Merge branch 'erspan-fixes'

Xin Long says:

====================
ip_gre: a bunch of fixes for erspan

This patchset is to fix some issues that could cause 0 or low
performance, and even unexpected truncated packets on erspan.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 5 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 8b837f6f5532..467e44d7587d 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -259,7 +259,6 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
         struct ip_tunnel *tunnel;
         struct erspanhdr *ershdr;
         const struct iphdr *iph;
-        __be32 session_id;
         __be32 index;
         int len;
 
@@ -275,8 +274,7 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
         /* The original GRE header does not have key field,
          * Use ERSPAN 10-bit session ID as key.
          */
-        session_id = cpu_to_be32(ntohs(ershdr->session_id));
-        tpi->key = session_id;
+        tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
         index = ershdr->md.index;
         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
                                   tpi->flags | TUNNEL_KEY,
@@ -733,7 +731,7 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
         if (skb_cow_head(skb, dev->needed_headroom))
                 goto free_skb;
 
-        if (skb->len > dev->mtu) {
+        if (skb->len - dev->hard_header_len > dev->mtu) {
                 pskb_trim(skb, dev->mtu);
                 truncate = true;
         }
@@ -1247,13 +1245,16 @@ static int erspan_tunnel_init(struct net_device *dev)
 
         tunnel->tun_hlen = 8;
         tunnel->parms.iph.protocol = IPPROTO_GRE;
-        t_hlen = tunnel->hlen + sizeof(struct iphdr) + sizeof(struct erspanhdr);
+        tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
+                       sizeof(struct erspanhdr);
+        t_hlen = tunnel->hlen + sizeof(struct iphdr);
 
         dev->needed_headroom = LL_MAX_HEADER + t_hlen + 4;
         dev->mtu = ETH_DATA_LEN - t_hlen - 4;
         dev->features           |= GRE_FEATURES;
         dev->hw_features        |= GRE_FEATURES;
         dev->priv_flags         |= IFF_LIVE_ADDR_CHANGE;
+        netif_keep_dst(dev);
 
         return ip_tunnel_init(dev);
 }