LXR linux/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 */
  18 
  19#ifndef _SNMP_H
  20#define _SNMP_H
  21
  22#include <linux/cache.h>
  23#include <linux/snmp.h>
  24#include <linux/smp.h>
  25
  26/*
  27 * Mibs are stored in array of unsigned long.
  28 */
  29/*
  30 * struct snmp_mib{}
  31 *  - list of entries for particular API (such as /proc/net/snmp)
  32 *  - name of entries.
  33 */
  34struct snmp_mib {
  35        const char *name;
  36        int entry;
  37};
  38
  39#define SNMP_MIB_ITEM(_name,_entry)     {       \
  40        .name = _name,                          \
  41        .entry = _entry,                        \
  42}
  43
  44#define SNMP_MIB_SENTINEL {     \
  45        .name = NULL,           \
  46        .entry = 0,             \
  47}
  48
  49/*
  50 * We use all unsigned longs. Linux will soon be so reliable that even 
  51 * these will rapidly get too small 8-). Seriously consider the IpInReceives 
  52 * count on the 20Gb/s + networks people expect in a few years time!
  53 */
  54
  55/* 
  56 * The rule for padding: 
  57 * Best is power of two because then the right structure can be found by a 
  58 * simple shift. The structure should be always cache line aligned.
  59 * gcc needs n=alignto(cachelinesize, popcnt(sizeof(bla_mib))) shift/add 
  60 * instructions to emulate multiply in case it is not power-of-two. 
  61 * Currently n is always <=3 for all sizes so simple cache line alignment 
  62 * is enough. 
  63 * 
  64 * The best solution would be a global CPU local area , especially on 64 
  65 * and 128byte cacheline machine it makes a *lot* of sense -AK
  66 */ 
  67
  68#define __SNMP_MIB_ALIGN__      ____cacheline_aligned
  69
  70/* IPstats */
  71#define IPSTATS_MIB_MAX __IPSTATS_MIB_MAX
  72struct ipstats_mib {
  73        unsigned long   mibs[IPSTATS_MIB_MAX];
  74} __SNMP_MIB_ALIGN__;
  75
  76/* ICMP */
  77#define ICMP_MIB_DUMMY  __ICMP_MIB_MAX
  78#define ICMP_MIB_MAX    (__ICMP_MIB_MAX + 1)
  79
  80struct icmp_mib {
  81        unsigned long   mibs[ICMP_MIB_MAX];
  82} __SNMP_MIB_ALIGN__;
  83
  84#define ICMPMSG_MIB_MAX __ICMPMSG_MIB_MAX
  85struct icmpmsg_mib {
  86        unsigned long   mibs[ICMPMSG_MIB_MAX];
  87} __SNMP_MIB_ALIGN__;
  88
  89/* ICMP6 (IPv6-ICMP) */
  90#define ICMP6_MIB_MAX   __ICMP6_MIB_MAX
  91struct icmpv6_mib {
  92        unsigned long   mibs[ICMP6_MIB_MAX];
  93} __SNMP_MIB_ALIGN__;
  94
  95#define ICMP6MSG_MIB_MAX  __ICMP6MSG_MIB_MAX
  96struct icmpv6msg_mib {
  97        unsigned long   mibs[ICMP6MSG_MIB_MAX];
  98} __SNMP_MIB_ALIGN__;
  99
 100
 101/* TCP */
 102#define TCP_MIB_MAX     __TCP_MIB_MAX
 103struct tcp_mib {
 104        unsigned long   mibs[TCP_MIB_MAX];
 105} __SNMP_MIB_ALIGN__;
 106
 107/* UDP */
 108#define UDP_MIB_MAX     __UDP_MIB_MAX
 109struct udp_mib {
 110        unsigned long   mibs[UDP_MIB_MAX];
 111} __SNMP_MIB_ALIGN__;
 112
 113/* Linux */
 114#define LINUX_MIB_MAX   __LINUX_MIB_MAX
 115struct linux_mib {
 116        unsigned long   mibs[LINUX_MIB_MAX];
 117};
 118
 119/* Linux Xfrm */
 120#define LINUX_MIB_XFRMMAX       __LINUX_MIB_XFRMMAX
 121struct linux_xfrm_mib {
 122        unsigned long   mibs[LINUX_MIB_XFRMMAX];
 123};
 124
 125/* 
 126 * FIXME: On x86 and some other CPUs the split into user and softirq parts
 127 * is not needed because addl $1,memory is atomic against interrupts (but 
 128 * atomic_inc would be overkill because of the lock cycles). Wants new 
 129 * nonlocked_atomic_inc() primitives -AK
 130 */ 
 131#define DEFINE_SNMP_STAT(type, name)    \
 132        __typeof__(type) __percpu *name[2]
 133#define DECLARE_SNMP_STAT(type, name)   \
 134        extern __typeof__(type) __percpu *name[2]
 135
 136#define SNMP_STAT_BHPTR(name)   (name[0])
 137#define SNMP_STAT_USRPTR(name)  (name[1])
 138
 139#define SNMP_INC_STATS_BH(mib, field)   \
 140                        __this_cpu_inc(mib[0]->mibs[field])
 141#define SNMP_INC_STATS_USER(mib, field) \
 142                        this_cpu_inc(mib[1]->mibs[field])
 143#define SNMP_INC_STATS(mib, field)      \
 144                        this_cpu_inc(mib[!in_softirq()]->mibs[field])
 145#define SNMP_DEC_STATS(mib, field)      \
 146                        this_cpu_dec(mib[!in_softirq()]->mibs[field])
 147#define SNMP_ADD_STATS_BH(mib, field, addend)   \
 148                        __this_cpu_add(mib[0]->mibs[field], addend)
 149#define SNMP_ADD_STATS_USER(mib, field, addend) \
 150                        this_cpu_add(mib[1]->mibs[field], addend)
 151/*
 152 * Use "__typeof__(*mib[0]) *ptr" instead of "__typeof__(mib[0]) ptr"
 153 * to make @ptr a non-percpu pointer.
 154 */
 155#define SNMP_UPD_PO_STATS(mib, basefield, addend)       \
 156        do { \
 157                __typeof__(*mib[0]) *ptr; \
 158                preempt_disable(); \
 159                ptr = this_cpu_ptr((mib)[!in_softirq()]); \
 160                ptr->mibs[basefield##PKTS]++; \
 161                ptr->mibs[basefield##OCTETS] += addend;\
 162                preempt_enable(); \
 163        } while (0)
 164#define SNMP_UPD_PO_STATS_BH(mib, basefield, addend)    \
 165        do { \
 166                __typeof__(*mib[0]) *ptr = \
 167                        __this_cpu_ptr((mib)[!in_softirq()]); \
 168                ptr->mibs[basefield##PKTS]++; \
 169                ptr->mibs[basefield##OCTETS] += addend;\
 170        } while (0)
 171#endif
 172