Add SONiC Capirca generator README

PiperOrigin-RevId: 483875102

Author: Capirca Team

README.md

@@ -421,6 +421,7 @@ generators:
 *   [`packetfilter`](./doc/generators/packetfilter.md): PacketFilter
 *   [`paloaltofw`](./doc/generators/paloaltofw.md): Palo Alto PANOS
 *   [`pcap`](./doc/generators/pcap.md): PcapFilter
+*   [`sonic`](./doc/generators/sonic.md): SONiC ACLs in config_db.json format
 *   [`speedway`](./doc/generators/speedway.md): Speedway
 *   [`srxlo`](./doc/generators/srxlo.md): Stateless Juniper ACL
 *   [`windows_advfirewall`](./doc/generators/windows_advfirewall.md): Windows

doc/generators/sonic.md

@@ -0,0 +1,45 @@
+# SONiC
+
+The SONiC header designation has the following format:
+
+```
+target:: sonic filter-name {inet|inet6|mixed}
+```
+
+* _filter-name_: defines the name of the filter. This is a required field.
+  Note that the filter name will be present as a key of every ACE (i.e. rule) in
+  generated policy. For example if the filter-name is 'MyPolicy', each ACE will
+  come out like:
+
+  ```
+  {
+    'MyPolicy|RULE_10': {...},
+    'MyPolicy|RULE_20': {...},
+    ...
+  }
+  ```
+
+## Term Format
+
+* _action::_ The action to take when matched. See Actions section for valid
+  options.
+* _destination-address::_ One or more destination address tokens.
+* _destination-port::_ One or more service definition tokens.
+* _expiration::_ Stop rendering this term after specified date. Date format:
+  [YYYY](YYYY.md)-[MM](MM.md)-[DD](DD.md).
+* _protocol::_ The network protocols this term will match, such as tcp, udp, or
+  sctp.
+* _source-address::_ One or more source address tokens.
+* _source-port::_ One or more service definition tokens.
+
+## Sub Tokens
+
+### Actions
+
+* _accept_
+* _deny_
+
+### Option
+
+* _tcp-established::_ Only match "established" connections. It is not stateful -
+  any TCP packet with ACK and/or RST TCP flag set will match.