Add automatic LCP creation

Update the pair_config() parser to follow suite.

When the configuration 'lcp-auto-subint' is set, and the interface at
hand is a subinterface, in lcp_itf_interface_add_del():

- if it's a deletion and we're a sub-int, and we have a LIP: delete it.
- if it's a creation and we're a sub-int, and our parent has a LIP, create one.

Fix a few logging consistency issues (pair_del), and in
pair_delete_by_index() ensure that the right namespace is selected.

Due to this quirk with lip->lip_namespace not wanting to be a vec_dup()
string, rewrite them all to be strdup/free instead.

lcpng.c

@@ -69,6 +69,22 @@ int lcp_set_default_ns(u8 *ns) {
     return 0;
 }
 
+void
+lcp_set_auto_subint (u8 is_auto)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  lcpm->auto_subint = (is_auto != 0);
+}
+
+int
+lcp_auto_subint (void)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  return lcpm->auto_subint;
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *

lcpng.h

@@ -24,6 +24,7 @@ typedef struct lcp_main_s
   u16 msg_id_base;		    /* API message ID base */
   u8 default_namespace[LCP_NS_LEN]; /* default namespace if set */
   int default_ns_fd;
+  u8 auto_subint; /* Automatically create/delete LCP sub-interfaces */
   /* Set when Unit testing */
   u8 test_mode;
 } lcp_main_t;

lcpng_if_sync.c

@@ -452,14 +452,16 @@ static clib_error_t *
 lcp_itf_interface_add_del (vnet_main_t *vnm, u32 sw_if_index, u32 is_create)
 {
   const vnet_sw_interface_t *sw;
-  const lcp_itf_pair_t *sup_lip;
   uword is_sub;
 
   is_sub = vnet_sw_interface_is_sub (vnm, sw_if_index);
-  LCP_ITF_PAIR_DBG ("interface_%s: [%u] sw %U is_sub %u",
+  LCP_ITF_PAIR_DBG ("interface_%s: [%u] sw %U is_sub %u auto-subint %u",
 		    is_create ? "add" : "del", sw_if_index,
 		    format_vnet_sw_if_index_name, vnet_get_main (),
-		    sw_if_index, is_sub);
+		    sw_if_index, is_sub, lcp_auto_subint ());
+
+  if (!lcp_auto_subint ())
+    return NULL;
 
   sw = vnet_get_sw_interface_or_null (vnm, sw_if_index);
   if (!sw)
@@ -472,21 +474,39 @@ lcp_itf_interface_add_del (vnet_main_t *vnm, u32 sw_if_index, u32 is_create)
 		    sw->sw_if_index, format_vnet_sw_if_index_name,
 		    vnet_get_main (), sw->sup_sw_if_index);
 
-  // If the parent has a LIP and we're in auto-create, create a LIP for this
-  // child
-  sup_lip = lcp_itf_pair_get (lcp_itf_pair_find_by_phy (sw->sup_sw_if_index));
-  if (!sup_lip)
-    return NULL;
+  if (is_create)
+    {
+      const lcp_itf_pair_t *sup_lip;
+      u8 *name = 0;
 
-  LCP_ITF_PAIR_INFO (
-    "interface_%s: %U has parent %U, enqueueing creation of LCP",
-    is_create ? "add" : "del", format_vnet_sw_if_index_name, vnet_get_main (),
-    sw->sw_if_index, format_lcp_itf_pair, sup_lip);
+      // If the parent has a LIP auto-create a LIP for this interface
+      sup_lip =
+	lcp_itf_pair_get (lcp_itf_pair_find_by_phy (sw->sup_sw_if_index));
+      if (!sup_lip)
+	return NULL;
 
-  // We cannot create the interface here, because the previous interface for
-  // which this is a callback hasn't returned yet.
-  // lcp_itf_pair_create(sw->sw_if_index, (u8 *)"foo", LCP_ITF_HOST_TAP,
-  // sup_lip->lip_namespace, NULL);
+      name = format (name, "%s.%d", sup_lip->lip_host_name, sw->sub.id);
+
+      LCP_ITF_PAIR_INFO (
+	"interface_%s: %U has parent %U, auto-creating LCP with host-if %s",
+	is_create ? "add" : "del", format_vnet_sw_if_index_name,
+	vnet_get_main (), sw->sw_if_index, format_lcp_itf_pair, sup_lip, name);
+
+      lcp_itf_pair_create (sw->sw_if_index, name, LCP_ITF_HOST_TAP,
+			   sup_lip->lip_namespace, NULL);
+
+      vec_free (name);
+    }
+  else
+    {
+      const lcp_itf_pair_t *lip;
+
+      // If the interface has a LIP, auto-delete it
+      lip = lcp_itf_pair_get (lcp_itf_pair_find_by_phy (sw_if_index));
+      if (!lip)
+	return NULL;
+      lcp_itf_pair_delete (sw_if_index);
+    }
 
   return NULL;
 }

lcpng_interface.c

@@ -420,10 +420,11 @@ lcp_itf_pair_del (u32 phy_sw_if_index)
 
   lip = lcp_itf_pair_get (lipi);
 
-  LCP_ITF_PAIR_INFO ("pair delete: {%U, %U, %s}", format_vnet_sw_if_index_name,
-		     vnet_get_main (), lip->lip_phy_sw_if_index,
-		     format_vnet_sw_if_index_name, vnet_get_main (),
-		     lip->lip_host_sw_if_index, lip->lip_host_name);
+  LCP_ITF_PAIR_INFO (
+    "pair_del: host:%U phy:%U host_if:%s vif:%d ns:%s",
+    format_vnet_sw_if_index_name, vnet_get_main (), lip->lip_host_sw_if_index,
+    format_vnet_sw_if_index_name, vnet_get_main (), lip->lip_phy_sw_if_index,
+    lip->lip_host_name, lip->lip_vif_index, lip->lip_namespace);
 
   /* invoke registered callbacks for pair deletion */
   vec_foreach (vft, lcp_itf_vfts)
@@ -463,7 +464,8 @@ lcp_itf_pair_del (u32 phy_sw_if_index)
   hash_unset (lip_db_by_vif, lip->lip_vif_index);
 
   vec_free (lip->lip_host_name);
-  vec_free (lip->lip_namespace);
+  if (lip->lip_namespace)
+    free (lip->lip_namespace);
   pool_put (lcp_itf_pair_pool, lip);
 
   return 0;
@@ -474,24 +476,46 @@ lcp_itf_pair_delete_by_index (index_t lipi)
 {
   u32 host_sw_if_index;
   lcp_itf_pair_t *lip;
-  u8 *host_name;
+  u8 *host_name = 0;
+  char *ns = 0;
 
   lip = lcp_itf_pair_get (lipi);
 
   host_name = vec_dup (lip->lip_host_name);
+  ns = strdup ((const char *) lip->lip_namespace);
   host_sw_if_index = lip->lip_host_sw_if_index;
 
   lcp_itf_pair_del (lip->lip_phy_sw_if_index);
 
   if (vnet_sw_interface_is_sub (vnet_get_main (), host_sw_if_index))
     {
+      int curr_ns_fd = -1;
+      int vif_ns_fd = -1;
+      if (ns)
+	{
+	  curr_ns_fd = clib_netns_open (NULL /* self */);
+	  vif_ns_fd = clib_netns_open ((u8 *) ns);
+	  if (vif_ns_fd != -1)
+	    clib_setns (vif_ns_fd);
+	}
+
       lcp_netlink_del_link ((const char *) host_name);
+      if (vif_ns_fd != -1)
+	close (vif_ns_fd);
+
+      if (curr_ns_fd != -1)
+	{
+	  clib_setns (curr_ns_fd);
+	  close (curr_ns_fd);
+	}
+
       vnet_delete_sub_interface (host_sw_if_index);
     }
   else
     tap_delete_if (vlib_get_main (), host_sw_if_index);
 
   vec_free (host_name);
+  free (ns);
 }
 
 int
@@ -524,29 +548,30 @@ lcp_itf_pair_walk (lcp_itf_pair_walk_cb_t cb, void *ctx)
 static clib_error_t *
 lcp_itf_pair_config (vlib_main_t *vm, unformat_input_t *input)
 {
-  u8 *phy;
-  u8 *ns;
-  u8 *netns;
+  u8 *default_ns;
 
-  phy = ns = netns = NULL;
+  default_ns = NULL;
 
   while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
     {
-      if (unformat (input, "netns %v", &netns))
+      if (unformat (input, "default netns %v", &default_ns))
 	{
-	  vec_add1 (netns, 0);
-          if (lcp_set_default_ns(netns) < 0) {
-            return clib_error_return(
-                0, "lcpng namespace must be less than %d characters",
-                LCP_NS_LEN);
-          }
-        }
+	  vec_add1 (default_ns, 0);
+	  if (lcp_set_default_ns (default_ns) < 0)
+	    {
+	      return clib_error_return (
+		0, "linux-cp namespace must be less than %d characters",
+		LCP_NS_LEN);
+	    }
+	}
+      else if (unformat (input, "lcp-auto-subint"))
+	lcp_set_auto_subint (1 /* is_auto */);
       else
-	return clib_error_return (0, "interfaces not found");
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, input);
     }
 
-  vec_free (phy);
-  vec_free (netns);
+  vec_free (default_ns);
 
   return NULL;
 }

lcpng_interface.h

@@ -164,6 +164,12 @@ lcp_itf_pair_find_by_host (u32 host_sw_if_index)
   return (lip_db_by_host[host_sw_if_index]);
 }
 
+/**
+ * sub-interface auto creation/deletion for LCP
+ */
+void lcp_set_auto_subint (u8 is_auto);
+int lcp_auto_subint (void);
+
 typedef void (*lcp_itf_pair_add_cb_t) (lcp_itf_pair_t *);
 typedef void (*lcp_itf_pair_del_cb_t) (lcp_itf_pair_t *);