=head1 NAME

ping_iterator_get_info - Receive information about a host

=head1 SYNOPSIS

  #include <oping.h>

  int ping_iterator_get_info (pingobj_iter_t *iter,
		  int info,
		  void *buffer,
		  size_t *buffer_len);

=head1 DESCRIPTION

The B<ping_iterator_get_info> method can be used on an host iterator to return
various information about the current host.

The I<iter> argument is an iterator as returned by L<ping_iterator_get(3)> or
L<ping_iterator_next(3)>.

The I<info> argument specifies the type of information returned. Use the
following defines:

=over 4

=item B<PING_INFO_USERNAME>

Return the hostname of the host the iterator points to as supplied by the user.
This is the name you passed to L<ping_host_add(3)> and which you need to pass
to C<ping_host_remove>, too.

=item B<PING_INFO_HOSTNAME>

Return the hostname of the host the iterator points to. Since the name is
looked up using the socket address this may differ from the hostname passed to
L<ping_host_add(3)>. The hostname is actually looked up every time you call
this method, no cache is involved within I<liboping>.

It is recommended to include C<netdb.h> and allocate B<NI_MAXHOST> bytes of
buffer.

=item B<PING_INFO_ADDRESS>

Return the address used in ASCII (i.e. human readable) format. The address is
looked up every time you call this method. 40 bytes should be sufficient for
the buffer (16 octets in hex format, seven colons and one null byte), but more
won't hurt.

=item B<PING_INFO_FAMILY>

Returns the address family of the host. The buffer should be big enough to hold
an integer. The value is either B<AF_INET> or B<AF_INET6>.

=item B<PING_INFO_LATENCY>

Return the last measured latency or less than zero if the timeout occurred
before a echo response was received. The buffer should be big enough to hold a
double value.

=item B<PING_INFO_DROPPED>

Return the number of times that no response was received within the timeout.
This value is only increased but may wrap around at the 32E<nbsp>bit boundary.
The buffer should be big enough to hold a 32E<nbsp>bit integer, e.E<nbsp>g. an
C<uint32_t>.

=item B<PING_INFO_SEQUENCE>

Return the last sequence number sent. This number is increased regardless of
echo responses being received or not. The buffer should hold an integer.

=item B<PING_INFO_IDENT>

Return the ident that is put into every ICMP packet sent to this host. Per
convention this usually is the PID of the sending process, but since
I<liboping> can handle several hosts in parallel it uses a (pseudo-)random
number here. The buffer should be big enough to hold an integer value.

=item B<PING_INFO_RECV_TTL>

Returns the I<time to live> (TTL) of the received network packets. This number
depends on the value that was used by the remote host when it sent the echo
reply and has nothing to do with the B<PING_OPT_TTL> of L<ping_setopt(3)>. The
buffer should be big enough to hold an integer value.

=item B<PING_INFO_RECV_QOS>

Returns the value of the I<Quality of Service> (QoS) byte of the incoming IPv4
or IPv6 packet. This byte is not interpreted by I<liboping> at all and may be
DSCPE<nbsp>/ ECN or precedenceE<nbsp>/ ToS depending on your network setup.
Please see the appropriate RFCs for further information on values you can
expect to receive. The buffer is expected to an C<uint8_t>.

=back

The I<buffer> argument is a pointer to an appropriately sized area of memory
where the result of the call will be stored. The I<buffer_len> value is used as
input and output: When calling B<ping_iterator_get_info> it reports the size of
the memory region pointed to by I<buffer>. The method will write the number of
bytes actually written to the memory into I<buffer_len> before returning.

=head1 RETURN VALUE

B<ping_iterator_get_info> returns zero if it succeeds.

B<EINVAL> is returned if the value passed as I<info> is unknown. Both,
I<buffer> and I<buffer_len>, will be left untouched in this case.

If the requested information didn't fit into I<buffer> then the size that would
have been needed is written into I<buffer_len>; I<buffer> itself is left
untouched. The return value is B<ENOMEM> in this case.

=head1 SEE ALSO

L<ping_iterator_get(3)>,
L<liboping(3)>

=head1 AUTHOR

liboping is written by Florian "octo" Forster E<lt>ff at octo.itE<gt>.
Its homepage can be found at L<http://noping.cc/>.

Copyright (c) 2006-2017 by Florian "octo" Forster.
