user/sven/linux.git/include/uapi/linux/tcp.h, branch v5.4.269

tcp: Add snd_wnd to TCP_INFO

2019-09-16T14:26:11Z

Neal Cardwell mentioned that snd_wnd would be useful for diagnosing TCP performance problems -- > (1) Usually when we're diagnosing TCP performance problems, we do so > from the sender, since the sender makes most of the > performance-critical decisions (cwnd, pacing, TSO size, TSQ, etc). > From the sender-side the thing that would be most useful is to see > tp->snd_wnd, the receive window that the receiver has advertised to > the sender. This serves the purpose of adding an additional __u32 to avoid the would-be hole caused by the addition of the tcpi_rcvi_ooopack field. Signed-off-by: Thomas Higdon Acked-by: Yuchung Cheng Acked-by: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller

tcp: Add TCP_INFO counter for packets received out-of-order

2019-09-16T14:26:11Z

For receive-heavy cases on the server-side, we want to track the connection quality for individual client IPs. This counter, similar to the existing system-wide TCPOFOQueue counter in /proc/net/netstat, tracks out-of-order packet reception. By providing this counter in TCP_INFO, it will allow understanding to what degree receive-heavy sockets are experiencing out-of-order delivery and packet drops indicating congestion. Please note that this is similar to the counter in NetBSD TCP_INFO, and has the same name. Also note that we avoid increasing the size of the tcp_sock struct by taking advantage of a hole. Signed-off-by: Thomas Higdon Acked-by: Neal Cardwell Signed-off-by: David S. Miller

tcp: add optional per socket transmit delay

2019-06-12T20:05:43Z

Adding delays to TCP flows is crucial for studying behavior of TCP stacks, including congestion control modules. Linux offers netem module, but it has unpractical constraints : - Need root access to change qdisc - Hard to setup on egress if combined with non trivial qdisc like FQ - Single delay for all flows. EDT (Earliest Departure Time) adoption in TCP stack allows us to enable a per socket delay at a very small cost. Networking tools can now establish thousands of flows, each of them with a different delay, simulating real world conditions. This requires FQ packet scheduler or a EDT-enabled NIC. This patchs adds TCP_TX_DELAY socket option, to set a delay in usec units. unsigned int tx_delay = 10000; /* 10 msec */ setsockopt(fd, SOL_TCP, TCP_TX_DELAY, &tx_delay, sizeof(tx_delay)); Note that FQ packet scheduler limits might need some tweaking : man tc-fq PARAMETERS limit Hard limit on the real queue size. When this limit is reached, new packets are dropped. If the value is lowered, packets are dropped so that the new limit is met. Default is 10000 packets. flow_limit Hard limit on the maximum number of packets queued per flow. Default value is 100. Use of TCP_TX_DELAY option will increase number of skbs in FQ qdisc, so packets would be dropped if any of the previous limit is hit. Use of a jump label makes this support runtime-free, for hosts never using the option. Also note that TSQ (TCP Small Queues) limits are slightly changed with this patch : we need to account that skbs artificially delayed wont stop us providind more skbs to feed the pipe (netem uses skb_orphan_partial() for this purpose, but FQ can not use this trick) Because of that, using big delays might very well trigger old bugs in TSO auto defer logic and/or sndbuf limited detection. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: add documentation for tcp_ca_state

2019-03-24T01:50:05Z

Add documentation to the tcp_ca_state enum, since this enum is exposed in uapi. Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Cc: Sowmini Varadhan Acked-by: Sowmini Varadhan Signed-off-by: David S. Miller

tcp: add SRTT to SCM_TIMESTAMPING_OPT_STATS

2018-11-18T04:34:36Z

Add TCP_NLA_SRTT to SCM_TIMESTAMPING_OPT_STATS that reports the smoothed round trip time in microseconds (tcp_sock.srtt_us >> 3). Signed-off-by: Yousuk Seung Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Acked-by: Neal Cardwell Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

tcp: add stat of data packet reordering events

2018-08-01T16:56:10Z

Introduce a new TCP stats to record the number of reordering events seen and expose it in both tcp_info (TCP_INFO) and opt_stats (SOF_TIMESTAMPING_OPT_STATS). Application can use this stats to track the frequency of the reordering events in addition to the existing reordering stats which tracks the magnitude of the latest reordering event. Note: this new stats tracks reordering events triggered by ACKs, which could often be fewer than the actual number of packets being delivered out-of-order. Signed-off-by: Wei Wang Signed-off-by: Eric Dumazet Acked-by: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

tcp: add dsack blocks received stats

2018-08-01T16:56:10Z

Introduce a new TCP stat to record the number of DSACK blocks received (RFC4989 tcpEStatsStackDSACKDups) and expose it in both tcp_info (TCP_INFO) and opt_stats (SOF_TIMESTAMPING_OPT_STATS). Signed-off-by: Wei Wang Signed-off-by: Eric Dumazet Acked-by: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

tcp: add data bytes retransmitted stats

2018-08-01T16:56:10Z

Introduce a new TCP stat to record the number of bytes retransmitted (RFC4898 tcpEStatsPerfOctetsRetrans) and expose it in both tcp_info (TCP_INFO) and opt_stats (SOF_TIMESTAMPING_OPT_STATS). Signed-off-by: Wei Wang Signed-off-by: Eric Dumazet Acked-by: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

tcp: add data bytes sent stats

2018-08-01T16:56:10Z

Introduce a new TCP stat to record the number of bytes sent (RFC4898 tcpEStatsPerfHCDataOctetsOut) and expose it in both tcp_info (TCP_INFO) and opt_stats (SOF_TIMESTAMPING_OPT_STATS). Signed-off-by: Wei Wang Signed-off-by: Eric Dumazet Acked-by: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

tcp: Fix broken repair socket window probe patch

2018-07-16T21:06:44Z

Correct previous bad attempt at allowing sockets to come out of TCP repair without sending window probes. To avoid changing size of the repair variable in struct tcp_sock, this lets the decision for sending probes or not to be made when coming out of repair by introducing two ways to turn it off. v2: * Remove erroneous comment; defines now make behavior clear Fixes: 70b7ff130224 ("tcp: allow user to create repair socket without window probes") Signed-off-by: Stefan Baranoff Signed-off-by: Eric Dumazet Acked-by: Andrei Vagin Signed-off-by: David S. Miller