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 | |
| 7 | package ipv4 |
| 8 | |
| 9 | import ( |
| 10 | "net" |
| 11 | "runtime" |
| 12 | "syscall" |
| 13 | |
| 14 | "golang.org/x/net/internal/socket" |
| 15 | ) |
| 16 | |
| 17 | // BUG(mikio): On Windows, the ReadBatch and WriteBatch methods of |
| 18 | // PacketConn are not implemented. |
| 19 | |
| 20 | // BUG(mikio): On Windows, the ReadBatch and WriteBatch methods of |
| 21 | // RawConn are not implemented. |
| 22 | |
| 23 | // A Message represents an IO message. |
| 24 | // |
| 25 | // type Message struct { |
| 26 | // Buffers [][]byte |
| 27 | // OOB []byte |
| 28 | // Addr net.Addr |
| 29 | // N int |
| 30 | // NN int |
| 31 | // Flags int |
| 32 | // } |
| 33 | // |
| 34 | // The Buffers fields represents a list of contiguous buffers, which |
| 35 | // can be used for vectored IO, for example, putting a header and a |
| 36 | // payload in each slice. |
| 37 | // When writing, the Buffers field must contain at least one byte to |
| 38 | // write. |
| 39 | // When reading, the Buffers field will always contain a byte to read. |
| 40 | // |
| 41 | // The OOB field contains protocol-specific control or miscellaneous |
| 42 | // ancillary data known as out-of-band data. |
| 43 | // It can be nil when not required. |
| 44 | // |
| 45 | // The Addr field specifies a destination address when writing. |
| 46 | // It can be nil when the underlying protocol of the endpoint uses |
| 47 | // connection-oriented communication. |
| 48 | // After a successful read, it may contain the source address on the |
| 49 | // received packet. |
| 50 | // |
| 51 | // The N field indicates the number of bytes read or written from/to |
| 52 | // Buffers. |
| 53 | // |
| 54 | // The NN field indicates the number of bytes read or written from/to |
| 55 | // OOB. |
| 56 | // |
| 57 | // The Flags field contains protocol-specific information on the |
| 58 | // received message. |
| 59 | type Message = socket.Message |
| 60 | |
| 61 | // ReadBatch reads a batch of messages. |
| 62 | // |
| 63 | // The provided flags is a set of platform-dependent flags, such as |
| 64 | // syscall.MSG_PEEK. |
| 65 | // |
| 66 | // On a successful read it returns the number of messages received, up |
| 67 | // to len(ms). |
| 68 | // |
| 69 | // On Linux, a batch read will be optimized. |
| 70 | // On other platforms, this method will read only a single message. |
| 71 | // |
| 72 | // Unlike the ReadFrom method, it doesn't strip the IPv4 header |
| 73 | // followed by option headers from the received IPv4 datagram when the |
| 74 | // underlying transport is net.IPConn. Each Buffers field of Message |
| 75 | // must be large enough to accommodate an IPv4 header and option |
| 76 | // headers. |
| 77 | func (c *payloadHandler) ReadBatch(ms []Message, flags int) (int, error) { |
| 78 | if !c.ok() { |
| 79 | return 0, syscall.EINVAL |
| 80 | } |
| 81 | switch runtime.GOOS { |
| 82 | case "linux": |
| 83 | n, err := c.RecvMsgs([]socket.Message(ms), flags) |
| 84 | if err != nil { |
| 85 | err = &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| 86 | } |
| 87 | return n, err |
| 88 | default: |
| 89 | n := 1 |
| 90 | err := c.RecvMsg(&ms[0], flags) |
| 91 | if err != nil { |
| 92 | n = 0 |
| 93 | err = &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| 94 | } |
| 95 | return n, err |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | // WriteBatch writes a batch of messages. |
| 100 | // |
| 101 | // The provided flags is a set of platform-dependent flags, such as |
| 102 | // syscall.MSG_DONTROUTE. |
| 103 | // |
| 104 | // It returns the number of messages written on a successful write. |
| 105 | // |
| 106 | // On Linux, a batch write will be optimized. |
| 107 | // On other platforms, this method will write only a single message. |
| 108 | func (c *payloadHandler) WriteBatch(ms []Message, flags int) (int, error) { |
| 109 | if !c.ok() { |
| 110 | return 0, syscall.EINVAL |
| 111 | } |
| 112 | switch runtime.GOOS { |
| 113 | case "linux": |
| 114 | n, err := c.SendMsgs([]socket.Message(ms), flags) |
| 115 | if err != nil { |
| 116 | err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| 117 | } |
| 118 | return n, err |
| 119 | default: |
| 120 | n := 1 |
| 121 | err := c.SendMsg(&ms[0], flags) |
| 122 | if err != nil { |
| 123 | n = 0 |
| 124 | err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err} |
| 125 | } |
| 126 | return n, err |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | // ReadBatch reads a batch of messages. |
| 131 | // |
| 132 | // The provided flags is a set of platform-dependent flags, such as |
| 133 | // syscall.MSG_PEEK. |
| 134 | // |
| 135 | // On a successful read it returns the number of messages received, up |
| 136 | // to len(ms). |
| 137 | // |
| 138 | // On Linux, a batch read will be optimized. |
| 139 | // On other platforms, this method will read only a single message. |
| 140 | func (c *packetHandler) ReadBatch(ms []Message, flags int) (int, error) { |
| 141 | if !c.ok() { |
| 142 | return 0, syscall.EINVAL |
| 143 | } |
| 144 | switch runtime.GOOS { |
| 145 | case "linux": |
| 146 | n, err := c.RecvMsgs([]socket.Message(ms), flags) |
| 147 | if err != nil { |
| 148 | err = &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err} |
| 149 | } |
| 150 | return n, err |
| 151 | default: |
| 152 | n := 1 |
| 153 | err := c.RecvMsg(&ms[0], flags) |
| 154 | if err != nil { |
| 155 | n = 0 |
| 156 | err = &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err} |
| 157 | } |
| 158 | return n, err |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | // WriteBatch writes a batch of messages. |
| 163 | // |
| 164 | // The provided flags is a set of platform-dependent flags, such as |
| 165 | // syscall.MSG_DONTROUTE. |
| 166 | // |
| 167 | // It returns the number of messages written on a successful write. |
| 168 | // |
| 169 | // On Linux, a batch write will be optimized. |
| 170 | // On other platforms, this method will write only a single message. |
| 171 | func (c *packetHandler) WriteBatch(ms []Message, flags int) (int, error) { |
| 172 | if !c.ok() { |
| 173 | return 0, syscall.EINVAL |
| 174 | } |
| 175 | switch runtime.GOOS { |
| 176 | case "linux": |
| 177 | n, err := c.SendMsgs([]socket.Message(ms), flags) |
| 178 | if err != nil { |
| 179 | err = &net.OpError{Op: "write", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err} |
| 180 | } |
| 181 | return n, err |
| 182 | default: |
| 183 | n := 1 |
| 184 | err := c.SendMsg(&ms[0], flags) |
| 185 | if err != nil { |
| 186 | n = 0 |
| 187 | err = &net.OpError{Op: "write", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err} |
| 188 | } |
| 189 | return n, err |
| 190 | } |
| 191 | } |