Commit bfd5f4a3 authored by Sridhar Samudrala's avatar Sridhar Samudrala Committed by David S. Miller
Browse files

packet: Add GSO/csum offload support. 



This patch adds GSO/checksum offload to af_packet sockets using
virtio_net_hdr. Based on Rusty's patch to add this support to tun.
It allows GSO/checksum offload to be enabled when using raw socket
backend with virtio_net.
Adds PACKET_VNET_HDR socket option to prepend virtio_net_hdr in the
receive path and process/skip virtio_net_hdr in the send path. This
option is only allowed with SOCK_RAW sockets attached to ethernet
type devices.

v2 updates
----------
Michael's Comments
- Perform length check in packet_snd() when GSO is off even when
  vnet_hdr is present.
- Check for SKB_GSO_FCOE type and return -EINVAL
- don't allow tx/rx ring when vnet_hdr is enabled.
Herbert's Comments
- Removed ethernet specific code.
- protocol value is assumed to be passed in by the caller.

Signed-off-by: default avatarSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 746079da

include/linux/if_packet.h

+1 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ struct sockaddr_ll { 
#define PACKET_RESERVE			12

#define PACKET_TX_RING			13

#define PACKET_LOSS			14

#define PACKET_VNET_HDR			15



struct tpacket_stats {

	unsigned int	tp_packets;

net/packet/af_packet.c

+176 −11
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ 
#include <linux/init.h>

#include <linux/mutex.h>

#include <linux/if_vlan.h>

#include <linux/virtio_net.h>



#ifdef CONFIG_INET

#include <net/inet_common.h>
@@ -193,7 +194,8 @@ struct packet_sock { 
	struct mutex		pg_vec_lock;

	unsigned int		running:1,	/* prot_hook is attached*/

				auxdata:1,

				origdev:1;

				origdev:1,

				has_vnet_hdr:1;

	int			ifindex;	/* bound device		*/

	__be16			num;

	struct packet_mclist	*mclist;
@@ -1056,6 +1058,30 @@ out: 
}

#endif



static inline struct sk_buff *packet_alloc_skb(struct sock *sk, size_t prepad,

					       size_t reserve, 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, reserve);

	skb_put(skb, linear);

	skb->data_len = len - linear;

	skb->len += len - linear;



	return skb;

}



static int packet_snd(struct socket *sock,

			  struct msghdr *msg, size_t len)

{
@@ -1066,14 +1092,17 @@ static int packet_snd(struct socket *sock, 
	__be16 proto;

	unsigned char *addr;

	int ifindex, err, reserve = 0;

	struct virtio_net_hdr vnet_hdr = { 0 };

	int offset = 0;

	int vnet_hdr_len;

	struct packet_sock *po = pkt_sk(sk);

	unsigned short gso_type = 0;



	/*

	 *	Get and verify the address.

	 */



	if (saddr == NULL) {

		struct packet_sock *po = pkt_sk(sk);



		ifindex	= po->ifindex;

		proto	= po->num;

		addr	= NULL;
@@ -1100,25 +1129,74 @@ static int packet_snd(struct socket *sock, 
	if (!(dev->flags & IFF_UP))

		goto out_unlock;



	if (po->has_vnet_hdr) {

		vnet_hdr_len = sizeof(vnet_hdr);



		err = -EINVAL;

		if (len < vnet_hdr_len)

			goto out_unlock;



		len -= vnet_hdr_len;



		err = memcpy_fromiovec((void *)&vnet_hdr, msg->msg_iov,

				       vnet_hdr_len);

		if (err < 0)

			goto out_unlock;



		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 out_unlock;



		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:

				goto out_unlock;

			}



			if (vnet_hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)

				gso_type |= SKB_GSO_TCP_ECN;



			if (vnet_hdr.gso_size == 0)

				goto out_unlock;



		}

	}



	err = -EMSGSIZE;

	if (len > dev->mtu+reserve)

	if (!gso_type && (len > dev->mtu+reserve))

		goto out_unlock;



	skb = sock_alloc_send_skb(sk, len + LL_ALLOCATED_SPACE(dev),

	err = -ENOBUFS;

	skb = packet_alloc_skb(sk, LL_ALLOCATED_SPACE(dev),

			       LL_RESERVED_SPACE(dev), len, vnet_hdr.hdr_len,

			       msg->msg_flags & MSG_DONTWAIT, &err);

	if (skb == NULL)

		goto out_unlock;



	skb_reserve(skb, LL_RESERVED_SPACE(dev));

	skb_reset_network_header(skb);

	skb_set_network_header(skb, reserve);



	err = -EINVAL;

	if (sock->type == SOCK_DGRAM &&

	    dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len) < 0)

	    (offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len)) < 0)

		goto out_free;



	/* Returns -EFAULT on error */

	err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);

	err = skb_copy_datagram_from_iovec(skb, offset, msg->msg_iov, 0, len);

	if (err)

		goto out_free;
@@ -1127,6 +1205,25 @@ static int packet_snd(struct socket *sock, 
	skb->priority = sk->sk_priority;

	skb->mark = sk->sk_mark;



	if (po->has_vnet_hdr) {

		if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {

			if (!skb_partial_csum_set(skb, vnet_hdr.csum_start,

						  vnet_hdr.csum_offset)) {

				err = -EINVAL;

				goto out_free;

			}

		}



		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;



		len += vnet_hdr_len;

	}



	/*

	 *	Now send it

	 */
@@ -1420,6 +1517,7 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, 
	struct sk_buff *skb;

	int copied, err;

	struct sockaddr_ll *sll;

	int vnet_hdr_len = 0;



	err = -EINVAL;

	if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT))
@@ -1451,6 +1549,48 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, 
	if (skb == NULL)

		goto out;



	if (pkt_sk(sk)->has_vnet_hdr) {

		struct virtio_net_hdr vnet_hdr = { 0 };



		err = -EINVAL;

		vnet_hdr_len = sizeof(vnet_hdr);

		if ((len -= vnet_hdr_len) < 0)

			goto out_free;



		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 if (sinfo->gso_type & SKB_GSO_FCOE)

				goto out_free;

			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 */



		err = memcpy_toiovec(msg->msg_iov, (void *)&vnet_hdr,

				     vnet_hdr_len);

		if (err < 0)

			goto out_free;

	}



	/*

	 *	If the address length field is there to be filled in, we fill

	 *	it in now.
@@ -1502,7 +1642,7 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, 
	 *	Free or return the buffer as appropriate. Again this

	 *	hides all the races and re-entrancy issues from us.

	 */

	err = (flags&MSG_TRUNC) ? skb->len : copied;

	err = vnet_hdr_len + ((flags&MSG_TRUNC) ? skb->len : copied);



out_free:

	skb_free_datagram(sk, skb);
@@ -1740,6 +1880,8 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv 


		if (optlen < sizeof(req))

			return -EINVAL;

		if (pkt_sk(sk)->has_vnet_hdr)

			return -EINVAL;

		if (copy_from_user(&req, optval, sizeof(req)))

			return -EFAULT;

		return packet_set_ring(sk, &req, 0, optname == PACKET_TX_RING);
@@ -1826,6 +1968,22 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv 
		po->origdev = !!val;

		return 0;

	}

	case PACKET_VNET_HDR:

	{

		int val;



		if (sock->type != SOCK_RAW)

			return -EINVAL;

		if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)

			return -EBUSY;

		if (optlen < sizeof(val))

			return -EINVAL;

		if (copy_from_user(&val, optval, sizeof(val)))

			return -EFAULT;



		po->has_vnet_hdr = !!val;

		return 0;

	}

	default:

		return -ENOPROTOOPT;

	}
@@ -1874,6 +2032,13 @@ static int packet_getsockopt(struct socket *sock, int level, int optname, 
			len = sizeof(int);

		val = po->origdev;



		data = &val;

		break;

	case PACKET_VNET_HDR:

		if (len > sizeof(int))

			len = sizeof(int);

		val = po->has_vnet_hdr;



		data = &val;

		break;

#ifdef CONFIG_PACKET_MMAP

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