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authorGhanan Gowripalan <ghanan@google.com>2020-07-30 12:48:18 -0700
committergVisor bot <gvisor-bot@google.com>2020-07-30 12:50:02 -0700
commitb00858d075fbc39c6fb2db9f903ac14f197566bd (patch)
tree30bcd5acc64d5f90e78d09429f5b8255c0e6141f
parentbc8201d01bc98e9db4009d250454c5fe73c5d2b4 (diff)
Use brodcast MAC for broadcast IPv4 packets
When sending packets to a known network's broadcast address, use the broadcast MAC address. Test: - stack_test.TestOutgoingSubnetBroadcast - udp_test.TestOutgoingSubnetBroadcast PiperOrigin-RevId: 324062407
-rw-r--r--pkg/tcpip/stack/BUILD1
-rw-r--r--pkg/tcpip/stack/route.go10
-rw-r--r--pkg/tcpip/stack/stack.go15
-rw-r--r--pkg/tcpip/stack/stack_test.go223
-rw-r--r--pkg/tcpip/tcpip.go26
-rw-r--r--pkg/tcpip/transport/udp/endpoint.go8
-rw-r--r--pkg/tcpip/transport/udp/udp_test.go189
7 files changed, 464 insertions, 8 deletions
diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD
index 6b9a6b316..2b4455318 100644
--- a/pkg/tcpip/stack/BUILD
+++ b/pkg/tcpip/stack/BUILD
@@ -110,6 +110,7 @@ go_test(
"//pkg/tcpip/transport/udp",
"//pkg/waiter",
"@com_github_google_go_cmp//cmp:go_default_library",
+ "@com_github_google_go_cmp//cmp/cmpopts:go_default_library",
],
)
diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go
index d65f8049e..91e0110f1 100644
--- a/pkg/tcpip/stack/route.go
+++ b/pkg/tcpip/stack/route.go
@@ -48,6 +48,10 @@ type Route struct {
// Loop controls where WritePacket should send packets.
Loop PacketLooping
+
+ // directedBroadcast indicates whether this route is sending a directed
+ // broadcast packet.
+ directedBroadcast bool
}
// makeRoute initializes a new route. It takes ownership of the provided
@@ -275,6 +279,12 @@ func (r *Route) Stack() *Stack {
return r.ref.stack()
}
+// IsBroadcast returns true if the route is to send a broadcast packet.
+func (r *Route) IsBroadcast() bool {
+ // Only IPv4 has a notion of broadcast.
+ return r.directedBroadcast || r.RemoteAddress == header.IPv4Broadcast
+}
+
// ReverseRoute returns new route with given source and destination address.
func (r *Route) ReverseRoute(src tcpip.Address, dst tcpip.Address) Route {
return Route{
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index a6faa22c2..36626e051 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1284,9 +1284,9 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
s.mu.RLock()
defer s.mu.RUnlock()
- isBroadcast := remoteAddr == header.IPv4Broadcast
+ isLocalBroadcast := remoteAddr == header.IPv4Broadcast
isMulticast := header.IsV4MulticastAddress(remoteAddr) || header.IsV6MulticastAddress(remoteAddr)
- needRoute := !(isBroadcast || isMulticast || header.IsV6LinkLocalAddress(remoteAddr))
+ needRoute := !(isLocalBroadcast || isMulticast || header.IsV6LinkLocalAddress(remoteAddr))
if id != 0 && !needRoute {
if nic, ok := s.nics[id]; ok && nic.enabled() {
if ref := s.getRefEP(nic, localAddr, remoteAddr, netProto); ref != nil {
@@ -1307,9 +1307,16 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
}
r := makeRoute(netProto, ref.ep.ID().LocalAddress, remoteAddr, nic.linkEP.LinkAddress(), ref, s.handleLocal && !nic.isLoopback(), multicastLoop && !nic.isLoopback())
- if needRoute {
- r.NextHop = route.Gateway
+ r.directedBroadcast = route.Destination.IsBroadcast(remoteAddr)
+
+ if len(route.Gateway) > 0 {
+ if needRoute {
+ r.NextHop = route.Gateway
+ }
+ } else if r.directedBroadcast {
+ r.RemoteLinkAddress = header.EthernetBroadcastAddress
}
+
return r, nil
}
}
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 101ca2206..f22062889 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -27,6 +27,7 @@ import (
"time"
"github.com/google/go-cmp/cmp"
+ "github.com/google/go-cmp/cmp/cmpopts"
"gvisor.dev/gvisor/pkg/rand"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
@@ -3418,3 +3419,225 @@ func TestStackSendBufferSizeOption(t *testing.T) {
})
}
}
+
+func TestOutgoingSubnetBroadcast(t *testing.T) {
+ const (
+ unspecifiedNICID = 0
+ nicID1 = 1
+ )
+
+ defaultAddr := tcpip.AddressWithPrefix{
+ Address: header.IPv4Any,
+ PrefixLen: 0,
+ }
+ defaultSubnet := defaultAddr.Subnet()
+ ipv4Addr := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 24,
+ }
+ ipv4Subnet := ipv4Addr.Subnet()
+ ipv4SubnetBcast := ipv4Subnet.Broadcast()
+ ipv4Gateway := tcpip.Address("\xc0\xa8\x01\x01")
+ ipv4AddrPrefix31 := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 31,
+ }
+ ipv4Subnet31 := ipv4AddrPrefix31.Subnet()
+ ipv4Subnet31Bcast := ipv4Subnet31.Broadcast()
+ ipv4AddrPrefix32 := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 32,
+ }
+ ipv4Subnet32 := ipv4AddrPrefix32.Subnet()
+ ipv4Subnet32Bcast := ipv4Subnet32.Broadcast()
+ ipv6Addr := tcpip.AddressWithPrefix{
+ Address: "\x20\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ PrefixLen: 64,
+ }
+ ipv6Subnet := ipv6Addr.Subnet()
+ ipv6SubnetBcast := ipv6Subnet.Broadcast()
+ remNetAddr := tcpip.AddressWithPrefix{
+ Address: "\x64\x0a\x7b\x18",
+ PrefixLen: 24,
+ }
+ remNetSubnet := remNetAddr.Subnet()
+ remNetSubnetBcast := remNetSubnet.Broadcast()
+
+ tests := []struct {
+ name string
+ nicAddr tcpip.ProtocolAddress
+ routes []tcpip.Route
+ remoteAddr tcpip.Address
+ expectedRoute stack.Route
+ }{
+ // Broadcast to a locally attached subnet populates the broadcast MAC.
+ {
+ name: "IPv4 Broadcast to local subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4SubnetBcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4Addr.Address,
+ RemoteAddress: ipv4SubnetBcast,
+ RemoteLinkAddress: header.EthernetBroadcastAddress,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // Broadcast to a locally attached /31 subnet does not populate the
+ // broadcast MAC.
+ {
+ name: "IPv4 Broadcast to local /31 subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4AddrPrefix31,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet31,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4Subnet31Bcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4AddrPrefix31.Address,
+ RemoteAddress: ipv4Subnet31Bcast,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // Broadcast to a locally attached /32 subnet does not populate the
+ // broadcast MAC.
+ {
+ name: "IPv4 Broadcast to local /32 subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4AddrPrefix32,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet32,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4Subnet32Bcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4AddrPrefix32.Address,
+ RemoteAddress: ipv4Subnet32Bcast,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // IPv6 has no notion of a broadcast.
+ {
+ name: "IPv6 'Broadcast' to local subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv6ProtocolNumber,
+ AddressWithPrefix: ipv6Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv6Subnet,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv6SubnetBcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv6Addr.Address,
+ RemoteAddress: ipv6SubnetBcast,
+ NetProto: header.IPv6ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // Broadcast to a remote subnet in the route table is send to the next-hop
+ // gateway.
+ {
+ name: "IPv4 Broadcast to remote subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: remNetSubnet,
+ Gateway: ipv4Gateway,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: remNetSubnetBcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4Addr.Address,
+ RemoteAddress: remNetSubnetBcast,
+ NextHop: ipv4Gateway,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ // Broadcast to an unknown subnet follows the default route. Note that this
+ // is essentially just routing an unknown destination IP, because w/o any
+ // subnet prefix information a subnet broadcast address is just a normal IP.
+ {
+ name: "IPv4 Broadcast to unknown subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: defaultSubnet,
+ Gateway: ipv4Gateway,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: remNetSubnetBcast,
+ expectedRoute: stack.Route{
+ LocalAddress: ipv4Addr.Address,
+ RemoteAddress: remNetSubnetBcast,
+ NextHop: ipv4Gateway,
+ NetProto: header.IPv4ProtocolNumber,
+ Loop: stack.PacketOut,
+ },
+ },
+ }
+
+ for _, test := range tests {
+ t.Run(test.name, func(t *testing.T) {
+ s := stack.New(stack.Options{
+ NetworkProtocols: []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
+ })
+ ep := channel.New(0, defaultMTU, "")
+ if err := s.CreateNIC(nicID1, ep); err != nil {
+ t.Fatalf("CreateNIC(%d, _): %s", nicID1, err)
+ }
+ if err := s.AddProtocolAddress(nicID1, test.nicAddr); err != nil {
+ t.Fatalf("AddProtocolAddress(%d, %+v): %s", nicID1, test.nicAddr, err)
+ }
+
+ s.SetRouteTable(test.routes)
+
+ var netProto tcpip.NetworkProtocolNumber
+ switch l := len(test.remoteAddr); l {
+ case header.IPv4AddressSize:
+ netProto = header.IPv4ProtocolNumber
+ case header.IPv6AddressSize:
+ netProto = header.IPv6ProtocolNumber
+ default:
+ t.Fatalf("got unexpected address length = %d bytes", l)
+ }
+
+ if r, err := s.FindRoute(unspecifiedNICID, "" /* localAddr */, test.remoteAddr, netProto, false /* multicastLoop */); err != nil {
+ t.Fatalf("FindRoute(%d, '', %s, %d): %s", unspecifiedNICID, test.remoteAddr, netProto, err)
+ } else if diff := cmp.Diff(r, test.expectedRoute, cmpopts.IgnoreUnexported(r)); diff != "" {
+ t.Errorf("route mismatch (-want +got):\n%s", diff)
+ }
+ })
+ }
+}
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 21aafb0a2..a634b9b60 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -43,6 +43,9 @@ import (
"gvisor.dev/gvisor/pkg/waiter"
)
+// Using header.IPv4AddressSize would cause an import cycle.
+const ipv4AddressSize = 4
+
// Error represents an error in the netstack error space. Using a special type
// ensures that errors outside of this space are not accidentally introduced.
//
@@ -320,6 +323,29 @@ func (s *Subnet) Broadcast() Address {
return Address(addr)
}
+// IsBroadcast returns true if the address is considered a broadcast address.
+func (s *Subnet) IsBroadcast(address Address) bool {
+ // Only IPv4 supports the notion of a broadcast address.
+ if len(address) != ipv4AddressSize {
+ return false
+ }
+
+ // Normally, we would just compare address with the subnet's broadcast
+ // address but there is an exception where a simple comparison is not
+ // correct. This exception is for /31 and /32 IPv4 subnets where all
+ // addresses are considered valid host addresses.
+ //
+ // For /31 subnets, the case is easy. RFC 3021 Section 2.1 states that
+ // both addresses in a /31 subnet "MUST be interpreted as host addresses."
+ //
+ // For /32, the case is a bit more vague. RFC 3021 makes no mention of /32
+ // subnets. However, the same reasoning applies - if an exception is not
+ // made, then there do not exist any host addresses in a /32 subnet. RFC
+ // 4632 Section 3.1 also vaguely implies this interpretation by referring
+ // to addresses in /32 subnets as "host routes."
+ return s.Prefix() <= 30 && s.Broadcast() == address
+}
+
// Equal returns true if s equals o.
//
// Needed to use cmp.Equal on Subnet as its fields are unexported.
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 6e692da07..b7d735889 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -483,10 +483,6 @@ func (e *endpoint) write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-c
nicID = e.BindNICID
}
- if to.Addr == header.IPv4Broadcast && !e.broadcast {
- return 0, nil, tcpip.ErrBroadcastDisabled
- }
-
dst, netProto, err := e.checkV4MappedLocked(*to)
if err != nil {
return 0, nil, err
@@ -503,6 +499,10 @@ func (e *endpoint) write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-c
resolve = route.Resolve
}
+ if !e.broadcast && route.IsBroadcast() {
+ return 0, nil, tcpip.ErrBroadcastDisabled
+ }
+
if route.IsResolutionRequired() {
if ch, err := resolve(nil); err != nil {
if err == tcpip.ErrWouldBlock {
diff --git a/pkg/tcpip/transport/udp/udp_test.go b/pkg/tcpip/transport/udp/udp_test.go
index 90781cf49..66e8911c8 100644
--- a/pkg/tcpip/transport/udp/udp_test.go
+++ b/pkg/tcpip/transport/udp/udp_test.go
@@ -2142,3 +2142,192 @@ func (c *testContext) checkEndpointReadStats(incr uint64, want tcpip.TransportEn
c.t.Errorf("Endpoint stats not matching for error %s got %+v want %+v", err, got, want)
}
}
+
+func TestOutgoingSubnetBroadcast(t *testing.T) {
+ const nicID1 = 1
+
+ ipv4Addr := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 24,
+ }
+ ipv4Subnet := ipv4Addr.Subnet()
+ ipv4SubnetBcast := ipv4Subnet.Broadcast()
+ ipv4Gateway := tcpip.Address("\xc0\xa8\x01\x01")
+ ipv4AddrPrefix31 := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 31,
+ }
+ ipv4Subnet31 := ipv4AddrPrefix31.Subnet()
+ ipv4Subnet31Bcast := ipv4Subnet31.Broadcast()
+ ipv4AddrPrefix32 := tcpip.AddressWithPrefix{
+ Address: "\xc0\xa8\x01\x3a",
+ PrefixLen: 32,
+ }
+ ipv4Subnet32 := ipv4AddrPrefix32.Subnet()
+ ipv4Subnet32Bcast := ipv4Subnet32.Broadcast()
+ ipv6Addr := tcpip.AddressWithPrefix{
+ Address: "\x20\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01",
+ PrefixLen: 64,
+ }
+ ipv6Subnet := ipv6Addr.Subnet()
+ ipv6SubnetBcast := ipv6Subnet.Broadcast()
+ remNetAddr := tcpip.AddressWithPrefix{
+ Address: "\x64\x0a\x7b\x18",
+ PrefixLen: 24,
+ }
+ remNetSubnet := remNetAddr.Subnet()
+ remNetSubnetBcast := remNetSubnet.Broadcast()
+
+ tests := []struct {
+ name string
+ nicAddr tcpip.ProtocolAddress
+ routes []tcpip.Route
+ remoteAddr tcpip.Address
+ requiresBroadcastOpt bool
+ }{
+ {
+ name: "IPv4 Broadcast to local subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4SubnetBcast,
+ requiresBroadcastOpt: true,
+ },
+ {
+ name: "IPv4 Broadcast to local /31 subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4AddrPrefix31,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet31,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4Subnet31Bcast,
+ requiresBroadcastOpt: false,
+ },
+ {
+ name: "IPv4 Broadcast to local /32 subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4AddrPrefix32,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv4Subnet32,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv4Subnet32Bcast,
+ requiresBroadcastOpt: false,
+ },
+ // IPv6 has no notion of a broadcast.
+ {
+ name: "IPv6 'Broadcast' to local subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv6ProtocolNumber,
+ AddressWithPrefix: ipv6Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: ipv6Subnet,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: ipv6SubnetBcast,
+ requiresBroadcastOpt: false,
+ },
+ {
+ name: "IPv4 Broadcast to remote subnet",
+ nicAddr: tcpip.ProtocolAddress{
+ Protocol: header.IPv4ProtocolNumber,
+ AddressWithPrefix: ipv4Addr,
+ },
+ routes: []tcpip.Route{
+ {
+ Destination: remNetSubnet,
+ Gateway: ipv4Gateway,
+ NIC: nicID1,
+ },
+ },
+ remoteAddr: remNetSubnetBcast,
+ requiresBroadcastOpt: true,
+ },
+ }
+
+ for _, test := range tests {
+ t.Run(test.name, func(t *testing.T) {
+ s := stack.New(stack.Options{
+ NetworkProtocols: []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
+
+ TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()},
+ })
+ e := channel.New(0, defaultMTU, "")
+ if err := s.CreateNIC(nicID1, e); err != nil {
+ t.Fatalf("CreateNIC(%d, _): %s", nicID1, err)
+ }
+ if err := s.AddProtocolAddress(nicID1, test.nicAddr); err != nil {
+ t.Fatalf("AddProtocolAddress(%d, %+v): %s", nicID1, test.nicAddr, err)
+ }
+
+ s.SetRouteTable(test.routes)
+
+ var netProto tcpip.NetworkProtocolNumber
+ switch l := len(test.remoteAddr); l {
+ case header.IPv4AddressSize:
+ netProto = header.IPv4ProtocolNumber
+ case header.IPv6AddressSize:
+ netProto = header.IPv6ProtocolNumber
+ default:
+ t.Fatalf("got unexpected address length = %d bytes", l)
+ }
+
+ wq := waiter.Queue{}
+ ep, err := s.NewEndpoint(udp.ProtocolNumber, netProto, &wq)
+ if err != nil {
+ t.Fatalf("NewEndpoint(%d, %d, _): %s", udp.ProtocolNumber, netProto, err)
+ }
+ defer ep.Close()
+
+ data := tcpip.SlicePayload([]byte{1, 2, 3, 4})
+ to := tcpip.FullAddress{
+ Addr: test.remoteAddr,
+ Port: 80,
+ }
+ opts := tcpip.WriteOptions{To: &to}
+ expectedErrWithoutBcastOpt := tcpip.ErrBroadcastDisabled
+ if !test.requiresBroadcastOpt {
+ expectedErrWithoutBcastOpt = nil
+ }
+
+ if n, _, err := ep.Write(data, opts); err != expectedErrWithoutBcastOpt {
+ t.Fatalf("got ep.Write(_, _) = (%d, _, %v), want = (_, _, %v)", n, err, expectedErrWithoutBcastOpt)
+ }
+
+ if err := ep.SetSockOptBool(tcpip.BroadcastOption, true); err != nil {
+ t.Fatalf("got SetSockOptBool(BroadcastOption, true): %s", err)
+ }
+
+ if n, _, err := ep.Write(data, opts); err != nil {
+ t.Fatalf("got ep.Write(_, _) = (%d, _, %s), want = (_, _, nil)", n, err)
+ }
+
+ if err := ep.SetSockOptBool(tcpip.BroadcastOption, false); err != nil {
+ t.Fatalf("got SetSockOptBool(BroadcastOption, false): %s", err)
+ }
+
+ if n, _, err := ep.Write(data, opts); err != expectedErrWithoutBcastOpt {
+ t.Fatalf("got ep.Write(_, _) = (%d, _, %v), want = (_, _, %v)", n, err, expectedErrWithoutBcastOpt)
+ }
+ })
+ }
+}