96 lines
2.3 KiB
Go
96 lines
2.3 KiB
Go
|
/*
|
||
|
|
*------------------------------------------------------------------
|
||
|
|
* Copyright (c) 2020 Cisco and/or its affiliates.
|
||
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
* you may not use this file except in compliance with the License.
|
||
|
|
* You may obtain a copy of the License at:
|
||
|
|
*
|
||
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
*
|
||
|
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
* See the License for the specific language governing permissions and
|
||
|
|
* limitations under the License.
|
||
|
|
*------------------------------------------------------------------
|
||
|
|
*/
|
||
|
|
|
||
|
|
package memif
|
||
|
|
|
||
|
|
// WritePacket writes one packet to the shared memory and
|
||
|
|
// returns the number of bytes written
|
||
|
|
func (q *Queue) WritePacket(pkt []byte) int {
|
||
|
|
var mask int = q.ring.size - 1
|
||
|
|
var slot int
|
||
|
|
var nFree uint16
|
||
|
|
var packetBufferSize int = int(q.i.run.PacketBufferSize)
|
||
|
|
|
||
|
|
if q.i.args.IsMaster {
|
||
|
|
slot = q.readTail()
|
||
|
|
nFree = uint16(q.readHead() - slot)
|
||
|
|
} else {
|
||
|
|
slot = q.readHead()
|
||
|
|
nFree = uint16(q.ring.size - slot + q.readTail())
|
||
|
|
}
|
||
|
|
|
||
|
|
if nFree == 0 {
|
||
|
|
q.interrupt()
|
||
|
|
return 0
|
||
|
|
}
|
||
|
|
|
||
|
|
// copy descriptor from shm
|
||
|
|
desc := newDescBuf()
|
||
|
|
q.getDescBuf(slot&mask, desc)
|
||
|
|
// reset flags
|
||
|
|
desc.setFlags(0)
|
||
|
|
// reset length
|
||
|
|
if q.i.args.IsMaster {
|
||
|
|
packetBufferSize = desc.getLength()
|
||
|
|
}
|
||
|
|
desc.setLength(0)
|
||
|
|
offset := desc.getOffset()
|
||
|
|
|
||
|
|
// write packet into memif buffer
|
||
|
|
n := copy(q.i.regions[desc.getRegion()].data[offset:offset+packetBufferSize], pkt[:])
|
||
|
|
desc.setLength(n)
|
||
|
|
for n < len(pkt) {
|
||
|
|
nFree--
|
||
|
|
if nFree == 0 {
|
||
|
|
q.interrupt()
|
||
|
|
return 0
|
||
|
|
}
|
||
|
|
desc.setFlags(descFlagNext)
|
||
|
|
q.putDescBuf(slot&mask, desc)
|
||
|
|
slot++
|
||
|
|
|
||
|
|
// copy descriptor from shm
|
||
|
|
q.getDescBuf(slot&mask, desc)
|
||
|
|
// reset flags
|
||
|
|
desc.setFlags(0)
|
||
|
|
// reset length
|
||
|
|
if q.i.args.IsMaster {
|
||
|
|
packetBufferSize = desc.getLength()
|
||
|
|
}
|
||
|
|
desc.setLength(0)
|
||
|
|
offset := desc.getOffset()
|
||
|
|
|
||
|
|
tmp := copy(q.i.regions[desc.getRegion()].data[offset:offset+packetBufferSize], pkt[:])
|
||
|
|
desc.setLength(tmp)
|
||
|
|
n += tmp
|
||
|
|
}
|
||
|
|
|
||
|
|
// copy descriptor to shm
|
||
|
|
q.putDescBuf(slot&mask, desc)
|
||
|
|
slot++
|
||
|
|
|
||
|
|
if q.i.args.IsMaster {
|
||
|
|
q.writeTail(slot)
|
||
|
|
} else {
|
||
|
|
q.writeHead(slot)
|
||
|
|
}
|
||
|
|
|
||
|
|
q.interrupt()
|
||
|
|
|
||
|
|
return n
|
||
|
|
}
|