[PATCH iproute2-next 0/3] bpf: Work around libbpf deprecations

[PATCH iproute2-next 0/3] bpf: Work around libbpf deprecations

[David Ahern]

libbpf is deprecating APIs, so iproute2 needs to adapt. This will be
an on-going effort, especially to handle legacy maps. This is a
starter set for the low handing fruit.

David Ahern (3):
  bpf_glue: Remove use of bpf_load_program from libbpf
  bpf: Export bpf syscall wrapper
  bpf: Remove use of bpf_create_map_xattr

 include/bpf_util.h |  2 ++
 lib/bpf_glue.c     | 15 ++++++++-------
 lib/bpf_legacy.c   | 19 +++++++------------
 lib/bpf_libbpf.c   | 24 ++++++++++++------------
 4 files changed, 29 insertions(+), 31 deletions(-)

-- 
2.24.3 (Apple Git-128)

[PATCH iproute2-next 1/3] bpf_glue: Remove use of bpf_load_program from libbpf

[David Ahern]

bpf_load_program is deprecated starting in v0.7. The preferred
bpf_prog_load requires bpf_prog_load_opts from v0.6. This creates an
ugly scenario for iproute2 to work across libbpf versions from v0.1
and up.

Since bpf_program_load is only used to load the builtin vrf program,
just remove the libbpf call and use the legacy code.

Signed-off-by: David Ahern <dsahern@kernel.org>
---
 lib/bpf_glue.c   | 12 ------------
 lib/bpf_legacy.c |  7 +++++++
 2 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/lib/bpf_glue.c b/lib/bpf_glue.c
index 70d001840f7b..cc3015487c68 100644
--- a/lib/bpf_glue.c
+++ b/lib/bpf_glue.c
@@ -11,18 +11,6 @@
 #include <bpf/bpf.h>
 #endif
 
-int bpf_program_load(enum bpf_prog_type type, const struct bpf_insn *insns,
-		     size_t size_insns, const char *license, char *log,
-		     size_t size_log)
-{
-#ifdef HAVE_LIBBPF
-	return bpf_load_program(type, insns, size_insns / sizeof(struct bpf_insn),
-				license, 0, log, size_log);
-#else
-	return bpf_prog_load_dev(type, insns, size_insns, license, 0, log, size_log);
-#endif
-}
-
 int bpf_program_attach(int prog_fd, int target_fd, enum bpf_attach_type type)
 {
 #ifdef HAVE_LIBBPF
diff --git a/lib/bpf_legacy.c b/lib/bpf_legacy.c
index 6e3891c9f1f1..3779ae90cc1c 100644
--- a/lib/bpf_legacy.c
+++ b/lib/bpf_legacy.c
@@ -1126,6 +1126,13 @@ int bpf_prog_load_dev(enum bpf_prog_type type, const struct bpf_insn *insns,
 	return bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
 }
 
+int bpf_program_load(enum bpf_prog_type type, const struct bpf_insn *insns,
+		     size_t size_insns, const char *license, char *log,
+		     size_t size_log)
+{
+	return bpf_prog_load_dev(type, insns, size_insns, license, 0, log, size_log);
+}
+
 #ifdef HAVE_ELF
 struct bpf_elf_prog {
 	enum bpf_prog_type	type;
-- 
2.24.3 (Apple Git-128)

[PATCH iproute2-next 2/3] bpf: Export bpf syscall wrapper

[David Ahern]

Move bpf syscall wrapper to bpf_glue to make it available to libbpf
based functions.

Signed-off-by: David Ahern <dsahern@kernel.org>
---
 include/bpf_util.h |  2 ++
 lib/bpf_glue.c     | 13 +++++++++++++
 lib/bpf_legacy.c   | 12 ------------
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/include/bpf_util.h b/include/bpf_util.h
index 53acc4106de8..abb9627556ef 100644
--- a/include/bpf_util.h
+++ b/include/bpf_util.h
@@ -287,6 +287,8 @@ int bpf_program_attach(int prog_fd, int target_fd, enum bpf_attach_type type);
 
 int bpf_dump_prog_info(FILE *f, uint32_t id);
 
+int bpf(int cmd, union bpf_attr *attr, unsigned int size);
+
 #ifdef HAVE_ELF
 int bpf_send_map_fds(const char *path, const char *obj);
 int bpf_recv_map_fds(const char *path, int *fds, struct bpf_map_aux *aux,
diff --git a/lib/bpf_glue.c b/lib/bpf_glue.c
index cc3015487c68..c1cf351b7359 100644
--- a/lib/bpf_glue.c
+++ b/lib/bpf_glue.c
@@ -4,13 +4,26 @@
  * Authors:	Hangbin Liu <haliu@redhat.com>
  *
  */
+#include <sys/syscall.h>
 #include <limits.h>
+#include <unistd.h>
 
 #include "bpf_util.h"
 #ifdef HAVE_LIBBPF
 #include <bpf/bpf.h>
 #endif
 
+int bpf(int cmd, union bpf_attr *attr, unsigned int size)
+{
+#ifdef __NR_bpf
+	return syscall(__NR_bpf, cmd, attr, size);
+#else
+	fprintf(stderr, "No bpf syscall, kernel headers too old?\n");
+	errno = ENOSYS;
+	return -1;
+#endif
+}
+
 int bpf_program_attach(int prog_fd, int target_fd, enum bpf_attach_type type)
 {
 #ifdef HAVE_LIBBPF
diff --git a/lib/bpf_legacy.c b/lib/bpf_legacy.c
index 3779ae90cc1c..9bf7c1c493b4 100644
--- a/lib/bpf_legacy.c
+++ b/lib/bpf_legacy.c
@@ -33,7 +33,6 @@
 #include <sys/un.h>
 #include <sys/vfs.h>
 #include <sys/mount.h>
-#include <sys/syscall.h>
 #include <sys/sendfile.h>
 #include <sys/resource.h>
 
@@ -134,17 +133,6 @@ static inline __u64 bpf_ptr_to_u64(const void *ptr)
 	return (__u64)(unsigned long)ptr;
 }
 
-static int bpf(int cmd, union bpf_attr *attr, unsigned int size)
-{
-#ifdef __NR_bpf
-	return syscall(__NR_bpf, cmd, attr, size);
-#else
-	fprintf(stderr, "No bpf syscall, kernel headers too old?\n");
-	errno = ENOSYS;
-	return -1;
-#endif
-}
-
 static int bpf_map_update(int fd, const void *key, const void *value,
 			  uint64_t flags)
 {
-- 
2.24.3 (Apple Git-128)

[PATCH iproute2-next 3/3] bpf: Remove use of bpf_create_map_xattr

[David Ahern]

bpf_create_map_xattr is deprecated in v0.7 in favor of bpf_map_create.
bpf_map_create and its bpf_map_create_opts are not available across the
range of v0.1 and up versions of libbpf, so change create_map to use
the bpf syscall directly.

Signed-off-by: David Ahern <dsahern@kernel.org>
---
 lib/bpf_libbpf.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/lib/bpf_libbpf.c b/lib/bpf_libbpf.c
index 921716aec8c6..f4f98caa1e58 100644
--- a/lib/bpf_libbpf.c
+++ b/lib/bpf_libbpf.c
@@ -54,18 +54,18 @@ static const char *get_bpf_program__section_name(const struct bpf_program *prog)
 static int create_map(const char *name, struct bpf_elf_map *map,
 		      __u32 ifindex, int inner_fd)
 {
-	struct bpf_create_map_attr map_attr = {};
-
-	map_attr.name = name;
-	map_attr.map_type = map->type;
-	map_attr.map_flags = map->flags;
-	map_attr.key_size = map->size_key;
-	map_attr.value_size = map->size_value;
-	map_attr.max_entries = map->max_elem;
-	map_attr.map_ifindex = ifindex;
-	map_attr.inner_map_fd = inner_fd;
-
-	return bpf_create_map_xattr(&map_attr);
+	union bpf_attr attr = {};
+
+	attr.map_type = map->type;
+	strlcpy(attr.map_name, name, sizeof(attr.map_name));
+	attr.map_flags = map->flags;
+	attr.key_size = map->size_key;
+	attr.value_size = map->size_value;
+	attr.max_entries = map->max_elem;
+	attr.map_ifindex = ifindex;
+	attr.inner_map_fd = inner_fd;
+
+	return bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
 }
 
 static int create_map_in_map(struct bpf_object *obj, struct bpf_map *map,
-- 
2.24.3 (Apple Git-128)

Re: [PATCH iproute2-next 0/3] bpf: Work around libbpf deprecations

[patchwork-bot+netdevbpf]

Hello:

This series was applied to iproute2/iproute2-next.git (main)
by David Ahern <dsahern@kernel.org>:

On Sun, 27 Feb 2022 18:58:37 -0700 you wrote:
> libbpf is deprecating APIs, so iproute2 needs to adapt. This will be
> an on-going effort, especially to handle legacy maps. This is a
> starter set for the low handing fruit.
> 
> David Ahern (3):
>   bpf_glue: Remove use of bpf_load_program from libbpf
>   bpf: Export bpf syscall wrapper
>   bpf: Remove use of bpf_create_map_xattr
> 
> [...]

Here is the summary with links:
  - [iproute2-next,1/3] bpf_glue: Remove use of bpf_load_program from libbpf
    https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/commit/?id=873bb9751f84
  - [iproute2-next,2/3] bpf: Export bpf syscall wrapper
    https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/commit/?id=ac4e0913beb1
  - [iproute2-next,3/3] bpf: Remove use of bpf_create_map_xattr
    https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/commit/?id=d9977eafa719

You are awesome, thank you!
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