| // Copyright 2016 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 |
| |
| package route |
| |
| import "runtime" |
| |
| // An Addr represents an address associated with packet routing. |
| type Addr interface { |
| // Family returns an address family. |
| Family() int |
| } |
| |
| // A LinkAddr represents a link-layer address. |
| type LinkAddr struct { |
| Index int // interface index when attached |
| Name string // interface name when attached |
| Addr []byte // link-layer address when attached |
| } |
| |
| // Family implements the Family method of Addr interface. |
| func (a *LinkAddr) Family() int { return sysAF_LINK } |
| |
| func (a *LinkAddr) lenAndSpace() (int, int) { |
| l := 8 + len(a.Name) + len(a.Addr) |
| return l, roundup(l) |
| } |
| |
| func (a *LinkAddr) marshal(b []byte) (int, error) { |
| l, ll := a.lenAndSpace() |
| if len(b) < ll { |
| return 0, errShortBuffer |
| } |
| nlen, alen := len(a.Name), len(a.Addr) |
| if nlen > 255 || alen > 255 { |
| return 0, errInvalidAddr |
| } |
| b[0] = byte(l) |
| b[1] = sysAF_LINK |
| if a.Index > 0 { |
| nativeEndian.PutUint16(b[2:4], uint16(a.Index)) |
| } |
| data := b[8:] |
| if nlen > 0 { |
| b[5] = byte(nlen) |
| copy(data[:nlen], a.Name) |
| data = data[nlen:] |
| } |
| if alen > 0 { |
| b[6] = byte(alen) |
| copy(data[:alen], a.Addr) |
| data = data[alen:] |
| } |
| return ll, nil |
| } |
| |
| func parseLinkAddr(b []byte) (Addr, error) { |
| if len(b) < 8 { |
| return nil, errInvalidAddr |
| } |
| _, a, err := parseKernelLinkAddr(sysAF_LINK, b[4:]) |
| if err != nil { |
| return nil, err |
| } |
| a.(*LinkAddr).Index = int(nativeEndian.Uint16(b[2:4])) |
| return a, nil |
| } |
| |
| // parseKernelLinkAddr parses b as a link-layer address in |
| // conventional BSD kernel form. |
| func parseKernelLinkAddr(_ int, b []byte) (int, Addr, error) { |
| // The encoding looks like the following: |
| // +----------------------------+ |
| // | Type (1 octet) | |
| // +----------------------------+ |
| // | Name length (1 octet) | |
| // +----------------------------+ |
| // | Address length (1 octet) | |
| // +----------------------------+ |
| // | Selector length (1 octet) | |
| // +----------------------------+ |
| // | Data (variable) | |
| // +----------------------------+ |
| // |
| // On some platforms, all-bit-one of length field means "don't |
| // care". |
| nlen, alen, slen := int(b[1]), int(b[2]), int(b[3]) |
| if nlen == 0xff { |
| nlen = 0 |
| } |
| if alen == 0xff { |
| alen = 0 |
| } |
| if slen == 0xff { |
| slen = 0 |
| } |
| l := 4 + nlen + alen + slen |
| if len(b) < l { |
| return 0, nil, errInvalidAddr |
| } |
| data := b[4:] |
| var name string |
| var addr []byte |
| if nlen > 0 { |
| name = string(data[:nlen]) |
| data = data[nlen:] |
| } |
| if alen > 0 { |
| addr = data[:alen] |
| data = data[alen:] |
| } |
| return l, &LinkAddr{Name: name, Addr: addr}, nil |
| } |
| |
| // An Inet4Addr represents an internet address for IPv4. |
| type Inet4Addr struct { |
| IP [4]byte // IP address |
| } |
| |
| // Family implements the Family method of Addr interface. |
| func (a *Inet4Addr) Family() int { return sysAF_INET } |
| |
| func (a *Inet4Addr) lenAndSpace() (int, int) { |
| return sizeofSockaddrInet, roundup(sizeofSockaddrInet) |
| } |
| |
| func (a *Inet4Addr) marshal(b []byte) (int, error) { |
| l, ll := a.lenAndSpace() |
| if len(b) < ll { |
| return 0, errShortBuffer |
| } |
| b[0] = byte(l) |
| b[1] = sysAF_INET |
| copy(b[4:8], a.IP[:]) |
| return ll, nil |
| } |
| |
| // An Inet6Addr represents an internet address for IPv6. |
| type Inet6Addr struct { |
| IP [16]byte // IP address |
| ZoneID int // zone identifier |
| } |
| |
| // Family implements the Family method of Addr interface. |
| func (a *Inet6Addr) Family() int { return sysAF_INET6 } |
| |
| func (a *Inet6Addr) lenAndSpace() (int, int) { |
| return sizeofSockaddrInet6, roundup(sizeofSockaddrInet6) |
| } |
| |
| func (a *Inet6Addr) marshal(b []byte) (int, error) { |
| l, ll := a.lenAndSpace() |
| if len(b) < ll { |
| return 0, errShortBuffer |
| } |
| b[0] = byte(l) |
| b[1] = sysAF_INET6 |
| copy(b[8:24], a.IP[:]) |
| if a.ZoneID > 0 { |
| nativeEndian.PutUint32(b[24:28], uint32(a.ZoneID)) |
| } |
| return ll, nil |
| } |
| |
| // parseInetAddr parses b as an internet address for IPv4 or IPv6. |
| func parseInetAddr(af int, b []byte) (Addr, error) { |
| switch af { |
| case sysAF_INET: |
| if len(b) < sizeofSockaddrInet { |
| return nil, errInvalidAddr |
| } |
| a := &Inet4Addr{} |
| copy(a.IP[:], b[4:8]) |
| return a, nil |
| case sysAF_INET6: |
| if len(b) < sizeofSockaddrInet6 { |
| return nil, errInvalidAddr |
| } |
| a := &Inet6Addr{ZoneID: int(nativeEndian.Uint32(b[24:28]))} |
| copy(a.IP[:], b[8:24]) |
| if a.IP[0] == 0xfe && a.IP[1]&0xc0 == 0x80 || a.IP[0] == 0xff && (a.IP[1]&0x0f == 0x01 || a.IP[1]&0x0f == 0x02) { |
| // KAME based IPv6 protocol stack usually |
| // embeds the interface index in the |
| // interface-local or link-local address as |
| // the kernel-internal form. |
| id := int(bigEndian.Uint16(a.IP[2:4])) |
| if id != 0 { |
| a.ZoneID = id |
| a.IP[2], a.IP[3] = 0, 0 |
| } |
| } |
| return a, nil |
| default: |
| return nil, errInvalidAddr |
| } |
| } |
| |
| // parseKernelInetAddr parses b as an internet address in conventional |
| // BSD kernel form. |
| func parseKernelInetAddr(af int, b []byte) (int, Addr, error) { |
| // The encoding looks similar to the NLRI encoding. |
| // +----------------------------+ |
| // | Length (1 octet) | |
| // +----------------------------+ |
| // | Address prefix (variable) | |
| // +----------------------------+ |
| // |
| // The differences between the kernel form and the NLRI |
| // encoding are: |
| // |
| // - The length field of the kernel form indicates the prefix |
| // length in bytes, not in bits |
| // |
| // - In the kernel form, zero value of the length field |
| // doesn't mean 0.0.0.0/0 or ::/0 |
| // |
| // - The kernel form appends leading bytes to the prefix field |
| // to make the <length, prefix> tuple to be conformed with |
| // the routing message boundary |
| l := int(b[0]) |
| if runtime.GOOS == "darwin" || runtime.GOOS == "ios" { |
| // On Darwin, an address in the kernel form is also |
| // used as a message filler. |
| if l == 0 || len(b) > roundup(l) { |
| l = roundup(l) |
| } |
| } else { |
| l = roundup(l) |
| } |
| if len(b) < l { |
| return 0, nil, errInvalidAddr |
| } |
| // Don't reorder case expressions. |
| // The case expressions for IPv6 must come first. |
| const ( |
| off4 = 4 // offset of in_addr |
| off6 = 8 // offset of in6_addr |
| ) |
| switch { |
| case b[0] == sizeofSockaddrInet6: |
| a := &Inet6Addr{} |
| copy(a.IP[:], b[off6:off6+16]) |
| return int(b[0]), a, nil |
| case af == sysAF_INET6: |
| a := &Inet6Addr{} |
| if l-1 < off6 { |
| copy(a.IP[:], b[1:l]) |
| } else { |
| copy(a.IP[:], b[l-off6:l]) |
| } |
| return int(b[0]), a, nil |
| case b[0] == sizeofSockaddrInet: |
| a := &Inet4Addr{} |
| copy(a.IP[:], b[off4:off4+4]) |
| return int(b[0]), a, nil |
| default: // an old fashion, AF_UNSPEC or unknown means AF_INET |
| a := &Inet4Addr{} |
| if l-1 < off4 { |
| copy(a.IP[:], b[1:l]) |
| } else { |
| copy(a.IP[:], b[l-off4:l]) |
| } |
| return int(b[0]), a, nil |
| } |
| } |
| |
| // A DefaultAddr represents an address of various operating |
| // system-specific features. |
| type DefaultAddr struct { |
| af int |
| Raw []byte // raw format of address |
| } |
| |
| // Family implements the Family method of Addr interface. |
| func (a *DefaultAddr) Family() int { return a.af } |
| |
| func (a *DefaultAddr) lenAndSpace() (int, int) { |
| l := len(a.Raw) |
| return l, roundup(l) |
| } |
| |
| func (a *DefaultAddr) marshal(b []byte) (int, error) { |
| l, ll := a.lenAndSpace() |
| if len(b) < ll { |
| return 0, errShortBuffer |
| } |
| if l > 255 { |
| return 0, errInvalidAddr |
| } |
| b[1] = byte(l) |
| copy(b[:l], a.Raw) |
| return ll, nil |
| } |
| |
| func parseDefaultAddr(b []byte) (Addr, error) { |
| if len(b) < 2 || len(b) < int(b[0]) { |
| return nil, errInvalidAddr |
| } |
| a := &DefaultAddr{af: int(b[1]), Raw: b[:b[0]]} |
| return a, nil |
| } |
| |
| func addrsSpace(as []Addr) int { |
| var l int |
| for _, a := range as { |
| switch a := a.(type) { |
| case *LinkAddr: |
| _, ll := a.lenAndSpace() |
| l += ll |
| case *Inet4Addr: |
| _, ll := a.lenAndSpace() |
| l += ll |
| case *Inet6Addr: |
| _, ll := a.lenAndSpace() |
| l += ll |
| case *DefaultAddr: |
| _, ll := a.lenAndSpace() |
| l += ll |
| } |
| } |
| return l |
| } |
| |
| // marshalAddrs marshals as and returns a bitmap indicating which |
| // address is stored in b. |
| func marshalAddrs(b []byte, as []Addr) (uint, error) { |
| var attrs uint |
| for i, a := range as { |
| switch a := a.(type) { |
| case *LinkAddr: |
| l, err := a.marshal(b) |
| if err != nil { |
| return 0, err |
| } |
| b = b[l:] |
| attrs |= 1 << uint(i) |
| case *Inet4Addr: |
| l, err := a.marshal(b) |
| if err != nil { |
| return 0, err |
| } |
| b = b[l:] |
| attrs |= 1 << uint(i) |
| case *Inet6Addr: |
| l, err := a.marshal(b) |
| if err != nil { |
| return 0, err |
| } |
| b = b[l:] |
| attrs |= 1 << uint(i) |
| case *DefaultAddr: |
| l, err := a.marshal(b) |
| if err != nil { |
| return 0, err |
| } |
| b = b[l:] |
| attrs |= 1 << uint(i) |
| } |
| } |
| return attrs, nil |
| } |
| |
| func parseAddrs(attrs uint, fn func(int, []byte) (int, Addr, error), b []byte) ([]Addr, error) { |
| var as [sysRTAX_MAX]Addr |
| af := int(sysAF_UNSPEC) |
| for i := uint(0); i < sysRTAX_MAX && len(b) >= roundup(0); i++ { |
| if attrs&(1<<i) == 0 { |
| continue |
| } |
| if i <= sysRTAX_BRD { |
| switch b[1] { |
| case sysAF_LINK: |
| a, err := parseLinkAddr(b) |
| if err != nil { |
| return nil, err |
| } |
| as[i] = a |
| l := roundup(int(b[0])) |
| if len(b) < l { |
| return nil, errMessageTooShort |
| } |
| b = b[l:] |
| case sysAF_INET, sysAF_INET6: |
| af = int(b[1]) |
| a, err := parseInetAddr(af, b) |
| if err != nil { |
| return nil, err |
| } |
| as[i] = a |
| l := roundup(int(b[0])) |
| if len(b) < l { |
| return nil, errMessageTooShort |
| } |
| b = b[l:] |
| default: |
| l, a, err := fn(af, b) |
| if err != nil { |
| return nil, err |
| } |
| as[i] = a |
| ll := roundup(l) |
| if len(b) < ll { |
| b = b[l:] |
| } else { |
| b = b[ll:] |
| } |
| } |
| } else { |
| a, err := parseDefaultAddr(b) |
| if err != nil { |
| return nil, err |
| } |
| as[i] = a |
| l := roundup(int(b[0])) |
| if len(b) < l { |
| return nil, errMessageTooShort |
| } |
| b = b[l:] |
| } |
| } |
| return as[:], nil |
| } |