fix(api): restore reverse-proxy IP resolution for /api/me

[bashrusakh]

Summary

• Restore X-Real-IP / X-Forwarded-For resolution in /api/me before peer lookup.
• Keep ?asn= disambiguation for shared-IP peers.
• Add regression tests for client-IP resolution.

Why

• Reverse-proxied deployments (nginx) were seeing the proxy IP instead of the real client.

Validation

• dotnet test BGPLite.Tests/BGPLite.Tests.csproj --no-restore
• dotnet format BGPLite.sln --verify-no-changes

Risk

• /api/me again trusts standard reverse-proxy headers when present, matching the prior behavior.

Closes #23

Summary by CodeRabbit

• New Features

  • Improved peer lookup for the “me” endpoint, including support for identifying the correct peer when multiple peers share an IP by using an ASN filter.
  • Client IP detection is now more reliable behind proxies, using forwarded headers before falling back to the remote address.

• Bug Fixes

  • Communities are now returned from the correct peer record, ensuring peer-specific data is shown accurately.
  • Peer records are now treated as unique per IP and ASN combination, reducing ambiguity and duplicate matches.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR reworks peer identity to be scoped by (Ip, Asn) instead of Ip alone. It adds a unique database index migration, a GetPeersByIp store method, ASN-based disambiguation in /api/me (with 409 on ambiguity) and peer-id-based community lookup, a ResolveClientIp helper, associated tests, and README updates.

Changes

Peer identity by IP+ASN

Layer / File(s)	Summary
Peer index migration and GetPeersByIp storage BGPLite.Api/BgpDbContext.cs, BGPLite.Api/PeerStore.cs, BGPLite.Tests/PeerStoreKeyingTests.cs	Adds unique (Ip, Asn) index migration replacing the legacy IP-only index, a new GetPeersByIp method, and tests for idempotent peer creation, scoped session status, and per-peer-id community storage.
/api/me and /api/peer ASN disambiguation BGPLite.Api/ManagementApi.cs, README.md	HandleGetMe filters peers by optional ?asn= query param, returning null for no match and 409 for ambiguous matches; HandleGetPeer retrieves communities by peer id; README documents the updated /api/me endpoint.
Client IP resolution helper BGPLite.Api/ManagementApi.cs, BGPLite.Tests/ManagementApiClientIpTests.cs	Adds ResolveClientIp prioritizing X-Real-IP, X-Forwarded-For, then remote endpoint, with tests for all three cases.
Test project wiring BGPLite.Api/BGPLite.Api.csproj, BGPLite.Tests/BGPLite.Tests.csproj	Adds InternalsVisibleTo for BGPLite.Tests and reorders project references.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant ManagementApi
  participant PeerStore
  participant Database
  Client->>ManagementApi: GET /api/me?asn=...
  ManagementApi->>ManagementApi: ResolveClientIp(headers, remoteEndpoint)
  ManagementApi->>PeerStore: GetPeersByIp(clientIp)
  PeerStore->>Database: Query Peers by Ip
  Database-->>PeerStore: Matching rows
  PeerStore-->>ManagementApi: List of PeerInfo
  ManagementApi->>ManagementApi: Filter by asn
  alt no match
    ManagementApi-->>Client: peer: null
  else multiple matches
    ManagementApi-->>Client: 409 Ambiguous peer
  else single match
    ManagementApi-->>Client: peer info with communities
  end

Loading

Related issues: #23 — /api/me disambiguation for peers sharing a source IP is addressed via optional ?asn= filtering and a 409 response on ambiguity.

Suggested labels: enhancement, api, database

Suggested reviewers: ruhex

🐰 A rabbit hops where IPs collide,

Now ASN whispers pick the right guide,

Indexes swapped, unique and clean,

No more mixing peers unseen,

Hop, hop — the network's tidy tide.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is concise and accurately describes the main user-facing change to /api/me behind reverse proxies.
Linked Issues check	✅ Passed	The PR adds ASN-based disambiguation for /api/me and regression tests for shared-IP peers, which matches #23's expected fix.
Out of Scope Changes check	✅ Passed	The changes stay focused on /api/me peer resolution, related storage/index updates, tests, and documentation.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (1)

BGPLite.Tests/ManagementApiClientIpTests.cs (1)

1-36: 🩺 Stability & Availability | 🔵 Trivial | ⚡ Quick win

Tests only cover the currently-implemented (unconditionally-trusting) behavior.

These tests validate the current header precedence but don't exercise a scenario where headers should be ignored (e.g., request not from a trusted proxy). Once trusted-proxy validation is added per the ResolveClientIp comment, add regression coverage for the "untrusted source falls back to remote endpoint despite spoofed headers" case.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@BGPLite.Tests/ManagementApiClientIpTests.cs` around lines 1 - 36, Add a
regression test in ManagementApiClientIpTests for the untrusted-source case:
when ResolveClientIp receives spoofed X-Real-IP / X-Forwarded-For values but the
request is not from a trusted proxy, it should ignore those headers and return
the remote endpoint. Reuse the existing ResolveClientIp test pattern, but
introduce a scenario that exercises the trusted-proxy validation path once it is
implemented.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@BGPLite.Tests/ManagementApiClientIpTests.cs`:
- Around line 1-36: Add a regression test in ManagementApiClientIpTests for the
untrusted-source case: when ResolveClientIp receives spoofed X-Real-IP /
X-Forwarded-For values but the request is not from a trusted proxy, it should
ignore those headers and return the remote endpoint. Reuse the existing
ResolveClientIp test pattern, but introduce a scenario that exercises the
trusted-proxy validation path once it is implemented.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: a3dbb06c-8e8c-4e6e-b73b-83d83b81d958

📥 Commits

Reviewing files that changed from the base of the PR and between 5ecd70c and 27c5aef.

📒 Files selected for processing (8)

• BGPLite.Api/BGPLite.Api.csproj
• BGPLite.Api/BgpDbContext.cs
• BGPLite.Api/ManagementApi.cs
• BGPLite.Api/PeerStore.cs
• BGPLite.Tests/BGPLite.Tests.csproj
• BGPLite.Tests/ManagementApiClientIpTests.cs
• BGPLite.Tests/PeerStoreKeyingTests.cs
• README.md

💤 Files with no reviewable changes (1)

• BGPLite.Api/BgpDbContext.cs