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Central Regulatory Domain Agent (CRDA) ======================================== This is the Central Regulatory Domain Agent for Linux. It serves one purpose: tell Linux kernel what to enforce. In essence it is a udev helper for communication between the kernel and userspace. You only need to run this manually for debugging purposes. For manual changing of regulatory domains use iw (iw reg set) or wpa_supplicant (feature yet to be added). HOST REQUIREMENTS =================== CRDA is provided as a binary file so all the host needs is libc/uclibc. You will also need udev and at least libnl1. BUILD REQUIREMENTS ==================== The package build requirements currently are: * python and the m2crypto package (python-m2crypto) * libgcrypt or libssl (openssl) header files * nl library and header files (libnl1 and libnl-dev) available at git://git.kernel.org/pub/scm/libs/netlink/libnl.git * RSA public key of John Linville and Seth Forshee, we include these as part of this package so you do not need to install it. The RSA public keys comes from the wireless-regdb.git tree and we keep them up to date here. * regulatory database, clone this tree: git://git.kernel.org/pub/scm/linux/kernel/git/sforshee/wireless-regdb.git and then stuff regulatory.bin (no need to build) provided there in REG_BIN location specified in this Makefile. This regulatory.bin file is only required to verify the CRDA built here can read its database file which has been signed with the RSA private key. CALLING CRDA -- UDEV ====================== Distributions can set up a udev rule to allow the kernel's regulatory domain change request to be reviewed by CRDA so CRDA can pass an appropriate regulatory domain. An example regulatory rule is provided with this package as regulatory.rules OVERVIEW ========== The database is maintained on the wireless-regdb.git tree. This git tree maintains a binary regulatory database file which is produced using its own ASCII db.txt into binary form for size efficiency. The contents of the binary database are then signed using the private key. CRDA will use regulatory.bin if its signature checks out with the public key provided. This will prevent us from using corrupted data (in case of hard drive failure) in the running kernel. This separation between CRDA and the regulatory database also allows us to provide regulatory updates on distributions without having to require an update on CRDA. Note that upon updating the regulatory database it is advised the user reboots or all the wireless modules get unloaded and reloaded. Under certain circumstances it may be desirable to have the regulatory agent accept multiple keys, this can be achieved by stuffing all the keys desired into pubkeys. Right now we use John Linville's and Seth Forshee's public keys. REGDB AUTHORS =============== Authors of regulatory.bin first need a private key, which can be generated with something like this: openssl genrsa -out your.key.priv.pem 2048 You'll then need to generate the public key and publish it. You can generate it as follows: openssl rsa -in your.key.priv.pem -out your.key.pub.pem -pubout -outform PEM Then with this key you can generate regulatory.bin files like this: ./utils/db2bin.py regulatory.bin db.txt your.key.priv.pem MAGIC PATTERN =============== Use the following magic(5) pattern to recognise CRDA binary regulatory database files: ---- %< ---- # CRDA Regulatory database file # http://git.kernel.org/?p=linux/kernel/git/mcgrof/crda.git;a=summary # (see regdb.h) 0 belong 0x52474442 CRDA regulatory database file >4 belong 19 (Version 1) ---- >% ----