Re: [PATCH net-next v2 02/12] net-timestamp: open gate for bpf_setsockopt

On Tue, Oct 15, 2024 at 9:34 AM Willem de Bruijn
[off-list ref] wrote:

Jason Xing wrote:

quoted

From: Jason Xing <kernelxing@tencent.com>

For now, we support bpf_setsockopt only TX timestamps flags. Users
can use something like this in bpf program to turn on the feature:

flags = SOF_TIMESTAMPING_TX_SCHED;
bpf_setsockopt(skops, SOL_SOCKET, SO_TIMESTAMPING, &flags, sizeof(flags));

Later, I will support each Tx flags one by one based on this.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 include/net/sock.h |  2 ++
 net/core/filter.c  | 27 +++++++++++++++++++++++++++
 net/core/sock.c    | 35 ++++++++++++++++++++++++-----------
 3 files changed, 53 insertions(+), 11 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 8cf278c957b3..66ecd78f1dfe 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h

@@ -2890,6 +2890,8 @@ void sock_def_readable(struct sock *sk);

 int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk);
 void sock_set_timestamp(struct sock *sk, int optname, bool valbool);
+int sock_get_timestamping(struct so_timestamping *timestamping,
+                       sockptr_t optval, unsigned int optlen);
 int sock_set_timestamping(struct sock *sk, int optname,
                        struct so_timestamping timestamping);

diff --git a/net/core/filter.c b/net/core/filter.c
index bd0d08bf76bb..996426095bd9 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c

@@ -5204,10 +5204,30 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = {
      .arg1_type      = ARG_PTR_TO_CTX,
 };

+static int bpf_sock_set_timestamping(struct sock *sk,
+                                  struct so_timestamping *timestamping)
+{
+     u32 flags = timestamping->flags;
+
+     if (flags & ~SOF_TIMESTAMPING_MASK)
+             return -EINVAL;
+
+     if (!(flags & (SOF_TIMESTAMPING_TX_SCHED | SOF_TIMESTAMPING_TX_SOFTWARE |
+           SOF_TIMESTAMPING_TX_ACK)))
+             return -EINVAL;
+
+     WRITE_ONCE(sk->sk_tsflags[BPFPROG_TS_REQUESTOR], flags);
+
+     return 0;
+}
+
 static int sol_socket_sockopt(struct sock *sk, int optname,
                            char *optval, int *optlen,
                            bool getopt)
 {
+     struct so_timestamping ts;
+     int ret = 0;
+
      switch (optname) {
      case SO_REUSEADDR:
      case SO_SNDBUF:

@@ -5225,6 +5245,13 @@ static int sol_socket_sockopt(struct sock *sk, int optname,
              break;
      case SO_BINDTODEVICE:
              break;
+     case SO_TIMESTAMPING_NEW:
+     case SO_TIMESTAMPING_OLD:
+             ret = sock_get_timestamping(&ts, KERNEL_SOCKPTR(optval),
+                                         *optlen);
+             if (!ret)
+                     ret = bpf_sock_set_timestamping(sk, &ts);
+             return ret;
      default:
              return -EINVAL;
      }

diff --git a/net/core/sock.c b/net/core/sock.c
index 52c8c5a5ba27..a6e0d51a5f72 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c

@@ -894,6 +894,27 @@ static int sock_timestamping_bind_phc(struct sock *sk, int phc_index)
      return 0;
 }

+int sock_get_timestamping(struct so_timestamping *timestamping,
+                       sockptr_t optval, unsigned int optlen)
+{
+     int val;
+
+     if (copy_from_sockptr(&val, optval, sizeof(val)))
+             return -EFAULT;

Ideally don't read this again.

If you do, then move it in the else clause.

Thanks, I will do that.