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Commit 3bf39475 authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

vxlan: Improve support for header flags 



This patch cleans up the header flags of VXLAN in anticipation of
defining some new ones:

- Move header related definitions from vxlan.c to vxlan.h
- Change VXLAN_FLAGS to be VXLAN_HF_VNI (only currently defined flag)
- Move check for unknown flags to after we find vxlan_sock, this
  assumes that some flags may be processed based on tunnel
  configuration
- Add a comment about why the stack treating unknown set flags as an
  error instead of ignoring them

Signed-off-by: default avatarTom Herbert <therbert@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent eee2f04b

drivers/net/vxlan.c

+28 −14
Original line number Diff line number Diff line
@@ -61,12 +61,6 @@ 
#define FDB_AGE_DEFAULT 300 /* 5 min */

#define FDB_AGE_INTERVAL (10 * HZ)	/* rescan interval */



#define VXLAN_N_VID	(1u << 24)

#define VXLAN_VID_MASK	(VXLAN_N_VID - 1)

#define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))



#define VXLAN_FLAGS 0x08000000	/* struct vxlanhdr.vx_flags required value. */



/* UDP port for VXLAN traffic.

 * The IANA assigned port is 4789, but the Linux default is 8472

 * for compatibility with early adopters.
@@ -1095,18 +1089,21 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 
{

	struct vxlan_sock *vs;

	struct vxlanhdr *vxh;

	u32 flags, vni;



	/* Need Vxlan and inner Ethernet header to be present */

	if (!pskb_may_pull(skb, VXLAN_HLEN))

		goto error;



	/* Return packets with reserved bits set */

	vxh = (struct vxlanhdr *)(udp_hdr(skb) + 1);

	if (vxh->vx_flags != htonl(VXLAN_FLAGS) ||

	    (vxh->vx_vni & htonl(0xff))) {

		netdev_dbg(skb->dev, "invalid vxlan flags=%#x vni=%#x\n",

			   ntohl(vxh->vx_flags), ntohl(vxh->vx_vni));

		goto error;

	flags = ntohl(vxh->vx_flags);

	vni = ntohl(vxh->vx_vni);



	if (flags & VXLAN_HF_VNI) {

		flags &= ~VXLAN_HF_VNI;

	} else {

		/* VNI flag always required to be set */

		goto bad_flags;

	}



	if (iptunnel_pull_header(skb, VXLAN_HLEN, htons(ETH_P_TEB)))
@@ -1116,6 +1113,19 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 
	if (!vs)

		goto drop;



	if (flags || (vni & 0xff)) {

		/* If there are any unprocessed flags remaining treat

		 * this as a malformed packet. This behavior diverges from

		 * VXLAN RFC (RFC7348) which stipulates that bits in reserved

		 * in reserved fields are to be ignored. The approach here

		 * maintains compatbility with previous stack code, and also

		 * is more robust and provides a little more security in

		 * adding extensions to VXLAN.

		 */



		goto bad_flags;

	}



	vs->rcv(vs, skb, vxh->vx_vni);

	return 0;
@@ -1124,6 +1134,10 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 
	kfree_skb(skb);

	return 0;



bad_flags:

	netdev_dbg(skb->dev, "invalid vxlan flags=%#x vni=%#x\n",

		   ntohl(vxh->vx_flags), ntohl(vxh->vx_vni));



error:

	/* Return non vxlan pkt */

	return 1;
@@ -1563,7 +1577,7 @@ static int vxlan6_xmit_skb(struct vxlan_sock *vs, 
	}



	vxh = (struct vxlanhdr *) __skb_push(skb, sizeof(*vxh));

	vxh->vx_flags = htonl(VXLAN_FLAGS);

	vxh->vx_flags = htonl(VXLAN_HF_VNI);

	vxh->vx_vni = vni;



	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
@@ -1607,7 +1621,7 @@ int vxlan_xmit_skb(struct vxlan_sock *vs, 
		return -ENOMEM;



	vxh = (struct vxlanhdr *) __skb_push(skb, sizeof(*vxh));

	vxh->vx_flags = htonl(VXLAN_FLAGS);

	vxh->vx_flags = htonl(VXLAN_HF_VNI);

	vxh->vx_vni = vni;



	skb_set_inner_protocol(skb, htons(ETH_P_TEB));

include/net/vxlan.h

+7 −0
Original line number Diff line number Diff line
@@ -17,6 +17,13 @@ struct vxlanhdr { 
	__be32 vx_vni;

};



/* VXLAN header flags. */

#define VXLAN_HF_VNI 0x08000000



#define VXLAN_N_VID     (1u << 24)

#define VXLAN_VID_MASK  (VXLAN_N_VID - 1)

#define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))



struct vxlan_sock;

typedef void (vxlan_rcv_t)(struct vxlan_sock *vh, struct sk_buff *skb, __be32 key);