test: add DHCPv4 client hostname resend regression test

Signed-off-by: Ejub Sabic <ejub1946@outlook.com>
2026-07-22 01:13:00 +02:00 · 2026-04-28 18:00:28 +02:00
parent 82ffb0f4bc
commit 17965bf4cc
7 changed files with 198 additions and 0 deletions
@@ -7,6 +7,7 @@ Tests verifying DHCPv4/DHCPv6 client and server functionality:
 - DHCPv4 client with default gateway assignment
 - DHCPv4 client with static route configuration
 - DHCPv4 client hostname management and priority
+ - DHCPv4 client hostname option is resent after system hostname changes
 - Basic DHCPv6 client operation with address assignment
 - DHCPv6 client with prefix delegation (IA_PD)
 - DHCPv6 SLAAC/RA (Stateless)
@@ -30,6 +31,10 @@ include::client_hostname/Readme.adoc[]

 <<<

+include::client_hostname_resend/Readme.adoc[]
+
+<<<
+
 include::client6_basic/Readme.adoc[]

 <<<
@@ -0,0 +1 @@
+test.adoc
@@ -0,0 +1,30 @@
+=== DHCP Hostname Resend
+
+ifdef::topdoc[:imagesdir: {topdoc}../../test/case/dhcp/client_hostname_resend]
+
+==== Description
+
+Verify that updating the system hostname regenerates the DHCP client
+Finit service file so subsequent DHCP requests advertise the current
+hostname (option 12, RFC 2132).
+
+Regression test for a bug where the DHCP client callback only reacts
+on diffs in infix-dhcp-client, so a standalone change of
+ietf-system:system/hostname leaves the previously written
+/etc/finit.d/available/dhcp-client-<iface>.conf untouched and the
+running udhcpc keeps announcing the old name.
+
+==== Topology
+
+image::topology.svg[DHCP Hostname Resend topology, align=center, scaledwidth=75%]
+
+==== Sequence
+
+. Set up topology and attach to target DUT
+. Configure initial hostname '{HOSTNM_A}'
+. Enable DHCP client sending hostname option
+. Verify Finit service carries hostname '{HOSTNM_A}'
+. Update system hostname to '{HOSTNM_B}'
+. Verify Finit service is regenerated with '{HOSTNM_B}'
+
+
@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+"""DHCP Hostname Resend
+
+Verify that updating the system hostname regenerates the DHCP client
+Finit service file so subsequent DHCP requests advertise the current
+hostname (option 12, RFC 2132).
+
+Regression test for a bug where the DHCP client callback only reacts
+on diffs in infix-dhcp-client, so a standalone change of
+ietf-system:system/hostname leaves the previously written
+/etc/finit.d/available/dhcp-client-<iface>.conf untouched and the
+running udhcpc keeps announcing the old name.
+
+"""
+
+import infamy
+from infamy.util import until
+
+
+def finit_conf(ssh, ifname):
+    """Return the contents of the generated DHCP client Finit service file."""
+    path = f"/etc/finit.d/available/dhcp-client-{ifname}.conf"
+    cmd = ssh.runsh(f"cat {path} 2>/dev/null")
+    return cmd.stdout
+
+
+def udhcpc_cmdline(ssh, ifname):
+    """Return the NUL-separated argv of the running udhcpc for ifname."""
+    pidfile = f"/run/dhcp-client-{ifname}.pid"
+    cmd = ssh.runsh(
+        f"p=$(cat {pidfile} 2>/dev/null); "
+        f"[ -n \"$p\" ] && tr '\\0' ' ' < /proc/$p/cmdline"
+    )
+    return cmd.stdout
+
+
+def running_hostname(ssh, ifname):
+    """Extract the hostname udhcpc is currently announcing (-x hostname:<name>)."""
+    for tok in udhcpc_cmdline(ssh, ifname).split():
+        if tok.startswith("hostname:"):
+            return tok.split(":", 1)[1]
+    return None
+
+
+with infamy.Test() as test:
+    HOSTNM_A = "infix-resend-a"
+    HOSTNM_B = "infix-resend-b"
+
+    with test.step("Set up topology and attach to target DUT"):
+        env = infamy.Env()
+        client = env.attach("client", "mgmt")
+        clissh = env.attach("client", "mgmt", "ssh")
+        _, port = env.ltop.xlate("client", "mgmt")
+
+    with test.step(f"Configure initial hostname '{HOSTNM_A}'"):
+        client.put_config_dict("ietf-system", {
+            "system": {
+                "hostname": HOSTNM_A
+            }
+        })
+        until(lambda: client.get_data("/ietf-system:system")
+              .get("system", {}).get("hostname") == HOSTNM_A)
+
+    with test.step("Enable DHCP client sending hostname option"):
+        client.put_config_dict("ietf-interfaces", {
+            "interfaces": {
+                "interface": [{
+                    "name": port,
+                    "ipv4": {
+                        "infix-dhcp-client:dhcp": {
+                            "option": [
+                                {"id": "vendor-class", "value": "infamy"},
+                                {"id": "hostname", "value": "auto"},
+                                {"id": "netmask"},
+                                {"id": "router"}
+                            ]
+                        }
+                    }
+                }]
+            }
+        })
+
+    with test.step(f"Verify running udhcpc announces hostname '{HOSTNM_A}'"):
+        until(lambda: running_hostname(clissh, port) == HOSTNM_A)
+
+    with test.step(f"Update system hostname to '{HOSTNM_B}'"):
+        client.put_config_dict("ietf-system", {
+            "system": {
+                "hostname": HOSTNM_B
+            }
+        })
+        until(lambda: client.get_data("/ietf-system:system")
+              .get("system", {}).get("hostname") == HOSTNM_B)
+
+    with test.step(f"Verify running udhcpc announces hostname '{HOSTNM_B}'"):
+        try:
+            until(lambda: running_hostname(clissh, port) == HOSTNM_B,
+                  attempts=15)
+        except Exception:
+            cur = running_hostname(clissh, port)
+            print(f"udhcpc still announcing hostname '{cur}', expected '{HOSTNM_B}'")
+            test.fail()
+
+    test.succeed()
@@ -0,0 +1,22 @@
+graph "1x1" {
+	layout="neato";
+	overlap="false";
+	esep="+100";
+
+        node [shape=record, fontname="DejaVu Sans Mono, Book"];
+	edge [color="cornflowerblue", penwidth="2", fontname="DejaVu Serif, Book"];
+
+	host [
+	    label="host | { <mgmt> mgmt }",
+	    pos="0,20!",
+	    requires="controller",
+	];
+
+        client [
+	    label="{ <mgmt> mgmt } | client",
+	    pos="200,20!",
+	    requires="infix",
+	];
+
+	host:mgmt -- client:mgmt [requires="mgmt", color=lightgrey]
+}
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
+ "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+
+<!-- Title: 1x1 Pages: 1 -->
+<svg width="474pt" height="45pt"
+ viewBox="0.00 0.00 474.04 45.00" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+<g id="graph0" class="graph" transform="scale(1 1) rotate(0) translate(4 41)">
+<title>1x1</title>
+<polygon fill="white" stroke="transparent" points="-4,4 -4,-41 470.04,-41 470.04,4 -4,4"/>
+<!-- host -->
+<g id="node1" class="node">
+<title>host</title>
+<polygon fill="none" stroke="black" points="0,-0.5 0,-36.5 100,-36.5 100,-0.5 0,-0.5"/>
+<text text-anchor="middle" x="25" y="-14.8" font-family="DejaVu Sans Mono, Book" font-size="14.00">host</text>
+<polyline fill="none" stroke="black" points="50,-0.5 50,-36.5 "/>
+<text text-anchor="middle" x="75" y="-14.8" font-family="DejaVu Sans Mono, Book" font-size="14.00">mgmt</text>
+</g>
+<!-- client -->
+<g id="node2" class="node">
+<title>client</title>
+<polygon fill="none" stroke="black" points="350.04,-0.5 350.04,-36.5 466.04,-36.5 466.04,-0.5 350.04,-0.5"/>
+<text text-anchor="middle" x="375.04" y="-14.8" font-family="DejaVu Sans Mono, Book" font-size="14.00">mgmt</text>
+<polyline fill="none" stroke="black" points="400.04,-0.5 400.04,-36.5 "/>
+<text text-anchor="middle" x="433.04" y="-14.8" font-family="DejaVu Sans Mono, Book" font-size="14.00">client</text>
+</g>
+<!-- host&#45;&#45;client -->
+<g id="edge1" class="edge">
+<title>host:mgmt&#45;&#45;client:mgmt</title>
+<path fill="none" stroke="lightgrey" stroke-width="2" d="M100,-18.5C100,-18.5 350.04,-18.5 350.04,-18.5"/>
+</g>
+</g>
+</svg>
@@ -14,6 +14,9 @@
 - name: DHCP Hostname Priority
  case: client_hostname/test.py

+- name: DHCP Hostname Resend
+  case: client_hostname_resend/test.py
+
 - name: DHCPv6 Basic
  case: client6_basic/test.py