[WIP] Added IPv6 support in the SRT protocol.

SRTHaishinKit/Sources/SRT/SRTSocket.swift

@@ -8,6 +8,7 @@ final actor SRTSocket {
 
     enum Error: Swift.Error {
         case notConnected
+        case invalidArgument(_ message: String)
         case rejected(_ reason: SRTRejectReason)
         case illegalState(_ message: String)
     }
@@ -128,28 +129,42 @@ final actor SRTSocket {
         let status: Int32 = try {
             switch url.mode {
             case .caller:
-                guard var remote = url.remote else {
-                    return SRT_ERROR
+                guard let remote = url.remote else {
+                    throw Error.invalidArgument("missing remote url")
+                }
+                return try remote.resolve(AI_ADDRCONFIG) { name, length in
+                    srt_connect(socket, name, length)
                 }
-                var remoteaddr = remote.makeSockaddr()
-                return srt_connect(socket, &remoteaddr, Int32(remote.size))
             case .listener:
-                guard var local = url.local else {
-                    return SRT_ERROR
+                guard let local = url.local else {
+                    throw Error.invalidArgument("missing local url")
                 }
-                var localaddr = local.makeSockaddr()
-                let status = srt_bind(socket, &localaddr, Int32(local.size))
-                guard status != SRT_ERROR else {
-                    throw makeSocketError()
+                let _: Int32 = try local.resolve(AI_PASSIVE) { name, length in
+                    let status = srt_bind(socket, name, length)
+                    if status == SRT_ERROR {
+                        return nil
+                    } else {
+                        return status
+                    }
                 }
                 return srt_listen(socket, 1)
             case .rendezvous:
-                guard var remote = url.remote, var local = url.local else {
-                    return SRT_ERROR
+                guard let remote = url.remote else {
+                    throw Error.invalidArgument("missing remote url")
+                }
+                guard let local = url.local else {
+                    throw Error.invalidArgument("missing local url")
+                }
+                return try remote.resolve(AI_PASSIVE | AI_ADDRCONFIG) { remotename, remotelen in
+                    return try local.resolve(AI_PASSIVE | AI_ADDRCONFIG) { localname, locallen in
+                        let status = srt_rendezvous(socket, localname, locallen, remotename, remotelen)
+                        if status == SRT_ERROR {
+                            return nil
+                        } else {
+                            return status
+                        }
+                    }
                 }
-                var remoteaddr = remote.makeSockaddr()
-                var localaddr = local.makeSockaddr()
-                return srt_rendezvous(socket, &remoteaddr, Int32(remote.size), &localaddr, Int32(local.size))
             }
         }()
         guard status != SRT_ERROR else {

SRTHaishinKit/Sources/SRT/SRTSocketURL.swift

@@ -27,20 +27,20 @@ struct SRTSocketURL {
     let mode: SRTMode
     let options: [SRTSocketOption]
 
-    var remote: sockaddr_in? {
+    var remote: AddrInfo? {
         guard let host = url.host else {
             return nil
         }
-        return .init(host, port: url.port ?? Self.defaultPort)
+        return AddrInfo(host: host, port: url.port ?? Self.defaultPort)
     }
 
-    var local: sockaddr_in? {
+    var local: AddrInfo? {
         let queryItems = Self.getQueryItems(url)
         let adapter = queryItems["adapter"] ?? "0.0.0.0"
         if let port = queryItems["port"] {
-            return .init(adapter, port: Int(port) ?? url.port ?? Self.defaultPort)
+            return AddrInfo(host: adapter, port: Int(port) ?? url.port ?? Self.defaultPort)
         }
-        return .init(adapter, port: url.port ?? Self.defaultPort)
+        return AddrInfo(host: adapter, port: url.port ?? Self.defaultPort)
     }
 
     init?(_ url: URL?) {

SRTHaishinKit/Sources/Util/AddrInfo.swift

@@ -0,0 +1,56 @@
+import Foundation
+import libsrt
+
+struct AddrInfo {
+    enum Error: Swift.Error {
+        case failedToGetaddrinfo(_ code: Int)
+        case failedToResolve
+    }
+
+    let host: String
+    let port: Int
+
+    @discardableResult
+    func resolve<R>(_ flags: Int32, lambda: (UnsafePointer<sockaddr>, Int32) throws -> R?) throws -> R {
+        var hints = addrinfo(
+            ai_flags: flags,
+            ai_family: AF_UNSPEC,
+            ai_socktype: SOCK_DGRAM,
+            ai_protocol: 0,
+            ai_addrlen: 0,
+            ai_canonname: nil,
+            ai_addr: nil,
+            ai_next: nil
+        )
+        var result: UnsafeMutablePointer<addrinfo>?
+        let rv = getaddrinfo(host, String(port), &hints, &result)
+        guard rv == 0 else {
+            throw Error.failedToGetaddrinfo(Int(rv))
+        }
+        defer {
+            freeaddrinfo(result)
+        }
+        var addr = sockaddr_storage()
+        var rp = result
+        while rp != nil {
+            if let ai = rp?.pointee {
+                memcpy(&addr, ai.ai_addr, Int(ai.ai_addrlen))
+                let result = withUnsafePointer(to: &addr) {
+                    $0.withMemoryRebound(to: sockaddr.self, capacity: 1) {
+                        do {
+                            return try lambda($0, Int32(ai.ai_addrlen))
+                        } catch {
+                            print("AddrInfo.resolve: lambda threw error for address \(host):\(port): \(error)")
+                            return nil
+                        }
+                    }
+                }
+                if let result {
+                    return result
+                }
+            }
+            rp = rp?.pointee.ai_next
+        }
+        throw Error.failedToResolve
+    }
+}