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resolver.go
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resolver.go
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package resolver
import (
"github.com/miekg/dns"
"strings"
)
type Resolver struct {
zones *zones
}
func NewResolver() *Resolver {
pool, err := buildRootServerPool()
if err != nil {
// Everything is technically static at this point.
panic(err)
}
z := new(zones)
z.add(&zone{
name: ".",
pool: pool,
})
return &Resolver{
zones: z,
}
}
//-----------------------------------------------------------------------------
func buildRootServerPool() (*nameserverPool, error) {
zp := dns.NewZoneParser(strings.NewReader(rootZone), ".", "local")
pool := &nameserverPool{hostsWithoutAddresses: make([]string, 0)}
for rr, ok := zp.Next(); ok; rr, ok = zp.Next() {
switch rr := rr.(type) {
case *dns.A:
pool.ipv4 = append(pool.ipv4, &nameserver{
hostname: canonicalName(rr.Header().Name),
addr: rr.A.String(),
})
case *dns.AAAA:
pool.ipv6 = append(pool.ipv6, &nameserver{
hostname: canonicalName(rr.Header().Name),
addr: rr.AAAA.String(),
})
default:
// Continue
}
}
if err := zp.Err(); err != nil {
return nil, err
}
return pool, nil
}