lwIP

lwIP is a small independent implementation of the TCP/IP protocol suite, initially developed by Adam Dunkels.

The focus of the lwIP TCP/IP implementation is to reduce resource usage while still providing full-scale TCP. This makes lwIP suitable for use in embedded systems with as little as 10s of KBs of free RAM and 40 KB of code ROM. Main features include:

• Protocols: IP, ICMP, UDP, TCP, IGMP, ARP, PPPoS, PPPoE.

• DHCP client, DNS client, AutoIP/APIPA (Zeroconf), SNMP agent (private MIB support).

• APIs: specialized APIs for enhanced performance, optional Berkeley-like socket API.

• Extended features: IP forwarding over multiple network interfaces, TCP congestion control, RTT estimation, and fast recovery/fast retransmit.

• Add-on applications: HTTP server, SNTP client, SMTP client, ping, NetBIOS nameserver.

lwIP is licensed under a BSD-style license: https://lwip.fandom.com/wiki/License.