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9dc7194321
See https://github.com/hashicorp/consul/issues/3977 While trying to improve furthermore #3948 (This pull request is still valid since we are not using Compression to compute the result anyway). I saw a strange behaviour of dns library. Basically, msg.Len() and len(msg.Pack()) disagree on Message len. Thus, calculation of DNS response is false consul relies on msg.Len() instead of the result of Pack() This is linked to miekg/dns#453 and a fix has been provided with miekg/dns#454 Would it be possible to upgrade miekg/dns to a more recent function ? Consul might for instance upgrade to a post 1.0 release such as https://github.com/miekg/dns/releases/tag/v1.0.4
70 lines
2.2 KiB
Go
70 lines
2.2 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ipv4
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import (
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"net"
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"syscall"
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"golang.org/x/net/internal/socket"
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)
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// BUG(mikio): On Windows, the ReadFrom and WriteTo methods of RawConn
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// are not implemented.
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// A packetHandler represents the IPv4 datagram handler.
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type packetHandler struct {
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*net.IPConn
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*socket.Conn
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rawOpt
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}
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func (c *packetHandler) ok() bool { return c != nil && c.IPConn != nil && c.Conn != nil }
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// ReadFrom reads an IPv4 datagram from the endpoint c, copying the
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// datagram into b. It returns the received datagram as the IPv4
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// header h, the payload p and the control message cm.
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func (c *packetHandler) ReadFrom(b []byte) (h *Header, p []byte, cm *ControlMessage, err error) {
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if !c.ok() {
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return nil, nil, nil, syscall.EINVAL
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}
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return c.readFrom(b)
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}
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func slicePacket(b []byte) (h, p []byte, err error) {
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if len(b) < HeaderLen {
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return nil, nil, errHeaderTooShort
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}
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hdrlen := int(b[0]&0x0f) << 2
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return b[:hdrlen], b[hdrlen:], nil
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}
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// WriteTo writes an IPv4 datagram through the endpoint c, copying the
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// datagram from the IPv4 header h and the payload p. The control
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// message cm allows the datagram path and the outgoing interface to be
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// specified. Currently only Darwin and Linux support this. The cm
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// may be nil if control of the outgoing datagram is not required.
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//
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// The IPv4 header h must contain appropriate fields that include:
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//
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// Version = <must be specified>
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// Len = <must be specified>
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// TOS = <must be specified>
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// TotalLen = <must be specified>
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// ID = platform sets an appropriate value if ID is zero
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// FragOff = <must be specified>
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// TTL = <must be specified>
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// Protocol = <must be specified>
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// Checksum = platform sets an appropriate value if Checksum is zero
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// Src = platform sets an appropriate value if Src is nil
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// Dst = <must be specified>
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// Options = optional
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func (c *packetHandler) WriteTo(h *Header, p []byte, cm *ControlMessage) error {
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if !c.ok() {
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return syscall.EINVAL
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}
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return c.writeTo(h, p, cm)
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}
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