tun: Allow GSO using virtio_net_hdr
Add a IFF_VNET_HDR flag. This uses the same ABI as virtio_net
(ie. prepending struct virtio_net_hdr to packets) to indicate GSO and
checksum information.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Max Krasnyansky <maxk@qualcomm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index a314955..aa4ee44 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -63,6 +63,7 @@
#include <linux/if_tun.h>
#include <linux/crc32.h>
#include <linux/nsproxy.h>
+#include <linux/virtio_net.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
@@ -283,6 +284,7 @@
struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
struct sk_buff *skb;
size_t len = count, align = 0;
+ struct virtio_net_hdr gso = { 0 };
if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) > count)
@@ -292,6 +294,17 @@
return -EFAULT;
}
+ if (tun->flags & TUN_VNET_HDR) {
+ if ((len -= sizeof(gso)) > count)
+ return -EINVAL;
+
+ if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
+ return -EFAULT;
+
+ if (gso.hdr_len > len)
+ return -EINVAL;
+ }
+
if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
align = NET_IP_ALIGN;
if (unlikely(len < ETH_HLEN))
@@ -311,6 +324,16 @@
return -EFAULT;
}
+ if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+ if (!skb_partial_csum_set(skb, gso.csum_start,
+ gso.csum_offset)) {
+ tun->dev->stats.rx_frame_errors++;
+ kfree_skb(skb);
+ return -EINVAL;
+ }
+ } else if (tun->flags & TUN_NOCHECKSUM)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
switch (tun->flags & TUN_TYPE_MASK) {
case TUN_TUN_DEV:
if (tun->flags & TUN_NO_PI) {
@@ -337,8 +360,35 @@
break;
};
- if (tun->flags & TUN_NOCHECKSUM)
- skb->ip_summed = CHECKSUM_UNNECESSARY;
+ if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+ pr_debug("GSO!\n");
+ switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+ case VIRTIO_NET_HDR_GSO_TCPV4:
+ skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+ break;
+ case VIRTIO_NET_HDR_GSO_TCPV6:
+ skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+ break;
+ default:
+ tun->dev->stats.rx_frame_errors++;
+ kfree_skb(skb);
+ return -EINVAL;
+ }
+
+ if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
+ skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
+
+ skb_shinfo(skb)->gso_size = gso.gso_size;
+ if (skb_shinfo(skb)->gso_size == 0) {
+ tun->dev->stats.rx_frame_errors++;
+ kfree_skb(skb);
+ return -EINVAL;
+ }
+
+ /* Header must be checked, and gso_segs computed. */
+ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+ skb_shinfo(skb)->gso_segs = 0;
+ }
netif_rx_ni(skb);
tun->dev->last_rx = jiffies;
@@ -384,6 +434,39 @@
total += sizeof(pi);
}
+ if (tun->flags & TUN_VNET_HDR) {
+ struct virtio_net_hdr gso = { 0 }; /* no info leak */
+ if ((len -= sizeof(gso)) < 0)
+ return -EINVAL;
+
+ if (skb_is_gso(skb)) {
+ struct skb_shared_info *sinfo = skb_shinfo(skb);
+
+ /* This is a hint as to how much should be linear. */
+ gso.hdr_len = skb_headlen(skb);
+ gso.gso_size = sinfo->gso_size;
+ if (sinfo->gso_type & SKB_GSO_TCPV4)
+ gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+ else if (sinfo->gso_type & SKB_GSO_TCPV6)
+ gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+ else
+ BUG();
+ if (sinfo->gso_type & SKB_GSO_TCP_ECN)
+ gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+ } else
+ gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+ gso.csum_start = skb->csum_start - skb_headroom(skb);
+ gso.csum_offset = skb->csum_offset;
+ } /* else everything is zero */
+
+ if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
+ return -EFAULT;
+ total += sizeof(gso);
+ }
+
len = min_t(int, skb->len, len);
skb_copy_datagram_iovec(skb, 0, iv, len);
@@ -598,6 +681,11 @@
else
tun->flags &= ~TUN_ONE_QUEUE;
+ if (ifr->ifr_flags & IFF_VNET_HDR)
+ tun->flags |= TUN_VNET_HDR;
+ else
+ tun->flags &= ~TUN_VNET_HDR;
+
file->private_data = tun;
tun->attached = 1;
get_net(dev_net(tun->dev));
@@ -684,7 +772,8 @@
/* Currently this just means: "what IFF flags are valid?".
* This is needed because we never checked for invalid flags on
* TUNSETIFF. */
- return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE,
+ return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
+ IFF_VNET_HDR,
(unsigned int __user*)argp);
}
diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h
index 3f0a099..563fae5 100644
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -31,6 +31,7 @@
#define TUN_NO_PI 0x0040
#define TUN_ONE_QUEUE 0x0080
#define TUN_PERSIST 0x0100
+#define TUN_VNET_HDR 0x0200
/* Ioctl defines */
#define TUNSETNOCSUM _IOW('T', 200, int)
@@ -48,6 +49,7 @@
#define IFF_TAP 0x0002
#define IFF_NO_PI 0x1000
#define IFF_ONE_QUEUE 0x2000
+#define IFF_VNET_HDR 0x4000
/* Features for GSO (TUNSETOFFLOAD). */
#define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */