net: fix inconsistent error values on Interface

This change fixes inconsistent error values on Interfaces,
InterfaceAddrs, InterfaceBy{Index,Name}, and Addrs and MulticastAddrs
methods of Interface.

Updates #4856.

Change-Id: I09e65522a22f45c641792d774ebf7a0081b874ad
Reviewed-on: https://go-review.googlesource.com/9140Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/net/interface.go

@@ -62,41 +62,61 @@ func (f Flags) String() string {
 // Addrs returns interface addresses for a specific interface.
 func (ifi *Interface) Addrs() ([]Addr, error) {
 	if ifi == nil {
-		return nil, errInvalidInterface
+		return nil, &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: errInvalidInterface}
 	}
-	return interfaceAddrTable(ifi)
+	ifat, err := interfaceAddrTable(ifi)
+	if err != nil {
+		err = &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: err}
+	}
+	return ifat, err
 }
 
 // MulticastAddrs returns multicast, joined group addresses for
 // a specific interface.
 func (ifi *Interface) MulticastAddrs() ([]Addr, error) {
 	if ifi == nil {
-		return nil, errInvalidInterface
+		return nil, &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: errInvalidInterface}
+	}
+	ifat, err := interfaceMulticastAddrTable(ifi)
+	if err != nil {
+		err = &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: err}
 	}
-	return interfaceMulticastAddrTable(ifi)
+	return ifat, err
 }
 
 // Interfaces returns a list of the system's network interfaces.
 func Interfaces() ([]Interface, error) {
-	return interfaceTable(0)
+	ift, err := interfaceTable(0)
+	if err != nil {
+		err = &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: err}
+	}
+	return ift, err
 }
 
 // InterfaceAddrs returns a list of the system's network interface
 // addresses.
 func InterfaceAddrs() ([]Addr, error) {
-	return interfaceAddrTable(nil)
+	ifat, err := interfaceAddrTable(nil)
+	if err != nil {
+		err = &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: err}
+	}
+	return ifat, err
 }
 
 // InterfaceByIndex returns the interface specified by index.
 func InterfaceByIndex(index int) (*Interface, error) {
 	if index <= 0 {
-		return nil, errInvalidInterfaceIndex
+		return nil, &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: errInvalidInterfaceIndex}
 	}
 	ift, err := interfaceTable(index)
 	if err != nil {
-		return nil, err
+		return nil, &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: err}
 	}
-	return interfaceByIndex(ift, index)
+	ifi, err := interfaceByIndex(ift, index)
+	if err != nil {
+		err = &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: err}
+	}
+	return ifi, err
 }
 
 func interfaceByIndex(ift []Interface, index int) (*Interface, error) {
@@ -111,16 +131,16 @@ func interfaceByIndex(ift []Interface, index int) (*Interface, error) {
 // InterfaceByName returns the interface specified by name.
 func InterfaceByName(name string) (*Interface, error) {
 	if name == "" {
-		return nil, errInvalidInterfaceName
+		return nil, &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: errInvalidInterfaceName}
 	}
 	ift, err := interfaceTable(0)
 	if err != nil {
-		return nil, err
+		return nil, &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: err}
 	}
 	for _, ifi := range ift {
 		if name == ifi.Name {
 			return &ifi, nil
 		}
 	}
-	return nil, errNoSuchInterface
+	return nil, &OpError{Op: "route", Net: "ip+net", Addr: nil, Err: errNoSuchInterface}
 }

src/net/interface_bsd.go

@@ -7,7 +7,6 @@
 package net
 
 import (
-	"os"
 	"syscall"
 	"unsafe"
 )
@@ -18,11 +17,11 @@ import (
 func interfaceTable(ifindex int) ([]Interface, error) {
 	tab, err := syscall.RouteRIB(syscall.NET_RT_IFLIST, ifindex)
 	if err != nil {
-		return nil, os.NewSyscallError("route rib", err)
+		return nil, err
 	}
 	msgs, err := syscall.ParseRoutingMessage(tab)
 	if err != nil {
-		return nil, os.NewSyscallError("route message", err)
+		return nil, err
 	}
 	return parseInterfaceTable(ifindex, msgs)
 }
@@ -51,7 +50,7 @@ loop:
 func newLink(m *syscall.InterfaceMessage) (*Interface, error) {
 	sas, err := syscall.ParseRoutingSockaddr(m)
 	if err != nil {
-		return nil, os.NewSyscallError("route sockaddr", err)
+		return nil, err
 	}
 	ifi := &Interface{Index: int(m.Header.Index), Flags: linkFlags(m.Header.Flags)}
 	sa, _ := sas[syscall.RTAX_IFP].(*syscall.SockaddrDatalink)
@@ -104,11 +103,11 @@ func interfaceAddrTable(ifi *Interface) ([]Addr, error) {
 	}
 	tab, err := syscall.RouteRIB(syscall.NET_RT_IFLIST, index)
 	if err != nil {
-		return nil, os.NewSyscallError("route rib", err)
+		return nil, err
 	}
 	msgs, err := syscall.ParseRoutingMessage(tab)
 	if err != nil {
-		return nil, os.NewSyscallError("route message", err)
+		return nil, err
 	}
 	var ift []Interface
 	if index == 0 {
@@ -145,7 +144,7 @@ func interfaceAddrTable(ifi *Interface) ([]Addr, error) {
 func newAddr(ifi *Interface, m *syscall.InterfaceAddrMessage) (*IPNet, error) {
 	sas, err := syscall.ParseRoutingSockaddr(m)
 	if err != nil {
-		return nil, os.NewSyscallError("route sockaddr", err)
+		return nil, err
 	}
 	ifa := &IPNet{}
 	switch sa := sas[syscall.RTAX_NETMASK].(type) {

src/net/interface_darwin.go

@@ -4,21 +4,18 @@
 
 package net
 
-import (
-	"os"
-	"syscall"
-)
+import "syscall"
 
 // interfaceMulticastAddrTable returns addresses for a specific
 // interface.
 func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
 	tab, err := syscall.RouteRIB(syscall.NET_RT_IFLIST2, ifi.Index)
 	if err != nil {
-		return nil, os.NewSyscallError("route rib", err)
+		return nil, err
 	}
 	msgs, err := syscall.ParseRoutingMessage(tab)
 	if err != nil {
-		return nil, os.NewSyscallError("route message", err)
+		return nil, err
 	}
 	var ifmat []Addr
 	for _, m := range msgs {
@@ -41,7 +38,7 @@ func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
 func newMulticastAddr(ifi *Interface, m *syscall.InterfaceMulticastAddrMessage) (*IPAddr, error) {
 	sas, err := syscall.ParseRoutingSockaddr(m)
 	if err != nil {
-		return nil, os.NewSyscallError("route sockaddr", err)
+		return nil, err
 	}
 	switch sa := sas[syscall.RTAX_IFA].(type) {
 	case *syscall.SockaddrInet4:

src/net/interface_freebsd.go

@@ -4,21 +4,18 @@
 
 package net
 
-import (
-	"os"
-	"syscall"
-)
+import "syscall"
 
 // interfaceMulticastAddrTable returns addresses for a specific
 // interface.
 func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
 	tab, err := syscall.RouteRIB(syscall.NET_RT_IFMALIST, ifi.Index)
 	if err != nil {
-		return nil, os.NewSyscallError("route rib", err)
+		return nil, err
 	}
 	msgs, err := syscall.ParseRoutingMessage(tab)
 	if err != nil {
-		return nil, os.NewSyscallError("route message", err)
+		return nil, err
 	}
 	var ifmat []Addr
 	for _, m := range msgs {
@@ -41,7 +38,7 @@ func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
 func newMulticastAddr(ifi *Interface, m *syscall.InterfaceMulticastAddrMessage) (*IPAddr, error) {
 	sas, err := syscall.ParseRoutingSockaddr(m)
 	if err != nil {
-		return nil, os.NewSyscallError("route sockaddr", err)
+		return nil, err
 	}
 	switch sa := sas[syscall.RTAX_IFA].(type) {
 	case *syscall.SockaddrInet4:

src/net/interface_linux.go

@@ -5,7 +5,6 @@
 package net
 
 import (
-	"os"
 	"syscall"
 	"unsafe"
 )
@@ -16,11 +15,11 @@ import (
 func interfaceTable(ifindex int) ([]Interface, error) {
 	tab, err := syscall.NetlinkRIB(syscall.RTM_GETLINK, syscall.AF_UNSPEC)
 	if err != nil {
-		return nil, os.NewSyscallError("netlink rib", err)
+		return nil, err
 	}
 	msgs, err := syscall.ParseNetlinkMessage(tab)
 	if err != nil {
-		return nil, os.NewSyscallError("netlink message", err)
+		return nil, err
 	}
 	var ift []Interface
 loop:
@@ -33,7 +32,7 @@ loop:
 			if ifindex == 0 || ifindex == int(ifim.Index) {
 				attrs, err := syscall.ParseNetlinkRouteAttr(&m)
 				if err != nil {
-					return nil, os.NewSyscallError("netlink routeattr", err)
+					return nil, err
 				}
 				ift = append(ift, *newLink(ifim, attrs))
 				if ifindex == int(ifim.Index) {
@@ -120,11 +119,11 @@ func linkFlags(rawFlags uint32) Flags {
 func interfaceAddrTable(ifi *Interface) ([]Addr, error) {
 	tab, err := syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
 	if err != nil {
-		return nil, os.NewSyscallError("netlink rib", err)
+		return nil, err
 	}
 	msgs, err := syscall.ParseNetlinkMessage(tab)
 	if err != nil {
-		return nil, os.NewSyscallError("netlink message", err)
+		return nil, err
 	}
 	var ift []Interface
 	if ifi == nil {
@@ -160,7 +159,7 @@ loop:
 				}
 				attrs, err := syscall.ParseNetlinkRouteAttr(&m)
 				if err != nil {
-					return nil, os.NewSyscallError("netlink routeattr", err)
+					return nil, err
 				}
 				ifa := newAddr(ifi, ifam, attrs)
 				if ifa != nil {

src/net/interface_windows.go

@@ -6,7 +6,6 @@ package net
 
 import (
 	"internal/syscall/windows"
-	"os"
 	"syscall"
 	"unsafe"
 )
@@ -27,7 +26,7 @@ func getAdapters() (*windows.IpAdapterAddresses, error) {
 			break
 		}
 		if err.(syscall.Errno) != syscall.ERROR_BUFFER_OVERFLOW {
-			return nil, os.NewSyscallError("GetAdaptersAddresses", err)
+			return nil, err
 		}
 	}
 	return &addrs[0], nil
@@ -36,16 +35,16 @@ func getAdapters() (*windows.IpAdapterAddresses, error) {
 func getInterfaceInfos() ([]syscall.InterfaceInfo, error) {
 	s, err := sysSocket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP)
 	if err != nil {
-		return nil, os.NewSyscallError("Socket", err)
+		return nil, err
 	}
-	defer syscall.Closesocket(s)
+	defer closeFunc(s)
 
 	iia := [20]syscall.InterfaceInfo{}
 	ret := uint32(0)
 	size := uint32(unsafe.Sizeof(iia))
 	err = syscall.WSAIoctl(s, syscall.SIO_GET_INTERFACE_LIST, nil, 0, (*byte)(unsafe.Pointer(&iia[0])), size, &ret, nil, 0)
 	if err != nil {
-		return nil, os.NewSyscallError("WSAIoctl", err)
+		return nil, err
 	}
 	iilen := ret / uint32(unsafe.Sizeof(iia[0]))
 	return iia[:iilen-1], nil