config_defaults
set_api
set_max_sources
,
get_max_sources
set_options
,
get_options
set_iomode
get_iomode
set_errfilename
set_verbosity
,
get_verbosity
set_max_pkts
,
set_max_cells
,
set_max_blks
,
get_max_pkts
,
get_max_cells
,
get_max_blks
set_skip_pkts
,
get_skip_pkts
set_comment
,
get_comment
set_duration
,
get_duration
set_interval
,
get_interval
set_dropinterval
,
get_dropinterval
set_mintime
,
get_mintime
,
set_maxtime
,
get_maxtime
set_gzip
new_source
new_fsource
source_set_iomode
,
source_set_iomode_all
source_get_iomode
,
iface_get_iomode
coral_format_iomode
source_set_firmware
,
source_set_firmware_all
next_interface
,
next_source
next_src_iface
source_get_filename
source_get_name
get_source_count
interface_get_src
interface_get_type
source_get_type
interface_get_datalink
interface_get_physical
interface_get_bandwidth
source_get_number
,
interface_get_number
interface_get_capture_tv
interface_get_capturetime
cell_size
proto_abbr
,
proto_desc
,
proto_str
dns_op_to_str
,
dns_qtype_to_str
,
dns_qclass_to_str
dns_str_to_op
,
dns_str_to_qtype
,
dns_str_to_qclass
proto_id
proto_layer
write_open
write_rfopen
write_fopen
write_init_all
,
write_init_source
write_init_interface
write_cell
write_close
puts
fprint_data
,
print_data
fprint_cell
,
print_cell
fmprint_pkt
fprint_pkt
fmt_if_subif
fmt_subif
dump
,
dump_all
stats
,
stats_all
Libcoral operates on "sources", which include several types of live network interfaces/devices, and several types of tracefiles containing data recorded from one or more network interfaces/devices. The naming scheme for sources is described in the command usage document.
A typical program using Coral.pm has this basic structure:
configure Coral.pm and one or more sources open sources start sources while (read cell or packet != undef) { process the data we just read if (stop condition occurs) { stop sources } } close sources
All identifiers defined in this document are in the Coral
namespace, and are not exportable. Therefore, all methods must be fully
qualified, e.g.: Coral::quick_start().
In the descriptions below, there are several pairs of functions with the same base name, with or without an "_all" suffix. The function suffixed with "_all" operates on all sources, and the other one operates on a single source indicated by the src parameter.
quick_start(BOOL time_sort = 0,
BOOL partial_pkt = 1,
NUM api = API_PKT);
This Perl-only function does the configuration and startup for most common cases of CRL use. If finer control is needed, use the command line configuration and global configuration functions below. If time_sort equals 1, cells/packets will be sorted, otherwise they will not. If partial_pkt equals 0, then truncated packets are discarded by read_pkt(), otherwise they are accepted. Api allows the user to set the libcoral API being used; the default is API_PKT.
To limit the number of sources that will be allowed, call
set_max_sources()
before calling this function.
This function returns nothing. If any fatal errors are encountered, it exits.
The code consists of:
sub quick_start { my ($time_sort, $partial_pkt, $api) = @_; if (defined $time_sort and $time_sort != 0) { if (Coral::set_options(0, $Coral::OPT_SORT_TIME
) < 0) { Coral::puts("Warning: could not set time-sorting option!"); } } elsif (Coral::set_options($Coral::OPT_SORT_TIME
, 0) < 0) { Coral::puts("Warning: could not unset time-sorting option!"); } if (defined $partial_pkt and $partial_pkt == 0) { if (Coral::set_options($Coral::OPT_PARTIAL_PKT
, 0) < 0) { Coral::puts("Warning: could not unset partial packeting option!"); } } elsif (Coral::set_options(0, $Coral::OPT_PARTIAL_PKT
) < 0) { Coral::puts("Warning: could not set partial packeting option!"); } if (defined $api) { if (Coral::set_api($api) < 0) { Coral::puts("Warning: could not specify api!"); } } elsif (Coral::set_api($Coral::API_PKT) < 0) { Coral::puts("Warning: could not specify packet api!"); } if (Coral::config_arguments(scalar(@ARGV), \@ARGV) < 0) { Coral::puts("Error: could not parse command-line options!"); exit(1); } if (Coral::open_all() <= 0) { # no openable sources is considered an error Coral::puts("Error: could not open any sources!"); exit(1); } if (Coral::start_all() < 0) { Coral::puts("Error: could not start any sources!"); exit(1); } }
The following functions read coral commands from the command line or config files. The coral commands are described in the command usage document. These functions should only be called before open() or open_all().
You should call set_api()
before calling these functions to enable certain configuration commands.
Also, you should set the defaults for configurable values with the
set functions before calling any of these
functions, and (if needed) get the value after.
This way, the option and its default value will appear in the
usage()
message, and the user can override the
defaults with command line options. If your application does not use a
particular configurable value, you should leave it set to its initial value,
so it will not appear in the usage()
message,
and the config functions will not allow it
to be changed on the command line.
config_arguments(NUM argc,
LIST REF argv);
This function processes "-C
" options and sourcename arguments
contained in argv.
Argv is a reference to a list
of strings containing the command line;
argc is the number of strings in argv.
For a description of Coral options, see the
Command Usage documentation.
A CoralReef source is created (with new_source()
)
from each sourcename argument.
If an option syntax error is encountered, this function prints a usage message.
If other arguments are desired, use
config_options()
instead
and parse the arguments yourself;
if other options are desired, parse the options and arguments yourself and call
config_command()
for each "-C
" option.
Returns a non-negative integer for success, -1 for failure.
To limit the number of sources that will be allowed, call
set_max_sources()
before calling this function.
Sample call: $nxt_idx = config_options(scalar(@ARGV),
\@ARGV, "<outputfile>");
config_options(NUM argc,
LIST REF argv,
STR argmsg);
This function is like config_arguments()
, except it
processes only the options, not the non-option arguments.
If argmsg is undef
, this
function assumes that arguments (other than Coral options) are not allowed,
and considers it an error if other arguments are found;
otherwise, other arguments (but not other options) are allowed.
If successful, this function returns the index of the first non-option
argument.
It is the programmer's responsibility to handle
the remaining command line arguments.
If an error is encountered, this function returns -1, and prints a usage message
with usage($0, argmsg)
.
If other options are desired, use config_command()
instead.
Returns a non-negative integer for success, -1 for failure.
Sample call: $nxt_idx = config_options(scalar(@ARGV),
\@ARGV, "<outputfile>");
config_command(STR command,
STR filename,
NUM linenum);
Processes a config command. This function should be used instead of
config_options()
or config_arguments()
if you need to accept your own options in addition to CoralReef options,
or you want to accept CoralReef commands from inputs other than the command line.
Filename and linenum are printed in error
messages; pass undef and 0 to have them not printed.
Returns 0 for success, -1 for failure.
config_file(STR filename);
Process CoralReef commands in file filename.
This is not usually needed if config_arguments()
,
config_options()
, or config_command()
is used.
usage(STR appname,
STR argmsg = undef);
Prints a message describing the command line syntax of a CoralReef application named appname. If argmsg is not undef, it is appended to the syntax line. This is followed by descriptions of the CoralReef (-C) command line options.
Some example values for argmsg:
undef
"[<argument>]"
"[-f] [-b<N>] <source>..."
Coral::quick_start(0); # or 1 for time-sortingfollowed by the read_cell routines. If other options are desired, you must parse the options and arguments yourself. If a bad option is given, this code will print a message like this to stderr, followed by descriptions of the Coral commands:
Usage: app [-C <command>]... <source>
The following functions provide a way for the programmer to set global
configuration values, including default values for the configuration of
sources that have not yet been defined.
The set
functions can be called
before the config
functions to set default
values that can be overridden on the command line or config file, and will
be displayed in the usage
message.
If the integer configuration values are set to a negative value,
they will not be displayed in the usage
message.
The set
functions can also be called
after the config
functions
so their values can't be overridden.
They must not be called after sources are opened.
The set
functions return 0 if successful, or -1 for failure;
the get
functions return the value of the requested datum.
config_defaults();
Resets libcoral configuration to its default state. Should not be called while sources are open. The affected configuration values are: max_sources, options, duration, interval, dropinterval, mintime, maxtime, errfile, iomode, comment, gzip level, pcap filter, api, max_blks, max_cells, max_pkts, skip_pkts, bandwidth, physical protocol, datalink protocol, firmware.
set_api(NUM api);
The api parameter to set_api()
must be
API_CELL
, or
API_PKT
,
optionally bitwise ORed with
API_WRITE
.
It initializes libcoral for use with the corresponding APIs,
and should be called before any coral config, reading, or writing function.
Setting the APIs enables command line and configuration file options and functions that are specific to those APIs. Coral.pm will generate an error if any disallowed option or function is attempted.
The api parameter should contain exactly one of the following constants:
API | allowed configuration commands | allowed functions |
API_CELL
|
cells
blocks
deny
| |
API_PKT
|
packets
filter
deny
|
add_pcap_filter()
|
Commands and functions not listed under any API are valid for all APIs.
The api parameter may optionally be bitwise-ORed with this constant, if write or a rotating output file will be used:
API | allowed configuration commands | allowed functions |
API_WRITE
|
gzip
|
set_gzip()
|
Example: set_api(API_PKT | API_WRITE);
set_max_sources(NUM n);
get_max_sources();
set_max_sources()
sets the maximum number of allowed Coral
sources to n. It should be called before
config_arguments()
,
config_options()
,
config_command()
, and
new_source()
to restrict them.
It returns 0 if successful,
or -1 if n is negative or greater than 16.
get_max_sources()
returns the maximum number of allowed Coral
sources.
The default max_sources value is 16.
set_options(NUM off,
NUM on);
get_options();
set_options()
disables the options in the bitmask
off and enables the options in the bitmask on.
get_options()
returns a bitmask of currently enabled options.
The options are:
OPT_SORT_TIME
(default: off, unless quick_start(1) is used.)
read_cell_all()
and read_pkt()
read in timestamp order.
For this option to make sense, one of the following must be true:
all interfaces have start epochs and were started at the same time, or
all interfaces have unix epochs, or
the OPT_NORMALIZE_TIME
option is on.
If none of these conditions is true, libcoral will automatically enable the
OPT_NORMALIZE_TIME
option.
If your application requires time sorting, set this option before
the command-line config
functions so
"sort"
will not appear in the usage message.
OPT_ALIGNINT
(default: off)
OPT_PARTIAL_PKT
(default: on)
read_pkt()
to handle partial packets.
OPT_FATM_RAW_TIME
(default: off)
OPT_POINT_RAW_TIME
(default: off)
OPT_RAW_TIME
(OPT_FATM_RAW_TIME
| OPT_POINT_RAW_TIME
)
.
OPT_NORMALIZE_TIME
(default: on)
OPT_SORT_TIME
)
with different default epochs.
But normalizing may introduce inaccuracy if
the interfaces' hosts' CPU clocks are inaccurate,
and may introduce additional processing overhead.
The default epochs for the various types of interfaces are:
start_all
());
start_all
());
OPT_NO_FILTER
(default: off)
OPT_IP_CKSUM
(default: off)
fmt_get_payload()
to print and verify IP checksums.
OPT_IP_EXTHDR
(default: off)
get_payload()
to not skip IP extension headers.
OPT_IGNORE_TIME_ERR
(default: off)
OPT_NO_AUTOROTATE_ERRFILE
(default: off)
set_iomode(NUM off,
NUM on,
NUM first = -1,
BOOL fixed = 0);
This function sets the default I/O mode of all subsequently defined sources.
(To set the I/O mode of sources that have already been defined, use
source_set_iomode()
.)
The arguments to this function are:
config
functions, in applications
with a non-configurable iomode).
The I/O mode flags are:
flag | equivalent CLI iomode | description |
TX | tx | allow transmitting (not implemented) |
RX | rx | allow receiving |
RX_IDLE | idle | read all cells, including ATM idle cells |
RX_OAM | ctrl | read ATM OAM/RM cells |
RX_LAST | last | read last cell of each ATM AAL5 user PDU (packet) |
RX_USER_ALL | user | read all bytes of each packet or frame |
RX_ECHO | echo | retransmit received cells on devices which support it (always enabled on POINT cards) |
RX_UNKNOWN | for traces, read whatever cells are in the trace file; for devices, use default mode (i.e., rx first=48). Setting this flag clears all other settings. |
This function returns 0 for success, -1 for failure. It only affects sources that are created after it is called.
Setting first overrides a previously set
RX_USER_ALL
flag, and
setting the RX_USER_ALL
flag
overrides a previously set first value.
Attempting to set both at once has undefined results.
The default I/O mode is RX, and first==48. Currently, an attempt to explicitly use an I/O mode to read a trace that does not match the I/O mode used to record the trace will generate a warning, but all the data in the trace will still be read. In a future release, the read functions may filter trace files according to the I/O mode (or generate an error if that is not possible).
For a summary of the iomode options supported by the various interface types, see the command usage document.
get_iomode();
Return the default iomode
as set by set_iomode()
or command line options.
The iomode is returned in the form (flags, first_n).
set_errfilename(STR filename);
set_errfilename()
sets
the destination for future libcoral error and warning messages.
filename is the name of a file that will be opened by Coral.pm.
Any previously set error file will be closed only if it was set by name other
than "-".
If filename is undef
,
stderr will be used.
If filename is "-"
, stdout will be used.
The default message destination is stderr.
If the name of the error file contains "%", the error file will be
rotatable and the actual filename will be
generated as described in rf_open.
Unlike normal rotfiles,
a rotating error file is always writable
by Coral.pm;
it does not need to be started.
A rotatable error file will rotate automatically at the beginning of each
interval of read_pkt or read_pkts, unless then
OPT_NO_AUTOROTATE_ERRFILE
option is set.
In any case, rotate_errfile
can be called to rotate
the error file explicitly.
If rotation fails, the error file resets to stderr.
set_verbosity(NUM verbosity);
get_verbosity();
Set or get the verbosity level of Coral.pm. If verbosity==0, only errors are printed; if verbosity==1 errors and warnings are printed. The default verbosity is 1. To completely disable coral messages, set the verbosity to -1.
set_max_pkts(NUM n);
set_max_cells(NUM n);
set_max_blks(NUM n);
get_max_pkts();
get_max_cells();
get_max_blks();
These functions get or set the maximum record count that will be read by the reading APIs. When the limit is reached, reading functions will indicate EOF. If set to zero, there is no limit. All three counts are zero by default.
count | affected APIs |
max_pkts | packet |
max_cells | cell |
max_blks | cell |
set_skip_pkts(NUM n);
get_skip_pkts();
Get or set the number of packets that will be discarded by the packet reading API.
set_comment(STR comment);
get_comment();
Set or get the default comment that will be written in the file header by the
write
functions. The default comment may
be overridden by
the comment parameter of write_open()
.
set_duration(NUM duration);
get_duration();
Set or get the duration value.
If the duration value is greater than 0, it determines how long libcoral will read from sources after they are started; after the duration has expired, the reading function will indicate EOF. Libcoral uses both real time and cell timestamps to test duration, so it will work with tracefiles and devices receiving live traffic.
With the default duration of -1, the config
functions
will not allow duration to be set.
To have your application not use duration by default, but still let the
user override it, set it to 0
before calling the config
functions.
Before version 3.3.0, libcoral did not test duration when reading; the programmer was expected to handle it himself. Now, the programmer should do nothing other than enable it, and let libcoral's reading functions handle the duration.
Libcoral does not use SIGALRM to implement duration.
set_interval(LIST REF interval);
get_interval();
Set or get the interval value.
If the interval has not yet been set, get_interval()
returns (-1, -1, -1); otherwise, it returns (0, sec, usec),
where sec and usec are the seconds and microseconds,
respectively of a nonnegative interval value.
The interval value is never automatically used by libcoral; it just provides a
convenient and consistent way to let the user set an interval on the command
line or in a config file. The programmer may use the interval by passing
the result of get_interval()
in as a parameter to
read_pkt_init()
or
read_cell_i()
.
Libcoral uses cell/packet timestamps, not real time, to test for intervals.
Therefore the intervals it
reports will be correct for both tracefiles and devices, although the act
of reporting may be delayed because of internal buffering.
With the default interval of -1, the config
functions
will not allow interval to be set.
To have your application not use interval by default, but still let the
user override it, set it to 0.0
before calling the config
functions.
Libcoral does not use SIGALRM to implement interval.
See also: OPT_ALIGNINT
.
set_dropinterval(LIST REF dropinterval);
get_dropinterval();
Set or get the dropinterval value.
The default dropinterval value is { 0, 0 }.
If the dropinterval has been set to a negative value,
get_dropinterval()
returns (-1, -1, -1); otherwise, it returns (0, sec, usec),
where sec and usec are the seconds and microseconds,
respectively of a nonnegative interval value.
A positive value for dropinterval is used as the period with which
read_pkt()
will report packet drops on live pcap interfaces
to the error file.
Note that dropinterval uses setitimer() and SIGALRM. If that would interfere
with your application, you may prevent the user from setting dropinterval
on the command line by setting it to a negative value
before calling the config
functions.
The dropinterval is independent of the normal
interval and OPT_ALIGNINT
.
set_mintime(LIST REF t);
get_mintime();
set_maxtime(LIST REF t);
get_maxtime();
Set or get the mintime or maxtime value. If the desired value has not yet been set, the get functions return (-1, -1, -1); otherwise, they return (0, sec, usec), where sec and usec are the seconds and microseconds, respectively of a nonnegative time value.
Libcoral will discard all packets whose timestamp is less than mintime or greater than maxtime. Libcoral uses cell/packet timestamps, not real time, to test these time bounds, so the packets it discards will be correct for both tracefiles and devices.
With the default duration of -1, the config
functions
will not allow interval to be set.
To have your application not use time bounds by default, but still let the
user override them, set duration to 0
before calling the config
functions.
set_gzip(STR mode);
If mode is undef
, write_open()
will not gzip files
unless they end in ".gz".
If mode is "", write_open()
will gzip files with the
default parameters (compression level 1).
If mode is a non-empty string,
write_open()
will append it to the "wb" mode when calling
gzopen()
; see the zlib documentation for details.
new_source(STR sourcename);
Create a new coral source
from sourcename.
Sources are described in the
Command usage document.
Returns source pointer if successful, or undef
for failure.
This function is useful for creating a source directly from the program
(instead of through command line and config file with the
config
functions).
new_fsource(FILEHANDLE file,
STR sourcename = undef);
Like new_source, except that it uses the already-open
file handle file
instead of a filename.
If sourcename is not undef
, open()
will examine it for a prefix or suffix
to determine how to interpret the data read from file;
otherwise, open()
will assume data from file contains a
CoralReef (crl) trace.
This function is useful for creating a source directly from a
file handle in the program;
for example, a socket connected to another process that used
write_fopen()
.
Mixing CoralReef operations with other operations on handle file may have unpredictable effects.
source_set_iomode(SCALAR src,
NUM off,
NUM on,
NUM first = -1);
source_set_iomode_all(NUM off,
NUM on,
NUM first = -1);
These functions modify the I/O mode of the indicated already defined sources. The off, on, and first arguments are identical to those of set_iomode(). These functions return 0 for success, -1 for failure.
To set the default I/O mode of sources that have not yet been defined, use set_iomode().
source_get_iomode(SCALAR src);
iface_get_iomode(SCALAR iface);
Return the iomode of src or iface, respectively. Note that for live interfaces, it is the iomode of the interface that determines how data is read; the iomode of the source is just a default that an interface may inherit. For file interfaces, the iomode of the interface is that of the original device, and the iomode of the source has little meaning. The iomode is returned in the form (flags, first_n).
coral_format_iomode(LIST REF iomode);
Returns a human-readable representation of iomode.
iomode is a reference to a two-element array, such as [$flags, $first_n]
, where $flags and $first_n are returned by source_get_iomode or iface_get_iomode.
source_set_firmware(SCALAR src,
STR firmware);
source_set_firmware_all(STR firmware);
Set the location of the firmware file of source src, or of all sources. The firmware will be loaded when the source is opened. Returns 0 for success, -1 for failure.
/proc/dag
will report the device is "Busy");
the card must be re-initialized before CoralReef can read from it again.
open(SCALAR src);
open_all();
Open the indicated coral sources that have been created by
config_arguments()
, config_options()
,
config_command()
, and new_source()
,
but do not start them.
If successful, these functions return the number of interfaces opened.
If unsuccessful, these functions return -1 and close
the source which failed.
Note that a single tracefile source may contain multiple interfaces.
start(SCALAR src);
start_all();
Start capture on interface(s) of the indicated coral sources which have been
opened with open()
or open_all()
.
Additionally, start_all()
resets the clocks of all
open interfaces that allow it, to synchronize them.
A source can not be read until it is started with one of these functions.
(Prior to version 3.3, it was not strictly necessary to start tracefile
sources.)
stop_all();
stop(SCALAR src);
Stop capturing on all interfaces of the indicated device sources. Returns 0 for success, -1 for failure. After a source is stopped, it may still contain buffered data, which can be read until the reading function returns an EOF indication. These functions are not safe to call asynchronously (e.g., from a signal handler).
close_all();
close(SCALAR src);
Close all interfaces of the indicated sources, after flushing any partially filled blocks. Returns 0 for success, -1 for failure.
The packet reading functions may be used with any CoralReef interface that has been started. All time is measured against packet timestamps, so it works even for trace files that aren't in real time. If pcap filtering is enabled, packets that do not match the filter are discarded. If anonymization is enabled, IP addresses in packets will be anonymized, and non-IP packets are truncated.
Note that the data in packets returned by the packet API is not guaranteed to have any particular alignment.
read_pkt_init(SCALAR src,
SCALAR iface,
LIST REF interval = undef);
Prepare to read packets from an open src or iface with
read_pkt()
.
If iface is not undef
,
packets will be read from iface;
otherwise, if src is not undef
,
packets will be read from all interfaces of src;
otherwise, packets will be read from all interfaces of all open sources.
There is no restriction on reading multiple pcap sources or mixing pcap and
OCx sources, as there was prior to version 3.4.
If iface belongs to a source with multiple interfaces, data
from the other interfaces of that source will be discarded.
Packets can be read from only one set of sources at a time;
calling read_pkt_init()
invalidates any sources that were
previously initialized for packet reading.
Interval is the amount of time read_pkt()
will wait between returning statistical information (measured against packet
timestamps).
To set the interval, give read_pkt_init()
a
reference to a 2-element array representing the seconds
and microseconds of the interval, such as [100, 0], which might
come from get_interval()
.
Interval defaults to undef
, which disables interval handling.
read_pkt_init()
returns 0 if successful, or -1 if an
error occurs.
Because read_pkt()
must be able to compare timestamps,
read_pkt_init()
will automatically enable the
OPT_NORMALIZE_TIME
option if necessary.
read_pkt_init()
returns 0 if successful, or -1 if an
error occurs.
read_pkt(Pkt_result pkt_result,
Interval_result interval_result = undef);
Read a packet from one of the interfaces which have been
initialized with read_pkt_init()
.
If a packet filter has been set, only
packets that match the filter will be read.
Packets read are sorted by time only if the OPT_SORT_TIME
option
was set when read_pkt_init()
is called
(prior to version 3.6, packets were always sorted by time,
regardless of the setting of the OPT_SORT_TIME
option).
Even if sorting is disabled, packets will be returned in the correct interval,
and no packets will be returned after the duration has expired.
If the OPT_PARTIAL_PKT
option is turned off, only complete packets will be read
(but truncated packets are always counted by the truncated field of
Pkt_stats).
pkt_result and interval_result are
references to objects created by the user
that will be filled in by the call.
For success, read_pkt()
returns
the interface which was read,
and the contents of the objects indicate what happened:
if (defined pkt_result->packet) {
pkt_result
.pkt_result->packet
will reference a
Pkt_buffer
containing the link layer (LLC/SNAP, ethernet, etc) PDU.
On ATM interfaces,
pkt_result->header
will reference a
Pkt_buffer
containing the first 4 bytes of the ATM header of the last captured cell
of the packet (in network byte order);
pkt_result->trailer
will reference a
Pkt_buffer
containing the AAL5 trailer (in network byte order), if available; and
pkt_result->subiface
will contain the ATM vpvc
(in host byte order) from which the packet was read.
On IEEE 802.3/Ethernet interfaces carrying IEEE 802.1Q VLAN traffic,
pkt_result->subiface
will be the VLAN ID.
On other types of interfaces, pkt_result->header
and pkt_result->trailer
will be undef
,
and pkt_result->subiface
will be 0.
} elsif (not defined interval_result->stats) {
interval_result->begin
.
(interval_result->end
is not valid.)
} else {
interval_result->begin
and
ending at interval_result->end
has ended.
Statistics for the interval are contained in
interval_result->stats
.
All packets read after this point will have timestamps greater than
interval_result->end
, even if
the OPT_SORT_TIME
option is not enabled.
}
If the interval specified in read_pkt_init()
was
undef
or 0,
interval_result may be omitted or undef
,
and read_pkt()
will never return with
pkt_result->packet == undef
.
The beginning of an interval is not aligned to a multiple of
the interval size.
When reading from a live interface, internal buffering may cause reporting of
the end of the interval to be delayed, but the data reported will cover exactly
the requested interval.
(In versions 3.2.x, the reported interval included "quiet" (trafficless) time
after the end of the requested time.
In versions 3.1 and earlier, the data reported
included packets past the end of the interval that fell in the same internal
buffer as the end of the interval.) Interval comparisons are made against
packet timestamps, not a real clock, so the same results will be produced by
reading a live interface or reading a trace taken on that interface in the
same period.
The protocol of pkt_result->packet
is determined by the interface type.
For ATM interfaces, the protocol is determined by the virtual channel and
proto
configuration rules .
Note that if the configuration is incorrect, the packet buffer will
not make sense.
For TSH interfaces, the protocol for a valid packet is always
NETPROTO_IPv4
,
and IP options are always zero; the protocol of an invalid packet is
PROTO_UNKNOWN
.
Packets read from raw IP sources (i.e., pcap DLT_RAW) will have their
protocol set to NETPROTO_IPv4
or NETPROTO_IPv6
if they contain at least 1 byte of data; otherwise, they will have
protocol NETPROTO_RAW_IP
.
To indicate EOF, a stopped device, or
expired duration,
read_pkt()
returns
undef
with $! == 0
.
For an error, read_pkt()
returns undef
with
$!
set to indicate the type of error.
(Certain types of errors that were reported as EOF in versions prior 3.5
are now correctly reported as errors.)
If get_verbosity() >= 1, then
at the end of every interval,
if there were any packet errors
(nonzero fields in interval_result->stats
)
during the interval,
read_pkt()
prints warnings to the error file.
If intervals were not used, the warnings are printed only at EOF,
covering the entire duration.
Typical packet reading code looks like this:
{ $pkt_result = new Coral::Pkt_result; $interval_result = new Coral::Interval_result; Coral::read_pkt_init(undef, undef, $interval); while (1) { $iface = Coral::read_pkt($pkt_result, $interval_result); if (!iface) { # error last; } if (defined $pkt_result->packet) { # got packet ... } elsif (not defined $interval_result->stats) { # beginning of interval ... } else { # end of interval ... } } }
get_payload(Pkt_buffer src,
Pkt_buffer dst);
src is a reference to a
Pkt_buffer
containing a datagram or packet
(e.g., packet_result->packet from read_pkt())
with src->caplen > 0
.
Dst is also a reference to a Pkt_buffer,
but is created by the user, e.g.:
"$argument = new Pkt_buffer;
".
get_payload()
skips past the lower level (outer) protocol
encapsulation in src and fills in dst with information
about the payload of src
(see Pkt_buffer).
If get_payload()
understands the src protocol
but does not recognize the protocol of the payload,
dst->protocol
will contain
PROTO_UNKNOWN
or some other undefined value.
get_payload()
returns 0 if it successfully parsed
the src protocol information, or one of the following negative
error codes:
A return value of ELENGTH indicates that some desired part of the
packet was truncated, but dst will still contain as much information
as was available.
For example, if src contained an IPv4 packet truncated between
the length field and the protocol field, then
dst->buf
will point to the beginning of the next layer,
and dst->totlen
will be the correct length of the next layer,
but dst->protocol
will be PROTO_UNKNOWN
.
For all other error return values, the contents of dst are undefined.
The recognized protocols are listed in the
Protocols section of the
Command Usage document.
Protocol identifiers are formed by concatenating
the prefix and the name, in the Coral namespace;
e.g., DLT_ETHER
.
By default, the IPv6 extension headers
HOPOPTS, ROUTING, FRAGMENT, and DSTOPTS are skipped;
but if the OPT_IP_EXTHDR
option is on,
they are treated as encapsulated protocols.
The extension headers AH and ESP are never skipped.
So, for example, say you have an Ethernet frame containing an IPv6 packet
with a Routing header, Fragment header, and UDP datagram.
If you call get_payload()
with that packet as src,
and then repeatedly with the dst of the previous call as the src
of the next,
with OPT_IP_EXTHDR
off,
the value of dst->protocol
after each successive call would be
NETPROTO_IPv6
,
IPPROTO_UDP
, and
PROTO_UNKNOWN
,
respectively.
But the same sequence with OPT_IP_EXTHDR
on
would result in
NETPROTO_IPv6
,
IPPROTO_ROUTING
,
IPPROTO_FRAGMENT
,
IPPROTO_UDP
, and
PROTO_UNKNOWN
.
(In versions 3.5.0 and 3.5.1, this function behaved as if OPT_IP_EXTHDR
were always on.)
Note: TSH files contain IPv4 packet headers only, and when CoralReef reads an IPv4 packet from a TSH file it fills the missing IP options (if any) with zeros to create a syntactically valid substring of an IP packet.
fmt_get_payload(Pkt_buffer src,
Pkt_buffer dst,
STR REF buf);
fmt_get_payload()
is like
get_payload()
, except that it also writes
human-readable information about the lower level protocol into buf.
Returns a nonnegative number if successful,
or -1 for any of the following errors:
vsnprintf()
is not available on your system
and buf is not undef
;
or any of the errors listed in the documentation for
get_payload().
A return value of ELENGTH indicates that some desired part of the
packet was truncated, but dst and buf will still contain as much
information as was available.
For all other error return values, the contents of dst and buf
are undefined.
The information written into buf attempts to cover all relevant information
about the protocol. Irrelevant information is omitted for brevity (for
example: for TCP, the urgent pointer and acknowledgment number are printed
only if the corresponding flags are set;
for IPv4, type-of-service is printed only if it is nonzero,
and the fragment offset is printed only if the packet is a fragment).
The IP checksum will be printed and verified only if the
OPT_IP_CKSUM
option is set.
get_payload_by_proto(Pkt_buffer src,
Pkt_buffer dst,
NUM proto);
get_payload_by_layer(Pkt_buffer src,
Pkt_buffer dst,
NUM layer);
These functions search for the outermost packet in src whose protocol is proto or protocol layer is layer, and copy that packet's information to dst. The copied packet will be src itself if its protocol matches the criterion; otherwise these functions repeatedly call get_payload() to find encapsulated packets. These functions return 0 if successful, or -1 if the proto or layer is not found, or for any of the errors listed in the documentation for get_payload().
pkt_truncate(Pkt_buffer pkt,
NUM layer,
NUM unknown,
NUM payload);
Effectively truncates packet by protocol: keeps the headers of the first layer layers plus payload bytes of layer layer payload. It does this by reseting pkt->caplen to the lowest of:
PROTO_UNKNOWN
Returns the same values as get_payload().
If libcoral was compiled with libpcap, these functions can be used to set pcap filter expressions. Pcap filters can be used with any type of interface, not just BPF devices. The filter will be executed when it is most efficient: in the kernel if the interface is a BPF device, or before AAL5 reassembly (if possible) if the interface is an ATM Coral device or file. The packet reading functions will return only packets which match the filter.
add_pcap_filter(STR expr);
add_pcap_prefilter(STR expr);
add_pcap_ipfilter(STR expr);
If expr is not undef
, add_pcap_filter()
sets expr as a global pcap filter expression.
If a filter expression was already set (either by this function or by
config "filter" commands),
the old and new expressions are joined as
"(old_expr) and (expr)
".
The expression will be compiled and set on every source that is subsequently
opened; it has no effect on sources that are already open.
If expr is undef
,
add_pcap_filter()
clears
any previously set global pcap filter expression.
These functions will not work until set_api(API_PKT)
is called.
This function returns 0 if successful,
or -1 with $! set if there is an error.
add_pcap_prefilter()
is similar to
add_pcap_filter()
,
except it sets a "prefilter", which is used only on ATM interfaces,
on the first ATM cell, before AAL5 reassembly. A prefilter
can be used to avoid unnecessary reassembly, but only if the first ATM
cell contains enough information to apply the filter. It is up to the
user to make sure the prefilter does not need information that does
not fit in the first cell.
add_pcap_ipfilter()
is similar to
add_pcap_filter()
,
except that for each packet CoralReef first skips past layer 2 to find an
IP packet. If no IP packet is found, the packet is discarded; otherwise, the
filter is tested starting at the IP header.
This is useful when packets contain IP encapsulated in some layer 2
protocol that pcap filters can not parse, but CoralReef can,
such as MPLS.
See also the section on -Cfilter in the command usage document.
get_pcap_filter();
get_pcap_prefilter();
get_pcap_ipfilter();
Returns the text of the global pcap filter expression
previously set by
add_pcap_filter() or add_pcap_prefilter()
and/or by config
"filter" or "prefilter"
commands.
Returns undef
if no filter expression has been set.
The cell reading functions may be used only with ATM interfaces that have been started. For working with layers 3 and above, the packet reading functions are usually better.
After any of these reading functions are successful,
binfop will be a reference to a byte string representing the block info,
and cellp will be a reference to a Cell object.
binfop can be parsed by the Unpack functions.
binfop may be passed a value of undef
if the block info will not be
needed.
If timeout is undef
or omitted,
these functions will wait until data are available or an interrupt occurs.
But if timeout is not undef
,
these functions will also return after
the amount of time specified in timeout even if there are no data.
To set the timeout, input a reference to a
2-element array representing the seconds and microseconds
of the timeout, such as [100, 0].
The deny
protocol rules
are applied by the cell reading functions
to filter the cells and determine their protocol.
Note: prior to version 3.4.2, the cell reading functions did not apply
the the configuration deny
rules.
Calls to the different CoralReef reading functions may not be interleaved on a given set of sources.
A call to any CoralReef reading function on a given set of sources invalidates all data in buffers set by previous calls to any reading functions on the same set of sources.
undef
with $!==0
for EOF,
stopped device, or
expired duration.
(If end-of-file is encountered someplace other than a block boundary, it
is considered an error.)undef
with $!==EAGAIN
if timeout is exceededundef
with $!==EBADF
if sources are not ATM.undef
with other $! value for other errorsundef
interface reference for success
read_cell(SCALAR src,
STR REF binfop,
Cell cellp,
LIST REF timeout = undef);
read_cell_all(STR REF binfop,
Cell cellp,
LIST REF timeout = undef);
read_cell()
reads a single cell from the indicated source;
read_cell_all()
reads from all open sources.
If the OPT_SORT_TIME
option is off,
read_cell_all()
reads cells in the most
efficient order (i.e., block order);
but if the OPT_SORT_TIME
option is on, it will read them
in time-sorted order (interleaving cells from blocks of different interfaces).
If the OPT_SORT_TIME
is set,
timeout is ignored (it is always treated as undef
).
See the section introduction above for more details and return values.
read_cell_i(SCALAR src,
STR REF binfop,
Cell cellp,
Interval_result int_result,
LIST REF interval = undef);
read_cell_all_i(STR REF binfop,
Cell cellp,
Interval_result int_result,
LIST REF interval = undef);
These functions are like
read_cell()
and read_cell_all()
,
except that there is no timeout and they support intervals.
If the value of interval is greater than 0.0, then
time sorting is automatically enabled regardless of the setting of the
OPT_SORT_TIME
option, and
whenever *interval
seconds have passed or EOF is reached,
the functions will return non-undef
with
cellp == undef
to indicate that an interval has ended,
and the start
and end
fields of int_result
will be filled in with the boundaries of the interval.
binfop
is undefined at the end of an interval.
int_result->stats
is always undef
.
When EOF is reached, the final partial interval is returned, and the
next call will return undef
.
See the section introduction above for more details and return values.
cell_to_pkt(SCALAR iface,
Cell cell,
Pkt_buffer pkt);
cell is a reference to a Cell object,
returned by read_cell.
cell_to_pkt
fills in the object
referenced by pkt with
information from cell and iface,
for use with functions that expect a
Pkt_buffer argument.
Iface and the cell's vp:vc are used to determine the protocol of
the data according to the configuration
proto
rules.
If iface is undef
,
pkt->protocol
will be set to
PROTO_UNKNOWN
.
The return value is 0 if
iface and the cell's vp:vc match a configuration
deny
rule, otherwise 1.
get_ip(SCALAR iface,
REFERENCE data);
This Perl-only function is another shortcut for a common action:
taking a Cell or Pkt_buffer
and extracting the IPv4-level data from it.
iface is the interface from which the
Cell or Pkt_buffer was read
(by read_cell() or
read_pkt()).
data is a
reference to the
Cell or Pkt_buffer itself.
Returns the byte string
data starting with the IPv4 header, or undef
if there was any error.
(IP version != 4 counts as an error.)
The byte string can then be parsed by the
Unpack functions.
next_interface(SCALAR iface);
next_source(SCALAR src);
If iface/src is undef
,
these functions return a pointer to the first CoralReef interface/source;
otherwise, they return a pointer to the interface/source following
iface/src.
They return undef
if there is no next interface/source.
The order in which interfaces/sources are returned
is not necessarily the order in which they were opened.
These functions are used to step through all interfaces/sources, for example:
$iface = undef; while (($iface = next_interface($iface))) { # operate on iface }
next_src_iface(SCALAR src,
SCALAR iface);
,
Like next_interface(), except it only returns interfaces of src.
source_get_filename(SCALAR src);
Returns the name of the file or network interface of source src,
without a
coral type prefix.
Returns undef
if src is bad.
source_get_name(SCALAR src);
Returns the name of the source src,
including a
coral type prefix,
if any.
Returns undef
if src is bad.
get_source_count();
Returns the number of sources.
interface_get_src(SCALAR iface);
Returns the source descriptor of the source to which
interface iface belongs, or undef
if iface is bad.
interface_get_type(SCALAR iface);
Return the original (hardware) type of interface iface, or return TYPE_NONE if iface is invalid or its type is unknown.
source_get_type(SCALAR src);
Return the type of source src, or TYPE_NONE if src is invalid or its type is unknown. For live sources, the type will be one of the types listed in the description of interface_get_type(); for file sources, the type will be one of the following:
interface_get_datalink(SCALAR iface);
Return the data link layer type of interface iface,
or PROTO_UNKNOWN
if the protocol is unknown,
or -1 if iface is bad.
The data link layer type is one of the DLT_*
(layer 2) constants
defined in the
Command Usage document.
interface_get_physical(SCALAR iface);
Return the physical layer type of interface iface,
or PROTO_UNKNOWN
if the protocol is unknown,
or -1 if iface is bad.
The physical layer type is one of the PHY_*
(layer 1) constants
defined in the
Command Usage document.
interface_get_bandwidth(SCALAR iface);
Return the bandwidth (in kilobits per second) of interface iface, or 0 if the bandwidth is unknown, or -1 if iface is bad.
source_get_number(SCALAR src);
interface_get_number(SCALAR iface);
Return a non-negative integer identifier of source src or interface iface, or return -1 if src or iface is bad. The identifier returned is not really useful except as a label. To print an interface number, see fmt_if_subif().
interface_get_capture_tv(SCALAR iface);
Returns the time (relative to the unix epoch) of the start of the capture on interface iface in the form of (sec, usec), or (undef, undef) if there was an error. It will return (0,0) if the start time is unknown. Note: the microsecond component will always be 0 in traces in the old NLANR and MCI formats and traces made with CoralReef versions prior to 3.2.2 (format version 9).
interface_get_capturetime(SCALAR iface);
Returns the integer component of the value that would be returned by
interface_get_capture_tv(iface)
.
cell_size(SCALAR iface);
Returns the size of the cell structure used by iface.
get_cell_timestamp(Cell cell);
Defunct. The Cell object now has a member
called timestamp.
Old call: $stamp = get_cell_timestamp($cell);
New call: $stamp = $cell->timestamp($iface);
read_clock_sec_nsec(SCALAR iface,
SCALAR t);
read_clock_double(SCALAR iface,
SCALAR t);
These functions parse the timestamp t, which belongs to a Cell or Pkt_buffer read from interface iface, and convert it to a more useful format.
If the OPT_NORMALIZE_TIME
option is set, the result will be measured from the unix epoch;
otherwise, the result will have some interface-dependent epoch.
Normalization may introduce some error in the precision; this error will be
the same for all timestamps from the same interface, but may be different
for different interfaces.
These functions automatically correct the case in which the FORE card doesn't
increment the firmware clock because it misses a hardware clock wrap,
unless the OPT_FATM_RAW_TIME
option is set.
read_clock_double()
returns the time
as floating point number of seconds.
Note that some precision may be lost by the conversion to double.
read_clock_sec_nsec()
returns the time as a 2-element list of seconds and nanoseconds.
proto_abbr(NUM protocol);
proto_desc(NUM protocol);
proto_str(NUM protocol);
Protocol is a prefix_name
constant (listed in the
Command Usage document)
identifying a communication protocol.
These functions return a string describing protocol:
proto_abbr
: a short name, or undef
;proto_desc
: a long description, or undef
;proto_str
: a long description, or "unknown N".
dns_op_to_str(NUM qtype);
dns_qtype_to_str(NUM qtype);
dns_qclass_to_str(NUM qclass);
These functions return a string describing DNS opcode op, qtype qtype, or qclass qclass, respectively. Strings are taken from http://www.iana.org/assignments/dns-parameters as of the time the library was written; codes not present in that document are formatted as numbers. The return value may point to a static data area that will be overwritten with each call.
dns_str_to_op(STR str);
dns_str_to_qtype(STR str);
dns_str_to_qclass(STR str);
These functions return a code corresponding to str, which is a string describing a DNS opcode op, qtype qtype, or qclass qclass, respectively. Strings are taken from http://www.iana.org/assignments/dns-parameters as of the time the library was written; the return value for a string not present in that document is -1 (cast to the return type).
proto_id(STR name);
Returns a protocol id constant (listed in the
Command Usage document)
corresponding to name, which may be a short abbreviation or a
long description as returned by
proto_{abbr,desc,str}()
.
Returns PROTO_ILLEGAL
if name is not a valid protocol name or
abbreviation.
proto_layer(NUM protocol);
Returns the layer number of protocol.
The rotating file API allows a programmer to write to a series of
files, occasionally changing the filename. This can be useful for
long-running processes whose output you may want to read before
the process is complete, help with organizing output data, or simply
to keep output files at a manageable size.
It is usually fairly simple to convert existing code that writes to a
single file into code that writes to a rotating file by replacing
the open and close calls and possibly inserting rotation directives.
If you want the file to rotate every interval, you can use the
ROT_AUTO flag, and let libcoral handle everything for you;
if you want more control over when rotations occur, you can call the
rf_start()
and rf_end()
functions yourself.
The functions:
rf_open_filehandle(REF handle,
STR name,
STR tmp = undef,
NUM flags = 0);
Creates a Rotfile object to be used for writing a series of files.
An iteration of the Rotfile can be started
either manually with rf_start()
,
or automatically at the beginning of each interval
if flags has the ROT_AUTO bit set.
When an iteration is started, the object
referenced by the
handle parameter is filled in with a
filehandle.
Then, that value can be used as the destination of appropriate writing
functions.
Name should contain % conversion specifiers; these will be replaced each time the underlying file is rotated. The following conversions are recognized:
%i
- iteration counter (starting at 0)
%s
- seconds (from the tv parameter of
rf_start()
)
%f
- 6 digits of fractional seconds (from the tv
parameter of rf_start()
)
%F
- equivalent to %Y-%m-%d
in strftime()
All other % specifiers will be replaced as in strftime(),
using the tv parameter of rf_start()
.
Additionally, all specifiers other than %f
may contain any of the
modifiers allowed in %s
by printf (e.g., "%03i"
).
All specifiers other than %s
are formatted in the
local timezone according to the TZ
environment variable;
to use UTC instead, set TZ="UTC"
in the environment.
If tmp is undef, a file with the specified name
is opened immediately with each call to rf_start()
;
otherwise, a temporary file is used, which is renamed to the specified
name when rf_end()
is called.
If tmp is not "", it is used as the name of the temporary file;
if tmp is "", a temporary name is generated automatically,
with the same directory as name.
To allow the programmer to write code that unconditionally uses the rf functions for standard output as well as files, the created rotfile object will behave differently if name is "-":
rf_start()
other than the first have no effect
rf_end()
have no effect
If flags has the ROT_AUTO bit set,
the rotfile will rotate automatically at the beginning of every interval of
read_pkt
or read_pkts
.
But if name did not contain any "%" specifiers, only the first
(possibly implicit) interval
will cause an automatic rf_start
call; thus, without "%",
the file will not rotate every interval, but you still do not
need to call rf_start
manually before the first write.
Whatever the setting of ROT_AUTO, you can still call
rf_end
and rf_start
to
manually rotate the rotfile.
But if flags is undefined or does not contain
ROT_AUTO, or if you want to write to the rotfile
before the first interval, you must call rf_start
manually at least once before writing to the file.
If the filename generated from name by rf_start
would
be a duplicate of a previously used name, it will automatically append
an iteration counter to the filename to avoid overwriting previous files.
This safety mechanism will be disabled if flags
is defined and has the ROT_UNSAFE bit set.
This function returns a reference to a newly created Rotfile if successful; failure is indicated by returning undef with $! set and printing a message.
Typical rotating file code has this structure:
my $handle = new IO::Handle; my $rf = rf_open_filehandle($handle, $name); rf_start($rf); while (there is data) { if (it is time to rotate the file) { rf_end($rf); rf_start($rf); } print $handle data; } rf_close($rf);
If you wanted to rotate on interval boundaries, you could use the ROT_AUTO flag and omit the calls to rf_start and rf_end.
rf_start(Rotfile rf,
LIST REF tv);
Starts an iteration of rotating file rf which has been opened by
rf_open_filehandle()
.
The filename is fixed at this point
using the time value in tv for the strftime expansion.
tv is a reference to a 2-element array representing the
seconds and microseconds time value.
If tv is undef
, the current time is used.
If temporary files were requested when rf was opened, this filename
is not actually used yet, it is just recorded for later use.
Next, a real file is actually opened, unless the filename was "-"
and this is not the first call to rf_start
.
If a disk file is opened,
it will have mode 666 modified by the process umask.
Returns 0 for success;
failure is indicated by returning -1 with $! set and printing a
message.
rf_end(Rotfile rf);
Ends an iteration of rf by
closing the real file associated with this iteration of the rotfile,
unless the filename was "-".
If temporary files were requested when rf was opened, the
file that was created by rf_start()
is now renamed to the permanent file name.
The iteration counter of rf is incremented (this counter appears
in place of "%i" in the filename created by rf_start()
).
Writing to the file associated with rotfile
is not allowed until rf is started again with rf_start()
.
If the filename was "-", or
rf_start(rf)
has not been called since
rf was opened or ended,
this function has no effect.
Returns 0 for success;
failure is indicated by returning -1 with $! set and printing a
message.
rf_close(Rotfile rf);
Implicitly calls rf_end(rf)
if necessary,
and deallocates all resources associated with rf.
To guarantee that all data is actually written to a file,
it is important to call rf_close before exiting the program.
Returns 0 for success;
failure is indicated by returning -1 with $! set and printing a
message.
rotate_errfile(LIST REF tv);
Rotates the error file
(if the configured error file name contained "%"),
using tv as the timestamp for substitutions in the filename
as in rf_start()
.
Returns 0 for success;
failure is indicated by returning -1 with $! set and printing a
message.
If rotation fails, the error file resets to stderr.
The writing API allows a programmer to copy cells or blocks from a CoralReef source to a CoralReef-format trace file. The source is typically a OCx device (for doing data capture), but may also be another trace file (useful for encoding, or converting from another format).
For information on writing packets in pcap format, see the section on pcap conversion.
write_open(STR name,
STR comment = undef,
STR encoding = undef,
NUM version = 0);
Open file name for writing a trace file in CoralReef format.
If the name ends in ".gz"
or the
"gzip" configuration option was
given, and CoralReef was compiled with libz, the file will be gzipped.
(set_api() must be called with the API_WRITE bit
to enable the "gzip" configuration option.)
A leading ~
in name is expanded to a home directory.
If the name is "-"
, data will be written to stdout.
Returns a coral write descriptor (writer)
for success, undef
for failure.
The recommended suffix for CoralReef trace files is ".crl", and for encoded
CoralReef trace files is ".enc.crl".
Writes comment and encoding strings into the file header, with encoding version set to version. Comment and encoding default to undef, version defaults to 0. Comment may be up to 255 characters, encoding may be up to 31 characters.
To ensure that all data from all sources are read, you must call
stop()
on any sources which have not reached EOF.
Then, to ensure that all data from all sources are written, you must call
write_close()
on the writer, before calling
close()
on the sources.
write_rfopen(STR name,
STR tmp = undef,
STR comment = undef,
STR encoding = undef,
NUM version = 0);
Like write_open()
, except the file can be rotated.
The file name should contain % escapes; these will get expanded with
every rotation. The legal escapes are the same as those in
rf_open()
.
The underlying file is not actually opened until
rf_start()
or the first write;
the timestamp used in filename expansion is the current time.
Use write_end()
to end the current iteration
of a file; a new iteration will be started with the next
rf_start()
or write.
Use write_close()
when done writing to the file;
it will do an implicit write_end()
if one has
not been done since the last rf_start()
or write.
If tmp is not undef, the current iteration file will be given a
temporary name, which will be renamed to the permanent name
by write_end()
; this guarantees that files matching
name are always complete. If tmp is not "", it is used as
the temporary name; if it is "", a temporary name is generated automatically,
with the same directory as name.
write_fopen(FILEHANDLE file,
STR comment = undef,
STR encoding = undef,
NUM version = 0);
Like write_open, except it uses the already-open file handle file instead of a filename.
Mixing CoralReef operations with other operations on handle file may have unpredictable effects.
write_init_all(SCALAR writer);
write_init_source(SCALAR writer,
SCALAR src);
Prepare to write data from the indicated sources to writer. Returns 0 for success, -1 for failure.
write_init_interface(SCALAR writer,
SCALAR iface);
Prepare to write data from a single interface iface to tracefile writer. Returns 0 for success, -1 for failure.
write_cell(SCALAR writer,
SCALAR iface,
SCALAR cell);
Write cell to writer. iface indicates which interface the cell was read from (as returned by a CoralReef reading function). Returns 0 for success, -1 for failure.
write_close(SCALAR writer);
Close the coral trace indicated by writer.
Returns 0 for success, -1 for failure.
To ensure that all data from all sources are read, you must call
stop()
on any sources which have not reached EOF.
To ensure that all data from all sources are written, you must call
write_close()
on the writer, before calling
close()
on the sources.
puts(STR str);
Like the standard C function puts(str)
, except that it prints to the
CoralReef errfile instead of stdout,
and it is guaranteed to not modify errno
.
fprint_data(FILEHANDLE file,
NUM indent,
SCALAR data,
NUM len);
print_data(NUM indent,
SCALAR data,
NUM len);
print_data
prints len bytes from data
to stdout
in a easily readable format:
16 hex values per line, with each line indented indent spaces.
fprint_data
is like
print_data
, except
it prints to file instead of stdout
.
fprint_cell(FILEHANDLE file,
NUM indent,
SCALAR iface,
SCALAR cell);
print_cell(NUM indent,
SCALAR iface,
SCALAR cell);
print_cell
prints cell (which was read from iface) to stdout
in an easily readable format, with the timestamp in seconds, the
ATM header expanded by fields, and the payload in hex,
with each line indented indent spaces.
This format is used by the application crl_print
.
fprint_cell
is like print_cell
, except
it prints to file.
fmprint_pkt(FILEHANDLE file,
SCALAR iface,
SCALAR timestamp,
NUM minlayer,
NUM maxlayer,
Pkt_buffer packet,
Pkt_buffer header,
Pkt_buffer trailer);
fmprint_pkt
prints packet and optionally
header and trailer
(which were read from iface) to file
in an easily readable format, with the timestamp in seconds.
Protocol layers less than minlayer will be skipped;
layers between minlayer and maxlayer will be
expanded by fields in an easily readable format,
as by fmt_get_payload()
;
layers greater than maxlayer or not understood by libcoral
will be printed in hex.
This format is used by the application crl_print_pkt
.
fprint_pkt(FILEHANDLE file,
SCALAR iface,
SCALAR timestamp,
NUM maxlayer,
Pkt_buffer packet,
Pkt_buffer header,
Pkt_buffer trailer);
Equivalent to
fmprint_pkt(iface, timestamp,
1, maxlayer, packet,
header, trailer)
.
fmt_if_subif(SCALAR iface,
NUM subif);
fmt_if_subif
returns a formatted
representation of iface id and subif .
If the data link type of iface does not have subinterfaces,
the format is just the interface number
(interface_get_number);
if it does, the format is
"if[subif]", where subif is formatted as by
fmt_subif()
.
fmt_subif(SCALAR iface,
NUM subif);
fmt_subif
returns a formatted
representation of subif.
The format depends on the data link type of iface:
dump(SCALAR src);
dump_all();
Prints information about the indicated sources to the CoralReef errfile,
like the application crl_info
.
stats(SCALAR src);
stats_all();
Prints statistics about the indicated sources to the CoralReef errfile.
filename(STR str);
Returns a copy of str
with any leading "~name/
" replaced with the home directory of user
name, and any leading "~/" replaced with the home directory of the user
who owns the process.
in_cksum_add(NUM psum,
SCALAR data,
NUM len);
in_cksum_result(NUM psum);
Calculates the internet checksum of the string in data. Usage:
psum
to 0$psum =
in_cksum_add($psum, data, len)
for each segment of buffer,
where data is the segment
and len is the length of the segmentin_cksum_result($psum)
to get result.Segments must be short-aligned. Entire message must have length less than 32768.
This class is returned by a call to one of the read_cell functions, representing a cell and its members. All member functions require the interface as an argument, e.g.:
$header = $cell->header($iface);
This header (or the payload) can then be parsed with the Unpack functions. The Cell member functions are:
SCALAR timestamp # time cell was read (interpret with read_clock functions) STR header # link layer header (e.g., ATM) STR hec # HEC that libcoral doesn't include in the header STR payload # link or sub-network layer packet
NUM caplen # length of data actually captured in buf
NUM totlen # total length of pkt (negative if unknown)
STR buf # data (in a byte-string format)
NUM protocol # protocol (ie, what kind of buffer is this?)
The byte string in buf
can be parsed by the Unpack functions.
NUM l2_recv; # Layer 2 PDUs received NUM l2_drop; # Layer 2 PDUs dropped NUM pkts_recv; # packets received NUM pkts_drop; # packets dropped NUM truncated; # packets truncated by insufficient capture NUM driver_corrupt; # cell looks bad from the capture device NUM too_many_vpvc; # too many simultaneous vpvc pairs NUM buffer_overflow; # AAL5 cell stream > MAX_PACKET_SIZE NUM aal5_trailer; # AAL5 trailer had bad length NUM ok_packet;
The l2_recv
and l2_drop
fields count layer 2 PDUs
(e.g., ATM cells), and may not be totally accurate.
On interfaces that operate on blocks (i.e., POINT, FORE ATM, and DAG),
the layer 2 PDUs reported are those belonging to every block that started
within the interval. If there are many blocks per interval the error should
be small, but if traffic is low the error is more significant.
Most types of interfaces set only a subset of these statistics (the rest will always be zero):
l2_recv
,
l2_drop
,
pkts_recv
,
truncated
,
driver_corrupt
,
too_many_vpvc
,
buffer_overflow
,
aal5_trailer
pkts_recv
,
pkts_drop
,
truncated
pkts_recv
,
pkts_drop
(see also dropinterval)
pkts_recv
,
truncated
SCALAR timestamp # time packet was read (interpret with read_clock functions) Pkt_buffer packet # link or sub-network layer packet Pkt_buffer header # link layer header (eg, ATM) Pkt_buffer trailer # link layer trailer (eg, AAL5) NUM subiface # sub-interface id (ATM VPVC or VLAN ID)
The subiface
field can be formatted with
fmt_subif().
LIST begin # beginning of interval (sec, usec) LIST end # end of interval (sec, usec) Pkt_stats stats # statistics for interval
An opaque structure that should be accessed through the rf_* functions.