net: make all Resolver methods respect Resolver.PreferGo

Fixes #17532

Change-Id: Id62671d505c77ea924b3570a504cdc3b157e5a0d
Reviewed-on: https://go-review.googlesource.com/31734
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/net/lookup.go b/src/net/lookup.go
index d1e2e0063d579dc41dc1200610ad1c3e0191c444..28e23fa1c11914c5b27ca105882100fabed668fc 100644 (file)
--- a/src/net/lookup.go
+++ b/src/net/lookup.go
@@ -101,13 +101,6 @@ type Resolver struct {
        // TODO(bradfitz): Timeout time.Duration?
 }
 
-func (r *Resolver) lookupIPFunc() func(context.Context, string) ([]IPAddr, error) {
-       if r != nil && r.PreferGo {
-               return goLookupIP
-       }
-       return lookupIP
-}
-
 // LookupHost looks up the given host using the local resolver.
 // It returns a slice of that host's addresses.
 func LookupHost(host string) (addrs []string, err error) {
@@ -125,7 +118,7 @@ func (r *Resolver) LookupHost(ctx context.Context, host string) (addrs []string,
        if ip := ParseIP(host); ip != nil {
                return []string{host}, nil
        }
-       return lookupHost(ctx, host)
+       return r.lookupHost(ctx, host)
 }
 
 // LookupIP looks up host using the local resolver.
@@ -160,7 +153,7 @@ func (r *Resolver) LookupIPAddr(ctx context.Context, host string) ([]IPAddr, err
        // The underlying resolver func is lookupIP by default but it
        // can be overridden by tests. This is needed by net/http, so it
        // uses a context key instead of unexported variables.
-       resolverFunc := r.lookupIPFunc()
+       resolverFunc := r.lookupIP
        if alt, _ := ctx.Value(nettrace.LookupIPAltResolverKey{}).(func(context.Context, string) ([]IPAddr, error)); alt != nil {
                resolverFunc = alt
        }
@@ -229,7 +222,7 @@ func LookupPort(network, service string) (port int, err error) {
 func (r *Resolver) LookupPort(ctx context.Context, network, service string) (port int, err error) {
        port, needsLookup := parsePort(service)
        if needsLookup {
-               port, err = lookupPort(ctx, network, service)
+               port, err = r.lookupPort(ctx, network, service)
                if err != nil {
                        return 0, err
                }
@@ -245,7 +238,7 @@ func (r *Resolver) LookupPort(ctx context.Context, network, service string) (por
 // LookupHost or LookupIP directly; both take care of resolving
 // the canonical name as part of the lookup.
 func LookupCNAME(name string) (cname string, err error) {
-       return lookupCNAME(context.Background(), name)
+       return DefaultResolver.lookupCNAME(context.Background(), name)
 }
 
 // LookupCNAME returns the canonical DNS host for the given name.
@@ -253,7 +246,7 @@ func LookupCNAME(name string) (cname string, err error) {
 // LookupHost or LookupIP directly; both take care of resolving
 // the canonical name as part of the lookup.
 func (r *Resolver) LookupCNAME(ctx context.Context, name string) (cname string, err error) {
-       return lookupCNAME(ctx, name)
+       return r.lookupCNAME(ctx, name)
 }
 
 // LookupSRV tries to resolve an SRV query of the given service,
@@ -266,7 +259,7 @@ func (r *Resolver) LookupCNAME(ctx context.Context, name string) (cname string,
 // publishing SRV records under non-standard names, if both service
 // and proto are empty strings, LookupSRV looks up name directly.
 func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err error) {
-       return lookupSRV(context.Background(), service, proto, name)
+       return DefaultResolver.lookupSRV(context.Background(), service, proto, name)
 }
 
 // LookupSRV tries to resolve an SRV query of the given service,
@@ -279,47 +272,47 @@ func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err err
 // publishing SRV records under non-standard names, if both service
 // and proto are empty strings, LookupSRV looks up name directly.
 func (r *Resolver) LookupSRV(ctx context.Context, service, proto, name string) (cname string, addrs []*SRV, err error) {
-       return lookupSRV(ctx, service, proto, name)
+       return r.lookupSRV(ctx, service, proto, name)
 }
 
 // LookupMX returns the DNS MX records for the given domain name sorted by preference.
 func LookupMX(name string) ([]*MX, error) {
-       return lookupMX(context.Background(), name)
+       return DefaultResolver.lookupMX(context.Background(), name)
 }
 
 // LookupMX returns the DNS MX records for the given domain name sorted by preference.
 func (r *Resolver) LookupMX(ctx context.Context, name string) ([]*MX, error) {
-       return lookupMX(ctx, name)
+       return r.lookupMX(ctx, name)
 }
 
 // LookupNS returns the DNS NS records for the given domain name.
 func LookupNS(name string) ([]*NS, error) {
-       return lookupNS(context.Background(), name)
+       return DefaultResolver.lookupNS(context.Background(), name)
 }
 
 // LookupNS returns the DNS NS records for the given domain name.
 func (r *Resolver) LookupNS(ctx context.Context, name string) ([]*NS, error) {
-       return lookupNS(ctx, name)
+       return r.lookupNS(ctx, name)
 }
 
 // LookupTXT returns the DNS TXT records for the given domain name.
 func LookupTXT(name string) ([]string, error) {
-       return lookupTXT(context.Background(), name)
+       return DefaultResolver.lookupTXT(context.Background(), name)
 }
 
 // LookupTXT returns the DNS TXT records for the given domain name.
 func (r *Resolver) LookupTXT(ctx context.Context, name string) ([]string, error) {
-       return lookupTXT(ctx, name)
+       return r.lookupTXT(ctx, name)
 }
 
 // LookupAddr performs a reverse lookup for the given address, returning a list
 // of names mapping to that address.
 func LookupAddr(addr string) (names []string, err error) {
-       return lookupAddr(context.Background(), addr)
+       return DefaultResolver.lookupAddr(context.Background(), addr)
 }
 
 // LookupAddr performs a reverse lookup for the given address, returning a list
 // of names mapping to that address.
 func (r *Resolver) LookupAddr(ctx context.Context, addr string) (names []string, err error) {
-       return lookupAddr(ctx, addr)
+       return r.lookupAddr(ctx, addr)
 }

diff --git a/src/net/lookup_nacl.go b/src/net/lookup_nacl.go
index 83ecdb50f5730462ef26db455d2fc058d7129870..43cebad76028c93d24a9e8c3013a6d4d775d9817 100644 (file)
--- a/src/net/lookup_nacl.go
+++ b/src/net/lookup_nacl.go
@@ -15,42 +15,38 @@ func lookupProtocol(ctx context.Context, name string) (proto int, err error) {
        return lookupProtocolMap(name)
 }
 
-func lookupHost(ctx context.Context, host string) (addrs []string, err error) {
+func (*Resolver) lookupHost(ctx context.Context, host string) (addrs []string, err error) {
        return nil, syscall.ENOPROTOOPT
 }
 
-func goLookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
+func (*Resolver) lookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
        return nil, syscall.ENOPROTOOPT
 }
 
-func lookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
-       return nil, syscall.ENOPROTOOPT
-}
-
-func lookupPort(ctx context.Context, network, service string) (port int, err error) {
+func (*Resolver) lookupPort(ctx context.Context, network, service string) (port int, err error) {
        return goLookupPort(network, service)
 }
 
-func lookupCNAME(ctx context.Context, name string) (cname string, err error) {
+func (*Resolver) lookupCNAME(ctx context.Context, name string) (cname string, err error) {
        return "", syscall.ENOPROTOOPT
 }
 
-func lookupSRV(ctx context.Context, service, proto, name string) (cname string, srvs []*SRV, err error) {
+func (*Resolver) lookupSRV(ctx context.Context, service, proto, name string) (cname string, srvs []*SRV, err error) {
        return "", nil, syscall.ENOPROTOOPT
 }
 
-func lookupMX(ctx context.Context, name string) (mxs []*MX, err error) {
+func (*Resolver) lookupMX(ctx context.Context, name string) (mxs []*MX, err error) {
        return nil, syscall.ENOPROTOOPT
 }
 
-func lookupNS(ctx context.Context, name string) (nss []*NS, err error) {
+func (*Resolver) lookupNS(ctx context.Context, name string) (nss []*NS, err error) {
        return nil, syscall.ENOPROTOOPT
 }
 
-func lookupTXT(ctx context.Context, name string) (txts []string, err error) {
+func (*Resolver) lookupTXT(ctx context.Context, name string) (txts []string, err error) {
        return nil, syscall.ENOPROTOOPT
 }
 
-func lookupAddr(ctx context.Context, addr string) (ptrs []string, err error) {
+func (*Resolver) lookupAddr(ctx context.Context, addr string) (ptrs []string, err error) {
        return nil, syscall.ENOPROTOOPT
 }

diff --git a/src/net/lookup_plan9.go b/src/net/lookup_plan9.go
index 3abaf090bacfa761f2c74da621111cf1a8af066d..b5cf7aaab561b0d81c144535805aeba229b3ff5a 100644 (file)
--- a/src/net/lookup_plan9.go
+++ b/src/net/lookup_plan9.go
@@ -117,7 +117,7 @@ func lookupProtocol(ctx context.Context, name string) (proto int, err error) {
        return 0, UnknownNetworkError(name)
 }
 
-func lookupHost(ctx context.Context, host string) (addrs []string, err error) {
+func (*Resolver) lookupHost(ctx context.Context, host string) (addrs []string, err error) {
        // Use netdir/cs instead of netdir/dns because cs knows about
        // host names in local network (e.g. from /lib/ndb/local)
        lines, err := queryCS(ctx, "net", host, "1")
@@ -148,10 +148,8 @@ loop:
        return
 }
 
-var goLookupIP = lookupIP
-
-func lookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
-       lits, err := lookupHost(ctx, host)
+func (r *Resolver) lookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
+       lits, err := r.lookupHost(ctx, host)
        if err != nil {
                return
        }
@@ -165,7 +163,7 @@ func lookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
        return
 }
 
-func lookupPort(ctx context.Context, network, service string) (port int, err error) {
+func (*Resolver) lookupPort(ctx context.Context, network, service string) (port int, err error) {
        switch network {
        case "tcp4", "tcp6":
                network = "tcp"
@@ -194,7 +192,7 @@ func lookupPort(ctx context.Context, network, service string) (port int, err err
        return 0, unknownPortError
 }
 
-func lookupCNAME(ctx context.Context, name string) (cname string, err error) {
+func (*Resolver) lookupCNAME(ctx context.Context, name string) (cname string, err error) {
        lines, err := queryDNS(ctx, name, "cname")
        if err != nil {
                return
@@ -207,7 +205,7 @@ func lookupCNAME(ctx context.Context, name string) (cname string, err error) {
        return "", errors.New("bad response from ndb/dns")
 }
 
-func lookupSRV(ctx context.Context, service, proto, name string) (cname string, addrs []*SRV, err error) {
+func (*Resolver) lookupSRV(ctx context.Context, service, proto, name string) (cname string, addrs []*SRV, err error) {
        var target string
        if service == "" && proto == "" {
                target = name
@@ -236,7 +234,7 @@ func lookupSRV(ctx context.Context, service, proto, name string) (cname string,
        return
 }
 
-func lookupMX(ctx context.Context, name string) (mx []*MX, err error) {
+func (*Resolver) lookupMX(ctx context.Context, name string) (mx []*MX, err error) {
        lines, err := queryDNS(ctx, name, "mx")
        if err != nil {
                return
@@ -254,7 +252,7 @@ func lookupMX(ctx context.Context, name string) (mx []*MX, err error) {
        return
 }
 
-func lookupNS(ctx context.Context, name string) (ns []*NS, err error) {
+func (*Resolver) lookupNS(ctx context.Context, name string) (ns []*NS, err error) {
        lines, err := queryDNS(ctx, name, "ns")
        if err != nil {
                return
@@ -269,7 +267,7 @@ func lookupNS(ctx context.Context, name string) (ns []*NS, err error) {
        return
 }
 
-func lookupTXT(ctx context.Context, name string) (txt []string, err error) {
+func (*Resolver) lookupTXT(ctx context.Context, name string) (txt []string, err error) {
        lines, err := queryDNS(ctx, name, "txt")
        if err != nil {
                return
@@ -282,7 +280,7 @@ func lookupTXT(ctx context.Context, name string) (txt []string, err error) {
        return
 }
 
-func lookupAddr(ctx context.Context, addr string) (name []string, err error) {
+func (*Resolver) lookupAddr(ctx context.Context, addr string) (name []string, err error) {
        arpa, err := reverseaddr(addr)
        if err != nil {
                return

diff --git a/src/net/lookup_unix.go b/src/net/lookup_unix.go
index fe84a6420808709675b883849190882c1bdab78f..35f253c1da24a7e72a2cdb6f396484f3c70f2ff8 100644 (file)
--- a/src/net/lookup_unix.go
+++ b/src/net/lookup_unix.go
@@ -48,9 +48,9 @@ func lookupProtocol(_ context.Context, name string) (int, error) {
        return lookupProtocolMap(name)
 }
 
-func lookupHost(ctx context.Context, host string) (addrs []string, err error) {
+func (r *Resolver) lookupHost(ctx context.Context, host string) (addrs []string, err error) {
        order := systemConf().hostLookupOrder(host)
-       if order == hostLookupCgo {
+       if !r.PreferGo && order == hostLookupCgo {
                if addrs, err, ok := cgoLookupHost(ctx, host); ok {
                        return addrs, err
                }
@@ -60,7 +60,10 @@ func lookupHost(ctx context.Context, host string) (addrs []string, err error) {
        return goLookupHostOrder(ctx, host, order)
 }
 
-func lookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
+func (r *Resolver) lookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
+       if r.PreferGo {
+               return goLookupIP(ctx, host)
+       }
        order := systemConf().hostLookupOrder(host)
        if order == hostLookupCgo {
                if addrs, err, ok := cgoLookupIP(ctx, host); ok {
@@ -72,13 +75,13 @@ func lookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
        return goLookupIPOrder(ctx, host, order)
 }
 
-func lookupPort(ctx context.Context, network, service string) (int, error) {
+func (r *Resolver) lookupPort(ctx context.Context, network, service string) (int, error) {
        // TODO: use the context if there ever becomes a need. Related
        // is issue 15321. But port lookup generally just involves
        // local files, and the os package has no context support. The
        // files might be on a remote filesystem, though. This should
        // probably race goroutines if ctx != context.Background().
-       if systemConf().canUseCgo() {
+       if !r.PreferGo && systemConf().canUseCgo() {
                if port, err, ok := cgoLookupPort(ctx, network, service); ok {
                        return port, err
                }
@@ -86,8 +89,8 @@ func lookupPort(ctx context.Context, network, service string) (int, error) {
        return goLookupPort(network, service)
 }
 
-func lookupCNAME(ctx context.Context, name string) (string, error) {
-       if systemConf().canUseCgo() {
+func (r *Resolver) lookupCNAME(ctx context.Context, name string) (string, error) {
+       if !r.PreferGo && systemConf().canUseCgo() {
                if cname, err, ok := cgoLookupCNAME(ctx, name); ok {
                        return cname, err
                }
@@ -95,7 +98,7 @@ func lookupCNAME(ctx context.Context, name string) (string, error) {
        return goLookupCNAME(ctx, name)
 }
 
-func lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) {
+func (*Resolver) lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) {
        var target string
        if service == "" && proto == "" {
                target = name
@@ -115,7 +118,7 @@ func lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV
        return cname, srvs, nil
 }
 
-func lookupMX(ctx context.Context, name string) ([]*MX, error) {
+func (*Resolver) lookupMX(ctx context.Context, name string) ([]*MX, error) {
        _, rrs, err := lookup(ctx, name, dnsTypeMX)
        if err != nil {
                return nil, err
@@ -129,7 +132,7 @@ func lookupMX(ctx context.Context, name string) ([]*MX, error) {
        return mxs, nil
 }
 
-func lookupNS(ctx context.Context, name string) ([]*NS, error) {
+func (*Resolver) lookupNS(ctx context.Context, name string) ([]*NS, error) {
        _, rrs, err := lookup(ctx, name, dnsTypeNS)
        if err != nil {
                return nil, err
@@ -141,7 +144,7 @@ func lookupNS(ctx context.Context, name string) ([]*NS, error) {
        return nss, nil
 }
 
-func lookupTXT(ctx context.Context, name string) ([]string, error) {
+func (r *Resolver) lookupTXT(ctx context.Context, name string) ([]string, error) {
        _, rrs, err := lookup(ctx, name, dnsTypeTXT)
        if err != nil {
                return nil, err
@@ -153,8 +156,8 @@ func lookupTXT(ctx context.Context, name string) ([]string, error) {
        return txts, nil
 }
 
-func lookupAddr(ctx context.Context, addr string) ([]string, error) {
-       if systemConf().canUseCgo() {
+func (r *Resolver) lookupAddr(ctx context.Context, addr string) ([]string, error) {
+       if !r.PreferGo && systemConf().canUseCgo() {
                if ptrs, err, ok := cgoLookupPTR(ctx, addr); ok {
                        return ptrs, err
                }

diff --git a/src/net/lookup_windows.go b/src/net/lookup_windows.go
index 5abfc844f7c4c20b87bc985794b9b6342bb0fc18..4bf748e726005b72089be014d04b92e9584b1cf4 100644 (file)
--- a/src/net/lookup_windows.go
+++ b/src/net/lookup_windows.go
@@ -54,8 +54,8 @@ func lookupProtocol(ctx context.Context, name string) (int, error) {
        }
 }
 
-func lookupHost(ctx context.Context, name string) ([]string, error) {
-       ips, err := lookupIP(ctx, name)
+func (r *Resolver) lookupHost(ctx context.Context, name string) ([]string, error) {
+       ips, err := r.lookupIP(ctx, name)
        if err != nil {
                return nil, err
        }
@@ -66,13 +66,7 @@ func lookupHost(ctx context.Context, name string) ([]string, error) {
        return addrs, nil
 }
 
-// goLookupIP isn't a Pure Go implementation on Windows.
-// TODO(bradfitz): should it be? Not sure it can be. It's always used syscall.GetAddrInfoW.
-func goLookupIP(ctx context.Context, host string) (addrs []IPAddr, err error) {
-       return lookupIP(ctx, host)
-}
-
-func lookupIP(ctx context.Context, name string) ([]IPAddr, error) {
+func (r *Resolver) lookupIP(ctx context.Context, name string) ([]IPAddr, error) {
        // TODO(bradfitz,brainman): use ctx more. See TODO below.
 
        type ret struct {
@@ -131,7 +125,11 @@ func lookupIP(ctx context.Context, name string) ([]IPAddr, error) {
        }
 }
 
-func lookupPort(ctx context.Context, network, service string) (int, error) {
+func (r *Resolver) lookupPort(ctx context.Context, network, service string) (int, error) {
+       if r.PreferGo {
+               return lookupPortMap(network, service)
+       }
+
        // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
        acquireThread()
        defer releaseThread()
@@ -171,7 +169,7 @@ func lookupPort(ctx context.Context, network, service string) (int, error) {
        return 0, &DNSError{Err: syscall.EINVAL.Error(), Name: network + "/" + service}
 }
 
-func lookupCNAME(ctx context.Context, name string) (string, error) {
+func (*Resolver) lookupCNAME(ctx context.Context, name string) (string, error) {
        // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
        acquireThread()
        defer releaseThread()
@@ -192,7 +190,7 @@ func lookupCNAME(ctx context.Context, name string) (string, error) {
        return absDomainName([]byte(cname)), nil
 }
 
-func lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) {
+func (*Resolver) lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) {
        // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
        acquireThread()
        defer releaseThread()
@@ -218,7 +216,7 @@ func lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV
        return absDomainName([]byte(target)), srvs, nil
 }
 
-func lookupMX(ctx context.Context, name string) ([]*MX, error) {
+func (*Resolver) lookupMX(ctx context.Context, name string) ([]*MX, error) {
        // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
        acquireThread()
        defer releaseThread()
@@ -238,7 +236,7 @@ func lookupMX(ctx context.Context, name string) ([]*MX, error) {
        return mxs, nil
 }
 
-func lookupNS(ctx context.Context, name string) ([]*NS, error) {
+func (*Resolver) lookupNS(ctx context.Context, name string) ([]*NS, error) {
        // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
        acquireThread()
        defer releaseThread()
@@ -257,7 +255,7 @@ func lookupNS(ctx context.Context, name string) ([]*NS, error) {
        return nss, nil
 }
 
-func lookupTXT(ctx context.Context, name string) ([]string, error) {
+func (*Resolver) lookupTXT(ctx context.Context, name string) ([]string, error) {
        // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
        acquireThread()
        defer releaseThread()
@@ -279,7 +277,7 @@ func lookupTXT(ctx context.Context, name string) ([]string, error) {
        return txts, nil
 }
 
-func lookupAddr(ctx context.Context, addr string) ([]string, error) {
+func (*Resolver) lookupAddr(ctx context.Context, addr string) ([]string, error) {
        // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
        acquireThread()
        defer releaseThread()