[PATCH net v3 6/9] tun: Extract the vnet handling code

[Akihiko Odaki <akihiko.odaki@daynix.com>]

The vnet handling code will be reused by tap.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 MAINTAINERS            |   2 +-
 drivers/net/Makefile   |   3 +-
 drivers/net/tun.c      | 174 +-----------------------------------------------
 drivers/net/tun_vnet.c | 175 +++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/net/tun_vnet.h |  25 +++++++
 5 files changed, 205 insertions(+), 174 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 910305c11e8a..bc32b7e23c79 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -23902,7 +23902,7 @@ W:	http://vtun.sourceforge.net/tun
 F:	Documentation/networking/tuntap.rst
 F:	arch/um/os-Linux/drivers/
 F:	drivers/net/tap.c
-F:	drivers/net/tun.c
+F:	drivers/net/tun*
 
 TURBOCHANNEL SUBSYSTEM
 M:	"Maciej W. Rozycki" <macro@orcam.me.uk>
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 13743d0e83b5..bb8eb3053772 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -29,7 +29,8 @@ obj-y += mdio/
 obj-y += pcs/
 obj-$(CONFIG_RIONET) += rionet.o
 obj-$(CONFIG_NET_TEAM) += team/
-obj-$(CONFIG_TUN) += tun.o
+obj-$(CONFIG_TUN) += tun-drv.o
+tun-drv-y := tun.o tun_vnet.o
 obj-$(CONFIG_TAP) += tap.o
 obj-$(CONFIG_VETH) += veth.o
 obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 1f4a066ad2f0..21abd3613cac 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -83,6 +83,8 @@
 #include <linux/uaccess.h>
 #include <linux/proc_fs.h>
 
+#include "tun_vnet.h"
+
 static void tun_default_link_ksettings(struct net_device *dev,
 				       struct ethtool_link_ksettings *cmd);
 
@@ -94,9 +96,6 @@ static void tun_default_link_ksettings(struct net_device *dev,
  * overload it to mean fasync when stored there.
  */
 #define TUN_FASYNC	IFF_ATTACH_QUEUE
-/* High bits in flags field are unused. */
-#define TUN_VNET_LE     0x80000000
-#define TUN_VNET_BE     0x40000000
 
 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
 		      IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
@@ -298,175 +297,6 @@ static bool tun_napi_frags_enabled(const struct tun_file *tfile)
 	return tfile->napi_frags_enabled;
 }
 
-static inline bool tun_legacy_is_little_endian(unsigned int flags)
-{
-	return !(IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) &&
-		 (flags & TUN_VNET_BE)) &&
-		virtio_legacy_is_little_endian();
-}
-
-static long tun_get_vnet_be(unsigned int flags, int __user *argp)
-{
-	int be = !!(flags & TUN_VNET_BE);
-
-	if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
-		return -EINVAL;
-
-	if (put_user(be, argp))
-		return -EFAULT;
-
-	return 0;
-}
-
-static long tun_set_vnet_be(unsigned int *flags, int __user *argp)
-{
-	int be;
-
-	if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
-		return -EINVAL;
-
-	if (get_user(be, argp))
-		return -EFAULT;
-
-	if (be)
-		*flags |= TUN_VNET_BE;
-	else
-		*flags &= ~TUN_VNET_BE;
-
-	return 0;
-}
-
-static inline bool tun_is_little_endian(unsigned int flags)
-{
-	return flags & TUN_VNET_LE || tun_legacy_is_little_endian(flags);
-}
-
-static inline u16 tun16_to_cpu(unsigned int flags, __virtio16 val)
-{
-	return __virtio16_to_cpu(tun_is_little_endian(flags), val);
-}
-
-static inline __virtio16 cpu_to_tun16(unsigned int flags, u16 val)
-{
-	return __cpu_to_virtio16(tun_is_little_endian(flags), val);
-}
-
-static long tun_vnet_ioctl(int *sz, unsigned int *flags,
-			   unsigned int cmd, int __user *sp)
-{
-	int s;
-
-	switch (cmd) {
-	case TUNGETVNETHDRSZ:
-		s = *sz;
-		if (put_user(s, sp))
-			return -EFAULT;
-		return 0;
-
-	case TUNSETVNETHDRSZ:
-		if (get_user(s, sp))
-			return -EFAULT;
-		if (s < (int)sizeof(struct virtio_net_hdr))
-			return -EINVAL;
-
-		*sz = s;
-		return 0;
-
-	case TUNGETVNETLE:
-		s = !!(*flags & TUN_VNET_LE);
-		if (put_user(s, sp))
-			return -EFAULT;
-		return 0;
-
-	case TUNSETVNETLE:
-		if (get_user(s, sp))
-			return -EFAULT;
-		if (s)
-			*flags |= TUN_VNET_LE;
-		else
-			*flags &= ~TUN_VNET_LE;
-		return 0;
-
-	case TUNGETVNETBE:
-		return tun_get_vnet_be(*flags, sp);
-
-	case TUNSETVNETBE:
-		return tun_set_vnet_be(flags, sp);
-
-	default:
-		return -EINVAL;
-	}
-}
-
-static int tun_vnet_hdr_get(int sz, unsigned int flags, struct iov_iter *from,
-			    struct virtio_net_hdr *hdr)
-{
-	if (iov_iter_count(from) < sz)
-		return -EINVAL;
-
-	if (!copy_from_iter_full(hdr, sizeof(*hdr), from))
-		return -EFAULT;
-
-	if ((hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
-	    tun16_to_cpu(flags, hdr->csum_start) + tun16_to_cpu(flags, hdr->csum_offset) + 2 > tun16_to_cpu(flags, hdr->hdr_len))
-		hdr->hdr_len = cpu_to_tun16(flags, tun16_to_cpu(flags, hdr->csum_start) + tun16_to_cpu(flags, hdr->csum_offset) + 2);
-
-	if (tun16_to_cpu(flags, hdr->hdr_len) > iov_iter_count(from))
-		return -EINVAL;
-
-	iov_iter_advance(from, sz - sizeof(*hdr));
-
-	return tun16_to_cpu(flags, hdr->hdr_len);
-}
-
-static int tun_vnet_hdr_put(int sz, struct iov_iter *iter,
-			    const struct virtio_net_hdr *hdr)
-{
-	if (unlikely(iov_iter_count(iter) < sz))
-		return -EINVAL;
-
-	if (unlikely(copy_to_iter(hdr, sizeof(*hdr), iter) != sizeof(*hdr)))
-		return -EFAULT;
-
-	iov_iter_advance(iter, sz - sizeof(*hdr));
-
-	return 0;
-}
-
-static int tun_vnet_hdr_to_skb(unsigned int flags, struct sk_buff *skb,
-			       const struct virtio_net_hdr *hdr)
-{
-	return virtio_net_hdr_to_skb(skb, hdr, tun_is_little_endian(flags));
-}
-
-static int tun_vnet_hdr_from_skb(unsigned int flags,
-				 const struct net_device *dev,
-				 const struct sk_buff *skb,
-				 struct virtio_net_hdr *hdr)
-{
-	int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0;
-
-	if (virtio_net_hdr_from_skb(skb, hdr,
-				    tun_is_little_endian(flags), true,
-				    vlan_hlen)) {
-		struct skb_shared_info *sinfo = skb_shinfo(skb);
-
-		if (net_ratelimit()) {
-			netdev_err(dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
-				   sinfo->gso_type, tun16_to_cpu(flags, hdr->gso_size),
-				   tun16_to_cpu(flags, hdr->hdr_len));
-			print_hex_dump(KERN_ERR, "tun: ",
-				       DUMP_PREFIX_NONE,
-				       16, 1, skb->head,
-				       min(tun16_to_cpu(flags, hdr->hdr_len), 64), true);
-		}
-		WARN_ON_ONCE(1);
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
 static inline u32 tun_hashfn(u32 rxhash)
 {
 	return rxhash & TUN_MASK_FLOW_ENTRIES;
diff --git a/drivers/net/tun_vnet.c b/drivers/net/tun_vnet.c
new file mode 100644
index 000000000000..5a6cbfb6eed0
--- /dev/null
+++ b/drivers/net/tun_vnet.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include "tun_vnet.h"
+
+/* High bits in flags field are unused. */
+#define TUN_VNET_LE     0x80000000
+#define TUN_VNET_BE     0x40000000
+
+static inline bool tun_legacy_is_little_endian(unsigned int flags)
+{
+	return !(IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) &&
+		 (flags & TUN_VNET_BE)) &&
+		virtio_legacy_is_little_endian();
+}
+
+static long tun_get_vnet_be(unsigned int flags, int __user *argp)
+{
+	int be = !!(flags & TUN_VNET_BE);
+
+	if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
+		return -EINVAL;
+
+	if (put_user(be, argp))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long tun_set_vnet_be(unsigned int *flags, int __user *argp)
+{
+	int be;
+
+	if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
+		return -EINVAL;
+
+	if (get_user(be, argp))
+		return -EFAULT;
+
+	if (be)
+		*flags |= TUN_VNET_BE;
+	else
+		*flags &= ~TUN_VNET_BE;
+
+	return 0;
+}
+
+static inline bool tun_is_little_endian(unsigned int flags)
+{
+	return flags & TUN_VNET_LE || tun_legacy_is_little_endian(flags);
+}
+
+static inline u16 tun16_to_cpu(unsigned int flags, __virtio16 val)
+{
+	return __virtio16_to_cpu(tun_is_little_endian(flags), val);
+}
+
+static inline __virtio16 cpu_to_tun16(unsigned int flags, u16 val)
+{
+	return __cpu_to_virtio16(tun_is_little_endian(flags), val);
+}
+
+long tun_vnet_ioctl(int *sz, unsigned int *flags,
+		    unsigned int cmd, int __user *sp)
+{
+	int s;
+
+	switch (cmd) {
+	case TUNGETVNETHDRSZ:
+		s = *sz;
+		if (put_user(s, sp))
+			return -EFAULT;
+		return 0;
+
+	case TUNSETVNETHDRSZ:
+		if (get_user(s, sp))
+			return -EFAULT;
+		if (s < (int)sizeof(struct virtio_net_hdr))
+			return -EINVAL;
+
+		*sz = s;
+		return 0;
+
+	case TUNGETVNETLE:
+		s = !!(*flags & TUN_VNET_LE);
+		if (put_user(s, sp))
+			return -EFAULT;
+		return 0;
+
+	case TUNSETVNETLE:
+		if (get_user(s, sp))
+			return -EFAULT;
+		if (s)
+			*flags |= TUN_VNET_LE;
+		else
+			*flags &= ~TUN_VNET_LE;
+		return 0;
+
+	case TUNGETVNETBE:
+		return tun_get_vnet_be(*flags, sp);
+
+	case TUNSETVNETBE:
+		return tun_set_vnet_be(flags, sp);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+int tun_vnet_hdr_get(int sz, unsigned int flags, struct iov_iter *from,
+		     struct virtio_net_hdr *hdr)
+{
+	if (iov_iter_count(from) < sz)
+		return -EINVAL;
+
+	if (!copy_from_iter_full(hdr, sizeof(*hdr), from))
+		return -EFAULT;
+
+	if ((hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
+	    tun16_to_cpu(flags, hdr->csum_start) + tun16_to_cpu(flags, hdr->csum_offset) + 2 > tun16_to_cpu(flags, hdr->hdr_len))
+		hdr->hdr_len = cpu_to_tun16(flags, tun16_to_cpu(flags, hdr->csum_start) + tun16_to_cpu(flags, hdr->csum_offset) + 2);
+
+	if (tun16_to_cpu(flags, hdr->hdr_len) > iov_iter_count(from))
+		return -EINVAL;
+
+	iov_iter_advance(from, sz - sizeof(*hdr));
+
+	return tun16_to_cpu(flags, hdr->hdr_len);
+}
+
+int tun_vnet_hdr_put(int sz, struct iov_iter *iter,
+		     const struct virtio_net_hdr *hdr)
+{
+	if (unlikely(iov_iter_count(iter) < sz))
+		return -EINVAL;
+
+	if (unlikely(copy_to_iter(hdr, sizeof(*hdr), iter) != sizeof(*hdr)))
+		return -EFAULT;
+
+	iov_iter_advance(iter, sz - sizeof(*hdr));
+
+	return 0;
+}
+
+int tun_vnet_hdr_to_skb(unsigned int flags, struct sk_buff *skb,
+			const struct virtio_net_hdr *hdr)
+{
+	return virtio_net_hdr_to_skb(skb, hdr, tun_is_little_endian(flags));
+}
+
+int tun_vnet_hdr_from_skb(unsigned int flags,
+			  const struct net_device *dev,
+			  const struct sk_buff *skb,
+			  struct virtio_net_hdr *hdr)
+{
+	int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0;
+
+	if (virtio_net_hdr_from_skb(skb, hdr,
+				    tun_is_little_endian(flags), true,
+				    vlan_hlen)) {
+		struct skb_shared_info *sinfo = skb_shinfo(skb);
+
+		if (net_ratelimit()) {
+			netdev_err(dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
+				   sinfo->gso_type, tun16_to_cpu(flags, hdr->gso_size),
+				   tun16_to_cpu(flags, hdr->hdr_len));
+			print_hex_dump(KERN_ERR, "tun: ",
+				       DUMP_PREFIX_NONE,
+				       16, 1, skb->head,
+				       min(tun16_to_cpu(flags, hdr->hdr_len), 64), true);
+		}
+		WARN_ON_ONCE(1);
+		return -EINVAL;
+	}
+
+	return 0;
+}
diff --git a/drivers/net/tun_vnet.h b/drivers/net/tun_vnet.h
new file mode 100644
index 000000000000..a8d6e4749333
--- /dev/null
+++ b/drivers/net/tun_vnet.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef TUN_VNET_H
+#define TUN_VNET_H
+
+#include <linux/if_tun.h>
+#include <linux/virtio_net.h>
+
+long tun_vnet_ioctl(int *sz, unsigned int *flags,
+		    unsigned int cmd, int __user *sp);
+
+int tun_vnet_hdr_get(int sz, unsigned int flags, struct iov_iter *from,
+		     struct virtio_net_hdr *hdr);
+
+int tun_vnet_hdr_put(int sz, struct iov_iter *iter,
+		     const struct virtio_net_hdr *hdr);
+
+int tun_vnet_hdr_to_skb(unsigned int flags, struct sk_buff *skb,
+			const struct virtio_net_hdr *hdr);
+
+int tun_vnet_hdr_from_skb(unsigned int flags,
+			  const struct net_device *dev,
+			  const struct sk_buff *skb,
+			  struct virtio_net_hdr *hdr);
+
+#endif /* TUN_VNET_H */

-- 
2.47.1