[WP] Support TCP segmentation on IMDS and increase IMDS event size

[Gui774ume]

What does this PR do?

Fix IMDS events by re-assembling segmented IMDS requests, and making the IMDS event buffer longer.

Motivation

Without this patch, we're missing IMDS events.

Describe how you validated your changes

Both unit and functional tests were added to validate this change.

[datadog-datadog-prod-us1-2]

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 78 Pipeline jobs failed

DataDog/datadog-agent | bazel:test:linux-amd64     

🔧 Fix in code (Fix with Cursor).

Panic: CWS warning: the trimmed map name `syscall_monitor` is not unique.

DataDog/datadog-agent | bazel:test:linux-arm64     

🔧 Fix in code (Fix with Cursor).

Panic: the trimmed map name `syscall_monitor` is not unique in bpf_maps_generator at pkg/security/secl/model/bpf_maps_generator/bpf_maps_generator.go:123.

DataDog/datadog-agent | bazel:test:macos-amd64     

🔧 Fix in code (Fix with Cursor).

Panic: trimmed map name 'syscall_monitor' is not unique at pkg/security/secl/model/bpf_maps_generator/bpf_maps_generator.go:123.

View all 78 failed jobs.

ℹ️ Info

🎯 Code Coverage (details)
• Patch Coverage: 43.11%
• Overall Coverage: 50.38% (-0.01%)

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[dd-octo-sts]

Files inventory check summary

File checks results against ancestor f053e31a:

Results for datadog-agent_7.81.0~devel.git.328.859f8cc.pipeline.116561568-1_amd64.deb:

Detected file changes:

1 Changed files:

• opt/datadog-agent/embedded/share/system-probe/ebpf/runtime-security-fentry.o:
  • Size changed: +12.46% (948.47 KiB) (7.43 MiB -> 8.36 MiB)

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: e5fa57b6-5f49-4886-bf84-7b26a95707ff

Baseline: f053e31
Comparison: 859f8cc
Diff

Optimization Goals: ✅ No significant changes detected

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	-1.06	[-4.04, +1.92]	1	Logs

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	quality_gate_idle_all_features	memory utilization	+4.73	[+4.69, +4.77]	1	Logs bounds checks dashboard
➖	file_tree	memory utilization	+3.85	[+3.74, +3.96]	1	Logs
➖	quality_gate_logs	% cpu utilization	+2.29	[+1.26, +3.33]	1	Logs bounds checks dashboard
➖	otlp_ingest_logs	memory utilization	+1.15	[+1.05, +1.25]	1	Logs
➖	ddot_metrics_sum_cumulativetodelta_exporter	memory utilization	+0.49	[+0.26, +0.73]	1	Logs
➖	docker_containers_memory	memory utilization	+0.38	[+0.29, +0.48]	1	Logs
➖	ddot_metrics_sum_cumulative	memory utilization	+0.28	[+0.13, +0.44]	1	Logs
➖	quality_gate_metrics_logs	memory utilization	+0.17	[-0.07, +0.42]	1	Logs bounds checks dashboard
➖	uds_dogstatsd_20mb_12k_contexts_20_senders	memory utilization	+0.17	[+0.12, +0.22]	1	Logs
➖	quality_gate_idle	memory utilization	+0.16	[+0.11, +0.21]	1	Logs bounds checks dashboard
➖	ddot_metrics_sum_delta	memory utilization	+0.07	[-0.12, +0.26]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	+0.03	[-0.36, +0.42]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	+0.02	[-0.42, +0.46]	1	Logs
➖	file_to_blackhole_0ms_latency	egress throughput	+0.01	[-0.48, +0.51]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.09, +0.10]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	-0.00	[-0.20, +0.20]	1	Logs
➖	uds_dogstatsd_to_api_v3	ingress throughput	-0.02	[-0.22, +0.19]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	-0.02	[-0.16, +0.11]	1	Logs
➖	ddot_metrics	memory utilization	-0.11	[-0.32, +0.09]	1	Logs
➖	otlp_ingest_metrics	memory utilization	-0.30	[-0.46, -0.15]	1	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-0.31	[-0.49, -0.12]	1	Logs
➖	ddot_logs	memory utilization	-1.01	[-1.08, -0.95]	1	Logs
➖	docker_containers_cpu	% cpu utilization	-1.06	[-4.04, +1.92]	1	Logs

Bounds Checks: ❌ Failed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	docker_containers_cpu	simple_check_run	10/10	704 ≥ 26
✅	docker_containers_memory	memory_usage	10/10	245.02MiB ≤ 370MiB
✅	docker_containers_memory	simple_check_run	10/10	722 ≥ 26
✅	file_to_blackhole_0ms_latency	memory_usage	10/10	0.16GiB ≤ 1.20GiB
✅	file_to_blackhole_0ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10	0.20GiB ≤ 1.20GiB
✅	file_to_blackhole_1000ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_100ms_latency	memory_usage	10/10	0.17GiB ≤ 1.20GiB
✅	file_to_blackhole_100ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_500ms_latency	memory_usage	10/10	0.18GiB ≤ 1.20GiB
✅	file_to_blackhole_500ms_latency	missed_bytes	10/10	0B = 0B
✅	quality_gate_idle	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	144.40MiB ≤ 147MiB	bounds checks dashboard
✅	quality_gate_idle	total_bytes_received	10/10	742.13KiB ≤ 819.20KiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
❌	quality_gate_idle_all_features	memory_usage	4/10	520.39MiB > 495MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	total_bytes_received	10/10	0.95MiB ≤ 1.25MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	177.71MiB ≤ 195MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_logs	total_bytes_received	10/10	264.36MiB ≤ 292MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	348.67 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	369.55MiB ≤ 430MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	total_bytes_received	10/10	0.94GiB ≤ 1.04GiB	bounds checks dashboard

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

CI Pass/Fail Decision

❌ Failed. Some Quality Gates were violated.

• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check memory_usage: 4/10 replicas passed. Failed 6 which is > 0. Gate FAILED.
• quality_gate_idle, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.