[PATCH 2/2] Add net_set_vlan command

[Chad Kimes <chkimes@github.com>]

Previously there was no way to set the 802.1Q VLAN identifier, despite
support for vlantag in the net module. The only location vlantag was
being populated was from PXE boot and only for Open Firmware hardware.
This commit allows users to manually configure VLAN information for any
interface.

Example usage:
  grub> net_ls_addr
  efinet1 00:11:22:33:44:55 192.0.2.100
  grub> net_set_vlan efinet1 100
  grub> net_ls_addr
  efinet1 00:11:22:33:44:55 192.0.2.100 vlan100
  grub> net_set_vlan efinet1 0
  efinet1 00:11:22:33:44:55 192.0.2.100

Signed-off-by: Chad Kimes <chkimes@github.com>
---
 docs/grub.texi      | 19 +++++++++++++++++++
 grub-core/net/net.c | 42 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/docs/grub.texi b/docs/grub.texi
index caba8befb..b903bf1d1 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -5554,6 +5554,7 @@ This command is only available on AArch64 systems.
 * net_ls_dns::                  List DNS servers
 * net_ls_routes::               List routing entries
 * net_nslookup::                Perform a DNS lookup
+* net_set_vlan::                Set vlan id on an interface
 @end menu
 
 
@@ -5730,6 +5731,24 @@ is given, use default list of servers.
 @end deffn
 
 
+@node net_set_vlan
+@subsection net_set_vlan
+
+@deffn Command net_set_vlan @var{interface} @var{vlanid}
+Set the 802.1Q VLAN identifier on @var{interface} to @var{vlanid}. For example, to set the VLAN identifier on interface @samp{efinet1} to @samp{100}:
+
+@example
+net_set_vlan efinet1 100
+@end example
+
+The VLAN identifier can be removed by setting it to @samp{0}:
+
+@example
+net_set_vlan efinet1 0
+@end example
+@end deffn
+
+
 @node Internationalisation
 @chapter Internationalisation
 
diff --git a/grub-core/net/net.c b/grub-core/net/net.c
index b957b30e4..d79391c04 100644
--- a/grub-core/net/net.c
+++ b/grub-core/net/net.c
@@ -1176,6 +1176,43 @@ grub_cmd_addroute (struct grub_command *cmd __attribute__ ((unused)),
     }
 }
 
+static grub_err_t
+grub_cmd_setvlan (struct grub_command *cmd __attribute__ ((unused)),
+		  int argc, char **args)
+{
+  const char *vlan_string;
+  const char *vlan_string_end;
+  unsigned long vlantag;
+  struct grub_net_network_level_interface *inter;
+
+  if (argc != 2)
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("two arguments expected"));
+
+  vlan_string = args[1];
+  vlantag = grub_strtoul (vlan_string, &vlan_string_end, 10);
+
+  if (*vlan_string == '\0' || *vlan_string_end != '\0')
+    return grub_error (GRUB_ERR_BAD_NUMBER,
+		       N_("non-numeric or invalid number `%s'"), vlan_string);
+
+  if (vlantag > 4094)
+    return grub_error (GRUB_ERR_OUT_OF_RANGE,
+		       N_("vlan id `%s' not in the valid range of 0-4094"),
+		       vlan_string);
+
+  FOR_NET_NETWORK_LEVEL_INTERFACES (inter)
+    {
+      if (grub_strcmp (inter->name, args[0]) != 0)
+	continue;
+
+      inter->vlantag = vlantag;
+      return GRUB_ERR_NONE;
+    }
+
+  return grub_error (GRUB_ERR_BAD_ARGUMENT,
+                     N_("network interface not found"));
+}
+
 static void
 print_net_address (const grub_net_network_level_netaddress_t *target)
 {
@@ -1892,7 +1929,7 @@ grub_net_search_config_file (char *config)
 static struct grub_preboot *fini_hnd;
 
 static grub_command_t cmd_addaddr, cmd_deladdr, cmd_addroute, cmd_delroute;
-static grub_command_t cmd_lsroutes, cmd_lscards;
+static grub_command_t cmd_setvlan, cmd_lsroutes, cmd_lscards;
 static grub_command_t cmd_lsaddr, cmd_slaac;
 
 GRUB_MOD_INIT(net)
@@ -1930,6 +1967,9 @@ GRUB_MOD_INIT(net)
   cmd_delroute = grub_register_command ("net_del_route", grub_cmd_delroute,
 					N_("SHORTNAME"),
 					N_("Delete a network route."));
+  cmd_setvlan = grub_register_command ("net_set_vlan", grub_cmd_setvlan,
+				       N_("SHORTNAME VLANID"),
+				       N_("Set an interface's vlan id."));
   cmd_lsroutes = grub_register_command ("net_ls_routes", grub_cmd_listroutes,
 					"", N_("list network routes"));
   cmd_lscards = grub_register_command ("net_ls_cards", grub_cmd_listcards,
-- 
2.25.1