net: ip6_gre: Split up ip6gre_tnl_link_config()

The function ip6gre_tnl_link_config() is used for setting up
configuration of both ip6gretap and ip6erspan tunnels. Split the
function into the common part and the route-lookup part. The latter then
takes the calculated header length as an argument. This split will allow
the patches down the line to sneak in a custom header length computation
for the ERSPAN tunnel.

Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 12 deletions

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 14c069b59a90..5d0a3b1ee0e9 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1025,12 +1025,11 @@ tx_err:
         return NETDEV_TX_OK;
 }
 
-static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
+static void ip6gre_tnl_link_config_common(struct ip6_tnl *t)
 {
         struct net_device *dev = t->dev;
         struct __ip6_tnl_parm *p = &t->parms;
         struct flowi6 *fl6 = &t->fl.u.ip6;
-        int t_hlen;
 
         if (dev->type != ARPHRD_ETHER) {
                 memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
@@ -1057,12 +1056,13 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
                 dev->flags |= IFF_POINTOPOINT;
         else
                 dev->flags &= ~IFF_POINTOPOINT;
+}
 
-        t->tun_hlen = gre_calc_hlen(t->parms.o_flags);
-
-        t->hlen = t->encap_hlen + t->tun_hlen;
-
-        t_hlen = t->hlen + sizeof(struct ipv6hdr);
+static void ip6gre_tnl_link_config_route(struct ip6_tnl *t, int set_mtu,
+                                         int t_hlen)
+{
+        const struct __ip6_tnl_parm *p = &t->parms;
+        struct net_device *dev = t->dev;
 
         if (p->flags & IP6_TNL_F_CAP_XMIT) {
                 int strict = (ipv6_addr_type(&p->raddr) &
@@ -1094,6 +1094,24 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
         }
 }
 
+static int ip6gre_calc_hlen(struct ip6_tnl *tunnel)
+{
+        int t_hlen;
+
+        tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
+        tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
+
+        t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
+        tunnel->dev->hard_header_len = LL_MAX_HEADER + t_hlen;
+        return t_hlen;
+}
+
+static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
+{
+        ip6gre_tnl_link_config_common(t);
+        ip6gre_tnl_link_config_route(t, set_mtu, ip6gre_calc_hlen(t));
+}
+
 static int ip6gre_tnl_change(struct ip6_tnl *t,
         const struct __ip6_tnl_parm *p, int set_mtu)
 {
@@ -1387,11 +1405,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
                 return ret;
         }
 
-        tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
-        tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
-        t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
-
-        dev->hard_header_len = LL_MAX_HEADER + t_hlen;
+        t_hlen = ip6gre_calc_hlen(tunnel);
         dev->mtu = ETH_DATA_LEN - t_hlen;
         if (dev->type == ARPHRD_ETHER)
                 dev->mtu -= ETH_HLEN;