Update vfs2 socket TODOs.

Three updates:
- Mark all vfs2 socket syscalls as supported.
- Use the same dev number and ino number generator for all types of sockets,
  unlike in VFS1.
- Do not use host fd for hostinet metadata.

Fixes #1476, #1478, #1484, 1485, #2017.

PiperOrigin-RevId: 309994579

3 files changed, 11 insertions, 2 deletions

diff --git a/pkg/sentry/socket/hostinet/socket_vfs2.go b/pkg/sentry/socket/hostinet/socket_vfs2.go
index b03ca2f26..a8278bffc 100644
--- a/pkg/sentry/socket/hostinet/socket_vfs2.go
+++ b/pkg/sentry/socket/hostinet/socket_vfs2.go
@@ -36,8 +36,11 @@ import (
 type socketVFS2 struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl
-	// TODO(gvisor.dev/issue/1484): VFS1 stores internal metadata for hostinet.
-	// We should perhaps rely on the host, much like in hostfs.
+
+	// We store metadata for hostinet sockets internally. Technically, we should
+	// access metadata (e.g. through stat, chmod) on the host for correctness,
+	// but this is not very useful for inet socket fds, which do not belong to a
+	// concrete file anyway.
 	vfs.DentryMetadataFileDescriptionImpl
 
 	socketOpsCommon
diff --git a/pkg/sentry/socket/netstack/netstack_vfs2.go b/pkg/sentry/socket/netstack/netstack_vfs2.go
index eec71035d..f7d9b2ff4 100644
--- a/pkg/sentry/socket/netstack/netstack_vfs2.go
+++ b/pkg/sentry/socket/netstack/netstack_vfs2.go
@@ -22,6 +22,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs"
 	"gvisor.dev/gvisor/pkg/sentry/inet"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/socket"
 	"gvisor.dev/gvisor/pkg/sentry/socket/netfilter"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserr"
@@ -41,6 +42,8 @@ type SocketVFS2 struct {
 	socketOpsCommon
 }
 
+var _ = socket.SocketVFS2(&SocketVFS2{})
+
 // NewVFS2 creates a new endpoint socket.
 func NewVFS2(t *kernel.Task, family int, skType linux.SockType, protocol int, queue *waiter.Queue, endpoint tcpip.Endpoint) (*vfs.FileDescription, *syserr.Error) {
 	if skType == linux.SOCK_STREAM {
diff --git a/pkg/sentry/socket/unix/unix_vfs2.go b/pkg/sentry/socket/unix/unix_vfs2.go
index 5edc3cdf4..06d838868 100644
--- a/pkg/sentry/socket/unix/unix_vfs2.go
+++ b/pkg/sentry/socket/unix/unix_vfs2.go
@@ -22,6 +22,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/socket"
 	"gvisor.dev/gvisor/pkg/sentry/socket/control"
 	"gvisor.dev/gvisor/pkg/sentry/socket/netstack"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
@@ -43,6 +44,8 @@ type SocketVFS2 struct {
 	socketOpsCommon
 }
 
+var _ = socket.SocketVFS2(&SocketVFS2{})
+
 // NewSockfsFile creates a new socket file in the global sockfs mount and
 // returns a corresponding file description.
 func NewSockfsFile(t *kernel.Task, ep transport.Endpoint, stype linux.SockType) (*vfs.FileDescription, *syserr.Error) {