T8534: refactor sysctl_(read|write) to accept key parts

Interface names can contain dots (e.g. VLAN subinterfaces like eth0.10), which
conflicts with sysctl's dot-separated key syntax.

Change sysctl_read() and sysctl_write() to take key components as a list and
normalize each component by replacing . with / before invoking sysctl. This
fixes sysctl lookups/updates for VLAN subinterfaces.

Extend the SR-TE smoketest to cover a VLAN subinterface.

Previous error raising this issue:
  vyos-configd: sysctl: cannot stat /proc/sys/net/ipv6/conf/eth0/10/seg6_enabled: No such file or directory
  vyos-configd: sysctl: cannot stat /proc/sys/net/ipv6/conf/eth0/201/seg6_enabled: No such file or directory

1 files changed, 8 insertions, 8 deletions

diff --git a/src/conf_mode/system_ip.py b/src/conf_mode/system_ip.py
index 13471eb3b..6aff982d7 100755
--- a/src/conf_mode/system_ip.py
+++ b/src/conf_mode/system_ip.py
@@ -75,20 +75,20 @@ def apply(config_dict):
     # table_size has a default value - thus the key always exists
     size = int(dict_search('arp.table_size', opt))
     # Amount upon reaching which the records begin to be cleared immediately
-    sysctl_write('net.ipv4.neigh.default.gc_thresh3', size)
+    sysctl_write(['net', 'ipv4', 'neigh', 'default', 'gc_thresh3'], size)
     # Amount after which the records begin to be cleaned after 5 seconds
-    sysctl_write('net.ipv4.neigh.default.gc_thresh2', size // 2)
+    sysctl_write(['net', 'ipv4', 'neigh', 'default', 'gc_thresh2'], size // 2)
     # Minimum number of stored records is indicated which is not cleared
-    sysctl_write('net.ipv4.neigh.default.gc_thresh1', size // 8)
+    sysctl_write(['net', 'ipv4', 'neigh', 'default', 'gc_thresh1'], size // 8)
 
     # configure multipath
     tmp = dict_search('multipath.ignore_unreachable_nexthops', opt)
     value = '1' if (tmp != None) else '0'
-    sysctl_write('net.ipv4.fib_multipath_use_neigh', value)
+    sysctl_write(['net', 'ipv4', 'fib_multipath_use_neigh'], value)
 
     tmp = dict_search('multipath.layer4_hashing', opt)
     value = '1' if (tmp != None) else '0'
-    sysctl_write('net.ipv4.fib_multipath_hash_policy', value)
+    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)
@@ -101,15 +101,15 @@ def apply(config_dict):
     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)
+    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)
+    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)
+    sysctl_write(['net', 'ipv4', 'tcp_mtu_probe_floor'], value)
 
     # During startup of vyos-router that brings up FRR, the service is not yet
     # running when this script is called first. Skip this part and wait for initial