Add /proc/net/* files

Updates #1195

PiperOrigin-RevId: 290285420

pkg/sentry/fsimpl/proc/BUILD

@@ -18,7 +18,6 @@ go_library(
     importpath = "gvisor.dev/gvisor/pkg/sentry/fsimpl/proc",
     deps = [
         "//pkg/abi/linux",
-        "//pkg/binary",
         "//pkg/log",
         "//pkg/sentry/context",
         "//pkg/sentry/fs",
@@ -37,6 +36,7 @@ go_library(
         "//pkg/sentry/usermem",
         "//pkg/sentry/vfs",
         "//pkg/syserror",
+        "//pkg/tcpip/header",
     ],
 )
 

pkg/sentry/fsimpl/proc/tasks.go

@@ -67,6 +67,7 @@ func newTasksInode(inoGen InoGenerator, k *kernel.Kernel, pidns *kernel.PIDNames
 		"sys":     newSysDir(root, inoGen),
 		"meminfo": newDentry(root, inoGen.NextIno(), 0444, &meminfoData{}),
 		"mounts":  kernfs.NewStaticSymlink(root, inoGen.NextIno(), "self/mounts"),
+		"net":     newNetDir(root, inoGen, k),
 		"stat":    newDentry(root, inoGen.NextIno(), 0444, &statData{}),
 		"uptime":  newDentry(root, inoGen.NextIno(), 0444, &uptimeData{}),
 		"version": newDentry(root, inoGen.NextIno(), 0444, &versionData{}),

pkg/sentry/fsimpl/proc/tasks_sys_test.go

@@ -31,7 +31,7 @@ func newIPv6TestStack() *inet.TestStack {
 }
 
 func TestIfinet6NoAddresses(t *testing.T) {
-	n := &ifinet6{s: newIPv6TestStack()}
+	n := &ifinet6{stack: newIPv6TestStack()}
 	var buf bytes.Buffer
 	n.Generate(contexttest.Context(t), &buf)
 	if buf.Len() > 0 {
@@ -62,7 +62,7 @@ func TestIfinet6(t *testing.T) {
 		"101112131415161718191a1b1c1d1e1f 02 80 00 00     eth1\n": {},
 	}
 
-	n := &ifinet6{s: s}
+	n := &ifinet6{stack: s}
 	contents := n.contents()
 	if len(contents) != len(want) {
 		t.Errorf("Got len(n.contents()) = %d, want = %d", len(contents), len(want))

pkg/sentry/fsimpl/proc/tasks_test.go

@@ -73,6 +73,7 @@ func checkTasksStaticFiles(gots []vfs.Dirent) ([]vfs.Dirent, error) {
 		"loadavg":     {Type: linux.DT_REG},
 		"meminfo":     {Type: linux.DT_REG},
 		"mounts":      {Type: linux.DT_LNK},
+		"net":         {Type: linux.DT_DIR},
 		"self":        selfLink,
 		"stat":        {Type: linux.DT_REG},
 		"sys":         {Type: linux.DT_DIR},