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  */
  34 struct snmp_mib {
  35         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
  72 struct 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
  80 struct icmp_mib {
  81         unsigned long   mibs[ICMP_MIB_MAX];
  82 } __SNMP_MIB_ALIGN__;
  83
  84 #define ICMPMSG_MIB_MAX __ICMPMSG_MIB_MAX
  85 struct 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
  91 struct icmpv6_mib {
  92         unsigned long   mibs[ICMP6_MIB_MAX];
  93 } __SNMP_MIB_ALIGN__;
  94
  95 #define ICMP6MSG_MIB_MAX  __ICMP6MSG_MIB_MAX
  96 struct 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
 103 struct tcp_mib {
 104         unsigned long   mibs[TCP_MIB_MAX];
 105 } __SNMP_MIB_ALIGN__;
 106
 107 /* UDP */
 108 #define UDP_MIB_MAX     __UDP_MIB_MAX
 109 struct udp_mib {
 110         unsigned long   mibs[UDP_MIB_MAX];
 111 } __SNMP_MIB_ALIGN__;
 112
 113 /* Linux */
 114 #define LINUX_MIB_MAX   __LINUX_MIB_MAX
 115 struct linux_mib {
 116         unsigned long   mibs[LINUX_MIB_MAX];
 117 };
 118
 119 /* Linux Xfrm */
 120 #define LINUX_MIB_XFRMMAX       __LINUX_MIB_XFRMMAX
 121 struct 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) *name[2]
 133 #define DECLARE_SNMP_STAT(type, name)   \
 134         extern __typeof__(type) *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         (per_cpu_ptr(mib[0], raw_smp_processor_id())->mibs[field]++)
 141 #define SNMP_INC_STATS_USER(mib, field) \
 142         do { \
 143                 per_cpu_ptr(mib[1], get_cpu())->mibs[field]++; \
 144                 put_cpu(); \
 145         } while (0)
 146 #define SNMP_INC_STATS(mib, field)      \
 147         do { \
 148                 per_cpu_ptr(mib[!in_softirq()], get_cpu())->mibs[field]++; \
 149                 put_cpu(); \
 150         } while (0)
 151 #define SNMP_DEC_STATS(mib, field)      \
 152         do { \
 153                 per_cpu_ptr(mib[!in_softirq()], get_cpu())->mibs[field]--; \
 154                 put_cpu(); \
 155         } while (0)
 156 #define SNMP_ADD_STATS_BH(mib, field, addend)   \
 157         (per_cpu_ptr(mib[0], raw_smp_processor_id())->mibs[field] += addend)
 158 #define SNMP_ADD_STATS_USER(mib, field, addend)         \
 159         do { \
 160                 per_cpu_ptr(mib[1], get_cpu())->mibs[field] += addend; \
 161                 put_cpu(); \
 162         } while (0)
 163
 164 #endif