lightningd: add delforward command.

Changelog-Added: JSON-RPC: `delforward` command to delete listforwards entries.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/jsonrpc_errors.h

@@ -104,6 +104,9 @@ enum jsonrpc_errcode {
 	/* Errors from signmessage command */
 	SIGNMESSAGE_PUBKEY_NOT_FOUND = 1301,
 
+	/* Errors from delforward command */
+	DELFORWARD_NOT_FOUND = 1401,
+
 	/* Errors from wait* commands */
 	WAIT_TIMEOUT = 2000,
 };

doc/Makefile

@@ -28,6 +28,7 @@ MANPAGES := doc/lightning-cli.1 \
 	doc/lightning-decode.7 \
 	doc/lightning-deldatastore.7 \
 	doc/lightning-delexpiredinvoice.7 \
+	doc/lightning-delforward.7 \
 	doc/lightning-delinvoice.7 \
 	doc/lightning-delpay.7 \
 	doc/lightning-disableoffer.7 \

doc/index.rst

@@ -51,6 +51,7 @@ Core Lightning Documentation
    lightning-decodepay <lightning-decodepay.7.md>
    lightning-deldatastore <lightning-deldatastore.7.md>
    lightning-delexpiredinvoice <lightning-delexpiredinvoice.7.md>
+   lightning-delforward <lightning-delforward.7.md>
    lightning-delinvoice <lightning-delinvoice.7.md>
    lightning-delpay <lightning-delpay.7.md>
    lightning-disableoffer <lightning-disableoffer.7.md>

doc/lightning-delforward.7.md

@@ -0,0 +1,53 @@
+lightning-delforward -- Command for removing a forwarding entry
+===============================================================
+
+SYNOPSIS
+--------
+
+**delforward** *in_channel* *in_htlc_id* *status*
+
+DESCRIPTION
+-----------
+
+The **delforward** RPC command removes a single forward from **listforwards**,
+using the uniquely-identifying *in_channel* and *in_htlc_id* (and, as a sanity
+check, the *status*) given by that command.
+
+This command is mainly used by the *autoclean* plugin (see lightningd-config(7)),
+As these database entries are only kept for your own analysis, removing them
+has no effect on the running of your node.
+
+You cannot delete forwards which have status *offered* (i.e. are
+currently active).
+
+RETURN VALUE
+------------
+
+[comment]: # (GENERATE-FROM-SCHEMA-START)
+On success, an empty object is returned.
+
+[comment]: # (GENERATE-FROM-SCHEMA-END)
+
+ERRORS
+------
+
+The following errors may be reported:
+
+- 1401: The forward specified does not exist.
+
+AUTHOR
+------
+
+Rusty Russell <<rusty@rustcorp.com.au>> is mainly responsible.
+
+SEE ALSO
+--------
+
+lightning-autoclean(7)
+
+RESOURCES
+---------
+
+Main web site: <https://github.com/ElementsProject/lightning>
+
+[comment]: # ( SHA256STAMP:200de829c6635242cb2dd8ec0650c2fa8f5fcbf413f4a704884516df80492fcb)

doc/schemas/delforward.request.json

@@ -0,0 +1,21 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "type": "object",
+  "required": [],
+  "properties": {
+    "in_channel": {
+      "type": "short_channel_id"
+    },
+    "in_htlc_id": {
+      "type": "u64"
+    },
+    "status": {
+      "type": "string",
+      "enum": [
+        "settled",
+        "local_failed",
+        "failed"
+      ]
+    }
+  }
+}

doc/schemas/delforward.schema.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "type": "object",
+  "additionalProperties": false,
+  "required": [],
+  "properties": {}
+}

lightningd/peer_htlcs.c

@@ -2895,6 +2895,65 @@ static const struct json_command listforwards_command = {
 };
 AUTODATA(json_command, &listforwards_command);
 
+static struct command_result *param_forward_delstatus(struct command *cmd,
+						      const char *name,
+						      const char *buffer,
+						      const jsmntok_t *tok,
+						      enum forward_status **status)
+{
+	struct command_result *ret;
+
+	ret = param_forward_status(cmd, name, buffer, tok, status);
+	if (ret)
+		return ret;
+
+	switch (**status) {
+	case FORWARD_OFFERED:
+		return command_fail_badparam(cmd, name, buffer, tok,
+					     "delforward status cannot be offered");
+	case FORWARD_ANY:
+		return command_fail_badparam(cmd, name, buffer, tok,
+					     "delforward status cannot be any");
+	case FORWARD_SETTLED:
+	case FORWARD_FAILED:
+	case FORWARD_LOCAL_FAILED:
+		return NULL;
+	}
+	abort();
+}
+
+static struct command_result *json_delforward(struct command *cmd,
+					      const char *buffer,
+					      const jsmntok_t *obj UNNEEDED,
+					      const jsmntok_t *params)
+{
+	struct short_channel_id *chan_in;
+	u64 *htlc_id;
+	enum forward_status *status;
+
+	if (!param(cmd, buffer, params,
+		   p_req("in_channel", param_short_channel_id, &chan_in),
+		   p_req("in_htlc_id", param_u64, &htlc_id),
+		   p_req("status", param_forward_delstatus, &status),
+		   NULL))
+		return command_param_failed();
+
+	if (!wallet_forward_delete(cmd->ld->wallet,
+				   chan_in, *htlc_id, *status))
+		return command_fail(cmd, DELFORWARD_NOT_FOUND,
+				    "Could not find that forward");
+
+	return command_success(cmd, json_stream_success(cmd));
+}
+
+static const struct json_command delforward_command = {
+	"delforward",
+	"channels",
+	json_delforward,
+	"Delete a forwarded payment by [in_channel], [in_htlc_id] and [status]"
+};
+AUTODATA(json_command, &delforward_command);
+
 static struct command_result *param_channel(struct command *cmd,
 					    const char *name,
 					    const char *buffer,

tests/test_misc.py

@@ -2493,6 +2493,17 @@ def test_listforwards_and_listhtlcs(node_factory, bitcoind):
     # But forwards are not forgotten!
     assert l2.rpc.listforwards()['forwards'] == all_forwards
 
+    # Now try delforward!
+    with pytest.raises(RpcError, match="Could not find that forward") as exc_info:
+        l2.rpc.delforward(in_channel=c12, in_htlc_id=3, status='settled')
+    # static const errcode_t DELFORWARD_NOT_FOUND = 1401;
+    assert exc_info.value.error['code'] == 1401
+
+    l2.rpc.delforward(in_channel=c12, in_htlc_id=0, status='settled')
+    l2.rpc.delforward(in_channel=c12, in_htlc_id=1, status='settled')
+    l2.rpc.delforward(in_channel=c12, in_htlc_id=2, status='local_failed')
+    assert l2.rpc.listforwards() == {'forwards': []}
+
 
 @pytest.mark.openchannel('v1')
 def test_version_reexec(node_factory, bitcoind):

wallet/test/run-wallet.c

@@ -616,6 +616,11 @@ struct command_result *param_short_channel_id(struct command *cmd UNNEEDED,
 					      const jsmntok_t *tok UNNEEDED,
 					      struct short_channel_id **scid UNNEEDED)
 { fprintf(stderr, "param_short_channel_id called!\n"); abort(); }
+/* Generated stub for param_u64 */
+struct command_result *param_u64(struct command *cmd UNNEEDED, const char *name UNNEEDED,
+				 const char *buffer UNNEEDED, const jsmntok_t *tok UNNEEDED,
+				 uint64_t **num UNNEEDED)
+{ fprintf(stderr, "param_u64 called!\n"); abort(); }
 /* Generated stub for parse_onionpacket */
 struct onionpacket *parse_onionpacket(const tal_t *ctx UNNEEDED,
 				      const u8 *src UNNEEDED,

wallet/wallet.c

@@ -4663,6 +4663,29 @@ const struct forwarding *wallet_forwarded_payments_get(struct wallet *w,
 	return results;
 }
 
+bool wallet_forward_delete(struct wallet *w,
+			   const struct short_channel_id *chan_in,
+			   u64 htlc_id,
+			   enum forward_status state)
+{
+	struct db_stmt *stmt;
+	bool changed;
+
+	stmt = db_prepare_v2(w->db,
+			     SQL("DELETE FROM forwards"
+				 " WHERE in_channel_scid = ?"
+				 " AND in_htlc_id = ?"
+				 " AND state = ?"));
+	db_bind_scid(stmt, 0, chan_in);
+	db_bind_u64(stmt, 1, htlc_id);
+	db_bind_int(stmt, 2, wallet_forward_status_in_db(state));
+	db_exec_prepared_v2(stmt);
+	changed = db_count_changes(stmt) != 0;
+	tal_free(stmt);
+
+	return changed;
+}
+
 struct wallet_transaction *wallet_transactions_get(struct wallet *w, const tal_t *ctx)
 {
 	struct db_stmt *stmt;

wallet/wallet.h

@@ -1379,6 +1379,15 @@ const struct forwarding *wallet_forwarded_payments_get(struct wallet *w,
 						       const struct short_channel_id *chan_in,
 						       const struct short_channel_id *chan_out);
 
+/**
+ * Delete a particular forward entry
+ * Returns false if not found
+ */
+bool wallet_forward_delete(struct wallet *w,
+			   const struct short_channel_id *chan_in,
+			   u64 htlc_id,
+			   enum forward_status state);
+
 /**
  * Load remote_ann_node_sig and remote_ann_bitcoin_sig
  *