cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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gl620a.c (6007B)


      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * GeneSys GL620USB-A based links
      4 * Copyright (C) 2001 by Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
      5 * Copyright (C) 2001 by Stanislav Brabec <utx@penguin.cz>
      6 */
      7
      8// #define	DEBUG			// error path messages, extra info
      9// #define	VERBOSE			// more; success messages
     10
     11#include <linux/module.h>
     12#include <linux/netdevice.h>
     13#include <linux/etherdevice.h>
     14#include <linux/ethtool.h>
     15#include <linux/workqueue.h>
     16#include <linux/mii.h>
     17#include <linux/usb.h>
     18#include <linux/usb/usbnet.h>
     19#include <linux/gfp.h>
     20
     21
     22/*
     23 * GeneSys GL620USB-A (www.genesyslogic.com.tw)
     24 *
     25 * ... should partially interop with the Win32 driver for this hardware.
     26 * The GeneSys docs imply there's some NDIS issue motivating this framing.
     27 *
     28 * Some info from GeneSys:
     29 *  - GL620USB-A is full duplex; GL620USB is only half duplex for bulk.
     30 *    (Some cables, like the BAFO-100c, use the half duplex version.)
     31 *  - For the full duplex model, the low bit of the version code says
     32 *    which side is which ("left/right").
     33 *  - For the half duplex type, a control/interrupt handshake settles
     34 *    the transfer direction.  (That's disabled here, partially coded.)
     35 *    A control URB would block until other side writes an interrupt.
     36 *
     37 * Original code from Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
     38 * and merged into "usbnet" by Stanislav Brabec <utx@penguin.cz>.
     39 */
     40
     41// control msg write command
     42#define GENELINK_CONNECT_WRITE			0xF0
     43// interrupt pipe index
     44#define GENELINK_INTERRUPT_PIPE			0x03
     45// interrupt read buffer size
     46#define INTERRUPT_BUFSIZE			0x08
     47// interrupt pipe interval value
     48#define GENELINK_INTERRUPT_INTERVAL		0x10
     49// max transmit packet number per transmit
     50#define GL_MAX_TRANSMIT_PACKETS			32
     51// max packet length
     52#define GL_MAX_PACKET_LEN			1514
     53// max receive buffer size
     54#define GL_RCV_BUF_SIZE		\
     55	(((GL_MAX_PACKET_LEN + 4) * GL_MAX_TRANSMIT_PACKETS) + 4)
     56
     57struct gl_packet {
     58	__le32		packet_length;
     59	char		packet_data[];
     60};
     61
     62struct gl_header {
     63	__le32			packet_count;
     64	struct gl_packet	packets;
     65};
     66
     67static int genelink_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
     68{
     69	struct gl_header	*header;
     70	struct gl_packet	*packet;
     71	struct sk_buff		*gl_skb;
     72	u32			size;
     73	u32			count;
     74
     75	/* This check is no longer done by usbnet */
     76	if (skb->len < dev->net->hard_header_len)
     77		return 0;
     78
     79	header = (struct gl_header *) skb->data;
     80
     81	// get the packet count of the received skb
     82	count = le32_to_cpu(header->packet_count);
     83	if (count > GL_MAX_TRANSMIT_PACKETS) {
     84		netdev_dbg(dev->net,
     85			   "genelink: invalid received packet count %u\n",
     86			   count);
     87		return 0;
     88	}
     89
     90	// set the current packet pointer to the first packet
     91	packet = &header->packets;
     92
     93	// decrement the length for the packet count size 4 bytes
     94	skb_pull(skb, 4);
     95
     96	while (count > 1) {
     97		// get the packet length
     98		size = le32_to_cpu(packet->packet_length);
     99
    100		// this may be a broken packet
    101		if (size > GL_MAX_PACKET_LEN) {
    102			netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
    103				   size);
    104			return 0;
    105		}
    106
    107		// allocate the skb for the individual packet
    108		gl_skb = alloc_skb(size, GFP_ATOMIC);
    109		if (gl_skb) {
    110
    111			// copy the packet data to the new skb
    112			skb_put_data(gl_skb, packet->packet_data, size);
    113			usbnet_skb_return(dev, gl_skb);
    114		}
    115
    116		// advance to the next packet
    117		packet = (struct gl_packet *)&packet->packet_data[size];
    118		count--;
    119
    120		// shift the data pointer to the next gl_packet
    121		skb_pull(skb, size + 4);
    122	}
    123
    124	// skip the packet length field 4 bytes
    125	skb_pull(skb, 4);
    126
    127	if (skb->len > GL_MAX_PACKET_LEN) {
    128		netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
    129			   skb->len);
    130		return 0;
    131	}
    132	return 1;
    133}
    134
    135static struct sk_buff *
    136genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
    137{
    138	int 	padlen;
    139	int	length = skb->len;
    140	int	headroom = skb_headroom(skb);
    141	int	tailroom = skb_tailroom(skb);
    142	__le32	*packet_count;
    143	__le32	*packet_len;
    144
    145	// FIXME:  magic numbers, bleech
    146	padlen = ((skb->len + (4 + 4*1)) % 64) ? 0 : 1;
    147
    148	if ((!skb_cloned(skb))
    149			&& ((headroom + tailroom) >= (padlen + (4 + 4*1)))) {
    150		if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
    151			skb->data = memmove(skb->head + (4 + 4*1),
    152					     skb->data, skb->len);
    153			skb_set_tail_pointer(skb, skb->len);
    154		}
    155	} else {
    156		struct sk_buff	*skb2;
    157		skb2 = skb_copy_expand(skb, (4 + 4*1) , padlen, flags);
    158		dev_kfree_skb_any(skb);
    159		skb = skb2;
    160		if (!skb)
    161			return NULL;
    162	}
    163
    164	// attach the packet count to the header
    165	packet_count = skb_push(skb, (4 + 4 * 1));
    166	packet_len = packet_count + 1;
    167
    168	*packet_count = cpu_to_le32(1);
    169	*packet_len = cpu_to_le32(length);
    170
    171	// add padding byte
    172	if ((skb->len % dev->maxpacket) == 0)
    173		skb_put(skb, 1);
    174
    175	return skb;
    176}
    177
    178static int genelink_bind(struct usbnet *dev, struct usb_interface *intf)
    179{
    180	dev->hard_mtu = GL_RCV_BUF_SIZE;
    181	dev->net->hard_header_len += 4;
    182	dev->in = usb_rcvbulkpipe(dev->udev, dev->driver_info->in);
    183	dev->out = usb_sndbulkpipe(dev->udev, dev->driver_info->out);
    184	return 0;
    185}
    186
    187static const struct driver_info	genelink_info = {
    188	.description =	"Genesys GeneLink",
    189	.flags =	FLAG_POINTTOPOINT | FLAG_FRAMING_GL | FLAG_NO_SETINT,
    190	.bind =		genelink_bind,
    191	.rx_fixup =	genelink_rx_fixup,
    192	.tx_fixup =	genelink_tx_fixup,
    193
    194	.in = 1, .out = 2,
    195
    196#ifdef	GENELINK_ACK
    197	.check_connect =genelink_check_connect,
    198#endif
    199};
    200
    201static const struct usb_device_id	products [] = {
    202
    203{
    204	USB_DEVICE(0x05e3, 0x0502),	// GL620USB-A
    205	.driver_info =	(unsigned long) &genelink_info,
    206},
    207	/* NOT: USB_DEVICE(0x05e3, 0x0501),	// GL620USB
    208	 * that's half duplex, not currently supported
    209	 */
    210	{ },		// END
    211};
    212MODULE_DEVICE_TABLE(usb, products);
    213
    214static struct usb_driver gl620a_driver = {
    215	.name =		"gl620a",
    216	.id_table =	products,
    217	.probe =	usbnet_probe,
    218	.disconnect =	usbnet_disconnect,
    219	.suspend =	usbnet_suspend,
    220	.resume =	usbnet_resume,
    221	.disable_hub_initiated_lpm = 1,
    222};
    223
    224module_usb_driver(gl620a_driver);
    225
    226MODULE_AUTHOR("Jiun-Jie Huang");
    227MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
    228MODULE_LICENSE("GPL");
    229