From 6e1333d1e71651e9822ef74d989b928df313ea6e Mon Sep 17 00:00:00 2001
From: Daniil Baturin <daniil@baturin.org>
Date: Tue, 8 Aug 2023 20:28:38 +0100
Subject: system-ip: T5449: add TCP MSS probing options

---
 src/conf_mode/system-ip.py | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'src')

diff --git a/src/conf_mode/system-ip.py b/src/conf_mode/system-ip.py
index cca996e4f..c89267afc 100755
--- a/src/conf_mode/system-ip.py
+++ b/src/conf_mode/system-ip.py
@@ -98,6 +98,27 @@ def apply(opt):
     value = '1' if (tmp != None) else '0'
     sysctl_write('net.ipv4.fib_multipath_hash_policy', value)
 
+    # configure TCP options (defaults as of Linux 6.4)
+    tmp = dict_search('tcp.mss.probing', opt)
+    if tmp is None:
+        value = 0
+    elif tmp == 'on-icmp-black-hole':
+        value = 1
+    elif tmp == 'force':
+        value = 2
+    else:
+        # Shouldn't happen
+        raise ValueError("TCP MSS probing is neither 'on-icmp-black-hole' nor 'force'!")
+    sysctl_write('net.ipv4.tcp_mtu_probing', value)
+
+    tmp = dict_search('tcp.mss.base', opt)
+    value = '1024' if (tmp is None) else tmp
+    sysctl_write('net.ipv4.tcp_base_mss', value)
+
+    tmp = dict_search('tcp.mss.floor', opt)
+    value = '48' if (tmp is None) else tmp
+    sysctl_write('net.ipv4.tcp_mtu_probe_floor', value)
+
     if 'protocol' in opt:
         zebra_daemon = 'zebra'
         # Save original configuration prior to starting any commit actions
-- 
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