement with the given signature. It may be NULL in the
* case we need to create a provisional announcement for the HSM to sign.
* This is called twice: once with the dummy signature to get it signed and a
* second time to build the full packet with the signature. The timestamp is
* handed in rather than using time_now() internally, since that could change
* between the dummy creation and the call with a signature. */
static u8 *create_node_announcement(const tal_t *ctx, struct daemon *daemon,
const secp256k1_ecdsa_signature *sig,
u32 timestamp)
{
u8 *addresses = tal_arr(tmpctx, u8, 0);
u8 *announcement;
size_t i;
if (!sig)
sig = talz(tmpctx, secp256k1_ecdsa_signature);
for (i = 0; i < tal_count(daemon->announcable); i++)
towire_wireaddr(&addresses, &daemon->announcable[i]);
announcement =
towire_node_announcement(ctx, sig,
daemon->our_features->bits
[NODE_ANNOUNCE_FEATURE],
timestamp,
&daemon->id, daemon->rgb, daemon->alias,
addresses);
return announcement;
}
/* Helper to get non-signature, non-timestamp parts of (valid!) channel_update */
void get_cupdate_parts(const u8 *channel_update,
const u8 *parts[2],
size_t sizes[2])
{
/* BOLT #7:
*
* 1. type: 258 (`channel_update`)
* 2. data:
* * [`signature`:`signature`]
* * [`chain_hash`:`chain_hash`]
* * [`short_channel_id`:`short_channel_id`]
* * [`u32`:`timestamp`]
*...
*/
/* Note: 2 bytes for `type` field */
/* We already checked it's valid before accepting */
assert(tal_count(channel_update) > 2 + 64 + 32 + 8 + 4);
parts[0] = channel_update + 2 + 64;
sizes[0] = 32 + 8;
parts[1] = channel_update + 2 + 64 + 32 + 8 + 4;
sizes[1] = tal_count(channel_update) - (64 + 2 + 32 + 8 + 4);
}
/* Is this channel_update different from prev (not sigs and timestamps)? */
bool cupdate_different(struct gossip_store *gs,
const struct half_chan *hc,
const u8 *cupdate)
{
const u8 *oparts[2], *nparts[2];
size_t osizes[2], nsizes[2];
const u8 *orig;
/* Get last one we have. */
orig = gossip_store_get(tmpctx, gs, hc->bcast.index);
get_cupdate_parts(orig, oparts, osizes);
get_cupdate_parts(cupdate, nparts, nsizes);
return !memeq(oparts[0], osizes[0], nparts[0], nsizes[0])
|| !memeq(oparts[1], osizes[1], nparts[1], nsizes[1]);
}
/* Get non-signature, non-timestamp parts of (valid!) node_announcement */
static void get_nannounce_parts(const u8 *node_announcement,
const u8 *parts[2],
size_t sizes[2])
{
size_t len;
const u8 *flen;
/* BOLT #7:
*
* 1. type: 257 (`node_announcement`)
* 2. data:
* * [`signature`:`signature`]
* * [`u16`:`flen`]
* * [`flen*byte`:`features`]
* * [`u32`:`timestamp`]
*...
*/
/* Note: 2 bytes for `type` field */
/* We already checked it's valid before accepting */
assert(tal_count(node_announcement) > 2 + 64);
parts[0] = node_announcement + 2 + 64;
/* Read flen to get size */
flen = parts[0];
len = tal_count(node_announcement) - (2 + 64);
sizes[0] = 2 + fromwire_u16(&flen, &len);
assert(flen != NULL && len >= 4);
parts[1] = node_announcement + 2 + 64 + sizes[0] + 4;
sizes[1] = tal_count(node_announcement) - (2 + 64 + sizes[0] + 4);
}
/* Is this node_announcement different from prev (not sigs and timestamps)? */
bool nannounce_different(struct gossip_store *gs,
const struct node *node,
const u8 *nannounce)
{
const u8 *oparts[2], *nparts[2];
size_t osizes[2], nsizes[2];
const u8 *orig;
/* Get last one we have. */
orig = gossip_store_get(tmpctx, gs, node->bcast.index);
get_nannounce_parts(orig, oparts, osizes);
get_nannounce_parts(nannounce, nparts, nsizes);
return !memeq(oparts[0], osizes[0], nparts[0], nsizes[0])
|| !memeq(oparts[1], osizes[1], nparts[1], nsizes[1]);
}
/* This routine created a `node_announcement` for our node, and hands it to
* the routing.c code like any other `node_announcement`. Such announcements
* are only accepted if there is an announced channel associated with that node
* (to prevent spam), so we only call this once we've announced a channel. */
static void update_own_node_announcement(struct daemon *daemon)
{
u32 timestamp = gossip_time_now(daemon->rstate).ts.tv_sec;
secp256k1_ecdsa_signature sig;
u8 *msg, *nannounce, *err;
struct node *self = get_node(daemon->rstate, &daemon->id);
/* Discard existing timer. */
daemon->node_announce_timer = tal_free(daemon->node_announce_timer);
/* If we ever use set-based propagation, ensuring the toggle the lower
* bit in consecutive timestamps makes it more robust. */
if (self && self->bcast.index
&& (timestamp & 1) == (self->bcast.timestamp & 1))
timestamp++;
/* Make unsigned announcement. */
nannounce = create_node_announcement(tmpctx, daemon, NULL, timestamp);
/* If it's the same as the previous, nothing to do. */
if (self && self->bcast.index) {
u32 next;
if (!nannounce_different(daemon->rstate->gs, self, nannounce))
return;
/* BOLT #7:
*
* The origin node:
* - MUST set `timestamp` to be greater than that of any
* previous `node_announcement` it has previously created.
*/
/* We do better: never send them within more than 5 minutes. */
next = self->bcast.timestamp
+ GOSSIP_MIN_INTERVAL(daemon->rstate->dev_fast_gossip);
if (timestamp < next) {
status_debug("node_announcement: delaying %u secs",
next - timestamp);
daemon->node_announce_timer
= new_reltimer(&daemon->timers,
daemon,
time_from_sec(next - timestamp),
update_own_node_announcement,
daemon);
return;
}
}
/* Ask hsmd to sign it (synchronous) */
if (!wire_sync_write(HSM_FD, take(towire_hsm_node_announcement_sig_req(NULL, nannounce))))
status_failed(STATUS_FAIL_MASTER_IO, "Could not write to HSM: %s", strerror(errno));
msg = wire_sync_read(tmpctx, HSM_FD);
if (!fromwire_hsm_node_announcement_sig_reply(msg, &sig))
status_failed(STATUS_FAIL_MASTER_IO, "HSM returned an invalid node_announcement sig");
/* We got the signature for our provisional node_announcement back
* from the HSM, create the real announcement and forward it to
* gossipd so it can take care of forwarding it. */
nannounce = create_node_announcement(NULL, daemon, &sig, timestamp);
/* This injects it into the routing code in routing.c; it should not
* reject it! */
err = handle_node_announcement(daemon->rstate, take(nannounce),
NULL, NULL);
if (err)
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"rejected own node announcement: %s",
tal_hex(tmpctx, err));
}
/* Should we announce our own node? Called at strategic places. */
void maybe_send_own_node_announce(struct daemon *daemon)
{
/* We keep an internal flag in the routing code to say we've announced
* a local channel. The alternative would be to have it make a
* callback, but when we start up we don't want to make multiple
* announcments, so we use this approach for now. */
if (!daemon->rstate->local_channel_announced)
return;
update_own_node_announcement(daemon);
daemon->rstate->local_channel_announced = false;
}
/* Our timer callbacks take a single argument, so we marshall everything
* we need into this structure: */
struct local_cupdate {
struct daemon *daemon;
struct local_chan *local_chan;
bool disable;
bool even_if_identical;
u16 cltv_expiry_delta;
struct amount_msat htlc_minimum, htlc_maximum;
u32 fee_base_msat, fee_proportional_millionths;
};
/* This generates a `channel_update` message for one of our channels. We do
* this here, rather than in `channeld` because we (may) need to do it
* ourselves anyway if channeld dies, or when we refresh it once a week,
* and so we can avoid creating redundant ones. */
static void update_local_channel(struct local_cupdate *lc /* frees! */)
{
struct daemon *daemon = lc->daemon;
secp256k1_ecdsa_signature dummy_sig;
u8 *update, *msg;
u32 timestamp = gossip_time_now(daemon->rstate).ts.tv_sec, next;
u8 message_flags, channel_flags;
struct chan *chan = lc->local_chan->chan;
struct half_chan *hc;
const int direction = lc->local_chan->direction;
/* Discard existing timer. */
lc->local_chan->channel_update_timer
= tal_free(lc->local_chan->channel_update_timer);
/* So valgrind doesn't complain */
memset(&dummy_sig, 0, sizeof(dummy_sig));
/* Create an unsigned channel_update: we backdate enables, so
* we can always send a disable in an emergency. */
if (!lc->disable)
timestamp -= GOSSIP_MIN_INTERVAL(daemon->rstate->dev_fast_gossip);
/* BOLT #7:
*
* The `channel_flags` bitfield is used to indicate the direction of
* the channel: it identifies the node that this update originated
* from and signals various options concerning the channel. The
* following table specifies the meaning of its individual bits:
*
* | Bit Position | Name | Meaning |
* | ------------- | ----------- | -------------------------------- |
* | 0 | `direction` | Direction this update refers to. |
* | 1 | `disable` | Disable the channel. |
*/
channel_flags = direction;
if (lc->disable)
channel_flags |= ROUTING_FLAGS_DISABLED;
/* BOLT #7:
*
* The `message_flags` bitfield is used to indicate the presence of
* optional fields in the `channel_update` message:
*
*| Bit Position | Name | Field |
*...
*| 0 | `option_channel_htlc_max` | `htlc_maximum_msat` |
*/
message_flags = 0 | ROUTING_OPT_HTLC_MAX_MSAT;
/* Convenience variable. */
hc = &chan->half[direction];
/* If we ever use set-based propagation, ensuring the toggle
* the lower bit in consecutive timestamps makes it more
* robust. */
if (is_halfchan_defined(hc)
&& (timestamp & 1) == (hc->bcast.timestamp & 1))
timestamp++;
/* We create an update with a dummy signature, and hand to hsmd to get
* it signed. */
update = towire_channel_update_option_channel_htlc_max(tmpctx, &dummy_sig,
&chainparams->genesis_blockhash,
&chan->scid,
timestamp,
message_flags, channel_flags,
lc->cltv_expiry_delta,
lc->htlc_minimum,
lc->fee_base_msat,
lc->fee_proportional_millionths,
lc->htlc_maximum);
if (is_halfchan_defined(hc)) {
/* Suppress duplicates. */
if (!lc->even_if_identical
&& !cupdate_different(daemon->rstate->gs, hc, update)) {
tal_free(lc);
return;
}
/* Is it too soon to send another update? */
next = hc->bcast.timestamp
+ GOSSIP_MIN_INTERVAL(daemon->rstate->dev_fast_gossip);
if (timestamp < next) {
status_debug("channel_update %s/%u: delaying %u secs",
type_to_string(tmpctx,
struct short_channel_id,
&chan->scid),
direction,
next - timestamp);
lc->local_chan->channel_update_timer
= new_reltimer(&daemon->timers, lc,
time_from_sec(next - timestamp),
update_local_channel,
lc);
/* If local chan vanishes, so does update, and timer. */
notleak(tal_steal(lc->local_chan, lc));
return;
}
}
/* Note that we treat the hsmd as synchronous. This is simple (no
* callback hell)!, but may need to change to async if we ever want
* remote HSMs */
if (!wire_sync_write(HSM_FD,
towire_hsm_cupdate_sig_req(tmpctx, update))) {
status_failed(STATUS_FAIL_HSM_IO, "Writing cupdate_sig_req: %s",
strerror(errno));
}
msg = wire_sync_read(tmpctx, HSM_FD);
if (!msg || !fromwire_hsm_cupdate_sig_reply(tmpctx, msg, &update)) {
status_failed(STATUS_FAIL_HSM_IO,
"Reading cupdate_sig_req: %s",
strerror(errno));
}
/* BOLT #7:
*
* The origin node:
*...
* - MAY create a `channel_update` to communicate the channel parameters to the
* channel peer, even though the channel has not yet been announced (i.e. the
* `announce_channel` bit was not set).
*/
if (!is_chan_public(chan)) {
/* handle_channel_update will not put private updates in the
* broadcast list, but we send it direct to the peer (if we
* have one connected) now */
struct peer *peer = find_peer(daemon,
&chan->nodes[!direction]->id);
if (peer)
queue_peer_msg(peer, update);
}
/* We feed it into routing.c like any other channel_update; it may
* discard it (eg. non-public channel), but it should not complain
* about it being invalid! __func__ is a magic C constant which
* expands to this function name. */
msg = handle_channel_update(daemon->rstate, update,
find_peer(daemon,
&chan->nodes[!direction]->id),
NULL);
if (msg)
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"%s: rejected local channel update %s: %s",
__func__,
/* Normally we must not touch something taken()
* but we're in deep trouble anyway, and
* handle_channel_update only tal_steals onto
* tmpctx, so it's actually OK. */
tal_hex(tmpctx, update),
tal_hex(tmpctx, msg));
tal_free(lc);
}
/* This is a refresh of a local channel: sends an update if one is needed. */
void refresh_local_channel(struct daemon *daemon,
struct local_chan *local_chan,
bool even_if_identical)
{
const struct half_chan *hc;
struct local_cupdate *lc;
hc = &local_chan->chan->half[local_chan->direction];
/* Don't generate a channel_update for an uninitialized channel. */
if (!is_halfchan_defined(hc))
return;
lc = tal(NULL, struct local_cupdate);
lc->daemon = daemon;
lc->local_chan = local_chan;
lc->even_if_identical = even_if_identical;
lc->disable = (hc->channel_flags & ROUTING_FLAGS_DISABLED)
|| local_chan->local_disabled;
lc->cltv_expiry_delta = hc->delay;
lc->htlc_minimum = hc->htlc_minimum;
lc->htlc_maximum = hc->htlc_maximum;
lc->fee_base_msat = hc->base_fee;
lc->fee_proportional_millionths = hc->proportional_fee;
update_local_channel(lc);
}
/* channeld asks us to update the local channel. */
bool handle_local_channel_update(struct daemon *daemon,
const struct node_id *src,
const u8 *msg)
{
struct short_channel_id scid;
struct local_cupdate *lc = tal(tmpctx, struct local_cupdate);
lc->daemon = daemon;
lc->even_if_identical = false;
/* FIXME: We should get scid from lightningd when setting up the
* connection, so no per-peer daemon can mess with channels other than
* its own! */
if (!fromwire_gossipd_local_channel_update(msg,
&scid,
&lc->disable,
&lc->cltv_expiry_delta,
&lc->htlc_minimum,
&lc->fee_base_msat,
&lc->fee_proportional_millionths,
&lc->htlc_maximum)) {
status_peer_broken(src, "bad local_channel_update %s",
tal_hex(tmpctx, msg));
return false;
}
lc->local_chan = local_chan_map_get(&daemon->rstate->local_chan_map,
&scid);
/* Can theoretically happen if channel just closed. */
if (!lc->local_chan) {
status_peer_debug(src, "local_channel_update for unknown %s",
type_to_string(tmpctx, struct short_channel_id,
&scid));
return true;
}
/* Remove soft local_disabled flag, if they're marking it enabled. */
if (!lc->disable)
local_enable_chan(daemon->rstate, lc->local_chan->chan);
/* Apply the update they told us */
update_local_channel(tal_steal(NULL, lc));
return true;
}
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