net: ip_gre: use erspan key field for tunnel lookup

Use ERSPAN key header field as tunnel key in gre_parse_header routine
since ERSPAN protocol sets the key field of the external GRE header to
0 resulting in a tunnel lookup fail in ip6gre_err.
In addition remove key field parsing and pskb_may_pull check in
erspan_rcv and ip6erspan_rcv

Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index a4bf22e..7c4a41d 100644 (file)
--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -25,6 +25,7 @@
 #include <linux/spinlock.h>
 #include <net/protocol.h>
 #include <net/gre.h>
+#include <net/erspan.h>
 
 #include <net/icmp.h>
 #include <net/route.h>
@@ -119,6 +120,22 @@ int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
                        hdr_len += 4;
        }
        tpi->hdr_len = hdr_len;
+
+       /* ERSPAN ver 1 and 2 protocol sets GRE key field
+        * to 0 and sets the configured key in the
+        * inner erspan header field
+        */
+       if (greh->protocol == htons(ETH_P_ERSPAN) ||
+           greh->protocol == htons(ETH_P_ERSPAN2)) {
+               struct erspan_base_hdr *ershdr;
+
+               if (!pskb_may_pull(skb, nhs + hdr_len + sizeof(*ershdr)))
+                       return -EINVAL;
+
+               ershdr = (struct erspan_base_hdr *)options;
+               tpi->key = cpu_to_be32(get_session_id(ershdr));
+       }
+
        return hdr_len;
 }
 EXPORT_SYMBOL(gre_parse_header);

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index b1a74d8..20a64fe 100644 (file)
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -268,20 +268,11 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
        int len;
 
        itn = net_generic(net, erspan_net_id);
-       len = gre_hdr_len + sizeof(*ershdr);
-
-       /* Check based hdr len */
-       if (unlikely(!pskb_may_pull(skb, len)))
-               return PACKET_REJECT;
 
        iph = ip_hdr(skb);
        ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
        ver = ershdr->ver;
 
-       /* The original GRE header does not have key field,
-        * Use ERSPAN 10-bit session ID as key.
-        */
-       tpi->key = cpu_to_be32(get_session_id(ershdr));
        tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
                                  tpi->flags | TUNNEL_KEY,
                                  iph->saddr, iph->daddr, tpi->key);

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index b1be67c..4416368 100644 (file)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -534,13 +534,9 @@ static int ip6erspan_rcv(struct sk_buff *skb, int gre_hdr_len,
        struct ip6_tnl *tunnel;
        u8 ver;
 
-       if (unlikely(!pskb_may_pull(skb, sizeof(*ershdr))))
-               return PACKET_REJECT;
-
        ipv6h = ipv6_hdr(skb);
        ershdr = (struct erspan_base_hdr *)skb->data;
        ver = ershdr->ver;
-       tpi->key = cpu_to_be32(get_session_id(ershdr));
 
        tunnel = ip6gre_tunnel_lookup(skb->dev,
                                      &ipv6h->saddr, &ipv6h->daddr, tpi->key,