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Date: Thu, 18 Feb 2010 16:48:17 +0100
From: Arnd Bergmann <arnd@...db.de>
To: David Miller <davem@...emloft.net>
Cc: sri@...ibm.com, kaber@...sh.net, eswierk@...stanetworks.com,
netdev@...r.kernel.org
Subject: [PATCH 3/3] macvtap: add GSO/csum offload support
Added flags field to macvtap_queue to enable/disable processing of
virtio_net_hdr via IFF_VNET_HDR. This flag is checked to prepend virtio_net_hdr
in the receive path and process/skip virtio_net_hdr in the send path.
Original patch by Sridhar, further changes by Arnd.
Signed-off-by: Sridhar Samudrala <sri@...ibm.com>
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
drivers/net/macvtap.c | 206 +++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 182 insertions(+), 24 deletions(-)
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index e354501..55ceae0 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -17,6 +17,7 @@
#include <net/net_namespace.h>
#include <net/rtnetlink.h>
#include <net/sock.h>
+#include <linux/virtio_net.h>
/*
* A macvtap queue is the central object of this driver, it connects
@@ -37,6 +38,7 @@ struct macvtap_queue {
struct socket sock;
struct macvlan_dev *vlan;
struct file *file;
+ unsigned int flags;
};
static struct proto macvtap_proto = {
@@ -276,6 +278,7 @@ static int macvtap_open(struct inode *inode, struct file *file)
q->sock.ops = &macvtap_socket_ops;
sock_init_data(&q->sock, &q->sk);
q->sk.sk_write_space = macvtap_sock_write_space;
+ q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
err = macvtap_set_queue(dev, file, q);
if (err)
@@ -318,6 +321,111 @@ out:
return mask;
}
+static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
+ size_t len, size_t linear,
+ int noblock, int *err)
+{
+ struct sk_buff *skb;
+
+ /* Under a page? Don't bother with paged skb. */
+ if (prepad + len < PAGE_SIZE || !linear)
+ linear = len;
+
+ skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
+ err);
+ if (!skb)
+ return NULL;
+
+ skb_reserve(skb, prepad);
+ skb_put(skb, linear);
+ skb->data_len = len - linear;
+ skb->len += len - linear;
+
+ return skb;
+}
+
+/*
+ * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should
+ * be shared with the tun/tap driver.
+ */
+static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb,
+ struct virtio_net_hdr *vnet_hdr)
+{
+ unsigned short gso_type = 0;
+ if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+ switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+ case VIRTIO_NET_HDR_GSO_TCPV4:
+ gso_type = SKB_GSO_TCPV4;
+ break;
+ case VIRTIO_NET_HDR_GSO_TCPV6:
+ gso_type = SKB_GSO_TCPV6;
+ break;
+ case VIRTIO_NET_HDR_GSO_UDP:
+ gso_type = SKB_GSO_UDP;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
+ gso_type |= SKB_GSO_TCP_ECN;
+
+ if (vnet_hdr->gso_size == 0)
+ return -EINVAL;
+ }
+
+ if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+ if (!skb_partial_csum_set(skb, vnet_hdr->csum_start,
+ vnet_hdr->csum_offset))
+ return -EINVAL;
+ }
+
+ if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+ skb_shinfo(skb)->gso_size = vnet_hdr->gso_size;
+ skb_shinfo(skb)->gso_type = gso_type;
+
+ /* Header must be checked, and gso_segs computed. */
+ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+ skb_shinfo(skb)->gso_segs = 0;
+ }
+ return 0;
+}
+
+static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,
+ struct virtio_net_hdr *vnet_hdr)
+{
+ memset(vnet_hdr, 0, sizeof(*vnet_hdr));
+
+ if (skb_is_gso(skb)) {
+ struct skb_shared_info *sinfo = skb_shinfo(skb);
+
+ /* This is a hint as to how much should be linear. */
+ vnet_hdr->hdr_len = skb_headlen(skb);
+ vnet_hdr->gso_size = sinfo->gso_size;
+ if (sinfo->gso_type & SKB_GSO_TCPV4)
+ vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+ else if (sinfo->gso_type & SKB_GSO_TCPV6)
+ vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+ else if (sinfo->gso_type & SKB_GSO_UDP)
+ vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
+ else
+ BUG();
+ if (sinfo->gso_type & SKB_GSO_TCP_ECN)
+ vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+ } else
+ vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+ vnet_hdr->csum_start = skb->csum_start -
+ skb_headroom(skb);
+ vnet_hdr->csum_offset = skb->csum_offset;
+ } /* else everything is zero */
+
+ return 0;
+}
+
+
/* Get packet from user space buffer */
static ssize_t macvtap_get_user(struct macvtap_queue *q,
const struct iovec *iv, size_t count,
@@ -327,22 +435,53 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q,
struct macvlan_dev *vlan;
size_t len = count;
int err;
+ struct virtio_net_hdr vnet_hdr = { 0 };
+ int vnet_hdr_len = 0;
+
+ if (q->flags & IFF_VNET_HDR) {
+ vnet_hdr_len = sizeof(vnet_hdr);
+
+ err = -EINVAL;
+ if ((len -= vnet_hdr_len) < 0)
+ goto err;
+
+ err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
+ vnet_hdr_len);
+ if (err < 0)
+ goto err;
+ if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
+ vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
+ vnet_hdr.hdr_len)
+ vnet_hdr.hdr_len = vnet_hdr.csum_start +
+ vnet_hdr.csum_offset + 2;
+ err = -EINVAL;
+ if (vnet_hdr.hdr_len > len)
+ goto err;
+ }
+ err = -EINVAL;
if (unlikely(len < ETH_HLEN))
- return -EINVAL;
+ goto err;
- skb = sock_alloc_send_skb(&q->sk, NET_IP_ALIGN + len, noblock, &err);
+ skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, len, vnet_hdr.hdr_len,
+ noblock, &err);
if (!skb)
goto err;
- skb_reserve(skb, NET_IP_ALIGN);
- skb_put(skb, count);
-
- err = skb_copy_datagram_from_iovec(skb, 0, iv, 0, len);
+ err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, len);
if (err)
- goto err;
+ goto err_kfree;
skb_set_network_header(skb, ETH_HLEN);
+ skb_reset_mac_header(skb);
+ skb->protocol = eth_hdr(skb)->h_proto;
+
+ if (vnet_hdr_len) {
+ err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr);
+ if (err)
+ goto err_kfree;
+ }
+
rcu_read_lock_bh();
vlan = rcu_dereference(q->vlan);
if (vlan)
@@ -353,15 +492,16 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q,
return count;
+err_kfree:
+ kfree_skb(skb);
+
err:
rcu_read_lock_bh();
vlan = rcu_dereference(q->vlan);
if (vlan)
- macvlan_count_rx(q->vlan, 0, false, false);
+ netdev_get_tx_queue(vlan->dev, 0)->tx_dropped++;
rcu_read_unlock_bh();
- kfree_skb(skb);
-
return err;
}
@@ -384,10 +524,25 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
{
struct macvlan_dev *vlan;
int ret;
+ int vnet_hdr_len = 0;
+
+ if (q->flags & IFF_VNET_HDR) {
+ struct virtio_net_hdr vnet_hdr;
+ vnet_hdr_len = sizeof (vnet_hdr);
+ if ((len -= vnet_hdr_len) < 0)
+ return -EINVAL;
+
+ ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr);
+ if (ret)
+ return ret;
+
+ if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, vnet_hdr_len))
+ return -EFAULT;
+ }
len = min_t(int, skb->len, len);
- ret = skb_copy_datagram_const_iovec(skb, 0, iv, 0, len);
+ ret = skb_copy_datagram_const_iovec(skb, 0, iv, vnet_hdr_len, len);
rcu_read_lock_bh();
vlan = rcu_dereference(q->vlan);
@@ -395,7 +550,7 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
macvlan_count_rx(vlan, len, ret == 0, 0);
rcu_read_unlock_bh();
- return ret ? ret : len;
+ return ret ? ret : (len + vnet_hdr_len);
}
static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
@@ -473,9 +628,14 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd,
/* ignore the name, just look at flags */
if (get_user(u, &ifr->ifr_flags))
return -EFAULT;
- if (u != (IFF_TAP | IFF_NO_PI))
- return -EINVAL;
- return 0;
+
+ ret = 0;
+ if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))
+ ret = -EINVAL;
+ else
+ q->flags = u;
+
+ return ret;
case TUNGETIFF:
rcu_read_lock_bh();
@@ -489,13 +649,13 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd,
ret = 0;
if (copy_to_user(&ifr->ifr_name, q->vlan->dev->name, IFNAMSIZ) ||
- put_user((TUN_TAP_DEV | TUN_NO_PI), &ifr->ifr_flags))
+ put_user(q->flags, &ifr->ifr_flags))
ret = -EFAULT;
dev_put(vlan->dev);
return ret;
case TUNGETFEATURES:
- if (put_user((IFF_TAP | IFF_NO_PI), up))
+ if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up))
return -EFAULT;
return 0;
@@ -509,15 +669,13 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd,
case TUNSETOFFLOAD:
/* let the user check for future flags */
if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
- TUN_F_TSO_ECN | TUN_F_UFO))
- return -EINVAL;
-
- /* TODO: add support for these, so far we don't
- support any offload */
- if (arg & (TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
- TUN_F_TSO_ECN | TUN_F_UFO))
+ TUN_F_TSO_ECN | TUN_F_UFO))
return -EINVAL;
+ /* TODO: only accept frames with the features that
+ got enabled for forwarded frames */
+ if (!(q->flags & IFF_VNET_HDR))
+ return -EINVAL;
return 0;
default:
--
1.6.3.3
--
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