OXIESEC PANEL

Name	Size	Modified	Perms
📁 ..	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 addrselect.go	9.69 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 addrselect_test.go	8.5 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_aix.go	582 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_android.go	272 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_bsd.go	343 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_darwin.go	298 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_linux.go	642 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_netbsd.go	276 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_openbsd.go	276 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_resnew.go	580 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_resold.go	579 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_socknew.go	753 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_sockold.go	842 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_solaris.go	343 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_stub.go	1.33 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix.go	11.35 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_cgo.go	2.24 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_cgo_darwin.go	461 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_cgo_res.go	911 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_cgo_resn.go	998 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_syscall.go	2.99 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_test.go	1.44 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 conf.go	15.63 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 conf_test.go	12.28 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 conn_test.go	1.82 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dial.go	25.68 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dial_test.go	30.14 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dial_unix_test.go	2.77 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsclient.go	5.65 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsclient_test.go	1.51 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsclient_unix.go	24.26 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsclient_unix_test.go	69.13 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsconfig.go	1.73 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsconfig_unix.go	4.16 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsconfig_unix_test.go	7.07 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsconfig_windows.go	1.6 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsname_test.go	1.96 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_plan9.go	224 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_plan9_test.go	437 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_posix.go	543 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_posix_test.go	981 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_test.go	20.32 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_unix.go	382 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_unix_test.go	723 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_windows.go	355 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_windows_test.go	757 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 example_test.go	8.45 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 external_test.go	4.05 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_fake.go	3.79 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_js.go	627 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_plan9.go	3.56 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_posix.go	4.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_unix.go	5.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_wasip1.go	496 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_windows.go	6.14 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file.go	1.69 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_plan9.go	2.72 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_stub.go	481 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_test.go	6.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_unix.go	2.5 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_unix_test.go	2.07 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_wasip1.go	2.2 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_wasip1_test.go	3.76 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_windows.go	521 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hook.go	894 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hook_plan9.go	211 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hook_unix.go	658 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hook_windows.go	720 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hosts.go	3.48 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 hosts_test.go	5.6 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 http	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 interface.go	7.26 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_aix.go	4.46 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_bsd.go	2.82 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_bsd_test.go	1.44 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_bsdvar.go	718 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_darwin.go	1.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_freebsd.go	1.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_linux.go	6.96 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_linux_test.go	3.65 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_plan9.go	4.71 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_solaris.go	2.13 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_stub.go	814 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_test.go	9.76 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_unix_test.go	4.85 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_windows.go	5.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 internal	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 ip.go	13.88 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ip_test.go	25.6 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 iprawsock.go	7.11 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 iprawsock_plan9.go	874 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 iprawsock_posix.go	3.89 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 iprawsock_test.go	5.98 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock.go	9.05 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock_plan9.go	7.48 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock_plan9_test.go	645 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock_posix.go	7.86 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock_test.go	6.81 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 listen_test.go	20.5 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup.go	29.04 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_plan9.go	9.94 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_test.go	40.62 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_unix.go	3.35 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_windows.go	13.8 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_windows_test.go	8.93 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mac.go	1.88 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mac_test.go	3.26 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 mail	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 main_cloexec_test.go	693 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_conf_test.go	1.39 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_noconf_test.go	467 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_plan9_test.go	392 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_posix_test.go	1.37 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_test.go	7.53 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_unix_test.go	1.19 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_wasm_test.go	284 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_windows_test.go	1 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mockserver_test.go	10.77 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mptcpsock_linux.go	3.96 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mptcpsock_linux_test.go	4.06 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mptcpsock_stub.go	542 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 net.go	24.56 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 net_fake.go	26.36 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 net_fake_test.go	2.79 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 net_test.go	14 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 net_windows_test.go	16.28 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 netcgo_off.go	222 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 netcgo_on.go	220 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 netgo_netcgo.go	453 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 netgo_off.go	220 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 netgo_on.go	218 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📁 netip	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 nss.go	5.48 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 nss_test.go	3.4 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 packetconn_test.go	3.02 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 parse.go	6.04 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 parse_test.go	1.55 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 pipe.go	5.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 pipe_test.go	1.2 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 platform_test.go	4.33 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 port.go	1.46 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 port_test.go	1.34 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 port_unix.go	1.24 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 protoconn_test.go	7.44 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn.go	2.7 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn_stub_test.go	631 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn_test.go	4.33 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn_unix_test.go	2.96 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn_windows_test.go	3.12 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 resolverdialfunc_test.go	8.25 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rlimit_js.go	346 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 rlimit_unix.go	1.1 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 rpc	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 sendfile_linux.go	1.12 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_linux_test.go	1.93 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_stub.go	344 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_test.go	8.25 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_unix_alt.go	2.04 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_windows.go	1.02 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 server_test.go	11.67 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 smtp	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 sock_bsd.go	918 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_cloexec.go	1.38 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_linux.go	993 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_linux_test.go	575 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_plan9.go	262 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_posix.go	6.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_stub.go	390 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_windows.go	802 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockaddr_posix.go	1.45 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_aix.go	1.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_bsd.go	2.21 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_fake.go	955 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_linux.go	1.25 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_plan9.go	406 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_posix.go	2.13 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_solaris.go	1.25 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_windows.go	1.51 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_bsdvar.go	867 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_linux.go	735 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_posix.go	1.38 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_stub.go	769 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_windows.go	786 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 splice_linux.go	1.69 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 splice_stub.go	376 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 splice_test.go	13.48 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sys_cloexec.go	962 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock.go	11.75 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock_plan9.go	2.18 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock_posix.go	6.16 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock_test.go	17.68 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock_unix_test.go	2.34 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_darwin.go	770 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_dragonfly.go	698 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_openbsd.go	365 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_plan9.go	525 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_posix.go	442 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_solaris.go	1.15 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_stub.go	399 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_unix.go	722 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_windows.go	741 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📁 testdata	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📁 textproto	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 timeout_test.go	29.11 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock.go	11.83 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock_plan9.go	4.64 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock_plan9_test.go	1.31 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock_posix.go	7.53 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock_test.go	17.24 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock.go	10.12 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_linux_test.go	2.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_plan9.go	1.24 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_posix.go	6.64 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_readmsg_cloexec.go	654 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_readmsg_cmsg_cloexec.go	332 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_readmsg_other.go	275 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_readmsg_test.go	2.51 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_test.go	10.64 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_windows_test.go	2.03 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 url	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 write_unix_test.go	1.61 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 writev_test.go	5.03 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 writev_unix.go	666 bytes	02/02/2024 06:09:55 PM	rw-r--r--

Editing: addrselect.go

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Minimal RFC 6724 address selection.

package net

import (
	"net/netip"
	"sort"
)

func sortByRFC6724(addrs []IPAddr) {
	if len(addrs) < 2 {
		return
	}
	sortByRFC6724withSrcs(addrs, srcAddrs(addrs))
}

func sortByRFC6724withSrcs(addrs []IPAddr, srcs []netip.Addr) {
	if len(addrs) != len(srcs) {
		panic("internal error")
	}
	addrAttr := make([]ipAttr, len(addrs))
	srcAttr := make([]ipAttr, len(srcs))
	for i, v := range addrs {
		addrAttrIP, _ := netip.AddrFromSlice(v.IP)
		addrAttr[i] = ipAttrOf(addrAttrIP)
		srcAttr[i] = ipAttrOf(srcs[i])
	}
	sort.Stable(&byRFC6724{
		addrs:    addrs,
		addrAttr: addrAttr,
		srcs:     srcs,
		srcAttr:  srcAttr,
	})
}

// srcAddrs tries to UDP-connect to each address to see if it has a
// route. (This doesn't send any packets). The destination port
// number is irrelevant.
func srcAddrs(addrs []IPAddr) []netip.Addr {
	srcs := make([]netip.Addr, len(addrs))
	dst := UDPAddr{Port: 9}
	for i := range addrs {
		dst.IP = addrs[i].IP
		dst.Zone = addrs[i].Zone
		c, err := DialUDP("udp", nil, &dst)
		if err == nil {
			if src, ok := c.LocalAddr().(*UDPAddr); ok {
				srcs[i], _ = netip.AddrFromSlice(src.IP)
			}
			c.Close()
		}
	}
	return srcs
}

type ipAttr struct {
	Scope      scope
	Precedence uint8
	Label      uint8
}

func ipAttrOf(ip netip.Addr) ipAttr {
	if !ip.IsValid() {
		return ipAttr{}
	}
	match := rfc6724policyTable.Classify(ip)
	return ipAttr{
		Scope:      classifyScope(ip),
		Precedence: match.Precedence,
		Label:      match.Label,
	}
}

type byRFC6724 struct {
	addrs    []IPAddr // addrs to sort
	addrAttr []ipAttr
	srcs     []netip.Addr // or not valid addr if unreachable
	srcAttr  []ipAttr
}

func (s *byRFC6724) Len() int { return len(s.addrs) }

func (s *byRFC6724) Swap(i, j int) {
	s.addrs[i], s.addrs[j] = s.addrs[j], s.addrs[i]
	s.srcs[i], s.srcs[j] = s.srcs[j], s.srcs[i]
	s.addrAttr[i], s.addrAttr[j] = s.addrAttr[j], s.addrAttr[i]
	s.srcAttr[i], s.srcAttr[j] = s.srcAttr[j], s.srcAttr[i]
}

// Less reports whether i is a better destination address for this
// host than j.
//
// The algorithm and variable names comes from RFC 6724 section 6.
func (s *byRFC6724) Less(i, j int) bool {
	DA := s.addrs[i].IP
	DB := s.addrs[j].IP
	SourceDA := s.srcs[i]
	SourceDB := s.srcs[j]
	attrDA := &s.addrAttr[i]
	attrDB := &s.addrAttr[j]
	attrSourceDA := &s.srcAttr[i]
	attrSourceDB := &s.srcAttr[j]

const preferDA = true
	const preferDB = false

// Rule 1: Avoid unusable destinations.
	// If DB is known to be unreachable or if Source(DB) is undefined, then
	// prefer DA.  Similarly, if DA is known to be unreachable or if
	// Source(DA) is undefined, then prefer DB.
	if !SourceDA.IsValid() && !SourceDB.IsValid() {
		return false // "equal"
	}
	if !SourceDB.IsValid() {
		return preferDA
	}
	if !SourceDA.IsValid() {
		return preferDB
	}

// Rule 2: Prefer matching scope.
	// If Scope(DA) = Scope(Source(DA)) and Scope(DB) <> Scope(Source(DB)),
	// then prefer DA.  Similarly, if Scope(DA) <> Scope(Source(DA)) and
	// Scope(DB) = Scope(Source(DB)), then prefer DB.
	if attrDA.Scope == attrSourceDA.Scope && attrDB.Scope != attrSourceDB.Scope {
		return preferDA
	}
	if attrDA.Scope != attrSourceDA.Scope && attrDB.Scope == attrSourceDB.Scope {
		return preferDB
	}

// Rule 3: Avoid deprecated addresses.
	// If Source(DA) is deprecated and Source(DB) is not, then prefer DB.
	// Similarly, if Source(DA) is not deprecated and Source(DB) is
	// deprecated, then prefer DA.

// TODO(bradfitz): implement? low priority for now.

// Rule 4: Prefer home addresses.
	// If Source(DA) is simultaneously a home address and care-of address
	// and Source(DB) is not, then prefer DA.  Similarly, if Source(DB) is
	// simultaneously a home address and care-of address and Source(DA) is
	// not, then prefer DB.

// TODO(bradfitz): implement? low priority for now.

// Rule 5: Prefer matching label.
	// If Label(Source(DA)) = Label(DA) and Label(Source(DB)) <> Label(DB),
	// then prefer DA.  Similarly, if Label(Source(DA)) <> Label(DA) and
	// Label(Source(DB)) = Label(DB), then prefer DB.
	if attrSourceDA.Label == attrDA.Label &&
		attrSourceDB.Label != attrDB.Label {
		return preferDA
	}
	if attrSourceDA.Label != attrDA.Label &&
		attrSourceDB.Label == attrDB.Label {
		return preferDB
	}

// Rule 6: Prefer higher precedence.
	// If Precedence(DA) > Precedence(DB), then prefer DA.  Similarly, if
	// Precedence(DA) < Precedence(DB), then prefer DB.
	if attrDA.Precedence > attrDB.Precedence {
		return preferDA
	}
	if attrDA.Precedence < attrDB.Precedence {
		return preferDB
	}

// Rule 7: Prefer native transport.
	// If DA is reached via an encapsulating transition mechanism (e.g.,
	// IPv6 in IPv4) and DB is not, then prefer DB.  Similarly, if DB is
	// reached via encapsulation and DA is not, then prefer DA.

// TODO(bradfitz): implement? low priority for now.

// Rule 8: Prefer smaller scope.
	// If Scope(DA) < Scope(DB), then prefer DA.  Similarly, if Scope(DA) >
	// Scope(DB), then prefer DB.
	if attrDA.Scope < attrDB.Scope {
		return preferDA
	}
	if attrDA.Scope > attrDB.Scope {
		return preferDB
	}

// Rule 9: Use the longest matching prefix.
	// When DA and DB belong to the same address family (both are IPv6 or
	// both are IPv4 [but see below]): If CommonPrefixLen(Source(DA), DA) >
	// CommonPrefixLen(Source(DB), DB), then prefer DA.  Similarly, if
	// CommonPrefixLen(Source(DA), DA) < CommonPrefixLen(Source(DB), DB),
	// then prefer DB.
	//
	// However, applying this rule to IPv4 addresses causes
	// problems (see issues 13283 and 18518), so limit to IPv6.
	if DA.To4() == nil && DB.To4() == nil {
		commonA := commonPrefixLen(SourceDA, DA)
		commonB := commonPrefixLen(SourceDB, DB)

if commonA > commonB {
			return preferDA
		}
		if commonA < commonB {
			return preferDB
		}
	}

// Rule 10: Otherwise, leave the order unchanged.
	// If DA preceded DB in the original list, prefer DA.
	// Otherwise, prefer DB.
	return false // "equal"
}

type policyTableEntry struct {
	Prefix     netip.Prefix
	Precedence uint8
	Label      uint8
}

type policyTable []policyTableEntry

// RFC 6724 section 2.1.
// Items are sorted by the size of their Prefix.Mask.Size,
var rfc6724policyTable = policyTable{
	{
		// "::1/128"
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01}), 128),
		Precedence: 50,
		Label:      0,
	},
	{
		// "::ffff:0:0/96"
		// IPv4-compatible, etc.
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff}), 96),
		Precedence: 35,
		Label:      4,
	},
	{
		// "::/96"
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{}), 96),
		Precedence: 1,
		Label:      3,
	},
	{
		// "2001::/32"
		// Teredo
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{0x20, 0x01}), 32),
		Precedence: 5,
		Label:      5,
	},
	{
		// "2002::/16"
		// 6to4
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{0x20, 0x02}), 16),
		Precedence: 30,
		Label:      2,
	},
	{
		// "3ffe::/16"
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{0x3f, 0xfe}), 16),
		Precedence: 1,
		Label:      12,
	},
	{
		// "fec0::/10"
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{0xfe, 0xc0}), 10),
		Precedence: 1,
		Label:      11,
	},
	{
		// "fc00::/7"
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{0xfc}), 7),
		Precedence: 3,
		Label:      13,
	},
	{
		// "::/0"
		Prefix:     netip.PrefixFrom(netip.AddrFrom16([16]byte{}), 0),
		Precedence: 40,
		Label:      1,
	},
}

// Classify returns the policyTableEntry of the entry with the longest
// matching prefix that contains ip.
// The table t must be sorted from largest mask size to smallest.
func (t policyTable) Classify(ip netip.Addr) policyTableEntry {
	// Prefix.Contains() will not match an IPv6 prefix for an IPv4 address.
	if ip.Is4() {
		ip = netip.AddrFrom16(ip.As16())
	}
	for _, ent := range t {
		if ent.Prefix.Contains(ip) {
			return ent
		}
	}
	return policyTableEntry{}
}

// RFC 6724 section 3.1.
type scope uint8

const (
	scopeInterfaceLocal scope = 0x1
	scopeLinkLocal      scope = 0x2
	scopeAdminLocal     scope = 0x4
	scopeSiteLocal      scope = 0x5
	scopeOrgLocal       scope = 0x8
	scopeGlobal         scope = 0xe
)

func classifyScope(ip netip.Addr) scope {
	if ip.IsLoopback() || ip.IsLinkLocalUnicast() {
		return scopeLinkLocal
	}
	ipv6 := ip.Is6() && !ip.Is4In6()
	ipv6AsBytes := ip.As16()
	if ipv6 && ip.IsMulticast() {
		return scope(ipv6AsBytes[1] & 0xf)
	}
	// Site-local addresses are defined in RFC 3513 section 2.5.6
	// (and deprecated in RFC 3879).
	if ipv6 && ipv6AsBytes[0] == 0xfe && ipv6AsBytes[1]&0xc0 == 0xc0 {
		return scopeSiteLocal
	}
	return scopeGlobal
}

// commonPrefixLen reports the length of the longest prefix (looking
// at the most significant, or leftmost, bits) that the
// two addresses have in common, up to the length of a's prefix (i.e.,
// the portion of the address not including the interface ID).
//
// If a or b is an IPv4 address as an IPv6 address, the IPv4 addresses
// are compared (with max common prefix length of 32).
// If a and b are different IP versions, 0 is returned.
//
// See https://tools.ietf.org/html/rfc6724#section-2.2
func commonPrefixLen(a netip.Addr, b IP) (cpl int) {
	if b4 := b.To4(); b4 != nil {
		b = b4
	}
	aAsSlice := a.AsSlice()
	if len(aAsSlice) != len(b) {
		return 0
	}
	// If IPv6, only up to the prefix (first 64 bits)
	if len(aAsSlice) > 8 {
		aAsSlice = aAsSlice[:8]
		b = b[:8]
	}
	for len(aAsSlice) > 0 {
		if aAsSlice[0] == b[0] {
			cpl += 8
			aAsSlice = aAsSlice[1:]
			b = b[1:]
			continue
		}
		bits := 8
		ab, bb := aAsSlice[0], b[0]
		for {
			ab >>= 1
			bb >>= 1
			bits--
			if ab == bb {
				cpl += bits
				return
			}
		}
	}
	return
}