From 2f63afdc7afbf0af957f4dd5f60279711602b53c Mon Sep 17 00:00:00 2001 From: Mikio Hara Date: Wed, 1 Feb 2012 01:53:26 +0900 Subject: [PATCH] net: ListenMulticastUDP to listen concurrently across multiple listeners This CL introduces new function ListenMulticastUDP to fix multicast UDP listening across multiple listeners issue, to replace old multicast methods JoinGroup and LeaveGroup on UDPConn. This CL also enables multicast testing by default. Fixes #2730. R=rsc, paul.a.lalonde, fullung, devon.odell CC=golang-dev https://golang.org/cl/5562048 --- doc/go1.html | 9 +++- doc/go1.tmpl | 9 +++- src/pkg/net/multicast_test.go | 76 ++++++++++----------------- src/pkg/net/sock.go | 11 +++- src/pkg/net/sock_bsd.go | 24 +++++++++ src/pkg/net/sock_linux.go | 24 +++++++++ src/pkg/net/sock_windows.go | 24 +++++++++ src/pkg/net/sockopt_bsd.go | 36 +++++++++---- src/pkg/net/sockopt_linux.go | 26 ++++++--- src/pkg/net/sockopt_windows.go | 20 ++++--- src/pkg/net/udpsock_plan9.go | 22 +++----- src/pkg/net/udpsock_posix.go | 96 +++++++++++++++++++++++++--------- 12 files changed, 259 insertions(+), 118 deletions(-) diff --git a/doc/go1.html b/doc/go1.html index 0f53efa9f5..4c118e0a9b 100644 --- a/doc/go1.html +++ b/doc/go1.html @@ -1215,8 +1215,13 @@ reads and writes will time out and no longer block.

-There is also a new net.DialTimeout method to simplify -timing out dialing a network address. +There are also new functions +net.DialTimeout +to simplify timing out dialing a network address and +net.ListenMulticastUDP +to allow multicast UDP to listen concurrently across multiple listeners. +The net.ListenMulticastUDP function replaces the old +JoinGroup and LeaveGroup methods.

diff --git a/doc/go1.tmpl b/doc/go1.tmpl index 0e5b1ed534..940f2d75c0 100644 --- a/doc/go1.tmpl +++ b/doc/go1.tmpl @@ -1118,8 +1118,13 @@ reads and writes will time out and no longer block.

-There is also a new net.DialTimeout method to simplify -timing out dialing a network address. +There are also new functions +net.DialTimeout +to simplify timing out dialing a network address and +net.ListenMulticastUDP +to allow multicast UDP to listen concurrently across multiple listeners. +The net.ListenMulticastUDP function replaces the old +JoinGroup and LeaveGroup methods.

diff --git a/src/pkg/net/multicast_test.go b/src/pkg/net/multicast_test.go index b6a2fa6c88..0daca19ce5 100644 --- a/src/pkg/net/multicast_test.go +++ b/src/pkg/net/multicast_test.go @@ -5,43 +5,36 @@ package net import ( - "flag" "os" "runtime" "testing" ) -var multicast = flag.Bool("multicast", false, "enable multicast tests") - -var multicastUDPTests = []struct { +var listenMulticastUDPTests = []struct { net string - laddr IP - gaddr IP + gaddr *UDPAddr flags Flags ipv6 bool }{ // cf. RFC 4727: Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP Headers - {"udp", IPv4zero, IPv4(224, 0, 0, 254), (FlagUp | FlagLoopback), false}, - {"udp4", IPv4zero, IPv4(224, 0, 0, 254), (FlagUp | FlagLoopback), false}, - {"udp", IPv6unspecified, ParseIP("ff0e::114"), (FlagUp | FlagLoopback), true}, - {"udp6", IPv6unspecified, ParseIP("ff01::114"), (FlagUp | FlagLoopback), true}, - {"udp6", IPv6unspecified, ParseIP("ff02::114"), (FlagUp | FlagLoopback), true}, - {"udp6", IPv6unspecified, ParseIP("ff04::114"), (FlagUp | FlagLoopback), true}, - {"udp6", IPv6unspecified, ParseIP("ff05::114"), (FlagUp | FlagLoopback), true}, - {"udp6", IPv6unspecified, ParseIP("ff08::114"), (FlagUp | FlagLoopback), true}, - {"udp6", IPv6unspecified, ParseIP("ff0e::114"), (FlagUp | FlagLoopback), true}, + {"udp", &UDPAddr{IPv4(224, 0, 0, 254), 12345}, FlagUp | FlagLoopback, false}, + {"udp4", &UDPAddr{IPv4(224, 0, 0, 254), 12345}, FlagUp | FlagLoopback, false}, + {"udp", &UDPAddr{ParseIP("ff0e::114"), 12345}, FlagUp | FlagLoopback, true}, + {"udp6", &UDPAddr{ParseIP("ff01::114"), 12345}, FlagUp | FlagLoopback, true}, + {"udp6", &UDPAddr{ParseIP("ff02::114"), 12345}, FlagUp | FlagLoopback, true}, + {"udp6", &UDPAddr{ParseIP("ff04::114"), 12345}, FlagUp | FlagLoopback, true}, + {"udp6", &UDPAddr{ParseIP("ff05::114"), 12345}, FlagUp | FlagLoopback, true}, + {"udp6", &UDPAddr{ParseIP("ff08::114"), 12345}, FlagUp | FlagLoopback, true}, + {"udp6", &UDPAddr{ParseIP("ff0e::114"), 12345}, FlagUp | FlagLoopback, true}, } -func TestMulticastUDP(t *testing.T) { - if runtime.GOOS == "plan9" || runtime.GOOS == "windows" { - return - } - if !*multicast { - t.Logf("test disabled; use --multicast to enable") +func TestListenMulticastUDP(t *testing.T) { + switch runtime.GOOS { + case "netbsd", "openbsd", "plan9", "windows": return } - for _, tt := range multicastUDPTests { + for _, tt := range listenMulticastUDPTests { if tt.ipv6 && (!supportsIPv6 || os.Getuid() != 0) { continue } @@ -60,14 +53,11 @@ func TestMulticastUDP(t *testing.T) { t.Logf("an appropriate multicast interface not found") return } - c, err := ListenUDP(tt.net, &UDPAddr{IP: tt.laddr}) + c, err := ListenMulticastUDP(tt.net, ifi, tt.gaddr) if err != nil { - t.Fatalf("ListenUDP failed: %v", err) - } - defer c.Close() - if err := c.JoinGroup(ifi, tt.gaddr); err != nil { - t.Fatalf("JoinGroup failed: %v", err) + t.Fatalf("ListenMulticastUDP failed: %v", err) } + defer c.Close() // test to listen concurrently across multiple listeners if !tt.ipv6 { testIPv4MulticastSocketOptions(t, c.fd, ifi) } else { @@ -79,7 +69,7 @@ func TestMulticastUDP(t *testing.T) { } var found bool for _, ifma := range ifmat { - if ifma.(*IPAddr).IP.Equal(tt.gaddr) { + if ifma.(*IPAddr).IP.Equal(tt.gaddr.IP) { found = true break } @@ -87,23 +77,16 @@ func TestMulticastUDP(t *testing.T) { if !found { t.Fatalf("%q not found in RIB", tt.gaddr.String()) } - if err := c.LeaveGroup(ifi, tt.gaddr); err != nil { - t.Fatalf("LeaveGroup failed: %v", err) - } } } -func TestSimpleMulticastUDP(t *testing.T) { - if runtime.GOOS == "plan9" { - return - } - if !*multicast { - t.Logf("test disabled; use --multicast to enable") +func TestSimpleListenMulticastUDP(t *testing.T) { + switch runtime.GOOS { + case "plan9": return } - for _, tt := range multicastUDPTests { - var ifi *Interface + for _, tt := range listenMulticastUDPTests { if tt.ipv6 { continue } @@ -112,6 +95,7 @@ func TestSimpleMulticastUDP(t *testing.T) { if err != nil { t.Fatalf("Interfaces failed: %v", err) } + var ifi *Interface for _, x := range ift { if x.Flags&tt.flags == tt.flags { ifi = &x @@ -122,17 +106,11 @@ func TestSimpleMulticastUDP(t *testing.T) { t.Logf("an appropriate multicast interface not found") return } - c, err := ListenUDP(tt.net, &UDPAddr{IP: tt.laddr}) + c, err := ListenMulticastUDP(tt.net, ifi, tt.gaddr) if err != nil { - t.Fatalf("ListenUDP failed: %v", err) - } - defer c.Close() - if err := c.JoinGroup(ifi, tt.gaddr); err != nil { - t.Fatalf("JoinGroup failed: %v", err) - } - if err := c.LeaveGroup(ifi, tt.gaddr); err != nil { - t.Fatalf("LeaveGroup failed: %v", err) + t.Fatalf("ListenMulticastUDP failed: %v", err) } + c.Close() } } diff --git a/src/pkg/net/sock.go b/src/pkg/net/sock.go index 867e328f12..2dbe1082e4 100644 --- a/src/pkg/net/sock.go +++ b/src/pkg/net/sock.go @@ -28,9 +28,18 @@ func socket(net string, f, t, p int, la, ra syscall.Sockaddr, toAddr func(syscal syscall.CloseOnExec(s) syscall.ForkLock.RUnlock() - setDefaultSockopts(s, f, t) + err = setDefaultSockopts(s, f, t) + if err != nil { + closesocket(s) + return nil, err + } if la != nil { + la, err = listenerSockaddr(s, f, la, toAddr) + if err != nil { + closesocket(s) + return nil, err + } err = syscall.Bind(s, la) if err != nil { closesocket(s) diff --git a/src/pkg/net/sock_bsd.go b/src/pkg/net/sock_bsd.go index 630a91ed9f..7c693a271f 100644 --- a/src/pkg/net/sock_bsd.go +++ b/src/pkg/net/sock_bsd.go @@ -31,3 +31,27 @@ func maxListenerBacklog() int { } return int(n) } + +func listenerSockaddr(s, f int, la syscall.Sockaddr, toAddr func(syscall.Sockaddr) Addr) (syscall.Sockaddr, error) { + a := toAddr(la) + if a == nil { + return la, nil + } + switch v := a.(type) { + case *UDPAddr: + if v.IP.IsMulticast() { + err := setDefaultMulticastSockopts(s) + if err != nil { + return nil, err + } + switch f { + case syscall.AF_INET: + v.IP = IPv4zero + case syscall.AF_INET6: + v.IP = IPv6unspecified + } + return v.sockaddr(f) + } + } + return la, nil +} diff --git a/src/pkg/net/sock_linux.go b/src/pkg/net/sock_linux.go index 2cbc34f24b..0743843bf2 100644 --- a/src/pkg/net/sock_linux.go +++ b/src/pkg/net/sock_linux.go @@ -25,3 +25,27 @@ func maxListenerBacklog() int { } return n } + +func listenerSockaddr(s, f int, la syscall.Sockaddr, toAddr func(syscall.Sockaddr) Addr) (syscall.Sockaddr, error) { + a := toAddr(la) + if a == nil { + return la, nil + } + switch v := a.(type) { + case *UDPAddr: + if v.IP.IsMulticast() { + err := setDefaultMulticastSockopts(s) + if err != nil { + return nil, err + } + switch f { + case syscall.AF_INET: + v.IP = IPv4zero + case syscall.AF_INET6: + v.IP = IPv6unspecified + } + return v.sockaddr(f) + } + } + return la, nil +} diff --git a/src/pkg/net/sock_windows.go b/src/pkg/net/sock_windows.go index 2d803de1fc..434122c9e4 100644 --- a/src/pkg/net/sock_windows.go +++ b/src/pkg/net/sock_windows.go @@ -12,3 +12,27 @@ func maxListenerBacklog() int { // TODO: Implement this return syscall.SOMAXCONN } + +func listenerSockaddr(s syscall.Handle, f int, la syscall.Sockaddr, toAddr func(syscall.Sockaddr) Addr) (syscall.Sockaddr, error) { + a := toAddr(la) + if a == nil { + return la, nil + } + switch v := a.(type) { + case *UDPAddr: + if v.IP.IsMulticast() { + err := setDefaultMulticastSockopts(s) + if err != nil { + return nil, err + } + switch f { + case syscall.AF_INET: + v.IP = IPv4zero + case syscall.AF_INET6: + v.IP = IPv6unspecified + } + return v.sockaddr(f) + } + } + return la, nil +} diff --git a/src/pkg/net/sockopt_bsd.go b/src/pkg/net/sockopt_bsd.go index 2093e08127..bc76465062 100644 --- a/src/pkg/net/sockopt_bsd.go +++ b/src/pkg/net/sockopt_bsd.go @@ -9,37 +9,55 @@ package net import ( + "os" "syscall" ) -func setDefaultSockopts(s, f, t int) { +func setDefaultSockopts(s, f, t int) error { switch f { case syscall.AF_INET6: // Allow both IP versions even if the OS default is otherwise. + // Note that some operating systems never admit this option. syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, 0) } if f == syscall.AF_UNIX || (f == syscall.AF_INET || f == syscall.AF_INET6) && t == syscall.SOCK_STREAM { // Allow reuse of recently-used addresses. - syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } // Allow reuse of recently-used ports. // This option is supported only in descendants of 4.4BSD, // to make an effective multicast application and an application // that requires quick draw possible. - syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1) + err = syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } } // Allow broadcast. - syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1) + err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } + + return nil } -func setDefaultMulticastSockopts(fd *netFD) { - fd.incref() - defer fd.decref() +func setDefaultMulticastSockopts(s int) error { // Allow multicast UDP and raw IP datagram sockets to listen // concurrently across multiple listeners. - syscall.SetsockoptInt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) - syscall.SetsockoptInt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1) + err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } + err = syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } + return nil } diff --git a/src/pkg/net/sockopt_linux.go b/src/pkg/net/sockopt_linux.go index 9dbb4e5dde..67c1dc87a7 100644 --- a/src/pkg/net/sockopt_linux.go +++ b/src/pkg/net/sockopt_linux.go @@ -7,31 +7,43 @@ package net import ( + "os" "syscall" ) -func setDefaultSockopts(s, f, t int) { +func setDefaultSockopts(s, f, t int) error { switch f { case syscall.AF_INET6: // Allow both IP versions even if the OS default is otherwise. + // Note that some operating systems never admit this option. syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, 0) } if f == syscall.AF_UNIX || (f == syscall.AF_INET || f == syscall.AF_INET6) && t == syscall.SOCK_STREAM { // Allow reuse of recently-used addresses. - syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } + } // Allow broadcast. - syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1) + err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } + return nil } -func setDefaultMulticastSockopts(fd *netFD) { - fd.incref() - defer fd.decref() +func setDefaultMulticastSockopts(s int) error { // Allow multicast UDP and raw IP datagram sockets to listen // concurrently across multiple listeners. - syscall.SetsockoptInt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } + return nil } diff --git a/src/pkg/net/sockopt_windows.go b/src/pkg/net/sockopt_windows.go index a7b5606d86..2b861de30b 100644 --- a/src/pkg/net/sockopt_windows.go +++ b/src/pkg/net/sockopt_windows.go @@ -7,13 +7,15 @@ package net import ( + "os" "syscall" ) -func setDefaultSockopts(s syscall.Handle, f, t int) { +func setDefaultSockopts(s syscall.Handle, f, t int) error { switch f { case syscall.AF_INET6: // Allow both IP versions even if the OS default is otherwise. + // Note that some operating systems never admit this option. syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, 0) } @@ -25,14 +27,20 @@ func setDefaultSockopts(s syscall.Handle, f, t int) { // to be handled by the correct socket. // Allow broadcast. - syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1) + err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } + return nil } -func setDefaultMulticastSockopts(fd *netFD) { - fd.incref() - defer fd.decref() +func setDefaultMulticastSockopts(s syscall.Handle) error { // Allow multicast UDP and raw IP datagram sockets to listen // concurrently across multiple listeners. - syscall.SetsockoptInt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) + if err != nil { + return os.NewSyscallError("setsockopt", err) + } + return nil } diff --git a/src/pkg/net/udpsock_plan9.go b/src/pkg/net/udpsock_plan9.go index cf50753688..f90a5fe9ab 100644 --- a/src/pkg/net/udpsock_plan9.go +++ b/src/pkg/net/udpsock_plan9.go @@ -186,20 +186,10 @@ func ListenUDP(net string, laddr *UDPAddr) (c *UDPConn, err error) { return &UDPConn{*l.plan9Conn()}, nil } -// JoinGroup joins the IP multicast group named by addr on ifi, -// which specifies the interface to join. JoinGroup uses the -// default multicast interface if ifi is nil. -func (c *UDPConn) JoinGroup(ifi *Interface, addr IP) error { - if !c.ok() { - return os.EINVAL - } - return os.EPLAN9 -} - -// LeaveGroup exits the IP multicast group named by addr on ifi. -func (c *UDPConn) LeaveGroup(ifi *Interface, addr IP) error { - if !c.ok() { - return os.EINVAL - } - return os.EPLAN9 +// ListenMulticastUDP listens for incoming multicast UDP packets +// addressed to the group address gaddr on ifi, which specifies +// the interface to join. ListenMulticastUDP uses default +// multicast interface if ifi is nil. +func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) { + return nil, os.EPLAN9 } diff --git a/src/pkg/net/udpsock_posix.go b/src/pkg/net/udpsock_posix.go index 0f63e95c1b..6108373568 100644 --- a/src/pkg/net/udpsock_posix.go +++ b/src/pkg/net/udpsock_posix.go @@ -61,7 +61,7 @@ func (c *UDPConn) ok() bool { return c != nil && c.fd != nil } // Implementation of the Conn interface - see Conn for documentation. // Read implements the Conn Read method. -func (c *UDPConn) Read(b []byte) (n int, err error) { +func (c *UDPConn) Read(b []byte) (int, error) { if !c.ok() { return 0, os.EINVAL } @@ -69,7 +69,7 @@ func (c *UDPConn) Read(b []byte) (n int, err error) { } // Write implements the Conn Write method. -func (c *UDPConn) Write(b []byte) (n int, err error) { +func (c *UDPConn) Write(b []byte) (int, error) { if !c.ok() { return 0, os.EINVAL } @@ -167,7 +167,7 @@ func (c *UDPConn) ReadFromUDP(b []byte) (n int, addr *UDPAddr, err error) { } // ReadFrom implements the PacketConn ReadFrom method. -func (c *UDPConn) ReadFrom(b []byte) (n int, addr Addr, err error) { +func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) { if !c.ok() { return 0, nil, os.EINVAL } @@ -207,6 +207,11 @@ func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) { return c.WriteToUDP(b, a) } +// File returns a copy of the underlying os.File, set to blocking mode. +// It is the caller's responsibility to close f when finished. +// Closing c does not affect f, and closing f does not affect c. +func (c *UDPConn) File() (f *os.File, err error) { return c.fd.dup() } + // DialUDP connects to the remote address raddr on the network net, // which must be "udp", "udp4", or "udp6". If laddr is not nil, it is used // as the local address for the connection. @@ -246,36 +251,75 @@ func ListenUDP(net string, laddr *UDPAddr) (*UDPConn, error) { return newUDPConn(fd), nil } -// File returns a copy of the underlying os.File, set to blocking mode. -// It is the caller's responsibility to close f when finished. -// Closing c does not affect f, and closing f does not affect c. -func (c *UDPConn) File() (f *os.File, err error) { return c.fd.dup() } +// ListenMulticastUDP listens for incoming multicast UDP packets +// addressed to the group address gaddr on ifi, which specifies +// the interface to join. ListenMulticastUDP uses default +// multicast interface if ifi is nil. +func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) { + switch net { + case "udp", "udp4", "udp6": + default: + return nil, UnknownNetworkError(net) + } + if gaddr == nil || gaddr.IP == nil { + return nil, &OpError{"listenmulticastudp", "udp", nil, errMissingAddress} + } + fd, err := internetSocket(net, gaddr.toAddr(), nil, syscall.SOCK_DGRAM, 0, "listen", sockaddrToUDP) + if err != nil { + return nil, err + } + c := newUDPConn(fd) + ip4 := gaddr.IP.To4() + if ip4 != nil { + err := listenIPv4MulticastUDP(c, ifi, ip4) + if err != nil { + c.Close() + return nil, err + } + } else { + err := listenIPv6MulticastUDP(c, ifi, gaddr.IP) + if err != nil { + c.Close() + return nil, err + } + } + return c, nil +} -// JoinGroup joins the IP multicast group named by addr on ifi, -// which specifies the interface to join. JoinGroup uses the -// default multicast interface if ifi is nil. -func (c *UDPConn) JoinGroup(ifi *Interface, addr IP) error { - if !c.ok() { - return os.EINVAL +func listenIPv4MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error { + if ifi != nil { + err := setIPv4MulticastInterface(c.fd, ifi) + if err != nil { + return err + } + } + err := setIPv4MulticastLoopback(c.fd, false) + if err != nil { + return err } - setDefaultMulticastSockopts(c.fd) - ip := addr.To4() - if ip != nil { - return joinIPv4GroupUDP(c, ifi, ip) + err = joinIPv4GroupUDP(c, ifi, ip) + if err != nil { + return err } - return joinIPv6GroupUDP(c, ifi, addr) + return nil } -// LeaveGroup exits the IP multicast group named by addr on ifi. -func (c *UDPConn) LeaveGroup(ifi *Interface, addr IP) error { - if !c.ok() { - return os.EINVAL +func listenIPv6MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error { + if ifi != nil { + err := setIPv6MulticastInterface(c.fd, ifi) + if err != nil { + return err + } } - ip := addr.To4() - if ip != nil { - return leaveIPv4GroupUDP(c, ifi, ip) + err := setIPv6MulticastLoopback(c.fd, false) + if err != nil { + return err } - return leaveIPv6GroupUDP(c, ifi, addr) + err = joinIPv6GroupUDP(c, ifi, ip) + if err != nil { + return err + } + return nil } func joinIPv4GroupUDP(c *UDPConn, ifi *Interface, ip IP) error { -- 2.50.0