bpf: allow to propagate df in bpf_skb_set_tunnel_key

Added by 9a628224a61b ("ip_tunnel: Add dont fragment flag."), allow to
feed df flag into tunneling facilities (currently supported on TX by
vxlan, geneve and gre) as a hint from eBPF's bpf_skb_set_tunnel_key()
helper.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 2e3e903099043e97669aff0a860c78711e46b61a..21ee6d52016f3aaa3322ec5ab5cf270e420e1e8a 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -330,6 +330,7 @@ enum bpf_func_id {
 
 /* BPF_FUNC_skb_set_tunnel_key flags. */
 #define BPF_F_ZERO_CSUM_TX             (1ULL << 1)
+#define BPF_F_DONT_FRAGMENT            (1ULL << 2)
 
 /* user accessible mirror of in-kernel sk_buff.
  * new fields can only be added to the end of this structure

diff --git a/net/core/filter.c b/net/core/filter.c
index ce4e18dd2c89a3e28f29044fdb250f498476c94c..6c9d15561d0425a31b47acbbec9ef6f8c8337bfa 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1819,7 +1819,8 @@ static u64 bpf_skb_set_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5)
        u8 compat[sizeof(struct bpf_tunnel_key)];
        struct ip_tunnel_info *info;
 
-       if (unlikely(flags & ~(BPF_F_TUNINFO_IPV6 | BPF_F_ZERO_CSUM_TX)))
+       if (unlikely(flags & ~(BPF_F_TUNINFO_IPV6 | BPF_F_ZERO_CSUM_TX |
+                              BPF_F_DONT_FRAGMENT)))
                return -EINVAL;
        if (unlikely(size != sizeof(struct bpf_tunnel_key))) {
                switch (size) {
@@ -1844,6 +1845,9 @@ static u64 bpf_skb_set_tunnel_key(u64 r1, u64 r2, u64 size, u64 flags, u64 r5)
        info->mode = IP_TUNNEL_INFO_TX;
 
        info->key.tun_flags = TUNNEL_KEY | TUNNEL_CSUM;
+       if (flags & BPF_F_DONT_FRAGMENT)
+               info->key.tun_flags |= TUNNEL_DONT_FRAGMENT;
+
        info->key.tun_id = cpu_to_be64(from->tunnel_id);
        info->key.tos = from->tunnel_tos;
        info->key.ttl = from->tunnel_ttl;