108 lines
2.6 KiB
Go
108 lines
2.6 KiB
Go
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package graph
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import (
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"crypto/sha256"
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"encoding/json"
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"github.com/miekg/dns"
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"strings"
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)
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/* serializedAliasNode is a proxy struct used to serialize an Alias node into JSON.
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The AliasNode struct is not directly used because the Go json module requires that attributes must be exported for it
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to work, and AliasNode struct attributes have no other reason for being exported.
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*/
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type serializedAliasNode struct {
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Target string `json:"target"`
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Source string `json:"source"`
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}
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// AliasNode represents a CNAME in the dependency graph of a name.
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type AliasNode struct {
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// target is the right-hand name of the CNAME RR
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target string
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// source is the owner name of the CNAME RR
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source string
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// parentNode is a reference to the parent node in the dependency graph. This is used to visit the graph from leafs
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// to root
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parentNode Node
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}
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/* NewAliasNode returns a new instance of AliasNode after initializing it.
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target is the right-hand name of the CNAME RR
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source is the owner name of the CNAME RR
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*/
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func NewAliasNode(target, source string) *AliasNode {
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n := new(AliasNode)
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n.target = strings.ToLower(dns.Fqdn(target))
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n.source = strings.ToLower(dns.Fqdn(source))
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return n
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}
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// Implements json.Marshaler
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func (n *AliasNode) MarshalJSON() ([]byte, error) {
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sn := new(serializedAliasNode)
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sn.Target = n.target
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sn.Source = n.source
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return json.Marshal(sn)
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}
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// Implements json.Unmarshaler
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func (n *AliasNode) UnmarshalJSON(bstr []byte) error {
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sn := new(serializedAliasNode)
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err := json.Unmarshal(bstr, sn)
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if err != nil {
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return err
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}
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n.target = sn.Target
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n.source = sn.Source
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return nil
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}
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func (n *AliasNode) Target() string {
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return n.target
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}
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func (n *AliasNode) Source() string {
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return n.source
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}
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func (n *AliasNode) String() string {
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jsonbstr, err := json.Marshal(n)
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if err != nil {
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return ""
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}
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return string(jsonbstr)
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}
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func (n *AliasNode) deepcopy() Node {
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nn := new(AliasNode)
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nn.target = n.target
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nn.source = n.source
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nn.parentNode = n.parentNode
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return nn
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}
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func (n *AliasNode) setParent(g Node) {
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n.parentNode = g
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}
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func (n *AliasNode) parent() Node {
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return n.parentNode
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}
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// similar compares to LeafNode and returns true if the o LeafNode is also an AliasNode and the targets are the same.
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func (n *AliasNode) similar(o LeafNode) bool {
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otherDomain, ok := o.(*AliasNode)
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// It is safe to use == here to compare domain names b/c NewAliasNode performs canonicalization of the domain names
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return ok && n.target == otherDomain.target //&& n.source == otherDomain.source
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}
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func (n *AliasNode) hash() [8]byte {
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var ret [8]byte
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h := sha256.Sum256([]byte(n.target + n.source))
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copy(ret[:], h[:8])
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return ret
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}
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