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vxlan: Improve support for header flags

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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: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert 2015-01-08 12:31:18 -08:00 committed by David S. Miller
parent eee2f04b80
commit 3bf3947526
2 changed files with 35 additions and 14 deletions
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42
drivers/net/vxlan.c
View File

@ -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 @@ drop:
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));

7
include/net/vxlan.h
View File

@ -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);