* [PATCH bpf-next v3 0/2] Add bpf_skc_to_unix_sock() helper
@ 2021-10-21 13:47 Hengqi Chen
2021-10-21 13:47 ` [PATCH bpf-next v3 1/2] bpf: " Hengqi Chen
2021-10-21 13:47 ` [PATCH bpf-next v3 2/2] selftests/bpf: Test " Hengqi Chen
0 siblings, 2 replies; 3+ messages in thread
From: Hengqi Chen @ 2021-10-21 13:47 UTC (permalink / raw)
To: bpf
Cc: ast, daniel, andrii, yhs, john.fastabend, kafai, songliubraving,
hengqi.chen
This patch set adds a new BPF helper bpf_skc_to_unix_sock().
The helper is used in tracing programs to cast a socket
pointer to a unix_sock pointer.
v2->v3:
- Use abstract socket in selftest (Alexei)
- Run checkpatch script over patches (Andrii)
v1->v2:
- Update selftest, remove trailing spaces changes (Song)
Hengqi Chen (2):
bpf: Add bpf_skc_to_unix_sock() helper
selftests/bpf: Test bpf_skc_to_unix_sock() helper
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 +++
.../bpf/prog_tests/skc_to_unix_sock.c | 54 +++++++++++++++++++
.../bpf/progs/test_skc_to_unix_sock.c | 40 ++++++++++++++
8 files changed, 136 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/skc_to_unix_sock.c
create mode 100644 tools/testing/selftests/bpf/progs/test_skc_to_unix_sock.c
--
2.30.2
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH bpf-next v3 1/2] bpf: Add bpf_skc_to_unix_sock() helper
2021-10-21 13:47 [PATCH bpf-next v3 0/2] Add bpf_skc_to_unix_sock() helper Hengqi Chen
@ 2021-10-21 13:47 ` Hengqi Chen
2021-10-21 13:47 ` [PATCH bpf-next v3 2/2] selftests/bpf: Test " Hengqi Chen
1 sibling, 0 replies; 3+ messages in thread
From: Hengqi Chen @ 2021-10-21 13:47 UTC (permalink / raw)
To: bpf
Cc: ast, daniel, andrii, yhs, john.fastabend, kafai, songliubraving,
hengqi.chen
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@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH bpf-next v3 2/2] selftests/bpf: Test bpf_skc_to_unix_sock() helper
2021-10-21 13:47 [PATCH bpf-next v3 0/2] Add bpf_skc_to_unix_sock() helper Hengqi Chen
2021-10-21 13:47 ` [PATCH bpf-next v3 1/2] bpf: " Hengqi Chen
@ 2021-10-21 13:47 ` Hengqi Chen
1 sibling, 0 replies; 3+ messages in thread
From: Hengqi Chen @ 2021-10-21 13:47 UTC (permalink / raw)
To: bpf
Cc: ast, daniel, andrii, yhs, john.fastabend, kafai, songliubraving,
hengqi.chen
Add a new test which triggers unix_listen kernel function
to test bpf_skc_to_unix_sock helper.
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
---
.../bpf/prog_tests/skc_to_unix_sock.c | 54 +++++++++++++++++++
.../bpf/progs/test_skc_to_unix_sock.c | 40 ++++++++++++++
2 files changed, 94 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/skc_to_unix_sock.c
create mode 100644 tools/testing/selftests/bpf/progs/test_skc_to_unix_sock.c
diff --git a/tools/testing/selftests/bpf/prog_tests/skc_to_unix_sock.c b/tools/testing/selftests/bpf/prog_tests/skc_to_unix_sock.c
new file mode 100644
index 000000000000..3eefdfed1db9
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/skc_to_unix_sock.c
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2021 Hengqi Chen */
+
+#include <test_progs.h>
+#include <sys/un.h>
+#include "test_skc_to_unix_sock.skel.h"
+
+static const char *sock_path = "@skc_to_unix_sock";
+
+void test_skc_to_unix_sock(void)
+{
+ struct test_skc_to_unix_sock *skel;
+ struct sockaddr_un sockaddr;
+ int err, sockfd = 0;
+
+ skel = test_skc_to_unix_sock__open();
+ if (!ASSERT_OK_PTR(skel, "could not open BPF object"))
+ return;
+
+ skel->rodata->my_pid = getpid();
+
+ err = test_skc_to_unix_sock__load(skel);
+ if (!ASSERT_OK(err, "could not load BPF object"))
+ goto cleanup;
+
+ err = test_skc_to_unix_sock__attach(skel);
+ if (!ASSERT_OK(err, "could not attach BPF object"))
+ goto cleanup;
+
+ /* trigger unix_listen */
+ sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (!ASSERT_GT(sockfd, 0, "socket failed"))
+ goto cleanup;
+
+ memset(&sockaddr, 0, sizeof(sockaddr));
+ sockaddr.sun_family = AF_UNIX;
+ strncpy(sockaddr.sun_path, sock_path, strlen(sock_path));
+ sockaddr.sun_path[0] = '\0';
+
+ err = bind(sockfd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
+ if (!ASSERT_OK(err, "bind failed"))
+ goto cleanup;
+
+ err = listen(sockfd, 1);
+ if (!ASSERT_OK(err, "listen failed"))
+ goto cleanup;
+
+ ASSERT_EQ(strcmp(skel->bss->path, sock_path), 0, "bpf_skc_to_unix_sock failed");
+
+cleanup:
+ if (sockfd)
+ close(sockfd);
+ test_skc_to_unix_sock__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_skc_to_unix_sock.c b/tools/testing/selftests/bpf/progs/test_skc_to_unix_sock.c
new file mode 100644
index 000000000000..a408ec95cba4
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_skc_to_unix_sock.c
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2021 Hengqi Chen */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_tracing_net.h"
+
+const volatile pid_t my_pid = 0;
+char path[256] = {};
+
+SEC("fentry/unix_listen")
+int BPF_PROG(unix_listen, struct socket *sock, int backlog)
+{
+ pid_t pid = bpf_get_current_pid_tgid() >> 32;
+ struct unix_sock *unix_sk;
+ int i, len;
+
+ if (pid != my_pid)
+ return 0;
+
+ unix_sk = (struct unix_sock *)bpf_skc_to_unix_sock(sock->sk);
+ if (!unix_sk)
+ return 0;
+
+ if (!UNIX_ABSTRACT(unix_sk))
+ return 0;
+
+ len = unix_sk->addr->len - sizeof(short);
+ path[0] = '@';
+ for (i = 1; i < len; i++) {
+ if (i >= sizeof(struct sockaddr_un))
+ break;
+
+ path[i] = unix_sk->addr->name->sun_path[i];
+ }
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-10-21 13:48 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-10-21 13:47 ` [PATCH bpf-next v3 1/2] bpf: " Hengqi Chen
2021-10-21 13:47 ` [PATCH bpf-next v3 2/2] selftests/bpf: Test " Hengqi Chen
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