[IPV4]: Add ICMPMsgStats MIB (RFC 4293)

Background: RFC 4293 deprecates existing individual, named ICMP
type counters to be replaced with the ICMPMsgStatsTable. This table
includes entries for both IPv4 and IPv6, and requires counting of all
ICMP types, whether or not the machine implements the type.

These patches "remove" (but not really) the existing counters, and
replace them with the ICMPMsgStats tables for v4 and v6.
It includes the named counters in the /proc places they were, but gets the
values for them from the new tables. It also counts packets generated
from raw socket output (e.g., OutEchoes, MLD queries, RA's from
radvd, etc).

Changes:
1) create icmpmsg_statistics mib
2) create icmpv6msg_statistics mib
3) modify existing counters to use these
4) modify /proc/net/snmp to add "IcmpMsg" with all ICMP types
        listed by number for easy SNMP parsing
5) modify /proc/net/snmp printing for "Icmp" to get the named data
        from new counters.

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/snmp.h

@@ -82,6 +82,8 @@ enum
 	__ICMP_MIB_MAX
 };
 
+#define __ICMPMSG_MIB_MAX 512	/* Out+In for all 8-bit ICMP types */
+
 /* icmp6 mib definitions */
 /*
  * RFC 2466:  ICMPv6-MIB

include/net/icmp.h

@@ -30,9 +30,16 @@ struct icmp_err {
 
 extern struct icmp_err icmp_err_convert[];
 DECLARE_SNMP_STAT(struct icmp_mib, icmp_statistics);
+DECLARE_SNMP_STAT(struct icmpmsg_mib, icmpmsg_statistics);
 #define ICMP_INC_STATS(field)		SNMP_INC_STATS(icmp_statistics, field)
 #define ICMP_INC_STATS_BH(field)	SNMP_INC_STATS_BH(icmp_statistics, field)
 #define ICMP_INC_STATS_USER(field) 	SNMP_INC_STATS_USER(icmp_statistics, field)
+#define ICMPMSGOUT_INC_STATS(field)	SNMP_INC_STATS(icmpmsg_statistics, field+256)
+#define ICMPMSGOUT_INC_STATS_BH(field)	SNMP_INC_STATS_BH(icmpmsg_statistics, field+256)
+#define ICMPMSGOUT_INC_STATS_USER(field) 	SNMP_INC_STATS_USER(icmpmsg_statistics, field+256)
+#define ICMPMSGIN_INC_STATS(field)	SNMP_INC_STATS(icmpmsg_statistics, field)
+#define ICMPMSGIN_INC_STATS_BH(field)	SNMP_INC_STATS_BH(icmpmsg_statistics, field)
+#define ICMPMSGIN_INC_STATS_USER(field) SNMP_INC_STATS_USER(icmpmsg_statistics, field)
 
 struct dst_entry;
 struct net_proto_family;
@@ -42,6 +49,7 @@ extern void	icmp_send(struct sk_buff *skb_in,  int type, int code, __be32 info);
 extern int	icmp_rcv(struct sk_buff *skb);
 extern int	icmp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 extern void	icmp_init(struct net_proto_family *ops);
+extern void	icmp_out_count(unsigned char type);
 
 /* Move into dst.h ? */
 extern int 	xrlim_allow(struct dst_entry *dst, int timeout);

include/net/snmp.h

@@ -82,6 +82,11 @@ struct icmp_mib {
 	unsigned long	mibs[ICMP_MIB_MAX];
 } __SNMP_MIB_ALIGN__;
 
+#define ICMPMSG_MIB_MAX	__ICMPMSG_MIB_MAX
+struct icmpmsg_mib {
+	unsigned long	mibs[ICMPMSG_MIB_MAX];
+} __SNMP_MIB_ALIGN__;
+
 /* ICMP6 (IPv6-ICMP) */
 #define ICMP6_MIB_MAX	__ICMP6_MIB_MAX
 struct icmpv6_mib {

net/ipv4/af_inet.c

@@ -1302,6 +1302,10 @@ static int __init init_ipv4_mibs(void)
 			  sizeof(struct icmp_mib),
 			  __alignof__(struct icmp_mib)) < 0)
 		goto err_icmp_mib;
+	if (snmp_mib_init((void **)icmpmsg_statistics,
+			  sizeof(struct icmpmsg_mib),
+			  __alignof__(struct icmpmsg_mib)) < 0)
+		goto err_icmpmsg_mib;
 	if (snmp_mib_init((void **)tcp_statistics,
 			  sizeof(struct tcp_mib),
 			  __alignof__(struct tcp_mib)) < 0)
@@ -1324,6 +1328,8 @@ static int __init init_ipv4_mibs(void)
 err_udp_mib:
 	snmp_mib_free((void **)tcp_statistics);
 err_tcp_mib:
+	snmp_mib_free((void **)icmpmsg_statistics);
+err_icmpmsg_mib:
 	snmp_mib_free((void **)icmp_statistics);
 err_icmp_mib:
 	snmp_mib_free((void **)ip_statistics);

net/ipv4/icmp.c

@@ -115,6 +115,7 @@ struct icmp_bxm {
  *	Statistics
  */
 DEFINE_SNMP_STAT(struct icmp_mib, icmp_statistics) __read_mostly;
+DEFINE_SNMP_STAT(struct icmpmsg_mib, icmpmsg_statistics) __read_mostly;
 
 /* An array of errno for error messages from dest unreach. */
 /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
@@ -214,8 +215,6 @@ int sysctl_icmp_errors_use_inbound_ifaddr __read_mostly;
  */
 
 struct icmp_control {
-	int output_entry;	/* Field for increment on output */
-	int input_entry;	/* Field for increment on input */
 	void (*handler)(struct sk_buff *skb);
 	short   error;		/* This ICMP is classed as an error message */
 };
@@ -316,12 +315,10 @@ static inline int icmpv4_xrlim_allow(struct rtable *rt, int type, int code)
 /*
  *	Maintain the counters used in the SNMP statistics for outgoing ICMP
  */
-static void icmp_out_count(int type)
+void icmp_out_count(unsigned char type)
 {
-	if (type <= NR_ICMP_TYPES) {
-		ICMP_INC_STATS(icmp_pointers[type].output_entry);
-		ICMP_INC_STATS(ICMP_MIB_OUTMSGS);
-	}
+	ICMPMSGOUT_INC_STATS(type);
+	ICMP_INC_STATS(ICMP_MIB_OUTMSGS);
 }
 
 /*
@@ -390,7 +387,6 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
 		return;
 
 	icmp_param->data.icmph.checksum = 0;
-	icmp_out_count(icmp_param->data.icmph.type);
 
 	inet->tos = ip_hdr(skb)->tos;
 	daddr = ipc.addr = rt->rt_src;
@@ -952,6 +948,7 @@ int icmp_rcv(struct sk_buff *skb)
 
 	icmph = icmp_hdr(skb);
 
+	ICMPMSGIN_INC_STATS_BH(icmph->type);
 	/*
 	 *	18 is the highest 'known' ICMP type. Anything else is a mystery
 	 *
@@ -986,7 +983,6 @@ int icmp_rcv(struct sk_buff *skb)
 		}
 	}
 
-	ICMP_INC_STATS_BH(icmp_pointers[icmph->type].input_entry);
 	icmp_pointers[icmph->type].handler(skb);
 
 drop:
@@ -1002,109 +998,71 @@ int icmp_rcv(struct sk_buff *skb)
  */
 static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
 	[ICMP_ECHOREPLY] = {
-		.output_entry = ICMP_MIB_OUTECHOREPS,
-		.input_entry = ICMP_MIB_INECHOREPS,
 		.handler = icmp_discard,
 	},
 	[1] = {
-		.output_entry = ICMP_MIB_DUMMY,
-		.input_entry = ICMP_MIB_INERRORS,
 		.handler = icmp_discard,
 		.error = 1,
 	},
 	[2] = {
-		.output_entry = ICMP_MIB_DUMMY,
-		.input_entry = ICMP_MIB_INERRORS,
 		.handler = icmp_discard,
 		.error = 1,
 	},
 	[ICMP_DEST_UNREACH] = {
-		.output_entry = ICMP_MIB_OUTDESTUNREACHS,
-		.input_entry = ICMP_MIB_INDESTUNREACHS,
 		.handler = icmp_unreach,
 		.error = 1,
 	},
 	[ICMP_SOURCE_QUENCH] = {
-		.output_entry = ICMP_MIB_OUTSRCQUENCHS,
-		.input_entry = ICMP_MIB_INSRCQUENCHS,
 		.handler = icmp_unreach,
 		.error = 1,
 	},
 	[ICMP_REDIRECT] = {
-		.output_entry = ICMP_MIB_OUTREDIRECTS,
-		.input_entry = ICMP_MIB_INREDIRECTS,
 		.handler = icmp_redirect,
 		.error = 1,
 	},
 	[6] = {
-		.output_entry = ICMP_MIB_DUMMY,
-		.input_entry = ICMP_MIB_INERRORS,
 		.handler = icmp_discard,
 		.error = 1,
 	},
 	[7] = {
-		.output_entry = ICMP_MIB_DUMMY,
-		.input_entry = ICMP_MIB_INERRORS,
 		.handler = icmp_discard,
 		.error = 1,
 	},
 	[ICMP_ECHO] = {
-		.output_entry = ICMP_MIB_OUTECHOS,
-		.input_entry = ICMP_MIB_INECHOS,
 		.handler = icmp_echo,
 	},
 	[9] = {
-		.output_entry = ICMP_MIB_DUMMY,
-		.input_entry = ICMP_MIB_INERRORS,
 		.handler = icmp_discard,
 		.error = 1,
 	},
 	[10] = {
-		.output_entry = ICMP_MIB_DUMMY,
-		.input_entry = ICMP_MIB_INERRORS,
 		.handler = icmp_discard,
 		.error = 1,
 	},
 	[ICMP_TIME_EXCEEDED] = {
-		.output_entry = ICMP_MIB_OUTTIMEEXCDS,
-		.input_entry = ICMP_MIB_INTIMEEXCDS,
 		.handler = icmp_unreach,
 		.error = 1,
 	},
 	[ICMP_PARAMETERPROB] = {
-		.output_entry = ICMP_MIB_OUTPARMPROBS,
-		.input_entry = ICMP_MIB_INPARMPROBS,
 		.handler = icmp_unreach,
 		.error = 1,
 	},
 	[ICMP_TIMESTAMP] = {
-		.output_entry = ICMP_MIB_OUTTIMESTAMPS,
-		.input_entry = ICMP_MIB_INTIMESTAMPS,
 		.handler = icmp_timestamp,
 	},
 	[ICMP_TIMESTAMPREPLY] = {
-		.output_entry = ICMP_MIB_OUTTIMESTAMPREPS,
-		.input_entry = ICMP_MIB_INTIMESTAMPREPS,
 		.handler = icmp_discard,
 	},
 	[ICMP_INFO_REQUEST] = {
-		.output_entry = ICMP_MIB_DUMMY,
-		.input_entry = ICMP_MIB_DUMMY,
 		.handler = icmp_discard,
 	},
 	[ICMP_INFO_REPLY] = {
-		.output_entry = ICMP_MIB_DUMMY,
-		.input_entry = ICMP_MIB_DUMMY,
 		.handler = icmp_discard,
 	},
 	[ICMP_ADDRESS] = {
-		.output_entry = ICMP_MIB_OUTADDRMASKS,
-		.input_entry = ICMP_MIB_INADDRMASKS,
 		.handler = icmp_address,
 	},
 	[ICMP_ADDRESSREPLY] = {
-		.output_entry = ICMP_MIB_OUTADDRMASKREPS,
-		.input_entry = ICMP_MIB_INADDRMASKREPS,
 		.handler = icmp_address_reply,
 	},
 };
@@ -1146,4 +1104,5 @@ void __init icmp_init(struct net_proto_family *ops)
 EXPORT_SYMBOL(icmp_err_convert);
 EXPORT_SYMBOL(icmp_send);
 EXPORT_SYMBOL(icmp_statistics);
+EXPORT_SYMBOL(icmpmsg_statistics);
 EXPORT_SYMBOL(xrlim_allow);

net/ipv4/ip_output.c

@@ -1261,6 +1261,10 @@ int ip_push_pending_frames(struct sock *sk)
 	skb->priority = sk->sk_priority;
 	skb->dst = dst_clone(&rt->u.dst);
 
+	if (iph->protocol == IPPROTO_ICMP)
+		icmp_out_count(((struct icmphdr *)
+			skb_transport_header(skb))->type);
+
 	/* Netfilter gets whole the not fragmented skb. */
 	err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL,
 		      skb->dst->dev, dst_output);