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Commit d3869efe authored by David Woodhouse's avatar David Woodhouse Committed by David S. Miller
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Fix AF_PACKET ABI breakage in 4.2 



Commit 7d824109 ("virtio: add explicit big-endian support to memory
accessors") accidentally changed the virtio_net header used by
AF_PACKET with PACKET_VNET_HDR from host-endian to big-endian.

Since virtio_legacy_is_little_endian() is a very long identifier,
define a vio_le macro and use that throughout the code instead of the
hard-coded 'false' for little-endian.

This restores the ABI to match 4.1 and earlier kernels, and makes my
test program work again.

Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2d8bff12

net/packet/af_packet.c

+17 −15
Original line number Diff line number Diff line
@@ -230,6 +230,8 @@ struct packet_skb_cb { 
	} sa;

};



#define vio_le() virtio_legacy_is_little_endian()



#define PACKET_SKB_CB(__skb)	((struct packet_skb_cb *)((__skb)->cb))



#define GET_PBDQC_FROM_RB(x)	((struct tpacket_kbdq_core *)(&(x)->prb_bdqc))
@@ -2680,15 +2682,15 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 
			goto out_unlock;



		if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&

		    (__virtio16_to_cpu(false, vnet_hdr.csum_start) +

		     __virtio16_to_cpu(false, vnet_hdr.csum_offset) + 2 >

		      __virtio16_to_cpu(false, vnet_hdr.hdr_len)))

			vnet_hdr.hdr_len = __cpu_to_virtio16(false,

				 __virtio16_to_cpu(false, vnet_hdr.csum_start) +

				__virtio16_to_cpu(false, vnet_hdr.csum_offset) + 2);

		    (__virtio16_to_cpu(vio_le(), vnet_hdr.csum_start) +

		     __virtio16_to_cpu(vio_le(), vnet_hdr.csum_offset) + 2 >

		      __virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len)))

			vnet_hdr.hdr_len = __cpu_to_virtio16(vio_le(),

				 __virtio16_to_cpu(vio_le(), vnet_hdr.csum_start) +

				__virtio16_to_cpu(vio_le(), vnet_hdr.csum_offset) + 2);



		err = -EINVAL;

		if (__virtio16_to_cpu(false, vnet_hdr.hdr_len) > len)

		if (__virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len) > len)

			goto out_unlock;



		if (vnet_hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
@@ -2731,7 +2733,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 
	hlen = LL_RESERVED_SPACE(dev);

	tlen = dev->needed_tailroom;

	skb = packet_alloc_skb(sk, hlen + tlen, hlen, len,

			       __virtio16_to_cpu(false, vnet_hdr.hdr_len),

			       __virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len),

			       msg->msg_flags & MSG_DONTWAIT, &err);

	if (skb == NULL)

		goto out_unlock;
@@ -2778,8 +2780,8 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 


	if (po->has_vnet_hdr) {

		if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {

			u16 s = __virtio16_to_cpu(false, vnet_hdr.csum_start);

			u16 o = __virtio16_to_cpu(false, vnet_hdr.csum_offset);

			u16 s = __virtio16_to_cpu(vio_le(), vnet_hdr.csum_start);

			u16 o = __virtio16_to_cpu(vio_le(), vnet_hdr.csum_offset);

			if (!skb_partial_csum_set(skb, s, o)) {

				err = -EINVAL;

				goto out_free;
@@ -2787,7 +2789,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 
		}



		skb_shinfo(skb)->gso_size =

			__virtio16_to_cpu(false, vnet_hdr.gso_size);

			__virtio16_to_cpu(vio_le(), vnet_hdr.gso_size);

		skb_shinfo(skb)->gso_type = gso_type;



		/* Header must be checked, and gso_segs computed. */
@@ -3161,9 +3163,9 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 


			/* This is a hint as to how much should be linear. */

			vnet_hdr.hdr_len =

				__cpu_to_virtio16(false, skb_headlen(skb));

				__cpu_to_virtio16(vio_le(), skb_headlen(skb));

			vnet_hdr.gso_size =

				__cpu_to_virtio16(false, sinfo->gso_size);

				__cpu_to_virtio16(vio_le(), 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)
@@ -3181,9 +3183,9 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 


		if (skb->ip_summed == CHECKSUM_PARTIAL) {

			vnet_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;

			vnet_hdr.csum_start = __cpu_to_virtio16(false,

			vnet_hdr.csum_start = __cpu_to_virtio16(vio_le(),

					  skb_checksum_start_offset(skb));

			vnet_hdr.csum_offset = __cpu_to_virtio16(false,

			vnet_hdr.csum_offset = __cpu_to_virtio16(vio_le(),

							 skb->csum_offset);

		} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {

			vnet_hdr.flags = VIRTIO_NET_HDR_F_DATA_VALID;