introduce support for alternative addresses for peer connections

doc/schemas/lightning-alt-addr.json

@@ -0,0 +1,92 @@
+{
+  "$schema": "../rpc-schema-draft.json",
+  "type": "object",
+  "additionalProperties": false,
+  "rpc": "alt-addr",
+  "title": "Command to set or clear alternative addresses for node connection.",
+  "description": [
+    "The **alt-addr** RPC command allows a node to set or clear alternate addresses for incoming connections.",
+    "These addresses can be used by peers to connect to the node, offering flexibility in network configurations."
+  ],
+  "request": {
+    "required": [
+      "node_id",
+      "alt_addrs"
+    ],
+    "properties": {
+      "node_id": {
+        "type": "pubkey",
+        "description": [
+          "The public key of the node for which the alternate addresses are being set."
+        ]
+      },
+      "alt_addrs": {
+        "type": "array",
+        "items": {
+          "type": "string",
+          "description": [
+            "A list of alternate addresses in the format 'ip:port'.",
+            "An empty string can be used to clear existing alternate addresses."
+          ]
+        }
+      }
+    }
+  },
+  "response": {
+    "required": [],
+    "properties": {}
+  },
+  "errors": [
+    "On failure, one of the following error codes may be returned:",
+    "",
+    "- -32602: Error in given parameters (e.g., invalid address format or node ID)."
+  ],
+  "author": [
+    "Max Ranti <<[email protected]>> wrote the initial version of this man page."
+  ],
+  "resources": [
+    "Main web site: <https://github.com/ElementsProject/lightning>"
+  ],
+  "examples": [
+    {
+      "request": {
+        "id": "example:alt-addr#1",
+        "method": "alt-addr",
+        "params": {
+          "node_id": "0290bb147b0ea569938db873d5899048bd211ad034e57b47824b348756f66e8bca",
+          "alt_addrs": [
+            "127.0.0.21:9735"
+          ]
+        }
+      },
+      "response": {}
+    },
+    {
+      "request": {
+        "id": "example:alt-addr#2",
+        "method": "alt-addr",
+        "params": {
+          "node_id": "0290bb147b0ea569938db873d5899048bd211ad034e57b47824b348756f66e8bca",
+          "alt_addrs": [
+            "127.0.0.21:9735",
+            "192.168.1.1:9736"
+          ]
+        }
+      },
+      "response": {}
+    },
+    {
+      "request": {
+        "id": "example:alt-addr#3",
+        "method": "alt-addr",
+        "params": {
+          "node_id": "0290bb147b0ea569938db873d5899048bd211ad034e57b47824b348756f66e8bca",
+          "alt_addrs": [
+            ""
+          ]
+        }
+      },
+      "response": {}
+    }
+  ]
+}

lightningd/channel_control.c

@@ -2462,3 +2462,63 @@ static const struct json_command dev_quiesce_command = {
 	.dev_only = true,
 };
 AUTODATA(json_command, &dev_quiesce_command);
+
+static struct command_result *json_alt_addr(struct command *cmd,
+					    const char *buffer,
+					    const jsmntok_t *obj UNNEEDED,
+					    const jsmntok_t *params)
+{
+	struct node_id *p_id;
+	struct peer *peer;
+	struct channel *channel;
+	const jsmntok_t *alt_addrs_tok;
+	bool more_than_one;
+
+	if (!param_check(cmd, buffer, params,
+			 p_req("node_id", param_node_id, &p_id),
+			 p_req("alt_addrs", param_array, &alt_addrs_tok),
+			 NULL))
+		return command_param_failed();
+
+	peer = peer_by_id(cmd->ld, p_id);
+	if (!peer) {
+		return command_fail(cmd, JSONRPC2_INVALID_REQUEST,
+				    "No such peer: %s",
+				    fmt_node_id(cmd, p_id));
+	}
+
+	channel = peer_any_channel(peer, channel_state_can_add_htlc, &more_than_one);
+	if (!channel || !channel->owner)
+		return command_fail(cmd, LIGHTNINGD, "Peer bad state");
+	/* This is a dev command: fix the api if you need this! */
+	if (more_than_one)
+		return command_fail(cmd, LIGHTNINGD, "More than one channel");
+
+	if (command_check_only(cmd))
+		return command_check_done(cmd);
+
+	char *addr_list = tal_fmt(tmpctx, "%s", json_strdup(tmpctx, buffer, json_get_arr(alt_addrs_tok, 0)));
+
+	for (size_t i = 1; i < alt_addrs_tok->size; i++) {
+		const jsmntok_t *addr_tok = json_get_arr(alt_addrs_tok, i);
+		const char *my_alt_addr = json_strdup(tmpctx, buffer, addr_tok);
+
+		/* Format the rpc array into comma-seperated string for the db's */
+		addr_list = tal_fmt(tmpctx, "%s,%s", addr_list, my_alt_addr);
+	}
+
+	u8 *msg = towire_channeld_peer_alt_addr(peer, (u8 *)addr_list);
+	subd_send_msg(channel->owner, take(msg));
+
+	wallet_add_alt_addr(cmd->ld->wallet->db, p_id, addr_list, true);
+	process_and_update_whitelist(cmd->ld, p_id, (u8 *)addr_list);
+
+	return command_success(cmd, json_stream_success(cmd));
+}
+
+static const struct json_command alt_addr_command = {
+	"alt-addr",
+	json_alt_addr,
+	.dev_only = true,
+};
+AUTODATA(json_command, &alt_addr_command);