Netsed

http://silicone.homelinux.org/git/netsed.git/, https://github.com/xlab/netsed

ipfwadm -I -i accept -S source_ip -D destination_ip port -P protocol -r lport   pfwadm is used to set up, maintain, and inspect the IP firewall and accounting rules in the Linux kernel. These rules can be divided into 4 different categories: accounting of IP packets, the IP input firewall, the IP output firewall, and the IP forwarding firewall. For each of these categories, a separate list of rules is maintained. See ipfw(4) for more details.

links
socat

https://www.stunnel.org/, https://github.com/mtrojnar/stunnel