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>

src/plugins/linux-cp/CMakeLists.txt

@@ -27,6 +27,7 @@ include_directories(${LIBMNL_INCLUDE_DIR})
 add_vpp_library(lcp
   SOURCES
   lcp_interface.c
+  lcp_interface_sync.c
   lcp_adj.c
   lcp.c
 

src/plugins/linux-cp/lcp.c

@@ -20,6 +20,7 @@
 #include <net/if.h>
 
 #include <plugins/linux-cp/lcp.h>
+#include <plugins/linux-cp/lcp_interface.h>
 
 lcp_main_t lcp_main;
 
@@ -76,6 +77,42 @@ lcp_set_default_ns (u8 *ns)
   return 0;
 }
 
+void
+lcp_set_sync (u8 is_auto)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  lcpm->lcp_sync = (is_auto != 0);
+
+  // If we set to 'on', do a one-off sync of LCP interfaces
+  if (is_auto)
+    lcp_itf_pair_sync_state_all ();
+}
+
+int
+lcp_sync (void)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  return lcpm->lcp_sync;
+}
+
+void
+lcp_set_auto_subint (u8 is_auto)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  lcpm->lcp_auto_subint = (is_auto != 0);
+}
+
+int
+lcp_auto_subint (void)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  return lcpm->lcp_auto_subint;
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *

src/plugins/linux-cp/lcp.h

@@ -24,8 +24,9 @@ typedef struct lcp_main_s
   u16 msg_id_base;		    /* API message ID base */
   u8 *default_namespace;	    /* default namespace if set */
   int default_ns_fd;
-  /* Set when Unit testing */
-  u8 test_mode;
+  u8 lcp_auto_subint; /* Automatically create/delete LCP sub-interfaces */
+  u8 lcp_sync;	      /* Automatically sync VPP changes to LCP */
+  u8 test_mode;	      /* Set when Unit testing */
 } lcp_main_t;
 
 extern lcp_main_t lcp_main;

src/plugins/linux-cp/lcp_cli.c

@@ -111,6 +111,68 @@ VLIB_CLI_COMMAND (lcp_itf_pair_create_command, static) = {
   .function = lcp_itf_pair_create_command_fn,
 };
 
+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)

src/plugins/linux-cp/lcp_interface.h

@@ -21,6 +21,22 @@
 
 #include <plugins/linux-cp/lcp.h>
 
+extern vlib_log_class_t lcp_itf_pair_logger;
+
+#define LCP_ITF_PAIR_DBG(...)                                                 \
+  vlib_log_debug (lcp_itf_pair_logger, __VA_ARGS__);
+
+#define LCP_ITF_PAIR_INFO(...)                                                \
+  vlib_log_info (lcp_itf_pair_logger, __VA_ARGS__);
+
+#define LCP_ITF_PAIR_NOTICE(...)                                              \
+  vlib_log_notice (lcp_itf_pair_logger, __VA_ARGS__);
+
+#define LCP_ITF_PAIR_WARN(...)                                                \
+  vlib_log_warn (lcp_itf_pair_logger, __VA_ARGS__);
+
+#define LCP_ITF_PAIR_ERR(...) vlib_log_err (lcp_itf_pair_logger, __VA_ARGS__);
+
 #define foreach_lcp_itf_pair_flag _ (STALE, 0, "stale")
 
 typedef enum lip_flag_t_
@@ -88,8 +104,6 @@ extern index_t lcp_itf_pair_find_by_vif (u32 vif_index);
 extern int lcp_itf_pair_add (u32 host_sw_if_index, u32 phy_sw_if_index,
 			     u8 *host_name, u32 host_index,
 			     lip_host_type_t host_type, u8 *ns);
-extern int lcp_itf_pair_add_sub (u32 vif, u8 *host_name, u32 sub_sw_if_index,
-				 u32 phy_sw_if_index, u8 *ns);
 extern int lcp_itf_pair_del (u32 phy_sw_if_index);
 
 /**
@@ -144,12 +158,6 @@ lcp_itf_pair_find_by_host (u32 host_sw_if_index)
   return (lip_db_by_host[host_sw_if_index]);
 }
 
-/**
- * manage interface auto creation
- */
-void lcp_set_auto_intf (u8 is_auto);
-int lcp_auto_intf (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 *);
 
@@ -160,6 +168,36 @@ typedef struct lcp_itf_pair_vft
 } lcp_itf_pair_vft_t;
 
 void lcp_itf_pair_register_vft (lcp_itf_pair_vft_t *lcp_itf_vft);
+
+/**
+ * sub-interface auto creation/deletion for LCP
+ */
+void lcp_set_auto_subint (u8 is_auto);
+int lcp_auto_subint (void);
+
+/**
+ * sync state changes from VPP into LCP
+ */
+void lcp_set_sync (u8 is_auto);
+int lcp_sync (void);
+
+/* Set TAP and Linux host link state */
+void lcp_itf_set_link_state (const lcp_itf_pair_t *lip, u8 state);
+
+/* Set any VPP L3 addresses on Linux host device */
+void lcp_itf_set_interface_addr (const lcp_itf_pair_t *lip);
+
+/* Sync all state from VPP to a specific Linux device, all sub-interfaces
+ * of a hardware interface, or all interfaces in the system.
+ *
+ * Note: in some circumstances, this syncer will (have to) make changes to
+ * the VPP interface, for example if its MTU is greater than its parent.
+ * See the function for rationale.
+ */
+void lcp_itf_pair_sync_state (lcp_itf_pair_t *lip);
+void lcp_itf_pair_sync_state_hw (vnet_hw_interface_t *hi);
+void lcp_itf_pair_sync_state_all ();
+
 /*
  * fd.io coding-style-patch-verification: ON
  *

src/vnet/devices/netlink.c

@@ -273,7 +273,6 @@ vnet_netlink_get_link_mtu (int ifindex, u32 *mtu)
 	    *mtu = clib_net_to_host_u32 (msg_mtu);
 	  else
 	    *mtu = msg_mtu;
-	  clib_warning ("mtu: %d", *mtu);
 	  goto done;
 	}
       offset = NLA_ALIGN (attr->nla_len);
@@ -409,6 +408,50 @@ vnet_netlink_add_ip6_route (void *dst, u8 dst_len, void *gw)
   return err;
 }
 
+clib_error_t *
+vnet_netlink_del_ip4_addr (int ifindex, void *addr, int pfx_len)
+{
+  vnet_netlink_msg_t m;
+  struct ifaddrmsg ifa = { 0 };
+  clib_error_t *err = 0;
+
+  ifa.ifa_family = AF_INET;
+  ifa.ifa_prefixlen = pfx_len;
+  ifa.ifa_index = ifindex;
+
+  vnet_netlink_msg_init (&m, RTM_DELADDR, NLM_F_REQUEST, &ifa,
+			 sizeof (struct ifaddrmsg));
+
+  vnet_netlink_msg_add_rtattr (&m, IFA_LOCAL, addr, 4);
+  vnet_netlink_msg_add_rtattr (&m, IFA_ADDRESS, addr, 4);
+  err = vnet_netlink_msg_send (&m, NULL);
+  if (err)
+    err = clib_error_return (0, "del ip4 addr %U", format_clib_error, err);
+  return err;
+}
+
+clib_error_t *
+vnet_netlink_del_ip6_addr (int ifindex, void *addr, int pfx_len)
+{
+  vnet_netlink_msg_t m;
+  struct ifaddrmsg ifa = { 0 };
+  clib_error_t *err = 0;
+
+  ifa.ifa_family = AF_INET6;
+  ifa.ifa_prefixlen = pfx_len;
+  ifa.ifa_index = ifindex;
+
+  vnet_netlink_msg_init (&m, RTM_DELADDR, NLM_F_REQUEST, &ifa,
+			 sizeof (struct ifaddrmsg));
+
+  vnet_netlink_msg_add_rtattr (&m, IFA_LOCAL, addr, 16);
+  vnet_netlink_msg_add_rtattr (&m, IFA_ADDRESS, addr, 16);
+  err = vnet_netlink_msg_send (&m, NULL);
+  if (err)
+    err = clib_error_return (0, "del ip6 addr %U", format_clib_error, err);
+  return err;
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *

src/vnet/devices/netlink.h

@@ -26,8 +26,10 @@ clib_error_t *vnet_netlink_get_link_mtu (int ifindex, u32 *mtu);
 clib_error_t *vnet_netlink_set_link_mtu (int ifindex, int mtu);
 clib_error_t *vnet_netlink_add_ip4_addr (int ifindex, void *addr,
 					 int pfx_len);
+clib_error_t *vnet_netlink_del_ip4_addr (int ifindex, void *addr, int pfx_len);
 clib_error_t *vnet_netlink_add_ip6_addr (int ifindex, void *addr,
 					 int pfx_len);
+clib_error_t *vnet_netlink_del_ip6_addr (int ifindex, void *addr, int pfx_len);
 clib_error_t *vnet_netlink_add_ip4_route (void *dst, u8 dst_len, void *gw);
 clib_error_t *vnet_netlink_add_ip6_route (void *dst, u8 dst_len, void *gw);