a685e3fc98
Vndr has a simpler configuration and allows pointing to forked packages. Additionally other docker projects are now using vndr making vendoring in distribution more consistent. Updates letsencrypt to use fork. No longer uses sub-vendored packages. Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
84 lines
2 KiB
Go
84 lines
2 KiB
Go
package dns
|
|
|
|
// Dedup removes identical RRs from rrs. It preserves the original ordering.
|
|
// The lowest TTL of any duplicates is used in the remaining one. Dedup modifies
|
|
// rrs.
|
|
// m is used to store the RRs temporay. If it is nil a new map will be allocated.
|
|
func Dedup(rrs []RR, m map[string]RR) []RR {
|
|
if m == nil {
|
|
m = make(map[string]RR)
|
|
}
|
|
// Save the keys, so we don't have to call normalizedString twice.
|
|
keys := make([]*string, 0, len(rrs))
|
|
|
|
for _, r := range rrs {
|
|
key := normalizedString(r)
|
|
keys = append(keys, &key)
|
|
if _, ok := m[key]; ok {
|
|
// Shortest TTL wins.
|
|
if m[key].Header().Ttl > r.Header().Ttl {
|
|
m[key].Header().Ttl = r.Header().Ttl
|
|
}
|
|
continue
|
|
}
|
|
|
|
m[key] = r
|
|
}
|
|
// If the length of the result map equals the amount of RRs we got,
|
|
// it means they were all different. We can then just return the original rrset.
|
|
if len(m) == len(rrs) {
|
|
return rrs
|
|
}
|
|
|
|
j := 0
|
|
for i, r := range rrs {
|
|
// If keys[i] lives in the map, we should copy and remove it.
|
|
if _, ok := m[*keys[i]]; ok {
|
|
delete(m, *keys[i])
|
|
rrs[j] = r
|
|
j++
|
|
}
|
|
|
|
if len(m) == 0 {
|
|
break
|
|
}
|
|
}
|
|
|
|
return rrs[:j]
|
|
}
|
|
|
|
// normalizedString returns a normalized string from r. The TTL
|
|
// is removed and the domain name is lowercased. We go from this:
|
|
// DomainName<TAB>TTL<TAB>CLASS<TAB>TYPE<TAB>RDATA to:
|
|
// lowercasename<TAB>CLASS<TAB>TYPE...
|
|
func normalizedString(r RR) string {
|
|
// A string Go DNS makes has: domainname<TAB>TTL<TAB>...
|
|
b := []byte(r.String())
|
|
|
|
// find the first non-escaped tab, then another, so we capture where the TTL lives.
|
|
esc := false
|
|
ttlStart, ttlEnd := 0, 0
|
|
for i := 0; i < len(b) && ttlEnd == 0; i++ {
|
|
switch {
|
|
case b[i] == '\\':
|
|
esc = !esc
|
|
case b[i] == '\t' && !esc:
|
|
if ttlStart == 0 {
|
|
ttlStart = i
|
|
continue
|
|
}
|
|
if ttlEnd == 0 {
|
|
ttlEnd = i
|
|
}
|
|
case b[i] >= 'A' && b[i] <= 'Z' && !esc:
|
|
b[i] += 32
|
|
default:
|
|
esc = false
|
|
}
|
|
}
|
|
|
|
// remove TTL.
|
|
copy(b[ttlStart:], b[ttlEnd:])
|
|
cut := ttlEnd - ttlStart
|
|
return string(b[:len(b)-cut])
|
|
}
|