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dtrace_ip — a DTrace provider for tracing events related to the IPv4 and IPv6 protocols
Contents
Arguments
The pktinfo_t argument is currently unimplemented and is included for compatibility with other
implementations of this provider. Its fields are:
uintptr_tpkt_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_tcs_addr Always set to 0.
uint64_tcs_cid A pointer to the structinpcb for this packet, or NULL.
pid_tcs_pid Always set to 0.
The ipinfo_t argument contains IP fields common to both IPv4 and IPv6 packets. Its fields are:
uint8_tip_ver IP version of the packet, 4 for IPv4 packets and 6 for IPv6 packets.
uint32_tip_plength IP payload size. This does not include the size of the IP header or IPv6
option headers.
stringip_saddr IP source address.
stringip_daddr IP destination address.
The ifinfo_t argument describes the outgoing and incoming interfaces for the packet in the ip:::send()
and ip:::receive() probes respectively. Its fields are:
stringif_name The interface name.
int8_tif_local A boolean value indicating whether or not the interface is a loopback interface.
uintptr_tif_addr A pointer to the structifnet which describes the interface. See the ifnet(9)
manual page.
The ipv4info_t argument contains the fields of the IP header for IPv4 packets. This argument is NULL for
IPv6 packets. DTrace scripts should use the ip_ver() field in the ipinfo_t argument to determine whether
to use this argument. Its fields are:
uint8_tipv4_ver IP version. This will always be 4 for IPv4 packets.
uint8_tipv4_ihl The IP header length, including options, in 32-bit words.
uint8_tipv4_tos IP type of service field.
uint16_tipv4_length The total packet length, including the header, in bytes.
uint16_tipv4_ident Identification field.
uint8_tipv4_flags The IP flags.
uint16_tipv4_offset The fragment offset of the packet.
uint8_tipv4_ttl Time to live field.
uint8_tipv4_protocol Next-level protocol ID.
stringipv4_protostr A string containing the name of the encapsulated protocol. The protocol
strings are defined in the protocol array in /usr/lib/dtrace/ip.duint16_tipv4_checksum The IP checksum.
ipaddr_tipv4_src IPv4 source address.
ipaddr_tipv4_dst IPv4 destination address.
stringipv4_saddr A string representation of the source address.
stringipv4_daddr A string representation of the destination address.
ipha_t*ipv4_hdr A pointer to the raw IPv4 header.
The ipv6info_t argument contains the fields of the IP header for IPv6 packets. Its fields are not set
for IPv4 packets; as with the ipv4info_t argument, the ip_ver() field should be used to determine whether
this argument is valid. Its fields are:
uint8_tipv6_ver IP version. This will always be 6 for IPv6 packets.
uint8_tipv6_tclass The traffic class, used to set the differentiated services codepoint and
extended congestion notification flags.
uint32_tipv6_flow The flow label of the packet.
uint16_tipv6_plen The IP payload size, including extension headers, in bytes.
uint8_tipv6_nexthdr An identifier for the type of the next header.
stringipv6_nextstr A string representation of the type of the next header.
uint8_tipv6_hlim The hop limit.
ip6_addr_t*ipv6_src IPv6 source address.
ip6_addr_t*ipv6_dst IPv6 destination address.
stringipv6_saddr A string representation of the source address.
stringipv6_daddr A string representation of the destination address.
structip6_hdr*ipv6_hdr
A pointer to the raw IPv6 header.
Compatibility
This provider is compatible with the ip providers found in Solaris and Darwin.
Description
The DTrace ip provider allows users to trace events in the ip(4) and ip6(4) protocol implementations.
The ip:::send() probe fires whenever the kernel prepares to transmit an IP packet, and the ip:::receive()
probe fires whenever the kernel receives an IP packet. The arguments to these probes can be used to
obtain detailed information about the IP headers of the corresponding packet, as well as the network
interface on which the packet was sent or received. Unlike the dtrace_tcp(4) and dtrace_udp(4)
providers, ip provider probes are triggered by forwarded packets. That is, the probes will fire on
packets that are not destined to the local host.
Examples
The following script counts received packets by remote host address.
ip:::receive
{
@num[args[2]->ip_saddr] = count();
}
This script will print some details of each IP packet as it is sent or received by the kernel:
#pragma D option quiet
#pragma D option switchrate=10Hz
dtrace:::BEGIN
{
printf(" %10s %30s %-30s %8s %6s\n", "DELTA(us)", "SOURCE",
"DEST", "INT", "BYTES");
last = timestamp;
}
ip:::send
{
this->elapsed = (timestamp - last) / 1000;
printf(" %10d %30s -> %-30s %8s %6d\n", this->elapsed,
args[2]->ip_saddr, args[2]->ip_daddr, args[3]->if_name,
args[2]->ip_plength);
last = timestamp;
}
ip:::receive
{
this->elapsed = (timestamp - last) / 1000;
printf(" %10d %30s <- %-30s %8s %6d\n", this->elapsed,
args[2]->ip_daddr, args[2]->ip_saddr, args[3]->if_name,
args[2]->ip_plength);
last = timestamp;
}
Files
/usr/lib/dtrace/ip.d DTrace type and translator definitions for the ip provider.
History
The ip provider first appeared in FreeBSD 10.0.
Name
dtrace_ip — a DTrace provider for tracing events related to the IPv4 and IPv6 protocols
See Also
dtrace(1), dtrace_tcp(4), dtrace_udp(4), ip(4), ip6(4), ifnet(9), SDT(9)
Synopsis
ip:::receive(pktinfo_t*, csinfo_t*, ipinfo_t*, ifinfo_t*, ipv4info_t*, ipv6info_t*);
ip:::send(pktinfo_t*, csinfo_t*, ipinfo_t*, ifinfo_t*, ipv4info_t*, ipv6info_t*);
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