3 files changed, 198 insertions, 6 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 5c56a3ff25aa..99df0d76157c 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -539,6 +539,46 @@ static int vxlan_fdb_append(struct vxlan_fdb *f,
         return 1;
 }
 
+static struct vxlanhdr *vxlan_gro_remcsum(struct sk_buff *skb,
+                                          unsigned int off,
+                                          struct vxlanhdr *vh, size_t hdrlen,
+                                          u32 data)
+{
+        size_t start, offset, plen;
+        __wsum delta;
+
+        if (skb->remcsum_offload)
+                return vh;
+
+        if (!NAPI_GRO_CB(skb)->csum_valid)
+                return NULL;
+
+        start = (data & VXLAN_RCO_MASK) << VXLAN_RCO_SHIFT;
+        offset = start + ((data & VXLAN_RCO_UDP) ?
+                          offsetof(struct udphdr, check) :
+                          offsetof(struct tcphdr, check));
+
+        plen = hdrlen + offset + sizeof(u16);
+
+        /* Pull checksum that will be written */
+        if (skb_gro_header_hard(skb, off + plen)) {
+                vh = skb_gro_header_slow(skb, off + plen, off);
+                if (!vh)
+                        return NULL;
+        }
+
+        delta = remcsum_adjust((void *)vh + hdrlen,
+                               NAPI_GRO_CB(skb)->csum, start, offset);
+
+        /* Adjust skb->csum since we changed the packet */
+        skb->csum = csum_add(skb->csum, delta);
+        NAPI_GRO_CB(skb)->csum = csum_add(NAPI_GRO_CB(skb)->csum, delta);
+
+        skb->remcsum_offload = 1;
+
+        return vh;
+}
+
 static struct sk_buff **vxlan_gro_receive(struct sk_buff **head,
                                           struct sk_buff *skb,
                                           struct udp_offload *uoff)
@@ -547,6 +587,9 @@ static struct sk_buff **vxlan_gro_receive(struct sk_buff **head,
         struct vxlanhdr *vh, *vh2;
         unsigned int hlen, off_vx;
         int flush = 1;
+        struct vxlan_sock *vs = container_of(uoff, struct vxlan_sock,
+                                             udp_offloads);
+        u32 flags;
 
         off_vx = skb_gro_offset(skb);
         hlen = off_vx + sizeof(*vh);
@@ -557,6 +600,19 @@ static struct sk_buff **vxlan_gro_receive(struct sk_buff **head,
                         goto out;
         }
 
+        skb_gro_pull(skb, sizeof(struct vxlanhdr)); /* pull vxlan header */
+        skb_gro_postpull_rcsum(skb, vh, sizeof(struct vxlanhdr));
+
+        flags = ntohl(vh->vx_flags);
+
+        if ((flags & VXLAN_HF_RCO) && (vs->flags & VXLAN_F_REMCSUM_RX)) {
+                vh = vxlan_gro_remcsum(skb, off_vx, vh, sizeof(struct vxlanhdr),
+                                       ntohl(vh->vx_vni));
+
+                if (!vh)
+                        goto out;
+        }
+
         flush = 0;
 
         for (p = *head; p; p = p->next) {
@@ -570,8 +626,6 @@ static struct sk_buff **vxlan_gro_receive(struct sk_buff **head,
                 }
         }
 
-        skb_gro_pull(skb, sizeof(struct vxlanhdr));
-        skb_gro_postpull_rcsum(skb, vh, sizeof(struct vxlanhdr));
         pp = eth_gro_receive(head, skb);
 
 out:
@@ -1087,6 +1141,42 @@ static void vxlan_igmp_leave(struct work_struct *work)
         dev_put(vxlan->dev);
 }
 
+static struct vxlanhdr *vxlan_remcsum(struct sk_buff *skb, struct vxlanhdr *vh,
+                                      size_t hdrlen, u32 data)
+{
+        size_t start, offset, plen;
+        __wsum delta;
+
+        if (skb->remcsum_offload) {
+                /* Already processed in GRO path */
+                skb->remcsum_offload = 0;
+                return vh;
+        }
+
+        start = (data & VXLAN_RCO_MASK) << VXLAN_RCO_SHIFT;
+        offset = start + ((data & VXLAN_RCO_UDP) ?
+                          offsetof(struct udphdr, check) :
+                          offsetof(struct tcphdr, check));
+
+        plen = hdrlen + offset + sizeof(u16);
+
+        if (!pskb_may_pull(skb, plen))
+                return NULL;
+
+        vh = (struct vxlanhdr *)(udp_hdr(skb) + 1);
+
+        if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE))
+                __skb_checksum_complete(skb);
+
+        delta = remcsum_adjust((void *)vh + hdrlen,
+                               skb->csum, start, offset);
+
+        /* Adjust skb->csum since we changed the packet */
+        skb->csum = csum_add(skb->csum, delta);
+
+        return vh;
+}
+
 /* Callback from net/ipv4/udp.c to receive packets */
 static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 {
@@ -1111,12 +1201,22 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 
         if (iptunnel_pull_header(skb, VXLAN_HLEN, htons(ETH_P_TEB)))
                 goto drop;
+        vxh = (struct vxlanhdr *)(udp_hdr(skb) + 1);
 
         vs = rcu_dereference_sk_user_data(sk);
         if (!vs)
                 goto drop;
 
-        if (flags || (vni & 0xff)) {
+        if ((flags & VXLAN_HF_RCO) && (vs->flags & VXLAN_F_REMCSUM_RX)) {
+                vxh = vxlan_remcsum(skb, vxh, sizeof(struct vxlanhdr), vni);
+                if (!vxh)
+                        goto drop;
+
+                flags &= ~VXLAN_HF_RCO;
+                vni &= VXLAN_VID_MASK;
+        }
+
+        if (flags || (vni & ~VXLAN_VID_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
@@ -1553,8 +1653,23 @@ static int vxlan6_xmit_skb(struct vxlan_sock *vs,
         int min_headroom;
         int err;
         bool udp_sum = !udp_get_no_check6_tx(vs->sock->sk);
+        int type = udp_sum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
+        u16 hdrlen = sizeof(struct vxlanhdr);
+
+        if ((vs->flags & VXLAN_F_REMCSUM_TX) &&
+            skb->ip_summed == CHECKSUM_PARTIAL) {
+                int csum_start = skb_checksum_start_offset(skb);
+
+                if (csum_start <= VXLAN_MAX_REMCSUM_START &&
+                    !(csum_start & VXLAN_RCO_SHIFT_MASK) &&
+                    (skb->csum_offset == offsetof(struct udphdr, check) ||
+                     skb->csum_offset == offsetof(struct tcphdr, check))) {
+                        udp_sum = false;
+                        type |= SKB_GSO_TUNNEL_REMCSUM;
+                }
+        }
 
-        skb = udp_tunnel_handle_offloads(skb, udp_sum);
+        skb = iptunnel_handle_offloads(skb, udp_sum, type);
         if (IS_ERR(skb)) {
                 err = -EINVAL;
                 goto err;
@@ -1583,6 +1698,22 @@ static int vxlan6_xmit_skb(struct vxlan_sock *vs,
         vxh->vx_flags = htonl(VXLAN_HF_VNI);
         vxh->vx_vni = vni;
 
+        if (type & SKB_GSO_TUNNEL_REMCSUM) {
+                u32 data = (skb_checksum_start_offset(skb) - hdrlen) >>
+                           VXLAN_RCO_SHIFT;
+
+                if (skb->csum_offset == offsetof(struct udphdr, check))
+                        data |= VXLAN_RCO_UDP;
+
+                vxh->vx_vni |= htonl(data);
+                vxh->vx_flags |= htonl(VXLAN_HF_RCO);
+
+                if (!skb_is_gso(skb)) {
+                        skb->ip_summed = CHECKSUM_NONE;
+                        skb->encapsulation = 0;
+                }
+        }
+
         skb_set_inner_protocol(skb, htons(ETH_P_TEB));
 
         udp_tunnel6_xmit_skb(vs->sock, dst, skb, dev, saddr, daddr, prio,
@@ -1603,8 +1734,23 @@ int vxlan_xmit_skb(struct vxlan_sock *vs,
         int min_headroom;
         int err;
         bool udp_sum = !vs->sock->sk->sk_no_check_tx;
+        int type = udp_sum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
+        u16 hdrlen = sizeof(struct vxlanhdr);
+
+        if ((vs->flags & VXLAN_F_REMCSUM_TX) &&
+            skb->ip_summed == CHECKSUM_PARTIAL) {
+                int csum_start = skb_checksum_start_offset(skb);
+
+                if (csum_start <= VXLAN_MAX_REMCSUM_START &&
+                    !(csum_start & VXLAN_RCO_SHIFT_MASK) &&
+                    (skb->csum_offset == offsetof(struct udphdr, check) ||
+                     skb->csum_offset == offsetof(struct tcphdr, check))) {
+                        udp_sum = false;
+                        type |= SKB_GSO_TUNNEL_REMCSUM;
+                }
+        }
 
-        skb = udp_tunnel_handle_offloads(skb, udp_sum);
+        skb = iptunnel_handle_offloads(skb, udp_sum, type);
         if (IS_ERR(skb))
                 return PTR_ERR(skb);
 
@@ -1627,6 +1773,22 @@ int vxlan_xmit_skb(struct vxlan_sock *vs,
         vxh->vx_flags = htonl(VXLAN_HF_VNI);
         vxh->vx_vni = vni;
 
+        if (type & SKB_GSO_TUNNEL_REMCSUM) {
+                u32 data = (skb_checksum_start_offset(skb) - hdrlen) >>
+                           VXLAN_RCO_SHIFT;
+
+                if (skb->csum_offset == offsetof(struct udphdr, check))
+                        data |= VXLAN_RCO_UDP;
+
+                vxh->vx_vni |= htonl(data);
+                vxh->vx_flags |= htonl(VXLAN_HF_RCO);
+
+                if (!skb_is_gso(skb)) {
+                        skb->ip_summed = CHECKSUM_NONE;
+                        skb->encapsulation = 0;
+                }
+        }
+
         skb_set_inner_protocol(skb, htons(ETH_P_TEB));
 
         return udp_tunnel_xmit_skb(vs->sock, rt, skb, src, dst, tos,
@@ -2218,6 +2380,8 @@ static const struct nla_policy vxlan_policy[IFLA_VXLAN_MAX + 1] = {
         [IFLA_VXLAN_UDP_CSUM]   = { .type = NLA_U8 },
         [IFLA_VXLAN_UDP_ZERO_CSUM6_TX]  = { .type = NLA_U8 },
         [IFLA_VXLAN_UDP_ZERO_CSUM6_RX]  = { .type = NLA_U8 },
+        [IFLA_VXLAN_REMCSUM_TX] = { .type = NLA_U8 },
+        [IFLA_VXLAN_REMCSUM_RX] = { .type = NLA_U8 },
 };
 
 static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[])
@@ -2339,6 +2503,7 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, __be16 port,
         atomic_set(&vs->refcnt, 1);
         vs->rcv = rcv;
         vs->data = data;
+        vs->flags = flags;
 
         /* Initialize the vxlan udp offloads structure */
         vs->udp_offloads.port = port;
@@ -2533,6 +2698,14 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
             nla_get_u8(data[IFLA_VXLAN_UDP_ZERO_CSUM6_RX]))
                 vxlan->flags |= VXLAN_F_UDP_ZERO_CSUM6_RX;
 
+        if (data[IFLA_VXLAN_REMCSUM_TX] &&
+            nla_get_u8(data[IFLA_VXLAN_REMCSUM_TX]))
+                vxlan->flags |= VXLAN_F_REMCSUM_TX;
+
+        if (data[IFLA_VXLAN_REMCSUM_RX] &&
+            nla_get_u8(data[IFLA_VXLAN_REMCSUM_RX]))
+                vxlan->flags |= VXLAN_F_REMCSUM_RX;
+
         if (vxlan_find_vni(net, vni, use_ipv6 ? AF_INET6 : AF_INET,
                            vxlan->dst_port)) {
                 pr_info("duplicate VNI %u\n", vni);
@@ -2601,6 +2774,8 @@ static size_t vxlan_get_size(const struct net_device *dev)
                 nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_UDP_CSUM */
                 nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_UDP_ZERO_CSUM6_TX */
                 nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_UDP_ZERO_CSUM6_RX */
+                nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_REMCSUM_TX */
+                nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_REMCSUM_RX */
                 0;
 }
 
@@ -2666,7 +2841,11 @@ static int vxlan_fill_info(struct sk_buff *skb, const struct net_device *dev)
             nla_put_u8(skb, IFLA_VXLAN_UDP_ZERO_CSUM6_TX,
                         !!(vxlan->flags & VXLAN_F_UDP_ZERO_CSUM6_TX)) ||
             nla_put_u8(skb, IFLA_VXLAN_UDP_ZERO_CSUM6_RX,
-                        !!(vxlan->flags & VXLAN_F_UDP_ZERO_CSUM6_RX)))
+                        !!(vxlan->flags & VXLAN_F_UDP_ZERO_CSUM6_RX)) ||
+            nla_put_u8(skb, IFLA_VXLAN_REMCSUM_TX,
+                        !!(vxlan->flags & VXLAN_F_REMCSUM_TX)) ||
+            nla_put_u8(skb, IFLA_VXLAN_REMCSUM_RX,
+                        !!(vxlan->flags & VXLAN_F_REMCSUM_RX)))
                 goto nla_put_failure;
 
         if (nla_put(skb, IFLA_VXLAN_PORT_RANGE, sizeof(ports), &ports))
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index a0d80736224f..0a7443b49133 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -19,6 +19,14 @@ struct vxlanhdr {
 
 /* VXLAN header flags. */
 #define VXLAN_HF_VNI 0x08000000
+#define VXLAN_HF_RCO 0x00200000
+
+/* Remote checksum offload header option */
+#define VXLAN_RCO_MASK  0x7f    /* Last byte of vni field */
+#define VXLAN_RCO_UDP   0x80    /* Indicate UDP RCO (TCP when not set *) */
+#define VXLAN_RCO_SHIFT 1       /* Left shift of start */
+#define VXLAN_RCO_SHIFT_MASK ((1 << VXLAN_RCO_SHIFT) - 1)
+#define VXLAN_MAX_REMCSUM_START (VXLAN_RCO_MASK << VXLAN_RCO_SHIFT)
 
 #define VXLAN_N_VID     (1u << 24)
 #define VXLAN_VID_MASK  (VXLAN_N_VID - 1)
@@ -38,6 +46,7 @@ struct vxlan_sock {
         struct hlist_head vni_list[VNI_HASH_SIZE];
         atomic_t          refcnt;
         struct udp_offload udp_offloads;
+        u32               flags;
 };
 
 #define VXLAN_F_LEARN                   0x01
@@ -49,6 +58,8 @@ struct vxlan_sock {
 #define VXLAN_F_UDP_CSUM                0x40
 #define VXLAN_F_UDP_ZERO_CSUM6_TX       0x80
 #define VXLAN_F_UDP_ZERO_CSUM6_RX       0x100
+#define VXLAN_F_REMCSUM_TX              0x200
+#define VXLAN_F_REMCSUM_RX              0x400
 
 struct vxlan_sock *vxlan_sock_add(struct net *net, __be16 port,
                                   vxlan_rcv_t *rcv, void *data,
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index f7d0d2d7173a..b2723f65846f 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -370,6 +370,8 @@ enum {
         IFLA_VXLAN_UDP_CSUM,
         IFLA_VXLAN_UDP_ZERO_CSUM6_TX,
         IFLA_VXLAN_UDP_ZERO_CSUM6_RX,
+        IFLA_VXLAN_REMCSUM_TX,
+        IFLA_VXLAN_REMCSUM_RX,
         __IFLA_VXLAN_MAX
 };
 #define IFLA_VXLAN_MAX  (__IFLA_VXLAN_MAX - 1)