/*
   *
   *		SNMP MIB entries for the IP subsystem.
   *		
   *		Alan Cox <gw4pts@gw4pts.ampr.org>
   *
   *		We don't chose to implement SNMP in the kernel (this would
   *		be silly as SNMP is a pain in the backside in places). We do
   *		however need to collect the MIB statistics and export them
   *		out of /proc (eventually)
   *
   *		This program is free software; you can redistribute it and/or
   *		modify it under the terms of the GNU General Public License
   *		as published by the Free Software Foundation; either version
   *		2 of the License, or (at your option) any later version.
   *

   */
   
  #ifndef _SNMP_H
  #define _SNMP_H
  
  #include <linux/cache.h>
  #include <linux/snmp.h>

  #include <linux/smp.h>

  
  /*
   * Mibs are stored in array of unsigned long.
   */
  /*
   * struct snmp_mib{}
   *  - list of entries for particular API (such as /proc/net/snmp)
   *  - name of entries.
   */
  struct snmp_mib {

  	const char *name;

  	int entry;
  };
  
  #define SNMP_MIB_ITEM(_name,_entry)	{	\
  	.name = _name,				\
  	.entry = _entry,			\
  }
  
  #define SNMP_MIB_SENTINEL {	\
  	.name = NULL,		\
  	.entry = 0,		\
  }
  
  /*

   * We use unsigned longs for most mibs but u64 for ipstats.

   */

  #include <linux/u64_stats_sync.h>

  /* IPstats */
  #define IPSTATS_MIB_MAX	__IPSTATS_MIB_MAX
  struct ipstats_mib {

  	/* mibs[] must be first field of struct ipstats_mib */
  	u64		mibs[IPSTATS_MIB_MAX];
  	struct u64_stats_sync syncp;

  };

  
  /* ICMP */

  #define ICMP_MIB_MAX	__ICMP_MIB_MAX

  struct icmp_mib {
  	unsigned long	mibs[ICMP_MIB_MAX];

  };

  #define ICMPMSG_MIB_MAX	__ICMPMSG_MIB_MAX
  struct icmpmsg_mib {

  	atomic_long_t	mibs[ICMPMSG_MIB_MAX];

  };

  /* ICMP6 (IPv6-ICMP) */
  #define ICMP6_MIB_MAX	__ICMP6_MIB_MAX

  /* per network ns counters */

  struct icmpv6_mib {
  	unsigned long	mibs[ICMP6_MIB_MAX];

  };

  /* per device counters, (shared on all cpus) */
  struct icmpv6_mib_device {
  	atomic_long_t	mibs[ICMP6_MIB_MAX];
  };

  #define ICMP6MSG_MIB_MAX  __ICMP6MSG_MIB_MAX

  /* per network ns counters */

  struct icmpv6msg_mib {

  	atomic_long_t	mibs[ICMP6MSG_MIB_MAX];

  };

  /* per device counters, (shared on all cpus) */
  struct icmpv6msg_mib_device {
  	atomic_long_t	mibs[ICMP6MSG_MIB_MAX];
  };

  /* TCP */
  #define TCP_MIB_MAX	__TCP_MIB_MAX
  struct tcp_mib {
  	unsigned long	mibs[TCP_MIB_MAX];

  };

  
  /* UDP */
  #define UDP_MIB_MAX	__UDP_MIB_MAX
  struct udp_mib {
  	unsigned long	mibs[UDP_MIB_MAX];

  };

  /* Linux */
  #define LINUX_MIB_MAX	__LINUX_MIB_MAX
  struct linux_mib {
  	unsigned long	mibs[LINUX_MIB_MAX];
  };

  /* Linux Xfrm */
  #define LINUX_MIB_XFRMMAX	__LINUX_MIB_XFRMMAX
  struct linux_xfrm_mib {
  	unsigned long	mibs[LINUX_MIB_XFRMMAX];
  };

  #define SNMP_ARRAY_SZ 1

  #define DEFINE_SNMP_STAT(type, name)	\

  	__typeof__(type) __percpu *name[SNMP_ARRAY_SZ]

  #define DEFINE_SNMP_STAT_ATOMIC(type, name)	\
  	__typeof__(type) *name

  #define DECLARE_SNMP_STAT(type, name)	\

  	extern __typeof__(type) __percpu *name[SNMP_ARRAY_SZ]

  #define SNMP_INC_STATS_BH(mib, field)	\
  			__this_cpu_inc(mib[0]->mibs[field])

  #define SNMP_INC_STATS_USER(mib, field)	\

  			this_cpu_inc(mib[0]->mibs[field])

  #define SNMP_INC_STATS_ATOMIC_LONG(mib, field)	\
  			atomic_long_inc(&mib->mibs[field])

  #define SNMP_INC_STATS(mib, field)	\

  			this_cpu_inc(mib[0]->mibs[field])

  #define SNMP_DEC_STATS(mib, field)	\

  			this_cpu_dec(mib[0]->mibs[field])

  #define SNMP_ADD_STATS_BH(mib, field, addend)	\
  			__this_cpu_add(mib[0]->mibs[field], addend)

  #define SNMP_ADD_STATS_USER(mib, field, addend)	\

  			this_cpu_add(mib[0]->mibs[field], addend)

  #define SNMP_ADD_STATS(mib, field, addend)	\

  			this_cpu_add(mib[0]->mibs[field], addend)

  /*
   * Use "__typeof__(*mib[0]) *ptr" instead of "__typeof__(mib[0]) ptr"
   * to make @ptr a non-percpu pointer.
   */

  #define SNMP_UPD_PO_STATS(mib, basefield, addend)	\
  	do { \

  		this_cpu_inc(mib[0]->mibs[basefield##PKTS]);		\
  		this_cpu_add(mib[0]->mibs[basefield##OCTETS], addend);	\

  	} while (0)
  #define SNMP_UPD_PO_STATS_BH(mib, basefield, addend)	\
  	do { \

  		__this_cpu_inc(mib[0]->mibs[basefield##PKTS]);		\
  		__this_cpu_add(mib[0]->mibs[basefield##OCTETS], addend);	\

  	} while (0)

  
  
  #if BITS_PER_LONG==32
  
  #define SNMP_ADD_STATS64_BH(mib, field, addend) 			\
  	do {								\
  		__typeof__(*mib[0]) *ptr = __this_cpu_ptr((mib)[0]);	\
  		u64_stats_update_begin(&ptr->syncp);			\
  		ptr->mibs[field] += addend;				\
  		u64_stats_update_end(&ptr->syncp);			\
  	} while (0)

  #define SNMP_ADD_STATS64_USER(mib, field, addend) 			\
  	do {								\

  		local_bh_disable();					\
  		SNMP_ADD_STATS64_BH(mib, field, addend);		\
  		local_bh_enable();					\

  	} while (0)

  #define SNMP_ADD_STATS64(mib, field, addend)				\

  		SNMP_ADD_STATS64_USER(mib, field, addend)

  #define SNMP_INC_STATS64_BH(mib, field) SNMP_ADD_STATS64_BH(mib, field, 1)
  #define SNMP_INC_STATS64_USER(mib, field) SNMP_ADD_STATS64_USER(mib, field, 1)
  #define SNMP_INC_STATS64(mib, field) SNMP_ADD_STATS64(mib, field, 1)

  #define SNMP_UPD_PO_STATS64_BH(mib, basefield, addend)			\
  	do {								\
  		__typeof__(*mib[0]) *ptr;				\

  		ptr = __this_cpu_ptr((mib)[0]);				\

  		u64_stats_update_begin(&ptr->syncp);			\
  		ptr->mibs[basefield##PKTS]++;				\
  		ptr->mibs[basefield##OCTETS] += addend;			\
  		u64_stats_update_end(&ptr->syncp);			\
  	} while (0)

  #define SNMP_UPD_PO_STATS64(mib, basefield, addend)			\
  	do {								\
  		local_bh_disable();					\
  		SNMP_UPD_PO_STATS64_BH(mib, basefield, addend);		\
  		local_bh_enable();					\
  	} while (0)

  #else
  #define SNMP_INC_STATS64_BH(mib, field)		SNMP_INC_STATS_BH(mib, field)
  #define SNMP_INC_STATS64_USER(mib, field)	SNMP_INC_STATS_USER(mib, field)
  #define SNMP_INC_STATS64(mib, field)		SNMP_INC_STATS(mib, field)
  #define SNMP_DEC_STATS64(mib, field)		SNMP_DEC_STATS(mib, field)
  #define SNMP_ADD_STATS64_BH(mib, field, addend) SNMP_ADD_STATS_BH(mib, field, addend)
  #define SNMP_ADD_STATS64_USER(mib, field, addend) SNMP_ADD_STATS_USER(mib, field, addend)
  #define SNMP_ADD_STATS64(mib, field, addend)	SNMP_ADD_STATS(mib, field, addend)
  #define SNMP_UPD_PO_STATS64(mib, basefield, addend) SNMP_UPD_PO_STATS(mib, basefield, addend)
  #define SNMP_UPD_PO_STATS64_BH(mib, basefield, addend) SNMP_UPD_PO_STATS_BH(mib, basefield, addend)
  #endif

  #endif