feat(events): introduce dns_request_kernel event

[AlonZivony]

1. Explain what the PR does

Added a new event dns_request_kernel to capture DNS queries as a normal kprobe event, providing a reliable and efficient alternative to network packet-based monitoring. The downside is that it captures only UDP requests, missing more sophisticated implementations using TCP and HTTP.

2. Explain how to test it

3. Other comments

[Copilot]

Pull Request Overview

This PR introduces a new kernel-level DNS monitoring event dns_request_kernel that captures DNS queries directly at the kernel level using a kprobe on udp_sendmsg, providing a more reliable and efficient alternative to network packet-based DNS monitoring.

• Adds dns_request_kernel event that hooks the udp_sendmsg kernel function to capture UDP DNS requests on port 53
• Implements support for both iovec and ubuf message formats with DNS payload parsing
• Includes comprehensive testing infrastructure with C test clients and end-to-end test signatures

Reviewed Changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
pkg/ebpf/c/tracee.bpf.c	Implements the core kprobe hook for udp_sendmsg with DNS filtering and payload extraction
pkg/events/derive/net_kernel.go	Adds DNS message parsing logic to extract hostname and query type from captured payloads
pkg/events/core.go	Defines the new DnsRequestKernelBase and DnsRequestKernel event definitions
tests/e2e-inst-signatures/scripts/dns_client/	Test clients for validating DNS request capture functionality
docs/docs/events/builtin/network/dns_request_kernel.md	Comprehensive documentation for the new event

[yanivagman]

Please rebase.
Some changes were made to the event documentation location and format that will require changes from your side