[PATCH 3/6] bpf: implement decoding of BPF_PROG_LOAD fd_array field

[Paul Chaignon]

* src/bpf_attr.h (BPF_PROG_LOAD_struct): Add fd_array field introduced by
Linux kernel commit v5.6-rc1~151^2~46^2~37^2~5.
(expected_BPF_PROG_LOAD_struct_size): Update.
* src/bpf.c (BEGIN_BPF_CMD_DECODER(BPF_PROG_LOAD)): Decode the new field.
* NEWS: Mention this.
* tests/bpf-obj_get_info_by_fd.c (print_prog_load): Update expected
output.
* tests/bpf.c (BPF_PROG_LOAD_checks): Likewise.
* tests/kernel_version.c (print_bpf_attr): Likewise.

Signed-off-by: Paul Chaignon <paul at isovalent.com>
---
 NEWS                           | 2 +-
 src/bpf.c                      | 6 ++++++
 src/bpf_attr.h                 | 6 ++++--
 tests/bpf-obj_get_info_by_fd.c | 2 ++
 tests/bpf.c                    | 5 +++--
 tests/kernel_version.c         | 3 ++-
 6 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/NEWS b/NEWS
index a890f6226..aa6a2385c 100644
--- a/NEWS
+++ b/NEWS
@@ -4,7 +4,7 @@ Noteworthy changes in release ?.?? (????-??-??)
 * Improvements
   * Updated lists of ioctl commands from Linux 5.16.
   * Updated lists of BPF_* constants.
-  * Enhanced decoding of BPF_MAP_CREATE bpf syscall command.
+  * Enhanced decoding of BPF_MAP_CREATE and BPF_PROG_LOAD bpf syscall commands.
 
 * Bug fixes
 
diff --git a/src/bpf.c b/src/bpf.c
index 5c1e7d7ba..c909d93cf 100644
--- a/src/bpf.c
+++ b/src/bpf.c
@@ -414,6 +414,12 @@ BEGIN_BPF_CMD_DECODER(BPF_PROG_LOAD)
 		break;
 	tprint_struct_next();
 	PRINT_FIELD_FD(attr, attach_prog_fd, tcp);
+
+	/* fd_array was added in Linux commit v5.14-rc1~119^2~501^2~2^2~13. */
+	if (len <= offsetof(struct BPF_PROG_LOAD_struct, fd_array))
+		break;
+	tprint_struct_next();
+	PRINT_FIELD_ADDR64(attr, fd_array);
 }
 END_BPF_CMD_DECODER(RVAL_DECODED | RVAL_FD)
 
diff --git a/src/bpf_attr.h b/src/bpf_attr.h
index 7dad083dd..45e866e1e 100644
--- a/src/bpf_attr.h
+++ b/src/bpf_attr.h
@@ -128,11 +128,13 @@ struct BPF_PROG_LOAD_struct {
 	uint32_t line_info_cnt;
 	uint32_t attach_btf_id;
 	uint32_t attach_prog_fd;
+	uint32_t pad;
+	uint64_t ATTRIBUTE_ALIGNED(8) fd_array;
 };
 
 # define BPF_PROG_LOAD_struct_size \
-	offsetofend(struct BPF_PROG_LOAD_struct, attach_prog_fd)
-# define expected_BPF_PROG_LOAD_struct_size 116
+	sizeof(struct BPF_PROG_LOAD_struct)
+# define expected_BPF_PROG_LOAD_struct_size 128
 
 struct BPF_OBJ_PIN_struct {
 	uint64_t ATTRIBUTE_ALIGNED(8) pathname;
diff --git a/tests/bpf-obj_get_info_by_fd.c b/tests/bpf-obj_get_info_by_fd.c
index e2123eeee..95392cd53 100644
--- a/tests/bpf-obj_get_info_by_fd.c
+++ b/tests/bpf-obj_get_info_by_fd.c
@@ -231,6 +231,8 @@ print_prog_load(void *attr_void, size_t size, long rc)
 		printf(", attach_btf_id=0");
 	if (size > offsetof(struct BPF_PROG_LOAD_struct, attach_prog_fd))
 		printf(", attach_prog_fd=0</dev/null>");
+	if (size > offsetof(struct BPF_PROG_LOAD_struct, fd_array))
+		printf(", fd_array=NULL");
 	printf("}, %zu) = ", size);
 	if (rc >= 0)
 		printf("%ld<anon_inode:bpf-prog>\n", rc);
diff --git a/tests/bpf.c b/tests/bpf.c
index befb34cbd..eeba43821 100644
--- a/tests/bpf.c
+++ b/tests/bpf.c
@@ -786,9 +786,9 @@ static struct bpf_attr_check BPF_PROG_LOAD_checks[] = {
 			.line_info_cnt = 0xdad7bef8,
 			.attach_btf_id = 0xdad7befa,
 			.attach_prog_fd = 0xbadc0def,
+			.fd_array = 0xfaceb00c,
 		} },
-		.size = offsetofend(struct BPF_PROG_LOAD_struct,
-				    attach_prog_fd),
+		.size = offsetofend(struct BPF_PROG_LOAD_struct, fd_array),
 		.str = "prog_type=BPF_PROG_TYPE_UNSPEC"
 		       ", insn_cnt=0"
 		       ", insns=NULL"
@@ -810,6 +810,7 @@ static struct bpf_attr_check BPF_PROG_LOAD_checks[] = {
 		       ", line_info_cnt=3671572216"
 		       ", attach_btf_id=3671572218"
 		       ", attach_prog_fd=-1159983633"
+		       ", fd_array=0xfaceb00c"
 	},
 };
 
diff --git a/tests/kernel_version.c b/tests/kernel_version.c
index fc270cd2a..228d3bccd 100644
--- a/tests/kernel_version.c
+++ b/tests/kernel_version.c
@@ -71,7 +71,8 @@ print_bpf_attr(void)
 		", line_info=NULL"
 		", line_info_cnt=0"
 		", attach_btf_id=0"
-		", attach_prog_fd=0}");
+		", attach_prog_fd=0"
+		", fd_array=NULL}");
 }
 
 int
-- 
2.25.1