Merge branch 'fhriley-udp-buf-size'

README.md

@@ -46,8 +46,7 @@ Application Options:
   -y, --dnscrypt-port=   Listening ports for DNSCrypt
   -c, --tls-crt=         Path to a file with the certificate chain
   -k, --tls-key=         Path to a file with the private key
-  -g, --dnscrypt-config= Path to a file with DNSCrypt configuration. You can generate one using
-                         https://github.com/ameshkov/dnscrypt
+  -g, --dnscrypt-config= Path to a file with DNSCrypt configuration. You can generate one using https://github.com/ameshkov/dnscrypt
   -u, --upstream=        An upstream to be used (can be specified multiple times)
   -b, --bootstrap=       Bootstrap DNS for DoH and DoT, can be specified multiple times (default: 8.8.8.8:53)
   -f, --fallback=        Fallback resolvers to use when regular ones are unavailable, can be specified multiple times
@@ -55,16 +54,16 @@ Application Options:
       --fastest-addr     Respond to A or AAAA requests only with the fastest IP address
       --cache            If specified, DNS cache is enabled
       --cache-size=      Cache size (in bytes). Default: 64k
-      --cache-min-ttl=   Minimum TTL value for DNS entries, in seconds. Capped at 3600. Artificially extending TTLs should
-                         only be done with careful consideration.
+      --cache-min-ttl=   Minimum TTL value for DNS entries, in seconds. Capped at 3600. Artificially extending TTLs should only be done with careful consideration.
       --cache-max-ttl=   Maximum TTL value for DNS entries, in seconds.
   -r, --ratelimit=       Ratelimit (requests per second) (default: 0)
       --refuse-any       If specified, refuse ANY requests
       --edns             Use EDNS Client Subnet extension
       --edns-addr=       Send EDNS Client Address
       --ipv6-disabled    If specified, all AAAA requests will be replied with NoError RCode and empty answer
-      --bogus-nxdomain=  Transform responses that contain at least one of the given IP addresses into NXDOMAIN. Can be specified multiple
-                         times.
+      --bogus-nxdomain=  Transform responses that contain at least one of the given IP addresses into NXDOMAIN. Can be specified multiple times.
+      --udp-buf-size=    Set the size of the UDP buffer in bytes. A value <= 0 will use the system default. (default: 0)
+      --max-go-routines= Set the maximum number of go routines. A value <= 0 will not not set a maximum. (default: 0)
       --version          Prints the program version
 
 Help Options:

main.go

@@ -123,6 +123,12 @@ type Options struct {
 	// Transform responses that contain at least one of the given IP addresses into NXDOMAIN
 	BogusNXDomain []string `long:"bogus-nxdomain" description:"Transform responses that contain at least one of the given IP addresses into NXDOMAIN. Can be specified multiple times."`
 
+	// UDP buffer size value
+	UDPBufferSize int `long:"udp-buf-size" description:"Set the size of the UDP buffer in bytes. A value <= 0 will use the system default." default:"0"`
+
+	// The maximum number of go routines
+	MaxGoRoutines int `long:"max-go-routines" description:"Set the maximum number of go routines. A value <= 0 will not not set a maximum." default:"0"`
+
 	// Print DNSProxy version (just for the help)
 	Version bool `long:"version" description:"Prints the program version"`
 }
@@ -205,6 +211,8 @@ func createProxyConfig(options Options) proxy.Config {
 		CacheMaxTTL:            options.CacheMaxTTL,
 		RefuseAny:              options.RefuseAny,
 		EnableEDNSClientSubnet: options.EnableEDNSSubnet,
+		UDPBufferSize:          options.UDPBufferSize,
+		MaxGoroutines:          options.MaxGoRoutines,
 	}
 
 	initUpstreams(&config, options)

proxy/config.go

@@ -121,6 +121,10 @@ type Config struct {
 	// “MaxDNSRequestGoroutines” in a later major version, as it doesn't
 	// actually limit all goroutines.
 	MaxGoroutines int
+
+	// The size of the read buffer on the underlying socket. Larger read buffers can handle
+	// larger bursts of requests before packets get dropped.
+	UDPBufferSize int
 }
 
 // validateConfig verifies that the supplied configuration is valid and returns an error if it's not

proxy/server_udp.go

@@ -31,6 +31,14 @@ func (p *Proxy) udpCreate(udpAddr *net.UDPAddr) (*net.UDPConn, error) {
 		return nil, errorx.Decorate(err, "couldn't listen to UDP socket")
 	}
 
+	if p.Config.UDPBufferSize > 0 {
+		err = udpListen.SetReadBuffer(p.Config.UDPBufferSize)
+		if err != nil {
+			_ = udpListen.Close()
+			return nil, errorx.Decorate(err, "setting UDP buffer size failed")
+		}
+	}
+
 	err = proxyutil.UDPSetOptions(udpListen)
 	if err != nil {
 		_ = udpListen.Close()