// The median hop CLTV expiry delta currently seen in the network.
const MEDIAN_HOP_CLTV_EXPIRY_DELTA: u32 = 40;
+/// Estimated maximum number of hops that can be included in a payment path. May be inaccurate if
+/// payment metadata, custom TLVs, or blinded paths are included in the payment.
// During routing, we only consider paths shorter than our maximum length estimate.
// In the TLV onion format, there is no fixed maximum length, but the `hop_payloads`
// field is always 1300 bytes. As the `tlv_payload` for each hop may vary in length, we have to
// (payment_secret and total_msat) = 93 bytes for the final hop.
// Since the length of the potentially included `payment_metadata` is unknown to us, we round
// down from (1300-93) / 61 = 19.78... to arrive at a conservative estimate of 19.
-const MAX_PATH_LENGTH_ESTIMATE: u8 = 19;
+pub const MAX_PATH_LENGTH_ESTIMATE: u8 = 19;
/// Information used to route a payment.
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
/// Defaults to [`DEFAULT_MAX_PATH_COUNT`].
pub max_path_count: u8,
+ /// The maximum number of [`Path::hops`] in any returned path.
+ /// Defaults to [`MAX_PATH_LENGTH_ESTIMATE`].
+ pub max_path_length: u8,
+
/// Selects the maximum share of a channel's total capacity which will be sent over a channel,
/// as a power of 1/2. A higher value prefers to send the payment using more MPP parts whereas
/// a lower value prefers to send larger MPP parts, potentially saturating channels and
(8, *blinded_hints, optional_vec),
(9, self.payee.final_cltv_expiry_delta(), option),
(11, self.previously_failed_blinded_path_idxs, required_vec),
+ (13, self.max_path_length, required),
});
Ok(())
}
(8, blinded_route_hints, optional_vec),
(9, final_cltv_expiry_delta, (default_value, default_final_cltv_expiry_delta)),
(11, previously_failed_blinded_path_idxs, optional_vec),
+ (13, max_path_length, (default_value, MAX_PATH_LENGTH_ESTIMATE)),
});
let blinded_route_hints = blinded_route_hints.unwrap_or(vec![]);
let payee = if blinded_route_hints.len() != 0 {
expiry_time,
previously_failed_channels: previously_failed_channels.unwrap_or(Vec::new()),
previously_failed_blinded_path_idxs: previously_failed_blinded_path_idxs.unwrap_or(Vec::new()),
+ max_path_length: _init_tlv_based_struct_field!(max_path_length, (default_value, unused)),
})
}
}
expiry_time: None,
max_total_cltv_expiry_delta: DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA,
max_path_count: DEFAULT_MAX_PATH_COUNT,
+ max_path_length: MAX_PATH_LENGTH_ESTIMATE,
max_channel_saturation_power_of_half: DEFAULT_MAX_CHANNEL_SATURATION_POW_HALF,
previously_failed_channels: Vec::new(),
previously_failed_blinded_path_idxs: Vec::new(),
expiry_time: None,
max_total_cltv_expiry_delta: DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA,
max_path_count: DEFAULT_MAX_PATH_COUNT,
+ max_path_length: MAX_PATH_LENGTH_ESTIMATE,
max_channel_saturation_power_of_half: DEFAULT_MAX_CHANNEL_SATURATION_POW_HALF,
previously_failed_channels: Vec::new(),
previously_failed_blinded_path_idxs: Vec::new(),