Create README.md

README.md

+# BPF Compiler Collection (BCC)
+
+This directory contains source code for BCC, a toolkit for creating small
+programs that can be dynamically loaded into a Linux kernel.
+
+The compiler relies upon eBPF (Extended Berkeley Packet Filters), which is a
+feature in Linux kernels starting from 3.19. Currently, this compiler leverages
+features which are mostly available in Linux 4.1 and above.
+
+## Motivation
+
+BPF guarantees that the programs loaded into the kernel cannot crash, and
+cannot run forever, but yet BPF is general purpose enough to perform many 
+arbitrary types of computation. Currently, it is possible to write a program in 
+C that will compile into a valid BPF program, yet it is vastly easier to
+write a C program that will compile into invalid BPF (C is like that). The user
+won't know until trying to run the program whether it was valid or not. 
+
+With a BPF-specific frontend, one should be able to write in a language and
+receive feedback from the compiler on the validity as it pertains to a BPF
+backend. This toolkit aims to provide a frontend that can only create valid BPF
+programs while still harnessing its full flexibility.
+
+The features of this toolkit include:
+* End-to-end BPF workflow in a shared library
+  * The B language - a C-like language for BPF backends
+  * Integration with llvm-bpf backend for JIT 
+  * Dynamic (un)loading of JITed programs
+  * Support for BPF kernel hooks: socket filters, tc classifiers,
+      tc actions, and kprobes
+* Bindings for Python
+* Examples for socket filters, tc classifiers, and kprobes
+* Test cases!
+
+## Requirements
+
+To get started using this toolchain, one needs:
+* Linux kernel 4.1 or newer, with these flags enabled:
+  * CONFIG_BPF=y
+  * CONFIG_BPF_SYSCALL=y
+  * CONFIG_NET_CLS_BPF=m [optional, for tc filters]
+  * CONFIG_NET_ACT_BPF=m [optional, for tc actions]
+  * CONFIG_BPF_JIT=y
+  * CONFIG_HAVE_BPF_JIT=y
+  * CONFIG_BPF_EVENTS=y [optional, for kprobes]
+* LLVM 3.7 or newer, compiled with BPF support (currently experimental)
+* Clang 3.5 or newer (this requirement is orthoganal to the LLVM requirement,
+                      and the versions do not necessarily need to match) 
+* cmake, gcc-4.9, flex, bison, xxd, libstdc++-static, libmnl-devel
+
+## Release notes
+
+* 0.1
+  * Initial commit