core: Function to discovery server by IP address Roon Server or my server machine reject replying to UDP multicast/broadcast after several attempts. This functionality can be a good way to avoid UDP multicast and broadcast issues.

Changes

3 changed files (+103/-0)

• core/src/discovery.zig
  • @@ -16,10 +16,13 @@ // SPDX-License-Identifier: Apache-2.0
    const std = @import("std"); + const moo = @import("moo"); const sood = @import("sood"); + const websocket = @import("websocket"); const Arc = @import("./Arc.zig"); const freelog = @import("./log.zig").freelog; + const RegistryService = @import("./services/registry.zig").RegistryService; const udp_dst = std.net.Address.initIp4( sood.discovery.multicast_ipv4_address,
  • @@ -271,6 +274,27 @@
    return result.retain(); } + pub fn resolve(server_id: [*:0]const u8, ip_addr: [*:0]const u8, http_port: u16) callconv(.C) ?*ScanResult { + var arena = std.heap.ArenaAllocator.init(std.heap.c_allocator); + defer arena.deinit(); + + const result = ScanResult.make() catch { + return null; + }; + + const id = std.mem.span(server_id); + const addr = std.mem.span(ip_addr); + + resolveInternal(arena.allocator(), id, addr, http_port, result) catch |err| { + result.code = switch (err) { + error.OutOfMemory => .out_of_memory, + else => .unknown, + }; + }; + + return result.retain(); + } + const ScanError = error{ NetworkUnavailable, SocketPermissionDenied,
  • @@ -403,6 +427,76 @@ result.code = .ok;
    return; } + fn resolveInternal( + allocator: std.mem.Allocator, + server_id: []const u8, + ip_addr: []const u8, + http_port: u16, + result: *ScanResult, + ) !void { + std.log.debug("Establishing WebSocket connection to {s}:{d}...", .{ + ip_addr, http_port, + }); + + var ws = try websocket.Client.init(allocator, .{ + .host = ip_addr, + .port = http_port, + .max_size = std.math.maxInt(u32), + }); + defer ws.deinit(); + + std.log.debug("Performing WebSocket handshake...", .{}); + ws.handshake("/api", .{ .timeout_ms = 1_000 }) catch |err| { + std.log.warn("Failed to perform WebSocket handshake, fallback to scan: {s}", .{@errorName(err)}); + result.code = .ok; + return; + }; + + std.log.debug("Requesting server info...", .{}); + + { + const req = try RegistryService.Info.request(allocator, 0); + defer allocator.free(req); + try ws.writeBin(req); + } + + const msg = (try ws.read()) orelse { + return error.ConnectionClosed; + }; + defer ws.done(msg); + + _, const header_ctx = try moo.Metadata.parse(msg.data); + const resp = try RegistryService.Info.response(allocator, header_ctx, msg.data); + defer resp.deinit(); + + if (!std.mem.eql(u8, server_id, resp.value.core_id)) { + std.log.info( + "Found Roon Server on saved IP address, got different server instance, fallback to scan: saved ID={s}, found ID={s}", + .{ + server_id, + resp.value.core_id, + }, + ); + result.code = .ok; + return; + } + + const addr = try std.net.Address.parseIp4(ip_addr, http_port); + + const sood_resp = sood.discovery.Response{ + .display_version = resp.value.display_version, + .name = resp.value.display_name, + .unique_id = server_id, + .http_port = http_port, + }; + + var server = try Server.make(&sood_resp, &addr); + errdefer server.release(); + + try result.initFindResult(server); + return; + } + fn createSocket() !std.posix.socket_t { std.log.debug("Opening UDP socket...", .{}); const sockfd = std.posix.socket(std.posix.AF.INET, std.posix.SOCK.DGRAM, 0) catch |err| {
  • @@ -539,4 +633,5 @@ ScanResult.export_capi();
    @export(&scan, .{ .name = "plac_discovery_scan" }); @export(&find, .{ .name = "plac_discovery_find" }); + @export(&resolve, .{ .name = "plac_discovery_resolve" }); }
• core/src/plac.h
  • @@ -63,6 +63,11 @@
    // discovery plac_discovery_scan_result *plac_discovery_scan(); plac_discovery_scan_result *plac_discovery_find(const char *server_id); + plac_discovery_scan_result *plac_discovery_resolve( + const char *server_id, + const char *ip_addr, + uint16_t http_port + ); // transport.NowPlaying typedef struct {
• core/src/plac.vapi
  • @@ -77,6 +77,9 @@ public ScanResult? scan();
    [CCode (cname = "plac_discovery_find")] public ScanResult? find(string server_id); + + [CCode (cname = "plac_discovery_resolve")] + public ScanResult? resolve(string server_id, string ip_addr, uint16 http_port); } namespace Transport {