27.05.2020, 19:43, "Eric Dumazet" [off-list ref]:

On 5/27/20 8:05 AM, Dmitry Yakunin wrote:

quoted

 This patch adds support of SO_KEEPALIVE flag and TCP related options
 to bpf_setsockopt() routine. This is helpful if we want to enable or tune
 TCP keepalive for applications which don't do it in the userspace code.
 In order to avoid copy-paste, common code from classic setsockopt was moved
 to auxiliary functions in the headers.

Please split this in two patches :
- one adding the helpers, a pure TCP patch.
- one for BPF additions.

Thanks for your comment.
I've split this into three patches (sock, tcp and bpf) and resent.

quoted

 Signed-off-by: Dmitry Yakunin [off-list ref]
 ---
  include/net/sock.h | 9 +++++++++
  include/net/tcp.h | 18 ++++++++++++++++++
  net/core/filter.c | 39 ++++++++++++++++++++++++++++++++++++++-
  net/core/sock.c | 9 ---------
  net/ipv4/tcp.c | 15 ++-------------
  5 files changed, 67 insertions(+), 23 deletions(-)

 diff --git a/include/net/sock.h b/include/net/sock.h
 index 3e8c6d4..ee35dea 100644
 --- a/include/net/sock.h
 +++ b/include/net/sock.h
 @@ -879,6 +879,15 @@ static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
          __clear_bit(flag, &sk->sk_flags);
  }

 +static inline void sock_valbool_flag(struct sock *sk, enum sock_flags bit,
 + int valbool)
 +{
 + if (valbool)
 + sock_set_flag(sk, bit);
 + else
 + sock_reset_flag(sk, bit);
 +}
 +
  static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
  {
          return test_bit(flag, &sk->sk_flags);
 diff --git a/include/net/tcp.h b/include/net/tcp.h
 index b681338..ae6a495 100644
 --- a/include/net/tcp.h
 +++ b/include/net/tcp.h
 @@ -1465,6 +1465,24 @@ static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp)
                            tcp_jiffies32 - tp->rcv_tstamp);
  }

 +/* val must be validated at the top level function */
 +static inline void keepalive_time_set(struct tcp_sock *tp, int val)
 +{
 + struct sock *sk = (struct sock *)tp;

We prefer the other way to avoid a cast unless really needed :

static inline tcp_keepalive_time_set(struct sock *sk, int val)
{
      stuct tcp_sock *tp = tcp_sk(sk);

quoted

 +
 + tp->keepalive_time = val * HZ;
 + if (sock_flag(sk, SOCK_KEEPOPEN) &&
 + !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
 + u32 elapsed = keepalive_time_elapsed(tp);
 +
 + if (tp->keepalive_time > elapsed)
 + elapsed = tp->keepalive_time - elapsed;
 + else
 + elapsed = 0;
 + inet_csk_reset_keepalive_timer(sk, elapsed);
 + }
 +}
 +
  static inline int tcp_fin_time(const struct sock *sk)
  {
          int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout;
 diff --git a/net/core/filter.c b/net/core/filter.c
 index a6fc234..1035e43 100644
 --- a/net/core/filter.c
 +++ b/net/core/filter.c
 @@ -4248,8 +4248,8 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = {
  static int _bpf_setsockopt(struct sock *sk, int level, int optname,
                             char *optval, int optlen, u32 flags)
  {
 + int val, valbool;
          int ret = 0;
 - int val;

          if (!sk_fullsock(sk))
                  return -EINVAL;
 @@ -4260,6 +4260,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
                  if (optlen != sizeof(int))
                          return -EINVAL;
                  val = *((int *)optval);
 + valbool = val ? 1 : 0;

                  /* Only some socketops are supported */
                  switch (optname) {
 @@ -4298,6 +4299,11 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
                                  sk_dst_reset(sk);
                          }
                          break;
 + case SO_KEEPALIVE:
 + if (sk->sk_prot->keepalive)
 + sk->sk_prot->keepalive(sk, valbool);
 + sock_valbool_flag(sk, SOCK_KEEPOPEN, valbool);
 + break;
                  default:
                          ret = -EINVAL;
                  }
 @@ -4358,6 +4364,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
                          ret = tcp_set_congestion_control(sk, name, false,
                                                           reinit, true);
                  } else {
 + struct inet_connection_sock *icsk = inet_csk(sk);
                          struct tcp_sock *tp = tcp_sk(sk);

                          if (optlen != sizeof(int))
 @@ -4386,6 +4393,36 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
                                  else
                                          tp->save_syn = val;
                                  break;
 + case TCP_KEEPIDLE:
 + if (val < 1 || val > MAX_TCP_KEEPIDLE)
 + ret = -EINVAL;
 + else
 + keepalive_time_set(tp, val);
 + break;
 + case TCP_KEEPINTVL:
 + if (val < 1 || val > MAX_TCP_KEEPINTVL)
 + ret = -EINVAL;
 + else
 + tp->keepalive_intvl = val * HZ;
 + break;
 + case TCP_KEEPCNT:
 + if (val < 1 || val > MAX_TCP_KEEPCNT)
 + ret = -EINVAL;
 + else
 + tp->keepalive_probes = val;
 + break;
 + case TCP_SYNCNT:
 + if (val < 1 || val > MAX_TCP_SYNCNT)
 + ret = -EINVAL;
 + else
 + icsk->icsk_syn_retries = val;
 + break;
 + case TCP_USER_TIMEOUT:
 + if (val < 0)
 + ret = -EINVAL;
 + else
 + icsk->icsk_user_timeout = val;
 + break;
                          default:
                                  ret = -EINVAL;
                          }
 diff --git a/net/core/sock.c b/net/core/sock.c
 index fd85e65..9836b01 100644
 --- a/net/core/sock.c
 +++ b/net/core/sock.c
 @@ -684,15 +684,6 @@ static int sock_getbindtodevice(struct sock *sk, char __user *optval,
          return ret;
  }

 -static inline void sock_valbool_flag(struct sock *sk, enum sock_flags bit,
 - int valbool)
 -{
 - if (valbool)
 - sock_set_flag(sk, bit);
 - else
 - sock_reset_flag(sk, bit);
 -}
 -
  bool sk_mc_loop(struct sock *sk)
  {
          if (dev_recursion_level())
 diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
 index 9700649..7b239e8 100644
 --- a/net/ipv4/tcp.c
 +++ b/net/ipv4/tcp.c
 @@ -3003,19 +3003,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
          case TCP_KEEPIDLE:
                  if (val < 1 || val > MAX_TCP_KEEPIDLE)
                          err = -EINVAL;
 - else {
 - tp->keepalive_time = val * HZ;
 - if (sock_flag(sk, SOCK_KEEPOPEN) &&
 - !((1 << sk->sk_state) &
 - (TCPF_CLOSE | TCPF_LISTEN))) {
 - u32 elapsed = keepalive_time_elapsed(tp);
 - if (tp->keepalive_time > elapsed)
 - elapsed = tp->keepalive_time - elapsed;
 - else
 - elapsed = 0;
 - inet_csk_reset_keepalive_timer(sk, elapsed);
 - }
 - }
 + else
 + keepalive_time_set(tp, val);
                  break;
          case TCP_KEEPINTVL:
                  if (val < 1 || val > MAX_TCP_KEEPINTVL)