tun: TUN_VNET_LE support, fix sparse warnings for virtio headers

Pretty straight-forward: convert all fields to/from
virtio endian-ness.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>

1 files changed, 29 insertions, 19 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 36be4fd0cd23..c052bd6b2f23 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -111,7 +111,7 @@ do {								\
 #define TUN_FASYNC      IFF_ATTACH_QUEUE
 
 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
-                      IFF_MULTI_QUEUE)
+                      IFF_VNET_LE | IFF_MULTI_QUEUE)
 #define GOODCOPY_LEN 128
 
 #define FLT_EXACT_COUNT 8
@@ -205,6 +205,16 @@ struct tun_struct {
         u32 flow_count;
 };
 
+static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
+{
+        return __virtio16_to_cpu(tun->flags & IFF_VNET_LE, val);
+}
+
+static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
+{
+        return __cpu_to_virtio16(tun->flags & IFF_VNET_LE, val);
+}
+
 static inline u32 tun_hashfn(u32 rxhash)
 {
         return rxhash & 0x3ff;
@@ -1053,10 +1063,10 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
                         return -EFAULT;
 
                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
-                    gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
-                        gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
+                    tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
+                        gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
 
-                if (gso.hdr_len > len)
+                if (tun16_to_cpu(tun, gso.hdr_len) > len)
                         return -EINVAL;
                 offset += tun->vnet_hdr_sz;
         }
@@ -1064,7 +1074,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
         if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
                 align += NET_IP_ALIGN;
                 if (unlikely(len < ETH_HLEN ||
-                             (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
+                             (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
                         return -EINVAL;
         }
 
@@ -1075,7 +1085,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
                  * enough room for skb expand head in case it is used.
                  * The rest of the buffer is mapped from userspace.
                  */
-                copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN;
+                copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
                 if (copylen > good_linear)
                         copylen = good_linear;
                 linear = copylen;
@@ -1085,10 +1095,10 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 
         if (!zerocopy) {
                 copylen = len;
-                if (gso.hdr_len > good_linear)
+                if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
                         linear = good_linear;
                 else
-                        linear = gso.hdr_len;
+                        linear = tun16_to_cpu(tun, gso.hdr_len);
         }
 
         skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
@@ -1115,8 +1125,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
         }
 
         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
-                if (!skb_partial_csum_set(skb, gso.csum_start,
-                                          gso.csum_offset)) {
+                if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start),
+                                          tun16_to_cpu(tun, gso.csum_offset))) {
                         tun->dev->stats.rx_frame_errors++;
                         kfree_skb(skb);
                         return -EINVAL;
@@ -1184,7 +1194,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 
-                skb_shinfo(skb)->gso_size = gso.gso_size;
+                skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size);
                 if (skb_shinfo(skb)->gso_size == 0) {
                         tun->dev->stats.rx_frame_errors++;
                         kfree_skb(skb);
@@ -1276,8 +1286,8 @@ static ssize_t tun_put_user(struct tun_struct *tun,
                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 
                         /* This is a hint as to how much should be linear. */
-                        gso.hdr_len = skb_headlen(skb);
-                        gso.gso_size = sinfo->gso_size;
+                        gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb));
+                        gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size);
                         if (sinfo->gso_type & SKB_GSO_TCPV4)
                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
@@ -1285,12 +1295,12 @@ static ssize_t tun_put_user(struct tun_struct *tun,
                         else {
                                 pr_err("unexpected GSO type: "
                                        "0x%x, gso_size %d, hdr_len %d\n",
-                                       sinfo->gso_type, gso.gso_size,
-                                       gso.hdr_len);
+                                       sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
+                                       tun16_to_cpu(tun, gso.hdr_len));
                                 print_hex_dump(KERN_ERR, "tun: ",
                                                DUMP_PREFIX_NONE,
                                                16, 1, skb->head,
-                                               min((int)gso.hdr_len, 64), true);
+                                               min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
                                 WARN_ON_ONCE(1);
                                 return -EINVAL;
                         }
@@ -1301,9 +1311,9 @@ static ssize_t tun_put_user(struct tun_struct *tun,
 
                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
-                        gso.csum_start = skb_checksum_start_offset(skb) +
-                                         vlan_hlen;
-                        gso.csum_offset = skb->csum_offset;
+                        gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) +
+                                                      vlan_hlen);
+                        gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
                 } /* else everything is zero */