package home import ( "bytes" "fmt" "io/ioutil" "net" "os" "os/exec" "runtime" "sort" "strings" "sync" "time" "github.com/AdguardTeam/AdGuardHome/dhcpd" "github.com/AdguardTeam/AdGuardHome/dnsforward" "github.com/AdguardTeam/dnsproxy/upstream" "github.com/AdguardTeam/golibs/log" "github.com/AdguardTeam/golibs/utils" ) const ( clientsUpdatePeriod = 1 * time.Hour ) // Client information type Client struct { IDs []string Tags []string Name string UseOwnSettings bool // false: use global settings FilteringEnabled bool SafeSearchEnabled bool SafeBrowsingEnabled bool ParentalEnabled bool UseOwnBlockedServices bool // false: use global settings BlockedServices []string Upstreams []string // list of upstream servers to be used for the client's requests // Upstream objects: // nil: not yet initialized // not nil, but empty: initialized, no good upstreams // not nil, not empty: Upstreams ready to be used upstreamObjects []upstream.Upstream } type clientSource uint // Client sources const ( // Priority: etc/hosts > DHCP > ARP > rDNS > WHOIS ClientSourceWHOIS clientSource = iota // from WHOIS ClientSourceRDNS // from rDNS ClientSourceDHCP // from DHCP ClientSourceARP // from 'arp -a' ClientSourceHostsFile // from /etc/hosts ) // ClientHost information type ClientHost struct { Host string Source clientSource WhoisInfo [][]string // [[key,value], ...] } type clientsContainer struct { list map[string]*Client // name -> client idIndex map[string]*Client // IP -> client ipHost map[string]*ClientHost // IP -> Hostname lock sync.Mutex allTags map[string]bool // dhcpServer is used for looking up clients IP addresses by MAC addresses dhcpServer *dhcpd.Server testing bool // if TRUE, this object is used for internal tests } // Init initializes clients container // Note: this function must be called only once func (clients *clientsContainer) Init(objects []clientObject, dhcpServer *dhcpd.Server) { if clients.list != nil { log.Fatal("clients.list != nil") } clients.list = make(map[string]*Client) clients.idIndex = make(map[string]*Client) clients.ipHost = make(map[string]*ClientHost) clients.allTags = make(map[string]bool) for _, t := range clientTags { clients.allTags[t] = false } clients.dhcpServer = dhcpServer clients.addFromConfig(objects) if !clients.testing { go clients.periodicUpdate() clients.addFromDHCP() clients.dhcpServer.SetOnLeaseChanged(clients.onDHCPLeaseChanged) clients.registerWebHandlers() } } type clientObject struct { Name string `yaml:"name"` Tags []string `yaml:"tags"` IDs []string `yaml:"ids"` UseGlobalSettings bool `yaml:"use_global_settings"` FilteringEnabled bool `yaml:"filtering_enabled"` ParentalEnabled bool `yaml:"parental_enabled"` SafeSearchEnabled bool `yaml:"safesearch_enabled"` SafeBrowsingEnabled bool `yaml:"safebrowsing_enabled"` UseGlobalBlockedServices bool `yaml:"use_global_blocked_services"` BlockedServices []string `yaml:"blocked_services"` Upstreams []string `yaml:"upstreams"` } func (clients *clientsContainer) tagKnown(tag string) bool { _, ok := clients.allTags[tag] return ok } func (clients *clientsContainer) addFromConfig(objects []clientObject) { for _, cy := range objects { cli := Client{ Name: cy.Name, IDs: cy.IDs, UseOwnSettings: !cy.UseGlobalSettings, FilteringEnabled: cy.FilteringEnabled, ParentalEnabled: cy.ParentalEnabled, SafeSearchEnabled: cy.SafeSearchEnabled, SafeBrowsingEnabled: cy.SafeBrowsingEnabled, UseOwnBlockedServices: !cy.UseGlobalBlockedServices, BlockedServices: cy.BlockedServices, Upstreams: cy.Upstreams, } for _, t := range cy.Tags { if !clients.tagKnown(t) { log.Debug("Clients: skipping unknown tag '%s'", t) continue } cli.Tags = append(cli.Tags, t) } sort.Strings(cli.Tags) _, err := clients.Add(cli) if err != nil { log.Tracef("clientAdd: %s", err) } } } // WriteDiskConfig - write configuration func (clients *clientsContainer) WriteDiskConfig(objects *[]clientObject) { clients.lock.Lock() for _, cli := range clients.list { cy := clientObject{ Name: cli.Name, UseGlobalSettings: !cli.UseOwnSettings, FilteringEnabled: cli.FilteringEnabled, ParentalEnabled: cli.ParentalEnabled, SafeSearchEnabled: cli.SafeSearchEnabled, SafeBrowsingEnabled: cli.SafeBrowsingEnabled, UseGlobalBlockedServices: !cli.UseOwnBlockedServices, } cy.Tags = stringArrayDup(cli.Tags) cy.IDs = stringArrayDup(cli.IDs) cy.BlockedServices = stringArrayDup(cli.BlockedServices) cy.Upstreams = stringArrayDup(cli.Upstreams) *objects = append(*objects, cy) } clients.lock.Unlock() } func (clients *clientsContainer) periodicUpdate() { for { clients.addFromHostsFile() clients.addFromSystemARP() time.Sleep(clientsUpdatePeriod) } } func (clients *clientsContainer) onDHCPLeaseChanged(flags int) { switch flags { case dhcpd.LeaseChangedAdded, dhcpd.LeaseChangedAddedStatic, dhcpd.LeaseChangedRemovedStatic: clients.addFromDHCP() } } // Exists checks if client with this IP already exists func (clients *clientsContainer) Exists(ip string, source clientSource) bool { clients.lock.Lock() defer clients.lock.Unlock() _, ok := clients.findByIP(ip) if ok { return true } ch, ok := clients.ipHost[ip] if !ok { return false } if source > ch.Source { return false // we're going to overwrite this client's info with a stronger source } return true } func stringArrayDup(a []string) []string { a2 := make([]string, len(a)) copy(a2, a) return a2 } // Find searches for a client by IP func (clients *clientsContainer) Find(ip string) (Client, bool) { clients.lock.Lock() defer clients.lock.Unlock() c, ok := clients.findByIP(ip) if !ok { return Client{}, false } c.IDs = stringArrayDup(c.IDs) c.Tags = stringArrayDup(c.Tags) c.BlockedServices = stringArrayDup(c.BlockedServices) c.Upstreams = stringArrayDup(c.Upstreams) return c, true } func upstreamArrayCopy(a []upstream.Upstream) []upstream.Upstream { a2 := make([]upstream.Upstream, len(a)) copy(a2, a) return a2 } // FindUpstreams looks for upstreams configured for the client // If no client found for this IP, or if no custom upstreams are configured, // this method returns nil func (clients *clientsContainer) FindUpstreams(ip string) []upstream.Upstream { clients.lock.Lock() defer clients.lock.Unlock() c, ok := clients.findByIP(ip) if !ok { return nil } if c.upstreamObjects == nil { c.upstreamObjects = make([]upstream.Upstream, 0) for _, us := range c.Upstreams { u, err := upstream.AddressToUpstream(us, upstream.Options{Timeout: dnsforward.DefaultTimeout}) if err != nil { log.Error("upstream.AddressToUpstream: %s: %s", us, err) continue } c.upstreamObjects = append(c.upstreamObjects, u) } } if len(c.upstreamObjects) == 0 { return nil } return upstreamArrayCopy(c.upstreamObjects) } // Find searches for a client by IP (and does not lock anything) func (clients *clientsContainer) findByIP(ip string) (Client, bool) { ipAddr := net.ParseIP(ip) if ipAddr == nil { return Client{}, false } c, ok := clients.idIndex[ip] if ok { return *c, true } for _, c = range clients.list { for _, id := range c.IDs { _, ipnet, err := net.ParseCIDR(id) if err != nil { continue } if ipnet.Contains(ipAddr) { return *c, true } } } if clients.dhcpServer == nil { return Client{}, false } macFound := clients.dhcpServer.FindMACbyIP(ipAddr) if macFound == nil { return Client{}, false } for _, c = range clients.list { for _, id := range c.IDs { hwAddr, err := net.ParseMAC(id) if err != nil { continue } if bytes.Equal(hwAddr, macFound) { return *c, true } } } return Client{}, false } // FindAutoClient - search for an auto-client by IP func (clients *clientsContainer) FindAutoClient(ip string) (ClientHost, bool) { ipAddr := net.ParseIP(ip) if ipAddr == nil { return ClientHost{}, false } clients.lock.Lock() defer clients.lock.Unlock() ch, ok := clients.ipHost[ip] if ok { return *ch, true } return ClientHost{}, false } // Check if Client object's fields are correct func (clients *clientsContainer) check(c *Client) error { if len(c.Name) == 0 { return fmt.Errorf("Invalid Name") } if len(c.IDs) == 0 { return fmt.Errorf("ID required") } for i, id := range c.IDs { ip := net.ParseIP(id) if ip != nil { c.IDs[i] = ip.String() // normalize IP address continue } _, _, err := net.ParseCIDR(id) if err == nil { continue } _, err = net.ParseMAC(id) if err == nil { continue } return fmt.Errorf("Invalid ID: %s", id) } for _, t := range c.Tags { if !clients.tagKnown(t) { return fmt.Errorf("Invalid tag: %s", t) } } sort.Strings(c.Tags) if len(c.Upstreams) != 0 { err := dnsforward.ValidateUpstreams(c.Upstreams) if err != nil { return fmt.Errorf("Invalid upstream servers: %s", err) } } return nil } // Add a new client object // Return true: success; false: client exists. func (clients *clientsContainer) Add(c Client) (bool, error) { e := clients.check(&c) if e != nil { return false, e } clients.lock.Lock() defer clients.lock.Unlock() // check Name index _, ok := clients.list[c.Name] if ok { return false, nil } // check ID index for _, id := range c.IDs { c2, ok := clients.idIndex[id] if ok { return false, fmt.Errorf("Another client uses the same ID (%s): %s", id, c2.Name) } } // update Name index clients.list[c.Name] = &c // update ID index for _, id := range c.IDs { clients.idIndex[id] = &c } log.Debug("Clients: added '%s': ID:%v [%d]", c.Name, c.IDs, len(clients.list)) return true, nil } // Del removes a client func (clients *clientsContainer) Del(name string) bool { clients.lock.Lock() defer clients.lock.Unlock() c, ok := clients.list[name] if !ok { return false } // update Name index delete(clients.list, name) // update ID index for _, id := range c.IDs { delete(clients.idIndex, id) } return true } // Return TRUE if arrays are equal func arraysEqual(a, b []string) bool { if len(a) != len(b) { return false } for i := 0; i != len(a); i++ { if a[i] != b[i] { return false } } return true } // Update a client func (clients *clientsContainer) Update(name string, c Client) error { err := clients.check(&c) if err != nil { return err } clients.lock.Lock() defer clients.lock.Unlock() old, ok := clients.list[name] if !ok { return fmt.Errorf("Client not found") } // check Name index if old.Name != c.Name { _, ok = clients.list[c.Name] if ok { return fmt.Errorf("Client already exists") } } // check IP index if !arraysEqual(old.IDs, c.IDs) { for _, id := range c.IDs { c2, ok := clients.idIndex[id] if ok && c2 != old { return fmt.Errorf("Another client uses the same ID (%s): %s", id, c2.Name) } } // update ID index for _, id := range old.IDs { delete(clients.idIndex, id) } for _, id := range c.IDs { clients.idIndex[id] = old } } // update Name index if old.Name != c.Name { delete(clients.list, old.Name) clients.list[c.Name] = old } // update upstreams cache c.upstreamObjects = nil *old = c return nil } // SetWhoisInfo - associate WHOIS information with a client func (clients *clientsContainer) SetWhoisInfo(ip string, info [][]string) { clients.lock.Lock() defer clients.lock.Unlock() _, ok := clients.findByIP(ip) if ok { log.Debug("Clients: client for %s is already created, ignore WHOIS info", ip) return } ch, ok := clients.ipHost[ip] if ok { ch.WhoisInfo = info log.Debug("Clients: set WHOIS info for auto-client %s: %v", ch.Host, ch.WhoisInfo) return } // Create a ClientHost implicitly so that we don't do this check again ch = &ClientHost{ Source: ClientSourceWHOIS, } ch.WhoisInfo = info clients.ipHost[ip] = ch log.Debug("Clients: set WHOIS info for auto-client with IP %s: %v", ip, ch.WhoisInfo) } // AddHost adds new IP -> Host pair // Use priority of the source (etc/hosts > ARP > rDNS) // so we overwrite existing entries with an equal or higher priority func (clients *clientsContainer) AddHost(ip, host string, source clientSource) (bool, error) { clients.lock.Lock() b, e := clients.addHost(ip, host, source) clients.lock.Unlock() return b, e } func (clients *clientsContainer) addHost(ip, host string, source clientSource) (bool, error) { // check auto-clients index ch, ok := clients.ipHost[ip] if ok && ch.Source > source { return false, nil } else if ok { ch.Source = source } else { ch = &ClientHost{ Host: host, Source: source, } clients.ipHost[ip] = ch } log.Debug("Clients: added '%s' -> '%s' [%d]", ip, host, len(clients.ipHost)) return true, nil } // Remove all entries that match the specified source func (clients *clientsContainer) rmHosts(source clientSource) int { n := 0 for k, v := range clients.ipHost { if v.Source == source { delete(clients.ipHost, k) n++ } } log.Debug("Clients: removed %d client aliases", n) return n } // Parse system 'hosts' file and fill clients array func (clients *clientsContainer) addFromHostsFile() { hostsFn := "/etc/hosts" if runtime.GOOS == "windows" { hostsFn = os.ExpandEnv("$SystemRoot\\system32\\drivers\\etc\\hosts") } d, e := ioutil.ReadFile(hostsFn) if e != nil { log.Info("Can't read file %s: %v", hostsFn, e) return } clients.lock.Lock() defer clients.lock.Unlock() _ = clients.rmHosts(ClientSourceHostsFile) lines := strings.Split(string(d), "\n") n := 0 for _, ln := range lines { ln = strings.TrimSpace(ln) if len(ln) == 0 || ln[0] == '#' { continue } fields := strings.Fields(ln) if len(fields) < 2 { continue } ok, e := clients.addHost(fields[0], fields[1], ClientSourceHostsFile) if e != nil { log.Tracef("%s", e) } if ok { n++ } } log.Debug("Clients: added %d client aliases from %s", n, hostsFn) } // Add IP -> Host pairs from the system's `arp -a` command output // The command's output is: // HOST (IP) at MAC on IFACE func (clients *clientsContainer) addFromSystemARP() { if runtime.GOOS == "windows" { return } cmd := exec.Command("arp", "-a") log.Tracef("executing %s %v", cmd.Path, cmd.Args) data, err := cmd.Output() if err != nil || cmd.ProcessState.ExitCode() != 0 { log.Debug("command %s has failed: %v code:%d", cmd.Path, err, cmd.ProcessState.ExitCode()) return } clients.lock.Lock() defer clients.lock.Unlock() _ = clients.rmHosts(ClientSourceARP) n := 0 lines := strings.Split(string(data), "\n") for _, ln := range lines { open := strings.Index(ln, " (") close := strings.Index(ln, ") ") if open == -1 || close == -1 || open >= close { continue } host := ln[:open] ip := ln[open+2 : close] if utils.IsValidHostname(host) != nil || net.ParseIP(ip) == nil { continue } ok, e := clients.addHost(ip, host, ClientSourceARP) if e != nil { log.Tracef("%s", e) } if ok { n++ } } log.Debug("Clients: added %d client aliases from 'arp -a' command output", n) } // Add clients from DHCP that have non-empty Hostname property func (clients *clientsContainer) addFromDHCP() { if clients.dhcpServer == nil { return } clients.lock.Lock() defer clients.lock.Unlock() _ = clients.rmHosts(ClientSourceDHCP) leases := clients.dhcpServer.Leases(dhcpd.LeasesAll) n := 0 for _, l := range leases { if len(l.Hostname) == 0 { continue } ok, _ := clients.addHost(l.IP.String(), l.Hostname, ClientSourceDHCP) if ok { n++ } } log.Debug("Clients: added %d client aliases from DHCP", n) }