4 files changed, 195 insertions, 0 deletions
diff --git a/utils/go.mod b/utils/go.mod
new file mode 100644
index 0000000..0090185
--- /dev/null
+++ b/utils/go.mod
@@ -0,0 +1,5 @@
+module utils
+
+go 1.23
+
+require gopkg.in/yaml.v3 v3.0.1
diff --git a/utils/go.sum b/utils/go.sum
new file mode 100644
index 0000000..a62c313
--- /dev/null
+++ b/utils/go.sum
@@ -0,0 +1,4 @@
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/utils/main.go b/utils/main.go
new file mode 100644
index 0000000..db27e9c
--- /dev/null
+++ b/utils/main.go
@@ -0,0 +1,160 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/netip"
+	"os"
+	"utils/yaml_ipam"
+)
+
+func main() {
+	err := work()
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "Error reading file: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func work() error {
+	ipamYaml := "../ansible/group_vars/all/ipam.yml"
+	bs, err := os.ReadFile(ipamYaml)
+	if err != nil {
+		return err
+	}
+
+	ipam, err := loadIpam(bs)
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("digraph {\n")
+	//fmt.Printf(" layout=dot\n")
+	//fmt.Printf(" layout=twopi\n")
+	fmt.Printf(" layout=circo\n")
+	//fmt.Printf(" ranksep=3\n")
+	//fmt.Printf(" ratio=auto\n")
+	//fmt.Printf(" rankdir=LR\n")
+	//fmt.Printf(" rankdir=RL\n")
+	//fmt.Printf(" rankdir=TB\n")
+	fmt.Printf("\n")
+	fmt.Printf("  # Nodes\n")
+	for _, n := range ipam.networks {
+		fmt.Printf("  %s [ label = \"%s\\n%s\"];\n", n.name, n.name, n.prefix)
+	}
+	for _, n := range ipam.FindRoots() {
+		fmt.Printf("  %s [ root = true ];\n", n.name)
+	}
+
+	fmt.Printf("\n")
+	fmt.Printf("  # Relationships\n")
+	for _, n := range ipam.networks {
+		for _, c := range ipam.networks {
+			if c.parent == n {
+				fmt.Printf("   %s -> %s;\n", n.name, c.name)
+			}
+		}
+	}
+	fmt.Printf("}\n")
+
+	return nil
+}
+
+func loadIpam(bs []byte) (*Ipam, error) {
+	parsed, err := yaml_ipam.Parse(bs)
+	if err != nil {
+		return nil, err
+	}
+
+	ipam_, err := processNetworks(parsed.Ipam6.Networks)
+	if err != nil {
+		return nil, err
+	}
+
+	ipam_.ResolveParents()
+
+	return ipam_, nil
+}
+
+type Ipam struct {
+	networks []*Network
+}
+
+func (ipam *Ipam) ResolveParents() {
+	for _, n := range ipam.networks {
+		log.Printf("network %s/%s", n.name, n.prefix)
+		for _, p := range ipam.networks {
+			if n == p {
+				continue
+			}
+			//log.Printf("candidate %s/%s", p.name, p.prefix)
+			if p.prefix.Contains(n.prefix.Addr()) {
+				if n.parent == nil {
+					log.Printf("found parent %s/%s", p.name, p.prefix)
+					n.parent = p
+				} else {
+					if n.parent.prefix.Contains(p.prefix.Addr()) {
+						log.Printf("found better parent %s/%s", p.name, p.prefix)
+						n.parent = p
+					}
+				}
+			}
+		}
+	}
+
+	return
+}
+
+func (ipam *Ipam) FindRoots() []*Network {
+	var ns []*Network
+
+	for _, n := range ipam.networks {
+		if n.parent == nil {
+			ns = append(ns, n)
+		}
+	}
+
+	return ns
+}
+
+type Network struct {
+	name   string
+	parent *Network
+	prefix netip.Prefix
+	hosts  []networkHost
+}
+
+type networkHost struct {
+	name    string
+	address netip.Addr
+}
+
+func processNetworks(networks map[string]yaml_ipam.Network6Yaml) (*Ipam, error) {
+	var ns []*Network
+
+	for name, net := range networks {
+		log.Printf("Processing net %v\net", name)
+		prefix, err := netip.ParsePrefix(net.Range)
+		if err != nil {
+			return nil, fmt.Errorf("error parsing net range: %v\net", err)
+		}
+		log.Printf("prefix: %s", prefix.String())
+
+		n := Network{name: name, prefix: prefix}
+		for hostname, a := range net.Hosts {
+			addr, err := netip.ParseAddr(a)
+			if err != nil {
+				return nil, fmt.Errorf("network: %s, unable to parse host address %s\net", n.name, a)
+			}
+
+			n.hosts = append(n.hosts, networkHost{
+				name:    hostname,
+				address: addr,
+			})
+		}
+
+		ns = append(ns, &n)
+	}
+
+	return &Ipam{networks: ns}, nil
+}
diff --git a/utils/yaml_ipam/yaml_ipam.go b/utils/yaml_ipam/yaml_ipam.go
new file mode 100644
index 0000000..ff65155
--- /dev/null
+++ b/utils/yaml_ipam/yaml_ipam.go
@@ -0,0 +1,26 @@
+package yaml_ipam
+
+import "gopkg.in/yaml.v3"
+
+type Ipam struct {
+	Ipam6 Ipam6 `yaml:"ipam6"`
+}
+
+type Ipam6 struct {
+	Networks map[string]Network6Yaml `yaml:"networks"`
+}
+
+type Network6Yaml struct {
+	Range string            `yaml:"range"`
+	Hosts map[string]string `yaml:"hosts"`
+}
+
+func Parse(bs []byte) (Ipam, error) {
+	var ipam Ipam
+	err := yaml.Unmarshal(bs, &ipam)
+	if err != nil {
+		return Ipam{}, err
+	}
+
+	return ipam, nil
+}