Merge pull request 'Added logic to find next available IP address' (#1) from mike/add-ip-lookups into master

Reviewed-on: #1

configreader.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"fmt"
+	"io/fs"
+	"net"
+	"path/filepath"
+	"strings"
+
+	"gopkg.in/ini.v1"
+)
+
+func parseUsedIPsFromConfigs(dir string) ([]net.IP, error) {
+	var usedIPs []net.IP
+
+	err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
+		if err != nil || d.IsDir() || !strings.HasSuffix(d.Name(), ".conf") {
+			return nil
+		}
+
+		cfg, err := ini.Load(path)
+		if err != nil {
+			return fmt.Errorf("failed to parse config %s: %w", path, err)
+		}
+
+		// Check [Interface] section
+		if iface := cfg.Section("Interface"); iface != nil {
+			if addr := iface.Key("Address").String(); addr != "" {
+				ip := strings.Split(addr, "/")[0]
+				usedIPs = append(usedIPs, net.ParseIP(ip))
+			}
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	return usedIPs, nil
+}

go.mod

@@ -8,7 +8,9 @@ require (
 )
 
 require (
+	github.com/joho/godotenv v1.5.1 // indirect
 	github.com/pquerna/cachecontrol v0.2.0 // indirect
 	golang.org/x/crypto v0.37.0 // indirect
 	gopkg.in/go-jose/go-jose.v2 v2.6.3 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
 )

go.sum

@@ -4,6 +4,8 @@ github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pquerna/cachecontrol v0.2.0 h1:vBXSNuE5MYP9IJ5kjsdo8uq+w41jSPgvba2DEnkRx9k=
@@ -18,5 +20,7 @@ golang.org/x/oauth2 v0.29.0/go.mod h1:onh5ek6nERTohokkhCD/y2cV4Do3fxFHFuAejCkRWT
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/go-jose/go-jose.v2 v2.6.3 h1:nt80fvSDlhKWQgSWyHyy5CfmlQr+asih51R8PTWNKKs=
 gopkg.in/go-jose/go-jose.v2 v2.6.3/go.mod h1:zzZDPkNNw/c9IE7Z9jr11mBZQhKQTMzoEEIoEdZlFBI=
+gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
+gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

ipaddresses.go

@@ -0,0 +1,100 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+)
+
+func getInterfaceIPAndMask(interfaceName string) (ip net.IP, mask net.IPMask, err error) {
+	iface, err := net.InterfaceByName(interfaceName)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to get interface %s: %w", interfaceName, err)
+	}
+
+	addrs, err := iface.Addrs()
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to get addresses for %s: %w", interfaceName, err)
+	}
+
+	for _, addr := range addrs {
+		ipNet, ok := addr.(*net.IPNet)
+		if !ok || ipNet.IP.IsLoopback() || ipNet.IP.To4() == nil {
+			continue
+		}
+
+		return ipNet.IP, ipNet.Mask, nil
+	}
+
+	return nil, nil, fmt.Errorf("no valid IPv4 address found for interface %s", interfaceName)
+}
+
+func getNextFreeIP() (net.IP, error) {
+	var wg string = os.Getenv("WIREGUARD_INTERFACE")
+	ip, mask, err := getInterfaceIPAndMask(wg)
+	if err != nil {
+		log.Fatal(err)
+	}
+	used, err := parseUsedIPsFromConfigs("./configs")
+	if err != nil {
+		fmt.Println("Error:", err)
+		return nil, fmt.Errorf("Unkown err: %s", err)
+	}
+
+	for _, ip := range used {
+		fmt.Println("Used IP:", ip)
+	}
+	// used := []net.IP{
+	// 	net.ParseIP("10.200.34.1"),
+	// 	net.ParseIP("10.200.34.2"),
+	// 	net.ParseIP("10.200.34.3"),
+	// 	net.ParseIP("10.200.34.4"),
+	// 	net.ParseIP("10.200.34.5"),
+	// 	net.ParseIP("10.200.34.6"),
+	// 	net.ParseIP("10.200.34.225"),
+	// 	net.ParseIP("10.200.34.226"),
+	// 	net.ParseIP("10.200.34.227"),
+	// }
+
+	network := ip.Mask(mask)
+	ipNet := &net.IPNet{IP: network, Mask: mask}
+
+	// Turn the used list into a map for fast lookup
+	usedMap := make(map[string]bool)
+	for _, u := range used {
+		usedMap[u.String()] = true
+	}
+
+	// Get network boundaries
+	start := ipToUint32(network) + 1
+	end := ipToUint32(lastIP(ipNet)) - 1 // Skip broadcast
+
+	for i := start; i <= end; i++ {
+		candidate := uint32ToIP(i)
+		if !usedMap[candidate.String()] {
+			return candidate, nil
+		}
+	}
+
+	return nil, fmt.Errorf("no free IPs in subnet %s", ipNet.String())
+}
+
+func ipToUint32(ip net.IP) uint32 {
+	ip = ip.To4()
+	return uint32(ip[0])<<24 | uint32(ip[1])<<16 | uint32(ip[2])<<8 | uint32(ip[3])
+}
+
+func uint32ToIP(n uint32) net.IP {
+	return net.IPv4(byte(n>>24), byte(n>>16), byte(n>>8), byte(n))
+}
+
+func lastIP(ipNet *net.IPNet) net.IP {
+	ip := ipNet.IP.To4()
+	mask := ipNet.Mask
+	broadcast := make(net.IP, len(ip))
+	for i := range ip {
+		broadcast[i] = ip[i] | ^mask[i]
+	}
+	return broadcast
+}

main.go

@@ -5,12 +5,12 @@ import (
 	"fmt"
 	"log"
 	"net/http"
-	"strings"
 	"os"
+	"strings"
 
+	"github.com/coreos/go-oidc"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/microsoft"
-	"github.com/coreos/go-oidc"
 )
 
 var (
@@ -26,10 +26,16 @@ var (
 
 func main() {
 
+	nextIP, err := getNextFreeIP()
+	if err != nil {
+		fmt.Println("Error:", err)
+	} else {
+		fmt.Println("Next available IP:", nextIP)
+	}
+
 	ctx := context.Background()
 	issuer := fmt.Sprintf("https://login.microsoftonline.com/%s/v2.0", tenantID)
 
-	var err error
 	provider, err = oidc.NewProvider(ctx, issuer)
 	if err != nil {
 		log.Fatalf("failed to get provider: %v", err)
@@ -50,6 +56,7 @@ func main() {
 
 	log.Println("Server started at http://localhost:5000")
 	log.Fatal(http.ListenAndServe(":5000", nil))
+
 }
 
 func handleIndex(w http.ResponseWriter, r *http.Request) {
@@ -77,7 +84,7 @@ func handleIndex(w http.ResponseWriter, r *http.Request) {
 	}
 
 	var claims struct {
-		Email string `json:"email"`
+		Email             string `json:"email"`
 		PreferredUsername string `json:"preferred_username"`
 		Name              string `json:"name"`
 	}