141 lines
3.8 KiB
C
141 lines
3.8 KiB
C
#ifndef LIGHTNING_DAEMON_SPHINX_H
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#define LIGHTNING_DAEMON_SPHINX_H
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#include "config.h"
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#include "bitcoin/privkey.h"
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#include "bitcoin/pubkey.h"
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#include <ccan/short_types/short_types.h>
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#include <ccan/tal/tal.h>
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#include <secp256k1.h>
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#include <sodium/randombytes.h>
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#define SECURITY_PARAMETER 20
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#define NUM_MAX_HOPS 20
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#define HOP_PAYLOAD_SIZE 20
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#define TOTAL_HOP_PAYLOAD_SIZE (NUM_MAX_HOPS * HOP_PAYLOAD_SIZE)
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#define ROUTING_INFO_SIZE (2 * NUM_MAX_HOPS * SECURITY_PARAMETER)
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#define TOTAL_PACKET_SIZE (1 + 33 + SECURITY_PARAMETER + ROUTING_INFO_SIZE + \
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TOTAL_HOP_PAYLOAD_SIZE)
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struct onionpacket {
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/* Cleartext information */
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u8 version;
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u8 nexthop[20];
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u8 mac[20];
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secp256k1_pubkey ephemeralkey;
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/* Encrypted information */
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u8 routinginfo[ROUTING_INFO_SIZE];
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u8 hoppayloads[TOTAL_HOP_PAYLOAD_SIZE];
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};
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enum route_next_case {
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ONION_END = 0,
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ONION_FORWARD = 1,
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};
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/* BOLT #4:
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*
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* The format of the per-hop-payload for a version 0 packet is as follows:
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```
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+----------------+--------------------------+-------------------------------+--------------------------------------------+
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| realm (1 byte) | amt_to_forward (8 bytes) | outgoing_cltv_value (4 bytes) | unused_with_v0_version_on_header (7 bytes) |
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+----------------+--------------------------+-------------------------------+--------------------------------------------+
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```
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*/
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struct hoppayload {
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u8 realm;
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u64 amt_to_forward;
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u32 outgoing_cltv_value;
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u8 unused_with_v0_version_on_header[7];
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};
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struct route_step {
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enum route_next_case nextcase;
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struct onionpacket *next;
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struct hoppayload *hoppayload;
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};
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/**
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* create_onionpacket - Create a new onionpacket that can be routed
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* over a path of intermediate nodes.
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*
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* @ctx: tal context to allocate from
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* @path: public keys of nodes along the path.
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* @hoppayloads: payloads destined for individual hosts (limited to
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* HOP_PAYLOAD_SIZE bytes)
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* @num_hops: path length in nodes
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* @sessionkey: 20 byte random session key to derive secrets from
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* @assocdata: associated data to commit to in HMACs
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* @assocdatalen: length of the assocdata
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*/
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struct onionpacket *create_onionpacket(
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const tal_t * ctx,
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struct pubkey path[],
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struct hoppayload hoppayloads[],
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const u8 * sessionkey,
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const u8 *assocdata,
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const size_t assocdatalen
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);
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/**
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* onion_shared_secret - calculate ECDH shared secret between nodes.
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*
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* @secret: the shared secret (32 bytes long)
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* @pubkey: the public key of the other node
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* @privkey: the private key of this node (32 bytes long)
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*/
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bool onion_shared_secret(
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u8 *secret,
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const struct onionpacket *packet,
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const struct privkey *privkey);
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/**
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* process_onionpacket - process an incoming packet by stripping one
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* onion layer and return the packet for the next hop.
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*
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* @ctx: tal context to allocate from
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* @packet: incoming packet being processed
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* @shared_secret: the result of onion_shared_secret.
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* @hoppayload: the per-hop payload destined for the processing node.
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* @assocdata: associated data to commit to in HMACs
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* @assocdatalen: length of the assocdata
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*/
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struct route_step *process_onionpacket(
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const tal_t * ctx,
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const struct onionpacket *packet,
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const u8 *shared_secret,
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const u8 *assocdata,
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const size_t assocdatalen
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);
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/**
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* serialize_onionpacket - Serialize an onionpacket to a buffer.
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*
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* @ctx: tal context to allocate from
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* @packet: the packet to serialize
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*/
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u8 *serialize_onionpacket(
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const tal_t *ctx,
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const struct onionpacket *packet);
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/**
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* parese_onionpacket - Parse an onionpacket from a buffer.
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*
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* @ctx: tal context to allocate from
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* @src: buffer to read the packet from
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* @srclen: length of the @src
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*/
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struct onionpacket *parse_onionpacket(
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const tal_t *ctx,
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const void *src,
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const size_t srclen
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);
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void pubkey_hash160(
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u8 *dst,
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const struct pubkey *pubkey);
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#endif /* LIGHTNING_DAEMON_SPHINX_H */
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