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package solver
import (
"gopkg.in/hlandau/acmeapi.v2"
"sort"
)
// Any challenge having a preference at or below this value will never be used.
const NonviableThreshold int32 = -1000000
type sorter struct {
authz *acmeapi.Authorization
order []int
preferencer Preferencer
}
func (s *sorter) Len() int {
return len(s.order)
}
func (s *sorter) Swap(i, j int) {
s.order[i], s.order[j] = s.order[j], s.order[i]
}
func (s *sorter) Less(i, j int) bool {
pi := s.preference(&s.authz.Challenges[i])
pj := s.preference(&s.authz.Challenges[j])
return pi < pj
}
func (s *sorter) preference(ch *acmeapi.Challenge) int32 {
v := s.preferencer.Preference(ch)
if v <= NonviableThreshold {
return NonviableThreshold
}
return v
}
// Returns a list of indices to authz.Challenges, sorted by preference, most
// preferred first.
func SortChallenges(authz *acmeapi.Authorization, preferencer Preferencer) (preferenceOrder []int) {
preferenceOrder = make([]int, len(authz.Challenges))
for i := 0; i < len(authz.Challenges); i++ {
preferenceOrder[i] = i
}
s := sorter{
authz: authz,
order: preferenceOrder,
preferencer: preferencer,
}
sort.Stable(sort.Reverse(&s))
return
}
// TypePreferencer returns a preference according to the type of the challenge.
//
// Unknown challenge types are nonviable.
type TypePreferencer map[string]int32
// Implements Preferencer.
func (p TypePreferencer) Preference(ch *acmeapi.Challenge) int32 {
v, ok := p[ch.Type]
if !ok {
return NonviableThreshold
}
return v
}
// Returns a copy of TypePreferencer, so that it can be mutated without
// changing the original.
func (p TypePreferencer) Copy() TypePreferencer {
tp := TypePreferencer{}
for k, v := range p {
tp[k] = v
}
return tp
}
// PreferFast prefers fast types.
var PreferFast = TypePreferencer{
"tls-sni-02": 2,
"tls-sni-01": 1,
"http-01": 0,
// Disable DNS challenges for now. They're practically unusable and the Let's
// Encrypt live server doesn't support them at this time anyway.
"dns-01": -10,
}
// Determines the degree to which a challenge is preferred. Higher values are
// more preferred. Any value <= NonviableThreshold will never be used.
type Preferencer interface {
// Get the preference for the given challenge.
Preference(ch *acmeapi.Challenge) int32
}
|
