mirror of
https://github.com/Control-D-Inc/ctrld.git
synced 2026-02-03 22:18:39 +00:00
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.
107 lines
3.0 KiB
Go
107 lines
3.0 KiB
Go
package cli
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import (
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"net"
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"net/netip"
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"os/exec"
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"tailscale.com/control/controlknobs"
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"tailscale.com/health"
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"tailscale.com/util/dnsname"
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"github.com/Control-D-Inc/ctrld"
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"github.com/Control-D-Inc/ctrld/internal/dns"
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)
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// allocateIP allocates an IP address on the specified interface
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// sudo ifconfig lo0 127.0.0.53 alias
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func allocateIP(ip string) error {
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cmd := exec.Command("ifconfig", "lo0", ip, "alias")
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if err := cmd.Run(); err != nil {
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mainLog.Load().Error().Err(err).Msg("allocateIP failed")
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return err
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}
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return nil
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}
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// deAllocateIP deallocates an IP address from the specified interface
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func deAllocateIP(ip string) error {
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cmd := exec.Command("ifconfig", "lo0", ip, "-alias")
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if err := cmd.Run(); err != nil {
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mainLog.Load().Error().Err(err).Msg("deAllocateIP failed")
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return err
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}
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return nil
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}
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// setDnsIgnoreUnusableInterface likes setDNS, but return a nil error if the interface is not usable.
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func setDnsIgnoreUnusableInterface(iface *net.Interface, nameservers []string) error {
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return setDNS(iface, nameservers)
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}
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// set the dns server for the provided network interface
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func setDNS(iface *net.Interface, nameservers []string) error {
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r, err := dns.NewOSConfigurator(logf, &health.Tracker{}, &controlknobs.Knobs{}, iface.Name)
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if err != nil {
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mainLog.Load().Error().Err(err).Msg("failed to create DNS OS configurator")
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return err
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}
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ns := make([]netip.Addr, 0, len(nameservers))
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for _, nameserver := range nameservers {
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ns = append(ns, netip.MustParseAddr(nameserver))
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}
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osConfig := dns.OSConfig{
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Nameservers: ns,
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SearchDomains: []dnsname.FQDN{},
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}
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if sds, err := searchDomains(); err == nil {
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osConfig.SearchDomains = sds
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} else {
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mainLog.Load().Debug().Err(err).Msg("failed to get search domains list")
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}
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if err := r.SetDNS(osConfig); err != nil {
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mainLog.Load().Error().Err(err).Msg("failed to set DNS")
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return err
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}
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return nil
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}
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// resetDnsIgnoreUnusableInterface likes resetDNS, but return a nil error if the interface is not usable.
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func resetDnsIgnoreUnusableInterface(iface *net.Interface) error {
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return resetDNS(iface)
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}
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// resetDNS resets DNS servers for the specified interface
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func resetDNS(iface *net.Interface) error {
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r, err := dns.NewOSConfigurator(logf, &health.Tracker{}, &controlknobs.Knobs{}, iface.Name)
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if err != nil {
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mainLog.Load().Error().Err(err).Msg("failed to create DNS OS configurator")
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return err
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}
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if err := r.Close(); err != nil {
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mainLog.Load().Error().Err(err).Msg("failed to rollback DNS setting")
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return err
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}
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return nil
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}
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// restoreDNS restores the DNS settings of the given interface.
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// this should only be executed upon turning off the ctrld service.
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func restoreDNS(iface *net.Interface) (err error) {
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return err
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}
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// currentDNS returns the current DNS servers for the specified interface
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func currentDNS(_ *net.Interface) []string {
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return ctrld.CurrentNameserversFromResolvconf()
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}
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// currentStaticDNS returns the current static DNS settings of given interface.
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func currentStaticDNS(iface *net.Interface) ([]string, error) {
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return currentDNS(iface), nil
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}
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