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cloudflare/wirefilter

Wirefilter

Build status Crates.io License

This is an execution engine for Wireshark®-like filters.

It contains public APIs for parsing filter syntax, compiling them into an executable IR and, finally, executing filters against provided values.

Example

use wirefilter::{ExecutionContext, Scheme}; fn main() -> Result<(), Box<dyn std::error::Error>> { // Create a map of possible filter fields. let scheme = Scheme! { http.method: Bytes, http.ua: Bytes, port: Int, } .build(); // Parse a Wireshark-like expression into an AST. let ast = scheme.parse( r#"  http.method != "POST" &&  not http.ua matches "(googlebot|facebook)" &&  port in {80 443}  "#, )?; println!("Parsed filter representation: {:?}", ast); // Compile the AST into an executable filter. let filter = ast.compile(); // Set runtime field values to test the filter against. let mut ctx = ExecutionContext::new(&scheme); ctx.set_field_value(scheme.get_field("http.method").unwrap(), "GET")?; ctx.set_field_value( scheme.get_field("http.ua").unwrap(), "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:66.0) Gecko/20100101 Firefox/66.0", )?; ctx.set_field_value(scheme.get_field("port").unwrap(), 443)?; // Execute the filter with given runtime values. println!("Filter matches: {:?}", filter.execute(&ctx)?); // true // Amend one of the runtime values and execute the filter again. ctx.set_field_value(scheme.get_field("port").unwrap(), 8080)?; println!("Filter matches: {:?}", filter.execute(&ctx)?); // false Ok(()) }

Fuzzing

There are fuzz tests in the fuzz directory.

Install afl:

cargo install afl --force 

Build bytes fuzz test:

cd fuzz/bytes cargo afl build 

Run fuzz test (from inside fuzz/bytes directory):

cargo afl fuzz -i in -o out ../../target/debug/fuzz-bytes 

If you see an error like:

Looks like the target binary is not instrumented! 

Try deleting the compiled binary and re-building with cargo afl build.

Licensing

Licensed under the MIT license. See the LICENSE file for details.

Packages

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