47 lines
5.0 KiB
Markdown
47 lines
5.0 KiB
Markdown
# This is experimental
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The software is written in Rust (2018, safe mode only). At the current state I am having fun writing in Rust and testing language features. The code should be modular enough to change any function you deem awful enough.
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Error handling is subpar at the moment. There is no real unit testing to speak of since switching to asynchronous functionality. Testing will come back.
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This version is a successor of the _POSIX_C_SOURCE 200809L implementation in which all data parsed from a cap/pcapng files is written as a single and simple query. The ingestion time is rather fast (tested writes: 100*10^3 tcp packets in ~1.8 sec) but may be insecure. See the other repository for more information.
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The idea of this iteration is to use a prepared statement and chunk the data according to maximum input. Postgres databases have a custom maximum limit on each insert query of prepared statements. Said chunk size is initialized through the config/interface file called parser.json as `insert_max`. Data can be read from PCAP/PCANG files, as well as network devices.
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Process is as follows:
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- Choose between network device (specify it as well) or file input
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- Choosing device is straight forward -> data gets parsed, chunked and queries prepared according to `insert_max` size
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- Encapsulation type / Linktype is chosen in beforehand. Currently Ethernet and RawIp is supported.
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- Choosing file input means selecting a directory where your PCAP/PCAPNG files reside.
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- A hash map is created out of key(paths):value(metadata) out of pcap files found in the specified directory.
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- The parser gets invoked, which itself calls the appropriate protocol handler on to the byte data of packetsi yielded by pcap. A vector of type QryData is returned after EOF has been hit.
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- QryData vector is serialized.
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- Serialized data gets chunked.
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- Prepared statements are prepared according to chunksize
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- Queried data gets queried in chunks afterwards
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Currently, ethernet, IPv4, IPV6, TCP, UDP and ARP/RARP network protocols are handled.
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Because of testing purposes, layout of the table is serialized json. Table layout is somewhat "dynamic". Any procotols not recognized in a parsed packet will be marked as NULL inside a resulting table row.
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A query may look like this `select packet from json_dump where packet->>'ipv4_header' is not null;`
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Speaking of serialization: After profiling it turns out that ~20% of cpu time is used for serialization to json. This, of course, could be saved completely.
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Another subgoal was the ability to compile a static binary, which --last time I tested-- works without dependencies, but the need for libpcap itself. It even executes on oracle linux, after linking against the elf64 interpreter in a direct manner. If you ever had the pleasure using this derivate it may come as a suprise to you. The key is to compile via `x86_64-unknown-linux-musl` target. See: https://doc.rust-lang.org/edition-guide/rust-2018/platform-and-target-support/musl-support-for-fully-static-binaries.html
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Caveats: Regex Syntax is limited at the moment, because it is not compiled from a Rawstring, but a common one. Escaping does not work properly, character classes do. I have to fiddle the correct synctactical way to get it out of the json file and into a raw. For already supported regular expression syntax see: https://docs.rs/regex/1.3.9/regex/#syntax , also see the example in `parser.json`.
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Transmitting the data of the formerly described testing table layout results in a rather big table size. HDD space was no issue so far.
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If this whole thing turns out to be viable, some future features may be:
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- Database containing file hash map to compare file status/sizes after the parser may have crashed, or to join a complete overview of any existing PCAP files.
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- Concurrency. There are some interresting ways of parallelization I am working on to find a model that really benefits the use case. MPSC looks promising at the moment. Thats why tokio carte is already implemented for db queries, but has no performance benefit at the moment. Inplementing a MPSC pipe has the nice side effect of lower memory usage, parsed packages will directly be piped to json serialization function without beeing stored in a separate vector.
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- Update file hashmap through inotify crate, during runtime.
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- Restoration of fragmented ipv4 packages.
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- SIMD (via autovectorization). Which is easy enough to do in Rust.
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- Support of more protocols
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There are many other things left to be desired.
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The file used for testing was identical to the one used in the previous C implementation. Inserting none chunked data resulted in ~20 minutes of querying to database. Now, chunked data is below 20 seconds after compiler optimization.
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Speaking of optimization: Do yourself a favor an run release code not debug code: `cargo run --release`. The compiler does a rather hefty optimization and you will save some time waiting for your precious data do be inserted. I did no further optimization besides trying to enable the compiler to do a better job. Just blackboxing, no assembly tweaking yet.
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