The helper is used in tracing programs to cast a socket
pointer to a unix_sock pointer.
The return value could be NULL if the casting is illegal.
Suggested-by: Yonghong Song <yhs@xxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
Signed-off-by: Hengqi Chen <hengqi.chen@xxxxxxxxx>
---
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 7 +++++++
kernel/trace/bpf_trace.c | 2 ++
net/core/filter.c | 23 +++++++++++++++++++++++
scripts/bpf_doc.py | 2 ++
tools/include/uapi/linux/bpf.h | 7 +++++++
6 files changed, 42 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d604c8251d88..be3102b4554b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2093,6 +2093,7 @@ 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;
+extern const struct bpf_func_proto bpf_skc_to_unix_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;
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 6fc59d61937a..22e7a3f38b9f 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4909,6 +4909,12 @@ union bpf_attr {
* Return
* The number of bytes written to the buffer, or a negative error
* in case of failure.
+ *
+ * struct unix_sock *bpf_skc_to_unix_sock(void *sk)
+ * Description
+ * Dynamically cast a *sk* pointer to a *unix_sock* pointer.
+ * Return
+ * *sk* if casting is valid, or **NULL** otherwise.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -5089,6 +5095,7 @@ union bpf_attr {
FN(task_pt_regs), \
FN(get_branch_snapshot), \
FN(trace_vprintk), \
+ FN(skc_to_unix_sock), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 6b3153841a33..cbcd0d6fca7c 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1608,6 +1608,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_skc_to_tcp_request_sock_proto;
case BPF_FUNC_skc_to_udp6_sock:
return &bpf_skc_to_udp6_sock_proto;
+ case BPF_FUNC_skc_to_unix_sock:
+ return &bpf_skc_to_unix_sock_proto;
case BPF_FUNC_sk_storage_get:
return &bpf_sk_storage_get_tracing_proto;
case BPF_FUNC_sk_storage_delete:
diff --git a/net/core/filter.c b/net/core/filter.c
index 4bace37a6a44..8e8d3b49c297 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -10723,6 +10723,26 @@ const struct bpf_func_proto bpf_skc_to_udp6_sock_proto = {
.ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_UDP6],
};
+BPF_CALL_1(bpf_skc_to_unix_sock, struct sock *, sk)
+{
+ /* unix_sock type is not generated in dwarf and hence btf,
+ * trigger an explicit type generation here.
+ */
+ BTF_TYPE_EMIT(struct unix_sock);
+ if (sk && sk_fullsock(sk) && sk->sk_family == AF_UNIX)
+ return (unsigned long)sk;
+
+ return (unsigned long)NULL;
+}
+
+const struct bpf_func_proto bpf_skc_to_unix_sock_proto = {
+ .func = bpf_skc_to_unix_sock,
+ .gpl_only = false,
+ .ret_type = RET_PTR_TO_BTF_ID_OR_NULL,
+ .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
+ .ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_UNIX],
+};
+
BPF_CALL_1(bpf_sock_from_file, struct file *, file)
{
return (unsigned long)sock_from_file(file);
@@ -10762,6 +10782,9 @@ bpf_sk_base_func_proto(enum bpf_func_id func_id)
case BPF_FUNC_skc_to_udp6_sock:
func = &bpf_skc_to_udp6_sock_proto;
break;
+ case BPF_FUNC_skc_to_unix_sock:
+ func = &bpf_skc_to_unix_sock_proto;
+ break;
default:
return bpf_base_func_proto(func_id);
}
diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
index 00ac7b79cddb..a6403ddf5de7 100755
--- a/scripts/bpf_doc.py
+++ b/scripts/bpf_doc.py
@@ -537,6 +537,7 @@ class PrinterHelpers(Printer):
'struct tcp_timewait_sock',
'struct tcp_request_sock',
'struct udp6_sock',
+ 'struct unix_sock',
'struct task_struct',
'struct __sk_buff',
@@ -589,6 +590,7 @@ class PrinterHelpers(Printer):
'struct tcp_timewait_sock',
'struct tcp_request_sock',
'struct udp6_sock',
+ 'struct unix_sock',
'struct task_struct',
'struct path',
'struct btf_ptr',
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 6fc59d61937a..22e7a3f38b9f 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4909,6 +4909,12 @@ union bpf_attr {
* Return
* The number of bytes written to the buffer, or a negative error
* in case of failure.
+ *
+ * struct unix_sock *bpf_skc_to_unix_sock(void *sk)
+ * Description
+ * Dynamically cast a *sk* pointer to a *unix_sock* pointer.
+ * Return
+ * *sk* if casting is valid, or **NULL** otherwise.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -5089,6 +5095,7 @@ union bpf_attr {
FN(task_pt_regs), \
FN(get_branch_snapshot), \
FN(trace_vprintk), \
+ FN(skc_to_unix_sock), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
--
2.30.2
