Add logs for allowed traffic in L7 NetworkPolicy

The solution adds logs with event type http for allowed
traffic in L7 NetworkPolicy. It also adds log support for
DNS, TLS as later supported by L7NP.

Signed-off-by: Qiyue Yao <yaoq@vmware.com>

docs/antrea-l7-network-policy.md

@@ -292,9 +292,38 @@ spec:
 
 Layer 7 traffic that matches the NetworkPolicy will be logged in an event
 triggered log file (`/var/log/antrea/networkpolicy/l7engine/eve-YEAR-MONTH-DAY.json`).
-The event type for this log is `alert`. If `enableLogging` is set for the rule,
-packets that match the rule will also be logged in addition to the event with
-event type `packet`. Below is an example of the two event types.
+Logs are categorized by **event_type**. The event type for allowed traffic is `http`,
+for dropped traffic is `alert`. If `enableLogging` is set for the rule, dropped packets
+that match the rule will also be logged in addition to the event with
+event type `packet`. Below are examples for allow, drop, packet scenarios.
+
+Allow ingress from client (10.10.1.8) to web (10.10.1.7/public/*)
+
+```json
+{
+  "timestamp": "2024-02-22T21:26:07.074791+0000",
+  "flow_id": 757085628206447,
+  "in_iface": "antrea-l7-tap0",
+  "event_type": "http",
+  "vlan": [1],
+  "src_ip": "10.10.1.8",
+  "src_port": 44132,
+  "dest_ip": "10.10.1.7",
+  "dest_port": 80,
+  "proto": "TCP",
+  "tx_id": 0,
+  "http": {
+      "hostname": "10.10.1.7",
+      "url": "/public/main.html",
+      "http_user_agent": "Wget/1.21.1",
+      "http_content_type": "text/html",
+      "http_method": "GET",
+      "protocol": "HTTP/1.1",
+      "status": 404,
+      "length": 153
+  }
+}
+```
 
 Deny ingress from client (10.10.1.5) to web (10.10.1.4/admin)
 
@@ -341,6 +370,8 @@ Deny ingress from client (10.10.1.5) to web (10.10.1.4/admin)
 }
 ```
 
+Additional packet log when `enableLogging` is set
+
 ```json
 {
   "timestamp": "2023-03-09T20:00:28.225016+0000",

pkg/agent/controller/networkpolicy/l7engine/reconciler.go

@@ -76,6 +76,12 @@ outputs:
       types:
         - alert:
             tagged-packets: yes
+        - http:
+            extended: yes
+        - dns:
+            version: 2
+        - tls:
+            extended: yes
   - eve-log:
       enabled: yes
       filetype: unix_stream