[PATCH mptcp-next v7 0/4] add skc_to_mptcp_sock

[PATCH mptcp-next v7 0/4] add skc_to_mptcp_sock

[Geliang Tang]

v7:
 - parse msk token from the output of 'ip mptcp monitor'.
 - add Nicolas and Matt's SoB tags.

v6:
 - add skc_to_mptcp_sock helper and test

RESEND:
 - fix the CI Build Failure.
v5:
 - fix incorrect token value
 - verify the token in selftest

v4:
 - define bpf_mptcp_sock_proto as a static function, no longer export
   it in linux/bpf.h

v3:
 - use RET_PTR_TO_BTF_ID_OR_NULL instead of RET_PTR_TO_MPTCP_SOCK_OR_NULL
 - add a new bpf_id BTF_SOCK_TYPE_MPTCP

v2:
 - keep RET_PTR_TO_MPTCP_SOCK_OR_NULL. If we use RET_PTR_TO_BTF_ID_OR_NULL
instead of RET_PTR_TO_MPTCP_SOCK_OR_NULL as Alexei suggested, the
"userspace" tests developed by Nicolas will break.

Geliang Tang (4):
  Revert "selftests: bpf: add bpf_mptcp_sock() verifier tests"
  Revert "bpf: add 'bpf_mptcp_sock' structure and helper"
  bpf: add skc_to_mptcp_sock helper
  selftests: bpf: add skc_to_mptcp_sock test

 include/linux/bpf.h                           | 31 +-------
 include/linux/btf_ids.h                       |  3 +-
 include/uapi/linux/bpf.h                      | 14 +---
 kernel/bpf/verifier.c                         | 20 -----
 net/core/filter.c                             | 21 +++++-
 net/mptcp/bpf.c                               | 62 ++--------------
 scripts/bpf_doc.py                            |  4 +-
 tools/include/uapi/linux/bpf.h                | 14 +---
 tools/testing/selftests/bpf/bpf_tcp_helpers.h |  6 ++
 .../testing/selftests/bpf/prog_tests/mptcp.c  | 73 +++++++++++++++++++
 tools/testing/selftests/bpf/progs/mptcp.c     | 19 +++++
 tools/testing/selftests/bpf/verifier/sock.c   | 63 ----------------
 12 files changed, 135 insertions(+), 195 deletions(-)

-- 
2.34.1

[PATCH mptcp-next v7 1/4] Revert "selftests: bpf: add bpf_mptcp_sock() verifier tests"

[Geliang Tang]

This reverts commit f48f0143286db0d8dbded9542d9a2535533dd3b9.
---
 tools/testing/selftests/bpf/verifier/sock.c | 63 ---------------------
 1 file changed, 63 deletions(-)

diff --git a/tools/testing/selftests/bpf/verifier/sock.c b/tools/testing/selftests/bpf/verifier/sock.c
index 1f85588091ab..8c224eac93df 100644
--- a/tools/testing/selftests/bpf/verifier/sock.c
+++ b/tools/testing/selftests/bpf/verifier/sock.c
@@ -731,66 +731,3 @@
 	.result_unpriv = REJECT,
 	.errstr_unpriv = "unknown func",
 },
-{
-	"bpf_mptcp_sock(skops->sk): no !skops->sk check",
-	.insns = {
-	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct bpf_sock_ops, sk)),
-	BPF_EMIT_CALL(BPF_FUNC_mptcp_sock),
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.prog_type = BPF_PROG_TYPE_SOCK_OPS,
-	.result = REJECT,
-	.errstr = "type=sock_or_null expected=sock_common",
-},
-{
-	"bpf_mptcp_sock(skops->sk): no NULL check on ret",
-	.insns = {
-	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct bpf_sock_ops, sk)),
-	BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	BPF_EMIT_CALL(BPF_FUNC_mptcp_sock),
-	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, offsetof(struct bpf_mptcp_sock, token)),
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.prog_type = BPF_PROG_TYPE_SOCK_OPS,
-	.result = REJECT,
-	.errstr = "invalid mem access 'mptcp_sock_or_null'",
-},
-{
-	"bpf_mptcp_sock(skops->sk): msk->token",
-	.insns = {
-	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct bpf_sock_ops, sk)),
-	BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	BPF_EMIT_CALL(BPF_FUNC_mptcp_sock),
-	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
-	BPF_EXIT_INSN(),
-	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, offsetof(struct bpf_mptcp_sock, token)),
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.prog_type = BPF_PROG_TYPE_SOCK_OPS,
-	.result = ACCEPT,
-},
-{
-	"bpf_mptcp_sock(skops->sk): msk->token cannot be modified",
-	.insns = {
-	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct bpf_sock_ops, sk)),
-	BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	BPF_EMIT_CALL(BPF_FUNC_mptcp_sock),
-	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
-	BPF_EXIT_INSN(),
-	BPF_ST_MEM(BPF_W, BPF_REG_0, offsetof(struct bpf_mptcp_sock, token), 0x2a),
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.prog_type = BPF_PROG_TYPE_SOCK_OPS,
-	.result = REJECT,
-	.errstr = "cannot write into mptcp_sock",
-},
-- 
2.34.1

[PATCH mptcp-next v7 2/4] Revert "bpf: add 'bpf_mptcp_sock' structure and helper"

[Geliang Tang]

This reverts commit 2ee22ce38ed4c7a416ce887eb6379aaf157634f9.
---
 include/linux/bpf.h            | 34 ----------------
 include/uapi/linux/bpf.h       | 13 ------
 kernel/bpf/verifier.c          | 20 ----------
 net/core/filter.c              |  4 --
 net/mptcp/Makefile             |  2 -
 net/mptcp/bpf.c                | 72 ----------------------------------
 scripts/bpf_doc.py             |  2 -
 tools/include/uapi/linux/bpf.h | 13 ------
 8 files changed, 160 deletions(-)
 delete mode 100644 net/mptcp/bpf.c

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 5a17c1e3a6bc..f19abc59b6cd 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -407,7 +407,6 @@ enum bpf_return_type {
 	RET_PTR_TO_MAP_VALUE,		/* returns a pointer to map elem value */
 	RET_PTR_TO_SOCKET,		/* returns a pointer to a socket */
 	RET_PTR_TO_TCP_SOCK,		/* returns a pointer to a tcp_sock */
-	RET_PTR_TO_MPTCP_SOCK,		/* returns a pointer to mptcp_sock */
 	RET_PTR_TO_SOCK_COMMON,		/* returns a pointer to a sock_common */
 	RET_PTR_TO_ALLOC_MEM,		/* returns a pointer to dynamically allocated memory */
 	RET_PTR_TO_MEM_OR_BTF_ID,	/* returns a pointer to a valid memory or a btf_id */
@@ -418,7 +417,6 @@ enum bpf_return_type {
 	RET_PTR_TO_MAP_VALUE_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_MAP_VALUE,
 	RET_PTR_TO_SOCKET_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_SOCKET,
 	RET_PTR_TO_TCP_SOCK_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_TCP_SOCK,
-	RET_PTR_TO_MPTCP_SOCK_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_MPTCP_SOCK,
 	RET_PTR_TO_SOCK_COMMON_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_SOCK_COMMON,
 	RET_PTR_TO_ALLOC_MEM_OR_NULL	= PTR_MAYBE_NULL | MEM_ALLOC | RET_PTR_TO_ALLOC_MEM,
 	RET_PTR_TO_BTF_ID_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_BTF_ID,
@@ -499,7 +497,6 @@ enum bpf_reg_type {
 	PTR_TO_SOCKET,		 /* reg points to struct bpf_sock */
 	PTR_TO_SOCK_COMMON,	 /* reg points to sock_common */
 	PTR_TO_TCP_SOCK,	 /* reg points to struct tcp_sock */
-	PTR_TO_MPTCP_SOCK,	 /* reg points to struct mptcp_sock */
 	PTR_TO_TP_BUFFER,	 /* reg points to a writable raw tp's buffer */
 	PTR_TO_XDP_SOCK,	 /* reg points to struct xdp_sock */
 	/* PTR_TO_BTF_ID points to a kernel struct that does not need
@@ -528,7 +525,6 @@ enum bpf_reg_type {
 	PTR_TO_SOCKET_OR_NULL		= PTR_MAYBE_NULL | PTR_TO_SOCKET,
 	PTR_TO_SOCK_COMMON_OR_NULL	= PTR_MAYBE_NULL | PTR_TO_SOCK_COMMON,
 	PTR_TO_TCP_SOCK_OR_NULL		= PTR_MAYBE_NULL | PTR_TO_TCP_SOCK,
-	PTR_TO_MPTCP_SOCK_OR_NULL	= PTR_MAYBE_NULL | PTR_TO_MPTCP_SOCK,
 	PTR_TO_BTF_ID_OR_NULL		= PTR_MAYBE_NULL | PTR_TO_BTF_ID,
 
 	/* This must be the last entry. Its purpose is to ensure the enum is
@@ -2221,7 +2217,6 @@ extern const struct bpf_func_proto bpf_get_local_storage_proto;
 extern const struct bpf_func_proto bpf_strtol_proto;
 extern const struct bpf_func_proto bpf_strtoul_proto;
 extern const struct bpf_func_proto bpf_tcp_sock_proto;
-extern const struct bpf_func_proto bpf_mptcp_sock_proto;
 extern const struct bpf_func_proto bpf_jiffies64_proto;
 extern const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto;
 extern const struct bpf_func_proto bpf_event_output_data_proto;
@@ -2309,7 +2304,6 @@ struct sk_reuseport_kern {
 	u32 reuseport_id;
 	bool bind_inany;
 };
-
 bool bpf_tcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
 				  struct bpf_insn_access_aux *info);
 
@@ -2360,34 +2354,6 @@ static inline u32 bpf_xdp_sock_convert_ctx_access(enum bpf_access_type type,
 }
 #endif /* CONFIG_INET */
 
-#ifdef CONFIG_MPTCP
-bool bpf_mptcp_sock_is_valid_access(int off, int size,
-				    enum bpf_access_type type,
-				    struct bpf_insn_access_aux *info);
-
-u32 bpf_mptcp_sock_convert_ctx_access(enum bpf_access_type type,
-				      const struct bpf_insn *si,
-				      struct bpf_insn *insn_buf,
-				      struct bpf_prog *prog,
-				      u32 *target_size);
-#else /* CONFIG_MPTCP */
-static inline bool bpf_mptcp_sock_is_valid_access(int off, int size,
-						  enum bpf_access_type type,
-						  struct bpf_insn_access_aux *info)
-{
-	return false;
-}
-
-static inline u32 bpf_mptcp_sock_convert_ctx_access(enum bpf_access_type type,
-						    const struct bpf_insn *si,
-						    struct bpf_insn *insn_buf,
-						    struct bpf_prog *prog,
-						    u32 *target_size)
-{
-	return 0;
-}
-#endif /* CONFIG_MPTCP */
-
 enum bpf_text_poke_type {
 	BPF_MOD_CALL,
 	BPF_MOD_JUMP,
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index f2e5c7bd4f10..3f6dcdf4b915 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5086,14 +5086,6 @@ union bpf_attr {
  *	Return
  *		0 on success, or a negative error in case of failure. On error
  *		*dst* buffer is zeroed out.
- *
- * struct bpf_mptcp_sock *bpf_mptcp_sock(struct bpf_sock *sk)
- *	Description
- *		This helper gets a **struct bpf_mptcp_sock** pointer from a
- *		**struct bpf_sock** pointer.
- *	Return
- *		A **struct bpf_mptcp_sock** pointer on success, or **NULL** in
- *		case of failure.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -5288,7 +5280,6 @@ union bpf_attr {
 	FN(xdp_load_bytes),		\
 	FN(xdp_store_bytes),		\
 	FN(copy_from_user_task),	\
-	FN(mptcp_sock),			\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
@@ -5637,10 +5628,6 @@ struct bpf_tcp_sock {
 	__u32 is_mptcp;		/* Is MPTCP subflow? */
 };
 
-struct bpf_mptcp_sock {
-	__u32 token;		/* msk token */
-};
-
 struct bpf_sock_tuple {
 	union {
 		struct {
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1bb1b5d0419d..d7473fee247c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -430,7 +430,6 @@ static bool type_is_sk_pointer(enum bpf_reg_type type)
 	return type == PTR_TO_SOCKET ||
 		type == PTR_TO_SOCK_COMMON ||
 		type == PTR_TO_TCP_SOCK ||
-		type == PTR_TO_MPTCP_SOCK ||
 		type == PTR_TO_XDP_SOCK;
 }
 
@@ -438,7 +437,6 @@ static bool reg_type_not_null(enum bpf_reg_type type)
 {
 	return type == PTR_TO_SOCKET ||
 		type == PTR_TO_TCP_SOCK ||
-		type == PTR_TO_MPTCP_SOCK ||
 		type == PTR_TO_MAP_VALUE ||
 		type == PTR_TO_MAP_KEY ||
 		type == PTR_TO_SOCK_COMMON;
@@ -454,7 +452,6 @@ static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
 {
 	return base_type(type) == PTR_TO_SOCKET ||
 		base_type(type) == PTR_TO_TCP_SOCK ||
-		base_type(type) == PTR_TO_MPTCP_SOCK ||
 		base_type(type) == PTR_TO_MEM ||
 		base_type(type) == PTR_TO_BTF_ID;
 }
@@ -554,7 +551,6 @@ static const char *reg_type_str(struct bpf_verifier_env *env,
 		[PTR_TO_SOCKET]		= "sock",
 		[PTR_TO_SOCK_COMMON]	= "sock_common",
 		[PTR_TO_TCP_SOCK]	= "tcp_sock",
-		[PTR_TO_MPTCP_SOCK]	= "mptcp_sock",
 		[PTR_TO_TP_BUFFER]	= "tp_buffer",
 		[PTR_TO_XDP_SOCK]	= "xdp_sock",
 		[PTR_TO_BTF_ID]		= "ptr_",
@@ -2778,7 +2774,6 @@ static bool is_spillable_regtype(enum bpf_reg_type type)
 	case PTR_TO_SOCKET:
 	case PTR_TO_SOCK_COMMON:
 	case PTR_TO_TCP_SOCK:
-	case PTR_TO_MPTCP_SOCK:
 	case PTR_TO_XDP_SOCK:
 	case PTR_TO_BTF_ID:
 	case PTR_TO_BUF:
@@ -3671,9 +3666,6 @@ static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
 	case PTR_TO_TCP_SOCK:
 		valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
 		break;
-	case PTR_TO_MPTCP_SOCK:
-		valid = bpf_mptcp_sock_is_valid_access(off, size, t, &info);
-		break;
 	case PTR_TO_XDP_SOCK:
 		valid = bpf_xdp_sock_is_valid_access(off, size, t, &info);
 		break;
@@ -3830,9 +3822,6 @@ static int check_ptr_alignment(struct bpf_verifier_env *env,
 	case PTR_TO_TCP_SOCK:
 		pointer_desc = "tcp_sock ";
 		break;
-	case PTR_TO_MPTCP_SOCK:
-		pointer_desc = "mptcp_sock ";
-		break;
 	case PTR_TO_XDP_SOCK:
 		pointer_desc = "xdp_sock ";
 		break;
@@ -6762,9 +6751,6 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 	} else if (base_type(ret_type) == RET_PTR_TO_TCP_SOCK) {
 		mark_reg_known_zero(env, regs, BPF_REG_0);
 		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
-	} else if (base_type(ret_type) == RET_PTR_TO_MPTCP_SOCK) {
-		mark_reg_known_zero(env, regs, BPF_REG_0);
-		regs[BPF_REG_0].type = PTR_TO_MPTCP_SOCK | ret_flag;
 	} else if (base_type(ret_type) == RET_PTR_TO_ALLOC_MEM) {
 		mark_reg_known_zero(env, regs, BPF_REG_0);
 		regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
@@ -7479,7 +7465,6 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 	case PTR_TO_SOCKET:
 	case PTR_TO_SOCK_COMMON:
 	case PTR_TO_TCP_SOCK:
-	case PTR_TO_MPTCP_SOCK:
 	case PTR_TO_XDP_SOCK:
 		verbose(env, "R%d pointer arithmetic on %s prohibited\n",
 			dst, reg_type_str(env, ptr_reg->type));
@@ -10854,7 +10839,6 @@ static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
 	case PTR_TO_SOCKET:
 	case PTR_TO_SOCK_COMMON:
 	case PTR_TO_TCP_SOCK:
-	case PTR_TO_MPTCP_SOCK:
 	case PTR_TO_XDP_SOCK:
 		/* Only valid matches are exact, which memcmp() above
 		 * would have accepted
@@ -11385,7 +11369,6 @@ static bool reg_type_mismatch_ok(enum bpf_reg_type type)
 	case PTR_TO_SOCKET:
 	case PTR_TO_SOCK_COMMON:
 	case PTR_TO_TCP_SOCK:
-	case PTR_TO_MPTCP_SOCK:
 	case PTR_TO_XDP_SOCK:
 	case PTR_TO_BTF_ID:
 		return false;
@@ -12810,9 +12793,6 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 		case PTR_TO_TCP_SOCK:
 			convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
 			break;
-		case PTR_TO_MPTCP_SOCK:
-			convert_ctx_access = bpf_mptcp_sock_convert_ctx_access;
-			break;
 		case PTR_TO_XDP_SOCK:
 			convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
 			break;
diff --git a/net/core/filter.c b/net/core/filter.c
index a07b28997ad3..f64454722a7e 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7850,10 +7850,6 @@ sock_ops_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	case BPF_FUNC_tcp_sock:
 		return &bpf_tcp_sock_proto;
 #endif /* CONFIG_INET */
-#ifdef CONFIG_MPTCP
-	case BPF_FUNC_mptcp_sock:
-		return &bpf_mptcp_sock_proto;
-#endif /* CONFIG_MPTCP */
 	default:
 		return bpf_sk_base_func_proto(func_id);
 	}
diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
index 0a0608b6b4b4..48a9d978aaeb 100644
--- a/net/mptcp/Makefile
+++ b/net/mptcp/Makefile
@@ -11,5 +11,3 @@ 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) += bpf.o
diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
deleted file mode 100644
index 5332469fbb28..000000000000
--- a/net/mptcp/bpf.c
+++ /dev/null
@@ -1,72 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/* Multipath TCP
- *
- * Copyright (c) 2020, Tessares SA.
- *
- * Author: Nicolas Rybowski <nicolas.rybowski@tessares.net>
- *
- */
-
-#include <linux/bpf.h>
-
-#include "protocol.h"
-
-bool bpf_mptcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
-				    struct bpf_insn_access_aux *info)
-{
-	if (off < 0 || off >= offsetofend(struct bpf_mptcp_sock, token))
-		return false;
-
-	if (off % size != 0)
-		return false;
-
-	switch (off) {
-	default:
-		return size == sizeof(__u32);
-	}
-}
-
-u32 bpf_mptcp_sock_convert_ctx_access(enum bpf_access_type type,
-				      const struct bpf_insn *si,
-				      struct bpf_insn *insn_buf,
-				      struct bpf_prog *prog, u32 *target_size)
-{
-	struct bpf_insn *insn = insn_buf;
-
-#define BPF_MPTCP_SOCK_GET_COMMON(FIELD)							\
-	do {											\
-		BUILD_BUG_ON(sizeof_field(struct mptcp_sock, FIELD) >				\
-				sizeof_field(struct bpf_mptcp_sock, FIELD));			\
-		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct mptcp_sock, FIELD),		\
-							si->dst_reg, si->src_reg,		\
-							offsetof(struct mptcp_sock, FIELD));	\
-	} while (0)
-
-	if (insn > insn_buf)
-		return insn - insn_buf;
-
-	switch (si->off) {
-	case offsetof(struct bpf_mptcp_sock, token):
-		BPF_MPTCP_SOCK_GET_COMMON(token);
-		break;
-	}
-
-	return insn - insn_buf;
-}
-
-BPF_CALL_1(bpf_mptcp_sock, struct sock *, sk)
-{
-	if (sk_fullsock(sk) && sk->sk_protocol == IPPROTO_TCP && sk_is_mptcp(sk)) {
-		struct mptcp_subflow_context *mptcp_sfc = mptcp_subflow_ctx(sk);
-
-		return (unsigned long)mptcp_sfc->conn;
-	}
-	return (unsigned long)NULL;
-}
-
-const struct bpf_func_proto bpf_mptcp_sock_proto = {
-	.func           = bpf_mptcp_sock,
-	.gpl_only       = false,
-	.ret_type       = RET_PTR_TO_MPTCP_SOCK_OR_NULL,
-	.arg1_type      = ARG_PTR_TO_SOCK_COMMON,
-};
diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
index 6ef5c44a2a9e..096625242475 100755
--- a/scripts/bpf_doc.py
+++ b/scripts/bpf_doc.py
@@ -623,7 +623,6 @@ class PrinterHelpers(Printer):
             'struct udp6_sock',
             'struct unix_sock',
             'struct task_struct',
-            'struct bpf_mptcp_sock',
 
             'struct __sk_buff',
             'struct sk_msg_md',
@@ -683,7 +682,6 @@ class PrinterHelpers(Printer):
             'struct socket',
             'struct file',
             'struct bpf_timer',
-            'struct bpf_mptcp_sock',
     }
     mapped_types = {
             'u8': '__u8',
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index f2e5c7bd4f10..3f6dcdf4b915 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5086,14 +5086,6 @@ union bpf_attr {
  *	Return
  *		0 on success, or a negative error in case of failure. On error
  *		*dst* buffer is zeroed out.
- *
- * struct bpf_mptcp_sock *bpf_mptcp_sock(struct bpf_sock *sk)
- *	Description
- *		This helper gets a **struct bpf_mptcp_sock** pointer from a
- *		**struct bpf_sock** pointer.
- *	Return
- *		A **struct bpf_mptcp_sock** pointer on success, or **NULL** in
- *		case of failure.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -5288,7 +5280,6 @@ union bpf_attr {
 	FN(xdp_load_bytes),		\
 	FN(xdp_store_bytes),		\
 	FN(copy_from_user_task),	\
-	FN(mptcp_sock),			\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
@@ -5637,10 +5628,6 @@ struct bpf_tcp_sock {
 	__u32 is_mptcp;		/* Is MPTCP subflow? */
 };
 
-struct bpf_mptcp_sock {
-	__u32 token;		/* msk token */
-};
-
 struct bpf_sock_tuple {
 	union {
 		struct {
-- 
2.34.1

[PATCH mptcp-next v7 3/4] bpf: add skc_to_mptcp_sock helper

[Geliang Tang]

This patch implemented bpf_skc_to_mptcp_sock helper. Defined a new bpf_id
BTF_SOCK_TYPE_MPTCP, and added a new helper bpf_mptcp_sock_from_subflow()
to get struct bpf_mptcp_sock from a given subflow socket.

Co-developed-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 include/linux/bpf.h            |  9 +++++++++
 include/linux/btf_ids.h        |  3 ++-
 include/uapi/linux/bpf.h       |  7 +++++++
 net/core/filter.c              | 17 +++++++++++++++++
 net/mptcp/Makefile             |  2 ++
 net/mptcp/bpf.c                | 20 ++++++++++++++++++++
 scripts/bpf_doc.py             |  2 ++
 tools/include/uapi/linux/bpf.h |  7 +++++++
 8 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 net/mptcp/bpf.c

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index f19abc59b6cd..b28b3d8c3df2 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2354,6 +2354,15 @@ static inline u32 bpf_xdp_sock_convert_ctx_access(enum bpf_access_type type,
 }
 #endif /* CONFIG_INET */
 
+#ifdef CONFIG_MPTCP
+struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
+#else /* CONFIG_MPTCP */
+static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk)
+{
+	return NULL;
+}
+#endif /* CONFIG_MPTCP */
+
 enum bpf_text_poke_type {
 	BPF_MOD_CALL,
 	BPF_MOD_JUMP,
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index bc5d9cc34e4c..335a19092368 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -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,
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 3f6dcdf4b915..a88aac4457a9 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5086,6 +5086,12 @@ union bpf_attr {
  *	Return
  *		0 on success, or a negative error in case of failure. On error
  *		*dst* buffer is zeroed out.
+ *
+ * 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),			\
@@ -5280,6 +5286,7 @@ union bpf_attr {
 	FN(xdp_load_bytes),		\
 	FN(xdp_store_bytes),		\
 	FN(copy_from_user_task),	\
+	FN(skc_to_mptcp_sock),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/net/core/filter.c b/net/core/filter.c
index f64454722a7e..538b6db4fd76 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -11121,6 +11121,19 @@ 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)
+{
+	return (unsigned long)bpf_mptcp_sock_from_subflow(sk);
+}
+
+static 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);
@@ -11163,6 +11176,10 @@ 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;
+#ifdef CONFIG_MPTCP
+	case BPF_FUNC_skc_to_mptcp_sock:
+		return &bpf_skc_to_mptcp_sock_proto;
+#endif /* CONFIG_MPTCP */
 	case BPF_FUNC_ktime_get_coarse_ns:
 		return &bpf_ktime_get_coarse_ns_proto;
 	default:
diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
index 48a9d978aaeb..0a0608b6b4b4 100644
--- a/net/mptcp/Makefile
+++ b/net/mptcp/Makefile
@@ -11,3 +11,5 @@ 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) += bpf.o
diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
new file mode 100644
index 000000000000..da79dae559b2
--- /dev/null
+++ b/net/mptcp/bpf.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2020, Tessares SA.
+ *
+ * Author: Nicolas Rybowski <nicolas.rybowski@tessares.net>
+ *
+ */
+
+#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;
+}
+EXPORT_SYMBOL(bpf_mptcp_sock_from_subflow);
diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
index 096625242475..0e5a9e69ae59 100755
--- a/scripts/bpf_doc.py
+++ b/scripts/bpf_doc.py
@@ -623,6 +623,7 @@ class PrinterHelpers(Printer):
             'struct udp6_sock',
             'struct unix_sock',
             'struct task_struct',
+            'struct mptcp_sock',
 
             'struct __sk_buff',
             'struct sk_msg_md',
@@ -682,6 +683,7 @@ class PrinterHelpers(Printer):
             'struct socket',
             'struct file',
             'struct bpf_timer',
+            'struct mptcp_sock',
     }
     mapped_types = {
             'u8': '__u8',
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 3f6dcdf4b915..a88aac4457a9 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5086,6 +5086,12 @@ union bpf_attr {
  *	Return
  *		0 on success, or a negative error in case of failure. On error
  *		*dst* buffer is zeroed out.
+ *
+ * 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),			\
@@ -5280,6 +5286,7 @@ union bpf_attr {
 	FN(xdp_load_bytes),		\
 	FN(xdp_store_bytes),		\
 	FN(copy_from_user_task),	\
+	FN(skc_to_mptcp_sock),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
-- 
2.34.1

[PATCH mptcp-next v7 4/4] selftests: bpf: add skc_to_mptcp_sock test

[Geliang Tang]

This patch extended the MPTCP test base, to exercise the new helper
bpf_skc_to_mptcp_sock() from C test as Alexei suggested in v3.

Added a new function verify_msk() to verify the msk token, and a new
function get_msk_token() to parse the msk token from the output of the
command 'ip mptcp monitor'.

Co-developed-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 tools/testing/selftests/bpf/bpf_tcp_helpers.h |  6 ++
 .../testing/selftests/bpf/prog_tests/mptcp.c  | 73 +++++++++++++++++++
 tools/testing/selftests/bpf/progs/mptcp.c     | 19 +++++
 3 files changed, 98 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_tcp_helpers.h b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
index b1ede6f0b821..05f62f81cc4d 100644
--- a/tools/testing/selftests/bpf/bpf_tcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
@@ -83,6 +83,12 @@ struct tcp_sock {
 	__u64	tcp_mstamp;	/* most recent packet received/sent */
 } __attribute__((preserve_access_index));
 
+struct mptcp_sock {
+	struct inet_connection_sock	sk;
+
+	__u32	token;
+} __attribute__((preserve_access_index));
+
 static __always_inline struct inet_connection_sock *inet_csk(const struct sock *sk)
 {
 	return (struct inet_connection_sock *)sk;
diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index 04aef0f147dc..d60525d5124f 100644
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -3,9 +3,12 @@
 #include "cgroup_helpers.h"
 #include "network_helpers.h"
 
+char monitor_log_path[64];
+
 struct mptcp_storage {
 	__u32 invoked;
 	__u32 is_mptcp;
+	__u32 token;
 };
 
 static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 is_mptcp)
@@ -42,6 +45,62 @@ static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 is_mptcp)
 	return err;
 }
 
+static __u32 get_msk_token(void)
+{
+	char *prefix = "[       CREATED] token=";
+	char buf[32] = {};
+	__u32 token = 0;
+	ssize_t len;
+	int fd;
+
+	fd = open(monitor_log_path, O_RDONLY);
+	if (CHECK_FAIL(fd < 0)) {
+		log_err("Failed to open %s", monitor_log_path);
+		goto err;
+	}
+
+	len = read(fd, buf, sizeof(buf));
+	if (CHECK_FAIL(len < 0)) {
+		log_err("Failed to read %s", monitor_log_path);
+		goto err;
+	}
+
+	if (strncmp(buf, prefix, strlen(prefix))) {
+		log_err("Invalid prefix %s", buf);
+		goto err;
+	}
+
+	token = strtol(buf + strlen(prefix), NULL, 16);
+
+err:
+	close(fd);
+	return token;
+}
+
+static int verify_msk(int map_fd, int client_fd, __u32 token)
+{
+	int err = 0, cfd = client_fd;
+	struct mptcp_storage val;
+
+	if (token <= 0) {
+		log_err("Unexpected token %x", token);
+		return -1;
+	}
+
+	if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &cfd, &val) < 0)) {
+		perror("Failed to read socket storage");
+		return -1;
+	}
+
+	if (val.token != token) {
+		log_err("Unexpected mptcp_sock.token %x != %x",
+			val.token, token);
+		err++;
+	}
+
+	return err;
+}
+
 static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
 {
 	int client_fd, prog_fd, map_fd, err;
@@ -79,6 +138,9 @@ static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
 	err += is_mptcp ? verify_sk(map_fd, client_fd, "MPTCP subflow socket", 1) :
 			  verify_sk(map_fd, client_fd, "plain TCP socket", 0);
 
+	if (is_mptcp)
+		err += verify_msk(map_fd, client_fd, get_msk_token());
+
 close_client_fd:
 	close(client_fd);
 
@@ -89,7 +151,9 @@ static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
 
 void test_mptcp(void)
 {
+	char tmp_dir[] = "/tmp/XXXXXX";
 	int server_fd, cgroup_fd;
+	char cmd[256];
 
 	cgroup_fd = test__join_cgroup("/mptcp");
 	if (CHECK_FAIL(cgroup_fd < 0))
@@ -106,6 +170,13 @@ void test_mptcp(void)
 
 with_mptcp:
 	/* with MPTCP */
+	if (CHECK_FAIL(!mkdtemp(tmp_dir)))
+		goto close_cgroup_fd;
+	snprintf(monitor_log_path, sizeof(monitor_log_path),
+		 "%s/ip_mptcp_monitor", tmp_dir);
+	snprintf(cmd, sizeof(cmd), "ip mptcp monitor > %s &", monitor_log_path);
+	if (CHECK_FAIL(system(cmd)))
+		goto close_cgroup_fd;
 	server_fd = start_mptcp_server(AF_INET, NULL, 0, 0);
 	if (CHECK_FAIL(server_fd < 0))
 		goto close_cgroup_fd;
@@ -113,6 +184,8 @@ void test_mptcp(void)
 	CHECK_FAIL(run_test(cgroup_fd, server_fd, true));
 
 	close(server_fd);
+	snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir);
+	system(cmd);
 
 close_cgroup_fd:
 	close(cgroup_fd);
diff --git a/tools/testing/selftests/bpf/progs/mptcp.c b/tools/testing/selftests/bpf/progs/mptcp.c
index be5ee8dac2b3..7ddb73dc69a2 100644
--- a/tools/testing/selftests/bpf/progs/mptcp.c
+++ b/tools/testing/selftests/bpf/progs/mptcp.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/bpf.h>
 #include <bpf/bpf_helpers.h>
+#include "bpf_tcp_helpers.h"
 
 char _license[] SEC("license") = "GPL";
 __u32 _version SEC("version") = 1;
@@ -8,6 +9,7 @@ __u32 _version SEC("version") = 1;
 struct mptcp_storage {
 	__u32 invoked;
 	__u32 is_mptcp;
+	__u32 token;
 };
 
 struct {
@@ -44,5 +46,22 @@ int _sockops(struct bpf_sock_ops *ctx)
 	storage->invoked++;
 	storage->is_mptcp = tcp_sk->is_mptcp;
 
+	if (tcp_sk->is_mptcp) {
+		char fmt[] = "msk=%p token=%x\n";
+		struct mptcp_sock *msk;
+
+		msk = bpf_skc_to_mptcp_sock(sk);
+		if (!msk)
+			return 1;
+
+		storage = bpf_sk_storage_get(&socket_storage_map, msk, 0,
+					     BPF_SK_STORAGE_GET_F_CREATE);
+		if (!storage)
+			return 1;
+
+		storage->token = msk->token;
+		bpf_trace_printk(fmt, sizeof(fmt), msk, storage->token);
+	}
+
 	return 1;
 }
-- 
2.34.1

Re: selftests: bpf: add skc_to_mptcp_sock test: Tests Results

[MPTCP CI]

Hi Geliang,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal:
  - Success! ✅:
  - Task: https://cirrus-ci.com/task/4692010903797760
  - Summary: https://api.cirrus-ci.com/v1/artifact/task/4692010903797760/summary/summary.txt

- KVM Validation: debug:
  - Unstable: 1 failed test(s): selftest_diag 🔴:
  - Task: https://cirrus-ci.com/task/5817910810640384
  - Summary: https://api.cirrus-ci.com/v1/artifact/task/5817910810640384/summary/summary.txt

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/eb83e0f5a1ff

Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (Tessares)

Re: [PATCH mptcp-next v7 4/4] selftests: bpf: add skc_to_mptcp_sock test

[Matthieu Baerts]

Hi Geliang,

Thank you for the new version!

I think we are almost there, just some small stuff in this patch 4/4.

On 08/03/2022 05:02, Geliang Tang wrote:
> This patch extended the MPTCP test base, to exercise the new helper
> bpf_skc_to_mptcp_sock() from C test as Alexei suggested in v3.

May you eventually add a link to this review? It might help to
remembering what was said in 2020 :)

> Added a new function verify_msk() to verify the msk token, and a new
> function get_msk_token() to parse the msk token from the output of the
> command 'ip mptcp monitor'.

I hope it is OK for BPF maintainers to use 'ip mptcp monitor' but I see
they already use 'ip' commands from .c code in other BPF tests.

> diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> index 04aef0f147dc..d60525d5124f 100644
> --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> @@ -3,9 +3,12 @@
>  #include "cgroup_helpers.h"
>  #include "network_helpers.h"
>  
> +char monitor_log_path[64];
> +
>  struct mptcp_storage {
>  	__u32 invoked;
>  	__u32 is_mptcp;
> +	__u32 token;
>  };
>  
>  static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 is_mptcp)
> @@ -42,6 +45,62 @@ static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 is_mptcp)
>  	return err;
>  }
>  
> +static __u32 get_msk_token(void)
> +{
> +	char *prefix = "[       CREATED] token=";
> +	char buf[32] = {};
> +	__u32 token = 0;
> +	ssize_t len;
> +	int fd;
> +
> +	fd = open(monitor_log_path, O_RDONLY);
> +	if (CHECK_FAIL(fd < 0)) {
> +		log_err("Failed to open %s", monitor_log_path);
> +		goto err;
> +	}
> +
> +	len = read(fd, buf, sizeof(buf));
> +	if (CHECK_FAIL(len < 0)) {
> +		log_err("Failed to read %s", monitor_log_path);
> +		goto err;
> +	}
> +
> +	if (strncmp(buf, prefix, strlen(prefix))) {
> +		log_err("Invalid prefix %s", buf);
> +		goto err;
> +	}
> +
> +	token = strtol(buf + strlen(prefix), NULL, 16);

I don't know if it is safe to do that: if I'm not mistaken, 'buf' will
not end with a '\0'. If you expect a token written in 8 char and a
"prefix" of 24 chars -- total = 32 char + '\0' --, probably best to have
a buffer of 33 bytes, read 32 and make sure the 33th is set to 0
(already the case with your initialisation), no?

> +
> +err:
> +	close(fd);
> +	return token;
> +}
> +
> +static int verify_msk(int map_fd, int client_fd, __u32 token)
> +{
> +	int err = 0, cfd = client_fd;
> +	struct mptcp_storage val;
> +
> +	if (token <= 0) {
> +		log_err("Unexpected token %x", token);
> +		return -1;
> +	}
> +
> +	if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &cfd, &val) < 0)) {
> +		perror("Failed to read socket storage");
> +		return -1;
> +	}

I think you should also check the value of val.invoked and val.mptcp
like above, probably in a common function (verify_sk()? see below). That
would help in case of issues with this test.

> +
> +	if (val.token != token) {
> +		log_err("Unexpected mptcp_sock.token %x != %x",
> +			val.token, token);
> +		err++;
> +	}
> +
> +	return err;
> +}
> +
>  static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
>  {
>  	int client_fd, prog_fd, map_fd, err;
> @@ -79,6 +138,9 @@ static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
>  	err += is_mptcp ? verify_sk(map_fd, client_fd, "MPTCP subflow socket", 1) :
>  			  verify_sk(map_fd, client_fd, "plain TCP socket", 0);

There is still a comment about MPTCP socket in verify_sk which no longer
makes sense I think.

What do you think about renaming verify_sk to verify_tsk() which would
be dedicated to TCP (only taking map_fd and client_fd args) and
verify_msk() for MPTCP?

In other words, for MPTCP sockets, you would only call verify_msk().

  err += is_mptcp ? verify_msk(map_fd, client_fd) :
                    verify_tsk(map_fd, client_fd);

In this case you can remove the comment about MPTCP in verify_sk().

>  
> +	if (is_mptcp)
> +		err += verify_msk(map_fd, client_fd, get_msk_token());
> +
>  close_client_fd:
>  	close(client_fd);

Cheers,
Matt
-- 
Tessares | Belgium | Hybrid Access Solutions
www.tessares.net