1. Add new config CONFIG_NET_LL_GUARDSIZE to isolation of l2 stack,
which will benefit l3(IP) layer for multi-MAC(l2) implementation,
especially in some NICs such as celluler net driver.
new configuration options: CONFIG_NET_LL_GUARDSIZE
CONFIG_NET_LL_GUARDSIZE will reserved l2 buffer header size of
network buffer to isolate the L2/L3 (MAC/IP) data on network layer,
which will be beneficial to L3 network layer protocol transparent
transmission and forwarding
------------------------------------------------------------
Layout of frist iob entry:
iob_data (aligned by CONFIG_IOB_ALIGNMENT)
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| io_offset(CONFIG_NET_LL_GUARDSIZE)
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-------------------------------------------------
iob | Reserved | io_len |
-------------------------------------------------
-------------------------------------------------------------
Layout of different NICs implementation:
iob_data (aligned by CONFIG_IOB_ALIGNMENT)
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| io_offset(CONFIG_NET_LL_GUARDSIZE)
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-------------------------------------------------
Ethernet | Reserved | ETH_HDRLEN | io_len |
---------------------------------|---------------
8021Q | Reserved | ETH_8021Q_HDRLEN | io_len |
---------------------------------|---------------
ipforward | Reserved | io_len |
-------------------------------------------------
--------------------------------------------------------------------
2. Support iob offload to l2 driver to avoid unnecessary memory copy
Support send/receive iob vectors directly between the NICs and l3/l4
stack to avoid unnecessary memory copies, especially on hardware that
supports Scatter/gather, which can greatly improve performance.
new interface to support iob offload:
------------------------------------------
| IOB version | original |
|----------------------------------------|
| devif_iob_poll() | devif_poll() |
| ... | ... |
------------------------------------------
--------------------------------------------------------------------
1> NIC hardware support Scatter/gather transfer
TX:
tcp_poll()/udp_poll()/pkt_poll()/...(l3|l4)
/ \
/ \
devif_poll_[l3|l4]_connections() devif_iob_send() (nocopy:udp/icmp/...)
/ \ (copy:tcp)
/ \
devif_iob_poll("NIC"_txpoll) callback() // "NIC"_txpoll
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dev->d_iob: |
--------------- ---------------
io_data iob1 | | | iob3 | | |
\ --------------- ---------------
--------------- | --------------- |
iob0 | | | | iob2 | | | |
--------------- | --------------- |
\ | / /
\ | / /
----------------------------------------------
NICs io vector | | | | | | | | | |
----------------------------------------------
RX:
[tcp|udp|icmp|...]ipv[4|6]_data_handler()(iob_concat/append to readahead)
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[tcp|udp|icmp|...]_ipv[4|6]_in()/...
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pkt/ipv[4/6]_input()/...
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NICs io vector receive(iov_base to each iobs)
--------------------------------------------------------------------
2> CONFIG_IOB_BUFSIZE is greater than MTU:
TX:
"(CONFIG_IOB_BUFSIZE) > (MAX_NETDEV_PKTSIZE + CONFIG_NET_GUARDSIZE + CONFIG_NET_LL_GUARDSIZE)"
tcp_poll()/udp_poll()/pkt_poll()/...(l3|l4)
/ \
/ \
devif_poll_[l3|l4]_connections() devif_iob_send() (nocopy:udp/icmp/...)
/ \ (copy:tcp)
/ \
devif_iob_poll("NIC"_txpoll) callback() // "NIC"_txpoll
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"NIC"_send()
(dev->d_iob->io_data[CONFIG_NET_LL_GUARDSIZE - NET_LL_HDRLEN(dev)])
RX:
[tcp|udp|icmp|...]ipv[4|6]_data_handler()(iob_concat/append to readahead)
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[tcp|udp|icmp|...]_ipv[4|6]_in()/...
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pkt/ipv[4/6]_input()/...
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NICs io vector receive(iov_base to io_data)
--------------------------------------------------------------------
3> Compatible with all old flat buffer NICs
TX:
tcp_poll()/udp_poll()/pkt_poll()/...(l3|l4)
/ \
/ \
devif_poll_[l3|l4]_connections() devif_iob_send() (nocopy:udp/icmp/...)
/ \ (copy:tcp)
/ \
devif_iob_poll(devif_poll_callback()) devif_poll_callback() /* new interface, gather iobs to flat buffer */
/ \
/ \
devif_poll("NIC"_txpoll) "NIC"_send()(dev->d_buf)
RX:
[tcp|udp|icmp|...]ipv[4|6]_data_handler()(iob_concat/append to readahead)
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[tcp|udp|icmp|...]_ipv[4|6]_in()/...
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netdev_input() /* new interface, Scatter/gather flat/iob buffer */
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pkt/ipv[4|6]_input()/...
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NICs io vector receive(Orignal flat buffer)
3. Iperf passthrough on NuttX simulator:
-------------------------------------------------
| Protocol | Server | Client | |
|-----------------------------------------------|
| TCP | 813 | 834 | Mbits/sec |
| TCP(Offload) | 1720 | 1100 | Mbits/sec |
| UDP | 22 | 757 | Mbits/sec |
| UDP(Offload) | 25 | 1250 | Mbits/sec |
-------------------------------------------------
Signed-off-by: chao an <anchao@xiaomi.com>
79 lines
2.7 KiB
C
79 lines
2.7 KiB
C
/****************************************************************************
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* net/devif/devif_pktsend.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <string.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/net/netdev.h>
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#ifdef CONFIG_NET_PKT
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: devif_pkt_send
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*
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* Description:
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* Called from socket logic in order to send a raw packet in response to
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* an xmit or poll request from the network interface driver.
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*
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* This is almost identical to calling devif_send() except that the data to
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* be sent is copied into dev->d_buf (vs. dev->d_appdata), since there is
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* no header on the data.
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*
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* Assumptions:
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* Called with the network locked.
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*
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****************************************************************************/
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void devif_pkt_send(FAR struct net_driver_s *dev, FAR const void *buf,
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unsigned int len)
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{
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unsigned int limit = NETDEV_PKTSIZE(dev) -
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CONFIG_NET_LL_GUARDSIZE;
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if (dev == NULL || len == 0 || len > limit)
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{
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nerr("ERROR: devif_pkt_send fail: %p, sndlen: %u, pktlen: %u\n",
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dev, len, limit);
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return;
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}
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iob_update_pktlen(dev->d_iob, 0);
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/* Copy the data into the device packet buffer and set the number of
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* bytes to send
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*/
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dev->d_sndlen = iob_copyin(dev->d_iob, buf, len, 0, false) == len ?
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len : 0;
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dev->d_len = dev->d_sndlen;
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}
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#endif /* CONFIG_NET_PKT */
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