A combination or sed(1), gawk(1) and a C program for parsing Ethernet MAC addresses from a file and lookup the vendor of the chip

oui.sh is the driving script, it accepts 2 arguments, the 2nd is optional, the first is the file where the mac addresses are, and the second if it is "-d" it will use the httpoui.c http client to download the oui.txt from the IEEE. The oui.txt contain a list of OUI (3 octets) that list the vendor assignated to that OUI by the IEEE.

IF the file oui.txt doesn't exist and no "-d" parameter was passed then the script will use a gawk(1) socket to make an http request to download the file, if "-d" was passed the script will use make(1) to build the http client and use it to download the oui.txt file. After that sed(1) takes care to do some cleanups and then hand the data over to gawk(1) via a pipe(2) to continue filtering, finally after all is done the OUIs on the input mac file will be matched against the OUIs in the oui.txt file to find the vendor.

NOTE: this small hobby project is developed on FreeBSD 11.2 for that reason the http client in C might not build or work on any other unix-like OS since it make uses of at least one FreeBSD specific flag for getaddrinfo(2) I plan to fix this soon, it works, however in OpenBSD and NetBSD but not on Linux.

Orestes Leal Rodriguez, 2018 olealrd1981@gmail.com