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Fix timeouts, Tsig and EDNS0 update size

This commit is contained in:
Miek Gieben 2013-09-29 11:21:18 +01:00
parent b97b3340fb
commit 9a38f97391
3 changed files with 57 additions and 36 deletions
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89
client.go
View File

@ -12,9 +12,13 @@ import (
"time"
)
const dnsTimeout time.Duration = 2 * 1e9
// A Conn represents a connection (which may be short lived) to a DNS server.
type Conn struct {
net.Conn
UDPSize uint16 // Minimum reveive buffer for UDP messages, if > 512 EDNS0, 0 MinMsgSize.
TsigSecret map[string]string // Secret(s) for Tsig map[<zonename>]<base64 secret>, zonename must be fully qualified
rtt time.Duration
t time.Time
requestMAC string
@ -23,8 +27,9 @@ type Conn struct {
// A Client defines parameters for a DNS client. A nil Client is usable for sending queries.
type Client struct {
Net string // if "tcp" a TCP query will be initiated, otherwise an UDP one (default is "" for UDP)
ReadTimeout time.Duration // the net.Conn.SetReadTimeout value for new connections (ns), defaults to 2 * 1e9
WriteTimeout time.Duration // the net.Conn.SetWriteTimeout value for new connections (ns), defaults to 2 * 1e9
DialTimeout time.Duration // net.DialTimeout (ns), defaults to 2 * 1e9
ReadTimeout time.Duration // net.Conn.SetReadTimeout value for new connections (ns), defaults to 2 * 1e9
WriteTimeout time.Duration // net.Conn.SetWriteTimeout value for new connections (ns), defaults to 2 * 1e9
TsigSecret map[string]string // secret(s) for Tsig map[<zonename>]<base64 secret>, zonename must be fully qualified
SingleInflight bool // if true suppress multiple outstanding queries for the same Qname, Qtype and Qclass
group singleflight
@ -34,15 +39,15 @@ type Client struct {
// contained in a and waits for an reply.
func Exchange(m *Msg, a string) (r *Msg, err error) {
co := new(Conn)
co.Conn, err = net.DialTimeout("udp", a, 5*1e9)
co.Conn, err = net.DialTimeout("udp", a, dnsTimeout)
if err != nil {
return nil, err
}
defer co.Close()
if err = co.WriteMsg(m, nil); err != nil {
if err = co.WriteMsg(m); err != nil {
return nil, err
}
r, err = co.ReadMsg(nil)
r, err = co.ReadMsg()
return r, err
}
@ -80,31 +85,43 @@ func (c *Client) Exchange(m *Msg, a string) (r *Msg, rtt time.Duration, err erro
func (c *Client) exchange(m *Msg, a string) (r *Msg, rtt time.Duration, err error) {
co := new(Conn)
timeout := dnsTimeout
if c.DialTimeout != 0 {
timeout = c.DialTimeout
}
if c.Net == "" {
co.Conn, err = net.DialTimeout("udp", a, 5*1e9)
co.Conn, err = net.DialTimeout("udp", a, timeout)
} else {
co.Conn, err = net.DialTimeout(c.Net, a, 5*1e9)
co.Conn, err = net.DialTimeout(c.Net, a, timeout)
}
if err != nil {
return nil, 0, err
}
defer co.Close()
if err = co.WriteMsg(m, c.TsigSecret); err != nil {
opt := m.IsEdns0()
if opt != nil && opt.UDPSize() >= MinMsgSize {
co.UDPSize = opt.UDPSize()
}
co.TsigSecret = c.TsigSecret
if err = co.WriteMsg(m); err != nil {
return nil, 0, err
}
r, err = co.ReadMsg(c.TsigSecret)
r, err = co.ReadMsg()
return r, co.rtt, err
}
// Add bufsize
func (co *Conn) ReadMsg(tsigSecret map[string]string) (*Msg, error) {
// ReadMsg reads a message from the connection co.
func (co *Conn) ReadMsg() (*Msg, error) {
var p []byte
m := new(Msg)
if _, ok := co.Conn.(*net.TCPConn); ok {
p = make([]byte, MaxMsgSize)
} else {
// OPT! TODO(miek): needs function change
p = make([]byte, DefaultMsgSize)
if co.UDPSize >= 512 {
p = make([]byte, co.UDPSize)
} else {
p = make([]byte, MinMsgSize)
}
}
n, err := co.Read(p)
if err != nil && n == 0 {
@ -116,15 +133,16 @@ func (co *Conn) ReadMsg(tsigSecret map[string]string) (*Msg, error) {
}
co.rtt = time.Since(co.t)
if t := m.IsTsig(); t != nil {
if _, ok := tsigSecret[t.Hdr.Name]; !ok {
if _, ok := co.TsigSecret[t.Hdr.Name]; !ok {
return m, ErrSecret
}
// Need to work on the original message p, as that was used to calculate the tsig.
err = TsigVerify(p, tsigSecret[t.Hdr.Name], co.requestMAC, false)
err = TsigVerify(p, co.TsigSecret[t.Hdr.Name], co.requestMAC, false)
}
return m, err
}
// Read implements the net.Conn read method.
func (co *Conn) Read(p []byte) (n int, err error) {
if co.Conn == nil {
return 0, ErrConnEmpty
@ -167,18 +185,18 @@ func (co *Conn) Read(p []byte) (n int, err error) {
return n, err
}
// send sends a dns msg to the address specified in w.
// WriteMsg send a dns message throught the connection co.
// If the message m contains a TSIG record the transaction
// signature is calculated.
func (co *Conn) WriteMsg(m *Msg, tsigSecret map[string]string) (err error) {
func (co *Conn) WriteMsg(m *Msg) (err error) {
var out []byte
if t := m.IsTsig(); t != nil {
mac := ""
if _, ok := tsigSecret[t.Hdr.Name]; !ok {
if _, ok := co.TsigSecret[t.Hdr.Name]; !ok {
return ErrSecret
}
out, mac, err = TsigGenerate(m, tsigSecret[t.Hdr.Name], co.requestMAC, false)
// Set for the next read
out, mac, err = TsigGenerate(m, co.TsigSecret[t.Hdr.Name], co.requestMAC, false)
// Set for the next read, allthough only used in zone transfers
co.requestMAC = mac
} else {
out, err = m.Pack()
@ -193,6 +211,7 @@ func (co *Conn) WriteMsg(m *Msg, tsigSecret map[string]string) (err error) {
return nil
}
// Write implements the net.Conn Write method.
func (co *Conn) Write(p []byte) (n int, err error) {
if t, ok := co.Conn.(*net.TCPConn); ok {
if len(p) < 2 {
@ -220,18 +239,20 @@ func (co *Conn) Write(p []byte) (n int, err error) {
return n, err
}
/*
func setTimeouts(w *reply) {
if w.client.ReadTimeout == 0 {
w.conn.SetReadDeadline(time.Now().Add(2 * 1e9))
} else {
w.conn.SetReadDeadline(time.Now().Add(w.client.ReadTimeout))
}
// Close implements the net.Conn Close method.
func (co *Conn) Close() error { return co.Conn.Close() }
if w.client.WriteTimeout == 0 {
w.conn.SetWriteDeadline(time.Now().Add(2 * 1e9))
} else {
w.conn.SetWriteDeadline(time.Now().Add(w.client.WriteTimeout))
}
}
*/
// LocalAddr implements the net.Conn LocalAddr method.
func (co *Conn) LocalAddr() net.Addr { return co.Conn.LocalAddr() }
// RemoteAddr implements the net.Conn RemoteAddr method.
func (co *Conn) RemoteAddr() net.Addr { return co.Conn.RemoteAddr() }
// SetDeadline implements the net.Conn SetDeadline method.
func (co *Conn) SetDeadline(t time.Time) error { return co.Conn.SetDeadline(t) }
// SetReadDeadline implements the net.Conn SetReadDeadline method.
func (co *Conn) SetReadDeadline(t time.Time) error { return co.Conn.SetReadDeadline(t) }
// SetWriteDeadline implements the net.Conn SetWriteDeadline method.
func (co *Conn) SetWriteDeadline(t time.Time) error { return co.Conn.SetWriteDeadline(t) }

2
dns.go
View File

@ -91,7 +91,7 @@ import (
const (
year68 = 1 << 31 // For RFC1982 (Serial Arithmetic) calculations in 32 bits.
DefaultMsgSize = 4096 // Standard default for larger than 512 packets.
udpMsgSize = 512 // Default buffer size for servers receiving UDP packets.
MinMsgSize = 512 // Minimal size of a DNS packet.
MaxMsgSize = 65536 // Largest possible DNS packet.
defaultTtl = 3600 // Default TTL.
)

2
server.go
View File

@ -355,7 +355,7 @@ func (srv *Server) serveUDP(l *net.UDPConn) error {
handler = DefaultServeMux
}
if srv.UDPSize == 0 {
srv.UDPSize = udpMsgSize
srv.UDPSize = MinMsgSize
}
for {
if srv.ReadTimeout != 0 {