Commit 0d4fad3e authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Add bpf_skc_to_udp6_sock() helper 



The helper is used in tracing programs to cast a socket
pointer to a udp6_sock pointer.
The return value could be NULL if the casting is illegal.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Cc: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20200623230815.3988481-1-yhs@fb.com
parent 5788b3a0

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -1653,6 +1653,7 @@ extern const struct bpf_func_proto bpf_skc_to_tcp6_sock_proto; 
extern const struct bpf_func_proto bpf_skc_to_tcp_sock_proto;

extern const struct bpf_func_proto bpf_skc_to_tcp_timewait_sock_proto;

extern const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto;

extern const struct bpf_func_proto bpf_skc_to_udp6_sock_proto;



const struct bpf_func_proto *bpf_tracing_func_proto(

	enum bpf_func_id func_id, const struct bpf_prog *prog);

include/uapi/linux/bpf.h

+8 −1
Original line number Diff line number Diff line
@@ -3279,6 +3279,12 @@ union bpf_attr { 
 *		Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.

 *	Return

 *		*sk* if casting is valid, or NULL otherwise.

 *

 * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk)

 * 	Description

 *		Dynamically cast a *sk* pointer to a *udp6_sock* pointer.

 *	Return

 *		*sk* if casting is valid, or NULL otherwise.

 */

#define __BPF_FUNC_MAPPER(FN)		\

	FN(unspec),			\
@@ -3420,7 +3426,8 @@ union bpf_attr { 
	FN(skc_to_tcp6_sock),		\

	FN(skc_to_tcp_sock),		\

	FN(skc_to_tcp_timewait_sock),	\

	FN(skc_to_tcp_request_sock),

	FN(skc_to_tcp_request_sock),	\

	FN(skc_to_udp6_sock),



/* integer value in 'imm' field of BPF_CALL instruction selects which helper

 * function eBPF program intends to call

kernel/trace/bpf_trace.c

+2 −0
Original line number Diff line number Diff line
@@ -1523,6 +1523,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		return &bpf_skc_to_tcp_timewait_sock_proto;

	case BPF_FUNC_skc_to_tcp_request_sock:

		return &bpf_skc_to_tcp_request_sock_proto;

	case BPF_FUNC_skc_to_udp6_sock:

		return &bpf_skc_to_udp6_sock_proto;

#endif

	case BPF_FUNC_seq_printf:

		return prog->expected_attach_type == BPF_TRACE_ITER ?

net/core/filter.c

+22 −0
Original line number Diff line number Diff line
@@ -9369,3 +9369,25 @@ const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto = { 
	.check_btf_id		= check_arg_btf_id,

	.ret_btf_id		= &btf_sock_ids[BTF_SOCK_TYPE_TCP_REQ],

};



BPF_CALL_1(bpf_skc_to_udp6_sock, struct sock *, sk)

{

	/* udp6_sock type is not generated in dwarf and hence btf,

	 * trigger an explicit type generation here.

	 */

	BTF_TYPE_EMIT(struct udp6_sock);

	if (sk_fullsock(sk) && sk->sk_protocol == IPPROTO_UDP &&

	    sk->sk_type == SOCK_DGRAM && sk->sk_family == AF_INET6)

		return (unsigned long)sk;



	return (unsigned long)NULL;

}



const struct bpf_func_proto bpf_skc_to_udp6_sock_proto = {

	.func			= bpf_skc_to_udp6_sock,

	.gpl_only		= false,

	.ret_type		= RET_PTR_TO_BTF_ID_OR_NULL,

	.arg1_type		= ARG_PTR_TO_BTF_ID,

	.check_btf_id		= check_arg_btf_id,

	.ret_btf_id		= &btf_sock_ids[BTF_SOCK_TYPE_UDP6],

};

scripts/bpf_helpers_doc.py

+2 −0
Original line number Diff line number Diff line
@@ -425,6 +425,7 @@ class PrinterHelpers(Printer): 
            'struct tcp_sock',

            'struct tcp_timewait_sock',

            'struct tcp_request_sock',

            'struct udp6_sock',



            'struct __sk_buff',

            'struct sk_msg_md',
@@ -466,6 +467,7 @@ class PrinterHelpers(Printer): 
            'struct tcp_sock',

            'struct tcp_timewait_sock',

            'struct tcp_request_sock',

            'struct udp6_sock',

    }

    mapped_types = {

            'u8': '__u8',

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