| // Copyright 2012 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 aix darwin dragonfly freebsd linux netbsd openbsd solaris zos |
| |
| package ipv4 |
| |
| import ( |
| "net" |
| |
| "golang.org/x/net/internal/socket" |
| ) |
| |
| // ReadFrom reads a payload of the received IPv4 datagram, from the |
| // endpoint c, copying the payload into b. It returns the number of |
| // bytes copied into b, the control message cm and the source address |
| // src of the received datagram. |
| func (c *payloadHandler) ReadFrom(b []byte) (n int, cm *ControlMessage, src net.Addr, err error) { |
| if !c.ok() { |
| return 0, nil, nil, errInvalidConn |
| } |
| c.rawOpt.RLock() |
| m := socket.Message{ |
| OOB: NewControlMessage(c.rawOpt.cflags), |
| } |
| c.rawOpt.RUnlock() |
| switch c.PacketConn.(type) { |
| case *net.UDPConn: |
| m.Buffers = [][]byte{b} |
| if err := c.RecvMsg(&m, 0); err != nil { |
| return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| } |
| case *net.IPConn: |
| h := make([]byte, HeaderLen) |
| m.Buffers = [][]byte{h, b} |
| if err := c.RecvMsg(&m, 0); err != nil { |
| return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| } |
| hdrlen := int(h[0]&0x0f) << 2 |
| if hdrlen > len(h) { |
| d := hdrlen - len(h) |
| copy(b, b[d:]) |
| m.N -= d |
| } else { |
| m.N -= hdrlen |
| } |
| default: |
| return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: errInvalidConnType} |
| } |
| if m.NN > 0 { |
| if compatFreeBSD32 { |
| adjustFreeBSD32(&m) |
| } |
| cm = new(ControlMessage) |
| if err := cm.Parse(m.OOB[:m.NN]); err != nil { |
| return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| } |
| cm.Src = netAddrToIP4(m.Addr) |
| } |
| return m.N, cm, m.Addr, nil |
| } |
| |
| // WriteTo writes a payload of the IPv4 datagram, to the destination |
| // address dst through the endpoint c, copying the payload from b. It |
| // returns the number of bytes written. The control message cm allows |
| // the datagram path and the outgoing interface to be specified. |
| // Currently only Darwin and Linux support this. The cm may be nil if |
| // control of the outgoing datagram is not required. |
| func (c *payloadHandler) WriteTo(b []byte, cm *ControlMessage, dst net.Addr) (n int, err error) { |
| if !c.ok() { |
| return 0, errInvalidConn |
| } |
| m := socket.Message{ |
| Buffers: [][]byte{b}, |
| OOB: cm.Marshal(), |
| Addr: dst, |
| } |
| err = c.SendMsg(&m, 0) |
| if err != nil { |
| err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Addr: opAddr(dst), Err: err} |
| } |
| return m.N, err |
| } |