zebra: vlan to dplane Offload from main

Trigger: Zebra core seen when we convert l2vni to l3vni and back

BackTrace:
/usr/lib/x86_64-linux-gnu/frr/libfrr.so.0(_zlog_assert_failed+0xe9) [0x7f4af96989d9]
/usr/lib/frr/zebra(zebra_vxlan_if_vni_up+0x250) [0x5561022ae030]
/usr/lib/frr/zebra(netlink_vlan_change+0x2f4) [0x5561021fd354]
/usr/lib/frr/zebra(netlink_parse_info+0xff) [0x55610220d37f]
/usr/lib/frr/zebra(+0xc264a) [0x55610220d64a]
/usr/lib/x86_64-linux-gnu/frr/libfrr.so.0(thread_call+0x7d) [0x7f4af967e96d]
/usr/lib/x86_64-linux-gnu/frr/libfrr.so.0(frr_run+0xe8) [0x7f4af9637588]
/usr/lib/frr/zebra(main+0x402) [0x5561021f4d32]
/lib/x86_64-linux-gnu/libc.so.6(+0x2724a) [0x7f4af932624a]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x85) [0x7f4af9326305]
/usr/lib/frr/zebra(_start+0x21) [0x5561021f72f1]

Root Cause:
In working case,
 - We get a RTM_NEWLINK whose ctx is enqueued by zebra dplane and
   dequeued by zebra main and processed i.e.
   (102000 is deleted from vxlan99) before we handle RTM_NEWVLAN.
 - So in handling of NEWVLAN (vxlan99) we bail out since find with
   vlan id 703 does not exist.

root@leaf2:mgmt:/var/log/frr# cat ~/raja_logs/working/nocras.log  | grep "RTM_NEWLINK\|QUEUED\|vxlan99\|in thread"
2024/07/18 23:09:33.741105 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=616, seq=0, pid=0
2024/07/18 23:09:33.744061 ZEBRA: [K8FXY-V65ZJ] Intf dplane ctx 0x7f2244000cf0, op INTF_INSTALL, ifindex (65), result QUEUED
2024/07/18 23:09:33.767240 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=508, seq=0, pid=0
2024/07/18 23:09:33.767380 ZEBRA: [K8FXY-V65ZJ] Intf dplane ctx 0x7f2244000cf0, op INTF_INSTALL, ifindex (73), result QUEUED
2024/07/18 23:09:33.767389 ZEBRA: [NVFT0-HS1EX] INTF_INSTALL for vxlan99(73)
2024/07/18 23:09:33.767404 ZEBRA: [TQR2A-H2RFY] Vlan-Vni(1186:1186-6000002:6000002) update for VxLAN IF vxlan99(73)
2024/07/18 23:09:33.767422 ZEBRA: [TP4VP-XZ627] Del L2-VNI 102000 intf vxlan99(73)
2024/07/18 23:09:33.767858 ZEBRA: [QYXB9-6RNNK] RTM_NEWVLAN bridge IF vxlan99 NS 0
2024/07/18 23:09:33.767866 ZEBRA: [KKZGZ-8PCDW] Cannot find VNI for VID (703) IF vxlan99 for vlan state update >>>>BAIL OUT

In failure case,
 - The NEWVLAN is received first even before processing RTM_NEWLINK.
 - Since the vxlan id 102000 is not removed from the vxlan99,
   the find with vlan id 703 returns the 102000 one and we invoke
   zebra_vxlan_if_vni_up where the interfaces don't match and assert.

root@leaf2:mgmt:/var/log/frr# cat ~/raja_logs/noworking/crash.log | grep "RTM_NEWLINK\|QUEUED\|vxlan99\|in thread"
2024/07/18 22:26:43.829370 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=616, seq=0, pid=0
2024/07/18 22:26:43.829646 ZEBRA: [K8FXY-V65ZJ] Intf dplane ctx 0x7fe07c026d30, op INTF_INSTALL, ifindex (65), result QUEUED
2024/07/18 22:26:43.853930 ZEBRA: [QYXB9-6RNNK] RTM_NEWVLAN bridge IF vxlan99 NS 0
2024/07/18 22:26:43.853949 ZEBRA: [K61WJ-XQQ3X] Intf vxlan99(73) L2-VNI 102000 is UP >>> VLAN PROCESSED BEFORE INTF EVENT
2024/07/18 22:26:43.853951 ZEBRA: [SPV50-BX2RP] RAJA zevpn_vxlanif vxlan48 and ifp vxlan99
2024/07/18 22:26:43.854005 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=508, seq=0, pid=0
2024/07/18 22:26:43.854241 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=516, seq=0, pid=0
2024/07/18 22:26:43.854251 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=544, seq=0, pid=0
ZEBRA: in thread kernel_read scheduled from zebra/kernel_netlink.c:505 kernel_read()

Fix:
Similar to #13396, where link change
handling was offloaded to dplane, same is being done for vlan events.

Note: Prior to this change, zebra main thread was interested in the
RTNLGRP_BRVLAN. So all the kernel events pertaining to vlan was
handled by zebra main.

With this change change as well the handling of vlan events is still
with Zebra main. However we offload it via Dplane thread.

Ticket :#3878175

Signed-off-by: Rajasekar Raja <rajasekarr@nvidia.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/zebra/zebra_dplane.h b/zebra/zebra_dplane.h
index 0e9a8bfb99..3e143e8dba 100644
--- a/zebra/zebra_dplane.h
+++ b/zebra/zebra_dplane.h
@@ -24,6 +24,8 @@
 extern "C" {
 #endif
 
+DECLARE_MTYPE(VLAN_CHANGE_ARR);
+
 /* Retrieve the dataplane API version number; see libfrr.h to decode major,
  * minor, sub version values.
  * Plugins should pay attention to the major version number, at least, to
@@ -204,6 +206,9 @@ enum dplane_op_e {
 	DPLANE_OP_TC_FILTER_DELETE,
 	DPLANE_OP_TC_FILTER_UPDATE,
 
+	/* VLAN update */
+	DPLANE_OP_VLAN_INSTALL,
+
 	/* Startup Control */
 	DPLANE_OP_STARTUP_STAGE,
 
@@ -211,6 +216,13 @@ enum dplane_op_e {
 	DPLANE_OP_SRV6_ENCAP_SRCADDR_SET,
 };
 
+/* Operational status of Bridge Ports */
+#define ZEBRA_DPLANE_BR_STATE_DISABLED	 0x01
+#define ZEBRA_DPLANE_BR_STATE_LISTENING	 0x02
+#define ZEBRA_DPLANE_BR_STATE_LEARNING	 0x04
+#define ZEBRA_DPLANE_BR_STATE_FORWARDING 0x08
+#define ZEBRA_DPLANE_BR_STATE_BLOCKING	 0x10
+
 /*
  * The vxlan/evpn neighbor management code needs some values to use
  * when programming neighbor changes. Offer some platform-neutral values
@@ -1078,6 +1090,26 @@ void dplane_set_in_queue_limit(uint32_t limit, bool set);
 /* Retrieve the current queue depth of incoming, unprocessed updates */
 uint32_t dplane_get_in_queue_len(void);
 
+void dplane_ctx_set_vlan_ifindex(struct zebra_dplane_ctx *ctx,
+				 ifindex_t ifindex);
+ifindex_t dplane_ctx_get_vlan_ifindex(struct zebra_dplane_ctx *ctx);
+struct zebra_vxlan_vlan_array;
+
+/*
+ * In netlink_vlan_change(), the memory allocated for vlan_array is freed
+ * in two cases
+ *  1) Inline free in netlink_vlan_change() when there are no new
+ *     vlans to process i.e. nothing is enqueued to main thread.
+ *  2) Dplane-ctx takes over the vlan memory which gets freed in
+ *     rib_process_dplane_results() after handling the vlan install
+ *
+ * Note: MTYPE of interest for this purpose is MTYPE_VLAN_CHANGE_ARR
+ */
+void dplane_ctx_set_vxlan_vlan_array(struct zebra_dplane_ctx *ctx,
+				     struct zebra_vxlan_vlan_array *vlan_array);
+const struct zebra_vxlan_vlan_array *
+dplane_ctx_get_vxlan_vlan_array(struct zebra_dplane_ctx *ctx);
+
 /*
  * Vty/cli apis
  */