David K. Bainbridge | 215e024 | 2017-09-05 23:18:24 -0700 | [diff] [blame] | 1 | // Copyright 2017 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // +build go1.9 |
| 6 | // +build !nacl,!plan9,!windows |
| 7 | |
| 8 | package ipv4 |
| 9 | |
| 10 | import ( |
| 11 | "net" |
| 12 | |
| 13 | "golang.org/x/net/internal/socket" |
| 14 | ) |
| 15 | |
| 16 | func (c *payloadHandler) readFrom(b []byte) (int, *ControlMessage, net.Addr, error) { |
| 17 | c.rawOpt.RLock() |
| 18 | m := socket.Message{ |
| 19 | OOB: NewControlMessage(c.rawOpt.cflags), |
| 20 | } |
| 21 | c.rawOpt.RUnlock() |
| 22 | switch c.PacketConn.(type) { |
| 23 | case *net.UDPConn: |
| 24 | m.Buffers = [][]byte{b} |
| 25 | if err := c.RecvMsg(&m, 0); err != nil { |
| 26 | return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| 27 | } |
| 28 | case *net.IPConn: |
| 29 | h := make([]byte, HeaderLen) |
| 30 | m.Buffers = [][]byte{h, b} |
| 31 | if err := c.RecvMsg(&m, 0); err != nil { |
| 32 | return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| 33 | } |
| 34 | hdrlen := int(h[0]&0x0f) << 2 |
| 35 | if hdrlen > len(h) { |
| 36 | d := hdrlen - len(h) |
| 37 | copy(b, b[d:]) |
| 38 | m.N -= d |
| 39 | } else { |
| 40 | m.N -= hdrlen |
| 41 | } |
| 42 | default: |
| 43 | return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: errInvalidConnType} |
| 44 | } |
| 45 | var cm *ControlMessage |
| 46 | if m.NN > 0 { |
| 47 | cm = new(ControlMessage) |
| 48 | if err := cm.Parse(m.OOB[:m.NN]); err != nil { |
| 49 | return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| 50 | } |
| 51 | cm.Src = netAddrToIP4(m.Addr) |
| 52 | } |
| 53 | return m.N, cm, m.Addr, nil |
| 54 | } |
| 55 | |
| 56 | func (c *payloadHandler) writeTo(b []byte, cm *ControlMessage, dst net.Addr) (int, error) { |
| 57 | m := socket.Message{ |
| 58 | Buffers: [][]byte{b}, |
| 59 | OOB: cm.Marshal(), |
| 60 | Addr: dst, |
| 61 | } |
| 62 | err := c.SendMsg(&m, 0) |
| 63 | if err != nil { |
| 64 | err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Addr: opAddr(dst), Err: err} |
| 65 | } |
| 66 | return m.N, err |
| 67 | } |