diff options
Diffstat (limited to 'drivers/net/lguest_net.c')
| -rw-r--r-- | drivers/net/lguest_net.c | 550 |
1 files changed, 0 insertions, 550 deletions
diff --git a/drivers/net/lguest_net.c b/drivers/net/lguest_net.c deleted file mode 100644 index e255476..0000000 --- a/drivers/net/lguest_net.c +++ /dev/null @@ -1,550 +0,0 @@ -/*D:500 - * The Guest network driver. - * - * This is very simple a virtual network driver, and our last Guest driver. - * The only trick is that it can talk directly to multiple other recipients - * (ie. other Guests on the same network). It can also be used with only the - * Host on the network. - :*/ - -/* 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 - -/*M:011 Network code master Jeff Garzik points out numerous shortcomings in - * this driver if it aspires to greatness. - * - * Firstly, it doesn't use "NAPI": the networking's New API, and is poorer for - * it. As he says "NAPI means system-wide load leveling, across multiple - * network interfaces. Lack of NAPI can mean competition at higher loads." - * - * He also points out that we don't implement set_mac_address, so users cannot - * change the devices hardware address. When I asked why one would want to: - * "Bonding, and situations where you /do/ want the MAC address to "leak" out - * of the host onto the wider net." - * - * Finally, he would like module unloading: "It is not unrealistic to think of - * [un|re|]loading the net support module in an lguest guest. And, adding - * module support makes the programmer more responsible, because they now have - * to learn to clean up after themselves. Any driver that cannot clean up - * after itself is an incomplete driver in my book." - :*/ - -/*D:530 The "struct lguestnet_info" contains all the information we need to - * know about the network device. */ -struct lguestnet_info -{ - /* The mapped device page(s) (an array of "struct lguest_net"). */ - struct lguest_net *peer; - /* The physical address of the device page(s) */ - unsigned long peer_phys; - /* The size of the device page(s). */ - unsigned long mapsize; - - /* The lguest_device I come from */ - struct lguest_device *lgdev; - - /* My peerid (ie. my slot in the array). */ - unsigned int me; - - /* Receive queue: the network packets waiting to be filled. */ - 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); -} - -/*D:570 Each peer (ie. Guest or Host) on the network binds their receive - * buffers to a different key: we simply use the physical address of the - * device's memory page plus the peer number. The Host insists that all keys - * be a multiple of 4, so we multiply the peer number by 4. */ -static unsigned long peer_key(struct lguestnet_info *info, unsigned peernum) -{ - return info->peer_phys + 4 * peernum; -} - -/* This is the routine which sets up a "struct lguest_dma" to point to a - * network packet, similar to req_to_dma() in lguest_blk.c. The structure of a - * "struct sk_buff" has grown complex over the years: it consists of a "head" - * linear section pointed to by "skb->data", and possibly an array of - * "fragments" in the case of a non-linear packet. - * - * Our receive buffers don't use fragments at all but outgoing skbs might, so - * we handle it. */ -static void skb_to_dma(const struct sk_buff *skb, unsigned int headlen, - struct lguest_dma *dma) -{ - unsigned int i, seg; - - /* First, we put the linear region into the "struct lguest_dma". Each - * entry can't go over a page boundary, so even though all our packets - * are 1514 bytes or less, we might need to use two entries here: */ - 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)); - } - - /* Now we handle the fragments: at least they're guaranteed not to go - * over a page. skb_shinfo(skb) returns a pointer to the structure - * which tells us about the number of fragments and the fragment - * array. */ - 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) { - /* We will end up sending a truncated packet should - * this ever happen. Plus, a cool log message! */ - printk("Woah dude! Megapacket!\n"); - break; - } - dma->addr[seg] = page_to_phys(f->page) + f->page_offset; - dma->len[seg] = f->size; - } - - /* If after all that we didn't use the entire "struct lguest_dma" - * array, we terminate it with a 0 length. */ - if (seg < LGUEST_MAX_DMA_SECTIONS) - dma->len[seg] = 0; -} - -/* - * Packet transmission. - * - * Our packet transmission is a little unusual. A real network card would just - * send out the packet and leave the receivers to decide if they're interested. - * Instead, we look through the network device memory page and see if any of - * the ethernet addresses match the packet destination, and if so we send it to - * that Guest. - * - * This is made a little more complicated in two cases. The first case is - * broadcast packets: for that we send the packet to all Guests on the network, - * one at a time. The second case is "promiscuous" mode, where a Guest wants - * to see all the packets on the network. We need a way for the Guest to tell - * us it wants to see all packets, so it sets the "multicast" bit on its - * published MAC address, which is never valid in a real ethernet address. - */ -#define PROMISC_BIT 0x01 - -/* This is the callback which is summoned whenever the network device's - * multicast or promiscuous state changes. If the card is in promiscuous mode, - * we advertise that in our ethernet address in the device's memory. We do the - * same if Linux wants any or all multicast traffic. */ -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; -} - -/* A simple test function to see if a peer wants to see all packets.*/ -static int promisc(struct lguestnet_info *info, unsigned int peer) -{ - return info->peer[peer].mac[0] & PROMISC_BIT; -} - -/* Another simple function to see if a peer's advertised ethernet address - * matches a packet's destination ethernet address. */ -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; -} - -/* This is the function which actually sends a packet once we've decided a - * peer wants it: */ -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; - - /* We use our handy "struct lguest_dma" packing function to prepare - * the skb for sending. */ - skb_to_dma(skb, skb_headlen(skb), &dma); - pr_debug("xfer length %04x (%u)\n", htons(skb->len), skb->len); - - /* This is the actual send call which copies the packet. */ - lguest_send_dma(peer_key(info, peernum), &dma); - - /* Check that the entire packet was transmitted. If not, it could mean - * that the other Guest registered a short receive buffer, but this - * driver should never do that. More likely, the peer is dead. */ - 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 { - /* On success we update the stats. */ - dev->stats.tx_bytes += skb->len; - dev->stats.tx_packets++; - } -} - -/* Another helper function to tell is if a slot in the device memory is unused. - * Since we always set the Local Assignment bit in the ethernet address, the - * first byte can never be 0. */ -static int unused_peer(const struct lguest_net peer[], unsigned int num) -{ - return peer[num].mac[0] == 0; -} - -/* Finally, here is the routine which handles an outgoing packet. It's called - * "start_xmit" for traditional reasons. */ -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); - /* Extract the destination ethernet address from the packet. */ - const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; - DECLARE_MAC_BUF(mac); - - pr_debug("%s: xmit %s\n", dev->name, print_mac(mac, dest)); - - /* If it's a multicast packet, we broadcast to everyone. That's not - * very efficient, but there are very few applications which actually - * use multicast, which is a shame really. - * - * As etherdevice.h points out: "By definition the broadcast address is - * also a multicast address." So we don't have to test for broadcast - * packets separately. */ - broadcast = is_multicast_ether_addr(dest); - - /* Look through all the published ethernet addresses to see if we - * should send this packet. */ - for (i = 0; i < info->mapsize/sizeof(struct lguest_net); i++) { - /* We don't send to ourselves (we actually can't SEND_DMA to - * ourselves anyway), and don't send to unused slots.*/ - if (i == info->me || unused_peer(info->peer, i)) - continue; - - /* If it's broadcast we send it. If they want every packet we - * send it. If the destination matches their address we send - * it. Otherwise we go to the next peer. */ - 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); - /* Our routine which actually does the transfer. */ - transfer_packet(dev, skb, i); - } - - /* An xmit routine is expected to dispose of the packet, so we do. */ - dev_kfree_skb(skb); - - /* As per kernel convention, 0 means success. This is why I love - * networking: even if we never sent to anyone, that's still - * success! */ - return 0; -} - -/*D:560 - * Packet receiving. - * - * First, here's a helper routine which fills one of our array of receive - * buffers: */ -static int fill_slot(struct net_device *dev, unsigned int slot) -{ - struct lguestnet_info *info = netdev_priv(dev); - - /* We can receive ETH_DATA_LEN (1500) byte packets, plus a standard - * ethernet header of ETH_HLEN (14) bytes. */ - 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() is a helper which sets up the "struct lguest_dma" to - * point to the data in the skb: we also use it for sending out a - * packet. */ - skb_to_dma(info->skb[slot], ETH_HLEN + ETH_DATA_LEN, &info->dma[slot]); - - /* This is a Write Memory Barrier: it ensures that the entry in the - * receive buffer array is written *before* we set the "used_len" entry - * to 0. If the Host were looking at the receive buffer array from a - * different CPU, it could potentially see "used_len = 0" and not see - * the updated receive buffer information. This would be a horribly - * nasty bug, so make sure the compiler and CPU know this has to happen - * first. */ - wmb(); - /* Writing 0 to "used_len" tells the Host it can use this receive - * buffer now. */ - info->dma[slot].used_len = 0; - return 0; -} - -/* This is the actual receive routine. When we receive an interrupt from the - * Host to tell us a packet has been delivered, we arrive here: */ -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; - - /* Look through our entire receive array for an entry which has data - * in it. */ - 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; - - /* We've found one! Remember the skb (we grabbed the length - * above), and immediately refill the slot we've taken it - * from. */ - done++; - skb = info->skb[i]; - fill_slot(dev, i); - - /* This shouldn't happen: micropackets could be sent by a - * badly-behaved Guest on the network, but the Host will never - * stuff more data in the buffer than the buffer length. */ - 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(), what a great function! I've ranted about this - * function before (http://lkml.org/lkml/1999/9/26/24). You - * call it after you've added data to the end of an skb (in - * this case, it was the Host which wrote the data). */ - skb_put(skb, length); - - /* The ethernet header contains a protocol field: we use the - * standard helper to extract it, and place the result in - * skb->protocol. The helper also sets up skb->pkt_type and - * eats up the ethernet header from the front of the packet. */ - skb->protocol = eth_type_trans(skb, dev); - - /* If this device doesn't need checksums for sending, we also - * don't need to check the packets when they come in. */ - if (dev->features & NETIF_F_NO_CSUM) - skb->ip_summed = CHECKSUM_UNNECESSARY; - - /* As a last resort for debugging the driver or the lguest I/O - * subsystem, you can uncomment the "#define DEBUG" at the top - * of this file, which turns all the pr_debug() into printk() - * and floods the logs. */ - pr_debug("Receiving skb proto 0x%04x len %i type %i\n", - ntohs(skb->protocol), skb->len, skb->pkt_type); - - /* Update the packet and byte counts (visible from ifconfig, - * and good for debugging). */ - dev->stats.rx_bytes += skb->len; - dev->stats.rx_packets++; - - /* Hand our fresh network packet into the stack's "network - * interface receive" routine. That will free the packet - * itself when it's finished. */ - netif_rx(skb); - } - - /* If we found any packets, we assume the interrupt was for us. */ - return done ? IRQ_HANDLED : IRQ_NONE; -} - -/*D:550 This is where we start: when the device is brought up by dhcpd or - * ifconfig. At this point we advertise our MAC address to the rest of the - * network, and register receive buffers ready for incoming packets. */ -static int lguestnet_open(struct net_device *dev) -{ - int i; - struct lguestnet_info *info = netdev_priv(dev); - - /* Copy our MAC address into the device page, so others on the network - * can find us. */ - memcpy(info->peer[info->me].mac, dev->dev_addr, ETH_ALEN); - - /* We might already be in promisc mode (dev->flags & IFF_PROMISC). Our - * set_multicast callback handles this already, so we call it now. */ - lguestnet_set_multicast(dev); - - /* Allocate packets and put them into our "struct lguest_dma" array. - * If we fail to allocate all the packets we could still limp along, - * but it's a sign of real stress so we should probably give up now. */ - for (i = 0; i < ARRAY_SIZE(info->dma); i++) { - if (fill_slot(dev, i) != 0) - goto cleanup; - } - - /* Finally we tell the Host where our array of "struct lguest_dma" - * receive buffers is, binding it to the key corresponding to the - * device's physical memory plus our peerid. */ - 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; -} -/*:*/ - -/* The close routine is called when the device is no longer in use: we clean up - * elegantly. */ -static int lguestnet_close(struct net_device *dev) -{ - unsigned int i; - struct lguestnet_info *info = netdev_priv(dev); - - /* Clear all trace of our existence out of the device memory by setting - * the slot which held our MAC address to 0 (unused). */ - memset(&info->peer[info->me], 0, sizeof(info->peer[info->me])); - - /* Unregister our array of receive buffers */ - 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; -} - -/*D:510 The network device probe function is basically a standard ethernet - * device setup. It reads the "struct lguest_device_desc" and sets the "struct - * net_device". Oh, the line-by-line excitement! Let's skip over it. :*/ -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; - - /* Ethernet defaults with some changes */ - ether_setup(dev); - dev->set_mac_address = NULL; - random_ether_addr(dev->dev_addr); - - dev->open = lguestnet_open; - dev->stop = lguestnet_close; - dev->hard_start_xmit = lguestnet_start_xmit; - - /* We don't actually support multicast yet, but turning on/off - * promisc also calls dev->set_multicast_list. */ - dev->set_multicast_list = lguestnet_set_multicast; - SET_NETDEV_DEV(dev, &lgdev->dev); - - /* The network code complains if you have "scatter-gather" capability - * if you don't also handle checksums (it seem that would be - * "illogical"). So we use a lie of omission and don't tell it that we - * can handle scattered packets unless we also don't want checksums, - * even though to us they're completely independent. */ - 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); - /* Finally, we put the "struct net_device" in the generic "struct - * lguest_device"s private pointer. Again, it's not necessary, but - * makes sure the cool kernel kids don't tease us. */ - 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"); - -/*D:580 - * This is the last of the Drivers, and with this we have covered the many and - * wonderous and fine (and boring) details of the Guest. - * - * "make Launcher" beckons, where we answer questions like "Where do Guests - * come from?", and "What do you do when someone asks for optimization?" - */ |
