linux-cp: Add VPP->Linux synchronization

Part 1 -- notes in https://ipng.ch/s/articles/2021/08/13/vpp-2.html
Add the ability for VPP to copy out (sync) its state from the dataplane
to Linux Interface Pairs, when they exist. Gated by a configuration
flag (linux-cp { lcp-sync }), and by a CLI option to toggle on/off,
synchronize the following events:

- Interface state changes
- Interface MTU changes
- Interface IPv4/IPv6 address add/deletion

In VPP, subints can have any link state and MTU, orthogonal to their
phy. In Linux, setting admin-down on a phy forces its children to be
down as well. Also, in Linux, MTU of children must not exceed that of
the phy. Add a state synchronizer which walks over phy+subints to
ensure Linux and VPP end up in the same consistent state.

Part 2 -- notes in https://ipng.ch/s/articles/2021/08/15/vpp-3.html
Add the ability for VPP to autocreate sub-interfaces of existing Linux
Interface pairs. Gated by a configuration flag
(linux-cp { lcp-auto-subint }), and by a CLI option to toggle on/off,
synchronize the following event:

- Sub-interface creation (dot1q, dot1ad, QinQ and QinAD)

A few other changes:
- Add two functions into netlink.[ch] to delete ip4 and ip6 addresses.
- Remove a spurious logline (printing MTU) in netlink.c.
- Resolve a TODO around vnet_sw_interface_supports_addressing()

Type: improvement
Signed-off-by: Pim van Pelt <pim@ipng.nl>
Change-Id: I34fc070e80af4013be58d7a8cbf64296cc760e4e
Signed-off-by: Pim van Pelt <pim@ipng.nl>

1 files changed, 62 insertions, 0 deletions

diff --git a/src/plugins/linux-cp/lcp_cli.c b/src/plugins/linux-cp/lcp_cli.c
index cb874b1c023..8f2d17ab209 100644
--- a/src/plugins/linux-cp/lcp_cli.c
+++ b/src/plugins/linux-cp/lcp_cli.c
@@ -112,6 +112,68 @@ VLIB_CLI_COMMAND (lcp_itf_pair_create_command, static) = {
 };
 
 static clib_error_t *
+lcp_sync_command_fn (vlib_main_t *vm, unformat_input_t *input,
+		     vlib_cli_command_t *cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return 0;
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "on") || unformat (line_input, "enable"))
+	lcp_set_sync (1);
+      else if (unformat (line_input, "off") ||
+	       unformat (line_input, "disable"))
+	lcp_set_sync (0);
+      else
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, line_input);
+    }
+
+  unformat_free (line_input);
+  return 0;
+}
+
+VLIB_CLI_COMMAND (lcp_sync_command, static) = {
+  .path = "lcp lcp-sync",
+  .short_help = "lcp lcp-sync [on|enable|off|disable]",
+  .function = lcp_sync_command_fn,
+};
+
+static clib_error_t *
+lcp_auto_subint_command_fn (vlib_main_t *vm, unformat_input_t *input,
+			    vlib_cli_command_t *cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return 0;
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "on") || unformat (line_input, "enable"))
+	lcp_set_auto_subint (1);
+      else if (unformat (line_input, "off") ||
+	       unformat (line_input, "disable"))
+	lcp_set_auto_subint (0);
+      else
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, line_input);
+    }
+
+  unformat_free (line_input);
+  return 0;
+}
+
+VLIB_CLI_COMMAND (lcp_auto_subint_command, static) = {
+  .path = "lcp lcp-auto-subint",
+  .short_help = "lcp lcp-auto-subint [on|enable|off|disable]",
+  .function = lcp_auto_subint_command_fn,
+};
+
+static clib_error_t *
 lcp_default_netns_command_fn (vlib_main_t *vm, unformat_input_t *input,
 			      vlib_cli_command_t *cmd)
 {