Async tokio runtime with modular architecture #1
59
CLAUDE.md
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59
CLAUDE.md
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# CLAUDE.md
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This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
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## Overview
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A DNS forwarding/caching proxy in Rust. Serves local zone records from TOML config, caches upstream responses with TTL-based expiration, forwards unknown queries to an upstream resolver, and logs all queries with structured output.
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## Build & Run
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```bash
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cargo build # compile
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sudo cargo run # run with default config (dns_fun.toml)
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sudo cargo run -- path/to/config # run with custom config path
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RUST_LOG=debug sudo cargo run # verbose logging
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```
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Test with: `dig @127.0.0.1 google.com`
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No tests or linter configured.
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## Architecture
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```
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src/
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lib.rs # module declarations, Error/Result type aliases
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main.rs # startup, config load, UDP listen loop, request pipeline
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buffer.rs # BytePacketBuffer — 512-byte DNS wire format read/write
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header.rs # DnsHeader, ResultCode — 12-byte header bitfield parsing
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question.rs # DnsQuestion, QueryType — query section (A, NS, CNAME, MX, AAAA)
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record.rs # DnsRecord — resource record variants with read/write
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packet.rs # DnsPacket — top-level: header + questions + answers + authorities + resources
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config.rs # Config loading from TOML, zone map builder
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cache.rs # DnsCache — TTL-aware cache with lazy eviction
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forward.rs # forward_query() — sends query to upstream, build_servfail() — error response
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stats.rs # ServerStats — query counters and periodic summary
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```
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## Request Pipeline
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```
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Query → Parse → Log → Local Zones → Cache → Upstream Forward (+ cache result) → Log → Respond
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```
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## Config
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`dns_fun.toml` at project root. Sections: `[server]`, `[upstream]`, `[cache]`, `[[zones]]`. Falls back to sensible defaults if file is missing.
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## Logging
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Controlled via `RUST_LOG` env var. Default level: `info` (one structured line per query). `debug` adds response details. Stats summary every 1000 queries.
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## Key Details
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- Rust 2018 edition, deps: `serde`, `toml`, `log`, `env_logger`
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- DNS packet size limited to 512 bytes (standard UDP DNS)
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- `BytePacketBuffer::read_qname` handles label compression (pointer jumps)
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- `type Error = Box<dyn std::error::Error>` / `type Result<T>` aliased in `lib.rs`
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- Cache: TTL clamped between `min_ttl` and `max_ttl`, lazy eviction every 1000 queries
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425
Cargo.lock
generated
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425
Cargo.lock
generated
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@@ -0,0 +1,425 @@
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# This file is automatically @generated by Cargo.
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# It is not intended for manual editing.
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version = 4
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|
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||||
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||||
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||||
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||||
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||||
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||||
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dependencies = [
|
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"env_logger",
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"log",
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"serde",
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"tokio",
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"toml",
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]
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[[package]]
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|
||||
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|
||||
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||||
"env_filter",
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"jiff",
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"log",
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[[package]]
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name = "equivalent"
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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|
||||
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|
||||
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|
||||
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|
||||
|
||||
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|
||||
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||||
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||||
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|
||||
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|
||||
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||||
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||||
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|
||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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||||
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|
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|
||||
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|
||||
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|
||||
|
||||
[[package]]
|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
|
||||
[[package]]
|
||||
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|
||||
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|
||||
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|
||||
checksum = "dc1beb996b9d83529a9e75c17a1686767d148d70663143c7854d8b4a09ced362"
|
||||
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|
||||
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|
||||
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|
||||
"toml_datetime",
|
||||
"toml_edit",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
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|
||||
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||||
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|
||||
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|
||||
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|
||||
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|
||||
|
||||
[[package]]
|
||||
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|
||||
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||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "41fe8c660ae4257887cf66394862d21dbca4a6ddd26f04a3560410406a2f819a"
|
||||
dependencies = [
|
||||
"indexmap",
|
||||
"serde",
|
||||
"serde_spanned",
|
||||
"toml_datetime",
|
||||
"toml_write",
|
||||
"winnow",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "toml_write"
|
||||
version = "0.1.2"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "5d99f8c9a7727884afe522e9bd5edbfc91a3312b36a77b5fb8926e4c31a41801"
|
||||
|
||||
[[package]]
|
||||
name = "unicode-ident"
|
||||
version = "1.0.24"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
|
||||
|
||||
[[package]]
|
||||
name = "utf8parse"
|
||||
version = "0.2.2"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
|
||||
|
||||
[[package]]
|
||||
name = "wasi"
|
||||
version = "0.11.1+wasi-snapshot-preview1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
|
||||
|
||||
[[package]]
|
||||
name = "windows-link"
|
||||
version = "0.2.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
|
||||
|
||||
[[package]]
|
||||
name = "windows-sys"
|
||||
version = "0.61.2"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
|
||||
dependencies = [
|
||||
"windows-link",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "winnow"
|
||||
version = "0.7.15"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "df79d97927682d2fd8adb29682d1140b343be4ac0f08fd68b7765d9c059d3945"
|
||||
dependencies = [
|
||||
"memchr",
|
||||
]
|
||||
@@ -7,3 +7,8 @@ edition = "2018"
|
||||
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
|
||||
|
||||
[dependencies]
|
||||
tokio = { version = "1", features = ["rt-multi-thread", "macros", "net", "time"] }
|
||||
toml = "0.8"
|
||||
serde = { version = "1", features = ["derive"] }
|
||||
log = "0.4"
|
||||
env_logger = "0.11"
|
||||
|
||||
121
README.md
121
README.md
@@ -1 +1,122 @@
|
||||
# dns_fun
|
||||
|
||||
A DNS forwarding/caching proxy written from scratch in Rust. Parses and serializes DNS wire protocol (RFC 1035), serves local zone records from TOML config, caches upstream responses with TTL-aware expiration, and logs every query with structured output.
|
||||
|
||||
No async runtime, no DNS libraries — just `std::net::UdpSocket` and manual packet parsing.
|
||||
|
||||
## Record Types
|
||||
|
||||
A, NS, CNAME, MX, AAAA
|
||||
|
||||
## Usage
|
||||
|
||||
```bash
|
||||
# Run with default config (dns_fun.toml)
|
||||
sudo cargo run
|
||||
|
||||
# Run with custom config path
|
||||
sudo cargo run -- path/to/config.toml
|
||||
|
||||
# Test
|
||||
dig @127.0.0.1 google.com
|
||||
dig @127.0.0.1 mysite.local
|
||||
```
|
||||
|
||||
Requires root/sudo for binding to port 53.
|
||||
|
||||
## Configuration
|
||||
|
||||
Edit `dns_fun.toml`:
|
||||
|
||||
```toml
|
||||
[server]
|
||||
bind_addr = "0.0.0.0:53"
|
||||
|
||||
[upstream]
|
||||
address = "8.8.8.8"
|
||||
port = 53
|
||||
timeout_ms = 3000
|
||||
|
||||
[cache]
|
||||
max_entries = 10000
|
||||
min_ttl = 60 # floor: cache at least 60s
|
||||
max_ttl = 86400 # ceiling: never cache longer than 24h
|
||||
|
||||
[[zones]]
|
||||
domain = "mysite.local"
|
||||
record_type = "A"
|
||||
value = "127.0.0.1"
|
||||
ttl = 60
|
||||
|
||||
[[zones]]
|
||||
domain = "other.local"
|
||||
record_type = "AAAA"
|
||||
value = "::1"
|
||||
ttl = 120
|
||||
```
|
||||
|
||||
All sections are optional — sensible defaults are used if the config file is missing.
|
||||
|
||||
## Request Pipeline
|
||||
|
||||
```
|
||||
Query -> Parse -> Local Zones -> Cache -> Upstream Forward -> Respond
|
||||
```
|
||||
|
||||
1. **Local zones** — match against records defined in `[[zones]]`, respond immediately
|
||||
2. **Cache** — return TTL-adjusted cached response if available
|
||||
3. **Forward** — send query to upstream resolver, cache the response
|
||||
4. **SERVFAIL** — returned to client on upstream failure
|
||||
|
||||
## Caching
|
||||
|
||||
- TTL derived from minimum TTL across answer records
|
||||
- Clamped to configured `min_ttl`/`max_ttl` bounds
|
||||
- TTLs in cached responses decrease over time (adjusted on serve)
|
||||
- Lazy eviction on capacity overflow + periodic sweep every 1000 queries
|
||||
|
||||
## Logging
|
||||
|
||||
Controlled via `RUST_LOG` environment variable:
|
||||
|
||||
```bash
|
||||
RUST_LOG=info sudo cargo run # default — one line per query
|
||||
RUST_LOG=debug sudo cargo run # includes response details
|
||||
RUST_LOG=warn sudo cargo run # errors only
|
||||
```
|
||||
|
||||
Log output:
|
||||
|
||||
```
|
||||
2026-03-10T14:23:01.123Z INFO 192.168.1.5:41234 | A google.com | FORWARD | NOERROR | 12ms
|
||||
2026-03-10T14:23:01.456Z INFO 192.168.1.5:41235 | A mysite.local | LOCAL | NOERROR | 0ms
|
||||
2026-03-10T14:23:02.789Z INFO 192.168.1.5:41236 | A google.com | CACHED | NOERROR | 0ms
|
||||
```
|
||||
|
||||
Stats summary (total, forwarded, cached, local, blocked, errors) logged every 1000 queries.
|
||||
|
||||
## Project Structure
|
||||
|
||||
```
|
||||
src/
|
||||
main.rs # startup, config load, UDP listen loop, request pipeline
|
||||
lib.rs # module declarations, Error/Result type aliases
|
||||
buffer.rs # BytePacketBuffer — 512-byte DNS wire format read/write
|
||||
header.rs # DnsHeader, ResultCode
|
||||
question.rs # DnsQuestion, QueryType
|
||||
record.rs # DnsRecord (A, NS, CNAME, MX, AAAA, UNKNOWN)
|
||||
packet.rs # DnsPacket — full DNS message parse/serialize
|
||||
config.rs # TOML config loading, zone map builder
|
||||
cache.rs # TTL-aware DNS response cache with lazy eviction
|
||||
forward.rs # upstream forwarding, SERVFAIL builder
|
||||
stats.rs # query counters and periodic summary
|
||||
```
|
||||
|
||||
## Dependencies
|
||||
|
||||
```toml
|
||||
toml = "0.8"
|
||||
serde = { version = "1", features = ["derive"] }
|
||||
log = "0.4"
|
||||
env_logger = "0.11"
|
||||
```
|
||||
|
||||
25
dns_fun.toml
Normal file
25
dns_fun.toml
Normal file
@@ -0,0 +1,25 @@
|
||||
[server]
|
||||
bind_addr = "0.0.0.0:53"
|
||||
|
||||
[upstream]
|
||||
address = "8.8.8.8"
|
||||
port = 53
|
||||
timeout_ms = 3000
|
||||
|
||||
[cache]
|
||||
max_entries = 10000
|
||||
min_ttl = 60
|
||||
max_ttl = 86400
|
||||
|
||||
# Example zone records:
|
||||
# [[zones]]
|
||||
# domain = "dimescu.ro"
|
||||
# record_type = "A"
|
||||
# value = "3.120.139.105"
|
||||
# ttl = 30
|
||||
|
||||
# [[zones]]
|
||||
# domain = "test.local"
|
||||
# record_type = "A"
|
||||
# value = "127.0.0.1"
|
||||
# ttl = 60
|
||||
181
src/buffer.rs
Normal file
181
src/buffer.rs
Normal file
@@ -0,0 +1,181 @@
|
||||
use crate::{Result};
|
||||
|
||||
pub struct BytePacketBuffer {
|
||||
pub buf: [u8; 512],
|
||||
pub pos: usize,
|
||||
}
|
||||
|
||||
impl BytePacketBuffer {
|
||||
pub fn new() -> BytePacketBuffer {
|
||||
BytePacketBuffer {
|
||||
buf: [0; 512],
|
||||
pos: 0,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn pos(&self) -> usize {
|
||||
self.pos
|
||||
}
|
||||
|
||||
pub fn filled(&self) -> &[u8] {
|
||||
&self.buf[..self.pos]
|
||||
}
|
||||
|
||||
pub fn step(&mut self, steps: usize) -> Result<()> {
|
||||
self.pos += steps;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn seek(&mut self, pos: usize) -> Result<()> {
|
||||
self.pos = pos;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn read(&mut self) -> Result<u8> {
|
||||
if self.pos >= 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
let res = self.buf[self.pos];
|
||||
self.pos += 1;
|
||||
Ok(res)
|
||||
}
|
||||
|
||||
pub fn get(&self, pos: usize) -> Result<u8> {
|
||||
if pos >= 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
Ok(self.buf[pos])
|
||||
}
|
||||
|
||||
pub fn get_range(&self, start: usize, len: usize) -> Result<&[u8]> {
|
||||
if start + len > 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
Ok(&self.buf[start..start + len])
|
||||
}
|
||||
|
||||
pub fn read_u16(&mut self) -> Result<u16> {
|
||||
let res = ((self.read()? as u16) << 8) | (self.read()? as u16);
|
||||
Ok(res)
|
||||
}
|
||||
|
||||
pub fn read_u32(&mut self) -> Result<u32> {
|
||||
let res = ((self.read()? as u32) << 24)
|
||||
| ((self.read()? as u32) << 16)
|
||||
| ((self.read()? as u32) << 8)
|
||||
| ((self.read()? as u32) << 0);
|
||||
Ok(res)
|
||||
}
|
||||
|
||||
/// Read a qname, handling label compression (pointer jumps).
|
||||
/// Converts wire format like [3]www[6]google[3]com[0] into "www.google.com".
|
||||
pub fn read_qname(&mut self, outstr: &mut String) -> Result<()> {
|
||||
let mut pos = self.pos();
|
||||
let mut jumped = false;
|
||||
let max_jumps = 5;
|
||||
let mut jumps_performed = 0;
|
||||
let mut delim = "";
|
||||
|
||||
loop {
|
||||
if jumps_performed > max_jumps {
|
||||
return Err(format!("Limit of {} jumps exceeded", max_jumps).into());
|
||||
}
|
||||
|
||||
let len = self.get(pos)?;
|
||||
|
||||
if (len & 0xC0) == 0xC0 {
|
||||
if !jumped {
|
||||
self.seek(pos + 2)?;
|
||||
}
|
||||
|
||||
let b2 = self.get(pos + 1)? as u16;
|
||||
let offset = (((len as u16) ^ 0xC0) << 8) | b2;
|
||||
pos = offset as usize;
|
||||
|
||||
jumped = true;
|
||||
jumps_performed += 1;
|
||||
continue;
|
||||
} else {
|
||||
pos += 1;
|
||||
|
||||
if len == 0 {
|
||||
break;
|
||||
}
|
||||
|
||||
outstr.push_str(delim);
|
||||
|
||||
let str_buffer = self.get_range(pos, len as usize)?;
|
||||
for &b in str_buffer {
|
||||
outstr.push(b.to_ascii_lowercase() as char);
|
||||
}
|
||||
|
||||
delim = ".";
|
||||
pos += len as usize;
|
||||
}
|
||||
}
|
||||
|
||||
if !jumped {
|
||||
self.seek(pos)?;
|
||||
}
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn write(&mut self, val: u8) -> Result<()> {
|
||||
if self.pos >= 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
self.buf[self.pos] = val;
|
||||
self.pos += 1;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn write_u8(&mut self, val: u8) -> Result<()> {
|
||||
self.write(val)
|
||||
}
|
||||
|
||||
pub fn write_u16(&mut self, val: u16) -> Result<()> {
|
||||
self.write((val >> 8) as u8)?;
|
||||
self.write((val & 0xFF) as u8)?;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn write_u32(&mut self, val: u32) -> Result<()> {
|
||||
self.write(((val >> 24) & 0xFF) as u8)?;
|
||||
self.write(((val >> 16) & 0xFF) as u8)?;
|
||||
self.write(((val >> 8) & 0xFF) as u8)?;
|
||||
self.write(((val >> 0) & 0xFF) as u8)?;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn write_qname(&mut self, qname: &str) -> Result<()> {
|
||||
for label in qname.split('.') {
|
||||
let len = label.len();
|
||||
if len > 0x3f {
|
||||
return Err("Single label exceeds 63 characters of length".into());
|
||||
}
|
||||
|
||||
self.write_u8(len as u8)?;
|
||||
for b in label.as_bytes() {
|
||||
self.write_u8(*b)?;
|
||||
}
|
||||
}
|
||||
|
||||
self.write_u8(0)?;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn set(&mut self, pos: usize, val: u8) -> Result<()> {
|
||||
if pos >= 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
self.buf[pos] = val;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn set_u16(&mut self, pos: usize, val: u16) -> Result<()> {
|
||||
self.set(pos, (val >> 8) as u8)?;
|
||||
self.set(pos + 1, (val & 0xFF) as u8)?;
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
95
src/cache.rs
Normal file
95
src/cache.rs
Normal file
@@ -0,0 +1,95 @@
|
||||
use std::collections::HashMap;
|
||||
use std::time::{Duration, Instant};
|
||||
|
||||
use crate::packet::DnsPacket;
|
||||
use crate::question::QueryType;
|
||||
use crate::record::DnsRecord;
|
||||
|
||||
struct CacheEntry {
|
||||
packet: DnsPacket,
|
||||
inserted_at: Instant,
|
||||
ttl: Duration,
|
||||
}
|
||||
|
||||
pub struct DnsCache {
|
||||
entries: HashMap<(String, QueryType), CacheEntry>,
|
||||
max_entries: usize,
|
||||
min_ttl: u32,
|
||||
max_ttl: u32,
|
||||
query_count: u64,
|
||||
}
|
||||
|
||||
impl DnsCache {
|
||||
pub fn new(max_entries: usize, min_ttl: u32, max_ttl: u32) -> Self {
|
||||
DnsCache {
|
||||
entries: HashMap::new(),
|
||||
max_entries,
|
||||
min_ttl,
|
||||
max_ttl,
|
||||
query_count: 0,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn lookup(&mut self, domain: &str, qtype: QueryType) -> Option<DnsPacket> {
|
||||
self.query_count += 1;
|
||||
|
||||
// Periodic eviction every 1000 queries
|
||||
if self.query_count % 1000 == 0 {
|
||||
self.evict_expired();
|
||||
}
|
||||
|
||||
let key = (domain.to_string(), qtype);
|
||||
let entry = self.entries.get(&key)?;
|
||||
|
||||
let elapsed = entry.inserted_at.elapsed();
|
||||
if elapsed >= entry.ttl {
|
||||
self.entries.remove(&key);
|
||||
return None;
|
||||
}
|
||||
|
||||
let remaining_secs = (entry.ttl - elapsed).as_secs() as u32;
|
||||
let remaining = remaining_secs.max(1);
|
||||
|
||||
let mut packet = entry.packet.clone();
|
||||
adjust_ttls(&mut packet.answers, remaining);
|
||||
adjust_ttls(&mut packet.authorities, remaining);
|
||||
adjust_ttls(&mut packet.resources, remaining);
|
||||
|
||||
Some(packet)
|
||||
}
|
||||
|
||||
pub fn insert(&mut self, domain: &str, qtype: QueryType, packet: &DnsPacket) {
|
||||
if self.entries.len() >= self.max_entries {
|
||||
self.evict_expired();
|
||||
// If still full after eviction, skip insertion
|
||||
if self.entries.len() >= self.max_entries {
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
let min_ttl = extract_min_ttl(&packet.answers)
|
||||
.unwrap_or(self.min_ttl)
|
||||
.clamp(self.min_ttl, self.max_ttl);
|
||||
|
||||
let key = (domain.to_string(), qtype);
|
||||
self.entries.insert(key, CacheEntry {
|
||||
packet: packet.clone(),
|
||||
inserted_at: Instant::now(),
|
||||
ttl: Duration::from_secs(min_ttl as u64),
|
||||
});
|
||||
}
|
||||
|
||||
fn evict_expired(&mut self) {
|
||||
self.entries.retain(|_, entry| entry.inserted_at.elapsed() < entry.ttl);
|
||||
}
|
||||
}
|
||||
|
||||
fn extract_min_ttl(records: &[DnsRecord]) -> Option<u32> {
|
||||
records.iter().map(|r| r.ttl()).min()
|
||||
}
|
||||
|
||||
fn adjust_ttls(records: &mut [DnsRecord], new_ttl: u32) {
|
||||
for record in records.iter_mut() {
|
||||
record.set_ttl(new_ttl);
|
||||
}
|
||||
}
|
||||
169
src/config.rs
Normal file
169
src/config.rs
Normal file
@@ -0,0 +1,169 @@
|
||||
use std::collections::HashMap;
|
||||
use std::net::Ipv4Addr;
|
||||
use std::net::Ipv6Addr;
|
||||
use std::path::Path;
|
||||
|
||||
use serde::Deserialize;
|
||||
|
||||
use crate::question::QueryType;
|
||||
use crate::record::DnsRecord;
|
||||
use crate::Result;
|
||||
|
||||
#[derive(Deserialize)]
|
||||
pub struct Config {
|
||||
#[serde(default)]
|
||||
pub server: ServerConfig,
|
||||
#[serde(default)]
|
||||
pub upstream: UpstreamConfig,
|
||||
#[serde(default)]
|
||||
pub cache: CacheConfig,
|
||||
#[serde(default)]
|
||||
pub zones: Vec<ZoneRecord>,
|
||||
}
|
||||
|
||||
#[derive(Deserialize)]
|
||||
pub struct ServerConfig {
|
||||
#[serde(default = "default_bind_addr")]
|
||||
pub bind_addr: String,
|
||||
}
|
||||
|
||||
impl Default for ServerConfig {
|
||||
fn default() -> Self {
|
||||
ServerConfig {
|
||||
bind_addr: default_bind_addr(),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn default_bind_addr() -> String {
|
||||
"0.0.0.0:53".to_string()
|
||||
}
|
||||
|
||||
#[derive(Deserialize)]
|
||||
pub struct UpstreamConfig {
|
||||
#[serde(default = "default_upstream_addr")]
|
||||
pub address: String,
|
||||
#[serde(default = "default_upstream_port")]
|
||||
pub port: u16,
|
||||
#[serde(default = "default_timeout_ms")]
|
||||
pub timeout_ms: u64,
|
||||
}
|
||||
|
||||
impl Default for UpstreamConfig {
|
||||
fn default() -> Self {
|
||||
UpstreamConfig {
|
||||
address: default_upstream_addr(),
|
||||
port: default_upstream_port(),
|
||||
timeout_ms: default_timeout_ms(),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn default_upstream_addr() -> String {
|
||||
"8.8.8.8".to_string()
|
||||
}
|
||||
fn default_upstream_port() -> u16 {
|
||||
53
|
||||
}
|
||||
fn default_timeout_ms() -> u64 {
|
||||
3000
|
||||
}
|
||||
|
||||
#[derive(Deserialize)]
|
||||
pub struct CacheConfig {
|
||||
#[serde(default = "default_max_entries")]
|
||||
pub max_entries: usize,
|
||||
#[serde(default = "default_min_ttl")]
|
||||
pub min_ttl: u32,
|
||||
#[serde(default = "default_max_ttl")]
|
||||
pub max_ttl: u32,
|
||||
}
|
||||
|
||||
impl Default for CacheConfig {
|
||||
fn default() -> Self {
|
||||
CacheConfig {
|
||||
max_entries: default_max_entries(),
|
||||
min_ttl: default_min_ttl(),
|
||||
max_ttl: default_max_ttl(),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn default_max_entries() -> usize {
|
||||
10000
|
||||
}
|
||||
fn default_min_ttl() -> u32 {
|
||||
60
|
||||
}
|
||||
fn default_max_ttl() -> u32 {
|
||||
86400
|
||||
}
|
||||
|
||||
#[derive(Deserialize)]
|
||||
pub struct ZoneRecord {
|
||||
pub domain: String,
|
||||
pub record_type: String,
|
||||
pub value: String,
|
||||
#[serde(default = "default_zone_ttl")]
|
||||
pub ttl: u32,
|
||||
}
|
||||
|
||||
fn default_zone_ttl() -> u32 {
|
||||
300
|
||||
}
|
||||
|
||||
pub fn load_config(path: &str) -> Result<Config> {
|
||||
if !Path::new(path).exists() {
|
||||
return Ok(Config {
|
||||
server: ServerConfig::default(),
|
||||
upstream: UpstreamConfig::default(),
|
||||
cache: CacheConfig::default(),
|
||||
zones: Vec::new(),
|
||||
});
|
||||
}
|
||||
let contents = std::fs::read_to_string(path)?;
|
||||
let config: Config = toml::from_str(&contents)?;
|
||||
Ok(config)
|
||||
}
|
||||
|
||||
pub fn build_zone_map(zones: &[ZoneRecord]) -> Result<HashMap<(String, QueryType), Vec<DnsRecord>>> {
|
||||
let mut map: HashMap<(String, QueryType), Vec<DnsRecord>> = HashMap::new();
|
||||
|
||||
for zone in zones {
|
||||
let domain = zone.domain.to_lowercase();
|
||||
let (qtype, record) = match zone.record_type.to_uppercase().as_str() {
|
||||
"A" => {
|
||||
let addr: Ipv4Addr = zone.value.parse()
|
||||
.map_err(|e| format!("invalid A record value '{}': {}", zone.value, e))?;
|
||||
(QueryType::A, DnsRecord::A { domain: domain.clone(), addr, ttl: zone.ttl })
|
||||
}
|
||||
"AAAA" => {
|
||||
let addr: Ipv6Addr = zone.value.parse()
|
||||
.map_err(|e| format!("invalid AAAA record value '{}': {}", zone.value, e))?;
|
||||
(QueryType::AAAA, DnsRecord::AAAA { domain: domain.clone(), addr, ttl: zone.ttl })
|
||||
}
|
||||
"CNAME" => {
|
||||
(QueryType::CNAME, DnsRecord::CNAME { domain: domain.clone(), host: zone.value.clone(), ttl: zone.ttl })
|
||||
}
|
||||
"NS" => {
|
||||
(QueryType::NS, DnsRecord::NS { domain: domain.clone(), host: zone.value.clone(), ttl: zone.ttl })
|
||||
}
|
||||
"MX" => {
|
||||
let parts: Vec<&str> = zone.value.splitn(2, ' ').collect();
|
||||
if parts.len() != 2 {
|
||||
return Err(format!("MX value must be 'priority host', got '{}'", zone.value).into());
|
||||
}
|
||||
let priority: u16 = parts[0].parse()
|
||||
.map_err(|e| format!("invalid MX priority '{}': {}", parts[0], e))?;
|
||||
(QueryType::MX, DnsRecord::MX { domain: domain.clone(), priority, host: parts[1].to_string(), ttl: zone.ttl })
|
||||
}
|
||||
other => {
|
||||
return Err(format!("unsupported record type '{}'", other).into());
|
||||
}
|
||||
};
|
||||
|
||||
map.entry((domain, qtype)).or_default().push(record);
|
||||
}
|
||||
|
||||
Ok(map)
|
||||
}
|
||||
27
src/forward.rs
Normal file
27
src/forward.rs
Normal file
@@ -0,0 +1,27 @@
|
||||
use std::net::SocketAddr;
|
||||
use std::time::Duration;
|
||||
|
||||
use tokio::net::UdpSocket;
|
||||
use tokio::time::timeout;
|
||||
|
||||
use crate::buffer::BytePacketBuffer;
|
||||
use crate::packet::DnsPacket;
|
||||
use crate::Result;
|
||||
|
||||
pub async fn forward_query(
|
||||
query: &DnsPacket,
|
||||
upstream: SocketAddr,
|
||||
timeout_duration: Duration,
|
||||
) -> Result<DnsPacket> {
|
||||
let socket = UdpSocket::bind("0.0.0.0:0").await?;
|
||||
|
||||
let mut send_buffer = BytePacketBuffer::new();
|
||||
query.write(&mut send_buffer)?;
|
||||
|
||||
socket.send_to(send_buffer.filled(), upstream).await?;
|
||||
|
||||
let mut recv_buffer = BytePacketBuffer::new();
|
||||
timeout(timeout_duration, socket.recv_from(&mut recv_buffer.buf)).await??;
|
||||
|
||||
DnsPacket::from_buffer(&mut recv_buffer)
|
||||
}
|
||||
133
src/header.rs
Normal file
133
src/header.rs
Normal file
@@ -0,0 +1,133 @@
|
||||
use crate::buffer::BytePacketBuffer;
|
||||
use crate::Result;
|
||||
|
||||
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
|
||||
pub enum ResultCode {
|
||||
NOERROR = 0,
|
||||
FORMERR = 1,
|
||||
SERVFAIL = 2,
|
||||
NXDOMAIN = 3,
|
||||
NOTIMP = 4,
|
||||
REFUSED = 5,
|
||||
}
|
||||
|
||||
impl ResultCode {
|
||||
pub fn from_num(num: u8) -> ResultCode {
|
||||
match num {
|
||||
1 => ResultCode::FORMERR,
|
||||
2 => ResultCode::SERVFAIL,
|
||||
3 => ResultCode::NXDOMAIN,
|
||||
4 => ResultCode::NOTIMP,
|
||||
5 => ResultCode::REFUSED,
|
||||
0 | _ => ResultCode::NOERROR,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn as_str(&self) -> &'static str {
|
||||
match self {
|
||||
ResultCode::NOERROR => "NOERROR",
|
||||
ResultCode::FORMERR => "FORMERR",
|
||||
ResultCode::SERVFAIL => "SERVFAIL",
|
||||
ResultCode::NXDOMAIN => "NXDOMAIN",
|
||||
ResultCode::NOTIMP => "NOTIMP",
|
||||
ResultCode::REFUSED => "REFUSED",
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Clone, Debug)]
|
||||
pub struct DnsHeader {
|
||||
pub id: u16,
|
||||
|
||||
pub recursion_desired: bool,
|
||||
pub truncated_message: bool,
|
||||
pub authoritative_answer: bool,
|
||||
pub opcode: u8,
|
||||
pub response: bool,
|
||||
|
||||
pub rescode: ResultCode,
|
||||
pub checking_disabled: bool,
|
||||
pub authed_data: bool,
|
||||
pub z: bool,
|
||||
pub recursion_available: bool,
|
||||
|
||||
pub questions: u16,
|
||||
pub answers: u16,
|
||||
pub authoritative_entries: u16,
|
||||
pub resource_entries: u16,
|
||||
}
|
||||
|
||||
impl DnsHeader {
|
||||
pub fn new() -> DnsHeader {
|
||||
DnsHeader {
|
||||
id: 0,
|
||||
recursion_desired: false,
|
||||
truncated_message: false,
|
||||
authoritative_answer: false,
|
||||
opcode: 0,
|
||||
response: false,
|
||||
rescode: ResultCode::NOERROR,
|
||||
checking_disabled: false,
|
||||
authed_data: false,
|
||||
z: false,
|
||||
recursion_available: false,
|
||||
questions: 0,
|
||||
answers: 0,
|
||||
authoritative_entries: 0,
|
||||
resource_entries: 0,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn read(&mut self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
self.id = buffer.read_u16()?;
|
||||
|
||||
let flags = buffer.read_u16()?;
|
||||
let a = (flags >> 8) as u8;
|
||||
let b = (flags & 0xFF) as u8;
|
||||
self.recursion_desired = (a & (1 << 0)) > 0;
|
||||
self.truncated_message = (a & (1 << 1)) > 0;
|
||||
self.authoritative_answer = (a & (1 << 2)) > 0;
|
||||
self.opcode = (a >> 3) & 0x0F;
|
||||
self.response = (a & (1 << 7)) > 0;
|
||||
|
||||
self.rescode = ResultCode::from_num(b & 0x0F);
|
||||
self.checking_disabled = (b & (1 << 4)) > 0;
|
||||
self.authed_data = (b & (1 << 5)) > 0;
|
||||
self.z = (b & (1 << 6)) > 0;
|
||||
self.recursion_available = (b & (1 << 7)) > 0;
|
||||
|
||||
self.questions = buffer.read_u16()?;
|
||||
self.answers = buffer.read_u16()?;
|
||||
self.authoritative_entries = buffer.read_u16()?;
|
||||
self.resource_entries = buffer.read_u16()?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn write(&self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
buffer.write_u16(self.id)?;
|
||||
|
||||
buffer.write_u8(
|
||||
(self.recursion_desired as u8)
|
||||
| ((self.truncated_message as u8) << 1)
|
||||
| ((self.authoritative_answer as u8) << 2)
|
||||
| (self.opcode << 3)
|
||||
| ((self.response as u8) << 7) as u8,
|
||||
)?;
|
||||
|
||||
buffer.write_u8(
|
||||
(self.rescode as u8)
|
||||
| ((self.checking_disabled as u8) << 4)
|
||||
| ((self.authed_data as u8) << 5)
|
||||
| ((self.z as u8) << 6)
|
||||
| ((self.recursion_available as u8) << 7),
|
||||
)?;
|
||||
|
||||
buffer.write_u16(self.questions)?;
|
||||
buffer.write_u16(self.answers)?;
|
||||
buffer.write_u16(self.authoritative_entries)?;
|
||||
buffer.write_u16(self.resource_entries)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
12
src/lib.rs
Normal file
12
src/lib.rs
Normal file
@@ -0,0 +1,12 @@
|
||||
pub mod buffer;
|
||||
pub mod cache;
|
||||
pub mod config;
|
||||
pub mod forward;
|
||||
pub mod header;
|
||||
pub mod packet;
|
||||
pub mod question;
|
||||
pub mod record;
|
||||
pub mod stats;
|
||||
|
||||
pub type Error = Box<dyn std::error::Error + Send + Sync>;
|
||||
pub type Result<T> = std::result::Result<T, Error>;
|
||||
917
src/main.rs
917
src/main.rs
@@ -1,801 +1,144 @@
|
||||
use std::fs::File;
|
||||
use std::io::Read;
|
||||
use std::net::Ipv4Addr;
|
||||
use std::net::Ipv6Addr;
|
||||
use std::collections::HashMap;
|
||||
use std::net::SocketAddr;
|
||||
use std::sync::{Arc, Mutex};
|
||||
use std::time::{Duration, Instant};
|
||||
|
||||
type Error = Box<dyn std::error::Error>;
|
||||
type Result<T> = std::result::Result<T, Error>;
|
||||
use log::{debug, error, info, warn};
|
||||
use tokio::net::UdpSocket;
|
||||
|
||||
pub struct BytePacketBuffer {
|
||||
pub buf: [u8; 512],
|
||||
pub pos: usize,
|
||||
use dns_fun::buffer::BytePacketBuffer;
|
||||
use dns_fun::cache::DnsCache;
|
||||
use dns_fun::config::{build_zone_map, load_config};
|
||||
use dns_fun::forward::forward_query;
|
||||
use dns_fun::header::ResultCode;
|
||||
use dns_fun::packet::DnsPacket;
|
||||
use dns_fun::question::QueryType;
|
||||
use dns_fun::record::DnsRecord;
|
||||
use dns_fun::stats::{QueryPath, ServerStats};
|
||||
|
||||
struct ServerCtx {
|
||||
socket: Arc<UdpSocket>,
|
||||
zone_map: HashMap<(String, QueryType), Vec<DnsRecord>>,
|
||||
cache: Mutex<DnsCache>,
|
||||
stats: Mutex<ServerStats>,
|
||||
upstream: SocketAddr,
|
||||
timeout: Duration,
|
||||
}
|
||||
|
||||
impl BytePacketBuffer {
|
||||
#[tokio::main]
|
||||
async fn main() -> dns_fun::Result<()> {
|
||||
env_logger::Builder::from_env(env_logger::Env::default().default_filter_or("info"))
|
||||
.format_timestamp_millis()
|
||||
.init();
|
||||
|
||||
let config_path = std::env::args().nth(1).unwrap_or_else(|| "dns_fun.toml".to_string());
|
||||
let config = load_config(&config_path)?;
|
||||
|
||||
let upstream: SocketAddr = format!("{}:{}", config.upstream.address, config.upstream.port).parse()?;
|
||||
let socket = Arc::new(UdpSocket::bind(&config.server.bind_addr).await?);
|
||||
|
||||
let ctx = Arc::new(ServerCtx {
|
||||
socket: Arc::clone(&socket),
|
||||
zone_map: build_zone_map(&config.zones)?,
|
||||
cache: Mutex::new(DnsCache::new(
|
||||
config.cache.max_entries,
|
||||
config.cache.min_ttl,
|
||||
config.cache.max_ttl,
|
||||
)),
|
||||
stats: Mutex::new(ServerStats::new()),
|
||||
upstream,
|
||||
timeout: Duration::from_millis(config.upstream.timeout_ms),
|
||||
});
|
||||
|
||||
info!(
|
||||
"dns_fun starting on {}, upstream {}, {} zone records, cache max {}",
|
||||
config.server.bind_addr,
|
||||
upstream,
|
||||
ctx.zone_map.len(),
|
||||
config.cache.max_entries,
|
||||
);
|
||||
|
||||
/// This gives us a fresh buffer for holding the packet contents, and a
|
||||
/// field for keeping track of where we are.
|
||||
pub fn new() -> BytePacketBuffer {
|
||||
BytePacketBuffer {
|
||||
buf: [0; 512],
|
||||
pos: 0,
|
||||
}
|
||||
}
|
||||
|
||||
/// Current position within buffer
|
||||
fn pos(&self) -> usize {
|
||||
self.pos
|
||||
}
|
||||
|
||||
/// Step the buffer position forward a specific number of steps
|
||||
fn step(&mut self, steps: usize) -> Result<()> {
|
||||
self.pos += steps;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
/// Change the buffer position
|
||||
fn seek(&mut self, pos: usize) -> Result<()> {
|
||||
self.pos = pos;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
/// Read a single byte and move the position one step forward
|
||||
fn read(&mut self) -> Result<u8> {
|
||||
if self.pos >= 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
let res = self.buf[self.pos];
|
||||
self.pos += 1;
|
||||
|
||||
Ok(res)
|
||||
}
|
||||
|
||||
/// Get a single byte, without changing the buffer position
|
||||
fn get(&mut self, pos: usize) -> Result<u8> {
|
||||
if pos >= 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
Ok(self.buf[pos])
|
||||
}
|
||||
|
||||
/// Get a range of bytes
|
||||
fn get_range(&mut self, start: usize, len: usize) -> Result<&[u8]> {
|
||||
if start + len >= 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
Ok(&self.buf[start..start + len as usize])
|
||||
}
|
||||
|
||||
/// Read two bytes, stepping two steps forward
|
||||
fn read_u16(&mut self) -> Result<u16> {
|
||||
let res = ((self.read()? as u16) << 8) | (self.read()? as u16);
|
||||
|
||||
Ok(res)
|
||||
}
|
||||
|
||||
/// Read four bytes, stepping four steps forward
|
||||
fn read_u32(&mut self) -> Result<u32> {
|
||||
let res = ((self.read()? as u32) << 24)
|
||||
| ((self.read()? as u32) << 16)
|
||||
| ((self.read()? as u32) << 8)
|
||||
| ((self.read()? as u32) << 0);
|
||||
|
||||
Ok(res)
|
||||
}
|
||||
|
||||
|
||||
/// Read a qname
|
||||
///
|
||||
/// The tricky part: Reading domain names, taking labels into consideration.
|
||||
/// Will take something like [3]www[6]google[3]com[0] and append
|
||||
/// www.google.com to outstr.
|
||||
fn read_qname(&mut self, outstr: &mut String) -> Result<()> {
|
||||
// Since we might encounter jumps, we'll keep track of our position
|
||||
// locally as opposed to using the position within the struct. This
|
||||
// allows us to move the shared position to a point past our current
|
||||
// qname, while keeping track of our progress on the current qname
|
||||
// using this variable.
|
||||
let mut pos = self.pos();
|
||||
|
||||
// track whether or not we've jumped
|
||||
let mut jumped = false;
|
||||
let max_jumps = 5;
|
||||
let mut jumps_performed = 0;
|
||||
|
||||
// Our delimiter which we append for each label. Since we don't want a
|
||||
// dot at the beginning of the domain name we'll leave it empty for now
|
||||
// and set it to "." at the end of the first iteration.
|
||||
let mut delim = "";
|
||||
loop {
|
||||
// Dns Packets are untrusted data, so we need to be paranoid. Someone
|
||||
// can craft a packet with a cycle in the jump instructions. This guards
|
||||
// against such packets.
|
||||
if jumps_performed > max_jumps {
|
||||
return Err(format!("Limit of {} jumps exceeded", max_jumps).into());
|
||||
}
|
||||
|
||||
// At this point, we're always at the beginning of a label. Recall
|
||||
// that labels start with a length byte.
|
||||
let len = self.get(pos)?;
|
||||
|
||||
// If len has the two most significant bit are set, it represents a
|
||||
// jump to some other offset in the packet:
|
||||
if (len & 0xC0) == 0xC0 {
|
||||
// Update the buffer position to a point past the current
|
||||
// label. We don't need to touch it any further.
|
||||
if !jumped {
|
||||
self.seek(pos + 2)?;
|
||||
}
|
||||
|
||||
// Read another byte, calculate offset and perform the jump by
|
||||
// updating our local position variable
|
||||
let b2 = self.get(pos + 1)? as u16;
|
||||
let offset = (((len as u16) ^ 0xC0) << 8) | b2;
|
||||
pos = offset as usize;
|
||||
|
||||
// Indicate that a jump was performed.
|
||||
jumped = true;
|
||||
jumps_performed += 1;
|
||||
|
||||
continue;
|
||||
}
|
||||
// The base scenario, where we're reading a single label and
|
||||
// appending it to the output:
|
||||
else {
|
||||
// Move a single byte forward to move past the length byte.
|
||||
pos += 1;
|
||||
|
||||
// Domain names are terminated by an empty label of length 0,
|
||||
// so if the length is zero we're done.
|
||||
if len == 0 {
|
||||
break;
|
||||
}
|
||||
|
||||
// Append the delimiter to our output buffer first.
|
||||
outstr.push_str(delim);
|
||||
|
||||
// Extract the actual ASCII bytes for this label and append them
|
||||
// to the output buffer.
|
||||
let str_buffer = self.get_range(pos, len as usize)?;
|
||||
outstr.push_str(&String::from_utf8_lossy(str_buffer).to_lowercase());
|
||||
|
||||
delim = ".";
|
||||
|
||||
// Move forward the full length of the label.
|
||||
pos += len as usize;
|
||||
}
|
||||
}
|
||||
|
||||
if !jumped {
|
||||
self.seek(pos)?;
|
||||
}
|
||||
|
||||
Ok(())
|
||||
}
|
||||
fn write(&mut self, val: u8) -> Result<()> {
|
||||
if self.pos >= 512 {
|
||||
return Err("End of buffer".into());
|
||||
}
|
||||
self.buf[self.pos] = val;
|
||||
self.pos += 1;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
fn write_u8(&mut self, val: u8) -> Result<()> {
|
||||
self.write(val)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
fn write_u16(&mut self, val: u16) -> Result<()> {
|
||||
self.write((val >> 8) as u8)?;
|
||||
self.write((val & 0xFF) as u8)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
fn write_u32(&mut self, val: u32) -> Result<()> {
|
||||
self.write(((val >> 24) & 0xFF) as u8)?;
|
||||
self.write(((val >> 16) & 0xFF) as u8)?;
|
||||
self.write(((val >> 8) & 0xFF) as u8)?;
|
||||
self.write(((val >> 0) & 0xFF) as u8)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
fn write_qname(&mut self, qname: &str) -> Result<()> {
|
||||
for label in qname.split('.') {
|
||||
let len = label.len();
|
||||
if len > 0x3f {
|
||||
return Err("Single label exceeds 63 characters of length".into());
|
||||
}
|
||||
|
||||
self.write_u8(len as u8)?;
|
||||
for b in label.as_bytes() {
|
||||
self.write_u8(*b)?;
|
||||
}
|
||||
}
|
||||
|
||||
self.write_u8(0)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
fn set(&mut self, pos: usize, val: u8) -> Result<()> {
|
||||
self.buf[pos] = val;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
fn set_u16(&mut self, pos: usize, val: u16) -> Result<()> {
|
||||
self.set(pos, (val >> 8) as u8)?;
|
||||
self.set(pos + 1, (val & 0xFF) as u8)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
|
||||
pub enum ResultCode {
|
||||
NOERROR = 0,
|
||||
FORMERR = 1,
|
||||
SERVFAIL = 2,
|
||||
NXDOMAIN = 3,
|
||||
NOTIMP = 4,
|
||||
REFUSED = 5,
|
||||
}
|
||||
|
||||
impl ResultCode {
|
||||
pub fn from_num(num: u8) -> ResultCode {
|
||||
match num {
|
||||
1 => ResultCode::FORMERR,
|
||||
2 => ResultCode::SERVFAIL,
|
||||
3 => ResultCode::NXDOMAIN,
|
||||
4 => ResultCode::NOTIMP,
|
||||
5 => ResultCode::REFUSED,
|
||||
0 | _ => ResultCode::NOERROR,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Clone, Debug)]
|
||||
pub struct DnsHeader {
|
||||
pub id: u16, // 16 bits
|
||||
|
||||
pub recursion_desired: bool, // 1 bit
|
||||
pub truncated_message: bool, // 1 bit
|
||||
pub authoritative_answer: bool, // 1 bit
|
||||
pub opcode: u8, // 4 bits
|
||||
pub response: bool, // 1 bit
|
||||
|
||||
pub rescode: ResultCode, // 4 bits
|
||||
pub checking_disabled: bool, // 1 bit
|
||||
pub authed_data: bool, // 1 bit
|
||||
pub z: bool, // 1 bit
|
||||
pub recursion_available: bool, // 1 bit
|
||||
|
||||
pub questions: u16, // 16 bits
|
||||
pub answers: u16, // 16 bits
|
||||
pub authoritative_entries: u16, // 16 bits
|
||||
pub resource_entries: u16, // 16 bits
|
||||
}
|
||||
|
||||
impl DnsHeader {
|
||||
pub fn new() -> DnsHeader {
|
||||
DnsHeader {
|
||||
id: 0,
|
||||
|
||||
recursion_desired: false,
|
||||
truncated_message: false,
|
||||
authoritative_answer: false,
|
||||
opcode: 0,
|
||||
response: false,
|
||||
|
||||
rescode: ResultCode::NOERROR,
|
||||
checking_disabled: false,
|
||||
authed_data: false,
|
||||
z: false,
|
||||
recursion_available: false,
|
||||
|
||||
questions: 0,
|
||||
answers: 0,
|
||||
authoritative_entries: 0,
|
||||
resource_entries: 0,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn read(&mut self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
self.id = buffer.read_u16()?;
|
||||
|
||||
let flags = buffer.read_u16()?;
|
||||
let a = (flags >> 8) as u8;
|
||||
let b = (flags & 0xFF) as u8;
|
||||
self.recursion_desired = (a & (1 << 0)) > 0;
|
||||
self.truncated_message = (a & (1 << 1)) > 0;
|
||||
self.authoritative_answer = (a & (1 << 2)) > 0;
|
||||
self.opcode = (a >> 3) & 0x0F;
|
||||
self.response = (a & (1 << 7)) > 0;
|
||||
|
||||
self.rescode = ResultCode::from_num(b & 0x0F);
|
||||
self.checking_disabled = (b & (1 << 4)) > 0;
|
||||
self.authed_data = (b & (1 << 5)) > 0;
|
||||
self.z = (b & (1 << 6)) > 0;
|
||||
self.recursion_available = (b & (1 << 7)) > 0;
|
||||
|
||||
self.questions = buffer.read_u16()?;
|
||||
self.answers = buffer.read_u16()?;
|
||||
self.authoritative_entries = buffer.read_u16()?;
|
||||
self.resource_entries = buffer.read_u16()?;
|
||||
|
||||
// Return the constant header size
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn write(&self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
buffer.write_u16(self.id)?;
|
||||
|
||||
buffer.write_u8(
|
||||
(self.recursion_desired as u8)
|
||||
| ((self.truncated_message as u8) << 1)
|
||||
| ((self.authoritative_answer as u8) << 2)
|
||||
| (self.opcode << 3)
|
||||
| ((self.response as u8) << 7) as u8,
|
||||
)?;
|
||||
|
||||
buffer.write_u8(
|
||||
(self.rescode as u8)
|
||||
| ((self.checking_disabled as u8) << 4)
|
||||
| ((self.authed_data as u8) << 5)
|
||||
| ((self.z as u8) << 6)
|
||||
| ((self.recursion_available as u8) << 7),
|
||||
)?;
|
||||
|
||||
buffer.write_u16(self.questions)?;
|
||||
buffer.write_u16(self.answers)?;
|
||||
buffer.write_u16(self.authoritative_entries)?;
|
||||
buffer.write_u16(self.resource_entries)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(PartialEq, Eq, Debug, Clone, Hash, Copy)]
|
||||
pub enum QueryType {
|
||||
UNKNOWN(u16),
|
||||
A, // 1
|
||||
NS, // 2
|
||||
CNAME, // 5
|
||||
MX, // 15
|
||||
AAAA, // 28
|
||||
}
|
||||
|
||||
impl QueryType {
|
||||
pub fn to_num(&self) -> u16 {
|
||||
match *self {
|
||||
QueryType::UNKNOWN(x) => x,
|
||||
QueryType::A => 1,
|
||||
QueryType::NS => 2,
|
||||
QueryType::CNAME => 5,
|
||||
QueryType::MX => 15,
|
||||
QueryType::AAAA => 28,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn from_num(num: u16) -> QueryType {
|
||||
match num {
|
||||
1 => QueryType::A,
|
||||
2 => QueryType::NS,
|
||||
5 => QueryType::CNAME,
|
||||
15 => QueryType::MX,
|
||||
28 => QueryType::AAAA,
|
||||
_ => QueryType::UNKNOWN(num),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Debug, Clone, PartialEq, Eq)]
|
||||
pub struct DnsQuestion {
|
||||
pub name: String,
|
||||
pub qtype: QueryType,
|
||||
}
|
||||
|
||||
impl DnsQuestion {
|
||||
pub fn new(name: String, qtype: QueryType) -> DnsQuestion {
|
||||
DnsQuestion {
|
||||
name: name,
|
||||
qtype: qtype,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn read(&mut self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
buffer.read_qname(&mut self.name)?;
|
||||
self.qtype = QueryType::from_num(buffer.read_u16()?); // qtype
|
||||
let _ = buffer.read_u16()?; // class
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn write(&self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
buffer.write_qname(&self.name)?;
|
||||
|
||||
let typenum = self.qtype.to_num();
|
||||
buffer.write_u16(typenum)?;
|
||||
buffer.write_u16(1)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
|
||||
#[allow(dead_code)]
|
||||
pub enum DnsRecord {
|
||||
UNKNOWN {
|
||||
domain: String,
|
||||
qtype: u16,
|
||||
data_len: u16,
|
||||
ttl: u32,
|
||||
}, // 0
|
||||
A {
|
||||
domain: String,
|
||||
addr: Ipv4Addr,
|
||||
ttl: u32,
|
||||
}, // 1
|
||||
NS {
|
||||
domain: String,
|
||||
host: String,
|
||||
ttl: u32,
|
||||
}, // 2
|
||||
CNAME {
|
||||
domain: String,
|
||||
host: String,
|
||||
ttl: u32,
|
||||
}, // 5
|
||||
MX {
|
||||
domain: String,
|
||||
priority: u16,
|
||||
host: String,
|
||||
ttl: u32,
|
||||
}, // 15
|
||||
AAAA {
|
||||
domain: String,
|
||||
addr: Ipv6Addr,
|
||||
ttl: u32,
|
||||
}, // 28
|
||||
}
|
||||
|
||||
impl DnsRecord {
|
||||
pub fn read(buffer: &mut BytePacketBuffer) -> Result<DnsRecord> {
|
||||
let mut domain = String::new();
|
||||
buffer.read_qname(&mut domain)?;
|
||||
|
||||
let qtype_num = buffer.read_u16()?;
|
||||
let qtype = QueryType::from_num(qtype_num);
|
||||
let _ = buffer.read_u16()?;
|
||||
let ttl = buffer.read_u32()?;
|
||||
let data_len = buffer.read_u16()?;
|
||||
|
||||
match qtype {
|
||||
QueryType::A => {
|
||||
let raw_addr = buffer.read_u32()?;
|
||||
let addr = Ipv4Addr::new(
|
||||
((raw_addr >> 24) & 0xFF) as u8,
|
||||
((raw_addr >> 16) & 0xFF) as u8,
|
||||
((raw_addr >> 8) & 0xFF) as u8,
|
||||
((raw_addr >> 0) & 0xFF) as u8,
|
||||
);
|
||||
|
||||
Ok(DnsRecord::A {
|
||||
domain: domain,
|
||||
addr: addr,
|
||||
ttl: ttl,
|
||||
})
|
||||
}
|
||||
QueryType::AAAA => {
|
||||
let raw_addr1 = buffer.read_u32()?;
|
||||
let raw_addr2 = buffer.read_u32()?;
|
||||
let raw_addr3 = buffer.read_u32()?;
|
||||
let raw_addr4 = buffer.read_u32()?;
|
||||
let addr = Ipv6Addr::new(
|
||||
((raw_addr1 >> 16) & 0xFFFF) as u16,
|
||||
((raw_addr1 >> 0) & 0xFFFF) as u16,
|
||||
((raw_addr2 >> 16) & 0xFFFF) as u16,
|
||||
((raw_addr2 >> 0) & 0xFFFF) as u16,
|
||||
((raw_addr3 >> 16) & 0xFFFF) as u16,
|
||||
((raw_addr3 >> 0) & 0xFFFF) as u16,
|
||||
((raw_addr4 >> 16) & 0xFFFF) as u16,
|
||||
((raw_addr4 >> 0) & 0xFFFF) as u16,
|
||||
);
|
||||
|
||||
Ok(DnsRecord::AAAA {
|
||||
domain: domain,
|
||||
addr: addr,
|
||||
ttl: ttl,
|
||||
})
|
||||
}
|
||||
QueryType::NS => {
|
||||
let mut ns = String::new();
|
||||
buffer.read_qname(&mut ns)?;
|
||||
|
||||
Ok(DnsRecord::NS {
|
||||
domain: domain,
|
||||
host: ns,
|
||||
ttl: ttl,
|
||||
})
|
||||
}
|
||||
QueryType::CNAME => {
|
||||
let mut cname = String::new();
|
||||
buffer.read_qname(&mut cname)?;
|
||||
|
||||
Ok(DnsRecord::CNAME {
|
||||
domain: domain,
|
||||
host: cname,
|
||||
ttl: ttl,
|
||||
})
|
||||
}
|
||||
QueryType::MX => {
|
||||
let priority = buffer.read_u16()?;
|
||||
let mut mx = String::new();
|
||||
buffer.read_qname(&mut mx)?;
|
||||
|
||||
Ok(DnsRecord::MX {
|
||||
domain: domain,
|
||||
priority: priority,
|
||||
host: mx,
|
||||
ttl: ttl,
|
||||
})
|
||||
}
|
||||
QueryType::UNKNOWN(_) => {
|
||||
buffer.step(data_len as usize)?;
|
||||
|
||||
Ok(DnsRecord::UNKNOWN {
|
||||
domain: domain,
|
||||
qtype: qtype_num,
|
||||
data_len: data_len,
|
||||
ttl: ttl,
|
||||
})
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pub fn write(&self, buffer: &mut BytePacketBuffer) -> Result<usize> {
|
||||
let start_pos = buffer.pos();
|
||||
|
||||
match *self {
|
||||
DnsRecord::A {
|
||||
ref domain,
|
||||
ref addr,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::A.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
buffer.write_u16(4)?;
|
||||
|
||||
let octets = addr.octets();
|
||||
buffer.write_u8(octets[0])?;
|
||||
buffer.write_u8(octets[1])?;
|
||||
buffer.write_u8(octets[2])?;
|
||||
buffer.write_u8(octets[3])?;
|
||||
}
|
||||
DnsRecord::NS {
|
||||
ref domain,
|
||||
ref host,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::NS.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
|
||||
let pos = buffer.pos();
|
||||
buffer.write_u16(0)?;
|
||||
|
||||
buffer.write_qname(host)?;
|
||||
|
||||
let size = buffer.pos() - (pos + 2);
|
||||
buffer.set_u16(pos, size as u16)?;
|
||||
}
|
||||
DnsRecord::CNAME {
|
||||
ref domain,
|
||||
ref host,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::CNAME.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
|
||||
let pos = buffer.pos();
|
||||
buffer.write_u16(0)?;
|
||||
|
||||
buffer.write_qname(host)?;
|
||||
|
||||
let size = buffer.pos() - (pos + 2);
|
||||
buffer.set_u16(pos, size as u16)?;
|
||||
}
|
||||
DnsRecord::MX {
|
||||
ref domain,
|
||||
priority,
|
||||
ref host,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::MX.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
|
||||
let pos = buffer.pos();
|
||||
buffer.write_u16(0)?;
|
||||
|
||||
buffer.write_u16(priority)?;
|
||||
buffer.write_qname(host)?;
|
||||
|
||||
let size = buffer.pos() - (pos + 2);
|
||||
buffer.set_u16(pos, size as u16)?;
|
||||
}
|
||||
DnsRecord::AAAA {
|
||||
ref domain,
|
||||
ref addr,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::AAAA.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
buffer.write_u16(16)?;
|
||||
|
||||
for octet in &addr.segments() {
|
||||
buffer.write_u16(*octet)?;
|
||||
}
|
||||
}
|
||||
DnsRecord::UNKNOWN { .. } => {
|
||||
println!("Skipping record: {:?}", self);
|
||||
}
|
||||
}
|
||||
|
||||
Ok(buffer.pos() - start_pos)
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Clone, Debug)]
|
||||
pub struct DnsPacket {
|
||||
pub header: DnsHeader,
|
||||
pub questions: Vec<DnsQuestion>,
|
||||
pub answers: Vec<DnsRecord>,
|
||||
pub authorities: Vec<DnsRecord>,
|
||||
pub resources: Vec<DnsRecord>,
|
||||
}
|
||||
|
||||
impl DnsPacket {
|
||||
pub fn new() -> DnsPacket {
|
||||
DnsPacket {
|
||||
header: DnsHeader::new(),
|
||||
questions: Vec::new(),
|
||||
answers: Vec::new(),
|
||||
authorities: Vec::new(),
|
||||
resources: Vec::new(),
|
||||
}
|
||||
}
|
||||
|
||||
pub fn from_buffer(buffer: &mut BytePacketBuffer) -> Result<DnsPacket> {
|
||||
let mut result = DnsPacket::new();
|
||||
result.header.read(buffer)?;
|
||||
|
||||
for _ in 0..result.header.questions {
|
||||
let mut question = DnsQuestion::new("".to_string(), QueryType::UNKNOWN(0));
|
||||
question.read(buffer)?;
|
||||
result.questions.push(question);
|
||||
}
|
||||
|
||||
for _ in 0..result.header.answers {
|
||||
let rec = DnsRecord::read(buffer)?;
|
||||
result.answers.push(rec);
|
||||
}
|
||||
for _ in 0..result.header.authoritative_entries {
|
||||
let rec = DnsRecord::read(buffer)?;
|
||||
result.authorities.push(rec);
|
||||
}
|
||||
for _ in 0..result.header.resource_entries {
|
||||
let rec = DnsRecord::read(buffer)?;
|
||||
result.resources.push(rec);
|
||||
}
|
||||
|
||||
Ok(result)
|
||||
}
|
||||
|
||||
pub fn write(&mut self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
self.header.questions = self.questions.len() as u16;
|
||||
self.header.answers = self.answers.len() as u16;
|
||||
self.header.authoritative_entries = self.authorities.len() as u16;
|
||||
self.header.resource_entries = self.resources.len() as u16;
|
||||
|
||||
self.header.write(buffer)?;
|
||||
|
||||
for question in &self.questions {
|
||||
question.write(buffer)?;
|
||||
}
|
||||
for rec in &self.answers {
|
||||
rec.write(buffer)?;
|
||||
}
|
||||
for rec in &self.authorities {
|
||||
rec.write(buffer)?;
|
||||
}
|
||||
for rec in &self.resources {
|
||||
rec.write(buffer)?;
|
||||
}
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn display(&self) {
|
||||
println!("{:#?}", self.header);
|
||||
|
||||
for q in &self.questions {
|
||||
println!("{:#?}", q);
|
||||
}
|
||||
for rec in &self.answers {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
for rec in &self.authorities {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
for rec in &self.resources {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/*fn main() -> Result<()> {
|
||||
let mut f = File::open("response_packet.txt")?;
|
||||
let mut buffer = BytePacketBuffer::new();
|
||||
f.read(&mut buffer.buf)?;
|
||||
|
||||
let packet = DnsPacket::from_buffer(&mut buffer)?;
|
||||
println!("{:#?}", packet.header);
|
||||
|
||||
for q in packet.questions {
|
||||
println!("{:#?}", q);
|
||||
}
|
||||
for rec in packet.answers {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
for rec in packet.authorities {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
for rec in packet.resources {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
|
||||
Ok(())
|
||||
}*/
|
||||
|
||||
use std::net::UdpSocket;
|
||||
|
||||
fn main() -> std::io::Result<()> {
|
||||
let socket = UdpSocket::bind("0.0.0.0:53")?;
|
||||
loop {
|
||||
let mut buffer = BytePacketBuffer::new();
|
||||
let (number_of_bytes, src_addr) = socket.recv_from(&mut buffer.buf)?;
|
||||
print!("received: {} from {} \n", number_of_bytes, src_addr);
|
||||
let (_, src_addr) = socket.recv_from(&mut buffer.buf).await?;
|
||||
|
||||
let packet = DnsPacket::from_buffer(&mut buffer).unwrap();
|
||||
packet.display();
|
||||
let ctx = Arc::clone(&ctx);
|
||||
tokio::spawn(async move {
|
||||
if let Err(e) = handle_query(buffer, src_addr, &ctx).await {
|
||||
error!("{} | HANDLER ERROR | {}", src_addr, e);
|
||||
}
|
||||
});
|
||||
}
|
||||
}
|
||||
|
||||
let mut resp = DnsPacket::new();
|
||||
resp.header.id = packet.header.id;
|
||||
resp.header.authoritative_answer = true;
|
||||
resp.header.response = true;
|
||||
resp.questions = packet.questions;
|
||||
resp.answers.push(DnsRecord::A{domain: "dimescu.ro".to_string(), addr: Ipv4Addr::new(3, 120, 139, 105), ttl: 30});
|
||||
resp.display();
|
||||
async fn handle_query(
|
||||
mut buffer: BytePacketBuffer,
|
||||
src_addr: SocketAddr,
|
||||
ctx: &ServerCtx,
|
||||
) -> dns_fun::Result<()> {
|
||||
let start = Instant::now();
|
||||
|
||||
let mut req_buffer = BytePacketBuffer::new();
|
||||
resp.write(&mut req_buffer).unwrap();
|
||||
let query = match DnsPacket::from_buffer(&mut buffer) {
|
||||
Ok(packet) => packet,
|
||||
Err(e) => {
|
||||
warn!("{} | PARSE ERROR | {}", src_addr, e);
|
||||
return Ok(());
|
||||
}
|
||||
};
|
||||
|
||||
socket.send_to(&req_buffer.buf[0..req_buffer.pos], src_addr).unwrap();
|
||||
let (qname, qtype) = match query.questions.first() {
|
||||
Some(q) => (q.name.clone(), q.qtype),
|
||||
None => return Ok(()),
|
||||
};
|
||||
|
||||
// Pipeline: local zones -> cache -> upstream
|
||||
// Each lock is scoped to avoid holding MutexGuard across await points.
|
||||
let (response, path) = if let Some(records) = ctx.zone_map.get(&(qname.to_lowercase(), qtype)) {
|
||||
let mut resp = DnsPacket::response_from(&query, ResultCode::NOERROR);
|
||||
resp.answers = records.clone();
|
||||
(resp, QueryPath::Local)
|
||||
} else {
|
||||
let cached = ctx.cache.lock().unwrap().lookup(&qname, qtype);
|
||||
if let Some(cached) = cached {
|
||||
let mut resp = cached;
|
||||
resp.header.id = query.header.id;
|
||||
(resp, QueryPath::Cached)
|
||||
} else {
|
||||
match forward_query(&query, ctx.upstream, ctx.timeout).await {
|
||||
Ok(resp) => {
|
||||
ctx.cache.lock().unwrap().insert(&qname, qtype, &resp);
|
||||
(resp, QueryPath::Forwarded)
|
||||
}
|
||||
Err(e) => {
|
||||
error!("{} | {:?} {} | UPSTREAM ERROR | {}", src_addr, qtype, qname, e);
|
||||
(DnsPacket::response_from(&query, ResultCode::SERVFAIL), QueryPath::UpstreamError)
|
||||
}
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
let elapsed = start.elapsed();
|
||||
|
||||
info!(
|
||||
"{} | {:?} {} | {} | {} | {}ms",
|
||||
src_addr, qtype, qname, path.as_str(),
|
||||
response.header.rescode.as_str(), elapsed.as_millis(),
|
||||
);
|
||||
|
||||
debug!(
|
||||
"response: {} answers, {} authorities, {} resources",
|
||||
response.answers.len(), response.authorities.len(), response.resources.len(),
|
||||
);
|
||||
|
||||
let mut resp_buffer = BytePacketBuffer::new();
|
||||
response.write(&mut resp_buffer)?;
|
||||
ctx.socket.send_to(resp_buffer.filled(), src_addr).await?;
|
||||
|
||||
// Record stats and log summary every 1000 queries (single lock acquisition)
|
||||
let mut s = ctx.stats.lock().unwrap();
|
||||
let total = s.record(path);
|
||||
if total % 1000 == 0 {
|
||||
s.log_summary();
|
||||
}
|
||||
|
||||
Ok(())
|
||||
|
||||
105
src/packet.rs
Normal file
105
src/packet.rs
Normal file
@@ -0,0 +1,105 @@
|
||||
use crate::buffer::BytePacketBuffer;
|
||||
use crate::header::DnsHeader;
|
||||
use crate::question::{DnsQuestion, QueryType};
|
||||
use crate::record::DnsRecord;
|
||||
use crate::Result;
|
||||
|
||||
#[derive(Clone, Debug)]
|
||||
pub struct DnsPacket {
|
||||
pub header: DnsHeader,
|
||||
pub questions: Vec<DnsQuestion>,
|
||||
pub answers: Vec<DnsRecord>,
|
||||
pub authorities: Vec<DnsRecord>,
|
||||
pub resources: Vec<DnsRecord>,
|
||||
}
|
||||
|
||||
impl DnsPacket {
|
||||
pub fn new() -> DnsPacket {
|
||||
DnsPacket {
|
||||
header: DnsHeader::new(),
|
||||
questions: Vec::new(),
|
||||
answers: Vec::new(),
|
||||
authorities: Vec::new(),
|
||||
resources: Vec::new(),
|
||||
}
|
||||
}
|
||||
|
||||
pub fn response_from(query: &DnsPacket, rescode: crate::header::ResultCode) -> DnsPacket {
|
||||
let mut resp = DnsPacket::new();
|
||||
resp.header.id = query.header.id;
|
||||
resp.header.response = true;
|
||||
resp.header.recursion_desired = query.header.recursion_desired;
|
||||
resp.header.recursion_available = true;
|
||||
resp.header.rescode = rescode;
|
||||
resp.questions = query.questions.clone();
|
||||
resp
|
||||
}
|
||||
|
||||
pub fn from_buffer(buffer: &mut BytePacketBuffer) -> Result<DnsPacket> {
|
||||
let mut result = DnsPacket::new();
|
||||
result.header.read(buffer)?;
|
||||
|
||||
for _ in 0..result.header.questions {
|
||||
let mut question = DnsQuestion::new("".to_string(), QueryType::UNKNOWN(0));
|
||||
question.read(buffer)?;
|
||||
result.questions.push(question);
|
||||
}
|
||||
|
||||
for _ in 0..result.header.answers {
|
||||
let rec = DnsRecord::read(buffer)?;
|
||||
result.answers.push(rec);
|
||||
}
|
||||
for _ in 0..result.header.authoritative_entries {
|
||||
let rec = DnsRecord::read(buffer)?;
|
||||
result.authorities.push(rec);
|
||||
}
|
||||
for _ in 0..result.header.resource_entries {
|
||||
let rec = DnsRecord::read(buffer)?;
|
||||
result.resources.push(rec);
|
||||
}
|
||||
|
||||
Ok(result)
|
||||
}
|
||||
|
||||
pub fn write(&self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
let mut header = self.header.clone();
|
||||
header.questions = self.questions.len() as u16;
|
||||
header.answers = self.answers.len() as u16;
|
||||
header.authoritative_entries = self.authorities.len() as u16;
|
||||
header.resource_entries = self.resources.len() as u16;
|
||||
|
||||
header.write(buffer)?;
|
||||
|
||||
for question in &self.questions {
|
||||
question.write(buffer)?;
|
||||
}
|
||||
for rec in &self.answers {
|
||||
rec.write(buffer)?;
|
||||
}
|
||||
for rec in &self.authorities {
|
||||
rec.write(buffer)?;
|
||||
}
|
||||
for rec in &self.resources {
|
||||
rec.write(buffer)?;
|
||||
}
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn display(&self) {
|
||||
println!("{:#?}", self.header);
|
||||
|
||||
for q in &self.questions {
|
||||
println!("{:#?}", q);
|
||||
}
|
||||
for rec in &self.answers {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
for rec in &self.authorities {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
for rec in &self.resources {
|
||||
println!("{:#?}", rec);
|
||||
}
|
||||
}
|
||||
}
|
||||
64
src/question.rs
Normal file
64
src/question.rs
Normal file
@@ -0,0 +1,64 @@
|
||||
use crate::buffer::BytePacketBuffer;
|
||||
use crate::Result;
|
||||
|
||||
#[derive(PartialEq, Eq, Debug, Clone, Hash, Copy)]
|
||||
pub enum QueryType {
|
||||
UNKNOWN(u16),
|
||||
A, // 1
|
||||
NS, // 2
|
||||
CNAME, // 5
|
||||
MX, // 15
|
||||
AAAA, // 28
|
||||
}
|
||||
|
||||
impl QueryType {
|
||||
pub fn to_num(&self) -> u16 {
|
||||
match *self {
|
||||
QueryType::UNKNOWN(x) => x,
|
||||
QueryType::A => 1,
|
||||
QueryType::NS => 2,
|
||||
QueryType::CNAME => 5,
|
||||
QueryType::MX => 15,
|
||||
QueryType::AAAA => 28,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn from_num(num: u16) -> QueryType {
|
||||
match num {
|
||||
1 => QueryType::A,
|
||||
2 => QueryType::NS,
|
||||
5 => QueryType::CNAME,
|
||||
15 => QueryType::MX,
|
||||
28 => QueryType::AAAA,
|
||||
_ => QueryType::UNKNOWN(num),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Debug, Clone, PartialEq, Eq)]
|
||||
pub struct DnsQuestion {
|
||||
pub name: String,
|
||||
pub qtype: QueryType,
|
||||
}
|
||||
|
||||
impl DnsQuestion {
|
||||
pub fn new(name: String, qtype: QueryType) -> DnsQuestion {
|
||||
DnsQuestion { name, qtype }
|
||||
}
|
||||
|
||||
pub fn read(&mut self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
buffer.read_qname(&mut self.name)?;
|
||||
self.qtype = QueryType::from_num(buffer.read_u16()?);
|
||||
let _ = buffer.read_u16()?; // class
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
pub fn write(&self, buffer: &mut BytePacketBuffer) -> Result<()> {
|
||||
buffer.write_qname(&self.name)?;
|
||||
buffer.write_u16(self.qtype.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
249
src/record.rs
Normal file
249
src/record.rs
Normal file
@@ -0,0 +1,249 @@
|
||||
use std::net::Ipv4Addr;
|
||||
use std::net::Ipv6Addr;
|
||||
|
||||
use crate::buffer::BytePacketBuffer;
|
||||
use crate::question::QueryType;
|
||||
use crate::Result;
|
||||
|
||||
#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
|
||||
#[allow(dead_code)]
|
||||
pub enum DnsRecord {
|
||||
UNKNOWN {
|
||||
domain: String,
|
||||
qtype: u16,
|
||||
data_len: u16,
|
||||
ttl: u32,
|
||||
},
|
||||
A {
|
||||
domain: String,
|
||||
addr: Ipv4Addr,
|
||||
ttl: u32,
|
||||
},
|
||||
NS {
|
||||
domain: String,
|
||||
host: String,
|
||||
ttl: u32,
|
||||
},
|
||||
CNAME {
|
||||
domain: String,
|
||||
host: String,
|
||||
ttl: u32,
|
||||
},
|
||||
MX {
|
||||
domain: String,
|
||||
priority: u16,
|
||||
host: String,
|
||||
ttl: u32,
|
||||
},
|
||||
AAAA {
|
||||
domain: String,
|
||||
addr: Ipv6Addr,
|
||||
ttl: u32,
|
||||
},
|
||||
}
|
||||
|
||||
impl DnsRecord {
|
||||
pub fn ttl(&self) -> u32 {
|
||||
match self {
|
||||
DnsRecord::A { ttl, .. }
|
||||
| DnsRecord::NS { ttl, .. }
|
||||
| DnsRecord::CNAME { ttl, .. }
|
||||
| DnsRecord::MX { ttl, .. }
|
||||
| DnsRecord::AAAA { ttl, .. }
|
||||
| DnsRecord::UNKNOWN { ttl, .. } => *ttl,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn set_ttl(&mut self, new_ttl: u32) {
|
||||
match self {
|
||||
DnsRecord::A { ttl, .. }
|
||||
| DnsRecord::NS { ttl, .. }
|
||||
| DnsRecord::CNAME { ttl, .. }
|
||||
| DnsRecord::MX { ttl, .. }
|
||||
| DnsRecord::AAAA { ttl, .. }
|
||||
| DnsRecord::UNKNOWN { ttl, .. } => *ttl = new_ttl,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn read(buffer: &mut BytePacketBuffer) -> Result<DnsRecord> {
|
||||
let mut domain = String::new();
|
||||
buffer.read_qname(&mut domain)?;
|
||||
|
||||
let qtype_num = buffer.read_u16()?;
|
||||
let qtype = QueryType::from_num(qtype_num);
|
||||
let _ = buffer.read_u16()?;
|
||||
let ttl = buffer.read_u32()?;
|
||||
let data_len = buffer.read_u16()?;
|
||||
|
||||
match qtype {
|
||||
QueryType::A => {
|
||||
let raw_addr = buffer.read_u32()?;
|
||||
let addr = Ipv4Addr::new(
|
||||
((raw_addr >> 24) & 0xFF) as u8,
|
||||
((raw_addr >> 16) & 0xFF) as u8,
|
||||
((raw_addr >> 8) & 0xFF) as u8,
|
||||
((raw_addr >> 0) & 0xFF) as u8,
|
||||
);
|
||||
|
||||
Ok(DnsRecord::A { domain, addr, ttl })
|
||||
}
|
||||
QueryType::AAAA => {
|
||||
let raw_addr1 = buffer.read_u32()?;
|
||||
let raw_addr2 = buffer.read_u32()?;
|
||||
let raw_addr3 = buffer.read_u32()?;
|
||||
let raw_addr4 = buffer.read_u32()?;
|
||||
let addr = Ipv6Addr::new(
|
||||
((raw_addr1 >> 16) & 0xFFFF) as u16,
|
||||
((raw_addr1 >> 0) & 0xFFFF) as u16,
|
||||
((raw_addr2 >> 16) & 0xFFFF) as u16,
|
||||
((raw_addr2 >> 0) & 0xFFFF) as u16,
|
||||
((raw_addr3 >> 16) & 0xFFFF) as u16,
|
||||
((raw_addr3 >> 0) & 0xFFFF) as u16,
|
||||
((raw_addr4 >> 16) & 0xFFFF) as u16,
|
||||
((raw_addr4 >> 0) & 0xFFFF) as u16,
|
||||
);
|
||||
|
||||
Ok(DnsRecord::AAAA { domain, addr, ttl })
|
||||
}
|
||||
QueryType::NS => {
|
||||
let mut ns = String::new();
|
||||
buffer.read_qname(&mut ns)?;
|
||||
|
||||
Ok(DnsRecord::NS {
|
||||
domain,
|
||||
host: ns,
|
||||
ttl,
|
||||
})
|
||||
}
|
||||
QueryType::CNAME => {
|
||||
let mut cname = String::new();
|
||||
buffer.read_qname(&mut cname)?;
|
||||
|
||||
Ok(DnsRecord::CNAME {
|
||||
domain,
|
||||
host: cname,
|
||||
ttl,
|
||||
})
|
||||
}
|
||||
QueryType::MX => {
|
||||
let priority = buffer.read_u16()?;
|
||||
let mut mx = String::new();
|
||||
buffer.read_qname(&mut mx)?;
|
||||
|
||||
Ok(DnsRecord::MX {
|
||||
domain,
|
||||
priority,
|
||||
host: mx,
|
||||
ttl,
|
||||
})
|
||||
}
|
||||
QueryType::UNKNOWN(_) => {
|
||||
buffer.step(data_len as usize)?;
|
||||
|
||||
Ok(DnsRecord::UNKNOWN {
|
||||
domain,
|
||||
qtype: qtype_num,
|
||||
data_len,
|
||||
ttl,
|
||||
})
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pub fn write(&self, buffer: &mut BytePacketBuffer) -> Result<usize> {
|
||||
let start_pos = buffer.pos();
|
||||
|
||||
match *self {
|
||||
DnsRecord::A {
|
||||
ref domain,
|
||||
ref addr,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::A.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
buffer.write_u16(4)?;
|
||||
|
||||
let octets = addr.octets();
|
||||
buffer.write_u8(octets[0])?;
|
||||
buffer.write_u8(octets[1])?;
|
||||
buffer.write_u8(octets[2])?;
|
||||
buffer.write_u8(octets[3])?;
|
||||
}
|
||||
DnsRecord::NS {
|
||||
ref domain,
|
||||
ref host,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::NS.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
|
||||
let pos = buffer.pos();
|
||||
buffer.write_u16(0)?;
|
||||
buffer.write_qname(host)?;
|
||||
|
||||
let size = buffer.pos() - (pos + 2);
|
||||
buffer.set_u16(pos, size as u16)?;
|
||||
}
|
||||
DnsRecord::CNAME {
|
||||
ref domain,
|
||||
ref host,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::CNAME.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
|
||||
let pos = buffer.pos();
|
||||
buffer.write_u16(0)?;
|
||||
buffer.write_qname(host)?;
|
||||
|
||||
let size = buffer.pos() - (pos + 2);
|
||||
buffer.set_u16(pos, size as u16)?;
|
||||
}
|
||||
DnsRecord::MX {
|
||||
ref domain,
|
||||
priority,
|
||||
ref host,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::MX.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
|
||||
let pos = buffer.pos();
|
||||
buffer.write_u16(0)?;
|
||||
buffer.write_u16(priority)?;
|
||||
buffer.write_qname(host)?;
|
||||
|
||||
let size = buffer.pos() - (pos + 2);
|
||||
buffer.set_u16(pos, size as u16)?;
|
||||
}
|
||||
DnsRecord::AAAA {
|
||||
ref domain,
|
||||
ref addr,
|
||||
ttl,
|
||||
} => {
|
||||
buffer.write_qname(domain)?;
|
||||
buffer.write_u16(QueryType::AAAA.to_num())?;
|
||||
buffer.write_u16(1)?;
|
||||
buffer.write_u32(ttl)?;
|
||||
buffer.write_u16(16)?;
|
||||
|
||||
for octet in &addr.segments() {
|
||||
buffer.write_u16(*octet)?;
|
||||
}
|
||||
}
|
||||
DnsRecord::UNKNOWN { .. } => {
|
||||
println!("Skipping record: {:?}", self);
|
||||
}
|
||||
}
|
||||
|
||||
Ok(buffer.pos() - start_pos)
|
||||
}
|
||||
}
|
||||
79
src/stats.rs
Normal file
79
src/stats.rs
Normal file
@@ -0,0 +1,79 @@
|
||||
use std::time::Instant;
|
||||
|
||||
pub struct ServerStats {
|
||||
queries_total: u64,
|
||||
queries_forwarded: u64,
|
||||
queries_cached: u64,
|
||||
queries_blocked: u64,
|
||||
queries_local: u64,
|
||||
upstream_errors: u64,
|
||||
started_at: Instant,
|
||||
}
|
||||
|
||||
pub enum QueryPath {
|
||||
Local,
|
||||
Cached,
|
||||
Forwarded,
|
||||
Blocked,
|
||||
UpstreamError,
|
||||
}
|
||||
|
||||
impl QueryPath {
|
||||
pub fn as_str(&self) -> &'static str {
|
||||
match self {
|
||||
QueryPath::Local => "LOCAL",
|
||||
QueryPath::Cached => "CACHED",
|
||||
QueryPath::Forwarded => "FORWARD",
|
||||
QueryPath::Blocked => "BLOCKED",
|
||||
QueryPath::UpstreamError => "SERVFAIL",
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl ServerStats {
|
||||
pub fn new() -> Self {
|
||||
ServerStats {
|
||||
queries_total: 0,
|
||||
queries_forwarded: 0,
|
||||
queries_cached: 0,
|
||||
queries_blocked: 0,
|
||||
queries_local: 0,
|
||||
upstream_errors: 0,
|
||||
started_at: Instant::now(),
|
||||
}
|
||||
}
|
||||
|
||||
pub fn record(&mut self, path: QueryPath) -> u64 {
|
||||
self.queries_total += 1;
|
||||
match path {
|
||||
QueryPath::Local => self.queries_local += 1,
|
||||
QueryPath::Cached => self.queries_cached += 1,
|
||||
QueryPath::Forwarded => self.queries_forwarded += 1,
|
||||
QueryPath::Blocked => self.queries_blocked += 1,
|
||||
QueryPath::UpstreamError => self.upstream_errors += 1,
|
||||
}
|
||||
self.queries_total
|
||||
}
|
||||
|
||||
pub fn total(&self) -> u64 {
|
||||
self.queries_total
|
||||
}
|
||||
|
||||
pub fn log_summary(&self) {
|
||||
let uptime = self.started_at.elapsed();
|
||||
let hours = uptime.as_secs() / 3600;
|
||||
let mins = (uptime.as_secs() % 3600) / 60;
|
||||
let secs = uptime.as_secs() % 60;
|
||||
|
||||
log::info!(
|
||||
"STATS | uptime {}h{}m{}s | total {} | fwd {} | cached {} | local {} | blocked {} | errors {}",
|
||||
hours, mins, secs,
|
||||
self.queries_total,
|
||||
self.queries_forwarded,
|
||||
self.queries_cached,
|
||||
self.queries_local,
|
||||
self.queries_blocked,
|
||||
self.upstream_errors,
|
||||
);
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user