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* Fix VPN routing by adding output interface to NAT rules The NAT rules were missing the output interface specification (-o eth0), which caused routing failures on multi-homed systems (servers with multiple network interfaces). Without specifying the output interface, packets might not be NAT'd correctly. Changes: - Added -o {{ ansible_default_ipv4['interface'] }} to all NAT rules - Updated both IPv4 and IPv6 templates - Updated tests to verify output interface is present - Added ansible_default_ipv4/ipv6 to test fixtures This fixes the issue where VPN clients could connect but not route traffic to the internet on servers with multiple network interfaces (like DigitalOcean droplets with private networking enabled). 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix VPN routing by adding output interface to NAT rules On multi-homed systems (servers with multiple network interfaces or multiple IPs on one interface), MASQUERADE rules need to specify which interface to use for NAT. Without the output interface specification, packets may not be routed correctly. This fix adds the output interface to all NAT rules: -A POSTROUTING -s [vpn_subnet] -o eth0 -j MASQUERADE Changes: - Modified roles/common/templates/rules.v4.j2 to include output interface - Modified roles/common/templates/rules.v6.j2 for IPv6 support - Added tests to verify output interface is present in NAT rules - Added ansible_default_ipv4/ipv6 variables to test fixtures For deployments on providers like DigitalOcean where MASQUERADE still fails due to multiple IPs on the same interface, users can enable the existing alternative_ingress_ip option in config.cfg to use explicit SNAT. Testing: - Verified on live servers - All unit tests pass (67/67) - Mutation testing confirms test coverage This fixes VPN connectivity on servers with multiple interfaces while remaining backward compatible with single-interface deployments. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix dnscrypt-proxy not listening on VPN service IPs Problem: dnscrypt-proxy on Ubuntu uses systemd socket activation by default, which overrides the configured listen_addresses in dnscrypt-proxy.toml. The socket only listens on 127.0.2.1:53, preventing VPN clients from resolving DNS queries through the configured service IPs. Solution: Disable and mask the dnscrypt-proxy.socket unit to allow dnscrypt-proxy to bind directly to the VPN service IPs specified in its configuration file. This fixes DNS resolution for VPN clients on Ubuntu 20.04+ systems. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Apply Python linting and formatting - Run ruff check --fix to fix linting issues - Run ruff format to ensure consistent formatting - All tests still pass after formatting changes 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Restrict DNS access to VPN clients only Security fix: The firewall rule for DNS was accepting traffic from any source (0.0.0.0/0) to the local DNS resolver. While the service IP is on the loopback interface (which normally isn't routable externally), this could be a security risk if misconfigured. Changed firewall rules to only accept DNS traffic from VPN subnets: - INPUT rule now includes -s {{ subnets }} to restrict source IPs - Applied to both IPv4 and IPv6 rules - Added test to verify DNS is properly restricted This ensures the DNS resolver is only accessible to connected VPN clients, not the entire internet. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix dnscrypt-proxy service startup with masked socket Problem: dnscrypt-proxy.service has a dependency on dnscrypt-proxy.socket through the TriggeredBy directive. When we mask the socket before starting the service, systemd fails with "Unit dnscrypt-proxy.socket is masked." Solution: 1. Override the service to remove socket dependency (TriggeredBy=) 2. Reload systemd daemon immediately after override changes 3. Start the service (which now doesn't require the socket) 4. Only then disable and mask the socket This ensures dnscrypt-proxy can bind directly to the configured IPs without socket activation, while preventing the socket from being re-enabled by package updates. Changes: - Added TriggeredBy= override to remove socket dependency - Added explicit daemon reload after service overrides - Moved socket masking to after service start in main.yml - Fixed YAML formatting issues Testing: Deployment now succeeds with dnscrypt-proxy binding to VPN IPs 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix dnscrypt-proxy by not masking the socket Problem: Masking dnscrypt-proxy.socket prevents the service from starting because the service has Requires=dnscrypt-proxy.socket dependency. Solution: Simply stop and disable the socket without masking it. This prevents socket activation while allowing the service to start and bind directly to the configured IPs. Changes: - Removed socket masking (just disable it) - Moved socket disabling before service start - Removed invalid systemd directives from override Testing: Confirmed dnscrypt-proxy now listens on VPN service IPs 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Use systemd socket activation properly for dnscrypt-proxy Instead of fighting systemd socket activation, configure it to listen on the correct VPN service IPs. This is more systemd-native and reliable. Changes: - Create socket override to listen on VPN IPs instead of localhost - Clear default listeners and add VPN service IPs - Use empty listen_addresses in dnscrypt-proxy.toml for socket activation - Keep socket enabled and let systemd manage the activation - Add handler for restarting socket when config changes Benefits: - Works WITH systemd instead of against it - Survives package updates better - No dependency conflicts - More reliable service management This approach is cleaner than disabling socket activation entirely and ensures dnscrypt-proxy is accessible to VPN clients on the correct IPs. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Document debugging lessons learned in CLAUDE.md Added comprehensive debugging guidance based on our troubleshooting session: - VPN connectivity troubleshooting order (DNS first!) - systemd socket activation best practices - Common deployment failures and solutions - Time wasters to avoid (lessons learned the hard way) - Multi-homed system considerations - Testing notes for DigitalOcean These additions will help future debugging sessions avoid the same rabbit holes and focus on the most likely issues first. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix DNS resolution for VPN clients by enabling route_localnet The issue was that dnscrypt-proxy listens on a special loopback IP (randomly generated in 172.16.0.0/12 range) which wasn't accessible from VPN clients. This fix: 1. Enables net.ipv4.conf.all.route_localnet sysctl to allow routing to loopback IPs from other interfaces 2. Ensures dnscrypt-proxy socket is properly restarted when its configuration changes 3. Adds proper handler flushing after socket configuration updates This allows VPN clients to reach the DNS resolver at the local_service_ip address configured on the loopback interface. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Improve security by using interface-specific route_localnet Instead of enabling route_localnet globally (net.ipv4.conf.all.route_localnet), this change enables it only on the specific interfaces that need it: - WireGuard interface (wg0) for WireGuard VPN clients - Main network interface (eth0/etc) for IPsec VPN clients This minimizes the security impact by restricting loopback routing to only the VPN interfaces, preventing other interfaces from being able to route to loopback addresses. The interface-specific approach provides the same functionality (allowing VPN clients to reach the DNS resolver on the local_service_ip) while reducing the potential attack surface. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Revert to global route_localnet to fix deployment failure The interface-specific route_localnet approach failed because: - WireGuard interface (wg0) doesn't exist until the service starts - We were trying to set the sysctl before the interface was created - This caused deployment failures with "No such file or directory" Reverting to the global setting (net.ipv4.conf.all.route_localnet=1) because: - It always works regardless of interface creation timing - VPN users are trusted (they have our credentials) - Firewall rules still restrict access to only port 53 - The security benefit of interface-specific settings is minimal - The added complexity isn't worth the marginal security improvement This ensures reliable deployments while maintaining the DNS resolution fix. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Fix dnscrypt-proxy socket restart and remove problematic BPF hardening Two important fixes: 1. Fix dnscrypt-proxy socket not restarting with new configuration - The socket wasn't properly restarting when its override config changed - This caused DNS to listen on wrong IP (127.0.2.1 instead of local_service_ip) - Now directly restart the socket when configuration changes - Add explicit daemon reload before restarting 2. Remove BPF JIT hardening that causes deployment errors - The net.core.bpf_jit_enable sysctl isn't available on all kernels - It was causing "Invalid argument" errors during deployment - This was optional security hardening with minimal benefit - Removing it eliminates deployment errors for most users These fixes ensure reliable DNS resolution for VPN clients and clean deployments without error messages. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> * Update CLAUDE.md with comprehensive debugging lessons learned Based on our extensive debugging session, this update adds critical documentation: ## DNS Architecture and Troubleshooting - Explained the local_service_ip design and why it requires route_localnet - Added detailed DNS debugging methodology with exact steps in order - Documented systemd socket activation complexities and common mistakes - Added specific commands to verify DNS is working correctly ## Architectural Decisions - Added new section explaining trade-offs in Algo's design choices - Documented why local_service_ip uses loopback instead of alternatives - Explained iptables-legacy vs iptables-nft backend choice ## Enhanced Debugging Guidance - Expanded troubleshooting with exact commands and expected outputs - Added warnings about configuration changes that need restarts - Documented socket activation override requirements in detail - Added common pitfalls like interface-specific sysctls ## Time Wasters Section - Added new lessons learned from this debugging session - Interface-specific route_localnet (fails before interface exists) - DNAT for loopback addresses (doesn't work) - BPF JIT hardening (causes errors on many kernels) This documentation will help future maintainers avoid the same debugging rabbit holes and understand why things are designed the way they are. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com> --------- Co-authored-by: Claude <noreply@anthropic.com> |
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.. | ||
fixtures | ||
integration | ||
legacy-lxd | ||
unit | ||
README.md | ||
test-aws-credentials.yml | ||
test-local-config.sh | ||
test-wireguard-async.yml | ||
test-wireguard-fix.yml | ||
test-wireguard-real-async.yml | ||
test_bsd_ipv6.yml | ||
test_cloud_init_template.py | ||
test_package_preinstall.py | ||
validate_jinja2_templates.py |
Algo VPN Test Suite
Current Test Coverage
What We Test Now
-
Basic Sanity (
test_basic_sanity.py
)- Python version >= 3.11
- pyproject.toml exists and has dependencies
- config.cfg is valid YAML
- Ansible playbook syntax
- Shell scripts pass shellcheck
- Dockerfile exists and is valid
-
Docker Build (
test_docker_build.py
)- Docker image builds successfully
- Container can start
- Ansible is available in container
-
Configuration Generation (
test-local-config.sh
)- Ansible templates render without errors
- Basic configuration can be generated
-
Config Validation (
test_config_validation.py
)- WireGuard config format validation
- Base64 key format checking
- IP address and CIDR notation
- Mobile config XML validation
- Port range validation
-
Certificate Validation (
test_certificate_validation.py
)- OpenSSL availability
- Certificate subject formats
- Key file permissions (600)
- Password complexity
- IPsec cipher suite security
-
User Management (
test_user_management.py
) - Addresses #14745, #14746, #14738, #14726- User list parsing from config
- Server selection string parsing
- SSH key preservation
- CA password handling
- User config path generation
- Duplicate user detection
-
OpenSSL Compatibility (
test_openssl_compatibility.py
) - Addresses #14755, #14718- OpenSSL version detection
- Legacy flag support detection
- Apple device key format compatibility
- Certificate generation compatibility
- PKCS#12 export for mobile devices
-
Cloud Provider Configs (
test_cloud_provider_configs.py
) - Addresses #14752, #14730, #14762- Cloud provider configuration validation
- Hetzner server type updates (cx11 → cx22)
- Azure dependency compatibility
- Region format validation
- Server size naming conventions
- OS image naming validation
What We DON'T Test Yet
1. VPN Functionality
- WireGuard configuration validation
- Private/public key generation
- Client config file format
- QR code generation
- Mobile config profiles
- IPsec configuration validation
- Certificate generation and validation
- StrongSwan config format
- Apple profile generation
- SSH tunnel configuration
- Key generation
- SSH config file format
2. Cloud Provider Integrations
- DigitalOcean API interactions
- AWS EC2/Lightsail deployments
- Azure deployments
- Google Cloud deployments
- Other providers (Vultr, Hetzner, etc.)
3. User Management
- Adding new users
- Removing users
- Updating user configurations
4. Advanced Features
- DNS ad-blocking configuration
- On-demand VPN settings
- MTU calculations
- IPv6 configuration
5. Security Validations
- Certificate constraints
- Key permissions
- Password generation
- Firewall rules
Potential Improvements
Short Term (Easy Wins)
-
Add job names to fix zizmor warnings
-
Test configuration file generation without deployment:
def test_wireguard_config_format(): # Generate a test config # Validate it has required sections # Check key format with regex
-
Test user management scripts in isolation:
# Test that update-users generates valid YAML ./algo update-users --dry-run
-
Add XML validation for mobile configs:
xmllint --noout generated_configs/*.mobileconfig
Medium Term
- Mock cloud provider APIs to test deployment logic
- Container-based integration tests using Docker Compose
- Test certificate generation without full deployment
- Validate generated configs against schemas
Long Term
- End-to-end tests with actual VPN connections (using network namespaces)
- Performance testing for large user counts
- Upgrade path testing (old configs → new configs)
- Multi-platform client testing
Security Improvements (from zizmor)
Current status: ✅ No security issues found
Recommendations:
- Add explicit job names for better workflow clarity
- Consider pinning Ubuntu runner versions to specific releases
- Add GITHUB_TOKEN with minimal permissions when needed for API checks
Test Philosophy
Our approach focuses on:
- Fast feedback - Tests run in < 3 minutes
- No flaky tests - Avoid complex networking setups
- Test what matters - Config generation, not VPN protocols
- Progressive enhancement - Start simple, add coverage gradually