NAME

     dtrace_udplite — a DTrace provider for tracing events related to the UDP-Lite protocol

SYNOPSIS

     udplite:::receive(pktinfo_t *, csinfo_t *, ipinfo_t *, udplitesinfo_t *, udpliteinfo_t *);

     udplite:::send(pktinfo_t *, csinfo_t *, ipinfo_t *, udplitesinfo_t *, udpliteinfo_t *);

DESCRIPTION

     The DTrace udplite provider allows users to trace events in the udplite(4) protocol
     implementation.  The udplite:::send() probe fires whenever the kernel prepares to transmit a
     UDP-Lite packet, and the udplite:::receive() probe fires whenever the kernel receives a UDP-
     Lite packet, unless the UDP-Lite header is incomplete, the destination port is 0, the length
     field is invalid, or the checksum is wrong.  The arguments to these probes can be used to
     obtain detailed information about the IP and UDP-Lite headers of the corresponding packet.

ARGUMENTS

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

           uintptr_t cs_addr  Always set to 0.

           uint64_t cs_cid    A pointer to the struct inpcb for this packet, or NULL.

           pid_t cs_pid       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 udplitesinfo_t argument contains the state of the UDP-Lite connection associated with
     the packet.  Its fields are:

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

           uint16_t udplites_lport  Local UDP-Lite port.

           uint16_t udplites_rport  Remote UDP-Lite port.

           string udplites_laddr    Local IPv4 or IPv6 address.

           string udplites_raddr    Remote IPv4 or IPv6 address.

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

           uint16_t udplite_sport          Source UDP-Lite port.

           uint16_t udplite_dport          Destination UDP-Lite port.

           uint16_t udplite_coverage       Checksum coverage of the UDP-Lite header, in bytes, or
                                           0 for full coverage.

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

           struct udplitehdr *udplite_hdr  A pointer to the raw UDP-Lite header.

FILES

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

EXAMPLES

     The following script counts transmitted packets by destination port.

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

     This script will print some details of each UDP-Lite 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 %6s\n", "DELTA(us)", "SOURCE",
                       "DEST", "COV");
                   last = timestamp;
           }

           udplite:::send
           {
                   this->elapsed = (timestamp - last) / 1000;
                   self->dest = strjoin(strjoin(args[2]->ip_daddr, ":"),
                        lltostr(args[4]->udplite_dport));
                   printf(" %10d %30s:%-5d -> %-36s %6d\n", this->elapsed,
                       args[2]->ip_saddr, args[4]->udplite_sport,
                       self->dest, args[4]->udplite_coverage);
                   last = timestamp;
           }

           udplite:::receive
           {
                   this->elapsed = (timestamp - last) / 1000;
                   self->dest = strjoin(strjoin(args[2]->ip_saddr, ":"),
                        lltostr(args[4]->udplite_sport));
                   printf(" %10d %30s:%-5d <- %-36s %6d\n", this->elapsed,
                       args[2]->ip_daddr, args[4]->udplite_dport,
                       self->dest, args[4]->udplite_coverage);
                   last = timestamp;
           }

SEE ALSO

     dtrace(1), dtrace_ip(4), dtrace_sctp(4), dtrace_tcp(4), dtrace_udp(4), udplite(4), SDT(9)

HISTORY

     The udplite provider first appeared in FreeBSD 12.0.

AUTHORS

     This manual page was written by Mark Johnston <markj@FreeBSD.org> and
     Michael Tuexen <tuexen@FreeBSD.org>.