bpf: libbpf support for msg_push_data

Add support for new bpf_msg_push_data in libbpf.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a2fb333290dccf128ee607651e5df58ca4abb4ac..852dc17ab47a07f2580ade5f9e4a1130ee779c26 100644 (file)
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2240,6 +2240,23 @@ union bpf_attr {
  *             pointer that was returned from bpf_sk_lookup_xxx\ ().
  *     Return
  *             0 on success, or a negative error in case of failure.
+ *
+ * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
+ *     Description
+ *             For socket policies, insert *len* bytes into msg at offset
+ *             *start*.
+ *
+ *             If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
+ *             *msg* it may want to insert metadata or options into the msg.
+ *             This can later be read and used by any of the lower layer BPF
+ *             hooks.
+ *
+ *             This helper may fail if under memory pressure (a malloc
+ *             fails) in these cases BPF programs will get an appropriate
+ *             error and BPF programs will need to handle them.
+ *
+ *     Return
+ *             0 on success, or a negative error in case of failure.
  */
 #define __BPF_FUNC_MAPPER(FN)          \
        FN(unspec),                     \
@@ -2331,7 +2348,8 @@ union bpf_attr {
        FN(sk_release),                 \
        FN(map_push_elem),              \
        FN(map_pop_elem),               \
-       FN(map_peek_elem),
+       FN(map_peek_elem),              \
+       FN(msg_push_data),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call

diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index 6407a3df0f3ba1ab5b4775c36f208d2689fb7c7d..686e57ce40f430fe25f910d5eda49cf0c8236949 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -111,6 +111,8 @@ static int (*bpf_msg_cork_bytes)(void *ctx, int len) =
        (void *) BPF_FUNC_msg_cork_bytes;
 static int (*bpf_msg_pull_data)(void *ctx, int start, int end, int flags) =
        (void *) BPF_FUNC_msg_pull_data;
+static int (*bpf_msg_push_data)(void *ctx, int start, int end, int flags) =
+       (void *) BPF_FUNC_msg_push_data;
 static int (*bpf_bind)(void *ctx, void *addr, int addr_len) =
        (void *) BPF_FUNC_bind;
 static int (*bpf_xdp_adjust_tail)(void *ctx, int offset) =