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bpf: add helper to invalidate hash

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Add a small helper that complements 36bbef52c7 ("bpf: direct packet
write and access for helpers for clsact progs") for invalidating the
current skb->hash after mangling on headers via direct packet write.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2016-09-23 01:28:37 +02:00 committed by David S. Miller
parent 669dc4d76d
commit 7a4b28c6cc
2 changed files with 25 additions and 0 deletions
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7
include/uapi/linux/bpf.h
View File

@ -419,6 +419,13 @@ enum bpf_func_id {
*/
BPF_FUNC_csum_update,
/**
* bpf_set_hash_invalid(skb)
* Invalidate current skb>hash.
* @skb: pointer to skb
*/
BPF_FUNC_set_hash_invalid,
__BPF_FUNC_MAX_ID,
};

18
net/core/filter.c
View File

@ -1777,6 +1777,22 @@ static const struct bpf_func_proto bpf_get_hash_recalc_proto = {
.arg1_type = ARG_PTR_TO_CTX,
};
BPF_CALL_1(bpf_set_hash_invalid, struct sk_buff *, skb)
{
/* After all direct packet write, this can be used once for
* triggering a lazy recalc on next skb_get_hash() invocation.
*/
skb_clear_hash(skb);
return 0;
}
static const struct bpf_func_proto bpf_set_hash_invalid_proto = {
.func = bpf_set_hash_invalid,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
};
BPF_CALL_3(bpf_skb_vlan_push, struct sk_buff *, skb, __be16, vlan_proto,
u16, vlan_tci)
{
@ -2534,6 +2550,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id)
return &bpf_get_route_realm_proto;
case BPF_FUNC_get_hash_recalc:
return &bpf_get_hash_recalc_proto;
case BPF_FUNC_set_hash_invalid:
return &bpf_set_hash_invalid_proto;
case BPF_FUNC_perf_event_output:
return &bpf_skb_event_output_proto;
case BPF_FUNC_get_smp_processor_id: