package cmds import ( "bufio" "bytes" "fmt" "net" "os/exec" "regexp" "strconv" "strings" "time" "github.com/go-errors/errors" "git.gensokyo.cafe/kkyy/tgbot_misaka_5882f7/utils" ) var ( // According to wikipedia digValidDnsTypes = utils.ToLookupMap([]string{ "A", "AAAA", "AFSDB", "APL", "CAA", "CDNSKEY", "CDS", "CERT", "CNAME", "CSYNC", "DHCID", "DLV", "DNAME", "DNSKEY", "DS", "EUI48", "EUI64", "HINFO", "HIP", "HTTPS", "IPSECKEY", "KEY", "KX", "LOC", "MX", "NAPTR", "NS", "NSEC", "NSEC3", "NSEC3PARAM", "OPENPGPKEY", "PTR", "RRSIG", "RP", "SIG", "SMIMEA", "SOA", "SRV", "SSHFP", "SVCB", "TA", "TKEY", "TLSA", "TSIG", "TXT", "URI", "ZONEMD", }) digErrInvalidArgs = fmt.Errorf("invalid request") digDnsNameRe = regexp.MustCompile(`^([a-z0-9_-]+\.?)+|\.$`) ) type DigRequest struct { Name string Type string Reverse bool } func NewDigRequest(req string) (*DigRequest, error) { ret := &DigRequest{} args := strings.Fields(req) nArgs := len(args) if nArgs == 0 || nArgs > 2 { return nil, digErrInvalidArgs } if nArgs > 1 { typ := strings.ToUpper(args[1]) if _, ok := digValidDnsTypes[typ]; !ok { return nil, digErrInvalidArgs } ret.Type = typ } ip := net.ParseIP(args[0]) if ip != nil { ret.Name = ip.String() ret.Reverse = true ret.Type = "" return ret, nil } name := strings.ToLower(args[0]) if !digDnsNameRe.Match([]byte(name)) { return nil, digErrInvalidArgs } ret.Name = name return ret, nil } func (r *DigRequest) ToCmdArgs() []string { args := make([]string, 0, 4) args = append(args, "-u") if r.Reverse { args = append(args, "-x") } args = append(args, r.Name) if r.Type != "" { args = append(args, r.Type) } return args } type DigDnsRecord struct { Name string TTL int Class string Type string Data string } type DigResponse struct { Status string QueryTime time.Duration Records []DigDnsRecord } var ( digRespDnsRecordLineRe = regexp.MustCompile(`^([^;\s]\S*)\s+(\d+)\s+([A-Z]+)\s+([A-Z]+)\s+(.*)$`) digRespHeaderLineRe = regexp.MustCompile(`^;;.*HEADER.*status: ([A-Z]+),.*$`) digResqQueryTimeLineRe = regexp.MustCompile(`^;; Query time: (\d+) usec$`) ) func buildDigResponse(buf []byte) (*DigResponse, error) { sc := bufio.NewScanner(bytes.NewReader(buf)) ret := &DigResponse{} for sc.Scan() { line := sc.Text() if line == "" { continue } if line[0] == ';' { if ret.Status == "" { m := digRespHeaderLineRe.FindStringSubmatch(line) if len(m) == 2 { ret.Status = m[1] continue } } m := digResqQueryTimeLineRe.FindStringSubmatch(line) if len(m) == 2 { usec, err := strconv.ParseInt(m[1], 10, 64) if err != nil { return nil, errors.WrapPrefix(err, "failed to parse query time", 0) } ret.QueryTime = time.Microsecond * time.Duration(usec) continue } } m := digRespDnsRecordLineRe.FindStringSubmatch(line) if len(m) == 6 { ttl, err := strconv.Atoi(m[2]) if err != nil { return nil, errors.WrapPrefix(err, "failed to parse ttl", 0) } ret.Records = append(ret.Records, DigDnsRecord{ Name: m[1], TTL: ttl, Class: m[3], Type: m[4], Data: m[5], }) } } if ret.Status == "" { return nil, errors.New("failed to parse response: \"status\" is unknown") } return ret, nil } func Dig(req *DigRequest) (*DigResponse, error) { cmd := exec.Command("/usr/bin/dig", req.ToCmdArgs()...) cmd.Stdin = nil buf, err := cmd.Output() if err != nil { return nil, errors.WrapPrefix(err, "failed to run dig command", 0) } ret, err := buildDigResponse(buf) if err != nil { return nil, errors.WrapPrefix(err, "failed to parse dig response", 0) } return ret, nil }