ip_tunnels, bpf: define IP_TUNNEL_OPTS_MAX and use it

eBPF defines this as BPF_TUNLEN_MAX and OVS just uses the hard-coded
value inside struct sw_flow_key. Thus, add and use IP_TUNNEL_OPTS_MAX
for this, which makes the code a bit more generic and allows to remove
BPF_TUNLEN_MAX from eBPF code.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 5dc2e454f866..c35dda9ec991 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -7,6 +7,8 @@
 #include <linux/socket.h>
 #include <linux/types.h>
 #include <linux/u64_stats_sync.h>
+#include <linux/bitops.h>
+
 #include <net/dsfield.h>
 #include <net/gro_cells.h>
 #include <net/inet_ecn.h>
@@ -57,6 +59,11 @@ struct ip_tunnel_key {
 #define IP_TUNNEL_INFO_TX       0x01    /* represents tx tunnel parameters */
 #define IP_TUNNEL_INFO_IPV6     0x02    /* key contains IPv6 addresses */
 
+/* Maximum tunnel options length. */
+#define IP_TUNNEL_OPTS_MAX                                      \
+        GENMASK((FIELD_SIZEOF(struct ip_tunnel_info,            \
+                              options_len) * BITS_PER_BYTE) - 1, 0)
+
 struct ip_tunnel_info {
         struct ip_tunnel_key    key;
 #ifdef CONFIG_DST_CACHE