[09/10,net-next] net:ipv4:proc: Introduce proc files for ipv4 per interface stats

diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 3569d8e..c6202d9 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -128,6 +128,14 @@  static const struct snmp_mib snmp4_ipextstats_list[] = {
 	SNMP_MIB_SENTINEL
 };
 
+static const struct snmp_mib snmp4_icmp_list[] = {
+	SNMP_MIB_ITEM("InMsgs", ICMP_MIB_INMSGS),
+	SNMP_MIB_ITEM("InErrors", ICMP_MIB_INERRORS),
+	SNMP_MIB_ITEM("OutMsgs", ICMP_MIB_OUTMSGS),
+	SNMP_MIB_ITEM("OutErrors", ICMP_MIB_OUTERRORS),
+	SNMP_MIB_SENTINEL
+};
+
 static const struct {
 	const char *name;
 	int index;
@@ -459,6 +467,113 @@  static const struct file_operations netstat_seq_fops = {
 	.release = single_release_net,
 };
 
+static void snmp_seq_show_item(struct seq_file *seq, void __percpu **pcpumib,
+				atomic_long_t *smib,
+				const struct snmp_mib *itemlist,
+				char *prefix)
+{
+	char name[32];
+	int i;
+	unsigned long val;
+
+	for (i = 0; itemlist[i].name; i++) {
+		val = pcpumib ?
+			snmp_fold_field64(pcpumib, itemlist[i].entry,
+				offsetof(struct ipstats_mib, syncp)) :
+			atomic_long_read(smib + itemlist[i].entry);
+		snprintf(name, sizeof(name), "%s%s",
+				prefix, itemlist[i].name);
+		seq_printf(seq, "%-32s\t%lu\n", name, val);
+	}
+}
+
+static void snmp_seq_show_icmpmsg(struct seq_file *seq, atomic_long_t *smib)
+{
+	char name[32];
+	int i;
+	unsigned long val;
+	for (i = 0; i < ICMPMSG_MIB_MAX; i++) {		
+		val = atomic_long_read(smib + i);
+		if (val) {
+			snprintf(name, sizeof(name), "Icmp%sType%u",
+				i & 0x100 ? "Out" : "In", i & 0xff);
+			seq_printf(seq, "%-32s\t%lu\n", name, val);
+		}
+	}
+}
+
+static int snmp_dev_seq_show(struct seq_file *seq, void *v)
+{
+	struct in_device *idev = (struct in_device *)seq->private;
+
+	seq_printf(seq, "%-32s\t%u\n", "ifIndex", idev->dev->ifindex);
+	seq_printf(seq, "%-32s\t%u\n", "Forwarding",
+		IN_DEV_FORWARD(idev));
+	seq_printf(seq, "%-32s\t%u\n", "McForwarding",
+		IN_DEV_MFORWARD(idev));
+	seq_printf(seq, "%-32s\t%u\n", "DefaultTTL",
+		   sysctl_ip_default_ttl);
+
+	BUILD_BUG_ON(offsetof(struct ipstats_mib, mibs) != 0);
+
+	snmp_seq_show_item(seq, (void __percpu **)idev->stats.ip, NULL,
+				snmp4_ipstats_list, "Ip");
+	snmp_seq_show_item(seq, (void __percpu **)idev->stats.ip, NULL,
+				snmp4_ipextstats_list, "Ip");
+	snmp_seq_show_item(seq, NULL, idev->stats.icmpdev->mibs,
+				snmp4_icmp_list, "Icmp");
+	snmp_seq_show_icmpmsg(seq, idev->stats.icmpmsgdev->mibs);
+	return 0;
+}
+
+static int snmp_dev_seq_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, snmp_dev_seq_show, PDE(inode)->data);
+}
+
+static const struct file_operations snmp_dev_seq_fops = {
+	.owner   = THIS_MODULE,
+	.open    = snmp_dev_seq_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = single_release,
+};
+
+int snmp_register_dev(struct in_device *idev)
+{
+	struct proc_dir_entry *p;
+	struct net *net;
+
+	if (!idev || !idev->dev)
+		return -EINVAL;
+
+	net = dev_net(idev->dev);
+	if (!net->mib.proc_net_devsnmp)
+		return -ENOENT;
+
+	p = proc_create_data(idev->dev->name, S_IRUGO,
+			net->mib.proc_net_devsnmp,
+			&snmp_dev_seq_fops, idev);
+	if (!p) 
+		return -ENOMEM;
+
+	idev->stats.proc_dir_entry = p;
+	return 0;
+}
+
+int snmp_unregister_dev(struct in_device *idev)
+{
+	struct net *net = dev_net(idev->dev);
+	if (!net->mib.proc_net_devsnmp)
+		return -ENOENT;
+	if (!idev->stats.proc_dir_entry)
+		return -EINVAL;
+	remove_proc_entry(idev->stats.proc_dir_entry->name,
+		net->mib.proc_net_devsnmp);
+	idev->stats.proc_dir_entry = NULL;
+	return 0;
+}
+
 static __net_init int ip_proc_init_net(struct net *net)
 {
 	if (!proc_net_fops_create(net, "sockstat", S_IRUGO, &sockstat_seq_fops))
@@ -467,9 +582,14 @@  static __net_init int ip_proc_init_net(struct net *net)
 		goto out_netstat;
 	if (!proc_net_fops_create(net, "snmp", S_IRUGO, &snmp_seq_fops))
 		goto out_snmp;
+	net->mib.proc_net_devsnmp = proc_mkdir("dev_snmp", net->proc_net);
+	if (!net->mib.proc_net_devsnmp)
+		goto out_dev_snmp;
 
 	return 0;
 
+out_dev_snmp:
+	proc_net_remove(net, "snmp");
 out_snmp:
 	proc_net_remove(net, "netstat");
 out_netstat:
@@ -483,6 +603,7 @@  static __net_exit void ip_proc_exit_net(struct net *net)
 	proc_net_remove(net, "snmp");
 	proc_net_remove(net, "netstat");
 	proc_net_remove(net, "sockstat");
+	proc_net_remove(net, "dev_snmp");
 }
 
 static __net_initdata struct pernet_operations ip_proc_ops = {