internal/routebsd: simplify for standard library

Discard everything we don't need from x/net/route.

Change-Id: If6a4ecb37e5e2349bc4df46c151990719a14f2c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/637696
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>

4 files changed, 42 insertions, 51 deletions

diff --git a/src/net/interface_bsd.go b/src/net/interface_bsd.go
index 687af00170..0861610f16 100644
--- a/src/net/interface_bsd.go
+++ b/src/net/interface_bsd.go
@@ -38,12 +38,7 @@ func interfaceTable(ifindex int) ([]Interface, error) {
 				ift[n].HardwareAddr = make([]byte, len(sa.Addr))
 				copy(ift[n].HardwareAddr, sa.Addr)
 			}
-			for _, sys := range m.Sys() {
-				if imx, ok := sys.(*routebsd.InterfaceMetrics); ok {
-					ift[n].MTU = imx.MTU
-					break
-				}
-			}
+			ift[n].MTU = m.MTU()
 			n++
 			if ifindex == m.Index {
 				return ift[:n], nil
@@ -97,19 +92,27 @@ func interfaceAddrTable(ifi *Interface) ([]Addr, error) {
 			}
 			var mask IPMask
 			switch sa := m.Addrs[syscall.RTAX_NETMASK].(type) {
-			case *routebsd.Inet4Addr:
-				mask = IPv4Mask(sa.IP[0], sa.IP[1], sa.IP[2], sa.IP[3])
-			case *routebsd.Inet6Addr:
-				mask = make(IPMask, IPv6len)
-				copy(mask, sa.IP[:])
+			case *routebsd.InetAddr:
+				if sa.IP.Is4() {
+					a := sa.IP.As4()
+					mask = IPv4Mask(a[0], a[1], a[2], a[3])
+				} else if sa.IP.Is6() {
+					a := sa.IP.As16()
+					mask = make(IPMask, IPv6len)
+					copy(mask, a[:])
+				}
 			}
 			var ip IP
 			switch sa := m.Addrs[syscall.RTAX_IFA].(type) {
-			case *routebsd.Inet4Addr:
-				ip = IPv4(sa.IP[0], sa.IP[1], sa.IP[2], sa.IP[3])
-			case *routebsd.Inet6Addr:
-				ip = make(IP, IPv6len)
-				copy(ip, sa.IP[:])
+			case *routebsd.InetAddr:
+				if sa.IP.Is4() {
+					a := sa.IP.As4()
+					ip = IPv4(a[0], a[1], a[2], a[3])
+				} else if sa.IP.Is6() {
+					a := sa.IP.As16()
+					ip = make(IP, IPv6len)
+					copy(ip, a[:])
+				}
 			}
 			if ip != nil && mask != nil { // NetBSD may contain routebsd.LinkAddr
 				ifat = append(ifat, &IPNet{IP: ip, Mask: mask})
diff --git a/src/net/interface_bsdvar.go b/src/net/interface_bsdvar.go
index 3946921232..dc6c293a8e 100644
--- a/src/net/interface_bsdvar.go
+++ b/src/net/interface_bsdvar.go
@@ -12,11 +12,7 @@ import (
 )
 
 func interfaceMessages(ifindex int) ([]routebsd.Message, error) {
-	rib, err := routebsd.FetchRIB(syscall.AF_UNSPEC, syscall.NET_RT_IFLIST, ifindex)
-	if err != nil {
-		return nil, err
-	}
-	return routebsd.ParseRIB(syscall.NET_RT_IFLIST, rib)
+	return routebsd.FetchRIBMessages(syscall.NET_RT_IFLIST, ifindex)
 }
 
 // interfaceMulticastAddrTable returns addresses for a specific
diff --git a/src/net/interface_darwin.go b/src/net/interface_darwin.go
index 45f1363025..95c44e68e6 100644
--- a/src/net/interface_darwin.go
+++ b/src/net/interface_darwin.go
@@ -10,21 +10,13 @@ import (
 )
 
 func interfaceMessages(ifindex int) ([]routebsd.Message, error) {
-	rib, err := routebsd.FetchRIB(syscall.AF_UNSPEC, syscall.NET_RT_IFLIST, ifindex)
-	if err != nil {
-		return nil, err
-	}
-	return routebsd.ParseRIB(syscall.NET_RT_IFLIST, rib)
+	return routebsd.FetchRIBMessages(syscall.NET_RT_IFLIST, ifindex)
 }
 
 // interfaceMulticastAddrTable returns addresses for a specific
 // interface.
 func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
-	rib, err := routebsd.FetchRIB(syscall.AF_UNSPEC, syscall.NET_RT_IFLIST2, ifi.Index)
-	if err != nil {
-		return nil, err
-	}
-	msgs, err := routebsd.ParseRIB(syscall.NET_RT_IFLIST2, rib)
+	msgs, err := routebsd.FetchRIBMessages(syscall.NET_RT_IFLIST2, ifi.Index)
 	if err != nil {
 		return nil, err
 	}
@@ -37,11 +29,15 @@ func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
 			}
 			var ip IP
 			switch sa := m.Addrs[syscall.RTAX_IFA].(type) {
-			case *routebsd.Inet4Addr:
-				ip = IPv4(sa.IP[0], sa.IP[1], sa.IP[2], sa.IP[3])
-			case *routebsd.Inet6Addr:
-				ip = make(IP, IPv6len)
-				copy(ip, sa.IP[:])
+			case *routebsd.InetAddr:
+				if sa.IP.Is4() {
+					a := sa.IP.As4()
+					ip = IPv4(a[0], a[1], a[2], a[3])
+				} else if sa.IP.Is6() {
+					a := sa.IP.As16()
+					ip = make(IP, IPv6len)
+					copy(ip, a[:])
+				}
 			}
 			if ip != nil {
 				ifmat = append(ifmat, &IPAddr{IP: ip})
diff --git a/src/net/interface_freebsd.go b/src/net/interface_freebsd.go
index fda7a86a2f..301faa47ba 100644
--- a/src/net/interface_freebsd.go
+++ b/src/net/interface_freebsd.go
@@ -10,21 +10,13 @@ import (
 )
 
 func interfaceMessages(ifindex int) ([]routebsd.Message, error) {
-	rib, err := routebsd.FetchRIB(syscall.AF_UNSPEC, routebsd.RIBTypeInterface, ifindex)
-	if err != nil {
-		return nil, err
-	}
-	return routebsd.ParseRIB(routebsd.RIBTypeInterface, rib)
+	return routebsd.FetchRIBMessages(syscall.NET_RT_IFLIST, ifindex)
 }
 
 // interfaceMulticastAddrTable returns addresses for a specific
 // interface.
 func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
-	rib, err := routebsd.FetchRIB(syscall.AF_UNSPEC, syscall.NET_RT_IFMALIST, ifi.Index)
-	if err != nil {
-		return nil, err
-	}
-	msgs, err := routebsd.ParseRIB(syscall.NET_RT_IFMALIST, rib)
+	msgs, err := routebsd.FetchRIBMessages(syscall.NET_RT_IFMALIST, ifi.Index)
 	if err != nil {
 		return nil, err
 	}
@@ -37,11 +29,15 @@ func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
 			}
 			var ip IP
 			switch sa := m.Addrs[syscall.RTAX_IFA].(type) {
-			case *routebsd.Inet4Addr:
-				ip = IPv4(sa.IP[0], sa.IP[1], sa.IP[2], sa.IP[3])
-			case *routebsd.Inet6Addr:
-				ip = make(IP, IPv6len)
-				copy(ip, sa.IP[:])
+			case *routebsd.InetAddr:
+				if sa.IP.Is4() {
+					a := sa.IP.As4()
+					ip = IPv4(a[0], a[1], a[2], a[3])
+				} else if sa.IP.Is6() {
+					a := sa.IP.As16()
+					ip = make(IP, IPv6len)
+					copy(ip, a[:])
+				}
 			}
 			if ip != nil {
 				ifmat = append(ifmat, &IPAddr{IP: ip})