Documentation for Firewall filter

While writing the docs, I found a typo in the name of the Filter, so
included that as well.

Closes #158
Closes #343

docs/src/SUMMARY.md

@@ -17,6 +17,7 @@
     - [Load Balancer](./filters/load_balancer.md)
     - [Local Rate Limit](./filters/local_rate_limit.md)
     - [Token Router](./filters/token_router.md)
+    - [Firewall](./filters/firewall.md)
     - [Writing Custom Filters](./filters/writing_custom_filters.md)
 - [Integrations](./integrations.md)
 - [Administration](./admin.md)

docs/src/filters.md

@@ -107,6 +107,7 @@ Quilkin includes several filters out of the box.
 | [CaptureBytes] | Capture specific bytes from a packet and store them in [filter dynamic metadata](#filter-dynamic-metadata). |
 | [TokenRouter] | Send packets to endpoints based on metadata. |
 | [Compress](./filters/compress.md) | Compress and decompress packets data. |
+| [Firewall](./filters/firewall.md) | Allowing/blocking traffic by IP and port. |
 
 ### FilterConfig <a name="filter-config"></a>
 Represents configuration for a filter instance.

docs/src/filters/firewall.md

@@ -0,0 +1,96 @@
+# Firewall
+
+The `Firewall` filter's job is to allow or block traffic depending on if the incoming traffic's IP and port matches
+the rules set on the Firewall filter.
+
+#### Filter name
+```text
+quilkin.extensions.filters.firewall.v1alpha1.Firewall
+```
+
+### Configuration Examples
+```rust
+# let yaml = "
+version: v1alpha1
+static:
+  filters:
+    - name: quilkin.extensions.filters.firewall.v1alpha1.Firewall
+      config:
+        on_read:
+          - action: ALLOW
+            source: 192.168.51.0/24
+            ports:
+               - 10
+               - 1000-7000
+        on_write: 
+          - action: DENY
+            source: 192.168.51.0/24
+            ports:
+               - 7000
+  endpoints:
+    - address: 127.0.0.1:7001
+# ";
+# let config = quilkin::config::Config::from_reader(yaml.as_bytes()).unwrap();
+# assert_eq!(config.source.get_static_filters().unwrap().len(), 1);
+# quilkin::Builder::from(std::sync::Arc::new(config)).validate().unwrap();
+```
+
+### Configuration Options
+
+```yaml
+properties:
+  on_read:
+    '$ref': '#/definitions/rules'
+    description: Rules to match against when reading packets to the local listening port.
+  on_write:
+    type: array
+    '$ref': '#/definitions/rules'
+    description: Rules to match against when writing packets to the local listening port.
+
+definitions:
+  rules:
+    type: array
+    description: Rules to match against when writing packets to the local listening port.
+    items:
+      type: object
+      properties:
+        action:
+          type: string
+          description: |
+            Whether or not a matching Rule should Allow or Deny access
+            - DENY: If the rule matches, block the traffic.
+            - ALLOW: If the rule matches, allow the traffic through.
+          enum: ['ALLOW', 'DENY']
+        source:
+          type: string
+          description: A CIDR network range, either in a v4 or v6 format.
+        ports:
+          type: array
+          description: Array of singular ports or port ranges to match against.
+          items:
+            type: string
+            description: |
+              Either in the format of "10" for a singular port or "10-100" for a port range where 
+              min is inclusive, and max is exclusive.
+      required: ['action', 'source', 'ports']
+```
+
+#### Rule Evaluation
+
+The Firewall filter supports DENY and ALLOW actions for access control. When multiple DENY and ALLOW actions are used 
+for a workload at the same time, the evaluation is processed in the order it is configured, with the first matching 
+rule deciding if the request is allowed or denied:
+
+1. If a rule action is ALLOW, and it matches the request, then the entire request is allowed.
+2. If a rule action is DENY and it matches the request, then the entire request is denied.
+3. If none of the configured rules match, then the request is denied.
+
+### Metrics
+
+* `quilkin_filter_Firewall_packets_denied_total` Total number of packets denied.
+* `quilkin_filter_Firewall_packets_allowed_total` Total number of packets allowed.
+
+Both metrics have the label `event`, with a value of `read` or `write` which corresponds to either `on_read` or 
+`on_write` events within the Filter.
+
+[filter-dynamic-metadata]: ./filter.md#filter-dynamic-metadata

src/filters/firewall.rs

@@ -30,7 +30,7 @@ mod metrics;
 
 pub use config::{Action, Config, PortRange, PortRangeError, Rule};
 
-pub const NAME: &str = "quilkin.extensions.filters.compress.v1alpha1.Firewall";
+pub const NAME: &str = "quilkin.extensions.filters.firewall.v1alpha1.Firewall";
 
 pub fn factory(base: &Logger) -> DynFilterFactory {
     Box::from(FirewallFactory::new(base))

src/lib.rs

@@ -53,4 +53,5 @@ mod external_doc_tests {
     #![doc = include_str!("../docs/src/filters/capture_bytes.md")]
     #![doc = include_str!("../docs/src/filters/token_router.md")]
     #![doc = include_str!("../docs/src/filters/compress.md")]
+    #![doc = include_str!("../docs/src/filters/firewall.md")]
 }