1 files changed, 224 insertions, 0 deletions
diff --git a/src/syscall/route_bsd.go b/src/syscall/route_bsd.go
new file mode 100644
index 000000000..48af58745
--- /dev/null
+++ b/src/syscall/route_bsd.go
@@ -0,0 +1,224 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd netbsd openbsd
+
+// Routing sockets and messages
+
+package syscall
+
+import "unsafe"
+
+// Round the length of a raw sockaddr up to align it properly.
+func rsaAlignOf(salen int) int {
+	salign := sizeofPtr
+	// NOTE: It seems like 64-bit Darwin kernel still requires
+	// 32-bit aligned access to BSD subsystem. Also NetBSD 6
+	// kernel and beyond require 64-bit aligned access to routing
+	// facilities.
+	if darwin64Bit {
+		salign = 4
+	} else if netbsd32Bit {
+		salign = 8
+	}
+	if salen == 0 {
+		return salign
+	}
+	return (salen + salign - 1) & ^(salign - 1)
+}
+
+// RouteRIB returns routing information base, as known as RIB,
+// which consists of network facility information, states and
+// parameters.
+func RouteRIB(facility, param int) ([]byte, error) {
+	mib := []_C_int{CTL_NET, AF_ROUTE, 0, 0, _C_int(facility), _C_int(param)}
+	// Find size.
+	n := uintptr(0)
+	if err := sysctl(mib, nil, &n, nil, 0); err != nil {
+		return nil, err
+	}
+	if n == 0 {
+		return nil, nil
+	}
+	tab := make([]byte, n)
+	if err := sysctl(mib, &tab[0], &n, nil, 0); err != nil {
+		return nil, err
+	}
+	return tab[:n], nil
+}
+
+// RoutingMessage represents a routing message.
+type RoutingMessage interface {
+	sockaddr() []Sockaddr
+}
+
+const anyMessageLen = int(unsafe.Sizeof(anyMessage{}))
+
+type anyMessage struct {
+	Msglen  uint16
+	Version uint8
+	Type    uint8
+}
+
+// RouteMessage represents a routing message containing routing
+// entries.
+type RouteMessage struct {
+	Header RtMsghdr
+	Data   []byte
+}
+
+const rtaRtMask = RTA_DST | RTA_GATEWAY | RTA_NETMASK | RTA_GENMASK
+
+func (m *RouteMessage) sockaddr() []Sockaddr {
+	var (
+		af  int
+		sas [4]Sockaddr
+	)
+	b := m.Data[:]
+	for i := uint(0); i < RTAX_MAX; i++ {
+		if m.Header.Addrs&rtaRtMask&(1<<i) == 0 {
+			continue
+		}
+		rsa := (*RawSockaddr)(unsafe.Pointer(&b[0]))
+		switch i {
+		case RTAX_DST, RTAX_GATEWAY:
+			sa, err := anyToSockaddr((*RawSockaddrAny)(unsafe.Pointer(rsa)))
+			if err != nil {
+				return nil
+			}
+			if i == RTAX_DST {
+				af = int(rsa.Family)
+			}
+			sas[i] = sa
+		case RTAX_NETMASK, RTAX_GENMASK:
+			switch af {
+			case AF_INET:
+				rsa4 := (*RawSockaddrInet4)(unsafe.Pointer(&b[0]))
+				sa := new(SockaddrInet4)
+				for j := 0; rsa4.Len > 0 && j < int(rsa4.Len)-int(unsafe.Offsetof(rsa4.Addr)); j++ {
+					sa.Addr[j] = rsa4.Addr[j]
+				}
+				sas[i] = sa
+			case AF_INET6:
+				rsa6 := (*RawSockaddrInet6)(unsafe.Pointer(&b[0]))
+				sa := new(SockaddrInet6)
+				for j := 0; rsa6.Len > 0 && j < int(rsa6.Len)-int(unsafe.Offsetof(rsa6.Addr)); j++ {
+					sa.Addr[j] = rsa6.Addr[j]
+				}
+				sas[i] = sa
+			}
+		}
+		b = b[rsaAlignOf(int(rsa.Len)):]
+	}
+	return sas[:]
+}
+
+// InterfaceMessage represents a routing message containing
+// network interface entries.
+type InterfaceMessage struct {
+	Header IfMsghdr
+	Data   []byte
+}
+
+func (m *InterfaceMessage) sockaddr() (sas []Sockaddr) {
+	if m.Header.Addrs&RTA_IFP == 0 {
+		return nil
+	}
+	sa, err := anyToSockaddr((*RawSockaddrAny)(unsafe.Pointer(&m.Data[0])))
+	if err != nil {
+		return nil
+	}
+	return append(sas, sa)
+}
+
+// InterfaceAddrMessage represents a routing message containing
+// network interface address entries.
+type InterfaceAddrMessage struct {
+	Header IfaMsghdr
+	Data   []byte
+}
+
+const rtaIfaMask = RTA_IFA | RTA_NETMASK | RTA_BRD
+
+func (m *InterfaceAddrMessage) sockaddr() (sas []Sockaddr) {
+	if m.Header.Addrs&rtaIfaMask == 0 {
+		return nil
+	}
+	b := m.Data[:]
+	// We still see AF_UNSPEC in socket addresses on some
+	// platforms. To identify each address family correctly, we
+	// will use the address family of RTAX_NETMASK as a preferred
+	// one on the 32-bit NetBSD kernel, also use the length of
+	// RTAX_NETMASK socket address on the FreeBSD kernel.
+	preferredFamily := uint8(AF_UNSPEC)
+	for i := uint(0); i < RTAX_MAX; i++ {
+		if m.Header.Addrs&rtaIfaMask&(1<<i) == 0 {
+			continue
+		}
+		rsa := (*RawSockaddr)(unsafe.Pointer(&b[0]))
+		switch i {
+		case RTAX_IFA:
+			if rsa.Family == AF_UNSPEC {
+				rsa.Family = preferredFamily
+			}
+			sa, err := anyToSockaddr((*RawSockaddrAny)(unsafe.Pointer(rsa)))
+			if err != nil {
+				return nil
+			}
+			sas = append(sas, sa)
+		case RTAX_NETMASK:
+			switch rsa.Family {
+			case AF_UNSPEC:
+				switch rsa.Len {
+				case SizeofSockaddrInet4:
+					rsa.Family = AF_INET
+				case SizeofSockaddrInet6:
+					rsa.Family = AF_INET6
+				default:
+					rsa.Family = AF_INET // an old fashion, AF_UNSPEC means AF_INET
+				}
+			case AF_INET, AF_INET6:
+				preferredFamily = rsa.Family
+			default:
+				return nil
+			}
+			sa, err := anyToSockaddr((*RawSockaddrAny)(unsafe.Pointer(rsa)))
+			if err != nil {
+				return nil
+			}
+			sas = append(sas, sa)
+		case RTAX_BRD:
+			// nothing to do
+		}
+		b = b[rsaAlignOf(int(rsa.Len)):]
+	}
+	return sas
+}
+
+// ParseRoutingMessage parses b as routing messages and returns the
+// slice containing the RoutingMessage interfaces.
+func ParseRoutingMessage(b []byte) (msgs []RoutingMessage, err error) {
+	msgCount := 0
+	for len(b) >= anyMessageLen {
+		msgCount++
+		any := (*anyMessage)(unsafe.Pointer(&b[0]))
+		if any.Version != RTM_VERSION {
+			b = b[any.Msglen:]
+			continue
+		}
+		msgs = append(msgs, any.toRoutingMessage(b))
+		b = b[any.Msglen:]
+	}
+	// We failed to parse any of the messages - version mismatch?
+	if msgCount > 0 && len(msgs) == 0 {
+		return nil, EINVAL
+	}
+	return msgs, nil
+}
+
+// ParseRoutingMessage parses msg's payload as raw sockaddrs and
+// returns the slice containing the Sockaddr interfaces.
+func ParseRoutingSockaddr(msg RoutingMessage) (sas []Sockaddr, err error) {
+	return append(sas, msg.sockaddr()...), nil
+}