Update release note for 1.21.

Author: jfb8856606

doc/F-Stack_Release_Note.md

@@ -2,6 +2,49 @@
 
  F-Stack is an open source network framework based on DPDK.
 
+2021.01 F-Stack v1.21
+
+    1. F-Stack lib:
+  - Fix use after free issue in mbuf free. #565 #556 @tanjianfeng @zouyonghao @freak82
+  - Fix insufficient condition in ff_rte_frm_extcl function.
+  - Fix wrong msg_flags in struct msghdr after calling ff_recvmsg in a Linux application.
+  - Modify dump codes. @jinhao2
+  - Feature knictl. @pengtianabc
+  - Add configuration options `symmetric_rss` to set whether to use symmetric RSS.
+  - Add IPv6 net addr parameters in config. @zengyi1001
+  - Add `ff_regist_pcblddr_fun` to regist a pcb lddr function in F-Stack.
+  - Config: Support parse "--file-prefix"&"--pci-whitelist" for multi-processes. @hawkxiang
+  - Support rte_flow_isolate for multi lcore. @hawkxiang
+
+  2. Nginx:
+
+  - Fix some issues of nginx transparent proxy. @rolfliu
+
+  3. micro_thread:
+
+  - Add micro_thread_auto_adjust_thread_cnt. @WoolenWang
+  - Fix compile error of micro_thread with gcc 8.3. @Xin Wang
+
+  4. Tools:
+
+  - Fix a crash bug while use `ff_ifconfig`.
+  - Fix bug of `ff_sysctl`.
+  - Fix some other bugs while use ff msg.
+  - IPFW: supported IPv6. @zjwsoft
+  - Add ff_ipc_exit() to clean temp files in /var/ while run F-Stack tools arp/ifconfig/route/ipfw. @zjwsoft
+  - Add ndp tool for ipv6 neighbor. @chopin11
+
+
+  5. DPDK:
+
+  - Upgrade to 19.11.5 LTS.
+
+  6. Others:
+
+  - Update README.md. @soroshsabz
+
+
+
 2019.11 F-Stack v1.20
 
   1. F-Stack lib:
@@ -16,7 +59,7 @@
   - Add bonding suopported. *Note: some bond driver can not work with multi processes.*
   - Add `pkt_tx_delay` parameter in `config.ini`.
   - Add `tx_csum_offoad_skip` parameter in `config.ini`. @JayathS
-  
+
   2. Nginx:
 
   - Upgrade to 1.16.1.