First draft of advanced DHCP option specification on Ports tab. (#1073)

* First draft of advanced DHCP option specification on Ports tab.

Allows the node administrator to specify additional DHCP options that
will be supplied to LAN clients in specific circumstances. This change
adds two tables to the Ports configuration tab.

The "Tags for Advanced DHCP Options" table allows the administrator to
specify DHCP tags that will be assigned to clients that identify
themselves with specific values for properties such as Vendor Class or
MAC address.

The "Advanced DHCP Options" table allows the administrator to specify
arbitrary DHCP options to send to any client, or only to clients with a
specific tag. Option numbers can be entered directly or chosen from a
list of well-known options. Option values are manually entered by the
administrator.

In-browser validation is implemented for all input fields with easily
recognizable content such as host names, MAC addresses, and port and
option numbers. Placeholders are also supplied for input fields, such as
MAC addresses with wildcard matching, that might otherwise be difficult
to describe.

Issues with the current version:
- Sending DHCP options not requested by the client is implemented using
the dhcp_option_force UCI configuration option, but does not currently
work.
- Tagging by client host name is supported by dnsmasq, but not yet by
UCI.
- DHCP option values must be entered manually by the administrator, but
are not currently validated.

* Better validation, placeholders, and hints for existing input fields.

* Remove junk accidentally inserted in comment.

* Preserve Advanced DHCP options across updates.

files/etc/arednsysupgrade.conf

@@ -3,6 +3,10 @@
 /etc/config.mesh/_setup
 /etc/config.mesh/_setup.dhcp.dmz
 /etc/config.mesh/_setup.dhcp.nat
+/etc/config.mesh/_setup.dhcptags.dmz
+/etc/config.mesh/_setup.dhcptags.nat
+/etc/config.mesh/_setup.dhcpoptions.dmz
+/etc/config.mesh/_setup.dhcpoptions.nat
 /etc/config.mesh/_setup.ports.dmz
 /etc/config.mesh/_setup.ports.nat
 /etc/config.mesh/_setup.services.dmz

files/usr/local/bin/node-setup

@@ -252,16 +252,22 @@ end
 -- select ports and dhcp files based on mode
 local portfile  = "/etc/config.mesh/_setup.ports"
 local dhcpfile  = "/etc/config.mesh/_setup.dhcp"
+local dhcptagsfile = "/etc/config.mesh/_setup.dhcptags"
+local dhcpoptionsfile = "/etc/config.mesh/_setup.dhcpoptions"
 local aliasfile = "/etc/config.mesh/aliases"
 local servfile = "/etc/config.mesh/_setup.services"
 if is_null(cfg.dmz_mode) then
     portfile = portfile .. ".nat"
     dhcpfile = dhcpfile .. ".nat"
+    dhcptagsfile = dhcptagsfile .. ".nat"
+    dhcpoptionsfile = dhcpoptionsfile .. ".nat"
     aliasfile = aliasfile .. ".nat"
     servfile = servfile .. ".nat"
 else
     portfile = portfile .. ".dmz"
     dhcpfile = dhcpfile .. ".dmz"
+    dhcptagsfile = dhcptagsfile .. ".dmz"
+    dhcpoptionsfile = dhcpoptionsfile .. ".dmz"
     aliasfile = aliasfile .. ".dmz"
     servfile = servfile .. ".dmz"
 end
@@ -632,21 +638,89 @@ if add_masq then
 end
 
 -- setup node lan dhcp
-if nc:get("aredn", "@wan[0]", "lan_dhcp_route") == "1" or nc:get("aredn", "@wan[0]", "lan_dhcp_defaultroute") == "1" then
+function load_dhcp_tags(dhcptagsfile)
-    -- Provide stateless routes and default route
+    local dhcp_tags = {}
-    nc:set("dhcp", "@dhcp[0]", "dhcp_option", {
+
-        "121,10.0.0.0/8," .. cfg.lan_ip .. ",0.0.0.0/0," .. cfg.lan_ip,
+    for line in io.lines(dhcptagsfile)
-        "249,10.0.0.0/8," .. cfg.lan_ip .. ",0.0.0.0/0," .. cfg.lan_ip
+    do
-    })
+        if not (line:match("^%s*#") or line:match("^%s*$")) then
-else
+            local name, condition, pattern = line:match("(%S+)%s+(%S+)%s+(.*)")
-    -- Provide stateless routes to the mesh, and a blank default route (option 3 has no values) to
+            if pattern then
-    -- surpress default route being sent
+                local cond_table = dhcp_tags[condition]
-    nc:set("dhcp", "@dhcp[0]", "dhcp_option", {
+                if not cond_table then
-        "121,10.0.0.0/8," .. cfg.lan_ip,
+                    cond_table = {}
-        "249,10.0.0.0/8," .. cfg.lan_ip,
+                    dhcp_tags[condition] = cond_table
-        "3"
+                end
-    })
+                table.insert(cond_table, {name = name, pattern = pattern})
+            end
+        end
+    end
+    return dhcp_tags
 end
+
+function load_dhcp_options(dhcpoptionsfile)
+    local dhcp_options = {}
+    for line in io.lines(dhcpoptionsfile)
+    do
+        if not (line:match("^%s*#") or line:match("^%s*$")) then
+            local tag, force, opt_num, opt_val = line:match("(%S*)%s+(%w+)%s+(%d+)%s+(.*)")
+            if opt_val then
+                table.insert(dhcp_options, {
+                            tag = tag,
+                            force = force == "force",
+                            num = opt_num,
+                            val = opt_val})
+            end
+        end
+    end
+    return dhcp_options
+end
+
+if nixio.fs.access(dhcptagsfile) then
+    for condition, cond_table in pairs(load_dhcp_tags(dhcptagsfile))
+    do
+        for i, props in ipairs(cond_table)
+        do
+            nc:add("dhcp", condition)
+            nc:set("dhcp", string.format("@%s[%d]", condition, i-1), "networkid", props.name)
+            nc:set("dhcp", string.format("@%s[%d]", condition, i-1), condition, props.pattern)
+        end
+    end
+end
+do
+    local dhcp_option_list = {}
+    if nc:get("aredn", "@wan[0]", "lan_dhcp_route") == "1" or nc:get("aredn", "@wan[0]", "lan_dhcp_defaultroute") == "1" then
+        -- Provide stateless routes and default route
+        table.insert(dhcp_option_list, "121,10.0.0.0/8," .. cfg.lan_ip .. ",0.0.0.0/0," .. cfg.lan_ip)
+        table.insert(dhcp_option_list, "249,10.0.0.0/8," .. cfg.lan_ip .. ",0.0.0.0/0," .. cfg.lan_ip)
+    else
+        -- Provide stateless routes to the mesh, and a blank default route (option 3 has no values) to
+        -- suppress default route being sent
+        table.insert(dhcp_option_list, "121,10.0.0.0/8," .. cfg.lan_ip)
+        table.insert(dhcp_option_list, "249,10.0.0.0/8," .. cfg.lan_ip)
+        table.insert(dhcp_option_list, "3")
+    end
+    if nixio.fs.access(dhcpoptionsfile) then
+        local forced_advanced_options = {}
+        for _, option in ipairs(load_dhcp_options(dhcpoptionsfile))
+        do
+            local parts = {}
+            if option.tag ~= "" then
+                table.insert(parts, "tag:" .. option.tag)
+            end
+            table.insert(parts, option.num)
+            table.insert(parts, option.val)
+            table.insert(option.force and forced_advanced_options or dhcp_option_list, table.concat(parts, ","))
+        end
+        if #forced_advanced_options > 0 then
+            nc:set("dhcp", "@dhcp[0]", "dhcp_option_force", forced_advanced_options)
+        end
+    end
+    if #dhcp_option_list > 0 then
+        nc:set("dhcp", "@dhcp[0]", "dhcp_option", dhcp_option_list)
+    end
+end
+
 nc:commit("dhcp")
 
 -- generate the wireless config file

files/www/cgi-bin/ports

@@ -97,6 +97,67 @@ function validate_service_suffix(suffix)
     end
 end
 
+local mac_pattern = "%x%x:%x%x:%x%x:%x%x:%x%x:%x%x"
+local mac_wildcard = "*:*:*:*:*:*"
+
+-- accepts nonempty strings
+local function validate_nonempty_matcher(matcher)
+    return matcher ~= ""
+end
+
+-- accepts MAC addresses with optional bytewise wildcard substitution
+local function validate_mac_matcher(matcher)
+    return matcher:gsub("%x%x", "*") == mac_wildcard
+end
+
+-- accepts host names with optional trailing wildcard
+local function validate_host_matcher(matcher)
+    return matcher:match("^%w[%w.-]*%*?$")
+end
+
+local dhcp_tag_conds = {
+    { key = "vendorclass",
+      name = "Vendor Class",
+      validator = validate_nonempty_matcher,
+      hint = "all or part of the class value sent by the client",
+      jsPlaceholder = "subpart of class string",
+    },
+    { key = "userclass",
+      name = "User Class",
+      validator = validate_nonempty_matcher,
+      hint = "all or part of the class value sent by the client",
+      jsPlaceholder = "subpart of class string",
+    },
+    { key = "mac",
+      name = "MAC Address",
+      validator = validate_mac_matcher,
+      hint = "six bytes, each either two hexadecimal digits or a single asterisk, separated by colons",
+      jsPattern = [[^(?:(?:[0-9a-fA-F]{2}|\\*):){5}(?:[0-9a-fA-F]{2}|\\*)$]],
+      jsPlaceholder = "*:*:*:*:*:*",
+    },
+    { key = "name",
+      name = "Host Name",
+      validator = validate_host_matcher,
+      hint = "alphanumerics, hyphens, and dots, with an optional trailing asterisk",
+      jsPattern = [[^[a-zA-Z0-9][a-zA-Z0-9.\\-]*\\*?$]],
+      jsPlaceholder = "client.host-name*",
+    },
+}
+
+local dhcp_tag_validators = {}
+for _, cond in ipairs(dhcp_tag_conds)
+do
+    dhcp_tag_validators[cond.key] = {
+        validator = cond.validator,
+        hint = cond.hint,
+        jsPattern = cond.jsPattern,
+        jsPlaceholder = cond.jsPlaceholder}
+end
+
+function html_safe(s)
+    return s:gsub("&", "&amp;"):gsub(">", "&gt;"):gsub("<", "&lt;")
+end
+
 local serv_err = {}
 function serverr(msg)
     serv_err[#serv_err + 1] = msg:gsub(">", "&gt;"):gsub("<", "&lt;")
@@ -114,6 +175,14 @@ local dhcp_err = {}
 function dhcperr(msg)
     dhcp_err[#dhcp_err + 1] = msg
 end
+local dhcptag_err = {}
+function dhcptagerr(msg)
+    dhcptag_err[#dhcptag_err + 1] = msg
+end
+local dhcpopt_err = {}
+function dhcpopterr(msg)
+    dhcpopt_err[#dhcpopt_err + 1] = msg
+end
 local alias_err = {}
 function aliaserr(msg)
     alias_err[#alias_err + 1] = msg
@@ -169,6 +238,8 @@ nixio.fs.mkdir(tmpdir)
 local fsuffix = dmz_mode == 0 and ".nat" or ".dmz"
 local portfile = "/etc/config.mesh/_setup.ports" .. fsuffix
 local dhcpfile = "/etc/config.mesh/_setup.dhcp" .. fsuffix
+local dhcptagsfile = "/etc/config.mesh/_setup.dhcptags" .. fsuffix
+local dhcpoptionsfile = "/etc/config.mesh/_setup.dhcpoptions" .. fsuffix
 local servfile = "/etc/config.mesh/_setup.services" .. fsuffix
 local aliasfile = "/etc/config.mesh/aliases" .. fsuffix
 
@@ -226,6 +297,45 @@ if parms.button_reset or not parms.reload then
     end
     parms.dhcp_num = i
 
+    -- set dhcp tags
+    i = 0
+    if nixio.fs.stat(dhcptagsfile) then
+        for line in io.lines(dhcptagsfile)
+        do
+            if not (line:match("^%s*#") or line:match("^%s*$")) then
+                local name, condition, pattern = line:match("(%S+)%s+(%S+)%s+(.*)")
+                if pattern then
+                    i = i + 1
+                    local prefix = "dhcptag" .. i .. "_"
+                    parms[prefix .. "name"] = name
+                    parms[prefix .. "cond"] = condition
+                    parms[prefix .. "pat"] = pattern
+                end
+            end
+        end
+    end
+    parms.dhcptags_num = i
+
+    -- set dhcp options
+    i = 0
+    if nixio.fs.stat(dhcpoptionsfile) then
+        for line in io.lines(dhcpoptionsfile)
+        do
+            if not (line:match("^%s*#") or line:match("^%s*$")) then
+                local tag, force, opt_num, opt_val = line:match("(%S*)%s+(%w+)%s+(%d+)%s+(.*)")
+                if force then
+                    i = i + 1
+                    local prefix = "dhcpopt" .. i .. "_"
+                    parms[prefix .. "tag"] = tag
+                    parms[prefix .. "force"] = force
+                    parms[prefix .. "num"] = opt_num
+                    parms[prefix .. "val"] = opt_val
+                end
+            end
+        end
+    end
+    parms.dhcpoptions_num = i
+
     -- services
     i = 0
     if nixio.fs.stat(servfile) then
@@ -270,7 +380,7 @@ if parms.button_reset or not parms.reload then
     end
     parms.alias_num = i
 
-    -- sanatize the 'add' values
+    -- sanitize the 'add' values
     parms.port_add_intf = dmz_mode ~= 0 and "wan" or "wifi"
     parms.port_add_type = "tcp"
     if not parms.dmz_ip then
@@ -283,6 +393,12 @@ if parms.button_reset or not parms.reload then
     parms.dhcp_add_ip = ""
     parms.dhcp_add_mac = ""
     parms.dhcp_add_noprop = ""
+    parms.dhcptag_add_name = ""
+    parms.dhcptag_add_cond = ""
+    parms.dhcptag_add_pat = ""
+    parms.dhcpopt_add_tag = ""
+    parms.dhcpopt_add_num = ""
+    parms.dhcpopt_add_val = ""
     parms.serv_add_name = ""
     parms.serv_add_proto = ""
     parms.serv_add_host = ""
@@ -298,12 +414,17 @@ local dhcp_end = dhcp_start + dhcp_limit - 1
 
 -- load and validate the ports
 
-local list = {}
+function make_addable_list(max_row)
-for i = 1,parms.port_num
+    local list = {}
-do
+    for i = 1,max_row
-    list[#list + 1] = i
+    do
+        list[#list + 1] = i
+    end
+    list[#list + 1] = "_add"
+    return list
 end
-list[#list + 1] = "_add"
+
+local list = make_addable_list(parms.port_num)
 local port_num = 0
 local usedports = {}
 
@@ -415,12 +536,7 @@ parms.port_num = port_num
 
 -- load and validate the dhcp reservations
 
-local list = {}
+local list = make_addable_list(parms.dhcp_num)
-for i = 1,parms.dhcp_num
-do
-    list[#list + 1] = i
-end
-list[#list + 1] = "_add"
 local dhcp_num = 0
 
 for _, val in ipairs(list)
@@ -501,7 +617,7 @@ do
             end
         end
 
-        if mac:match("[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]") then
+        if mac:match(mac_pattern) then
             if macs[mac] then
                 dhcperr(val .. " MAC " .. mac .. " is already in use")
             end
@@ -613,13 +729,162 @@ if f then
     f:close()
 end
 
--- aliases
+function write_temp_records(filename, group_name, record_count, fields)
-local list = {}
+    local f = io.open(tmpdir .. "/" .. filename, "w")
-for i = 1,parms.alias_num
+    if f then
-do
+        for i = 1,record_count
-    list[#list + 1] = i
+        do
+            local prefix = group_name .. i .. "_"
+            local record = {}
+            for _, field in ipairs(fields)
+            do
+                table.insert(record, parms[prefix .. field])
+            end
+            f:write(table.concat(record, " ") .. "\n")
+        end
+        f:close()
+    end
 end
-list[#list + 1] = "_add"
+
+-- DHCP tags
+local list = make_addable_list(parms.dhcptags_num)
+local dhcptags_num = 0
+
+for _, val in ipairs(list)
+do
+    for _ = 1,1
+    do
+        local prefix = "dhcptag" .. val .. "_"
+        local name = parms[prefix .. "name"]
+        local cond_key = parms[prefix .. "cond"]
+        local matcher = parms[prefix .. "pat"]
+
+        if val == "_add" then
+            if not ((name ~= "" or cond_key ~= "" or matcher ~= "") and (parms.dhcptag_add or parms.button_save)) then
+                break
+            end
+        elseif parms[prefix .. "del"] then
+            break
+        end
+        if val == "_add" and parms.button_save then
+            dhcptagerr(val .. " this tag must be added or cleared out before saving changes")
+            break
+        end
+        if name and not name:match("^%w+$") then
+            dhcptagerr(val .. [[ <font color='red'>Warning!</font> The tag name "]] .. html_safe(name)
+                        .. [[" is invalid; tag names must contain only letters and digits.]])
+            break
+        end
+        if cond_key == "" then
+            dhcptagerr(val .. [[ <font color='red'>Warning!</font> Please choose a client parameter to match.]])
+            break
+        end
+        if matcher == "" then
+            dhcptagerr(val .. [[ <font color='red'>Warning!</font> Please supply a value to match to the client parameter.]])
+            break
+        else
+            local tag_validator = dhcp_tag_validators[cond_key]
+            if not tag_validator then
+                dhcptagerr(string.format([[%s <font color='red'>Warning!</font> "%s" is not a known DHCP parameter.]], val, cond_key))
+                break
+            end
+            if not tag_validator.validator(matcher) then
+                dhcptagerr(string.format([[%s <font color='red'>Warning!</font> "%s" is not a valid match for %s; must be %s]],
+                                          val, html_safe(matcher), cond_key, tag_validator.hint))
+                break
+            end
+        end
+
+        if val == "_add" and #dhcptag_err > 0 and dhcptag_err[#dhcptag_err]:match("^" .. val .. " ") then
+            break
+        end
+
+        dhcptags_num = dhcptags_num + 1
+        prefix = "dhcptag" .. dhcptags_num .. "_"
+        parms[prefix .. "name"] = name
+        parms[prefix .. "cond"] = cond_key
+        parms[prefix .. "pat"] = matcher
+        if val == "_add" then
+            parms.dhcptag_add_name = ""
+            parms.dhcptag_add_cond = ""
+            parms.dhcptag_add_pat = ""
+        end
+    end
+end
+
+-- write to temp file
+write_temp_records("dhcptags", "dhcptag", dhcptags_num, {"name", "cond", "pat"})
+parms.dhcptags_num = dhcptags_num
+
+-- DHCP options
+local list = make_addable_list(parms.dhcpoptions_num)
+local dhcpoptions_num = 0
+
+for _, val in ipairs(list)
+do
+    for _ = 1,1
+    do
+        local prefix = "dhcpopt" .. val .. "_"
+        local tag = parms[prefix .. "tag"]
+        local force = parms[prefix .. "force"]
+        if force ~= "force" then
+            force = "onrequest"
+        end
+        local opt_num = parms[prefix .. "num"]
+        local opt_val = parms[prefix .. "val"]
+
+        if val == "_add" then
+            if not ((tag ~= "" or opt_num ~= "" or opt_val ~= "") and (parms.dhcpopt_add or parms.button_save)) then
+                break
+            end
+        elseif parms[prefix .. "del"] then
+            break
+        end
+        if val == "_add" and parms.button_save then
+            dhcpopterr(val .. " this option must be added or cleared out before saving changes")
+            break
+        end
+        if tag ~= "" and not tag:match("^%w+$") then
+            dhcpopterr(val .. [[ <font color='red'>Warning!</font> The tag name "]] .. html_safe(tag) .. [[" is invalid; tag names must contain only letters and digits.]])
+            break
+        end
+        local nnum = tonumber(opt_num)
+        if not nnum or nnum < 1 or nnum > 254 then
+            dhcpopterr(val .. [[ <font color='red'>Warning!</font> Option number must be an integer in the range [1..254].]])
+            break
+        end
+        -- TODO check opt_val for suitability for opt_num
+        if opt_val == "" then
+            dhcpopterr(val .. [[ <font color='red'>Warning!</font> Please supply a value to send for this option.]])
+            break
+        end
+
+        if val == "_add" and #dhcpopt_err > 0 and dhcpopt_err[#dhcpopt_err]:match("^" .. val .. " ") then
+        --if val == "_add" and #dhcpopt_err > 0 then
+            break
+        end
+
+        dhcpoptions_num = dhcpoptions_num + 1
+        prefix = "dhcpopt" .. dhcpoptions_num .. "_"
+        parms[prefix .. "tag"] = tag
+        parms[prefix .. "force"] = force
+        parms[prefix .. "num"] = opt_num
+        parms[prefix .. "val"] = opt_val
+        if val == "_add" then
+            parms.dhcpopt_add_tag = ""
+            parms.dhcpopt_add_force = ""
+            parms.dhcpopt_add_num = ""
+            parms.dhcpopt_add_val = ""
+        end
+    end
+end
+
+-- write to temp file
+write_temp_records("dhcpoptions", "dhcpopt", dhcpoptions_num, {"tag", "force", "num", "val"})
+parms.dhcpoptions_num = dhcpoptions_num
+
+-- aliases
+local list = make_addable_list(parms.alias_num)
 local alias_num = 0
 
 for _, val in ipairs(list)
@@ -677,23 +942,11 @@ do
 end
 
 -- write to temp file
-local f = io.open(tmpdir .. "/aliases", "w")
+write_temp_records("aliases", "alias", alias_num, {"ip", "host"})
-if f then
-    for i = 1,alias_num
-    do
-        f:write(parms["alias" .. i .. "_ip"] .. " " .. parms["alias" .. i .. "_host"] .. "\n")
-    end
-    f:close()
-end
 parms.alias_num = alias_num
 
 -- load and validate services
-local list = {}
+local list = make_addable_list(parms.serv_num)
-for i = 1,parms.serv_num
-do
-    list[#list + 1] = i
-end
-list[#list + 1] = "_add"
 local serv_num = 0
 hosts[""] = true
 hosts[node] = true
@@ -806,9 +1059,11 @@ end
 parms.serv_num = serv_num
 
 -- save configuration
-if parms.button_save and not (#port_err > 0 or #dhcp_err > 0 or #dmz_err > 0 or #serv_err > 0 or #alias_err > 0) then
+if parms.button_save and not (#port_err > 0 or #dhcp_err > 0 or #dhcptag_err > 0 or #dhcpopt_err > 0 or #dmz_err > 0 or #serv_err > 0 or #alias_err > 0) then
     filecopy(tmpdir .. "/ports", portfile)
     filecopy(tmpdir .. "/dhcp", dhcpfile)
+    filecopy(tmpdir .. "/dhcptags", dhcptagsfile)
+    filecopy(tmpdir .. "/dhcpoptions", dhcpoptionsfile)
     filecopy(tmpdir .. "/services", servfile)
     filecopy(tmpdir .. "/aliases", aliasfile)
 
@@ -824,7 +1079,70 @@ end
 -- generate the page
 
 http_header()
-html.header(node .. " setup", true)
+html.header(node .. " setup", false)
+
+do
+    local function generateValidatorCaseJS(cond)
+        local caseTab = {'        case "',
+                         cond.key,
+                         '":\n          newPlaceholder = "',
+                         cond.jsPlaceholder,
+                         '";\n          newTitle = "',
+                         cond.hint}
+        if cond.jsPattern then
+            table.insert(caseTab, '";\n          newPattern = "')
+            table.insert(caseTab, cond.jsPattern)
+        end
+        table.insert(caseTab, '";\n          break;\n')
+        return table.concat(caseTab, '')
+    end
+
+    -- Note: toggleField comes from https://jsfiddle.net/6nq7w/4/
+    local scriptTab = {[[
+    <script>
+    function toggleField(hideObj,showObj){
+      hideObj.disabled=true;        
+      hideObj.style.display='none';
+      showObj.disabled=false;   
+      showObj.style.display='inline';
+      showObj.focus();
+    }
+    function setOrRemoveAttribute(elem, attrName, value) {
+      console.log(`setOrRemoveAttribute(${elem.name},${attrName},${value})`)
+      if (value == null)
+        elem.removeAttribute(attrName);
+      else
+        elem.setAttribute(attrName, value)
+    }
+    function setMatcherValidator(inputId, matcherType) {
+      console.log(`setMatcherValidator(${inputId},${matcherType})`)
+      const matcherElem = document.getElementById(inputId);
+      newPattern = null;
+      newPlaceholder = null;
+      newTitle = null;
+      switch (matcherType) {
+]]}
+    for _, cond in ipairs(dhcp_tag_conds)
+    do
+        table.insert(scriptTab, generateValidatorCaseJS(cond))
+    end
+    table.insert(scriptTab, [[
+        default:
+          break;
+      }
+      setOrRemoveAttribute(matcherElem, "placeholder", newPlaceholder);
+      setOrRemoveAttribute(matcherElem, "pattern", newPattern);
+      setOrRemoveAttribute(matcherElem, "title", newTitle);
+    }
+    </script>
+    <style>
+    input:invalid {
+      border: 2px dashed red;
+    }
+    </style>]])
+    html.print(table.concat(scriptTab, ''))
+end
+html.print("</head>")
 html.print("<body><center>")
 html.alert_banner()
 html.print("<form method=post action=/cgi-bin/ports enctype='multipart/form-data'>")
@@ -839,12 +1157,12 @@ html.print([[<tr><td align=center>
 <input type=submit name=button_reset value='Reset Values' title='Revert to the last saved settings'>&nbsp;
 <input type=button name=button_refresh value='Refresh' title='Refresh this page' onclick='window.location.reload();'>&nbsp;
 <tr><td>&nbsp;</td></tr>]])
-hide("<input type=hidden name=reload value=1></td></tr>")
+hide("<input type=hidden name=reload value=1>")
 
 -- messages
 
 if parms.button_save then
-    if #port_err > 0 or #dhcp_err > 0 or #dmz_err > 0 or #serv_err > 0 then
+    if #port_err > 0 or #dhcp_err > 0 or #dhcptag_err > 0 or #dhcpopt_err > 0 or #dmz_err > 0 or #serv_err > 0 then
         html.print("<tr><td align=center><b>Configuration NOT saved!</b></td></tr>")
     elseif #errors > 0 then
         html.print("<tr><td align=center><b>Configuration saved, however:<br>")
@@ -861,9 +1179,35 @@ end
 
 -- everything else
 
+local js_mac_pattern = [[ pattern='^(?:[0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}$' ]]
+local js_host_pattern = [[ pattern='^[a-zA-Z0-9][a-zA-Z0-9\-]*$' ]]
+local js_port_range_pattern = [[ pattern='^\s*\d{1,5}(?:\s*-\s*\d{1,5})?\s*$' ]]
+
+function print_heading_vsep()
+    html.print("<tr><td colspan=4 height=5></td></tr>")
+end
+
+function print_new_entry_vsep(val, list, columns)
+    if val == "_add" and #list > 1 then
+        html.print("<tr><td colspan=" .. columns .. " height=10></td></tr>")
+    end
+end
+
+-- mark input fields of already-added entries as "required"
+function require_existing(val)
+    return val == "_add" and "" or " required "
+end
+
+function print_errors(error_list)
+    for _, e in ipairs(error_list)
+    do
+        html.print("<tr><th colspan=8>" .. e .. "</th></tr>")
+    end
+end
+
 function print_reservations()
     html.print("<table cellpadding=0 cellspacing=0><tr><th colspan=4>DHCP Address Reservations</th></tr>")
-    html.print("<tr><td colspan=4 height=5></td></tr>")
+    print_heading_vsep()
     html.print("<tr><td align=center>Hostname</td><td align=center>IP Address</td><td align=center>MAC Address</td>")
 
     if dmz_mode ~= 0 then
@@ -871,14 +1215,9 @@ function print_reservations()
     else
         html.print("<td></td><td></td></tr>")
     end
-    html.print("<tr><td colspan=4 height=5></td></tr>")
+    print_heading_vsep()
 
-    local list = {}
+    local list = make_addable_list(parms.dhcp_num)
-    for i = 1,parms.dhcp_num
-    do
-        list[#list + 1] = i
-    end
-    list[#list + 1] = "_add"
 
     local mac_list = {}
     for _, val in ipairs(list)
@@ -889,13 +1228,11 @@ function print_reservations()
         local noprop = parms["dhcp" .. val .. "_noprop"]
         mac_list[mac] = true
 
-        if val == "_add" and #list > 1 then
+        print_new_entry_vsep(val, list, 5)
-            html.print("<tr><td colspan=4 height=10></td></tr>")
+        html.print("<tr><td><input style='width=180;' type=text placeholder='host-name' title='alphanumerics and embedded hyphens' name=dhcp" .. val .. "_host value='" .. host .. "'" .. js_host_pattern .. require_existing(val) .. "></td>")
-        end
-        html.print("<tr><td><input style='width=180;' type=text name=dhcp" .. val .. "_host value='" .. host .. "'></td>")
         html.print("<td align=center style='padding:0 4px'><select style='width:130px' name=dhcp" .. val .. "_ip>")
         if val == "_add" then
-	        html.print("<option value=''>- IP Address -</option>\n")
+            html.print("<option value=''>- IP Address -</option>\n")
         end
         for i = dhcp_start,dhcp_end
         do
@@ -909,13 +1246,10 @@ function print_reservations()
             end
         end
         html.print("</select></td>")
-        html.print("<td><input style='width:120;' type=text name=dhcp" .. val .. "_mac value='" .. mac .. "'></td>")
+        html.print("<td><input style='width:120;' type=text placeholder='aa:aa:aa:aa:aa:aa' name=dhcp" .. val .. "_mac value='" .. mac .. "'" .. js_mac_pattern .. require_existing(val) .. "></td>")
         if dmz_mode ~= 0 then
-            if noprop == "#NOPROP" then
+            html.print("<td align=center><input type=checkbox id=dhcp" .. val .. "_noprop name=dhcp" .. val .. "_noprop value='#NOPROP'"
-                html.print("<td align=center><input type=checkbox id=dhcp" .. val .. "_noprop name=dhcp" .. val .. "_noprop value='#NOPROP' checked></td>")
+                       .. (noprop == "#NOPROP" and " checked" or "") .. "></td>")
-            else
-                html.print("<td align=center><input type=checkbox id=dhcp" .. val .. "_noprop name=dhcp" .. val .. "_noprop value='#NOPROP'></td>")
-            end
         else
             html.print("<td></td>")
         end
@@ -973,12 +1307,7 @@ function print_forwarding()
     html.print("<td align=center>LAN Port</td><td>&nbsp;</td></tr>")
     html.print("<tr><td colspan=6 height=5></td></tr>")
 
-    local list = {}
+    local list = make_addable_list(parms.port_num)
-    for i = 1,parms.port_num
-    do
-        list[#list + 1] = i
-    end
-    list[#list + 1] = "_add"
     local vars = { "_intf", "_type", "_out", "_ip", "_in", "_enable", "_adv", "_link", "_proto", "_suffix", "_name" }
     for _, val in ipairs(list)
     do
@@ -987,9 +1316,7 @@ function print_forwarding()
             _G[var] = parms["port" .. val .. var]
         end
 
-        if val == "_add" and #list > 1 then
+        print_new_entry_vsep(val, list, 6)
-            html.print("<tr><td colspan=6 height=10></td></tr>")
-        end
 
         html.print("<tr>")
         hide("<input style='width:90;' type=hidden name=port" .. val .. "_enable value=1>")
@@ -1011,7 +1338,8 @@ function print_forwarding()
         html.print("<option " .. (_type == "both" and "selected" or "") .. " value='both'>Both</option>")
         html.print("</select></td>")
 
-        html.print("<td align=center valign=top><input style='width:90;' type=text name=port" .. val .. "_out value='" .. _out .. "'></td>")
+        html.print("<td align=center valign=top><input style='width:90;' type=text placeholder='9998-9999' title='integer 1-65535 or two integers separated by a hyphen' name=port" .. val .. "_out value='"
+                   .. _out .. "'" .. js_port_range_pattern .. require_existing(val) .. "></td>")
         html.print("<td align=center valign=top><select name=port" .. val .. "_ip>")
         if val == "_add" then
             html.print("<option value=''>- IP Address -</option>")
@@ -1028,7 +1356,8 @@ function print_forwarding()
         end
         html.print("</select></td>")
 
-        html.print("<td align=left valign=top><input style='width:90;' type=text name=port" .. val .. "_in value='" .. _in .. "'></td>")
+        html.print("<td align=left valign=top><input style='width:90;' type='number' min='1' max='65535' placeholder='9998' title='integer 1-65535' name=port"
+                   .. val .. "_in value='" .. _in .. "'" .. require_existing(val) .. "></td>")
         html.print("<td><nobr>&nbsp;<input type=submit name=")
 
         if val == "_add" then
@@ -1070,10 +1399,7 @@ function print_forwarding()
         end
         html.print("</select></td>")
 
-        for _, e in ipairs(dmz_err)
+        print_errors(dmz_err)
-        do
-            html.print("<tr><th colspan=8>" .. e .. "</th></tr>")
-        end
     end
     html.print("</table>")
 end
@@ -1110,12 +1436,7 @@ function print_services()
         html.print("<tr><td>Name</td><td>Link</td><td>URL</td><td><br><br></td></tr>")
     end
 
-    local list = {}
+    local list = make_addable_list(parms.serv_num)
-    for i = 1,parms.serv_num
-    do
-        list[#list + 1] = i
-    end
-    list[#list + 1] = "_add"
 
     local vars = { "_name", "_link", "_proto", "_host", "_port", "_suffix" }
     for _, val in ipairs(list)
@@ -1129,11 +1450,9 @@ function print_services()
             parms["serv" .. val .. "_host"] = node
         end
 
-        if val == "_add" and #list > 1 then
+        print_new_entry_vsep(val, list, 4)
-            html.print("<tr><td colspan=4 height=10></td></tr>")
-        end
         html.print("<tr>")
-        html.print("<td><input type=text style='width:120;' name=serv" .. val .. "_name value='" .. _name .. "' title='what to call this service'></td>")
+        html.print("<td><input type=text style='width:120;' placeholder='Service Name' name=serv" .. val .. "_name value='" .. _name .. "' title='what to call this service'></td>")
 
         html.print("<td><nobr><input type=checkbox name=serv" .. val .. "_link value=1")
         if val ~= "_add" then
@@ -1168,14 +1487,14 @@ function print_services()
             end
             html.print("</select>")
         else
-	        html.print("<td><nobr><b>:</b>//<small>" .. _host .. "</small>")
+	        html.print("<td style='width:99%'><nobr><b>:</b>//<small>" .. _host .. "</small>")
         end
 
         html.print("<b>:</b><input type=text style='width:40;' name=serv" .. val .. "_port value='" .. _port .. "' title='port number'")
         if val ~= "_add" and _link ~= "1" then
             html.print(" disabled")
         end
-        html.print("> / <input type=text style='width:80;' name=serv" .. val .. "_suffix value='" .. _suffix .. "' ")
+        html.print("> / <input type=text name=serv" .. val .. "_suffix value='" .. _suffix .. "' ")
         html.print("title='leave blank unless the URL needs a more specific path'")
         if val ~= "_add" and _link ~= "1" then
             html.print(" disabled")
@@ -1219,21 +1538,14 @@ function print_aliases()
     html.print("<tr><td align=center>Alias Name</td><td></td><td align=center>IP Address</td></tr>")
     html.print("<tr><td colspan=3 height=5></td></tr>")
 
-    local list = {}
+    local list = make_addable_list(parms.alias_num)
-    for i = 1,parms.alias_num
-    do
-        list[#list + 1] = i
-    end
-    list[#list + 1] = "_add"
 
     for _, val in ipairs(list)
     do
         local host = parms["alias" .. val .. "_host"]
         local ip = parms["alias" .. val .. "_ip"]
-        if val == "_add" and #list > 1 then
+        print_new_entry_vsep(val, list , 4)
-            html.print("<tr><td colspan=3 height=10></td></tr>\n")
+        html.print("<tr><td align=center><input type=text placeholder='alias-name' title='alphanumerics and embedded hyphens' name=alias" .. val .. "_host value='" .. host .. "' size=20" .. js_host_pattern .. require_existing(val) .. "></td>")
-        end
-        html.print("<tr><td align=center><input type=text name=alias" .. val .. "_host value='" .. host .. "' size=20></td>")
         html.print("<td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>")
         html.print("<td align=center><select name=alias" .. val .. "_ip>")
         if val == "_add" then
@@ -1266,6 +1578,197 @@ function print_aliases()
     html.print("</table>")
 end
 
+function print_dhcp_cond_selector(row, selected_key, allow_unset, patname)
+    local field_name = "dhcptag" .. row .. "_cond"
+    html.print("<td align=center style='padding:0 4px'><select name='" .. field_name
+                .. "' title='Type of identifying information sent by the client' "
+                .. "onchange='setMatcherValidator(\"" .. patname .. "\",this.value);'>")
+
+    if allow_unset then
+        html.print("<option value=''>-Parameter-</option>")
+    end
+    for _, condition in ipairs(dhcp_tag_conds)
+    do
+        html.print("<option " .. (condition.key == selected_key and "selected " or "")
+                  .. "value=\"" .. condition.key .. "\">" .. condition.name .. "</option>")
+    end
+    html.print("</select></td>")
+end
+
+function dhcp_tag_used(tag_name)
+    if tag_name == "" then
+        return false
+    end
+    for i = 1,parms.dhcpoptions_num
+    do
+        if tag_name == parms["dhcpopt" .. i .. "_tag"] then
+            return true
+        end
+    end
+    return false
+end
+
+function print_dhcp_tags()
+    html.print("<table cellpadding=0 cellspacing=0><tr><th colspan=4>Tags for Advanced DHCP Options</th></tr>")
+    print_heading_vsep()
+    html.print("<tr><td align=center>Set a Tag Named</td><td align=center>When Client's</td><td align=center style='width:99%'>Matches</td>")
+
+    local list = make_addable_list(parms.dhcptags_num)
+
+    for _, val in ipairs(list)
+    do
+        local prefix = "dhcptag" .. val .. "_"
+        local name = parms[prefix .. "name"]
+        local cond_key = parms[prefix .. "cond"]
+        local matcher = parms[prefix .. "pat"]
+
+        print_new_entry_vsep(val, list, 4)
+        html.print("<tr><td><input style='width:110px' type='text' placeholder='tagname' name='" .. prefix .. "name' value='" .. name
+                   .. "' pattern='^[a-zA-Z0-9]+$' title='Alphanumeric string identifying the tag to assign'"
+                   .. require_existing(val) .. "></td>")
+        local patname = prefix .. "pat"
+        print_dhcp_cond_selector(val, cond_key, val == "_add", patname)
+        local t = {"<td><input style='width:99%' name='",
+                   patname,
+                   "' value='",
+                   matcher,
+                   "' id='",
+                   patname,}
+        if val ~= "_add" then
+            local cond = dhcp_tag_validators[cond_key]
+            table.insert(t, "' required title='")
+            table.insert(t, cond.hint)
+            table.insert(t, "' placeholder='")
+            table.insert(t, cond.jsPlaceholder)
+            if cond.jsPattern ~= nil then
+                table.insert(t, "' pattern='")
+                table.insert(t, (cond.jsPattern:gsub("\\\\", "\\")))
+            end
+        end
+        table.insert(t, "'></td>")
+        html.print(table.concat(t, ''))
+        html.print("<td><nobr>&nbsp;<input type=submit name=")
+        if val == "_add" then
+            html.print("dhcptag_add value=Add title='Add DHCP Tag'")
+        else
+            html.print(prefix .. "del value='Del ' title=")
+            if dhcp_tag_used(name) then
+                html.print("'Cannot remove; tag is in use by an option.' disabled='disabled'")
+            else
+                html.print("'Remove DHCP Tag'")
+            end
+        end
+        html.print("></nobr></td></tr>")
+    end
+
+    print_errors(dhcptag_err)
+
+    html.print("</table>")
+end
+
+function print_dhcp_tag_selector(row, tag_name)
+    local field_name = "dhcpopt" .. row .. "_tag"
+    html.print("<td><select name='" .. field_name .. "' title='Only send this option to clients with this tag'>")
+
+    html.print("<option value=''>[any]</option>")
+    for val = 1,parms.dhcptags_num
+    do
+        local name = parms["dhcptag" .. val .. "_name"] or ""
+        local sel = ""
+        if name ~= "" and name == tag_name then
+            sel = "selected "
+        end
+        html.print("<option " .. sel .. "value=\"" .. name .. "\">" .. name .. "</option>")
+    end
+    html.print("</select></td>")
+end
+
+function print_dhcp_option_selector(known_options, row, opt_num)
+    local field_name = "dhcpopt" .. row .. "_num"
+    -- custom-value option adapted from https://jsfiddle.net/6nq7w/4/
+    html.print("<td align=center style='padding:0 4px'><select name=\"" .. field_name .. '"')
+    html.print([[ onchange="if(this.options[this.selectedIndex].value=='[numeric]'){
+              toggleField(this,this.nextSibling);
+              this.selectedIndex='0';
+          }">
+          <option value="">- DHCP Option Number -</option>
+          <option value="[numeric]">[other option number]</option>]])
+    local found = false
+    for _, option in ipairs(known_options)
+    do
+        local sel = ""
+        local nnum = tonumber(opt_num)
+        if option.num == nnum then
+            found = true
+            sel = "selected "
+        elseif nnum and not found and nnum < option.num then -- not a known option
+            found = true
+            html.print("<option selected value=" .. nnum .. ">" .. nnum .. "</option>")
+        end
+        html.print("<option " .. sel .. "value=" .. option.num .. ">" .. option.num .. " (" .. option.name .. ")</option>")
+    end
+    -- do not insert any whitespace between the following two HTML tags
+    html.print("</select><input name=\"" .. field_name .. '"')
+    html.print([[ type="number" min=1 max=254 style="display:none;" disabled="disabled" 
+            onblur="if(this.value==''){toggleField(this,this.previousSibling);}"></td>]])
+end
+
+-- load all known DHCP option names
+function load_known_options()
+    local known_options = {}
+
+    local optlist = io.popen("/usr/sbin/dnsmasq --help dhcp")
+    if optlist then
+        for line in optlist:lines()
+        do
+            local num, name = line:match("%s*(%d+)%s+(%S+)")
+            if name then
+                table.insert(known_options, {num = tonumber(num), name = name})
+            end
+        end
+        optlist:close()
+    end
+    return known_options
+end
+
+function print_dhcp_options()
+    html.print("<table cellpadding=0 cellspacing=0><tr><th colspan=5>Advanced DHCP Options</th></tr>")
+    print_heading_vsep()
+    html.print("<tr><td align=center>For Tag</td><td align=center>Always</td><td align=center>Send DHCP Option</td><td align=center style='width:99%'>With Value</td></tr>")
+
+    local known_options = load_known_options()
+
+    local list = make_addable_list(parms.dhcpoptions_num)
+    for _, val in ipairs(list)
+    do
+        local prefix = "dhcpopt" .. val .. "_"
+        local tag = parms[prefix .. "tag"] or ""
+        local force = parms[prefix .. "force"]
+        local opt_num = tonumber(parms[prefix .. "num"])
+        local opt_val = parms[prefix .. "val"] or ""
+
+        print_new_entry_vsep(val, list, 5)
+        html.print("<tr>")
+        print_dhcp_tag_selector(val, tag)
+        html.print("<td align=center><input type='checkbox' name='" .. prefix .. "force' value='force' "
+                   .. (force == "force" and "checked " or "")
+                   .. "title='Send option even when not requested by client'/></td>")
+        print_dhcp_option_selector(known_options, val, opt_num)
+        html.print("<td><input type='text' style='width:99%' name='" .. prefix .. "val' value='" .. opt_val .. "'></td>")
+        html.print("<td><nobr>&nbsp;<input type=submit name=")
+        if val == "_add" then
+            html.print("dhcpopt_add value=Add title='Add DHCP Option'")
+        else
+            html.print(prefix .. "del value='Del ' title='Remove DHCP Option'")
+        end
+        html.print("></nobr></td></tr>")
+    end
+
+    print_errors(dhcpopt_err)
+
+    html.print("</table>")
+end
+
 html.print("<tr><td align=center>")
 html.print("<table width=100%><tr><td align=center valign=top>")
 if dmz_mode ~= 0 then
@@ -1280,7 +1783,13 @@ print_services()
 html.print("</td>")
 html.print("</tr>")
 html.print("<tr><td colspan=3><hr></td></tr>")
-html.print("<tr><td align=center valign=top>")
+html.print("<tr><td valign=top>")
+print_dhcp_tags()
+html.print("</td><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign=top>")
+print_dhcp_options()
+html.print("</td></tr>")
+html.print("<tr><td colspan=3><hr></td></tr>")
+html.print("<tr><td>")
 if dmz_mode ~= 0 then
     print_forwarding()
 else
@@ -1291,10 +1800,14 @@ html.print("<td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>")
 html.print("<td align=center valign=top>")
 print_aliases()
 html.print("</td></tr>")
-html.print("</table>")
+html.print("</table></td></tr>")
-
+html.print("<tr><td>")
+html.footer()
+html.print(" </td></tr></table>")
 hide("<input type=hidden name=port_num value=" .. parms.port_num .. ">")
 hide("<input type=hidden name=dhcp_num value=" .. parms.dhcp_num .. ">")
+hide("<input type=hidden name=dhcptags_num value=" .. parms.dhcptags_num .. ">")
+hide("<input type=hidden name=dhcpoptions_num value=" .. parms.dhcpoptions_num .. ">")
 hide("<input type=hidden name=serv_num value=" .. parms.serv_num .. ">")
 hide("<input type=hidden name=alias_num value=" .. parms.alias_num .. ">")
 
@@ -1302,10 +1815,5 @@ for _, h in ipairs(hidden)
 do
     html.print(h)
 end
-
+html.print("</form></center></body></html>")
-html.print("<tr><td>")
-html.footer()
-html.print(" </td></tr>")
-html.print("</form></center></table>")
-html.print("</body></html>")
 http_footer()