diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2016-07-03 02:28:47 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-07-05 02:08:40 +0300 |
| commit | 13c5c240f789bbd2bcacb14a23771491485ae61f (patch) | |
| tree | ecf47dfa74f483b539c325e1b95d3772e38e0107 /net | |
| parent | 6fd980ac39efee9c26b1eb256c3271fcb139bd99 (diff) | |
| download | linux-13c5c240f789bbd2bcacb14a23771491485ae61f.tar.xz | |
bpf: add bpf_get_hash_recalc helper
If skb_clear_hash() was invoked due to mangling of relevant headers and
BPF program needs skb->hash later on, we can add a helper to trigger hash
recalculation via bpf_get_hash_recalc().
The helper will return the newly retrieved hash directly, but later access
can also be done via skb context again through skb->hash directly (inline)
without needing to call the helper once more.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/filter.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 54071cf70fb5..10c4a2f9e8bb 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1729,6 +1729,23 @@ static const struct bpf_func_proto bpf_get_route_realm_proto = { .arg1_type = ARG_PTR_TO_CTX, }; +static u64 bpf_get_hash_recalc(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + /* If skb_clear_hash() was called due to mangling, we can + * trigger SW recalculation here. Later access to hash + * can then use the inline skb->hash via context directly + * instead of calling this helper again. + */ + return skb_get_hash((struct sk_buff *) (unsigned long) r1); +} + +static const struct bpf_func_proto bpf_get_hash_recalc_proto = { + .func = bpf_get_hash_recalc, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + static u64 bpf_skb_vlan_push(u64 r1, u64 r2, u64 vlan_tci, u64 r4, u64 r5) { struct sk_buff *skb = (struct sk_buff *) (long) r1; @@ -2337,6 +2354,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) return &bpf_redirect_proto; case BPF_FUNC_get_route_realm: return &bpf_get_route_realm_proto; + case BPF_FUNC_get_hash_recalc: + return &bpf_get_hash_recalc_proto; case BPF_FUNC_perf_event_output: return bpf_get_event_output_proto(); case BPF_FUNC_get_smp_processor_id: |