Commit 5311591f authored by Anton Protopopov's avatar Anton Protopopov Committed by Alexei Starovoitov
Browse files

bpf: Add support for passing mark with bpf_fib_lookup 



Extend the bpf_fib_lookup() helper by making it to utilize mark if
the BPF_FIB_LOOKUP_MARK flag is set. In order to pass the mark the
four bytes of struct bpf_fib_lookup are used, shared with the
output-only smac/dmac fields.

Signed-off-by: default avatarAnton Protopopov <aspsk@isovalent.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240326101742.17421-2-aspsk@isovalent.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c602f4ca

include/uapi/linux/bpf.h

+18 −2
Original line number Diff line number Diff line
@@ -3394,6 +3394,10 @@ union bpf_attr { 
 *			for the nexthop. If the src addr cannot be derived,

 *			**BPF_FIB_LKUP_RET_NO_SRC_ADDR** is returned. In this

 *			case, *params*->dmac and *params*->smac are not set either.

 *		**BPF_FIB_LOOKUP_MARK**

 *			Use the mark present in *params*->mark for the fib lookup.

 *			This option should not be used with BPF_FIB_LOOKUP_DIRECT,

 *			as it only has meaning for full lookups.

 *

 *		*ctx* is either **struct xdp_md** for XDP programs or

 *		**struct sk_buff** tc cls_act programs.
@@ -7120,6 +7124,7 @@ enum { 
	BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2),

	BPF_FIB_LOOKUP_TBID    = (1U << 3),

	BPF_FIB_LOOKUP_SRC     = (1U << 4),

	BPF_FIB_LOOKUP_MARK    = (1U << 5),

};



enum {
@@ -7197,9 +7202,20 @@ struct bpf_fib_lookup { 
		__u32	tbid;

	};



	union {

		/* input */

		struct {

			__u32	mark;   /* policy routing */

			/* 2 4-byte holes for input */

		};



		/* output: source and dest mac */

		struct {

			__u8	smac[6];	/* ETH_ALEN */

			__u8	dmac[6];	/* ETH_ALEN */

		};

	};

};



struct bpf_redir_neigh {

	/* network family for lookup (AF_INET, AF_INET6) */

net/core/filter.c

+9 −3
Original line number Diff line number Diff line
@@ -5884,6 +5884,9 @@ static int bpf_ipv4_fib_lookup(struct net *net, struct bpf_fib_lookup *params, 


		err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);

	} else {

		if (flags & BPF_FIB_LOOKUP_MARK)

			fl4.flowi4_mark = params->mark;

		else

			fl4.flowi4_mark = 0;

		fl4.flowi4_secid = 0;

		fl4.flowi4_tun_key.tun_id = 0;
@@ -6027,6 +6030,9 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params, 
		err = ipv6_stub->fib6_table_lookup(net, tb, oif, &fl6, &res,

						   strict);

	} else {

		if (flags & BPF_FIB_LOOKUP_MARK)

			fl6.flowi6_mark = params->mark;

		else

			fl6.flowi6_mark = 0;

		fl6.flowi6_secid = 0;

		fl6.flowi6_tun_key.tun_id = 0;
@@ -6105,7 +6111,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params, 


#define BPF_FIB_LOOKUP_MASK (BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT | \

			     BPF_FIB_LOOKUP_SKIP_NEIGH | BPF_FIB_LOOKUP_TBID | \

			     BPF_FIB_LOOKUP_SRC)

			     BPF_FIB_LOOKUP_SRC | BPF_FIB_LOOKUP_MARK)



BPF_CALL_4(bpf_xdp_fib_lookup, struct xdp_buff *, ctx,

	   struct bpf_fib_lookup *, params, int, plen, u32, flags)

tools/include/uapi/linux/bpf.h

+18 −2
Original line number Diff line number Diff line
@@ -3394,6 +3394,10 @@ union bpf_attr { 
 *			for the nexthop. If the src addr cannot be derived,

 *			**BPF_FIB_LKUP_RET_NO_SRC_ADDR** is returned. In this

 *			case, *params*->dmac and *params*->smac are not set either.

 *		**BPF_FIB_LOOKUP_MARK**

 *			Use the mark present in *params*->mark for the fib lookup.

 *			This option should not be used with BPF_FIB_LOOKUP_DIRECT,

 *			as it only has meaning for full lookups.

 *

 *		*ctx* is either **struct xdp_md** for XDP programs or

 *		**struct sk_buff** tc cls_act programs.
@@ -7120,6 +7124,7 @@ enum { 
	BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2),

	BPF_FIB_LOOKUP_TBID    = (1U << 3),

	BPF_FIB_LOOKUP_SRC     = (1U << 4),

	BPF_FIB_LOOKUP_MARK    = (1U << 5),

};



enum {
@@ -7197,9 +7202,20 @@ struct bpf_fib_lookup { 
		__u32	tbid;

	};



	union {

		/* input */

		struct {

			__u32	mark;   /* policy routing */

			/* 2 4-byte holes for input */

		};



		/* output: source and dest mac */

		struct {

			__u8	smac[6];	/* ETH_ALEN */

			__u8	dmac[6];	/* ETH_ALEN */

		};

	};

};



struct bpf_redir_neigh {

	/* network family for lookup (AF_INET, AF_INET6) */