79 lines
1.9 KiB
Markdown
79 lines
1.9 KiB
Markdown
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# Semihost
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Semihost is used when host implements lwip at its own, and firmware takes response of 802.11 SME/MLME, all its network frames except EAPoL frames are passed up to host.
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## Usage
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### Firmware
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* modify `CFG_HOSTED=CONFIG_SEMI_HOSTED` in `sys_config_bk7231u.h`.
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```c
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/* Host based SDIO/USB/PCI/SPI Wifi Support */
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/* fully hosted: no lwip, all mgmt located at host */
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#define CONFIG_FULLY_HOSTED 1
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/* semi hosted: no lwip, all mgmt located at host */
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#define CONFIG_SEMI_HOSTED 2
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/* CFG_HOSTED: 0 disabled, CONFIG_FULLY_HOSTED, CONFIG_SEMI_HOSTED */
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#define CFG_HOSTED CONFIG_SEMI_HOSTED
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```
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* compile
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```sh
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$ make bk7231u -j8 # add V=1 to show verbose log
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```
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* burn firmware via GUI or CLI
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* run firmware
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It's high recommended to change the default mac address, now login into the demo board.
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```shell
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# mac c8478c723101 # change mac address to c8:47:8c:72:31:01
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```
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### Host
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This demo only runs on Linux. MacOS may also works.
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* compile serial-tap
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```shell
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$ cd tools/semihost/serial-tap
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$ cmake .
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$ make
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```
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This will generate an excutable binary named `serial_tun`.
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* setup a tap device
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```shell
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$ sudo ./setup-tapif # add a tap0 network adapter
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$ sudo ip link set address c8:47:8c:72:31:01 dev tap0 # set tap0's mac address equals to firmware
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$ sudo ./serial_tun -i tap0 -p /dev/ttyUSB0
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```
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If acts as a softap, you must change tap0's mac address the same as softap's mac address, and setup a dhcp server. For example, udhcpd can be used.
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```
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$ sudo udhcpd udhcpd.conf # setup an dhcp server
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```
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### Limitation
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Now `UART` is used as the physical layer, and the throughput is very low due to UART's low rate.
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## Debug
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* Tools such as wireshark, tcpdump can be used to analysis packet at link layer.
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* TAP devices' mac address must equal to firmware's mac address
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