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…haining In chained proxy scenarios where shadowsocks_2022 is preceded by another proxy (or another shadowsocks_2022 instance), parentDialer.DialContext returns a netproxy.Conn (such as FakeNetPacketConn or other protocol UDP wrappers) that does not implement standard library net.Conn. Previously, ListenPacket performed an unchecked type assertion conn.(net.Conn), causing a runtime panic: interface conversion: *FakeNetPacketConn is not net.Conn: missing method LocalAddr Changes: - UdpConn: embed netproxy.Conn instead of net.Conn (UdpConn only invokes Read/Write/Close and deadline controls from the underlay). - NewUdpConn / NewUdpConnWithContext: accept netproxy.Conn directly. - ListenPacket: pass the netproxy.Conn returned by parentDialer without an unsafe type assertion to net.Conn. - UdpConn & FakeNetPacketConn: add LocalAddr() and RemoteAddr() forwarding methods so they continue to satisfy net.Conn for any external consumer that asserts it. - dialer_test: add regression tests for chained UDP underlays backed by bare netproxy.Conn and chained shadowsocks_2022 dialers.
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Problem
When
shadowsocks_2022is used as a downstream hop in a proxy chain (encountered in practice when runningdaewith chained-proxy nodes containing SS2022), UDP dialing triggers a runtime panic:In
ListenPacket,parentDialer.DialContext(...)returns anetproxy.Conn. For chained transports, the underlying connection satisfiesnetproxy.Connbut does not necessarily implement standard librarynet.Conn(LocalAddr/RemoteAddr). The unchecked type assertionconn.(net.Conn)panics.Solution
netproxy.Connfor UDP underlays:UdpConnonly requiresRead,Write,Close, and deadline controls from the underlying transport—it does not rely onLocalAddrorRemoteAddr. ChangedUdpConnto embednetproxy.Connand updated constructors accordingly.ListenPacket: Passed thenetproxy.Conndirectly without the unsafenet.Connassertion.LocalAddr()andRemoteAddr()to bothUdpConnandFakeNetPacketConnto forward inner transport addresses (or resolve the target address onFakeNetPacketConn), ensuring they satisfynet.Connfor any external callers asserting it.netproxy.Connunderlays and nestedshadowsocks_2022instances.