I'm also working on improving bpf.c. Please have a look at:
https://lkml.org/lkml/2016/11/14/1078
Since bpf.c is simple, I think we can add more functions and fixes
gradually, instead of a full copy.
See my inline comment below.
On 2016/11/17 1:43, Joe Stringer wrote:
Extend the tools/ version of libbpf to include all of the functionality
provided in the samples/bpf version.
Signed-off-by: Joe Stringer <j...@ovn.org>
---
v2: Don't shift non-bpf changes across.
Various type cleanups, removal of extraneous declarations
---
tools/lib/bpf/bpf.c | 107 ++++++++++++++++++++------
tools/lib/bpf/bpf.h | 202 +++++++++++++++++++++++++++++++++++++++++++++++--
tools/lib/bpf/libbpf.c | 3 +-
3 files changed, 279 insertions(+), 33 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 4212ed62235b..5e061851ac00 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -20,10 +20,17 @@
*/
#include <stdlib.h>
-#include <memory.h>
+#include <stdio.h>
#include <unistd.h>
#include <asm/unistd.h>
+#include <string.h>
+#include <linux/netlink.h>
#include <linux/bpf.h>
+#include <errno.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <linux/if_packet.h>
+#include <arpa/inet.h>
#include "bpf.h"
Why we need these network related headers?
/*
@@ -53,24 +60,71 @@ static int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
return syscall(__NR_bpf, cmd, attr, size);
}
-int bpf_create_map(enum bpf_map_type map_type, int key_size,
- int value_size, int max_entries)
+int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size,
+ int max_entries, int map_flags)
{
- union bpf_attr attr;
+ union bpf_attr attr = {
+ .map_type = map_type,
+ .key_size = key_size,
+ .value_size = value_size,
+ .max_entries = max_entries,
+ .map_flags = map_flags,
+ };
- memset(&attr, '\0', sizeof(attr));
+ return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
+}
I lost map_flags in original bpf.c. Thanks to your patch. map_flags is
useful
when creating BPF_MAP_TYPE_PERCPU_HASH: BPF_F_NO_PREALLOC is meanful in this
case.
Although it is okay in samples, I still prefer a explicit bzero() or
memset(),
because kernel checks if unused field in this union is zero. However
I'll check
c standard to see how unused field would be initialized.
<SNIP>
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index e8ba54087497..4dba36995771 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -23,16 +23,202 @@
#include <linux/bpf.h>
+struct bpf_insn;
+
int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size,
- int max_entries);
+ int max_entries, int map_flags);
+int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags);
+int bpf_lookup_elem(int fd, void *key, void *value);
+int bpf_delete_elem(int fd, void *key);
+int bpf_get_next_key(int fd, void *key, void *next_key);
+
+int bpf_load_program(enum bpf_prog_type prog_type,
+ const struct bpf_insn *insns, int insn_len,
+ const char *license, int kern_version,
+ char *log_buf, size_t log_buf_sz);
+
+int bpf_obj_pin(int fd, const char *pathname);
+int bpf_obj_get(const char *pathname);
-/* Recommend log buffer size */
#define BPF_LOG_BUF_SIZE 65536
-int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
- size_t insns_cnt, char *license,
- u32 kern_version, char *log_buf,
- size_t log_buf_sz);
-int bpf_map_update_elem(int fd, void *key, void *value,
- u64 flags);
+/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
+
+#define BPF_ALU64_REG(OP, DST, SRC) \
+ ((struct bpf_insn) { \
+ .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
+ .dst_reg = DST, \
+ .src_reg = SRC, \
+ .off = 0, \
+ .imm = 0 })
+
Should we define these macros here? They are in include/linux/filter.h
and duplicated in tools/include/linux/filter.h. Redefining them here
would cause conflict.
Thank you.
