On 1/12/25 3:37 AM, Jason Xing wrote:
Users can write the following code to enable the bpf extension:
bpf_setsockopt(skops, SOL_SOCKET, SK_BPF_CB_FLAGS, &flags, sizeof(flags));
Signed-off-by: Jason Xing <kerneljasonxing@xxxxxxxxx>
---
include/net/sock.h | 7 +++++++
include/uapi/linux/bpf.h | 8 ++++++++
net/core/filter.c | 25 +++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 1 +
4 files changed, 41 insertions(+)
diff --git a/include/net/sock.h b/include/net/sock.h
index ccf86c8a7a8a..f5447b4b78fd 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -303,6 +303,7 @@ struct sk_filter;
* @sk_stamp: time stamp of last packet received
* @sk_stamp_seq: lock for accessing sk_stamp on 32 bit architectures only
* @sk_tsflags: SO_TIMESTAMPING flags
+ * @sk_bpf_cb_flags: used for bpf_setsockopt
* @sk_use_task_frag: allow sk_page_frag() to use current->task_frag.
* Sockets that can be used under memory reclaim should
* set this to false.
@@ -445,6 +446,12 @@ struct sock {
u32 sk_reserved_mem;
int sk_forward_alloc;
u32 sk_tsflags;
+#ifdef CONFIG_BPF_SYSCALL
The CONFIG_BPF is used instead in the existing "u8 bpf_sock_ops_cb_flags;" in
tcp_sock. afaik, CONFIG_BPF is selected by CONFIG_NET. It is why the test bot
fails when CONFIG_BPF_SYSCALL is used here but not with the existing
bpf_sock_ops_cb_flags. Considering CONFIG_BPF is also mostly useless here
because of CONFIG_NET, I would remove this ifdef usage altogether. If there is
really a need to distinguish CONFIG_BPF_SYSCALL is enabled or not, this can be
improved together with the existing bpf_sock_ops_cb_flags.
+#define SK_BPF_CB_FLAG_TEST(SK, FLAG) ((SK)->sk_bpf_cb_flags & (FLAG))
+ u32 sk_bpf_cb_flags;
+#else
+#define SK_BPF_CB_FLAG_TEST(SK, FLAG) 0
+#endif
__cacheline_group_end(sock_write_rxtx);
__cacheline_group_begin(sock_write_tx);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 4162afc6b5d0..e629e09b0b31 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6903,6 +6903,13 @@ enum {
BPF_SOCK_OPS_ALL_CB_FLAGS = 0x7F,
};
+/* Definitions for bpf_sk_cb_flags */
+enum {
+ SK_BPF_CB_TX_TIMESTAMPING = 1<<0,
+ SK_BPF_CB_MASK = (SK_BPF_CB_TX_TIMESTAMPING - 1) |
+ SK_BPF_CB_TX_TIMESTAMPING
+};
+
/* List of known BPF sock_ops operators.
* New entries can only be added at the end
*/
@@ -7081,6 +7088,7 @@ enum {
TCP_BPF_SYN_IP = 1006, /* Copy the IP[46] and TCP header */
TCP_BPF_SYN_MAC = 1007, /* Copy the MAC, IP[46], and TCP header */
TCP_BPF_SOCK_OPS_CB_FLAGS = 1008, /* Get or Set TCP sock ops flags */
+ SK_BPF_CB_FLAGS = 1009, /* Used to set socket bpf flags */
};
enum {
diff --git a/net/core/filter.c b/net/core/filter.c
index b957cf57299e..c6dd2d2e44c8 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5222,6 +5222,23 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = {
.arg1_type = ARG_PTR_TO_CTX,
};
+static int sk_bpf_set_cb_flags(struct sock *sk, char *optval, bool getopt)
+{
+ u32 sk_bpf_cb_flags;
+
+ if (getopt)
I may have this in my earlier sample code? This is probably because of my
laziness for a quick example. getopt should also be supported, similar to the
existing TCP_BPF_SOCK_OPS_CB_FLAGS.
+ return -EINVAL;
+
+ sk_bpf_cb_flags = *(u32 *)optval;
+
+ if (sk_bpf_cb_flags & ~SK_BPF_CB_MASK)
+ return -EINVAL;
+
+ sk->sk_bpf_cb_flags = sk_bpf_cb_flags;
+
+ return 0;
+}
+
static int sol_socket_sockopt(struct sock *sk, int optname,
char *optval, int *optlen,
bool getopt)
@@ -5238,6 +5255,7 @@ static int sol_socket_sockopt(struct sock *sk, int optname,
case SO_MAX_PACING_RATE:
case SO_BINDTOIFINDEX:
case SO_TXREHASH:
+ case SK_BPF_CB_FLAGS:
if (*optlen != sizeof(int))
return -EINVAL;
break;
@@ -5247,6 +5265,13 @@ static int sol_socket_sockopt(struct sock *sk, int optname,
return -EINVAL;
}
+ if (optname == SK_BPF_CB_FLAGS)
+#ifdef CONFIG_BPF_SYSCALL
+ return sk_bpf_set_cb_flags(sk, optval, getopt);
+#else
+ return -EINVAL;
+#endif
+
if (getopt) {
if (optname == SO_BINDTODEVICE)
return -EINVAL;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 4162afc6b5d0..6b0a5b787b12 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -7081,6 +7081,7 @@ enum {
TCP_BPF_SYN_IP = 1006, /* Copy the IP[46] and TCP header */
TCP_BPF_SYN_MAC = 1007, /* Copy the MAC, IP[46], and TCP header */
TCP_BPF_SOCK_OPS_CB_FLAGS = 1008, /* Get or Set TCP sock ops flags */
+ SK_BPF_CB_FLAGS = 1009, /* Used to set socket bpf flags */
};
enum {
