diff mbox series

[bpf-next,09/13] bpf: add bpf_skc_to_udp6_sock() helper

Message ID 20200617211548.1856431-1-yhs@fb.com
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series implement bpf iterator for tcp and udp sockets | expand

Commit Message

Yonghong Song June 17, 2020, 9:15 p.m. UTC 
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: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf.h            |  1 +
 include/uapi/linux/bpf.h       |  9 ++++++++-
 kernel/trace/bpf_trace.c       |  2 ++
 net/core/filter.c              | 26 ++++++++++++++++++++++++++
 scripts/bpf_helpers_doc.py     |  2 ++
 tools/include/uapi/linux/bpf.h |  9 ++++++++-
 6 files changed, 47 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 64059f91e8d7..ca4c7816a2e2 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1642,6 +1642,7 @@  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);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e256417d94c2..3f4b12c5c563 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3276,6 +3276,12 @@  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),			\
@@ -3417,7 +3423,8 @@  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
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index de5fbe66e1ca..d10ab16c4a2f 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -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 ?
diff --git a/net/core/filter.c b/net/core/filter.c
index 03c0e2e34805..a5f41a6852af 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -9301,6 +9301,28 @@  const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto = {
 	.ret_btf_id		= &bpf_skc_to_tcp_request_sock_ret_btf_id,
 };
 
+BPF_CALL_1(bpf_skc_to_udp6_sock, struct sock *, sk)
+{
+	/* add an explicit cast to struct udp6_sock to force
+	 * debug_info type generation for it.
+	 */
+	if (sk_fullsock(sk) && sk->sk_protocol == IPPROTO_UDP &&
+	    sk->sk_family == AF_INET6)
+		return (unsigned long)(struct udp6_sock *)sk;
+
+	return (unsigned long)NULL;
+}
+
+static int bpf_skc_to_udp6_sock_ret_btf_id;
+const struct bpf_func_proto bpf_skc_to_udp6_sock_proto = {
+	.func			= bpf_skc_to_udp6_sock,
+	.gpl_only		= true,
+	.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		= &bpf_skc_to_udp6_sock_ret_btf_id,
+};
+
 void init_sock_cast_types(struct btf *btf)
 {
 	char *ret_type_name;
@@ -9325,4 +9347,8 @@  void init_sock_cast_types(struct btf *btf)
 	ret_type_name = "tcp_request_sock";
 	find_array_of_btf_ids(btf, &ret_type_name,
 			      &bpf_skc_to_tcp_request_sock_ret_btf_id, 1);
+
+	ret_type_name = "udp6_sock";
+	find_array_of_btf_ids(btf, &ret_type_name,
+			      &bpf_skc_to_udp6_sock_ret_btf_id, 1);
 }
diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py
index d886657c6aaa..6bab40ff442e 100755
--- a/scripts/bpf_helpers_doc.py
+++ b/scripts/bpf_helpers_doc.py
@@ -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',
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e256417d94c2..3f4b12c5c563 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3276,6 +3276,12 @@  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),			\
@@ -3417,7 +3423,8 @@  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