ENC28J60 adalah pengontrol Ethernet sederhana yang dapat bertindak sebagai kartu jaringan eksternal untuk komputer papan tunggal dengan GPIO (bahkan ada driver siap pakai untuk raspberry) dan arduins lainnya. GPIO tidak ditampilkan di laptop saya, mari coba perbaiki cacat ini dan kencangkan ENC28J60 menggunakan STM32F103 dan tali pengikat USB.
Mari kita lihat bagaimana Anda bisa melakukan ini.
Kita butuh:
ENC28J60
Papan debug dengan STM32 dengan dukungan perangkat USB (misalnya, yang ini):
Linux ( Ubuntu 16)
Ethernet ( raspberry pi), wi-fi ( )
STM32F103 , . ENC28J60 ( c ). ENC28J60 STM32F103 SPI1 .
(usb) -> stm32(SPI) -> ENC28J60(Ethernet ) -> raspberry
, user space. tap ( , Ethernet , tun , ip ), ( tap_handler.c). Linux, tap_handler' tap . , , tap , tap_handler', - . , tap_handler tap , /dev/ttyACM0 ( USB Linux). /dev/ttyACM0, tap .
STM32 CubeMX USB CDC (virtual com port). SMT32 Linux /dev/ttyACM0 ( ). , STM32, , STM32.
STM32 . ( CDC_Receive_FS
usbd_cdc_if.c) ENC28J60, , ENC28J60 CDC_Transmit_FS
.
, CDC . , . , ( , wireshark usb). , - - STM32, , .. . .
:
sudo openvpn --mktun --dev tap0
ip :
sudo ifconfig tap0 10.0.0.1/24 up
tap_handler.
/dev/ttyACM0 raw (, .). :
char cdc_name[20]="/dev/ttyACM0";
int tty_fd = open(cdc_name, O_RDWR | O_NOCTTY);
struct termios portSettings;
tcgetattr(tty_fd, &portSettings);
cfmakeraw(&portSettings);
tcsetattr(tty_fd, TCSANOW, &portSettings);
tcflush(tty_fd, TCOFLUSH);
tap_handler tap0:
/* dev tap0*/
int tun_alloc(char *dev, int flags) {
struct ifreq ifr;
int fd, err;
char *clonedev = "/dev/net/tun";
/* /dev/net/tun */
if( (fd = open(clonedev , O_RDWR)) < 0 ) {
perror("Opening /dev/net/tun");
return fd;
}
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = flags;
/* tap0 */
if (*dev) {
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
}
/* */
if( (err = ioctl(fd, TUNSETIFF, (void *)&ifr)) < 0 ) {
perror("ioctl(TUNSETIFF)");
close(fd);
return err;
}
strcpy(dev, ifr.ifr_name);
return fd;
}
main.c :
strcpy(tun_name, "tap0");
int tap_fd = tun_alloc(tun_name, IFF_TAP | IFF_NO_PI);
IFF_TAP (tap). IFF_NO_PI , .
tap0 /dev/ttyACM0. , tap_handler select:
while(1) {
int ret;
fd_set rd_set;
FD_ZERO(&rd_set);
/* tap_fd - tap inteface descriptor */
FD_SET(tap_fd, &rd_set);
/* tty_fd - /dev/ttyACM0 descriptor */
FD_SET(tty_fd, &rd_set);
ret = select(maxfd + 1, &rd_set, NULL, NULL, NULL);
. tap0 tap_handler STM32 ( : - 4 , , 2 - , ) /dev/ttyACM0. , :
if(FD_ISSET(tap_fd, &rd_set)) {
uint16_t nread = cread(tap_fd, buffer, BUFSIZE);
uint8_t buf[6];
*(uint32_t *)buf = PACKET_START_SIGN;
*(uint16_t *)(buf + 4) = nread;
cwrite(tty_fd,(char *)buf,6);
cwrite(tty_fd, buffer, nread);
delay_micro(delay_m);
}
/dev/ttyACM0, ( 4 ), , . tap :
if(FD_ISSET(tty_fd, &rd_set)) {
uint32_t sign;
/* */
int nread = read_n(tty_fd, (char *)&sign, sizeof(sign));
/* , */
if(nread == 0) {
break;
}
/* , 4 */
if(sign != PACKET_START_SIGN){
continue;
}
/* */
nread = read_n(tty_fd, (char *)&plength, 2);
if(nread == 0) {
break;
}
if (nread != 2){
continue;
}
/* , */
if(flag){
flag = 0;
nread = cread(tty_fd, buffer, sizeof(buffer));
if(nread != 6){
continue;
}
}
/* , */
if(plength > BUFSIZE){
break;
}
/* (plength ) tap interface*/
nread = read_n(tty_fd, buffer, plength);
if (nread != 0){
cwrite(tap_fd, buffer, nread);
delay_micro(delay_m);
}
}
STM32
USB CDC CubeMX HAL SPI1 .
callback' CDC_Receive_FS
( usbd_cdc_if.c), USB. , , ENC28J60. :
/* USB_POINTERS_ARRAY_SIZE - array_pos */
/* MAX_FRAMELEN - */
/* USB_BUFSIZE - */
extern uint8_t usb_buf[]; /* */
extern uint32_t pos_int; /* */
extern uint32_t array_pos[]; /* , */
extern uint32_t p_a; /* array_pos CDC_Receive_FS*/
extern uint32_t pl_a;/* array_pos */
/* USB_POINTERS_ARRAY_SIZE - array_pos */
/* MAX_FRAMELEN - */
/* USB_BUFSIZE - */
static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
int8_t memok = 1;
/* , */
if( pl_a !=0 && p_a !=0){
int32_t mem_lag = array_pos[(p_a - 1) % USB_POINTERS_ARRAY_SIZE] - array_pos[(pl_a - 1) % USB_POINTERS_ARRAY_SIZE];
if(mem_lag > USB_BUFSIZE - MAX_FRAMELEN)
memok = 0;
}
/* ,
(array_pos) */
if(*Len < USB_BUFSIZE && *Len != 0 && memok){
uint16_t offset = pos_int % USB_BUFSIZE;
uint16_t new_pos = offset + *Len;
uint8_t split = 0;
if (new_pos > USB_BUFSIZE){
split = 1;
}
if(split){
int len1 = USB_BUFSIZE - offset;
int len2 = *Len - len1;
memcpy(usb_buf + offset, Buf, len1);
memcpy(usb_buf, Buf + len1, len2);
}
else
memcpy(usb_buf + offset, Buf, *Len);
pos_int += *Len;
array_pos[p_a % USB_POINTERS_ARRAY_SIZE] = pos_int;
p_a++;
}
USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
USBD_CDC_ReceivePacket(&hUsbDeviceFS);
return (USBD_OK);
}
(main.c) ENC28J60:
if(pl_a < p_a){
uint32_t prev = 0;
if(pl_a > 0)
prev = array_pos[(pl_a - 1) % USB_POINTERS_ARRAY_SIZE];
/* ( ), CDC_Receive_FS */
int32_t n = array_pos[pl_a % USB_POINTERS_ARRAY_SIZE] - prev;//usb frame size
/* */
uint8_t *from = usb_buf + prev % USB_BUFSIZE;
/* */
uint8_t right_n = 1;
if (n < 0 || n > MAX_FRAMELEN){
right_n = 0;
}
/* . 6 ( 4 2 ) */
if((packet_len == 0) && packet_start && (n > 5) && right_n){
/* . */
uint32_t sign = read32(from,usb_buf);
/* 4 */
uint8_t *next = next_usb_ptr(from,usb_buf,4);
/* */
packet_size = read16(next,usb_buf);// 2 bytes after sign is packet length
/* */
if (packet_size > MAX_FRAMELEN || sign != PACKET_START_SIGN){
packet_size = 0;
}
else{
/* */
next = next_usb_ptr(from,usb_buf,6);
copy_buf(packet_buf, next, usb_buf, n - 6);
packet_len = n - 6;
packet_next_ptr = packet_buf + packet_len;
packet_start = 0;
}
}
/* */
else if(packet_len < packet_size && right_n){
/* */
copy_buf(packet_next_ptr, from, usb_buf, n);
packet_len += n;
packet_next_ptr = packet_buf + packet_len;
}
/* */
else if (packet_len > packet_size){
packet_len = 0;
packet_start = 1;
}
/* enc28j60 */
if(packet_len == packet_size && packet_size > 0){
enc28j60_packetSend(packet_buf, packet_size);
packet_len = 0;
packet_start = 1;
}
pl_a++;
}
ENC28J60 USB :
len = enc28j60_packetReceive(net_buf,sizeof(net_buf));
if (len > 0) {
*((uint16_t*)(sign_buf + 4)) = len;
while(CDC_Transmit_FS(sign_buf, sizeof(sign_buf)) == USBD_BUSY_CDC_TRANSMIT);
while(CDC_Transmit_FS(net_buf, len) == USBD_BUSY_CDC_TRANSMIT);
HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
}
CDC_Transmit_FS
, while. CDC_Transmit_FS
USBD_BUSY_CDC_TRANSMIT
USBD_BUSY
. :
if (hcdc->TxState != 0){
return USBD_BUSY_CDC_TRANSMIT;
}
ENC28J60 enc28j60_ini
, (promiscuous mode):
enc28j60_writeRegByte(ERXFCON,0);
Raspberry
eth0 ip . ping
sudo ifconfig eth0 up 10.0.0.2/24 ping 10.0.0.2
tcpdump:
sudo tcpdump -i eth0
STM32 , ENC28J60 raspberry. STM32 , arp / icmp ( ping). , /dev/ttyACM0:
ls /dev/ttyACM*
tap_handler:
gcc tap_handler.c -o tap_handler ./tap_handler
tap_handler - raspberry, tap0, , STM32, raspberry , .
.
raspberry ssh wi-fi , , default gateway. , raspberry :
sudo route del default gateway 192.168.1.1 sudo route add default gateway 10.0.0.2
DNS ( /etc/resolv.conf nameserver, , 8.8.8.8).
Raspberry
eth0 wlan0 NAT:
echo 1 | sudo tee -a /proc/sys/net/ipv4/ip_forward
sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE
. , ( 0.5 /).
Anda tidak perlu repot dengan raspberry, tetapi langsung hubungkan kabel jaringan dari router ke ENC28J60 (Anda perlu mematikan wi-fi di komputer Anda dan mengatur alamat tap0 yang benar). Tetapi pengujian lebih mudah dengan raspberry, Anda dapat melihat semua yang terjadi di tcpdump.
Mengapa semua ini
Menggunakan bundel seperti itu dalam hidup mungkin tidak terlalu nyaman (terutama jika ada adaptor ethernet usb murah yang dijual), tetapi sangat menarik untuk membuatnya. Terima kasih atas perhatiannya. Tautan kode (proyek di Atollic TrueStudio).