| .\" @(#) $Header: /tcpdump/master/libpcap/pcap_stats.3pcap,v 1.3 2008-04-06 02:53:22 guy Exp $ |
| .\" |
| .\" Copyright (c) 1994, 1996, 1997 |
| .\" The Regents of the University of California. All rights reserved. |
| .\" |
| .\" Redistribution and use in source and binary forms, with or without |
| .\" modification, are permitted provided that: (1) source code distributions |
| .\" retain the above copyright notice and this paragraph in its entirety, (2) |
| .\" distributions including binary code include the above copyright notice and |
| .\" this paragraph in its entirety in the documentation or other materials |
| .\" provided with the distribution, and (3) all advertising materials mentioning |
| .\" features or use of this software display the following acknowledgement: |
| .\" ``This product includes software developed by the University of California, |
| .\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of |
| .\" the University nor the names of its contributors may be used to endorse |
| .\" or promote products derived from this software without specific prior |
| .\" written permission. |
| .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED |
| .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF |
| .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| .\" |
| .TH PCAP_STATS 3PCAP "7 September 2009" |
| .SH NAME |
| pcap_stats \- get capture statistics |
| .SH SYNOPSIS |
| .nf |
| .ft B |
| #include <pcap/pcap.h> |
| .ft |
| .LP |
| .ft B |
| int pcap_stats(pcap_t *p, struct pcap_stat *ps); |
| .ft |
| .fi |
| .SH DESCRIPTION |
| .B pcap_stats() |
| fills in the |
| .B struct pcap_stat |
| pointed to by its second argument. The values represent |
| packet statistics from the start of the run to the time of the call. |
| .PP |
| .B pcap_stats() |
| is supported only on live captures, not on ``savefiles''; no statistics |
| are stored in ``savefiles'', so no statistics are available when reading |
| from a ``savefile''. |
| .PP |
| A |
| .B struct pcap_stat |
| has the following members: |
| .RS |
| .TP |
| .B ps_recv |
| number of packets received; |
| .TP |
| .B ps_drop |
| number of packets dropped because there was no room in the operating |
| system's buffer when they arrived, because packets weren't being read |
| fast enough; |
| .TP |
| .B ps_ifdrop |
| number of packets dropped by the network interface or its driver. |
| .RE |
| .PP |
| The statistics do not behave the same way on all platforms. |
| .B ps_recv |
| might count packets whether they passed any filter set with |
| .BR pcap_setfilter (3PCAP) |
| or not, or it might count only packets that pass the filter. |
| It also might, or might not, count packets dropped because there was no |
| room in the operating system's buffer when they arrived. |
| .B ps_drop |
| is not available on all platforms; it is zero on platforms where it's |
| not available. If packet filtering is done in libpcap, rather than in |
| the operating system, it would count packets that don't pass the filter. |
| Both |
| .B ps_recv |
| and |
| .B ps_drop |
| might, or might not, count packets not yet read from the operating |
| system and thus not yet seen by the application. |
| .B ps_ifdrop |
| might, or might not, be implemented; if it's zero, that might mean that |
| no packets were dropped by the interface, or it might mean that the |
| statistic is unavailable, so it should not be treated as an indication |
| that the interface did not drop any packets. |
| .SH RETURN VALUE |
| .B pcap_stats() |
| returns 0 on success and returns \-1 if there is an error or if |
| .I p |
| doesn't support packet statistics. |
| If \-1 is returned, |
| .B pcap_geterr() |
| or |
| .B pcap_perror() |
| may be called with |
| .I p |
| as an argument to fetch or display the error text. |
| .SH SEE ALSO |
| pcap(3PCAP), pcap_geterr(3PCAP) |