github.com/xxf098/lite-proxy@v0.15.1-0.20230422081941-12c69f323218/dns/util.go (about)

     1  package dns
     2  
     3  import (
     4  	"crypto/tls"
     5  	"net"
     6  	"time"
     7  
     8  	D "github.com/miekg/dns"
     9  	"github.com/xxf098/lite-proxy/common/cache"
    10  )
    11  
    12  func putMsgToCache(c *cache.LruCache, key string, msg *D.Msg) {
    13  	var ttl uint32
    14  	switch {
    15  	case len(msg.Answer) != 0:
    16  		ttl = msg.Answer[0].Header().Ttl
    17  	case len(msg.Ns) != 0:
    18  		ttl = msg.Ns[0].Header().Ttl
    19  	case len(msg.Extra) != 0:
    20  		ttl = msg.Extra[0].Header().Ttl
    21  	default:
    22  		// log.D("[DNS] response msg empty: %#v", msg)
    23  		return
    24  	}
    25  
    26  	c.SetWithExpire(key, msg.Copy(), time.Now().Add(time.Second*time.Duration(ttl)))
    27  }
    28  
    29  func setMsgTTL(msg *D.Msg, ttl uint32) {
    30  	for _, answer := range msg.Answer {
    31  		answer.Header().Ttl = ttl
    32  	}
    33  
    34  	for _, ns := range msg.Ns {
    35  		ns.Header().Ttl = ttl
    36  	}
    37  
    38  	for _, extra := range msg.Extra {
    39  		extra.Header().Ttl = ttl
    40  	}
    41  }
    42  
    43  func isIPRequest(q D.Question) bool {
    44  	return q.Qclass == D.ClassINET && (q.Qtype == D.TypeA || q.Qtype == D.TypeAAAA)
    45  }
    46  
    47  func transform(servers []NameServer, resolver *Resolver) []dnsClient {
    48  	ret := []dnsClient{}
    49  	for _, s := range servers {
    50  		// if s.Net == "https" {
    51  		// 	ret = append(ret, newDoHClient(s.Addr, resolver))
    52  		// 	continue
    53  		// }
    54  
    55  		host, port, _ := net.SplitHostPort(s.Addr)
    56  		ret = append(ret, &client{
    57  			Client: &D.Client{
    58  				Net: s.Net,
    59  				TLSConfig: &tls.Config{
    60  					ClientSessionCache: globalSessionCache,
    61  					// alpn identifier, see https://tools.ietf.org/html/draft-hoffman-dprive-dns-tls-alpn-00#page-6
    62  					NextProtos: []string{"dns"},
    63  					ServerName: host,
    64  				},
    65  				UDPSize: 4096,
    66  				Timeout: 5 * time.Second,
    67  			},
    68  			port: port,
    69  			host: host,
    70  			r:    resolver,
    71  		})
    72  	}
    73  	return ret
    74  }