DTRACE-UDP(4)	       FreeBSD Kernel Interfaces Manual 	 DTRACE-UDP(4)

NAME
     dtrace-udp – a DTrace provider for tracing events related to the UDP
     protocol

SYNOPSIS
     udp:::receive(pktinfo_t *, csinfo_t *, ipinfo_t *, udpsinfo_t *,
	 udpinfo_t *);

     udp:::send(pktinfo_t *, csinfo_t *, ipinfo_t *, udpsinfo_t *,
	 udpinfo_t *);

DESCRIPTION
     The DTrace udp provider allows users to trace events in the udp(4)
     protocol implementation.  The udp:::send() probe fires whenever the
     kernel prepares to transmit a UDP packet, and the udp:::receive() probe
     fires whenever the kernel receives a UDP packet.  The arguments to these
     probes can be used to obtain detailed information about the IP and UDP
     headers of the corresponding packet.

ARGUMENTS
     The pktinfo_t argument is currently unused and is included for
     compatibility with other implementations of this provider.  Its fields
     are:

	   uintptr_t pkt_addr  Always set to 0.

     The csinfo_t argument is currently unused and is included for
     compatibility with other implementations of this provider.  Its fields
     are:

	   uintptr_t cs_addr  Always set to 0.

     The ipinfo_t argument contains IP fields common to both IPv4 and IPv6
     packets.  Its fields are:

	   uint8_t ip_ver	IP version of the packet, 4 for IPv4 packets
				and 6 for IPv6 packets.

	   uint32_t ip_plength	IP payload size.  This does not include the
				size of the IP header or IPv6 option headers.

	   string ip_saddr	IP source address.

	   string ip_daddr	IP destination address.

     The udpsinfo_t argument contains the state of the UDP connection
     associated with the packet.  Its fields are:

	   uintptr_t udps_addr	Pointer to the struct inpcb containing the IP
				state for the associated socket.

	   uint16_t udps_lport	Local UDP port.

	   uint16_t udps_rport	Remote UDP port.

	   string udps_laddr	Local IPv4 or IPv6 address.

	   string udps_raddr	Remote IPv4 or IPv6 address.

     The udpinfo_t argument is the raw UDP header of the packet, with all
     fields in host order.  Its fields are:

	   uint16_t udp_sport	   Source UDP port.

	   uint16_t udp_dport	   Destination UDP port.

	   uint16_t udp_length	   Length of the UDP header and payload, in
				   bytes.

	   uint16_t udp_checksum   A checksum of the UDP header and payload,
				   or 0 if no checksum was calculated.

	   struct udphdr *udp_hdr  A pointer to the raw UDP header.

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

EXAMPLES
     The following script counts transmitted packets by destination port.

	   udp:::send
	   {
		   @num[args[4]->udp_dport] = count();
	   }

     This script will print some details of each UDP packet as it is sent or
     received by the kernel:

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

	   dtrace:::BEGIN
	   {
		   printf(" %10s %36s	 %-36s %6s0, "DELTA(us)", "SOURCE",
		       "DEST", "BYTES");
		   last = timestamp;
	   }

	   udp:::send
	   {
		   this->elapsed = (timestamp - last) / 1000;
		   self->dest = strjoin(strjoin(args[2]->ip_daddr, ":"),
			lltostr(args[4]->udp_dport));
		   printf(" %10d %30s:%-5d -> %-36s %6d0, this->elapsed,
		       args[2]->ip_saddr, args[4]->udp_sport,
		       self->dest, args[4]->udp_length);
		   last = timestamp;
	   }

	   udp:::receive
	   {
		   this->elapsed = (timestamp - last) / 1000;
		   self->dest = strjoin(strjoin(args[2]->ip_saddr, ":"),
			lltostr(args[4]->udp_sport));
		   printf(" %10d %30s:%-5d <- %-36s %6d0, this->elapsed,
		       args[2]->ip_daddr, args[4]->udp_dport,
		       self->dest, args[4]->udp_length);
		   last = timestamp;
	   }

COMPATIBILITY
     This provider is compatible with the udp providers found in Solaris and
     Darwin.

SEE ALSO
     dtrace(1), dtrace-ip(4), dtrace-tcp(4), udp(4), SDT(9)

HISTORY
     The udp provider first appeared in FreeBSD 10.0.

AUTHORS
     This manual page was written by Mark Johnston <markj@FreeBSD.org>.

FreeBSD 11.0-CURRENT	       February 27, 2014	  FreeBSD 11.0-CURRENT