[PATCH net-next 5/7] vxlan: clean up extension handling on rx

[Jiri Benc]

Bring the extension handling to a single place and move the actual handling
logic out of vxlan_udp_encap_recv as much as possible.

Signed-off-by: Jiri Benc <jb...@redhat.com>
---
 drivers/net/vxlan.c | 62 +++++++++++++++++++++++++++--------------------------
 1 file changed, 32 insertions(+), 30 deletions(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 45467552162a..40f61c15a4a6 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1125,15 +1125,16 @@ static int vxlan_igmp_leave(struct vxlan_dev *vxlan)
        return ret;
 }
 
-static bool vxlan_remcsum(struct sk_buff *skb, u32 vxflags, __be32 vni_field)
+static bool vxlan_remcsum(struct vxlanhdr *unparsed,
+                         struct sk_buff *skb, u32 vxflags)
 {
        size_t start, offset, plen;
 
-       if (skb->remcsum_offload)
-               return true;
+       if (!(unparsed->vx_flags & VXLAN_HF_RCO) || skb->remcsum_offload)
+               goto out;
 
-       start = vxlan_rco_start(vni_field);
-       offset = start + vxlan_rco_offset(vni_field);
+       start = vxlan_rco_start(unparsed->vx_vni);
+       offset = start + vxlan_rco_offset(unparsed->vx_vni);
 
        plen = sizeof(struct vxlanhdr) + offset + sizeof(u16);
 
@@ -1142,16 +1143,21 @@ static bool vxlan_remcsum(struct sk_buff *skb, u32 
vxflags, __be32 vni_field)
 
        skb_remcsum_process(skb, (void *)(vxlan_hdr(skb) + 1), start, offset,
                            !!(vxflags & VXLAN_F_REMCSUM_NOPARTIAL));
-
+out:
+       unparsed->vx_flags &= ~VXLAN_HF_RCO;
+       unparsed->vx_vni &= VXLAN_VNI_MASK;
        return true;
 }
 
-static void vxlan_parse_gbp_hdr(struct sk_buff *skb, struct vxlan_metadata *md,
+static void vxlan_parse_gbp_hdr(struct vxlanhdr *unparsed,
+                               struct vxlan_metadata *md,
                                struct metadata_dst *tun_dst)
 {
-       struct vxlanhdr_gbp *gbp;
+       struct vxlanhdr_gbp *gbp = (struct vxlanhdr_gbp *)unparsed;
+
+       if (!(unparsed->vx_flags & VXLAN_HF_GBP))
+               goto out;
 
-       gbp = (struct vxlanhdr_gbp *)vxlan_hdr(skb);
        md->gbp = ntohs(gbp->policy_id);
 
        if (tun_dst)
@@ -1162,6 +1168,9 @@ static void vxlan_parse_gbp_hdr(struct sk_buff *skb, 
struct vxlan_metadata *md,
 
        if (gbp->policy_applied)
                md->gbp |= VXLAN_GBP_POLICY_APPLIED;
+
+out:
+       unparsed->vx_flags &= ~VXLAN_GBP_USED_BITS;
 }
 
 static void vxlan_rcv(struct vxlan_sock *vs, struct sk_buff *skb,
@@ -1263,7 +1272,7 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct 
sk_buff *skb)
 {
        struct metadata_dst *tun_dst = NULL;
        struct vxlan_sock *vs;
-       __be32 flags, vni_field;
+       struct vxlanhdr unparsed;
        struct vxlan_metadata _md;
        struct vxlan_metadata *md = &_md;
 
@@ -1271,11 +1280,10 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct 
sk_buff *skb)
        if (!pskb_may_pull(skb, VXLAN_HLEN))
                goto error;
 
-       flags = vxlan_hdr(skb)->vx_flags;
-       vni_field = vxlan_hdr(skb)->vx_vni;
-
-       if (flags & VXLAN_HF_VNI) {
-               flags &= ~VXLAN_HF_VNI;
+       unparsed = *vxlan_hdr(skb);
+       if (unparsed.vx_flags & VXLAN_HF_VNI) {
+               unparsed.vx_flags &= ~VXLAN_HF_VNI;
+               unparsed.vx_vni &= ~VXLAN_VNI_MASK;
        } else {
                /* VNI flag always required to be set */
                goto bad_flags;
@@ -1288,17 +1296,10 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct 
sk_buff *skb)
        if (!vs)
                goto drop;
 
-       if ((flags & VXLAN_HF_RCO) && (vs->flags & VXLAN_F_REMCSUM_RX)) {
-               if (!vxlan_remcsum(skb, vs->flags, vni_field))
-                       goto drop;
-
-               flags &= ~VXLAN_HF_RCO;
-               vni_field &= VXLAN_VNI_MASK;
-       }
-
        if (vxlan_collect_metadata(vs)) {
                tun_dst = udp_tun_rx_dst(skb, vxlan_get_sk_family(vs), 
TUNNEL_KEY,
-                                        vxlan_vni(vni_field), sizeof(*md));
+                                        vxlan_vni(vxlan_hdr(skb)->vx_vni),
+                                        sizeof(*md));
 
                if (!tun_dst)
                        goto drop;
@@ -1311,12 +1312,13 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct 
sk_buff *skb)
        /* For backwards compatibility, only allow reserved fields to be
         * used by VXLAN extensions if explicitly requested.
         */
-       if ((flags & VXLAN_HF_GBP) && (vs->flags & VXLAN_F_GBP)) {
-               vxlan_parse_gbp_hdr(skb, md, tun_dst);
-               flags &= ~VXLAN_GBP_USED_BITS;
-       }
+       if (vs->flags & VXLAN_F_REMCSUM_RX)
+               if (!vxlan_remcsum(&unparsed, skb, vs->flags))
+                       goto drop;
+       if (vs->flags & VXLAN_F_GBP)
+               vxlan_parse_gbp_hdr(&unparsed, md, tun_dst);
 
-       if (flags || vni_field & ~VXLAN_VNI_MASK) {
+       if (unparsed.vx_flags || unparsed.vx_vni) {
                /* 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
@@ -1329,7 +1331,7 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct 
sk_buff *skb)
                goto bad_flags;
        }
 
-       vxlan_rcv(vs, skb, md, vxlan_vni(vni_field), tun_dst);
+       vxlan_rcv(vs, skb, md, vxlan_vni(vxlan_hdr(skb)->vx_vni), tun_dst);
        return 0;
 
 drop:
-- 
1.8.3.1