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>.

Debian                                           August 22, 2018                                  DTRACE_SCTP(4)