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DTRACE_SCTP(4)		     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) proto-
     col 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::as-
     soc: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:%-5s\n", "CPU",
		       "LADDR", "LPORT", "RADDR", "RPORT");
	   }

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

	   sctp:::receive
	   {
		   printf(" %3d %16s:%-5d <- %16s:%-5d\n", 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    %-25s\n",
		       "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 -> %-25s\n", 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 -> %-25s\n", 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 ports 15.quarterly	  June 29, 2023 		  DTRACE_SCTP(4)

Want to link to this manual page? Use this URL:
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