133 lines
2.6 KiB
Go
133 lines
2.6 KiB
Go
package router
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import (
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"fmt"
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"strings"
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"github.com/olekukonko/tablewriter"
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)
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// LookupPolicy defines query policy
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type LookupPolicy int
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const (
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// DiscardIfNone discards query when no route is found
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DiscardIfNone LookupPolicy = iota
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// ClosestMatch returns closest match to supplied query
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ClosestMatch
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)
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// String returns human representation of LookupPolicy
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func (lp LookupPolicy) String() string {
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switch lp {
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case DiscardIfNone:
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return "DISCARD"
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case ClosestMatch:
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return "CLOSEST"
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default:
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return "UNKNOWN"
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}
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}
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// QueryOption sets routing table query options
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type QueryOption func(*QueryOptions)
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// QueryOptions are routing table query options
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type QueryOptions struct {
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// Destination is destination address
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Destination string
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// Network is network address
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Network string
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// Router is router address
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Router string
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// Policy is query lookup policy
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Policy LookupPolicy
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}
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// QueryDestination sets destination address
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func QueryDestination(d string) QueryOption {
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return func(o *QueryOptions) {
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o.Destination = d
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}
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}
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// QueryNetwork sets route network address
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func QueryNetwork(a string) QueryOption {
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return func(o *QueryOptions) {
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o.Network = a
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}
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}
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// QueryRouter sets route router address
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func QueryRouter(r string) QueryOption {
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return func(o *QueryOptions) {
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o.Router = r
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}
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}
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// QueryPolicy sets query policy
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// NOTE: this might be renamed to filter or some such
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func QueryPolicy(p LookupPolicy) QueryOption {
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return func(o *QueryOptions) {
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o.Policy = p
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}
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}
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// Query is routing table query
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type Query interface {
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// Options returns query options
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Options() QueryOptions
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}
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// query is a basic implementation of Query
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type query struct {
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opts QueryOptions
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}
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// NewQuery creates new query and returns it
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func NewQuery(opts ...QueryOption) Query {
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// default options
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// NOTE: by default we use DefaultNetworkMetric
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qopts := QueryOptions{
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Destination: "*",
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Network: "*",
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Policy: DiscardIfNone,
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}
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for _, o := range opts {
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o(&qopts)
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}
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return &query{
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opts: qopts,
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}
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}
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// Options returns query options
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func (q *query) Options() QueryOptions {
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return q.opts
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}
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// String prints routing table query in human readable form
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func (q query) String() string {
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// this will help us build routing table string
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sb := &strings.Builder{}
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// create nice table printing structure
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table := tablewriter.NewWriter(sb)
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table.SetHeader([]string{"Destination", "Network", "Router", "Policy"})
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strQuery := []string{
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q.opts.Destination,
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q.opts.Network,
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q.opts.Router,
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fmt.Sprintf("%s", q.opts.Policy),
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}
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table.Append(strQuery)
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// render table into sb
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table.Render()
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return sb.String()
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}
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