DTRACE_SCTP(4)         FreeBSD Kernel Interfaces Manual         DTRACE_SCTP(4)

NAME
     dtrace_sctp - a DTrace provider for tracing events related to the sctp(4)
     protocol

SYNOPSIS
     sctp:cwnd::init(uint32_t, uint32_t, uintptr_t, int, int);

     sctp:cwnd::ack(uint32_t, uint32_t, uintptr_t, int, int);

     sctp:cwnd::rttvar(uint64_t, uint64_t, uint64_t, uint64_t, uint64_t);

     sctp:cwnd::rttstep(uint64_t, uint64_t, uint64_t, uint64_t, uint64_t);

     sctp:cwnd::fr(uint32_t, uint32_t, uintptr_t, int, int);

     sctp:cwnd::to(uint32_t, uint32_t, uintptr_t, int, int);

     sctp:cwnd::bl(uint32_t, uint32_t, uintptr_t, int, int);

     sctp:cwnd::ecn(uint32_t, uint32_t, uintptr_t, int, int);

     sctp:cwnd::pd(uint32_t, uint32_t, uintptr_t, int, int);

     sctp:rwnd:assoc:val(uint32_t, uint32_t, int, int);

     sctp:flightsize:net:val(uint32_t, uint32_t, uintptr_t, int, int);

     sctp:flightsize:assoc:val(uint32_t, uint32_t, int, int);

     sctp:::receive(pktinfo_t *, csinfo_t *, ipinfo_t *, sctpsinfo_t *,
         sctpinfo_t *);

     sctp:::send(pktinfo_t *, csinfo_t *, ipinfo_t *, sctpsinfo_t *,
         sctpinfo_t *);

     sctp:::state-change(void *, csinfo_t *, void *, sctpsinfo_t *, void *,
         sctplsinfo_t *);

DESCRIPTION
     The DTrace sctp provider allows users to trace events in the sctp(4)
     protocol implementation.  This provider is similar to the dtrace_ip(4)
     and dtrace_udp(4) providers, but additionally contains probes
     corresponding to protocol events at a level higher than packet reception
     and transmission.

     The sctp:cwnd::() probes track changes in the congestion window on a
     netp.  The sctp:rwnd::() probes track changes in the receiver window for
     an assoc.  The sctp:flightsize:net:val() probe tracks changes in the
     flight size on a net or assoc and the sctp:flightsize:assoc:val() probe
     provides the total flight version.

     The arguments of all sctp probes except for sctp:cwnd::rtt*() and
     sctp::assoc:val() are the Vtag for this end, the port number of the local
     side, the pointer to struct sctp_nets *changing, the old value of the
     cwnd, and the new value of the cwnd.

     The arguments of sctp:::val() are similar to the above except the fourth
     argument is the up/down amount.

     The sctp:cwnd::rtt*() probe arguments are a bitmap of Vtag << 32 |
     localport << 16 | remoteport, a bitmap of obw | nbw, a bitmap of bwrtt |
     newrtt, flight, and a bitmap of (cwnd << 32) | point << 16 | retval(0/1).

     The sctp:cwnd::init() probe fires when a remotely-initiated active SCTP
     open succeeds.  At this point the new connection is in the ESTABLISHED
     state, and the probe arguments expose the headers associated with the
     final ACK of the four-way handshake.

     The sctp:::send() and sctp:::receive() probes fire when the host sends or
     receives an SCTP packet, respectively.  As with the dtrace_udp(4)
     provider, sctp probes fire only for packets sent by or to the local host;
     forwarded packets are handled in the IP layer and are only visible to the
     dtrace_ip(4) provider.

     The sctp:::state-change() probe fires upon local SCTP association state
     transitions.  Its first, third and fifth arguments are currently always
     NULL.  Its last argument describes the from-state in the transition, and
     the to-state can be obtained from args[3]->sctps_state.

FILES
     /usr/lib/dtrace/sctp.d  DTrace type and translator definitions for the
                             sctp provider.

EXAMPLES
     A script that logs SCTP packets in real time:

           #pragma D option quiet
           #pragma D option switchrate=10hz

           dtrace:::BEGIN
           {
                   printf(" %3s %15s:%-5s      %15s:%-5s0, "CPU",
                       "LADDR", "LPORT", "RADDR", "RPORT");
           }

           sctp:::send
           {
                   printf(" %3d %16s:%-5d -> %16s:%-5d0, cpu,
                       args[2]->ip_saddr, args[4]->sctp_sport,
                       args[2]->ip_daddr, args[4]->sctp_dport);
           }

           sctp:::receive
           {
                   printf(" %3d %16s:%-5d <- %16s:%-5d0, cpu,
                       args[2]->ip_daddr, args[4]->sctp_dport,
                       args[2]->ip_saddr, args[4]->sctp_sport);
           }
     A script that logs SCTP association state changes as they occur:

           #pragma D option quiet
           #pragma D option switchrate=10

           int last[int];

           dtrace:::BEGIN
           {
                   printf(" %3s %12s  %-25s    %-25s0,
                       "CPU", "DELTA(us)", "OLD", "NEW");
           }

           sctp:::state-change
           / last[args[1]->cs_cid] /
           {
                   this->elapsed = (timestamp - last[args[1]->cs_cid]) / 1000;
                   printf(" %3d %12d  %-25s -> %-25s0, cpu, this->elapsed,
                       sctp_state_string[args[5]->sctps_state],
                       sctp_state_string[args[3]->sctps_state]);
                   last[args[1]->cs_cid] = timestamp;
           }

           sctp:::state-change
           / last[args[1]->cs_cid] == 0 /
           {
                   printf(" %3d %12s  %-25s -> %-25s0, cpu, "-",
                       sctp_state_string[args[5]->sctps_state],
                       sctp_state_string[args[3]->sctps_state]);
                   last[args[1]->cs_cid] = timestamp;
           }

COMPATIBILITY
     The sctp:::send(), sctp:::receive(), and sctp:::state-change() probes are
     compatible with the sctp provider in Solaris.  All other probes are only
     available in FreeBSD.

SEE ALSO
     dtrace(1), dtrace_ip(4), dtrace_udp(4), dtrace_udplite(4), sctp(4),
     SDT(9)

AUTHORS
     This manual page was written by Devin Teske <dteske@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6         August 22, 2018        FreeBSD 13.1-RELEASE-p6