diff options
| -rw-r--r-- | Documentation/networking/timestamping.rst | 32 | ||||
| -rw-r--r-- | include/net/sock.h | 6 | ||||
| -rw-r--r-- | include/uapi/linux/net_tstamp.h | 3 | ||||
| -rw-r--r-- | net/core/sock.c | 9 | ||||
| -rw-r--r-- | net/ethtool/common.c | 1 |
5 files changed, 45 insertions, 6 deletions
diff --git a/Documentation/networking/timestamping.rst b/Documentation/networking/timestamping.rst index be4eb1242057..f17c01834a12 100644 --- a/Documentation/networking/timestamping.rst +++ b/Documentation/networking/timestamping.rst @@ -179,7 +179,8 @@ SOF_TIMESTAMPING_OPT_ID: identifier and returns that along with the timestamp. The identifier is derived from a per-socket u32 counter (that wraps). For datagram sockets, the counter increments with each sent packet. For stream - sockets, it increments with every byte. + sockets, it increments with every byte. For stream sockets, also set + SOF_TIMESTAMPING_OPT_ID_TCP, see the section below. The counter starts at zero. It is initialized the first time that the socket option is enabled. It is reset each time the option is @@ -192,6 +193,35 @@ SOF_TIMESTAMPING_OPT_ID: among all possibly concurrently outstanding timestamp requests for that socket. +SOF_TIMESTAMPING_OPT_ID_TCP: + Pass this modifier along with SOF_TIMESTAMPING_OPT_ID for new TCP + timestamping applications. SOF_TIMESTAMPING_OPT_ID defines how the + counter increments for stream sockets, but its starting point is + not entirely trivial. This option fixes that. + + For stream sockets, if SOF_TIMESTAMPING_OPT_ID is set, this should + always be set too. On datagram sockets the option has no effect. + + A reasonable expectation is that the counter is reset to zero with + the system call, so that a subsequent write() of N bytes generates + a timestamp with counter N-1. SOF_TIMESTAMPING_OPT_ID_TCP + implements this behavior under all conditions. + + SOF_TIMESTAMPING_OPT_ID without modifier often reports the same, + especially when the socket option is set when no data is in + transmission. If data is being transmitted, it may be off by the + length of the output queue (SIOCOUTQ). + + The difference is due to being based on snd_una versus write_seq. + snd_una is the offset in the stream acknowledged by the peer. This + depends on factors outside of process control, such as network RTT. + write_seq is the last byte written by the process. This offset is + not affected by external inputs. + + The difference is subtle and unlikely to be noticed when configured + at initial socket creation, when no data is queued or sent. But + SOF_TIMESTAMPING_OPT_ID_TCP behavior is more robust regardless of + when the socket option is set. SOF_TIMESTAMPING_OPT_CMSG: Support recv() cmsg for all timestamped packets. Control messages diff --git a/include/net/sock.h b/include/net/sock.h index 6d207e7c4ad0..ecea3dcc2217 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -503,10 +503,10 @@ struct sock { #if BITS_PER_LONG==32 seqlock_t sk_stamp_seq; #endif - u16 sk_tsflags; - u8 sk_shutdown; atomic_t sk_tskey; atomic_t sk_zckey; + u32 sk_tsflags; + u8 sk_shutdown; u8 sk_clockid; u8 sk_txtime_deadline_mode : 1, @@ -1899,7 +1899,7 @@ static inline void sock_replace_proto(struct sock *sk, struct proto *proto) struct sockcm_cookie { u64 transmit_time; u32 mark; - u16 tsflags; + u32 tsflags; }; static inline void sockcm_init(struct sockcm_cookie *sockc, diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h index 55501e5e7ac8..a2c66b3d7f0f 100644 --- a/include/uapi/linux/net_tstamp.h +++ b/include/uapi/linux/net_tstamp.h @@ -31,8 +31,9 @@ enum { SOF_TIMESTAMPING_OPT_PKTINFO = (1<<13), SOF_TIMESTAMPING_OPT_TX_SWHW = (1<<14), SOF_TIMESTAMPING_BIND_PHC = (1 << 15), + SOF_TIMESTAMPING_OPT_ID_TCP = (1 << 16), - SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_BIND_PHC, + SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_ID_TCP, SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) | SOF_TIMESTAMPING_LAST }; diff --git a/net/core/sock.c b/net/core/sock.c index 4571914a4aa8..b0ab841e0aed 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -901,13 +901,20 @@ int sock_set_timestamping(struct sock *sk, int optname, if (val & ~SOF_TIMESTAMPING_MASK) return -EINVAL; + if (val & SOF_TIMESTAMPING_OPT_ID_TCP && + !(val & SOF_TIMESTAMPING_OPT_ID)) + return -EINVAL; + if (val & SOF_TIMESTAMPING_OPT_ID && !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)) { if (sk_is_tcp(sk)) { if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) return -EINVAL; - atomic_set(&sk->sk_tskey, tcp_sk(sk)->snd_una); + if (val & SOF_TIMESTAMPING_OPT_ID_TCP) + atomic_set(&sk->sk_tskey, tcp_sk(sk)->write_seq); + else + atomic_set(&sk->sk_tskey, tcp_sk(sk)->snd_una); } else { atomic_set(&sk->sk_tskey, 0); } diff --git a/net/ethtool/common.c b/net/ethtool/common.c index 21cfe8557205..6f399afc2ff2 100644 --- a/net/ethtool/common.c +++ b/net/ethtool/common.c @@ -417,6 +417,7 @@ const char sof_timestamping_names[][ETH_GSTRING_LEN] = { [const_ilog2(SOF_TIMESTAMPING_OPT_PKTINFO)] = "option-pktinfo", [const_ilog2(SOF_TIMESTAMPING_OPT_TX_SWHW)] = "option-tx-swhw", [const_ilog2(SOF_TIMESTAMPING_BIND_PHC)] = "bind-phc", + [const_ilog2(SOF_TIMESTAMPING_OPT_ID_TCP)] = "option-id-tcp", }; static_assert(ARRAY_SIZE(sof_timestamping_names) == __SOF_TIMESTAMPING_CNT); |