Commit 71c99e32 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Alexei Starovoitov
Browse files

bpf/flow_dissector: support ipv6 flow_label and BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL 



Add support for exporting ipv6 flow label via bpf_flow_keys.
Export flow label from bpf_flow.c and also return early when
BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL is passed.

Acked-by: default avatarPetar Penkov <ppenkov@google.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Petar Penkov <ppenkov@google.com>
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ae173a91

include/uapi/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -3533,6 +3533,7 @@ struct bpf_flow_keys { 
		};

	};

	__u32	flags;

	__be32	flow_label;

};



struct bpf_func_info {

net/core/flow_dissector.c

+9 −0
Original line number Diff line number Diff line
@@ -737,6 +737,7 @@ static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys, 
	struct flow_dissector_key_basic *key_basic;

	struct flow_dissector_key_addrs *key_addrs;

	struct flow_dissector_key_ports *key_ports;

	struct flow_dissector_key_tags *key_tags;



	key_control = skb_flow_dissector_target(flow_dissector,

						FLOW_DISSECTOR_KEY_CONTROL,
@@ -781,6 +782,14 @@ static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys, 
		key_ports->src = flow_keys->sport;

		key_ports->dst = flow_keys->dport;

	}



	if (dissector_uses_key(flow_dissector,

			       FLOW_DISSECTOR_KEY_FLOW_LABEL)) {

		key_tags = skb_flow_dissector_target(flow_dissector,

						     FLOW_DISSECTOR_KEY_FLOW_LABEL,

						     target_container);

		key_tags->flow_label = ntohl(flow_keys->flow_label);

	}

}



bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,

tools/include/uapi/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -3530,6 +3530,7 @@ struct bpf_flow_keys { 
		};

	};

	__u32	flags;

	__be32	flow_label;

};



struct bpf_func_info {

tools/testing/selftests/bpf/prog_tests/flow_dissector.c

+46 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
	      "is_encap=%u/%u "						\

	      "ip_proto=0x%x/0x%x "					\

	      "n_proto=0x%x/0x%x "					\

	      "flow_label=0x%x/0x%x "					\

	      "sport=%u/%u "						\

	      "dport=%u/%u\n",						\

	      got.nhoff, expected.nhoff,				\
@@ -30,6 +31,7 @@ 
	      got.is_encap, expected.is_encap,				\

	      got.ip_proto, expected.ip_proto,				\

	      got.n_proto, expected.n_proto,				\

	      got.flow_label, expected.flow_label,			\

	      got.sport, expected.sport,				\

	      got.dport, expected.dport)
@@ -257,6 +259,50 @@ struct test tests[] = { 
			.is_first_frag = true,

		},

	},

	{

		.name = "ipv6-flow-label",

		.pkt.ipv6 = {

			.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),

			.iph.nexthdr = IPPROTO_TCP,

			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),

			.iph.flow_lbl = { 0xb, 0xee, 0xef },

			.tcp.doff = 5,

			.tcp.source = 80,

			.tcp.dest = 8080,

		},

		.keys = {

			.nhoff = ETH_HLEN,

			.thoff = ETH_HLEN + sizeof(struct ipv6hdr),

			.addr_proto = ETH_P_IPV6,

			.ip_proto = IPPROTO_TCP,

			.n_proto = __bpf_constant_htons(ETH_P_IPV6),

			.sport = 80,

			.dport = 8080,

			.flow_label = __bpf_constant_htonl(0xbeeef),

		},

	},

	{

		.name = "ipv6-no-flow-label",

		.pkt.ipv6 = {

			.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),

			.iph.nexthdr = IPPROTO_TCP,

			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),

			.iph.flow_lbl = { 0xb, 0xee, 0xef },

			.tcp.doff = 5,

			.tcp.source = 80,

			.tcp.dest = 8080,

		},

		.keys = {

			.flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,

			.nhoff = ETH_HLEN,

			.thoff = ETH_HLEN + sizeof(struct ipv6hdr),

			.addr_proto = ETH_P_IPV6,

			.ip_proto = IPPROTO_TCP,

			.n_proto = __bpf_constant_htons(ETH_P_IPV6),

			.flow_label = __bpf_constant_htonl(0xbeeef),

		},

		.flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,

	},

};



static int create_tap(const char *ifname)

tools/testing/selftests/bpf/progs/bpf_flow.c

+10 −0
Original line number Diff line number Diff line
@@ -83,6 +83,12 @@ static __always_inline int export_flow_keys(struct bpf_flow_keys *keys, 
	return ret;

}



#define IPV6_FLOWLABEL_MASK		__bpf_constant_htonl(0x000FFFFF)

static inline __be32 ip6_flowlabel(const struct ipv6hdr *hdr)

{

	return *(__be32 *)hdr & IPV6_FLOWLABEL_MASK;

}



static __always_inline void *bpf_flow_dissect_get_header(struct __sk_buff *skb,

							 __u16 hdr_size,

							 void *buffer)
@@ -308,6 +314,10 @@ PROG(IPV6)(struct __sk_buff *skb) 


	keys->thoff += sizeof(struct ipv6hdr);

	keys->ip_proto = ip6h->nexthdr;

	keys->flow_label = ip6_flowlabel(ip6h);



	if (keys->flags & BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)

		return export_flow_keys(keys, BPF_OK);



	return parse_ipv6_proto(skb, ip6h->nexthdr);

}

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