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Expand LAN to 10.0.0.0/22 with static/reserved/dynamic/spare zones

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Splits the LAN into four /24 zones: 10.0.0.0/24 static (no DHCP, DNS
only), 10.0.1.0/24 fixed DHCP reservations by MAC, 10.0.2.0/24 dynamic
DHCP pool, 10.0.3.0/24 spare/unused. ipadm now derives the required
subnet from whether a host has a MAC, auto-assigns free IPs, and
auto-migrates a host's IP when its MAC is added/removed. Migrated the
existing archerc80 reservation from 10.0.0.2 to 10.0.1.2.

Also fixes a latent bug found while doing this: dnsmasq's SIGHUP
(`systemctl reload`) only re-reads /etc/hosts, not the conf-dir files
ipadm writes to, so config changes were silently not applied on
reload. ipadm now restarts dnsmasq instead.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
mike
2026-08-21 08:57:58 +02:00
co-authored by Claude Sonnet 5
parent 78beedeabc
commit c135f205fa
10 changed files with 364 additions and 112 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tools/ipadm/main.go
+66 -25
View File
@@ -14,7 +14,7 @@ import (
"text/tabwriter"
)
const version = "1.1.0"
const version = "1.2.0"
type usageRow struct {
left string
@@ -25,7 +25,7 @@ type usageRow struct {
var usageRows = []usageRow{
{"ipadm <hostname>", "add/edit host (interactive)", false},
{"ipadm -l", "list hosts", false},
{"ipadm -a [-f] <hostname> <ip address> [mac address]", "add host", false},
{"ipadm -a [-f] <hostname> [ip address] [mac address]", "add host (IP auto-assigned if omitted)", false},
{"ipadm -c <hostname> <comment>", "set comment", false},
{"ipadm -i <hostname> <ip address>", "change ip address", false},
{"ipadm -m <hostname> <mac address>", "change mac address", false},
@@ -34,7 +34,7 @@ var usageRows = []usageRow{
{"ipadm -pa [-f] <hostname> <wan-port> [lan-port] [tcp|udp|both]", "add port-forward to a known host", true},
{"ipadm -pl", "list port-forwards", false},
{"ipadm -pd <wan-port> [tcp|udp|both]", "delete port-forward", false},
{"ipadm -u", "update (regenerate dnsmasq+nftables config, reload)", false},
{"ipadm -u", "update (regenerate dnsmasq+nftables config, apply)", false},
{"ipadm -h", "this help", false},
}
@@ -73,11 +73,25 @@ var usage = buildUsage()
// netConfig describes the LAN/WAN the tool validates against. Overridable
// via env vars, mainly so this can be tested without touching the real
// /etc files.
//
// The LAN is a /22 split into four /24s: staticCIDR for hosts without a MAC
// (manually configured on the device, DNS only), reservedCIDR for hosts with
// a MAC (DHCP static reservation), plus a dynamic DHCP pool and a reserved,
// currently unused /24 that ipadm doesn't need to know about.
type netConfig struct {
lanCIDR string
poolStart string
poolEnd string
wanIface string
staticCIDR string
reservedCIDR string
gatewayIP string
wanIface string
}
// cidrFor returns the subnet a host with the given MAC (possibly empty)
// belongs in.
func (c netConfig) cidrFor(mac string) string {
if mac == "" {
return c.staticCIDR
}
return c.reservedCIDR
}
func envOr(key, def string) string {
@@ -105,10 +119,10 @@ func nftPortFwdPath() string {
func loadNetConfig() netConfig {
return netConfig{
lanCIDR: envOr("IPADM_LAN_CIDR", "10.0.0.0/24"),
poolStart: envOr("IPADM_POOL_START", "10.0.0.100"),
poolEnd: envOr("IPADM_POOL_END", "10.0.0.200"),
wanIface: envOr("IPADM_WAN_IFACE", "enp3s0"),
staticCIDR: envOr("IPADM_STATIC_CIDR", "10.0.0.0/24"),
reservedCIDR: envOr("IPADM_RESERVED_CIDR", "10.0.1.0/24"),
gatewayIP: envOr("IPADM_GATEWAY_IP", "10.0.0.1"),
wanIface: envOr("IPADM_WAN_IFACE", "enp3s0"),
}
}
@@ -276,13 +290,13 @@ func cmdAdd(args []string) {
force = true
args = args[1:]
}
if len(args) < 2 || len(args) > 3 {
fail("usage: ipadm -a [-f] <hostname> <ip address> [mac address]")
if len(args) < 1 || len(args) > 3 {
fail("usage: ipadm -a [-f] <hostname> [ip address] [mac address]")
}
name, ip := args[0], args[1]
mac := ""
if len(args) == 3 {
mac = args[2]
name := args[0]
ip, mac, err := classifyHostArgs(args[1:])
if err != nil {
fail("%s", err)
}
cfg := loadNetConfig()
@@ -290,9 +304,6 @@ func cmdAdd(args []string) {
if err := validateHostname(name); err != nil {
return nil, "", err
}
if err := validateIP(ip, cfg.lanCIDR, cfg.poolStart, cfg.poolEnd); err != nil {
return nil, "", err
}
normMac, err := normalizeMAC(mac)
if err != nil {
return nil, "", err
@@ -302,6 +313,18 @@ func cmdAdd(args []string) {
if idx >= 0 && !force {
return nil, "", fmt.Errorf("host %q already exists (use -f to overwrite, or `ipadm %s` to edit it)", name, name)
}
cidr := cfg.cidrFor(normMac)
if ip == "" {
freeIP, err := nextFreeIP(hosts, cidr, idx, cfg.gatewayIP)
if err != nil {
return nil, "", err
}
ip = freeIP
} else if err := validateIP(ip, cidr, cfg.gatewayIP); err != nil {
return nil, "", err
}
if other := findByIP(hosts, ip, idx); other >= 0 {
return nil, "", fmt.Errorf("IP %s is already assigned to host %q", ip, hosts[other].Name)
}
@@ -312,10 +335,10 @@ func cmdAdd(args []string) {
h := Host{Name: name, IP: ip, MAC: normMac}
if idx >= 0 {
hosts[idx] = h
return hosts, fmt.Sprintf("Host %q overwritten (-f).", name), nil
return hosts, fmt.Sprintf("Host %q overwritten (-f), IP %s.", name, ip), nil
}
hosts = append(hosts, h)
return hosts, fmt.Sprintf("Host %q added.", name), nil
return hosts, fmt.Sprintf("Host %q added with IP %s.", name, ip), nil
})
}
@@ -346,7 +369,8 @@ func cmdChangeIP(args []string) {
if idx < 0 {
return nil, "", fmt.Errorf("host %q not found", name)
}
if err := validateIP(ip, cfg.lanCIDR, cfg.poolStart, cfg.poolEnd); err != nil {
cidr := cfg.cidrFor(hosts[idx].MAC)
if err := validateIP(ip, cidr, cfg.gatewayIP); err != nil {
return nil, "", err
}
if other := findByIP(hosts, ip, idx); other >= 0 {
@@ -365,6 +389,7 @@ func cmdChangeMAC(args []string) {
if mac == "-" {
mac = ""
}
cfg := loadNetConfig()
withStore(func(hosts []Host) ([]Host, string, error) {
idx := findHost(hosts, name)
if idx < 0 {
@@ -377,12 +402,28 @@ func cmdChangeMAC(args []string) {
if other := findByMAC(hosts, normMac, idx); other >= 0 {
return nil, "", fmt.Errorf("MAC %s is already assigned to host %q", normMac, hosts[other].Name)
}
hosts[idx].MAC = normMac
label := normMac
if label == "" {
label = "(removed)"
}
return hosts, fmt.Sprintf("MAC of %q changed to %s.", name, label), nil
summary := fmt.Sprintf("MAC of %q changed to %s.", name, label)
// The subnet a host belongs in depends on whether it has a MAC
// (see netConfig). If that changed, move it to a free IP in the
// now-correct subnet instead of leaving it in the wrong one.
targetCIDR := cfg.cidrFor(normMac)
if validateIP(hosts[idx].IP, targetCIDR, cfg.gatewayIP) != nil {
newIP, err := nextFreeIP(hosts, targetCIDR, idx, cfg.gatewayIP)
if err != nil {
return nil, "", fmt.Errorf("MAC changed, but host must move to %s and no free IP is left there: %w", targetCIDR, err)
}
oldIP := hosts[idx].IP
hosts[idx].IP = newIP
summary += fmt.Sprintf(" Host moved from %s to %s (subnet %s).", oldIP, newIP, targetCIDR)
}
return hosts, summary, nil
})
}
@@ -566,7 +607,7 @@ func cmdUpdate() {
if err := applyDnsmasqConfig(dnsmasqHostsPath(), dnsContent); err != nil {
fail("%s", err)
}
fmt.Printf("%s updated, dnsmasq reloaded (%d hosts).\n", dnsmasqHostsPath(), len(hosts))
fmt.Printf("%s updated, dnsmasq restarted (%d hosts).\n", dnsmasqHostsPath(), len(hosts))
fs, err := openPortFwdStore(portFwdDBPath())
if err != nil {