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bpf: Add bpf_skc_to_mptcp_sock_proto

Browse source 
This patch implements a new struct bpf_func_proto, named
bpf_skc_to_mptcp_sock_proto. Define a new bpf_id BTF_SOCK_TYPE_MPTCP,
and a new helper bpf_skc_to_mptcp_sock(), which invokes another new
helper bpf_mptcp_sock_from_subflow() in net/mptcp/bpf.c to get struct
mptcp_sock from a given subflow socket.

v2: Emit BTF type, add func_id checks in verifier.c and bpf_trace.c,
remove build check for CONFIG_BPF_JIT
v5: Drop EXPORT_SYMBOL (Martin)

Co-developed-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220519233016.105670-2-mathew.j.martineau@linux.intel.com
This commit is contained in:
Geliang Tang 2022-05-19 16:30:10 -07:00 committed by Andrii Nakryiko
parent 7aa424e02a
commit 3bc253c2e6
11 changed files with 69 additions and 1 deletions
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1
include/linux/bpf.h
View file

@ -2231,6 +2231,7 @@ 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;
extern const struct bpf_func_proto bpf_skc_to_unix_sock_proto;
extern const struct bpf_func_proto bpf_skc_to_mptcp_sock_proto;
extern const struct bpf_func_proto bpf_copy_from_user_proto;
extern const struct bpf_func_proto bpf_snprintf_btf_proto;
extern const struct bpf_func_proto bpf_snprintf_proto;

3
include/linux/btf_ids.h
View file

@ -178,7 +178,8 @@ extern struct btf_id_set name;
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, tcp6_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, udp_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_UNIX, unix_sock)
BTF_SOCK_TYPE(BTF_SOCK_TYPE_UNIX, unix_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_MPTCP, mptcp_sock)
enum {
#define BTF_SOCK_TYPE(name, str) name,

6
include/net/mptcp.h
View file

@ -284,4 +284,10 @@ static inline int mptcpv6_init(void) { return 0; }
static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
#endif
#if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
#else
static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
#endif
#endif /* __NET_MPTCP_H */

7
include/uapi/linux/bpf.h
View file

@ -5172,6 +5172,12 @@ union bpf_attr {
* Return
* Map value associated to *key* on *cpu*, or **NULL** if no entry
* was found or *cpu* is invalid.
*
* struct mptcp_sock *bpf_skc_to_mptcp_sock(void *sk)
* Description
* Dynamically cast a *sk* pointer to a *mptcp_sock* pointer.
* Return
* *sk* if casting is valid, or **NULL** otherwise.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@ -5370,6 +5376,7 @@ union bpf_attr {
FN(ima_file_hash), \
FN(kptr_xchg), \
FN(map_lookup_percpu_elem), \
FN(skc_to_mptcp_sock), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper

1
kernel/bpf/verifier.c
View file

@ -509,6 +509,7 @@ static bool is_ptr_cast_function(enum bpf_func_id func_id)
func_id == BPF_FUNC_skc_to_tcp_sock ||
func_id == BPF_FUNC_skc_to_tcp6_sock ||
func_id == BPF_FUNC_skc_to_udp6_sock ||
func_id == BPF_FUNC_skc_to_mptcp_sock ||
func_id == BPF_FUNC_skc_to_tcp_timewait_sock ||
func_id == BPF_FUNC_skc_to_tcp_request_sock;
}

2
kernel/trace/bpf_trace.c
View file

@ -1705,6 +1705,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_skc_to_udp6_sock_proto;
case BPF_FUNC_skc_to_unix_sock:
return &bpf_skc_to_unix_sock_proto;
case BPF_FUNC_skc_to_mptcp_sock:
return &bpf_skc_to_mptcp_sock_proto;
case BPF_FUNC_sk_storage_get:
return &bpf_sk_storage_get_tracing_proto;
case BPF_FUNC_sk_storage_delete:

18
net/core/filter.c
View file

@ -78,6 +78,7 @@
#include <linux/btf_ids.h>
#include <net/tls.h>
#include <net/xdp.h>
#include <net/mptcp.h>
static const struct bpf_func_proto *
bpf_sk_base_func_proto(enum bpf_func_id func_id);
@ -11281,6 +11282,20 @@ const struct bpf_func_proto bpf_skc_to_unix_sock_proto = {
.ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_UNIX],
};
BPF_CALL_1(bpf_skc_to_mptcp_sock, struct sock *, sk)
{
BTF_TYPE_EMIT(struct mptcp_sock);
return (unsigned long)bpf_mptcp_sock_from_subflow(sk);
}
const struct bpf_func_proto bpf_skc_to_mptcp_sock_proto = {
.func = bpf_skc_to_mptcp_sock,
.gpl_only = false,
.ret_type = RET_PTR_TO_BTF_ID_OR_NULL,
.arg1_type = ARG_PTR_TO_SOCK_COMMON,
.ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_MPTCP],
};
BPF_CALL_1(bpf_sock_from_file, struct file *, file)
{
return (unsigned long)sock_from_file(file);
@ -11323,6 +11338,9 @@ bpf_sk_base_func_proto(enum bpf_func_id func_id)
case BPF_FUNC_skc_to_unix_sock:
func = &bpf_skc_to_unix_sock_proto;
break;
case BPF_FUNC_skc_to_mptcp_sock:
func = &bpf_skc_to_mptcp_sock_proto;
break;
case BPF_FUNC_ktime_get_coarse_ns:
return &bpf_ktime_get_coarse_ns_proto;
default:

2
net/mptcp/Makefile
View file

@ -10,3 +10,5 @@ obj-$(CONFIG_INET_MPTCP_DIAG) += mptcp_diag.o
mptcp_crypto_test-objs := crypto_test.o
mptcp_token_test-objs := token_test.o
obj-$(CONFIG_MPTCP_KUNIT_TEST) += mptcp_crypto_test.o mptcp_token_test.o
obj-$(CONFIG_BPF_SYSCALL) += bpf.o

21
net/mptcp/bpf.c Normal file
View file

@ -0,0 +1,21 @@
// SPDX-License-Identifier: GPL-2.0
/* Multipath TCP
*
* Copyright (c) 2020, Tessares SA.
* Copyright (c) 2022, SUSE.
*
* Author: Nicolas Rybowski <nicolas.rybowski@tessares.net>
*/
#define pr_fmt(fmt) "MPTCP: " fmt
#include <linux/bpf.h>
#include "protocol.h"
struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk)
{
if (sk && sk_fullsock(sk) && sk->sk_protocol == IPPROTO_TCP && sk_is_mptcp(sk))
return mptcp_sk(mptcp_subflow_ctx(sk)->conn);
return NULL;
}

2
scripts/bpf_doc.py
View file

@ -633,6 +633,7 @@ class PrinterHelpers(Printer):
'struct socket',
'struct file',
'struct bpf_timer',
'struct mptcp_sock',
]
known_types = {
'...',
@ -682,6 +683,7 @@ class PrinterHelpers(Printer):
'struct socket',
'struct file',
'struct bpf_timer',
'struct mptcp_sock',
}
mapped_types = {
'u8': '__u8',

7
tools/include/uapi/linux/bpf.h
View file

@ -5172,6 +5172,12 @@ union bpf_attr {
* Return
* Map value associated to *key* on *cpu*, or **NULL** if no entry
* was found or *cpu* is invalid.
*
* struct mptcp_sock *bpf_skc_to_mptcp_sock(void *sk)
* Description
* Dynamically cast a *sk* pointer to a *mptcp_sock* pointer.
* Return
* *sk* if casting is valid, or **NULL** otherwise.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@ -5370,6 +5376,7 @@ union bpf_attr {
FN(ima_file_hash), \
FN(kptr_xchg), \
FN(map_lookup_percpu_elem), \
FN(skc_to_mptcp_sock), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper