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Commit 7a4b28c6 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

bpf: add helper to invalidate hash 



Add a small helper that complements 36bbef52 ("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: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 669dc4d7

include/uapi/linux/bpf.h

+7 −0
Original line number Diff line number Diff line
@@ -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,

};

net/core/filter.c

+18 −0
Original line number Diff line number Diff line
@@ -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: