Fix minor bugs in a couple of interface IOCTLs.

gVisor incorrectly returns the wrong ARP type for SIOGIFHWADDR. This breaks
tcpdump as it tries to interpret the packets incorrectly.

Similarly, SIOCETHTOOL is used by tcpdump to query interface properties which
fails with an EINVAL since we don't implement it. For now change it to return
EOPNOTSUPP to indicate that we don't support the query rather than return
EINVAL.

NOTE: ARPHRD types for link endpoints are distinct from NIC capabilities
and NIC flags. In Linux all 3 exist eg. ARPHRD types are stored in dev->type
field while NIC capabilities are more like the device features which can be
queried using SIOCETHTOOL but not modified and NIC Flags are fields that can
be modified from user space. eg. NIC status (UP/DOWN/MULTICAST/BROADCAST) etc.

Updates #2746

PiperOrigin-RevId: 321436525

15 files changed, 70 insertions, 0 deletions

diff --git a/pkg/tcpip/link/channel/BUILD b/pkg/tcpip/link/channel/BUILD
index b8b93e78e..39ca774ef 100644
--- a/pkg/tcpip/link/channel/BUILD
+++ b/pkg/tcpip/link/channel/BUILD
@@ -10,6 +10,7 @@ go_library(
         "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/header",
         "//pkg/tcpip/stack",
     ],
 )
diff --git a/pkg/tcpip/link/channel/channel.go b/pkg/tcpip/link/channel/channel.go
index 20b183da0..a2bb773d4 100644
--- a/pkg/tcpip/link/channel/channel.go
+++ b/pkg/tcpip/link/channel/channel.go
@@ -23,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -296,3 +297,8 @@ func (e *Endpoint) AddNotify(notify Notification) *NotificationHandle {
 func (e *Endpoint) RemoveNotify(handle *NotificationHandle) {
 	e.q.RemoveNotify(handle)
 }
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
+func (*Endpoint) ARPHardwareType() header.ARPHardwareType {
+	return header.ARPHardwareNone
+}
diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index f34082e1a..32abe2a13 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/pkg/tcpip/link/fdbased/endpoint.go
@@ -626,6 +626,14 @@ func (e *endpoint) GSOMaxSize() uint32 {
 	return e.gsoMaxSize
 }
 
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
+func (e *endpoint) ARPHardwareType() header.ARPHardwareType {
+	if e.hdrSize > 0 {
+		return header.ARPHardwareEther
+	}
+	return header.ARPHardwareNone
+}
+
 // InjectableEndpoint is an injectable fd-based endpoint. The endpoint writes
 // to the FD, but does not read from it. All reads come from injected packets.
 type InjectableEndpoint struct {
diff --git a/pkg/tcpip/link/loopback/loopback.go b/pkg/tcpip/link/loopback/loopback.go
index 568c6874f..3b17d8c28 100644
--- a/pkg/tcpip/link/loopback/loopback.go
+++ b/pkg/tcpip/link/loopback/loopback.go
@@ -113,3 +113,8 @@ func (e *endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error {
 
 	return nil
 }
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
+func (*endpoint) ARPHardwareType() header.ARPHardwareType {
+	return header.ARPHardwareLoopback
+}
diff --git a/pkg/tcpip/link/muxed/BUILD b/pkg/tcpip/link/muxed/BUILD
index 82b441b79..e7493e5c5 100644
--- a/pkg/tcpip/link/muxed/BUILD
+++ b/pkg/tcpip/link/muxed/BUILD
@@ -9,6 +9,7 @@ go_library(
     deps = [
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/header",
         "//pkg/tcpip/stack",
     ],
 )
diff --git a/pkg/tcpip/link/muxed/injectable.go b/pkg/tcpip/link/muxed/injectable.go
index c69d6b7e9..c305d9e86 100644
--- a/pkg/tcpip/link/muxed/injectable.go
+++ b/pkg/tcpip/link/muxed/injectable.go
@@ -18,6 +18,7 @@ package muxed
 import (
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -129,6 +130,11 @@ func (m *InjectableEndpoint) Wait() {
 	}
 }
 
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
+func (*InjectableEndpoint) ARPHardwareType() header.ARPHardwareType {
+	panic("unsupported operation")
+}
+
 // NewInjectableEndpoint creates a new multi-endpoint injectable endpoint.
 func NewInjectableEndpoint(routes map[tcpip.Address]stack.InjectableLinkEndpoint) *InjectableEndpoint {
 	return &InjectableEndpoint{
diff --git a/pkg/tcpip/link/nested/BUILD b/pkg/tcpip/link/nested/BUILD
index bdd5276ad..2cdb23475 100644
--- a/pkg/tcpip/link/nested/BUILD
+++ b/pkg/tcpip/link/nested/BUILD
@@ -12,6 +12,7 @@ go_library(
         "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/header",
         "//pkg/tcpip/stack",
     ],
 )
diff --git a/pkg/tcpip/link/nested/nested.go b/pkg/tcpip/link/nested/nested.go
index 2998f9c4f..328bd048e 100644
--- a/pkg/tcpip/link/nested/nested.go
+++ b/pkg/tcpip/link/nested/nested.go
@@ -20,6 +20,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -129,3 +130,8 @@ func (e *Endpoint) GSOMaxSize() uint32 {
 	}
 	return 0
 }
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType
+func (e *Endpoint) ARPHardwareType() header.ARPHardwareType {
+	return e.child.ARPHardwareType()
+}
diff --git a/pkg/tcpip/link/qdisc/fifo/BUILD b/pkg/tcpip/link/qdisc/fifo/BUILD
index 054c213bc..1d0079bd6 100644
--- a/pkg/tcpip/link/qdisc/fifo/BUILD
+++ b/pkg/tcpip/link/qdisc/fifo/BUILD
@@ -14,6 +14,7 @@ go_library(
         "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/header",
         "//pkg/tcpip/stack",
     ],
 )
diff --git a/pkg/tcpip/link/qdisc/fifo/endpoint.go b/pkg/tcpip/link/qdisc/fifo/endpoint.go
index b5dfb7850..c84fe1bb9 100644
--- a/pkg/tcpip/link/qdisc/fifo/endpoint.go
+++ b/pkg/tcpip/link/qdisc/fifo/endpoint.go
@@ -22,6 +22,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -207,3 +208,8 @@ func (e *endpoint) Wait() {
 
 	e.wg.Wait()
 }
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType
+func (e *endpoint) ARPHardwareType() header.ARPHardwareType {
+	return e.lower.ARPHardwareType()
+}
diff --git a/pkg/tcpip/link/sharedmem/sharedmem.go b/pkg/tcpip/link/sharedmem/sharedmem.go
index 0374a2441..a36862c67 100644
--- a/pkg/tcpip/link/sharedmem/sharedmem.go
+++ b/pkg/tcpip/link/sharedmem/sharedmem.go
@@ -287,3 +287,8 @@ func (e *endpoint) dispatchLoop(d stack.NetworkDispatcher) {
 
 	e.completed.Done()
 }
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType
+func (*endpoint) ARPHardwareType() header.ARPHardwareType {
+	return header.ARPHardwareEther
+}
diff --git a/pkg/tcpip/link/tun/device.go b/pkg/tcpip/link/tun/device.go
index 6bc9033d0..47446efec 100644
--- a/pkg/tcpip/link/tun/device.go
+++ b/pkg/tcpip/link/tun/device.go
@@ -139,6 +139,7 @@ func attachOrCreateNIC(s *stack.Stack, name, prefix string, linkCaps stack.LinkE
 			stack:    s,
 			nicID:    id,
 			name:     name,
+			isTap:    prefix == "tap",
 		}
 		endpoint.Endpoint.LinkEPCapabilities = linkCaps
 		if endpoint.name == "" {
@@ -348,6 +349,7 @@ type tunEndpoint struct {
 	stack *stack.Stack
 	nicID tcpip.NICID
 	name  string
+	isTap bool
 }
 
 // DecRef decrements refcount of e, removes NIC if refcount goes to 0.
@@ -356,3 +358,11 @@ func (e *tunEndpoint) DecRef() {
 		e.stack.RemoveNIC(e.nicID)
 	})
 }
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
+func (e *tunEndpoint) ARPHardwareType() header.ARPHardwareType {
+	if e.isTap {
+		return header.ARPHardwareEther
+	}
+	return header.ARPHardwareNone
+}
diff --git a/pkg/tcpip/link/waitable/BUILD b/pkg/tcpip/link/waitable/BUILD
index 0956d2c65..ee84c3d96 100644
--- a/pkg/tcpip/link/waitable/BUILD
+++ b/pkg/tcpip/link/waitable/BUILD
@@ -12,6 +12,7 @@ go_library(
         "//pkg/gate",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/header",
         "//pkg/tcpip/stack",
     ],
 )
@@ -25,6 +26,7 @@ go_test(
     deps = [
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/header",
         "//pkg/tcpip/stack",
     ],
 )
diff --git a/pkg/tcpip/link/waitable/waitable.go b/pkg/tcpip/link/waitable/waitable.go
index 949b3f2b2..24a8dc2eb 100644
--- a/pkg/tcpip/link/waitable/waitable.go
+++ b/pkg/tcpip/link/waitable/waitable.go
@@ -25,6 +25,7 @@ import (
 	"gvisor.dev/gvisor/pkg/gate"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -147,3 +148,8 @@ func (e *Endpoint) WaitDispatch() {
 
 // Wait implements stack.LinkEndpoint.Wait.
 func (e *Endpoint) Wait() {}
+
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
+func (e *Endpoint) ARPHardwareType() header.ARPHardwareType {
+	return e.lower.ARPHardwareType()
+}
diff --git a/pkg/tcpip/link/waitable/waitable_test.go b/pkg/tcpip/link/waitable/waitable_test.go
index 63bf40562..ffb2354be 100644
--- a/pkg/tcpip/link/waitable/waitable_test.go
+++ b/pkg/tcpip/link/waitable/waitable_test.go
@@ -19,6 +19,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -81,6 +82,11 @@ func (e *countedEndpoint) WriteRawPacket(buffer.VectorisedView) *tcpip.Error {
 	return nil
 }
 
+// ARPHardwareType implements stack.LinkEndpoint.ARPHardwareType.
+func (*countedEndpoint) ARPHardwareType() header.ARPHardwareType {
+	panic("unimplemented")
+}
+
 // Wait implements stack.LinkEndpoint.Wait.
 func (*countedEndpoint) Wait() {}