From e062a8c11856f213983f5b41f50d4f9dbc0dde0f Mon Sep 17 00:00:00 2001
From: Christian Breunig <christian@breunig.cc>
Date: Tue, 3 Oct 2023 18:14:23 +0200
Subject: pppoe: T5630: allow to specify MRU in addition to already
 configurable MTU

Set the MRU (Maximum Receive Unit) value to n. PPPd will ask the peer to send
packets of no more than n bytes. The value of n must be between 128 and 16384,
the default was always 1492 to match PPPoE MTU.

A value of 296 works well on very slow links (40 bytes for TCP/IP header + 256
bytes of data). Note that for the IPv6 protocol, the MRU must be at least 1280.

CLI:
  set interfaces pppoe pppoe0 mru 1280
---
 data/templates/pppoe/peer.j2                   |  2 +-
 interface-definitions/interfaces-pppoe.xml.in  | 14 ++++++++++++++
 smoketest/scripts/cli/test_interfaces_pppoe.py |  4 ++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/data/templates/pppoe/peer.j2 b/data/templates/pppoe/peer.j2
index f30cefe63..2a99fcb2a 100644
--- a/data/templates/pppoe/peer.j2
+++ b/data/templates/pppoe/peer.j2
@@ -50,7 +50,7 @@ ifname {{ ifname }}
 ipparam {{ ifname }}
 debug
 mtu {{ mtu }}
-mru {{ mtu }}
+mru {{ mru }}
 
 {% if authentication is vyos_defined %}
 {{ 'user "' + authentication.username + '"' if authentication.username is vyos_defined }}
diff --git a/interface-definitions/interfaces-pppoe.xml.in b/interface-definitions/interfaces-pppoe.xml.in
index b78f92c85..30fcb8573 100644
--- a/interface-definitions/interfaces-pppoe.xml.in
+++ b/interface-definitions/interfaces-pppoe.xml.in
@@ -109,6 +109,20 @@
           <leafNode name="mtu">
             <defaultValue>1492</defaultValue>
           </leafNode>
+          <leafNode name="mru">
+            <properties>
+              <help>Maximum Receive Unit (MRU)</help>
+              <valueHelp>
+                <format>u32:128-16384</format>
+                <description>Maximum Receive Unit in byte</description>
+              </valueHelp>
+              <constraint>
+                <validator name="numeric" argument="--range 128-16384"/>
+              </constraint>
+              <constraintErrorMessage>MRU must be between 128 and 16384</constraintErrorMessage>
+            </properties>
+            <defaultValue>1492</defaultValue>
+          </leafNode>
           #include <include/interface/no-peer-dns.xml.i>
           <leafNode name="remote-address">
             <properties>
diff --git a/smoketest/scripts/cli/test_interfaces_pppoe.py b/smoketest/scripts/cli/test_interfaces_pppoe.py
index 0ce5e2fe0..0685833fb 100755
--- a/smoketest/scripts/cli/test_interfaces_pppoe.py
+++ b/smoketest/scripts/cli/test_interfaces_pppoe.py
@@ -59,10 +59,12 @@ class PPPoEInterfaceTest(VyOSUnitTestSHIM.TestCase):
             user = f'VyOS-user-{interface}'
             passwd = f'VyOS-passwd-{interface}'
             mtu = '1400'
+            mru = '1300'
 
             self.cli_set(base_path + [interface, 'authentication', 'username', user])
             self.cli_set(base_path + [interface, 'authentication', 'password', passwd])
             self.cli_set(base_path + [interface, 'mtu', mtu])
+            self.cli_set(base_path + [interface, 'mru', mru])
             self.cli_set(base_path + [interface, 'no-peer-dns'])
 
             # check validate() - a source-interface is required
@@ -80,6 +82,8 @@ class PPPoEInterfaceTest(VyOSUnitTestSHIM.TestCase):
 
             tmp = get_config_value(interface, 'mtu')[1]
             self.assertEqual(tmp, mtu)
+            tmp = get_config_value(interface, 'mru')[1]
+            self.assertEqual(tmp, mru)
             tmp = get_config_value(interface, 'user')[1].replace('"', '')
             self.assertEqual(tmp, user)
             tmp = get_config_value(interface, 'password')[1].replace('"', '')
-- 
cgit v1.2.3


From e357258e645cf85de0035d4ecfbf99db4dd90f7e Mon Sep 17 00:00:00 2001
From: Christian Breunig <christian@breunig.cc>
Date: Tue, 3 Oct 2023 20:51:21 +0200
Subject: pppoe: T5630: verify MRU is less or equal then MTU

---
 smoketest/scripts/cli/test_interfaces_pppoe.py | 7 ++++++-
 src/conf_mode/interfaces-pppoe.py              | 5 +++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/smoketest/scripts/cli/test_interfaces_pppoe.py b/smoketest/scripts/cli/test_interfaces_pppoe.py
index 0685833fb..7b702759f 100755
--- a/smoketest/scripts/cli/test_interfaces_pppoe.py
+++ b/smoketest/scripts/cli/test_interfaces_pppoe.py
@@ -64,7 +64,7 @@ class PPPoEInterfaceTest(VyOSUnitTestSHIM.TestCase):
             self.cli_set(base_path + [interface, 'authentication', 'username', user])
             self.cli_set(base_path + [interface, 'authentication', 'password', passwd])
             self.cli_set(base_path + [interface, 'mtu', mtu])
-            self.cli_set(base_path + [interface, 'mru', mru])
+            self.cli_set(base_path + [interface, 'mru', '9000'])
             self.cli_set(base_path + [interface, 'no-peer-dns'])
 
             # check validate() - a source-interface is required
@@ -72,6 +72,11 @@ class PPPoEInterfaceTest(VyOSUnitTestSHIM.TestCase):
                 self.cli_commit()
             self.cli_set(base_path + [interface, 'source-interface', self._source_interface])
 
+            # check validate() - MRU needs to be less or equal then MTU
+            with self.assertRaises(ConfigSessionError):
+                self.cli_commit()
+            self.cli_set(base_path + [interface, 'mru', mru])
+
         # commit changes
         self.cli_commit()
 
diff --git a/src/conf_mode/interfaces-pppoe.py b/src/conf_mode/interfaces-pppoe.py
index fca91253c..0a03a172c 100755
--- a/src/conf_mode/interfaces-pppoe.py
+++ b/src/conf_mode/interfaces-pppoe.py
@@ -77,6 +77,11 @@ def verify(pppoe):
     if {'connect_on_demand', 'vrf'} <= set(pppoe):
         raise ConfigError('On-demand dialing and VRF can not be used at the same time')
 
+    # both MTU and MRU have default values, thus we do not need to check
+    # if the key exists
+    if int(pppoe['mru']) > int(pppoe['mtu']):
+        raise ConfigError('PPPoE MRU needs to be lower then MTU!')
+
     return None
 
 def generate(pppoe):
-- 
cgit v1.2.3