Commit 478cfbdf authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Add bpf_skc_to_{tcp, tcp_timewait, tcp_request}_sock() helpers 



Three more helpers are added to cast a sock_common pointer to
an tcp_sock, tcp_timewait_sock or a tcp_request_sock for
tracing programs.

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>
Link: https://lore.kernel.org/bpf/20200623230811.3988277-1-yhs@fb.com
parent af7ec138

include/linux/bpf.h

+3 −0
Original line number Diff line number Diff line
@@ -1650,6 +1650,9 @@ extern const struct bpf_func_proto bpf_ringbuf_submit_proto; 
extern const struct bpf_func_proto bpf_ringbuf_discard_proto;

extern const struct bpf_func_proto bpf_ringbuf_query_proto;

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;



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

+22 −1
Original line number Diff line number Diff line
@@ -3261,6 +3261,24 @@ union bpf_attr { 
 *		Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.

 *	Return

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

 *

 * struct tcp_sock *bpf_skc_to_tcp_sock(void *sk)

 *	Description

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

 *	Return

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

 *

 * struct tcp_timewait_sock *bpf_skc_to_tcp_timewait_sock(void *sk)

 * 	Description

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

 *	Return

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

 *

 * struct tcp_request_sock *bpf_skc_to_tcp_request_sock(void *sk)

 * 	Description

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

 *	Return

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

 */

#define __BPF_FUNC_MAPPER(FN)		\

	FN(unspec),			\
@@ -3399,7 +3417,10 @@ union bpf_attr { 
	FN(ringbuf_discard),		\

	FN(ringbuf_query),		\

	FN(csum_level),			\

	FN(skc_to_tcp6_sock),

	FN(skc_to_tcp6_sock),		\

	FN(skc_to_tcp_sock),		\

	FN(skc_to_tcp_timewait_sock),	\

	FN(skc_to_tcp_request_sock),



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

 * function eBPF program intends to call

kernel/trace/bpf_trace.c

+6 −0
Original line number Diff line number Diff line
@@ -1517,6 +1517,12 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		return &bpf_xdp_output_proto;

	case BPF_FUNC_skc_to_tcp6_sock:

		return &bpf_skc_to_tcp6_sock_proto;

	case BPF_FUNC_skc_to_tcp_sock:

		return &bpf_skc_to_tcp_sock_proto;

	case BPF_FUNC_skc_to_tcp_timewait_sock:

		return &bpf_skc_to_tcp_timewait_sock_proto;

	case BPF_FUNC_skc_to_tcp_request_sock:

		return &bpf_skc_to_tcp_request_sock_proto;

#endif

	case BPF_FUNC_seq_printf:

		return prog->expected_attach_type == BPF_TRACE_ITER ?

net/core/filter.c

+62 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ 
#include <net/lwtunnel.h>

#include <net/ipv6_stubs.h>

#include <net/bpf_sk_storage.h>

#include <net/transp_v6.h>



/**

 *	sk_filter_trim_cap - run a packet through a socket filter
@@ -9307,3 +9308,64 @@ const struct bpf_func_proto bpf_skc_to_tcp6_sock_proto = { 
	.check_btf_id		= check_arg_btf_id,

	.ret_btf_id		= &btf_sock_ids[BTF_SOCK_TYPE_TCP6],

};



BPF_CALL_1(bpf_skc_to_tcp_sock, struct sock *, sk)

{

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

		return (unsigned long)sk;



	return (unsigned long)NULL;

}



const struct bpf_func_proto bpf_skc_to_tcp_sock_proto = {

	.func			= bpf_skc_to_tcp_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_TCP],

};



BPF_CALL_1(bpf_skc_to_tcp_timewait_sock, struct sock *, sk)

{

	if (sk->sk_prot == &tcp_prot && sk->sk_state == TCP_TIME_WAIT)

		return (unsigned long)sk;



#if IS_BUILTIN(CONFIG_IPV6)

	if (sk->sk_prot == &tcpv6_prot && sk->sk_state == TCP_TIME_WAIT)

		return (unsigned long)sk;

#endif



	return (unsigned long)NULL;

}



const struct bpf_func_proto bpf_skc_to_tcp_timewait_sock_proto = {

	.func			= bpf_skc_to_tcp_timewait_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_TCP_TW],

};



BPF_CALL_1(bpf_skc_to_tcp_request_sock, struct sock *, sk)

{

	if (sk->sk_prot == &tcp_prot  && sk->sk_state == TCP_NEW_SYN_RECV)

		return (unsigned long)sk;



#if IS_BUILTIN(CONFIG_IPV6)

	if (sk->sk_prot == &tcpv6_prot && sk->sk_state == TCP_NEW_SYN_RECV)

		return (unsigned long)sk;

#endif



	return (unsigned long)NULL;

}



const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto = {

	.func			= bpf_skc_to_tcp_request_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_TCP_REQ],

};

scripts/bpf_helpers_doc.py

+6 −0
Original line number Diff line number Diff line
@@ -422,6 +422,9 @@ class PrinterHelpers(Printer): 
            'struct tcphdr',

            'struct seq_file',

            'struct tcp6_sock',

            'struct tcp_sock',

            'struct tcp_timewait_sock',

            'struct tcp_request_sock',



            'struct __sk_buff',

            'struct sk_msg_md',
@@ -460,6 +463,9 @@ class PrinterHelpers(Printer): 
            'struct tcphdr',

            'struct seq_file',

            'struct tcp6_sock',

            'struct tcp_sock',

            'struct tcp_timewait_sock',

            'struct tcp_request_sock',

    }

    mapped_types = {

            'u8': '__u8',