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|
package vnet
import (
"errors"
"fmt"
"net"
"sync"
"github.com/pion/logging"
)
var (
errHostnameEmpty = errors.New("host name must not be empty")
errFailedtoParseIPAddr = errors.New("failed to parse IP address")
)
type resolverConfig struct {
LoggerFactory logging.LoggerFactory
}
type resolver struct {
parent *resolver // read-only
hosts map[string]net.IP // requires mutex
mutex sync.RWMutex // thread-safe
log logging.LeveledLogger // read-only
}
func newResolver(config *resolverConfig) *resolver {
r := &resolver{
hosts: map[string]net.IP{},
log: config.LoggerFactory.NewLogger("vnet"),
}
if err := r.addHost("localhost", "127.0.0.1"); err != nil {
r.log.Warn("failed to add localhost to resolver")
}
return r
}
func (r *resolver) setParent(parent *resolver) {
r.mutex.Lock()
defer r.mutex.Unlock()
r.parent = parent
}
func (r *resolver) addHost(name string, ipAddr string) error {
r.mutex.Lock()
defer r.mutex.Unlock()
if len(name) == 0 {
return errHostnameEmpty
}
ip := net.ParseIP(ipAddr)
if ip == nil {
return fmt.Errorf("%w \"%s\"", errFailedtoParseIPAddr, ipAddr)
}
r.hosts[name] = ip
return nil
}
func (r *resolver) lookUp(hostName string) (net.IP, error) {
ip := func() net.IP {
r.mutex.RLock()
defer r.mutex.RUnlock()
if ip2, ok := r.hosts[hostName]; ok {
return ip2
}
return nil
}()
if ip != nil {
return ip, nil
}
// mutex must be unlocked before calling into parent resolver
if r.parent != nil {
return r.parent.lookUp(hostName)
}
return nil, &net.DNSError{
Err: "host not found",
Name: hostName,
Server: "vnet resolver",
IsTimeout: false,
IsTemporary: false,
}
}
|
