├── README.md
├── go.mod
└── main.go


/README.md:
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 1 | # h2i
 2 | 
 3 | Converts a list of hostnames or URLs to their corresponding IP address
 4 | 
 5 | 
 6 | ## Install
 7 | 
 8 | If you have Go installed and configured (i.e. with `$GOPATH/bin` in your `$PATH`):
 9 | 
10 | ```
11 | go install github.com/cybercdh/h2i@latest
12 | ```
13 | 
14 | ## Usage
15 | 
16 | ```
17 | $ h2i <url>
18 | ```
19 | or 
20 | ```
21 | $ cat <file> | h2i
22 | ```
23 | 
24 | By default, the code will simply print the list of IP's to the console. For more details, use the -v flag, per below.
25 | 
26 | ### Options
27 | 
28 | ```
29 | Usage of h2i:
30 |   -c int
31 |       set the concurrency level (default 20)
32 |   -dns string
33 |       Custom DNS server to use for resolution
34 |   -dns-tcp
35 |       Use DNS over TCP instead of the default UDP. Useful for SOCKS proxy environments where UDP is not supported.
36 |   -port string
37 |       DNS server port (default "53")
38 |   -v  Show hostname with the corresponding IP
39 |   -vv
40 |       Show any errors and relevant info
41 | ```


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/go.mod:
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1 | module github.com/cybercdh/h2i
2 | 
3 | go 1.19
4 | 


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/main.go:
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  1 | package main
  2 | 
  3 | import (
  4 | 	"bufio"
  5 | 	"context"
  6 | 	"flag"
  7 | 	"fmt"
  8 | 	"io"
  9 | 	"net"
 10 | 	"net/url"
 11 | 	"os"
 12 | 	"strings"
 13 | 	"sync"
 14 | )
 15 | 
 16 | func main() {
 17 | 	var concurrency int
 18 | 	var verbose, v_verbose, dnsTCP bool
 19 | 	var customDNS string
 20 | 	var dnsPort string
 21 | 
 22 | 	flag.IntVar(&concurrency, "c", 20, "set the concurrency level")
 23 | 	flag.BoolVar(&verbose, "v", false, "Show hostname with the corresponding IP")
 24 | 	flag.BoolVar(&v_verbose, "vv", false, "Show any errors and relevant info")
 25 | 	flag.StringVar(&customDNS, "dns", "", "Custom DNS server to use for resolution")
 26 | 	flag.StringVar(&dnsPort, "port", "53", "DNS server port")
 27 | 	flag.BoolVar(&dnsTCP, "dns-tcp", false, "Use DNS over TCP")
 28 | 	flag.Parse()
 29 | 
 30 | 	hosts := make(chan string)
 31 | 	var wg sync.WaitGroup
 32 | 	resolver := &net.Resolver{}
 33 | 
 34 | 	// Use custom DNS server if specified
 35 | 	if customDNS != "" {
 36 | 		resolver = &net.Resolver{
 37 | 			PreferGo: true,
 38 | 			Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
 39 | 			// Choose network type based on dnsTCP flag
 40 | 			networkType := "udp"
 41 | 			if dnsTCP {
 42 | 				networkType = "tcp"
 43 | 			}
 44 | 			return net.Dial(networkType, customDNS+":"+dnsPort)
 45 | 		},
 46 | 		}
 47 | 	}
 48 | 
 49 | 	for i := 0; i < concurrency; i++ {
 50 | 		wg.Add(1)
 51 | 
 52 | 		go func() {
 53 | 			for host := range hosts {
 54 | 				// Use custom resolver for lookup
 55 | 				addr, err := resolver.LookupIPAddr(context.Background(), host)
 56 | 				if err != nil {
 57 | 					if v_verbose {
 58 | 						fmt.Printf("%s could not be found\n", host)
 59 | 					}
 60 | 				} else {
 61 | 					if verbose {
 62 | 						fmt.Printf("%s,%s\n", host, addr[0].IP.String())
 63 | 					} else {
 64 | 						fmt.Println(addr[0].IP.String())
 65 | 					}
 66 | 				}
 67 | 			}
 68 | 			wg.Done()
 69 | 		}()
 70 | 	}
 71 | 
 72 | 	var input_hosts io.Reader = os.Stdin
 73 | 	arg_hosts := flag.Arg(0)
 74 | 	if arg_hosts != "" {
 75 | 		input_hosts = strings.NewReader(arg_hosts)
 76 | 	}
 77 | 
 78 | 	sc := bufio.NewScanner(input_hosts)
 79 | 	seen := make(map[string]bool)
 80 | 
 81 | 	for sc.Scan() {
 82 | 		tmp_host := sc.Text()
 83 | 		if strings.HasPrefix(tmp_host, "http") {
 84 | 			u, err := url.Parse(tmp_host)
 85 | 			if err != nil {
 86 | 				if v_verbose {
 87 | 					fmt.Printf("%s could not be parsed\n", tmp_host)
 88 | 				}
 89 | 				continue
 90 | 			}
 91 | 			tmp_host = u.Hostname()
 92 | 		}
 93 | 
 94 | 		if _, ok := seen[tmp_host]; ok {
 95 | 			if v_verbose {
 96 | 				fmt.Printf("Already seen %s\n", tmp_host)
 97 | 			}
 98 | 			continue
 99 | 		}
100 | 
101 | 		seen[tmp_host] = true
102 | 		hosts <- tmp_host
103 | 	}
104 | 
105 | 	close(hosts)
106 | 	if err := sc.Err(); err != nil {
107 | 		fmt.Fprintf(os.Stderr, "[!] failed to read input: %s\n", err)
108 | 	}
109 | 
110 | 	wg.Wait()
111 | }
112 | 


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