mirror of
https://github.com/Control-D-Inc/ctrld.git
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4792183c0d
This commit extends the documentation effort by adding detailed explanatory comments to key CLI components and core functionality throughout the cmd/ directory. The changes focus on explaining WHY certain logic is needed, not just WHAT the code does, improving code maintainability and helping developers understand complex business decisions. Key improvements: - Main entry points: Document CLI initialization, logging setup, and cache configuration with reasoning for design decisions - DNS proxy core: Explain DNS proxy constants, data structures, and core processing pipeline for handling DNS queries - Service management: Document service command structure, configuration patterns, and platform-specific service handling - Logging infrastructure: Explain log buffer management, level encoders, and log formatting decisions for different use cases - Metrics and monitoring: Document Prometheus metrics structure, HTTP endpoints, and conditional metric collection for performance - Network handling: Explain Linux-specific network interface filtering, virtual interface detection, and DNS configuration management - Hostname validation: Document RFC1123 compliance and DNS naming standards for system compatibility - Mobile integration: Explain HTTP retry logic, fallback mechanisms, and mobile platform integration patterns - Connection management: Document connection wrapper design to prevent log pollution during process lifecycle Technical details: - Added explanatory comments to 11 additional files in cmd/cli/ - Maintained consistent documentation style and format - Preserved all existing functionality while improving code clarity - Enhanced understanding of complex business logic and platform-specific behavior These comments help future developers understand the reasoning behind complex decisions, making the codebase more maintainable and reducing the risk of incorrect modifications during maintenance.
68 lines
2.1 KiB
Go
68 lines
2.1 KiB
Go
package cli
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import (
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"context"
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"net"
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"net/netip"
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"os"
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"strings"
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"tailscale.com/net/netmon"
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"github.com/Control-D-Inc/ctrld"
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)
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// patchNetIfaceName patches network interface names on Linux
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// This is a no-op on Linux as interface names don't need special handling
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func patchNetIfaceName(iface *net.Interface) (bool, error) { return true, nil }
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// validInterface reports whether the *net.Interface is a valid one.
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// Only non-virtual interfaces are considered valid.
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// This prevents DNS configuration on virtual interfaces like docker, veth, etc.
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func validInterface(iface *net.Interface, validIfacesMap map[string]struct{}) bool {
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_, ok := validIfacesMap[iface.Name]
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return ok
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}
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// validInterfacesMap returns a set containing non virtual interfaces.
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// This filters out virtual interfaces to ensure DNS is only configured on physical interfaces
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func validInterfacesMap(ctx context.Context) map[string]struct{} {
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m := make(map[string]struct{})
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vis := virtualInterfaces(ctx)
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netmon.ForeachInterface(func(i netmon.Interface, prefixes []netip.Prefix) {
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if _, existed := vis[i.Name]; existed {
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return
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}
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m[i.Name] = struct{}{}
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})
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// Fallback to the default route interface if found nothing.
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// This ensures we always have at least one interface to configure
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if len(m) == 0 {
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defaultRoute, err := netmon.DefaultRoute()
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if err != nil {
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return m
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}
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m[defaultRoute.InterfaceName] = struct{}{}
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}
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return m
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}
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// virtualInterfaces returns a map of virtual interfaces on the current machine.
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// This reads from /sys/devices/virtual/net to identify virtual network interfaces
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// Virtual interfaces should not have DNS configured as they don't represent physical network connections
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func virtualInterfaces(ctx context.Context) map[string]struct{} {
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logger := ctrld.LoggerFromCtx(ctx)
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s := make(map[string]struct{})
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entries, err := os.ReadDir("/sys/devices/virtual/net")
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if err != nil {
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logger.Error().Err(err).Msg("failed to read /sys/devices/virtual/net")
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return nil
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}
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for _, entry := range entries {
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if entry.IsDir() {
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s[strings.TrimSpace(entry.Name())] = struct{}{}
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}
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}
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return s
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}
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