scratch/dns-server/main.go (view raw)
| 1 | package main |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | _ "embed" |
| 6 | "fmt" |
| 7 | "net" |
| 8 | ) |
| 9 | |
| 10 | func main() { |
| 11 | qname := "google.com" |
| 12 | server := "8.8.8.8:53" |
| 13 | |
| 14 | conn, _ := net.Dial("udp", server) |
| 15 | defer conn.Close() |
| 16 | |
| 17 | p := Packet{} |
| 18 | p.Header.ID = 6666 |
| 19 | p.Header.RecursionDesired = true |
| 20 | p.Questions = append(p.Questions, Question{ |
| 21 | Name: qname, |
| 22 | Type: 1, // A |
| 23 | Class: 1, // IN |
| 24 | }) |
| 25 | |
| 26 | buf := &bytes.Buffer{} |
| 27 | if err := p.Write(buf); err != nil { |
| 28 | fmt.Printf("failed to write packet: %v", err) |
| 29 | } |
| 30 | |
| 31 | if _, err := conn.Write(buf.Bytes()); err != nil { |
| 32 | fmt.Printf("failed to write to connection: %v", err) |
| 33 | } |
| 34 | |
| 35 | res := make([]byte, 512) |
| 36 | n, err := conn.Read(res) |
| 37 | if err != nil { |
| 38 | fmt.Printf("failed to read from connection: %v", err) |
| 39 | } |
| 40 | |
| 41 | resPack, err := ParsePacket(res[:n]) |
| 42 | if err != nil { |
| 43 | fmt.Printf("failed to parse packet: %v", err) |
| 44 | } |
| 45 | |
| 46 | fmt.Printf("%+v\n", resPack.Header) |
| 47 | for _, q := range resPack.Questions { |
| 48 | fmt.Printf("%+v\n", q) |
| 49 | } |
| 50 | for _, r := range resPack.Answers { |
| 51 | fmt.Printf("%+v\n", r) |
| 52 | } |
| 53 | for _, r := range resPack.Authorities { |
| 54 | fmt.Printf("%+v\n", r) |
| 55 | } |
| 56 | for _, r := range resPack.Resources { |
| 57 | fmt.Printf("%+v\n", r) |
| 58 | } |
| 59 | } |