Make everything more readable (#2)

1. I made JSON print indented instead of inline
2. I created a util package and moved `ReverseDNS` and `ResolveHTTPS` there
3. I created a new struct called Answers where all variables for the output live now, and adjusted the response struct to have the Answers struct in it. This lets us reuse the struct more instead of having variables floating around, lets us make the response more custom, offers more understandable code reuse, and makes things (I think) more readable.

Aside: you will notice the struct has little json defs. This is because struct values encode as JSON objects and can preserve the output name this way

Most of this just makes expanding on awl easier in the future.

Co-authored-by: grumbulon <grumbulon@dismail.de>
Reviewed-on: sam/awl#2
Co-authored-by: grumbulon <grumbulon@grumbulon.xyz>
Co-committed-by: grumbulon <grumbulon@grumbulon.xyz>
This commit is contained in:
grumbulon 2022-06-22 11:55:38 +00:00 committed by Sam
parent 50d7b9dc2a
commit 9b979667d6
4 changed files with 133 additions and 126 deletions

146
awl.go
View file

@ -1,32 +1,21 @@
package main
import (
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"io"
"net"
"net/http"
"os"
"runtime"
"strconv"
"strings"
"time"
"github.com/c-robinson/iplib"
"git.froth.zone/sam/awl/util"
"github.com/miekg/dns"
"github.com/urfave/cli/v2"
"golang.org/x/net/idna"
)
// The basic structure of a DNS request
type request struct {
server string // The server to make the DNS request from
request uint16 // The type of request
name string // The domain name to make a DNS request for
}
func main() {
// Custom version string
cli.VersionPrinter = func(c *cli.Context) {
@ -126,8 +115,8 @@ func main() {
},
Action: func(c *cli.Context) error {
var err error
req := parseArgs(c.Args().Slice())
var resp util.Response
resp.Answers = parseArgs(c.Args().Slice())
// Set DNS-over-TLS, if enabled
port := c.Int("port")
@ -141,29 +130,26 @@ func main() {
}
if !c.Bool("https") {
req.server = net.JoinHostPort(req.server, strconv.Itoa(port))
resp.Answers.Server = net.JoinHostPort(resp.Answers.Server, strconv.Itoa(port))
} else {
req.server = "https://" + req.server
resp.Answers.Server = "https://" + resp.Answers.Server
}
// Process the IP/Phone number so a PTR/NAPTR can be done
if c.Bool("reverse") {
if dns.TypeToString[req.request] == "A" {
req.request = dns.StringToType["PTR"]
}
req.name, err = reverseDNS(req.name, dns.TypeToString[req.request])
if err != nil {
return err
if dns.TypeToString[resp.Answers.Request] == "A" {
resp.Answers.Request = dns.StringToType["PTR"]
}
resp.Answers.Name, err = util.ReverseDNS(resp.Answers.Name, dns.TypeToString[resp.Answers.Request])
}
// if the domain is not canonical, make it canonical
if !strings.HasSuffix(req.name, ".") {
req.name = fmt.Sprintf("%s.", req.name)
if !strings.HasSuffix(resp.Answers.Name, ".") {
resp.Answers.Name = fmt.Sprintf("%s.", resp.Answers.Name)
}
msg := new(dns.Msg)
msg.SetQuestion(req.name, req.request)
msg.SetQuestion(resp.Answers.Name, resp.Answers.Request)
// Set DNSSEC if requested
if c.Bool("dnssec") {
@ -171,13 +157,12 @@ func main() {
}
var (
in *dns.Msg
rtt time.Duration
in *dns.Msg
)
// Make the DNS request
if c.Bool("https") {
in, err = resolveHTTPS(msg, req.server)
in, err = util.ResolveHTTPS(msg, resp.Answers.Server)
} else if c.Bool("quic") {
return fmt.Errorf("quic: not yet implemented")
} else {
@ -208,7 +193,7 @@ func main() {
if c.Bool("tls") {
d.Net = "tcp-tls"
}
in, rtt, err = d.Exchange(msg, req.server)
in, resp.Answers.RTT, err = d.Exchange(msg, resp.Answers.Server)
// If UDP truncates, use TCP instead
if !c.Bool("no-truncate") {
@ -221,7 +206,7 @@ func main() {
if c.Bool("6") {
d.Net = "tcp6"
}
in, rtt, err = d.Exchange(msg, req.server)
in, resp.Answers.RTT, err = d.Exchange(msg, resp.Answers.Server)
}
}
}
@ -231,14 +216,14 @@ func main() {
}
if c.Bool("json") {
json, _ := json.Marshal(in)
json, _ := json.MarshalIndent(in, "", " ")
fmt.Println(string(json))
} else {
if !c.Bool("short") {
// Print everything
fmt.Println(in)
fmt.Println(";; Query time:", rtt)
fmt.Println(";; SERVER:", req.server)
fmt.Println(";; Query time:", resp.Answers.RTT)
fmt.Println(";; SERVER:", resp.Answers.Server)
fmt.Println(";; WHEN:", time.Now().Format(time.RFC1123))
fmt.Println(";; MSG SIZE rcvd:", in.Len())
} else {
@ -261,114 +246,51 @@ func main() {
}
}
func parseArgs(args []string) request {
func parseArgs(args []string) util.Answers {
var (
server string
req uint16
name string
resp util.Response
)
for _, arg := range args {
// If it starts with @, it's a DNS server
if strings.HasPrefix(arg, "@") {
server = strings.Split(arg, "@")[1]
resp.Answers.Server = strings.Split(arg, "@")[1]
continue
}
// If there's a dot, it's a name
if strings.Contains(arg, ".") {
name, _ = idna.ToUnicode(arg)
resp.Answers.Name, _ = idna.ToUnicode(arg)
continue
}
// If it's a request, it's a request (duh)
if r, ok := dns.StringToType[strings.ToUpper(arg)]; ok {
req = r
resp.Answers.Request = r
continue
}
//else, assume it's a name
name, _ = idna.ToUnicode(arg)
resp.Answers.Name, _ = idna.ToUnicode(arg)
}
// If nothing was set, set a default
if name == "" {
name = "."
if req == 0 {
req = dns.StringToType["NS"]
if resp.Answers.Name == "" {
resp.Answers.Name = "."
if resp.Answers.Request == 0 {
resp.Answers.Request = dns.StringToType["NS"]
}
} else {
if req == 0 {
req = dns.StringToType["A"]
if resp.Answers.Request == 0 {
resp.Answers.Request = dns.StringToType["A"]
}
}
if server == "" {
if resp.Answers.Server == "" {
resolv, err := dns.ClientConfigFromFile("/etc/resolv.conf")
if err != nil { // Query Google by default, needed for Windows since the DNS library doesn't support Windows
// TODO: Actually find where windows stuffs its dns resolvers
server = "8.8.4.4"
resp.Answers.Server = "8.8.4.4"
} else {
server = resolv.Servers[0]
resp.Answers.Server = resolv.Servers[0]
}
}
return request{server: server, request: req, name: name}
}
func reverseDNS(dom string, q string) (string, error) {
if q == "PTR" {
if strings.Contains(dom, ".") {
// It's an IPv4 address
ip := net.ParseIP(dom)
if ip != nil {
return iplib.IP4ToARPA(ip), nil
} else {
return "", errors.New("error: Could not parse IPv4 address")
}
} else if strings.Contains(dom, ":") {
// It's an IPv6 address
ip := net.ParseIP(dom)
if ip != nil {
return iplib.IP6ToARPA(ip), nil
} else {
return "", errors.New("error: Could not parse IPv6 address")
}
}
}
return "", errors.New("error: -x flag given but no IP found")
}
func resolveHTTPS(msg *dns.Msg, server string) (*dns.Msg, error) {
httpR := &http.Client{}
buf, err := msg.Pack()
if err != nil {
return nil, err
}
query := server + "?dns=" + base64.RawURLEncoding.EncodeToString(buf)
req, err := http.NewRequest("GET", query, nil)
if err != nil {
return nil, err
}
req.Header.Set("Accept", "application/dns-message")
res, err := httpR.Do(req)
if err != nil {
return nil, err
}
defer res.Body.Close()
if res.StatusCode != http.StatusOK {
return nil, fmt.Errorf("bad HTTP Request: %d", res.StatusCode)
}
fullRes, err := io.ReadAll(res.Body)
if err != nil {
return nil, err
}
response := dns.Msg{}
err = response.Unpack(fullRes)
if err != nil {
return nil, err
}
return &response, nil
return util.Answers{Server: resp.Answers.Server, Request: resp.Answers.Request, Name: resp.Answers.Name}
}

9
go.mod
View file

@ -1,4 +1,4 @@
module example.com/awl
module git.froth.zone/sam/awl
go 1.18
@ -13,8 +13,9 @@ require (
github.com/cpuguy83/go-md2man/v2 v2.0.2 // indirect
github.com/russross/blackfriday/v2 v2.1.0 // indirect
github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 // indirect
golang.org/x/sys v0.0.0-20220615213510-4f61da869c0c // indirect
golang.org/x/mod v0.4.2 // indirect
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a // indirect
golang.org/x/text v0.3.7 // indirect
golang.org/x/tools v0.1.11 // indirect
golang.org/x/tools v0.1.6-0.20210726203631-07bc1bf47fb2 // indirect
golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
)

15
go.sum
View file

@ -2,8 +2,6 @@ github.com/c-robinson/iplib v1.0.3 h1:NG0UF0GoEsrC1/vyfX1Lx2Ss7CySWl3KqqXh3q4DdP
github.com/c-robinson/iplib v1.0.3/go.mod h1:i3LuuFL1hRT5gFpBRnEydzw8R6yhGkF4szNDIbF8pgo=
github.com/cpuguy83/go-md2man/v2 v2.0.2 h1:p1EgwI/C7NhT0JmVkwCD2ZBK8j4aeHQX2pMHHBfMQ6w=
github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
github.com/miekg/dns v1.1.49 h1:qe0mQU3Z/XpFeE+AEBo2rqaS1IPBJ3anmqZ4XiZJVG8=
github.com/miekg/dns v1.1.49/go.mod h1:e3IlAVfNqAllflbibAZEWOXOQ+Ynzk/dDozDxY7XnME=
github.com/miekg/dns v1.1.50 h1:DQUfb9uc6smULcREF09Uc+/Gd46YWqJd5DbpPE9xkcA=
github.com/miekg/dns v1.1.50/go.mod h1:e3IlAVfNqAllflbibAZEWOXOQ+Ynzk/dDozDxY7XnME=
github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
@ -15,15 +13,12 @@ github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673/go.mod h1:N3UwUGtsr
github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
golang.org/x/mod v0.4.2 h1:Gz96sIWK3OalVv/I/qNygP42zyoKp3xptRVCWRFEBvo=
golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 h1:6zppjxzCulZykYSLyVDYbneBfbaBIQPYMevg0bEwv2s=
golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
golang.org/x/net v0.0.0-20210726213435-c6fcb2dbf985/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
golang.org/x/net v0.0.0-20220617184016-355a448f1bc9 h1:Yqz/iviulwKwAREEeUd3nbBFn0XuyJqkoft2IlrvOhc=
golang.org/x/net v0.0.0-20220617184016-355a448f1bc9/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
golang.org/x/net v0.0.0-20220621193019-9d032be2e588 h1:9ubFuySsnAJYGyJrZ3koiEv8FyqofCBdz3G9Mbf2YFc=
golang.org/x/net v0.0.0-20220621193019-9d032be2e588/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@ -36,8 +31,8 @@ golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7w
golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220615213510-4f61da869c0c h1:aFV+BgZ4svzjfabn8ERpuB4JI4N6/rdy1iusx77G3oU=
golang.org/x/sys v0.0.0-20220615213510-4f61da869c0c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a h1:dGzPydgVsqGcTRVwiLJ1jVbufYwmzD3LfVPLKsKg+0k=
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
@ -46,9 +41,9 @@ golang.org/x/text v0.3.7 h1:olpwvP2KacW1ZWvsR7uQhoyTYvKAupfQrRGBFM352Gk=
golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
golang.org/x/tools v0.1.6-0.20210726203631-07bc1bf47fb2 h1:BonxutuHCTL0rBDnZlKjpGIQFTjyUVTexFOdWkB6Fg0=
golang.org/x/tools v0.1.6-0.20210726203631-07bc1bf47fb2/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
golang.org/x/tools v0.1.11 h1:loJ25fNOEhSXfHrpoGj91eCUThwdNX6u24rO1xnNteY=
golang.org/x/tools v0.1.11/go.mod h1:SgwaegtQh8clINPpECJMqnxLv9I09HLqnW3RMqW0CA4=
golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

89
util/dns.go Normal file
View file

@ -0,0 +1,89 @@
package util
import (
"encoding/base64"
"errors"
"fmt"
"io"
"net"
"net/http"
"strings"
"time"
"github.com/c-robinson/iplib"
"github.com/miekg/dns"
)
type Response struct {
Answers Answers `json:"Response"` //
}
// The Answers struct is the basic structure of a DNS request
// to be returned to the user upon making a request
type Answers struct {
Server string `json:"Server"` // The server to make the DNS request from
Request uint16 `json:"Request"` // The type of request
Name string `json:"Name"` // The domain name to make a DNS request for
RTT time.Duration `json:"RTT"` // When AWL was ran
}
func ReverseDNS(dom string, q string) (string, error) {
if q == "PTR" {
if strings.Contains(dom, ".") {
// It's an IPv4 address
ip := net.ParseIP(dom)
if ip != nil {
return iplib.IP4ToARPA(ip), nil
} else {
return "", errors.New("error: Could not parse IPv4 address")
}
} else if strings.Contains(dom, ":") {
// It's an IPv6 address
ip := net.ParseIP(dom)
if ip != nil {
return iplib.IP6ToARPA(ip), nil
} else {
return "", errors.New("error: Could not parse IPv6 address")
}
}
}
return "", errors.New("error: -x flag given but no IP found")
}
func ResolveHTTPS(msg *dns.Msg, server string) (*dns.Msg, error) {
httpR := &http.Client{}
buf, err := msg.Pack()
if err != nil {
return nil, err
}
query := server + "?dns=" + base64.RawURLEncoding.EncodeToString(buf)
req, err := http.NewRequest("GET", query, nil)
if err != nil {
return nil, err
}
req.Header.Set("Accept", "application/dns-message")
res, err := httpR.Do(req)
if err != nil {
return nil, err
}
defer res.Body.Close()
if res.StatusCode != http.StatusOK {
return nil, fmt.Errorf("bad HTTP Request: %d", res.StatusCode)
}
fullRes, err := io.ReadAll(res.Body)
if err != nil {
return nil, err
}
response := dns.Msg{}
err = response.Unpack(fullRes)
if err != nil {
return nil, err
}
return &response, nil
}