tun: Initial skeleton for tun support

There will be two entities handled:

1. tun file -- an opened char device with misc major and tun minor
   that can be attached to item #2

2. tun netdevice -- another type of links
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Makefile.crtools

@@ -5,6 +5,7 @@ obj-y	+= crtools.o
 obj-y	+= image.o
 obj-y	+= image-desc.o
 obj-y	+= net.o
+obj-y	+= tun.o
 obj-y	+= proc_parse.o
 obj-y	+= cr-dump.o
 obj-y	+= cr-show.o

image-desc.c

@@ -74,6 +74,7 @@ struct cr_fd_desc_tmpl fdset_template[CR_FD_MAX] = {
 	FD_ENTRY(SHM_PAGES_OLD, "pages-shmem-%ld",	NULL),
 	FD_ENTRY(SIGNAL,	"signal-s-%d",		show_siginfo), /* shared signals */
 	FD_ENTRY(PSIGNAL,	"signal-p-%d",		show_siginfo), /* private signals */
+	FD_ENTRY(TUNFILE,	"tunfile",		show_tunfile),
 
 	[CR_FD_STATS] = {
 		.fmt	= "stats-%s",

include/cr-show.h

@@ -51,5 +51,6 @@ extern void show_tcp_stream(int fd);
 extern void show_mountpoints(int fd);
 extern void show_netdevices(int fd);
 extern void show_stats(int fd);
+extern void show_tunfile(int fd);
 
 #endif /* __CR_SHOW_H__ */

include/image-desc.h

@@ -72,6 +72,7 @@ enum {
 	CR_FD_INOTIFY_WD,
 	CR_FD_FANOTIFY,
 	CR_FD_FANOTIFY_MARK,
+	CR_FD_TUNFILE,
 	_CR_FD_GLOB_TO,
 
 	CR_FD_TMPFS,

include/magic.h

@@ -70,6 +70,7 @@
 #define PSIGNAL_MAGIC		SIGNAL_MAGIC
 #define NETLINKSK_MAGIC		0x58005614 /* Perm */
 #define NS_FILES_MAGIC		0x61394011 /* Nyandoma */
+#define TUNFILE_MAGIC		0x57143751 /* Kalyazin */
 
 #define IFADDR_MAGIC		RAW_IMAGE_MAGIC
 #define ROUTE_MAGIC		RAW_IMAGE_MAGIC

include/protobuf-desc.h

@@ -54,6 +54,7 @@ enum {
 	PB_PAGEMAP_HEAD,
 	PB_PAGEMAP,
 	PB_SIGINFO,
+	PB_TUNFILE,
 
 	PB_MAX
 };

include/tun.h

+#ifndef __CR_TUN_H__
+#define __CR_TUN_H__
+#ifndef TUN_MINOR
+#define TUN_MINOR	200
+#endif
+#endif

protobuf-desc.c

@@ -55,6 +55,7 @@
 #include "protobuf/siginfo.pb-c.h"
 #include "protobuf/sk-netlink.pb-c.h"
 #include "protobuf/vma.pb-c.h"
+#include "protobuf/tun.pb-c.h"
 
 struct cr_pb_message_desc cr_pb_descs[PB_MAX];
 
@@ -137,4 +138,6 @@ void cr_pb_init(void)
 	CR_PB_DESC(PAGEMAP,		Pagemap,	pagemap);
 	CR_PB_DESC(SIGINFO,		Siginfo,	siginfo);
 	CR_PB_DESC(NETLINKSK,		NetlinkSk,	netlink_sk);
+
+	CR_PB_DESC(TUNFILE,		Tunfile,	tunfile);
 }

protobuf/Makefile

@@ -39,6 +39,7 @@ proto-obj-y	+= mm.o
 proto-obj-y	+= sk-opts.o
 proto-obj-y	+= sk-unix.o
 proto-obj-y	+= sk-inet.o
+proto-obj-y	+= tun.o
 proto-obj-y	+= sk-netlink.o
 proto-obj-y	+= packet-sock.o
 proto-obj-y	+= ipc-var.o

protobuf/fdinfo.proto

@@ -14,6 +14,7 @@ enum fd_types {
 	FANOTIFY	= 12;
 	NETLINKSK	= 13;
 	NS		= 14;
+	TUN		= 15;
 }
 
 message fdinfo_entry {

protobuf/netdev.proto

+import "tun.proto";
+
 enum nd_type {
 	LOOPBACK	= 1;
 	VETH		= 2;
+	TUN		= 3;
 }
 
 message net_device_entry {
@@ -9,4 +12,6 @@ message net_device_entry {
 	required uint32  mtu		= 3;
 	required uint32  flags		= 4;
 	required string  name		= 5;
+
+	optional tun_link_entry tun	= 6;
 }

protobuf/tun.proto

+import "fown.proto";
+
+message tunfile_entry {
+	required uint32		id		= 1;
+	optional string		netdev		= 2;
+	optional bool		detached	= 3;
+};
+
+message tun_link_entry {
+	required uint32		flags = 1;
+	required int32		owner = 2;
+	required int32		group = 3;
+	required uint32		vnethdr = 4;
+	required uint32		sndbuf = 5;
+};

tun.c

+#include <unistd.h>
+#include <sys/socket.h>
+#include <linux/if.h>
+#include <linux/if_tun.h>
+#include <sys/ioctl.h>
+
+#include "crtools.h"
+#include "protobuf.h"
+#include "cr-show.h"
+#include "files.h"
+#include "files-reg.h"
+#include "tun.h"
+#include "net.h"
+
+#include "protobuf/tun.pb-c.h"
+
+#ifndef IFF_PERSIST
+#define IFF_PERSIST 0x0800
+#endif
+
+#ifndef IFF_NOFILTER
+#define IFF_NOFILTER 0x1000
+#endif
+
+#ifndef TUNSETQUEUE
+#define TUNSETQUEUE  _IOW('T', 217, int)
+#define IFF_ATTACH_QUEUE 0x0200
+#define IFF_DETACH_QUEUE 0x0400
+#endif
+
+/*
+ * Absense of the 1st ioctl means we cannot restore tun link. But
+ * since the 2nd one appeared at the same time, we'll "check" this
+ * by trying to dump filter and abort dump if it's not there.
+ */
+
+#ifndef TUNSETIFINDEX
+#define TUNSETIFINDEX _IOW('T', 218, unsigned int)
+#endif
+
+#ifndef TUNGETFILTER
+#define TUNGETFILTER _IOR('T', 219, struct sock_fprog)
+#endif
+
+#define TUN_DEV_GEN_PATH	"/dev/net/tun"
+
+void show_tunfile(int fd)
+{
+	pb_show_plain(fd, PB_TUNFILE);
+}