Re: [PATCH bpf-next v3 2/4] bpf: Expose bpf_get_socket_cookie to tracing programs
On Tue, 2020-12-08 at 23:08 +0100, KP Singh wrote: > My understanding is you can simply always call sock_gen_cookie and > not have two protos. > > This will disable preemption in sleepable programs and not have any > effect in non-sleepable programs since preemption will already be > disabled. Sure, that works. I thought that providing two helper implems would slightly improve performances on non-sleepable programs but I can send a v4 with only one helper that calls sock_gen_cookie.
Re: [PATCH bpf-next v3 2/4] bpf: Expose bpf_get_socket_cookie to tracing programs
On Tue, Dec 8, 2020 at 9:20 PM Florent Revest wrote:
>
> This needs two new helpers, one that works in a sleepable context (using
> sock_gen_cookie which disables/enables preemption) and one that does not
> (for performance reasons). Both take a struct sock pointer and need to
> check it for NULLness.
>
> This helper could also be useful to other BPF program types such as LSM.
>
> Signed-off-by: Florent Revest
> ---
> include/linux/bpf.h| 2 ++
> include/uapi/linux/bpf.h | 7 +++
> kernel/trace/bpf_trace.c | 4
> net/core/filter.c | 24
> tools/include/uapi/linux/bpf.h | 7 +++
> 5 files changed, 44 insertions(+)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index d05e75ed8c1b..2ecda549b773 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1859,6 +1859,8 @@ extern const struct bpf_func_proto
> bpf_snprintf_btf_proto;
> extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
> extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
> extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
> +extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_sleepable_proto;
> +extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto;
>
> const struct bpf_func_proto *bpf_tracing_func_proto(
> enum bpf_func_id func_id, const struct bpf_prog *prog);
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index ba59309f4d18..9ac66cf25959 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -1667,6 +1667,13 @@ union bpf_attr {
> * Return
> * A 8-byte long unique number.
> *
> + * u64 bpf_get_socket_cookie(void *sk)
> + * Description
> + * Equivalent to **bpf_get_socket_cookie**\ () helper that
> accepts
> + * *sk*, but gets socket from a BTF **struct sock**.
> + * Return
> + * A 8-byte long unique number.
> + *
> * u32 bpf_get_socket_uid(struct sk_buff *skb)
> * Return
> * The owner UID of the socket associated to *skb*. If the socket
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 0cf0a6331482..99accc2146bc 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1778,6 +1778,10 @@ tracing_prog_func_proto(enum bpf_func_id func_id,
> const struct bpf_prog *prog)
> return _sk_storage_get_tracing_proto;
> case BPF_FUNC_sk_storage_delete:
> return _sk_storage_delete_tracing_proto;
> + case BPF_FUNC_get_socket_cookie:
> + return prog->aux->sleepable ?
> + _get_socket_ptr_cookie_sleepable_proto :
> + _get_socket_ptr_cookie_proto;
> #endif
> case BPF_FUNC_seq_printf:
> return prog->expected_attach_type == BPF_TRACE_ITER ?
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 77001a35768f..34877796ab5b 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -4631,6 +4631,30 @@ static const struct bpf_func_proto
> bpf_get_socket_cookie_sock_proto = {
> .arg1_type = ARG_PTR_TO_CTX,
> };
>
> +BPF_CALL_1(bpf_get_socket_ptr_cookie_sleepable, struct sock *, sk)
> +{
> + return sk ? sock_gen_cookie(sk) : 0;
My understanding is you can simply always call sock_gen_cookie and not
have two protos.
This will disable preemption in sleepable programs and not have any effect
in non-sleepable programs since preemption will already be disabled.
[PATCH bpf-next v3 2/4] bpf: Expose bpf_get_socket_cookie to tracing programs
This needs two new helpers, one that works in a sleepable context (using
sock_gen_cookie which disables/enables preemption) and one that does not
(for performance reasons). Both take a struct sock pointer and need to
check it for NULLness.
This helper could also be useful to other BPF program types such as LSM.
Signed-off-by: Florent Revest
---
include/linux/bpf.h| 2 ++
include/uapi/linux/bpf.h | 7 +++
kernel/trace/bpf_trace.c | 4
net/core/filter.c | 24
tools/include/uapi/linux/bpf.h | 7 +++
5 files changed, 44 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d05e75ed8c1b..2ecda549b773 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1859,6 +1859,8 @@ extern const struct bpf_func_proto bpf_snprintf_btf_proto;
extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
+extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_sleepable_proto;
+extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto;
const struct bpf_func_proto *bpf_tracing_func_proto(
enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index ba59309f4d18..9ac66cf25959 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1667,6 +1667,13 @@ union bpf_attr {
* Return
* A 8-byte long unique number.
*
+ * u64 bpf_get_socket_cookie(void *sk)
+ * Description
+ * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
+ * *sk*, but gets socket from a BTF **struct sock**.
+ * Return
+ * A 8-byte long unique number.
+ *
* u32 bpf_get_socket_uid(struct sk_buff *skb)
* Return
* The owner UID of the socket associated to *skb*. If the socket
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 0cf0a6331482..99accc2146bc 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1778,6 +1778,10 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const
struct bpf_prog *prog)
return _sk_storage_get_tracing_proto;
case BPF_FUNC_sk_storage_delete:
return _sk_storage_delete_tracing_proto;
+ case BPF_FUNC_get_socket_cookie:
+ return prog->aux->sleepable ?
+ _get_socket_ptr_cookie_sleepable_proto :
+ _get_socket_ptr_cookie_proto;
#endif
case BPF_FUNC_seq_printf:
return prog->expected_attach_type == BPF_TRACE_ITER ?
diff --git a/net/core/filter.c b/net/core/filter.c
index 77001a35768f..34877796ab5b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4631,6 +4631,30 @@ static const struct bpf_func_proto
bpf_get_socket_cookie_sock_proto = {
.arg1_type = ARG_PTR_TO_CTX,
};
+BPF_CALL_1(bpf_get_socket_ptr_cookie_sleepable, struct sock *, sk)
+{
+ return sk ? sock_gen_cookie(sk) : 0;
+}
+
+const struct bpf_func_proto bpf_get_socket_ptr_cookie_sleepable_proto = {
+ .func = bpf_get_socket_ptr_cookie_sleepable,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
+};
+
+BPF_CALL_1(bpf_get_socket_ptr_cookie, struct sock *, sk)
+{
+ return sk ? __sock_gen_cookie(sk) : 0;
+}
+
+const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto = {
+ .func = bpf_get_socket_ptr_cookie,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
+};
+
BPF_CALL_1(bpf_get_socket_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx)
{
return __sock_gen_cookie(ctx->sk);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index ba59309f4d18..9ac66cf25959 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1667,6 +1667,13 @@ union bpf_attr {
* Return
* A 8-byte long unique number.
*
+ * u64 bpf_get_socket_cookie(void *sk)
+ * Description
+ * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
+ * *sk*, but gets socket from a BTF **struct sock**.
+ * Return
+ * A 8-byte long unique number.
+ *
* u32 bpf_get_socket_uid(struct sk_buff *skb)
* Return
* The owner UID of the socket associated to *skb*. If the socket
--
2.29.2.576.ga3fc446d84-goog
