sphinx: Creating copy of sphinx for new daemon

Keeping both the legacy daemon and the new daemon happy with the
restructure is a lot of work, so we just don't do it :-)

lightningd/sphinx.h

@@ -0,0 +1,140 @@
+#ifndef LIGHTNING_DAEMON_SPHINX_H
+#define LIGHTNING_DAEMON_SPHINX_H
+
+#include "config.h"
+#include "bitcoin/privkey.h"
+#include "bitcoin/pubkey.h"
+
+#include <ccan/short_types/short_types.h>
+#include <ccan/tal/tal.h>
+#include <secp256k1.h>
+#include <sodium/randombytes.h>
+
+#define SECURITY_PARAMETER 20
+#define NUM_MAX_HOPS 20
+#define HOP_PAYLOAD_SIZE 20
+#define TOTAL_HOP_PAYLOAD_SIZE (NUM_MAX_HOPS * HOP_PAYLOAD_SIZE)
+#define ROUTING_INFO_SIZE (2 * NUM_MAX_HOPS * SECURITY_PARAMETER)
+#define TOTAL_PACKET_SIZE (1 + 33 + SECURITY_PARAMETER + ROUTING_INFO_SIZE + \
+			   TOTAL_HOP_PAYLOAD_SIZE)
+
+struct onionpacket {
+	/* Cleartext information */
+	u8 version;
+	u8 nexthop[20];
+	u8 mac[20];
+	secp256k1_pubkey ephemeralkey;
+
+	/* Encrypted information */
+	u8 routinginfo[ROUTING_INFO_SIZE];
+	u8 hoppayloads[TOTAL_HOP_PAYLOAD_SIZE];
+};
+
+enum route_next_case {
+	ONION_END = 0,
+	ONION_FORWARD = 1,
+};
+
+/* BOLT #4:
+ *
+ * The format of the per-hop-payload for a version 0 packet is as follows:
+```
++----------------+--------------------------+-------------------------------+--------------------------------------------+
+| realm (1 byte) | amt_to_forward (8 bytes) | outgoing_cltv_value (4 bytes) | unused_with_v0_version_on_header (7 bytes) |
++----------------+--------------------------+-------------------------------+--------------------------------------------+
+```
+*/
+struct hoppayload {
+	u8 realm;
+	u64 amt_to_forward;
+	u32 outgoing_cltv_value;
+	u8 unused_with_v0_version_on_header[7];
+};
+
+struct route_step {
+	enum route_next_case nextcase;
+	struct onionpacket *next;
+	struct hoppayload *hoppayload;
+};
+
+/**
+ * create_onionpacket - Create a new onionpacket that can be routed
+ * over a path of intermediate nodes.
+ *
+ * @ctx: tal context to allocate from
+ * @path: public keys of nodes along the path.
+ * @hoppayloads: payloads destined for individual hosts (limited to
+ *    HOP_PAYLOAD_SIZE bytes)
+ * @num_hops: path length in nodes
+ * @sessionkey: 20 byte random session key to derive secrets from
+ * @assocdata: associated data to commit to in HMACs
+ * @assocdatalen: length of the assocdata
+ */
+struct onionpacket *create_onionpacket(
+	const tal_t * ctx,
+	struct pubkey path[],
+	struct hoppayload hoppayloads[],
+	const u8 * sessionkey,
+	const u8 *assocdata,
+	const size_t assocdatalen
+	);
+
+/**
+ * onion_shared_secret - calculate ECDH shared secret between nodes.
+ *
+ * @secret: the shared secret (32 bytes long)
+ * @pubkey: the public key of the other node
+ * @privkey: the private key of this node (32 bytes long)
+ */
+bool onion_shared_secret(
+	u8 *secret,
+	const struct onionpacket *packet,
+	const struct privkey *privkey);
+
+/**
+ * process_onionpacket - process an incoming packet by stripping one
+ * onion layer and return the packet for the next hop.
+ *
+ * @ctx: tal context to allocate from
+ * @packet: incoming packet being processed
+ * @shared_secret: the result of onion_shared_secret.
+ * @hoppayload: the per-hop payload destined for the processing node.
+ * @assocdata: associated data to commit to in HMACs
+ * @assocdatalen: length of the assocdata
+ */
+struct route_step *process_onionpacket(
+	const tal_t * ctx,
+	const struct onionpacket *packet,
+	const u8 *shared_secret,
+	const u8 *assocdata,
+	const size_t assocdatalen
+	);
+
+/**
+ * serialize_onionpacket - Serialize an onionpacket to a buffer.
+ *
+ * @ctx: tal context to allocate from
+ * @packet: the packet to serialize
+ */
+u8 *serialize_onionpacket(
+	const tal_t *ctx,
+	const struct onionpacket *packet);
+
+/**
+ * parese_onionpacket - Parse an onionpacket from a buffer.
+ *
+ * @ctx: tal context to allocate from
+ * @src: buffer to read the packet from
+ * @srclen: length of the @src
+ */
+struct onionpacket *parse_onionpacket(
+	const tal_t *ctx,
+	const void *src,
+	const size_t srclen
+	);
+
+void pubkey_hash160(
+	u8 *dst,
+	const struct pubkey *pubkey);
+
+#endif /* LIGHTNING_DAEMON_SPHINX_H */