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>.