vxlan: fix wrong usage of VXLAN_VID_MASK (40fb70f3) · Commits · 戴 / test

commit wrongly assumes that VXLAN_VDI_MASK includes eight lower order reserved bits of VNI field that are using for remote checksum offload. Right now, when VNI number greater then 0xffff, vxlan_udp_encap_recv() will always return with 'bad_flag' error, reducing the usable vni range from 0..16777215 to 0..65535. Also, it doesn't really check whether RCO bits processed or not. Fix it by adding new VNI mask which has all 32 bits of VNI field: 24 bits for id and 8 bits for other usage. Signed-off-by:

Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1218,7 +1218,7 @@ static int vxlan_udp_encap_recv(struct sock sk, struct sk_buff skb)
		goto drop;

		flags &= ~VXLAN_HF_RCO;
		vni &= VXLAN_VID_MASK;
		vni &= VXLAN_VNI_MASK;
		}

		/* For backwards compatibility, only allow reserved fields to be
		@@ -1239,7 +1239,7 @@ static int vxlan_udp_encap_recv(struct sock sk, struct sk_buff skb)
		flags &= ~VXLAN_GBP_USED_BITS;
		}

		if (flags \|\| (vni & ~VXLAN_VID_MASK)) {
		if (flags \|\| vni & ~VXLAN_VNI_MASK) {
		/* 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

include/net/vxlan.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -91,6 +91,7 @@ struct vxlanhdr {

		#define VXLAN_N_VID (1u << 24)
		#define VXLAN_VID_MASK (VXLAN_N_VID - 1)
		#define VXLAN_VNI_MASK (VXLAN_VID_MASK << 8)
		#define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))

		struct vxlan_metadata {

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