include/net/snmp.h

   1 /*
   2  *
   3  *              SNMP MIB entries for the IP subsystem.
   4  *
   5  *              Alan Cox <gw4pts@gw4pts.ampr.org>
   6  *
   7  *              We don't chose to implement SNMP in the kernel (this would
   8  *              be silly as SNMP is a pain in the backside in places). We do
   9  *              however need to collect the MIB statistics and export them
  10  *              out of /proc (eventually)
  11  *
  12  *              This program is free software; you can redistribute it and/or
  13  *              modify it under the terms of the GNU General Public License
  14  *              as published by the Free Software Foundation; either version
  15  *              2 of the License, or (at your option) any later version.
  16  *
  17  *              $Id: snmp.h,v 1.19 2001/06/14 13:40:46 davem Exp $
  18  *
  19  */
  20
  21 #ifndef _SNMP_H
  22 #define _SNMP_H
  23
  24 #include <linux/cache.h>
  25 #include <linux/snmp.h>
  26
  27 /*
  28  * Mibs are stored in array of unsigned long.
  29  */
  30 /*
  31  * struct snmp_mib{}
  32  *  - list of entries for particular API (such as /proc/net/snmp)
  33  *  - name of entries.
  34  */
  35 struct snmp_mib {
  36         char *name;
  37         int entry;
  38 };
  39
  40 #define SNMP_MIB_ITEM(_name,_entry)     {       \
  41         .name = _name,                          \
  42         .entry = _entry,                        \
  43 }
  44
  45 #define SNMP_MIB_SENTINEL {     \
  46         .name = NULL,           \
  47         .entry = 0,             \
  48 }
  49
  50 /*
  51  * We use all unsigned longs. Linux will soon be so reliable that even
  52  * these will rapidly get too small 8-). Seriously consider the IpInReceives
  53  * count on the 20Gb/s + networks people expect in a few years time!
  54  */
  55
  56 /*
  57  * The rule for padding:
  58  * Best is power of two because then the right structure can be found by a
  59  * simple shift. The structure should be always cache line aligned.
  60  * gcc needs n=alignto(cachelinesize, popcnt(sizeof(bla_mib))) shift/add
  61  * instructions to emulate multiply in case it is not power-of-two.
  62  * Currently n is always <=3 for all sizes so simple cache line alignment
  63  * is enough.
  64  *
  65  * The best solution would be a global CPU local area , especially on 64
  66  * and 128byte cacheline machine it makes a *lot* of sense -AK
  67  */
  68
  69 #define __SNMP_MIB_ALIGN__      ____cacheline_aligned
  70
  71 /* IPstats */
  72 #define IPSTATS_MIB_MAX __IPSTATS_MIB_MAX
  73 struct ipstats_mib {
  74         unsigned long   mibs[IPSTATS_MIB_MAX];
  75 } __SNMP_MIB_ALIGN__;
  76
  77 /* ICMP */
  78 #define ICMP_MIB_DUMMY  __ICMP_MIB_MAX
  79 #define ICMP_MIB_MAX    (__ICMP_MIB_MAX + 1)
  80
  81 struct icmp_mib {
  82         unsigned long   mibs[ICMP_MIB_MAX];
  83 } __SNMP_MIB_ALIGN__;
  84
  85 /* ICMP6 (IPv6-ICMP) */
  86 #define ICMP6_MIB_MAX   __ICMP6_MIB_MAX
  87 struct icmpv6_mib {
  88         unsigned long   mibs[ICMP6_MIB_MAX];
  89 } __SNMP_MIB_ALIGN__;
  90
  91 /* TCP */
  92 #define TCP_MIB_MAX     __TCP_MIB_MAX
  93 struct tcp_mib {
  94         unsigned long   mibs[TCP_MIB_MAX];
  95 } __SNMP_MIB_ALIGN__;
  96
  97 /* UDP */
  98 #define UDP_MIB_MAX     __UDP_MIB_MAX
  99 struct udp_mib {
 100         unsigned long   mibs[UDP_MIB_MAX];
 101 } __SNMP_MIB_ALIGN__;
 102
 103 /* Linux */
 104 #define LINUX_MIB_MAX   __LINUX_MIB_MAX
 105 struct linux_mib {
 106         unsigned long   mibs[LINUX_MIB_MAX];
 107 };
 108
 109
 110 /*
 111  * FIXME: On x86 and some other CPUs the split into user and softirq parts
 112  * is not needed because addl $1,memory is atomic against interrupts (but
 113  * atomic_inc would be overkill because of the lock cycles). Wants new
 114  * nonlocked_atomic_inc() primitives -AK
 115  */
 116 #define DEFINE_SNMP_STAT(type, name)    \
 117         __typeof__(type) *name[2]
 118 #define DECLARE_SNMP_STAT(type, name)   \
 119         extern __typeof__(type) *name[2]
 120
 121 #define SNMP_STAT_BHPTR(name)   (name[0])
 122 #define SNMP_STAT_USRPTR(name)  (name[1])
 123
 124 #define SNMP_INC_STATS_BH(mib, field)   \
 125         (per_cpu_ptr(mib[0], raw_smp_processor_id())->mibs[field]++)
 126 #define SNMP_INC_STATS_OFFSET_BH(mib, field, offset)    \
 127         (per_cpu_ptr(mib[0], raw_smp_processor_id())->mibs[field + (offset)]++)
 128 #define SNMP_INC_STATS_USER(mib, field) \
 129         (per_cpu_ptr(mib[1], raw_smp_processor_id())->mibs[field]++)
 130 #define SNMP_INC_STATS(mib, field)      \
 131         (per_cpu_ptr(mib[!in_softirq()], raw_smp_processor_id())->mibs[field]++)
 132 #define SNMP_DEC_STATS(mib, field)      \
 133         (per_cpu_ptr(mib[!in_softirq()], raw_smp_processor_id())->mibs[field]--)
 134 #define SNMP_ADD_STATS_BH(mib, field, addend)   \
 135         (per_cpu_ptr(mib[0], raw_smp_processor_id())->mibs[field] += addend)
 136 #define SNMP_ADD_STATS_USER(mib, field, addend)         \
 137         (per_cpu_ptr(mib[1], raw_smp_processor_id())->mibs[field] += addend)
 138
 139 #endif