query for snort signature writing using if condition

[Ngnr Pu via Snort-users <snort-users () lists snort org>]

i want to write a rule based on if condition. Any solution or hint please?

_______________________________________________
Snort-users mailing list
Snort-users () lists snort org
Go to this URL to change user options or unsubscribe:
https://lists.snort.org/mailman/listinfo/snort-users

Please visit http://blog.snort.org to stay current on all the latest Snort news!

Please follow these rules: https://snort.org/faq/what-is-the-mailing-list-etiquette