/* A simple network driver for lguest.
*
* Copyright 2006 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
//#define DEBUG
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/module.h>
#include <linux/mm_types.h>
#include <linux/io.h>
#include <linux/lguest_bus.h>
#define SHARED_SIZE PAGE_SIZE
#define MAX_LANS 4
#define NUM_SKBS 8
struct lguestnet_info
{
/* The shared page(s). */
struct lguest_net *peer;
unsigned long peer_phys;
unsigned long mapsize;
/* The lguest_device I come from */
struct lguest_device *lgdev;
/* My peerid. */
unsigned int me;
/* Receive queue. */
struct sk_buff *skb[NUM_SKBS];
struct lguest_dma dma[NUM_SKBS];
};
/* How many bytes left in this page. */
static unsigned int rest_of_page(void *data)
{
return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE);
}
/* Simple convention: offset 4 * peernum. */
static unsigned long peer_key(struct lguestnet_info *info, unsigned peernum)
{
return info->peer_phys + 4 * peernum;
}
static void skb_to_dma(const struct sk_buff *skb, unsigned int headlen,
struct lguest_dma *dma)
{
unsigned int i, seg;
for (i = seg = 0; i < headlen; seg++, i += rest_of_page(skb->data+i)) {
dma->addr[seg] = virt_to_phys(skb->data + i);
dma->len[seg] = min((unsigned)(headlen - i),
rest_of_page(skb->data + i));
}
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++, seg++) {
const skb_frag_t *f = &skb_shinfo(skb)->frags[i];
/* Should not happen with MTU less than 64k - 2 * PAGE_SIZE. */
if (seg == LGUEST_MAX_DMA_SECTIONS) {
printk("Woah dude! Megapacket!\n");
break;
}
dma->addr[seg] = page_to_phys(f->page) + f->page_offset;
dma->len[seg] = f->size;
}
if (seg < LGUEST_MAX_DMA_SECTIONS)
dma->len[seg] = 0;
}
/* We overload multicast bit to show promiscuous mode. */
#define PROMISC_BIT 0x01
static void lguestnet_set_multicast(struct net_device *dev)
{
struct lguestnet_info *info = netdev_priv(dev);
if ((dev->flags & (IFF_PROMISC|IFF_ALLMULTI)) || dev->mc_count)
info->peer[info->me].mac[0] |= PROMISC_BIT;
else
info->peer[info->me].mac[0] &= ~PROMISC_BIT;
}
static int promisc(struct lguestnet_info *info, unsigned int peer)
{
return info->peer[peer].mac[0] & PROMISC_BIT;
}
static int mac_eq(const unsigned char mac[ETH_ALEN],
struct lguestnet_info *info, unsigned int peer)
{
/* Ignore multicast bit, which peer turns on to mean promisc. */
if ((info->peer[peer].mac[0] & (~PROMISC_BIT)) != mac[0])
return 0;
return memcmp(mac+1, info->peer[peer].mac+1, ETH_ALEN-1) == 0;
}
static void transfer_packet(struct net_device *dev,
struct sk_buff *skb,
unsigned int peernum)
{
struct lguestnet_info *info = netdev_priv(dev);
struct lguest_dma dma;
skb_to_dma(skb, skb_headlen(skb), &dma);
pr_debug("xfer length %04x (%u)\n", htons(skb->len), skb->len);
lguest_send_dma(peer_key(info, peernum), &dma);
if (dma.used_len != skb->len) {
dev->stats.tx_carrier_errors++;
pr_debug("Bad xfer to peer %i: %i of %i (dma %p/%i)\n",
peernum, dma.used_len, skb->len,
(void *)dma.addr[0], dma.len[0]);
} else {
dev->stats.tx_bytes += skb->len;
dev->stats.tx_packets++;
}
}
static int unused_peer(const struct lguest_net peer[], unsigned int num)
{
return peer[num].mac[0] == 0;
}
static int lguestnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
unsigned int i;
int broadcast;
struct lguestnet_info *info = netdev_priv(dev);
const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
pr_debug("%s: xmit %02x:%02x:%02x:%02x:%02x:%02x\n",
dev->name, dest[0],dest[1],dest[2],dest[3],dest[4],dest[5]);
broadcast = is_multicast_ether_addr(dest);
for (i = 0; i < info->mapsize/sizeof(struct lguest_net); i++) {
if (i == info->me || unused_peer(info->peer, i))
continue;
if (!broadcast && !promisc(info, i) && !mac_eq(dest, info, i))
continue;
pr_debug("lguestnet %s: sending from %i to %i\n",
dev->name, info->me, i);
transfer_packet(dev, skb, i);
}
dev_kfree_skb(skb);
return 0;
}
/* Find a new skb to put in this slot in shared mem. */
static int fill_slot(struct net_device *dev, unsigned int slot)
{
struct lguestnet_info *info = netdev_priv(dev);
/* Try to create and register a new one. */
info->skb[slot] = netdev_alloc_skb(dev, ETH_HLEN + ETH_DATA_LEN);
if (!info->skb[slot]) {
printk("%s: could not fill slot %i\n", dev->name, slot);
return -ENOMEM;
}
skb_to_dma(info->skb[slot], ETH_HLEN + ETH_DATA_LEN, &info->dma[slot]);
wmb();
/* Now we tell hypervisor it can use the slot. */
info->dma[slot].used_len = 0;
return 0;
}
static irqreturn_t lguestnet_rcv(int irq, void *dev_id)
{
struct net_device *dev = dev_id;
struct lguestnet_info *info = netdev_priv(dev);
unsigned int i, done = 0;
for (i = 0; i < ARRAY_SIZE(info->dma); i++) {
unsigned int length;
struct sk_buff *skb;
length = info->dma[i].used_len;
if (length == 0)
continue;
done++;
skb = info->skb[i];
fill_slot(dev, i);
if (length < ETH_HLEN || length > ETH_HLEN + ETH_DATA_LEN) {
pr_debug(KERN_WARNING "%s: unbelievable skb len: %i\n",
dev->name, length);
dev_kfree_skb(skb);
continue;
}
skb_put(skb, length);
skb->protocol = eth_type_trans(skb, dev);
/* This is a reliable transport. */
if (dev->features & NETIF_F_NO_CSUM)
skb->ip_summed = CHECKSUM_UNNECESSARY;
pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
ntohs(skb->protocol), skb->len, skb->pkt_type);
dev->stats.rx_bytes += skb->len;
dev->stats.rx_packets++;
netif_rx(skb);
}
return done ? IRQ_HANDLED : IRQ_NONE;
}
static int lguestnet_open(struct net_device *dev)
{
int i;
struct lguestnet_info *info = netdev_priv(dev);
/* Set up our MAC address */
memcpy(info->peer[info->me].mac, dev->dev_addr, ETH_ALEN);
/* Turn on promisc mode if needed */
lguestnet_set_multicast(dev);
for (i = 0; i < ARRAY_SIZE(info->dma); i++) {
if (fill_slot(dev, i) != 0)
goto cleanup;
}
if (lguest_bind_dma(peer_key(info,info->me), info->dma,
NUM_SKBS, lgdev_irq(info->lgdev)) != 0)
goto cleanup;
return 0;
cleanup:
while (--i >= 0)
dev_kfree_skb(info->skb[i]);
return -ENOMEM;
}
static int lguestnet_close(struct net_device *dev)
{
unsigned int i;
struct lguestnet_info *info = netdev_priv(dev);
/* Clear all trace: others might deliver packets, we'll ignore it. */
memset(&info->peer[info->me], 0, sizeof(info->peer[info->me]));
/* Deregister sg lists. */
lguest_unbind_dma(peer_key(info, info->me), info->dma);
for (i = 0; i < ARRAY_SIZE(info->dma); i++)
dev_kfree_skb(info->skb[i]);
return 0;
}
static int lguestnet_probe(struct lguest_device *lgdev)
{
int err, irqf = IRQF_SHARED;
struct net_device *dev;
struct lguestnet_info *info;
struct lguest_device_desc *desc = &lguest_devices[lgdev->index];
pr_debug("lguest_net: probing for device %i\n", lgdev->index);
dev = alloc_etherdev(sizeof(struct lguestnet_info));
if (!dev)
return -ENOMEM;
SET_MODULE_OWNER(dev);
/* Ethernet defaults with some changes */
ether_setup(dev);
dev->set_mac_address = NULL;
dev->dev_addr[0] = 0x02; /* set local assignment bit (IEEE802) */
dev->dev_addr[1] = 0x00;
memcpy(&dev->dev_addr[2], &lguest_data.guestid, 2);
dev->dev_addr[4] = 0x00;
dev->dev_addr[5] = 0x00;
dev->open = lguestnet_open;
dev->stop = lguestnet_close;
dev->hard_start_xmit = lguestnet_start_xmit;
/* Turning on/off promisc will call dev->set_multicast_list.
* We don't actually support multicast yet */
dev->set_multicast_list = lguestnet_set_multicast;
SET_NETDEV_DEV(dev, &lgdev->dev);
if (desc->features & LGUEST_NET_F_NOCSUM)
dev->features = NETIF_F_SG|NETIF_F_NO_CSUM;
info = netdev_priv(dev);
info->mapsize = PAGE_SIZE * desc->num_pages;
info->peer_phys = ((unsigned long)desc->pfn << PAGE_SHIFT);
info->lgdev = lgdev;
info->peer = lguest_map(info->peer_phys, desc->num_pages);
if (!info->peer) {
err = -ENOMEM;
goto free;
}
/* This stores our peerid (upper bits reserved for future). */
info->me = (desc->features & (info->mapsize-1));
err = register_netdev(dev);
if (err) {
pr_debug("lguestnet: registering device failed\n");
goto unmap;
}
if (lguest_devices[lgdev->index].features & LGUEST_DEVICE_F_RANDOMNESS)
irqf |= IRQF_SAMPLE_RANDOM;
if (request_irq(lgdev_irq(lgdev), lguestnet_rcv, irqf, "lguestnet",
dev) != 0) {
pr_debug("lguestnet: cannot get irq %i\n", lgdev_irq(lgdev));
goto unregister;
}
pr_debug("lguestnet: registered device %s\n", dev->name);
lgdev->private = dev;
return 0;
unregister:
unregister_netdev(dev);
unmap:
lguest_unmap(info->peer);
free:
free_netdev(dev);
return err;
}
static struct lguest_driver lguestnet_drv = {
.name = "lguestnet",
.owner = THIS_MODULE,
.device_type = LGUEST_DEVICE_T_NET,
.probe = lguestnet_probe,
};
static __init int lguestnet_init(void)
{
return register_lguest_driver(&lguestnet_drv);
}
module_init(lguestnet_init);
MODULE_DESCRIPTION("Lguest network driver");
MODULE_LICENSE("GPL");
