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cc575fe4d6
Two changes in one: * make DoH upgrades an explicitly scheduled send earlier, when we come up with the resolvers-and-delay send plan. Previously we were getting e.g. four Google DNS IPs and then spreading them out in time (for back when we only did UDP) but then later we added DoH upgrading at the UDP packet layer, which resulted in sometimes multiple DoH queries to the same provider running (each doing happy eyeballs dialing to 4x IPs themselves) for each of the 4 source IPs. Instead, take those 4 Google/Cloudflare IPs and schedule 5 things: first the DoH query (which can use all 4 IPs), and then each of the 4 IPs as UDP later. * clean up the dnstype.Resolver.Addr confusion; half the code was using it as an IP string (as documented) as half was using it as an IP:port (from some prior type we used), primarily for tests. Instead, document it was being primarily an IP string but also accepting an IP:port for tests, then add an accessor method on it to get the IPPort and use that consistently everywhere. Change-Id: Ifdd72b9e45433a5b9c029194d50db2b9f9217b53 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
48 lines
1.7 KiB
Go
48 lines
1.7 KiB
Go
// Copyright (c) 2021 Tailscale Inc & 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 dnstype defines types for working with DNS.
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package dnstype
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//go:generate go run tailscale.com/cmd/cloner --type=Resolver --clonefunc=true --output=dnstype_clone.go
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import "inet.af/netaddr"
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// Resolver is the configuration for one DNS resolver.
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type Resolver struct {
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// Addr is the address of the DNS resolver, one of:
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// - A plain IP address for a "classic" UDP+TCP DNS resolver.
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// This is the common format as sent by the control plane.
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// - An IP:port, for tests.
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// - [TODO] "tls://resolver.com" for DNS over TCP+TLS
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// - [TODO] "https://resolver.com/query-tmpl" for DNS over HTTPS
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Addr string `json:",omitempty"`
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// BootstrapResolution is an optional suggested resolution for the
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// DoT/DoH resolver, if the resolver URL does not reference an IP
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// address directly.
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// BootstrapResolution may be empty, in which case clients should
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// look up the DoT/DoH server using their local "classic" DNS
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// resolver.
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BootstrapResolution []netaddr.IP `json:",omitempty"`
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}
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// IPPort returns r.Addr as an IP address and port if either
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// r.Addr is an IP address (the common case) or if r.Addr
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// is an IP:port (as done in tests).
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func (r *Resolver) IPPort() (ipp netaddr.IPPort, ok bool) {
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if r.Addr == "" || r.Addr[0] == 'h' || r.Addr[0] == 't' {
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// Fast path to avoid ParseIP error allocation for obviously not IP
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// cases.
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return
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}
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if ip, err := netaddr.ParseIP(r.Addr); err == nil {
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return netaddr.IPPortFrom(ip, 53), true
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}
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if ipp, err := netaddr.ParseIPPort(r.Addr); err == nil {
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return ipp, true
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}
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return
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}
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