Subnet range selector, interface fixes (#481)

README.md

@@ -42,6 +42,7 @@ docker-compose up
 | `BIND_ADDRESS`              | The addresses that can access to the web interface and the port, use unix:///abspath/to/file.socket for unix domain socket.                                                 | 0.0.0.0:80                         |
 | `SESSION_SECRET`            | The secret key used to encrypt the session cookies. Set this to a random value                                                                                              | N/A                                |
 | `SESSION_SECRET_FILE`       | Optional filepath for the secret key used to encrypt the session cookies. Leave `SESSION_SECRET` blank to take effect                                                       | N/A                                |
+| `SUBNET_RANGES`             | The list of address subdivision ranges. Format: `SR Name:10.0.1.0/24; SR2:10.0.2.0/24,10.0.3.0/24` Each CIDR must be inside one of the server interfaces.                   | N/A                                |
 | `WGUI_USERNAME`             | The username for the login page. Used for db initialization only                                                                                                            | `admin`                            |
 | `WGUI_PASSWORD`             | The password for the user on the login page. Will be hashed automatically. Used for db initialization only                                                                  | `admin`                            |
 | `WGUI_PASSWORD_FILE`        | Optional filepath for the user login password. Will be hashed automatically. Used for db initialization only. Leave `WGUI_PASSWORD` blank to take effect                    | N/A                                |

custom/js/helper.js

@@ -18,6 +18,11 @@ function renderClientList(data) {
             allowedIpsHtml += `<small class="badge badge-secondary">${obj}</small>&nbsp;`;
         })
 
+        let subnetRangesString = "";
+        if (obj.Client.subnet_ranges && obj.Client.subnet_ranges.length > 0) {
+            subnetRangesString = obj.Client.subnet_ranges.join(',')
+        }
+
         // render client html content
         let html = `<div class="col-sm-6 col-md-6 col-lg-4" id="client_${obj.Client.id}">
                         <div class="info-box">
@@ -59,6 +64,7 @@ function renderClientList(data) {
                                 <hr>
                                 <span class="info-box-text"><i class="fas fa-user"></i> ${obj.Client.name}</span>
                                 <span class="info-box-text" style="display: none"><i class="fas fa-key"></i> ${obj.Client.public_key}</span>
+                                <span class="info-box-text" style="display: none"><i class="fas fa-subnetrange"></i>${subnetRangesString}</span>
                                 <span class="info-box-text"><i class="fas fa-envelope"></i> ${obj.Client.email}</span>
                                 <span class="info-box-text"><i class="fas fa-clock"></i>
                                     ${prettyDateTime(obj.Client.created_at)}</span>

handler/routes.go

@@ -366,6 +366,10 @@ func GetClients(db store.IStore) echo.HandlerFunc {
 			})
 		}
 
+		for i, clientData := range clientDataList {
+			clientDataList[i] = util.FillClientSubnetRange(clientData)
+		}
+
 		return c.JSON(http.StatusOK, clientDataList)
 	}
 }
@@ -391,7 +395,7 @@ func GetClient(db store.IStore) echo.HandlerFunc {
 			return c.JSON(http.StatusNotFound, jsonHTTPResponse{false, "Client not found"})
 		}
 
-		return c.JSON(http.StatusOK, clientData)
+		return c.JSON(http.StatusOK, util.FillClientSubnetRange(clientData))
 	}
 }
 
@@ -988,6 +992,13 @@ func MachineIPAddresses() echo.HandlerFunc {
 	}
 }
 
+// GetOrderedSubnetRanges handler to get the ordered list of subnet ranges
+func GetOrderedSubnetRanges() echo.HandlerFunc {
+	return func(c echo.Context) error {
+		return c.JSON(http.StatusOK, util.SubnetRangesOrder)
+	}
+}
+
 // SuggestIPAllocation handler to get the list of ip address for client
 func SuggestIPAllocation(db store.IStore) echo.HandlerFunc {
 	return func(c echo.Context) error {
@@ -1009,20 +1020,46 @@ func SuggestIPAllocation(db store.IStore) echo.HandlerFunc {
 				false, "Cannot suggest ip allocation: failed to get list of allocated ip addresses",
 			})
 		}
-		for _, cidr := range server.Interface.Addresses {
+
-			ip, err := util.GetAvailableIP(cidr, allocatedIPs)
+		sr := c.QueryParam("sr")
+		searchCIDRList := make([]string, 0)
+		found := false
+
+		// Use subnet range or default to interface addresses
+		if util.SubnetRanges[sr] != nil {
+			for _, cidr := range util.SubnetRanges[sr] {
+				searchCIDRList = append(searchCIDRList, cidr.String())
+			}
+		} else {
+			searchCIDRList = append(searchCIDRList, server.Interface.Addresses...)
+		}
+
+		// Save only unique IPs
+		ipSet := make(map[string]struct{})
+
+		for _, cidr := range searchCIDRList {
+			ip, err := util.GetAvailableIP(cidr, allocatedIPs, server.Interface.Addresses)
 			if err != nil {
 				log.Error("Failed to get available ip from a CIDR: ", err)
+				continue
+			}
+			found = true
+			if strings.Contains(ip, ":") {
+				ipSet[fmt.Sprintf("%s/128", ip)] = struct{}{}
+			} else {
+				ipSet[fmt.Sprintf("%s/32", ip)] = struct{}{}
+			}
+		}
+
+		if !found {
 			return c.JSON(http.StatusInternalServerError, jsonHTTPResponse{
 				false,
-					fmt.Sprintf("Cannot suggest ip allocation: failed to get available ip from network %s", cidr),
+				"Cannot suggest ip allocation: failed to get available ip. Try a different subnet or deallocate some ips.",
 			})
 		}
-			if strings.Contains(ip, ":") {
+
-				suggestedIPs = append(suggestedIPs, fmt.Sprintf("%s/128", ip))
+		for ip := range ipSet {
-			} else {
+			suggestedIPs = append(suggestedIPs, ip)
-				suggestedIPs = append(suggestedIPs, fmt.Sprintf("%s/32", ip))
-			}
 		}
 
 		return c.JSON(http.StatusOK, suggestedIPs)

main.go

@@ -45,6 +45,7 @@ var (
 	flagSessionSecret  string = util.RandomString(32)
 	flagWgConfTemplate string
 	flagBasePath       string
+	flagSubnetRanges   string
 )
 
 const (
@@ -81,6 +82,7 @@ func init() {
 	flag.StringVar(&flagEmailFromName, "email-from-name", util.LookupEnvOrString("EMAIL_FROM_NAME", flagEmailFromName), "'From' email name.")
 	flag.StringVar(&flagWgConfTemplate, "wg-conf-template", util.LookupEnvOrString("WG_CONF_TEMPLATE", flagWgConfTemplate), "Path to custom wg.conf template.")
 	flag.StringVar(&flagBasePath, "base-path", util.LookupEnvOrString("BASE_PATH", flagBasePath), "The base path of the URL")
+	flag.StringVar(&flagSubnetRanges, "subnet-ranges", util.LookupEnvOrString("SUBNET_RANGES", flagSubnetRanges), "IP ranges to choose from when assigning an IP for a client.")
 
 	var (
 		smtpPasswordLookup  = util.LookupEnvOrString("SMTP_PASSWORD", flagSmtpPassword)
@@ -127,6 +129,7 @@ func init() {
 	util.SessionSecret = []byte(flagSessionSecret)
 	util.WgConfTemplate = flagWgConfTemplate
 	util.BasePath = util.ParseBasePath(flagBasePath)
+	util.SubnetRanges = util.ParseSubnetRanges(flagSubnetRanges)
 
 	// print only if log level is INFO or lower
 	if lvl, _ := util.ParseLogLevel(util.LookupEnvOrString(util.LogLevel, "INFO")); lvl <= log.INFO {
@@ -145,6 +148,7 @@ func init() {
 		//fmt.Println("Session secret\t:", util.SessionSecret)
 		fmt.Println("Custom wg.conf\t:", util.WgConfTemplate)
 		fmt.Println("Base path\t:", util.BasePath+"/")
+		fmt.Println("Subnet ranges\t:", util.GetSubnetRangesString())
 	}
 }
 
@@ -170,6 +174,17 @@ func main() {
 	// create the wireguard config on start, if it doesn't exist
 	initServerConfig(db, tmplDir)
 
+	// Check if subnet ranges are valid for the server configuration
+	// Remove any non-valid CIDRs
+	if err := util.ValidateAndFixSubnetRanges(db); err != nil {
+		panic(err)
+	}
+
+	// Print valid ranges
+	if lvl, _ := util.ParseLogLevel(util.LookupEnvOrString(util.LogLevel, "INFO")); lvl <= log.INFO {
+		fmt.Println("Valid subnet ranges:", util.GetSubnetRangesString())
+	}
+
 	// register routes
 	app := router.New(tmplDir, extraData, util.SessionSecret)
 
@@ -218,6 +233,7 @@ func main() {
 	app.GET(util.BasePath+"/api/clients", handler.GetClients(db), handler.ValidSession)
 	app.GET(util.BasePath+"/api/client/:id", handler.GetClient(db), handler.ValidSession)
 	app.GET(util.BasePath+"/api/machine-ips", handler.MachineIPAddresses(), handler.ValidSession)
+	app.GET(util.BasePath+"/api/subnet-ranges", handler.GetOrderedSubnetRanges(), handler.ValidSession)
 	app.GET(util.BasePath+"/api/suggest-client-ips", handler.SuggestIPAllocation(db), handler.ValidSession)
 	app.POST(util.BasePath+"/api/apply-wg-config", handler.ApplyServerConfig(db, tmplDir), handler.ValidSession, handler.ContentTypeJson)
 	app.GET(util.BasePath+"/wake_on_lan_hosts", handler.GetWakeOnLanHosts(db), handler.ValidSession)

model/client.go

@@ -12,6 +12,7 @@ type Client struct {
 	PresharedKey    string    `json:"preshared_key"`
 	Name            string    `json:"name"`
 	Email           string    `json:"email"`
+	SubnetRanges    []string  `json:"subnet_ranges,omitempty"`
 	AllocatedIPs    []string  `json:"allocated_ips"`
 	AllowedIPs      []string  `json:"allowed_ips"`
 	ExtraAllowedIPs []string  `json:"extra_allowed_ips"`

templates/base.html

@@ -58,11 +58,13 @@
                 </div>
                 <div class="form-group form-group-sm">
                     <select name="status-selector" id="status-selector" class="custom-select form-control-navbar" style="margin-left: 0.5em; height: 90%; font-size: 14px;">
+                        <!-- THIS SECTION IS OVERRIDDEN BY JS. SEE updateSearchList() function in clients.html BEFORE EDITING -->
                         <option value="All">All</option>
                         <option value="Enabled">Enabled</option>
                         <option value="Disabled">Disabled</option>
                         <option value="Connected">Connected</option>
                         <option value="Disconnected">Disconnected</option>
+                        <!-- THIS SECTION IS OVERRIDDEN BY JS. SEE updateSearchList() function in clients.html BEFORE EDITING -->
                     </select>
                 </div>
             </form>
@@ -209,6 +211,12 @@
                                 <label for="client_email" class="control-label">Email</label>
                                 <input type="text" class="form-control" id="client_email" name="client_email">
                             </div>
+                            <div class="form-group">
+                                <label for="subnet_ranges" class="control-label">Subnet range</label>
+                                <select id="subnet_ranges" class="select2"
+                                    data-placeholder="Select a subnet range" style="width: 100%;">
+                                </select>
+                            </div>
                             <div class="form-group">
                                 <label for="client_allocated_ips" class="control-label">IP Allocation</label>
                                 <input type="text" data-role="tagsinput" class="form-control" id="client_allocated_ips">
@@ -368,6 +376,36 @@
 
         $(document).ready(function () {
 
+            addGlobalStyle(`
+.toast-top-right-fix {
+    top: 67px;
+    right: 12px;
+}
+            `, 'toastrToastStyleFix')
+
+            toastr.options.closeDuration = 100;
+            // toastr.options.timeOut = 10000;
+            toastr.options.positionClass = 'toast-top-right-fix';
+
+            updateApplyConfigVisibility()
+            // from clients.html
+            updateSearchList()
+
+        });
+
+        function addGlobalStyle(css, id) {
+            if (!document.querySelector('#' + id)) {
+                let head = document.head
+                if (!head) { return }
+                let style = document.createElement('style')
+                style.type = 'text/css'
+                style.id = id
+                style.innerHTML = css
+                head.appendChild(style)
+            }
+        }
+
+        function updateApplyConfigVisibility() {
                 $.ajax({
                     cache: false,
                     method: 'GET',
@@ -388,8 +426,7 @@
                         toastr.error(responseJson['message']);
                     }
                 });
-
+        }
-        });
 
         
         // populateClient function for render new client info
@@ -456,6 +493,7 @@
                     if (window.location.pathname === "{{.basePath}}/") {
                         populateClient(resp.id);
                     }
+                    updateApplyConfigVisibility()
                 },
                 error: function(jqXHR, exception) {
                     const responseJson = jQuery.parseJSON(jqXHR.responseText);
@@ -466,19 +504,32 @@
 
         // updateIPAllocationSuggestion function for automatically fill
         // the IP Allocation input with suggested ip addresses
-        function updateIPAllocationSuggestion() {
+        function updateIPAllocationSuggestion(forceDefault = false) {
+            let subnetRange = $("#subnet_ranges").select2('val');
+
+            if (forceDefault || !subnetRange || subnetRange.length === 0) {
+                subnetRange = '__default_any__'
+            }
             $.ajax({
                 cache: false,
                 method: 'GET',
-                url: '{{.basePath}}/api/suggest-client-ips',
+                url: `{{.basePath}}/api/suggest-client-ips?sr=${subnetRange}`,
                 dataType: 'json',
                 contentType: "application/json",
                 success: function(data) {
+                    const allocated_ips = $("#client_allocated_ips").val().split(",");
+                    allocated_ips.forEach(function (item, index) {
+                        $('#client_allocated_ips').removeTag(escape(item));
+                    })
                     data.forEach(function (item, index) {
                         $('#client_allocated_ips').addTag(item);
                     })
                 },
                 error: function(jqXHR, exception) {
+                    const allocated_ips = $("#client_allocated_ips").val().split(",");
+                    allocated_ips.forEach(function (item, index) {
+                        $('#client_allocated_ips').removeTag(escape(item));
+                    })
                     const responseJson = jQuery.parseJSON(jqXHR.responseText);
                     toastr.error(responseJson['message']);
                 }
@@ -497,7 +548,6 @@
             'defaultText': 'Add More',
             'removeWithBackspace': true,
             'minChars': 0,
-            'minInputWidth': '100%',
             'placeholderColor': '#666666'
         });
 
@@ -509,7 +559,6 @@
             'defaultText': 'Add More',
             'removeWithBackspace': true,
             'minChars': 0,
-            'minInputWidth': '100%',
             'placeholderColor': '#666666'
         });
 
@@ -520,7 +569,6 @@
             'defaultText': 'Add More',
             'removeWithBackspace': true,
             'minChars': 0,
-            'minInputWidth': '100%',
             'placeholderColor': '#666666'
         });
 
@@ -565,10 +613,17 @@
                 $("#client_preshared_key").val("");
                 $("#client_allocated_ips").importTags('');
                 $("#client_extra_allowed_ips").importTags('');
-                updateIPAllocationSuggestion();
+                updateSubnetRangesList("#subnet_ranges");
+                updateIPAllocationSuggestion(true);
             });
         });
 
+        // handle subnet range select
+        $('#subnet_ranges').on('select2:select', function (e) {
+            // console.log('Selected Option: ', $("#subnet_ranges").select2('val'));
+            updateIPAllocationSuggestion();
+        });
+
         // apply_config_confirm button event
         $(document).ready(function () {
             $("#apply_config_confirm").click(function () {
@@ -579,6 +634,7 @@
                     dataType: 'json',
                     contentType: "application/json",
                     success: function(data) {
+                        updateApplyConfigVisibility()
                         $("#modal_apply_config").modal('hide');
                         toastr.success('Applied config successfully');
                     },

templates/clients.html

@@ -100,6 +100,12 @@ Wireguard Clients
                         <label for="_client_email" class="control-label">Email</label>
                         <input type="text" class="form-control" id="_client_email" name="client_email">
                     </div>
+                    <div class="form-group">
+                        <label for="_subnet_ranges" class="control-label">Subnet range</label>
+                        <select id="_subnet_ranges" class="select2"
+                            data-placeholder="Select a subnet range" style="width: 100%;">
+                        </select>
+                    </div>
                     <div class="form-group">
                         <label for="_client_allocated_ips" class="control-label">IP Allocation</label>
                         <input type="text" data-role="tagsinput" class="form-control" id="_client_allocated_ips">
@@ -253,12 +259,101 @@ Wireguard Clients
             setClientStatus(clientID, true);
             const divElement = document.getElementById("paused_" + clientID);
             divElement.style.visibility = "hidden";
+            updateApplyConfigVisibility()
         }
 
         function pauseClient(clientID) {
             setClientStatus(clientID, false);
             const divElement = document.getElementById("paused_" + clientID);
             divElement.style.visibility = "visible";
+            updateApplyConfigVisibility()
+        }
+
+        // updateIPAllocationSuggestion function for automatically fill
+        // the IP Allocation input with suggested ip addresses
+        // FOR CHANGING A SUBNET OF AN EXISTING CLIENT
+        function updateIPAllocationSuggestionExisting() {
+            let subnetRange = $("#_subnet_ranges").select2('val');
+
+            if (!subnetRange || subnetRange.length === 0) {
+                subnetRange = '__default_any__'
+            }
+            $.ajax({
+                cache: false,
+                method: 'GET',
+                url: `{{.basePath}}/api/suggest-client-ips?sr=${subnetRange}`,
+                dataType: 'json',
+                contentType: "application/json",
+                success: function(data) {
+                    const allocated_ips = $("#_client_allocated_ips").val().split(",");
+                    allocated_ips.forEach(function (item, index) {
+                        $('#_client_allocated_ips').removeTag(escape(item));
+                    })
+                    data.forEach(function (item, index) {
+                        $('#_client_allocated_ips').addTag(item);
+                    })
+                },
+                error: function(jqXHR, exception) {
+                    const allocated_ips = $("#_client_allocated_ips").val().split(",");
+                    allocated_ips.forEach(function (item, index) {
+                        $('#_client_allocated_ips').removeTag(escape(item));
+                    })
+                    const responseJson = jQuery.parseJSON(jqXHR.responseText);
+                    toastr.error(responseJson['message']);
+                }
+            });
+        }
+
+        function updateSubnetRangesList(elementID, preselectedVal) {
+            $.getJSON("{{.basePath}}/api/subnet-ranges", null, function(data) {
+                $(`${elementID} option`).remove();
+                $(elementID).append(
+                    $("<option></option>")
+                        .text("Any")
+                        .val("__default_any__")
+                );
+                $.each(data, function(index, item) {
+                    $(elementID).append(
+                        $("<option></option>")
+                            .text(item)
+                            .val(item)
+                    );
+                    if (item === preselectedVal) {
+                        console.log(preselectedVal);
+                        $(elementID).val(preselectedVal).trigger('change')
+                    }
+                });
+            });
+        }
+
+        function updateSearchList() {
+            $.getJSON("{{.basePath}}/api/subnet-ranges", null, function(data) {
+                $("#status-selector option").remove();
+                $("#status-selector").append(
+                    $("<option></option>")
+                        .text("All")
+                        .val("All"),
+                    $("<option></option>")
+                        .text("Enabled")
+                        .val("Enabled"),
+                    $("<option></option>")
+                        .text("Disabled")
+                        .val("Disabled"),
+                    $("<option></option>")
+                        .text("Connected")
+                        .val("Connected"),
+                    $("<option></option>")
+                        .text("Disconnected")
+                        .val("Disconnected")
+                );
+                $.each(data, function(index, item) {
+                    $("#status-selector").append(
+                        $("<option></option>")
+                            .text(item)
+                            .val(item)
+                    );
+                });
+            });
 }
     </script>
     <script>
@@ -349,7 +444,18 @@ Wireguard Clients
                     });
                     break;
                 default:
-                    $('.col-lg-4').show();
+                    $('.col-lg-4').hide();
+                    const selectedSR = $("#status-selector").val()
+                    $(".fa-subnetrange").each(function () {
+                        const srs = $(this).parent().text().trim().split(',')
+                        for (const sr of srs) {
+                            if (sr === selectedSR) {
+                                $(this).closest('.col-lg-4').show();
+                                break
+                            }                            
+                        }
+                    })
+                    // $('.col-lg-4').show();
                     break;
             }
         });
@@ -400,6 +506,7 @@ Wireguard Clients
                         toastr.success('Removed client successfully');
                         const divElement = document.getElementById('client_' + client_id);
                         divElement.style.display = "none";
+                        updateApplyConfigVisibility()
                     },
                     error: function(jqXHR, exception) {
                         const responseJson = jQuery.parseJSON(jqXHR.responseText);
@@ -427,7 +534,6 @@ Wireguard Clients
                     'defaultText': 'Add More',
                     'removeWithBackspace': true,
                     'minChars': 0,
-                    'minInputWidth': '100%',
                     'placeholderColor': '#666666'
                 });
 
@@ -439,7 +545,6 @@ Wireguard Clients
                     'defaultText': 'Add More',
                     'removeWithBackspace': true,
                     'minChars': 0,
-                    'minInputWidth': '100%',
                     'placeholderColor': '#666666'
                 });
 
@@ -450,7 +555,6 @@ Wireguard Clients
                     'defaultText': 'Add More',
                     'removeWithBackspace' : true,
                     'minChars': 0,
-                    'minInputWidth': '100%',
                     'placeholderColor': '#666666'
                 })
 
@@ -469,6 +573,13 @@ Wireguard Clients
                         modal.find("#_client_name").val(client.name);
                         modal.find("#_client_email").val(client.email);
 
+                        let preselectedEl
+                        if (client.subnet_ranges && client.subnet_ranges.length > 0) {
+                            preselectedEl = client.subnet_ranges[0]
+                        }
+
+                        updateSubnetRangesList("#_subnet_ranges", preselectedEl);
+
                         modal.find("#_client_allocated_ips").importTags('');
                         client.allocated_ips.forEach(function (obj) {
                             modal.find("#_client_allocated_ips").addTag(obj);
@@ -491,6 +602,11 @@ Wireguard Clients
 
                         modal.find("#_client_public_key").val(client.public_key);
                         modal.find("#_client_preshared_key").val(client.preshared_key);
+
+                        // handle subnet range select
+                        $('#_subnet_ranges').on('select2:select', function (e) {
+                            updateIPAllocationSuggestionExisting();
+                        });
                     },
                     error: function (jqXHR, exception) {
                         const responseJson = jQuery.parseJSON(jqXHR.responseText);

templates/global_settings.html

@@ -203,7 +203,6 @@ Global Settings
             'defaultText': 'Add More',
             'removeWithBackspace': true,
             'minChars': 0,
-            'minInputWidth': '100%',
             'placeholderColor': '#666666'
         });
 

templates/server.html

@@ -167,7 +167,6 @@ Wireguard Server Settings
             'defaultText': 'Add More',
             'removeWithBackspace': true,
             'minChars': 0,
-            'minInputWidth': '100%',
             'placeholderColor': '#666666'
         });
 

util/cache.go

@@ -0,0 +1,3 @@
+package util
+
+var IPToSubnetRange = map[string]uint16{}

util/config.go

@@ -1,6 +1,11 @@
 package util
 
-import "strings"
+import (
+	"net"
+	"strings"
+
+	"github.com/labstack/gommon/log"
+)
 
 // Runtime config
 var (
@@ -19,6 +24,8 @@ var (
 	SessionSecret     []byte
 	WgConfTemplate    string
 	BasePath          string
+	SubnetRanges      map[string]([]*net.IPNet)
+	SubnetRangesOrder []string
 )
 
 const (
@@ -66,3 +73,45 @@ func ParseBasePath(basePath string) string {
 	}
 	return basePath
 }
+
+func ParseSubnetRanges(subnetRangesStr string) map[string]([]*net.IPNet) {
+	subnetRanges := map[string]([]*net.IPNet){}
+	if subnetRangesStr == "" {
+		return subnetRanges
+	}
+	cidrSet := map[string]bool{}
+	subnetRangesStr = strings.TrimSpace(subnetRangesStr)
+	subnetRangesStr = strings.Trim(subnetRangesStr, ";:,")
+	ranges := strings.Split(subnetRangesStr, ";")
+	for _, rng := range ranges {
+		rng = strings.TrimSpace(rng)
+		rngSpl := strings.Split(rng, ":")
+		if len(rngSpl) != 2 {
+			log.Warnf("Unable to parse subnet range: %v. Skipped.", rng)
+			continue
+		}
+		rngName := strings.TrimSpace(rngSpl[0])
+		subnetRanges[rngName] = make([]*net.IPNet, 0)
+		cidrs := strings.Split(rngSpl[1], ",")
+		for _, cidr := range cidrs {
+			cidr = strings.TrimSpace(cidr)
+			_, net, err := net.ParseCIDR(cidr)
+			if err != nil {
+				log.Warnf("[%v] Unable to parse CIDR: %v. Skipped.", rngName, cidr)
+				continue
+			}
+			if cidrSet[net.String()] {
+				log.Warnf("[%v] CIDR already exists: %v. Skipped.", rngName, net.String())
+				continue
+			}
+			cidrSet[net.String()] = true
+			subnetRanges[rngName] = append(subnetRanges[rngName], net)
+		}
+		if len(subnetRanges[rngName]) == 0 {
+			delete(subnetRanges, rngName)
+		} else {
+			SubnetRangesOrder = append(SubnetRangesOrder, rngName)
+		}
+	}
+	return subnetRanges
+}

util/util.go

@@ -95,6 +95,15 @@ func ClientDefaultsFromEnv() model.ClientDefaults {
 	return clientDefaults
 }
 
+// ContainsCIDR to check if ipnet1 contains ipnet2
+// https://stackoverflow.com/a/40406619/6111641
+// https://go.dev/play/p/Q4J-JEN3sF
+func ContainsCIDR(ipnet1, ipnet2 *net.IPNet) bool {
+	ones1, _ := ipnet1.Mask.Size()
+	ones2, _ := ipnet2.Mask.Size()
+	return ones1 <= ones2 && ipnet1.Contains(ipnet2.IP)
+}
+
 // ValidateCIDR to validate a network CIDR
 func ValidateCIDR(cidr string) bool {
 	_, _, err := net.ParseCIDR(cidr)
@@ -317,15 +326,32 @@ func GetBroadcastIP(n *net.IPNet) net.IP {
 	return broadcast
 }
 
+// GetBroadcastAndNetworkAddrsLookup get the ip address that can't be used with current server interfaces
+func GetBroadcastAndNetworkAddrsLookup(interfaceAddresses []string) map[string]bool {
+	list := make(map[string]bool, 0)
+	for _, ifa := range interfaceAddresses {
+		_, net, err := net.ParseCIDR(ifa)
+		if err != nil {
+			continue
+		}
+
+		broadcastAddr := GetBroadcastIP(net).String()
+		networkAddr := net.IP.String()
+		list[broadcastAddr] = true
+		list[networkAddr] = true
+	}
+	return list
+}
+
 // GetAvailableIP get the ip address that can be allocated from an CIDR
-func GetAvailableIP(cidr string, allocatedList []string) (string, error) {
+// We need interfaceAddresses to find real broadcast and network addresses
+func GetAvailableIP(cidr string, allocatedList, interfaceAddresses []string) (string, error) {
 	ip, net, err := net.ParseCIDR(cidr)
 	if err != nil {
 		return "", err
 	}
 
-	broadcastAddr := GetBroadcastIP(net).String()
+	unavailableIPs := GetBroadcastAndNetworkAddrsLookup(interfaceAddresses)
-	networkAddr := net.IP.String()
 
 	for ip := ip.Mask(net.Mask); net.Contains(ip); inc(ip) {
 		available := true
@@ -336,7 +362,7 @@ func GetAvailableIP(cidr string, allocatedList []string) (string, error) {
 				break
 			}
 		}
-		if available && suggestedAddr != networkAddr && suggestedAddr != broadcastAddr {
+		if available && !unavailableIPs[suggestedAddr] {
 			return suggestedAddr, nil
 		}
 	}
@@ -384,6 +410,126 @@ func ValidateIPAllocation(serverAddresses []string, ipAllocatedList []string, ip
 	return true, nil
 }
 
+// findSubnetRangeForIP to find first SR for IP, and cache the match
+func findSubnetRangeForIP(cidr string) (uint16, error) {
+	ip, _, err := net.ParseCIDR(cidr)
+	if err != nil {
+		return 0, err
+	}
+
+	if srName, ok := IPToSubnetRange[ip.String()]; ok {
+		return srName, nil
+	}
+
+	for srIndex, sr := range SubnetRangesOrder {
+		for _, srCIDR := range SubnetRanges[sr] {
+			if srCIDR.Contains(ip) {
+				IPToSubnetRange[ip.String()] = uint16(srIndex)
+				return uint16(srIndex), nil
+			}
+		}
+	}
+	return 0, fmt.Errorf("Subnet range not found for this IP")
+}
+
+// FillClientSubnetRange to fill subnet ranges client belongs to, does nothing if SRs are not found
+func FillClientSubnetRange(client model.ClientData) model.ClientData {
+	cl := *client.Client
+	for _, ip := range cl.AllocatedIPs {
+		sr, err := findSubnetRangeForIP(ip)
+		if err != nil {
+			continue
+		}
+		cl.SubnetRanges = append(cl.SubnetRanges, SubnetRangesOrder[sr])
+	}
+	return model.ClientData{
+		Client: &cl,
+		QRCode: client.QRCode,
+	}
+}
+
+// ValidateAndFixSubnetRanges to check if subnet ranges are valid for the server configuration
+// Removes all non-valid CIDRs
+func ValidateAndFixSubnetRanges(db store.IStore) error {
+	if len(SubnetRangesOrder) == 0 {
+		return nil
+	}
+
+	server, err := db.GetServer()
+	if err != nil {
+		return err
+	}
+	var serverSubnets []*net.IPNet
+	for _, addr := range server.Interface.Addresses {
+		addr = strings.TrimSpace(addr)
+		_, net, err := net.ParseCIDR(addr)
+		if err != nil {
+			return err
+		}
+		serverSubnets = append(serverSubnets, net)
+	}
+
+	for _, rng := range SubnetRangesOrder {
+		cidrs := SubnetRanges[rng]
+		if len(cidrs) > 0 {
+			newCIDRs := make([]*net.IPNet, 0)
+			for _, cidr := range cidrs {
+				valid := false
+
+				for _, serverSubnet := range serverSubnets {
+					if ContainsCIDR(serverSubnet, cidr) {
+						valid = true
+						break
+					}
+				}
+
+				if valid {
+					newCIDRs = append(newCIDRs, cidr)
+				} else {
+					log.Warnf("[%v] CIDR is outside of all server subnets: %v. Removed.", rng, cidr)
+				}
+			}
+
+			if len(newCIDRs) > 0 {
+				SubnetRanges[rng] = newCIDRs
+			} else {
+				delete(SubnetRanges, rng)
+				log.Warnf("[%v] No valid CIDRs in this subnet range. Removed.", rng)
+			}
+		}
+	}
+
+	return nil
+}
+
+// GetSubnetRangesString to get a formatted string, representing active subnet ranges
+func GetSubnetRangesString() string {
+	if len(SubnetRangesOrder) == 0 {
+		return ""
+	}
+
+	strB := strings.Builder{}
+
+	for _, rng := range SubnetRangesOrder {
+		cidrs := SubnetRanges[rng]
+		if len(cidrs) > 0 {
+			strB.WriteString(rng)
+			strB.WriteString(":[")
+			first := true
+			for _, cidr := range cidrs {
+				if !first {
+					strB.WriteString(", ")
+				}
+				strB.WriteString(cidr.String())
+				first = false
+			}
+			strB.WriteString("]  ")
+		}
+	}
+
+	return strings.TrimSpace(strB.String())
+}
+
 // WriteWireGuardServerConfig to write Wireguard server config. e.g. wg0.conf
 func WriteWireGuardServerConfig(tmplDir fs.FS, serverConfig model.Server, clientDataList []model.ClientData, usersList []model.User, globalSettings model.GlobalSetting) error {
 	var tmplWireguardConf string