lguest: the net driver

Lguest net driver

A simple net driver for lguest.

[akpm@linux-foundation.org: include fix]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Cc: Jeff Garzik <jeff@garzik.org>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 354 insertions, 0 deletions

diff --git a/drivers/net/lguest_net.c b/drivers/net/lguest_net.c
new file mode 100644
index 000000000000..112778652f7d
--- /dev/null
+++ b/drivers/net/lguest_net.c
@@ -0,0 +1,354 @@
+/* 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");