1 files changed, 166 insertions, 0 deletions
diff --git a/src/go/collectors/go.d.plugin/modules/dnsmasq_dhcp/collect.go b/src/go/collectors/go.d.plugin/modules/dnsmasq_dhcp/collect.go
new file mode 100644
index 000000000..4d3e3ac5e
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/dnsmasq_dhcp/collect.go
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package dnsmasq_dhcp
+
+import (
+	"bufio"
+	"io"
+	"math"
+	"math/big"
+	"net"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/netdata/netdata/go/go.d.plugin/pkg/iprange"
+)
+
+func (d *DnsmasqDHCP) collect() (map[string]int64, error) {
+	now := time.Now()
+	var updated bool
+
+	if now.Sub(d.parseConfigTime) > d.parseConfigEvery {
+		d.parseConfigTime = now
+
+		dhcpRanges, dhcpHosts := d.parseDnsmasqDHCPConfiguration()
+		d.dhcpRanges, d.dhcpHosts = dhcpRanges, dhcpHosts
+		updated = d.updateCharts()
+
+		d.collectV4V6Stats()
+	}
+
+	f, err := os.Open(d.LeasesPath)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = f.Close() }()
+
+	if !updated {
+		fi, err := f.Stat()
+		if err != nil {
+			return nil, err
+		}
+
+		if d.leasesModTime.Equal(fi.ModTime()) {
+			d.Debug("lease database file modification time has not changed, old data is returned")
+			return d.mx, nil
+		}
+
+		d.Debug("leases db file modification time has changed, reading it")
+		d.leasesModTime = fi.ModTime()
+	}
+
+	leases := findLeases(f)
+	d.collectRangesStats(leases)
+
+	return d.mx, nil
+}
+
+func (d *DnsmasqDHCP) collectV4V6Stats() {
+	d.mx["ipv4_dhcp_ranges"], d.mx["ipv6_dhcp_ranges"] = 0, 0
+	for _, r := range d.dhcpRanges {
+		if r.Family() == iprange.V6Family {
+			d.mx["ipv6_dhcp_ranges"]++
+		} else {
+			d.mx["ipv4_dhcp_ranges"]++
+		}
+	}
+
+	d.mx["ipv4_dhcp_hosts"], d.mx["ipv6_dhcp_hosts"] = 0, 0
+	for _, ip := range d.dhcpHosts {
+		if ip.To4() == nil {
+			d.mx["ipv6_dhcp_hosts"]++
+		} else {
+			d.mx["ipv4_dhcp_hosts"]++
+		}
+	}
+}
+
+func (d *DnsmasqDHCP) collectRangesStats(leases []net.IP) {
+	for _, r := range d.dhcpRanges {
+		d.mx["dhcp_range_"+r.String()+"_allocated_leases"] = 0
+		d.mx["dhcp_range_"+r.String()+"_utilization"] = 0
+	}
+
+	for _, ip := range leases {
+		for _, r := range d.dhcpRanges {
+			if r.Contains(ip) {
+				d.mx["dhcp_range_"+r.String()+"_allocated_leases"]++
+				break
+			}
+		}
+	}
+
+	for _, ip := range d.dhcpHosts {
+		for _, r := range d.dhcpRanges {
+			if r.Contains(ip) {
+				d.mx["dhcp_range_"+r.String()+"_allocated_leases"]++
+				break
+			}
+		}
+	}
+
+	for _, r := range d.dhcpRanges {
+		name := "dhcp_range_" + r.String() + "_allocated_leases"
+		numOfIps, ok := d.mx[name]
+		if !ok {
+			d.mx[name] = 0
+		}
+		d.mx["dhcp_range_"+r.String()+"_utilization"] = int64(math.Round(calcPercent(numOfIps, r.Size())))
+	}
+}
+
+func (d *DnsmasqDHCP) updateCharts() bool {
+	var updated bool
+	seen := make(map[string]bool)
+	for _, r := range d.dhcpRanges {
+		seen[r.String()] = true
+		if !d.cacheDHCPRanges[r.String()] {
+			d.cacheDHCPRanges[r.String()] = true
+			d.addDHCPRangeCharts(r.String())
+			updated = true
+		}
+	}
+
+	for v := range d.cacheDHCPRanges {
+		if !seen[v] {
+			delete(d.cacheDHCPRanges, v)
+			d.removeDHCPRangeCharts(v)
+			updated = true
+		}
+	}
+	return updated
+}
+
+func findLeases(r io.Reader) []net.IP {
+	/*
+		1560300536 08:00:27:61:3c:ee 2.2.2.3 debian8 *
+		duid 00:01:00:01:24:90:cf:5b:08:00:27:61:2e:2c
+		1560300414 660684014 1234::20b * 00:01:00:01:24:90:cf:a3:08:00:27:61:3c:ee
+	*/
+	var ips []net.IP
+	s := bufio.NewScanner(r)
+
+	for s.Scan() {
+		parts := strings.Fields(s.Text())
+		if len(parts) != 5 {
+			continue
+		}
+
+		ip := net.ParseIP(parts[2])
+		if ip == nil {
+			continue
+		}
+		ips = append(ips, ip)
+	}
+
+	return ips
+}
+
+func calcPercent(ips int64, hosts *big.Int) float64 {
+	h := hosts.Int64()
+	if ips == 0 || h == 0 || !hosts.IsInt64() {
+		return 0
+	}
+	return float64(ips) * 100 / float64(h)
+}