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在http://www.cs.fsu.edu/找的snull.c想做一个虚拟网卡。然后做成内核模块的方式。内核版本是2.6.27.5
这个是源码:
snull.c
- #include <linux/module.h>
- #include <linux/init.h>
- #include <linux/moduleparam.h>
- #include <linux/sched.h>
- #include <linux/kernel.h> /* printk() */
- #include <linux/slab.h> /* kmalloc() */
- #include <linux/errno.h> /* error codes */
- #include <linux/types.h> /* size_t */
- #include <linux/interrupt.h> /* mark_bh */
- #include <linux/in.h>
- #include <linux/netdevice.h> /* struct device, and other headers */
- #include <linux/etherdevice.h> /* eth_type_trans */
- #include <linux/ip.h> /* struct iphdr */
- #include <linux/tcp.h> /* struct tcphdr */
- #include <linux/skbuff.h>
- #include "snull.h"
- #include <linux/in6.h>
- #include <asm/checksum.h>
- MODULE_AUTHOR("Alessandro Rubini, Jonathan Corbet");
- MODULE_LICENSE("Dual BSD/GPL");
- static int lockup = 0;
- module_param(lockup, int, 0);
- //static int timeout = SNULL_TIMEOUT;
- static int timeout = 10;
- module_param(timeout, int, 0);
- static int use_napi = 0;
- module_param(use_napi, int, 0);
- struct net_device *snull_devs[2];
- struct snull_packet {
- struct snull_packet *next;
- struct net_device *dev;
- int datalen;
- u8 data[ETH_DATA_LEN];
- };
- int pool_size = 8;
- module_param(pool_size, int, 0);
- struct snull_priv {
- struct net_device_stats stats;
- int status;
- struct snull_packet *ppool;
- struct snull_packet *rx_queue; /* List of incoming packets */
- int rx_int_enabled;
- int tx_packetlen;
- u8 *tx_packetdata;
- struct sk_buff *skb;
- spinlock_t lock;
- struct net_device *dev;
- struct napi_struct napi;
- };
- static void snull_tx_timeout(struct net_device *dev);
- static void (*snull_interrupt)(int, void *, struct pt_regs *);
- void snull_setup_pool(struct net_device *dev)
- {
- struct snull_priv *priv = netdev_priv(dev);
- int i;
- struct snull_packet *pkt;
- priv->ppool = NULL;
- for (i = 0; i < pool_size; i++) {
- pkt = kmalloc (sizeof (struct snull_packet), GFP_KERNEL);
- if (pkt == NULL) {
- printk (KERN_NOTICE "Ran out of memory allocating packet pool\n");
- return;
- }
- pkt->dev = dev;
- pkt->next = priv->ppool;
- priv->ppool = pkt;
- }
- }
- void snull_teardown_pool(struct net_device *dev)
- {
- struct snull_priv *priv = netdev_priv(dev);
- struct snull_packet *pkt;
-
- while ((pkt = priv->ppool)) {
- priv->ppool = pkt->next;
- kfree (pkt);
- /* FIXME - in-flight packets ? */
- }
- }
- struct snull_packet *snull_get_tx_buffer(struct net_device *dev)
- {
- struct snull_priv *priv = netdev_priv(dev);
- unsigned long flags;
- struct snull_packet *pkt;
-
- spin_lock_irqsave(&priv->lock, flags);
- pkt = priv->ppool;
- priv->ppool = pkt->next;
- if (priv->ppool == NULL) {
- printk (KERN_INFO "Pool empty\n");
- netif_stop_queue(dev);
- }
- spin_unlock_irqrestore(&priv->lock, flags);
- return pkt;
- }
- void snull_release_buffer(struct snull_packet *pkt)
- {
- unsigned long flags;
- struct snull_priv *priv = netdev_priv(pkt->dev);
-
- spin_lock_irqsave(&priv->lock, flags);
- pkt->next = priv->ppool;
- priv->ppool = pkt;
- spin_unlock_irqrestore(&priv->lock, flags);
- if (netif_queue_stopped(pkt->dev) && pkt->next == NULL)
- netif_wake_queue(pkt->dev);
- }
- void snull_enqueue_buf(struct net_device *dev, struct snull_packet *pkt)
- {
- unsigned long flags;
- struct snull_priv *priv = netdev_priv(dev);
- spin_lock_irqsave(&priv->lock, flags);
- pkt->next = priv->rx_queue; /* FIXME - misorders packets */
- priv->rx_queue = pkt;
- spin_unlock_irqrestore(&priv->lock, flags);
- }
- struct snull_packet *snull_dequeue_buf(struct net_device *dev)
- {
- struct snull_priv *priv = netdev_priv(dev);
- struct snull_packet *pkt;
- unsigned long flags;
- spin_lock_irqsave(&priv->lock, flags);
- pkt = priv->rx_queue;
- if (pkt != NULL)
- priv->rx_queue = pkt->next;
- spin_unlock_irqrestore(&priv->lock, flags);
- return pkt;
- }
- static void snull_rx_ints(struct net_device *dev, int enable)
- {
- struct snull_priv *priv = netdev_priv(dev);
- priv->rx_int_enabled = enable;
- }
- int snull_open(struct net_device *dev)
- {
- memcpy(dev->dev_addr, "\0SNUL0", ETH_ALEN);
- if (dev == snull_devs[1])
- dev->dev_addr[ETH_ALEN-1]++; /* \0SNUL1 */
- netif_start_queue(dev);
- return 0;
- }
- int snull_release(struct net_device *dev)
- {
- /* release ports, irq and such -- like fops->close */
- netif_stop_queue(dev); /* can't transmit any more */
- return 0;
- }
- int snull_set_mac_address(struct net_device *dev,void *p)
- {
- int i;
- struct sockaddr *addr = p;
- if(netif_running(dev))
- {
- return -EBUSY;
- }
-
- if(!is_valid_ether_addr(addr->sa_data))
- {
- return -EADDRNOTAVAIL;
- }
-
- memcpy(dev->dev_addr,addr->sa_data,dev->addr_len);
-
- memcpy(dev->dev_addr, "\0SNUL0", ETH_ALEN);
- printk(KERN_ALERT "mac_open2,%s\n",dev->dev_addr);
- if (dev == snull_devs[1])
- dev->dev_addr[ETH_ALEN-1]++; /* \0SNUL1 */
- return 0;
- }
- int snull_config(struct net_device *dev, struct ifmap *map)
- {
- printk(KERN_ALERT "snull_config\n");
- if (dev->flags & IFF_UP) /* can't act on a running interface */
- return -EBUSY;
- /* Don't allow changing the I/O address */
- if (map->base_addr != dev->base_addr) {
- printk(KERN_WARNING "snull: Can't change I/O address\n");
- return -EOPNOTSUPP;
- }
- /* Allow changing the IRQ */
- if (map->irq != dev->irq) {
- dev->irq = map->irq;
- /* request_irq() is delayed to open-time */
- }
- /* ignore other fields */
- return 0;
- }
- void snull_rx(struct net_device *dev, struct snull_packet *pkt)
- {
- struct sk_buff *skb;
- struct snull_priv *priv = netdev_priv(dev);
- skb = dev_alloc_skb(pkt->datalen + 2);
- if (!skb) {
- if (printk_ratelimit())
- printk(KERN_NOTICE "snull rx: low on mem - packet dropped\n");
- priv->stats.rx_dropped++;
- goto out;
- }
- skb_reserve(skb, 2); /* align IP on 16B boundary */
- memcpy(skb_put(skb, pkt->datalen), pkt->data, pkt->datalen);
- /* Write metadata, and then pass to the receive level */
- skb->dev = dev;
- skb->protocol = eth_type_trans(skb, dev);
- skb->ip_summed = CHECKSUM_UNNECESSARY; /* don't check it */
- priv->stats.rx_packets++;
- priv->stats.rx_bytes += pkt->datalen;
- netif_rx(skb);
- out:
- return;
- }
-
- /*
- * The poll implementation.
- */
- static int snull_poll(struct napi_struct *napi, int budget)
- {
- int npackets = 0;
- struct sk_buff *skb;
- struct snull_priv *priv = container_of(napi, struct snull_priv, napi);
- struct net_device *dev = priv->dev;
- struct snull_packet *pkt;
-
- while (npackets < budget && priv->rx_queue) {
- pkt = snull_dequeue_buf(dev);
- skb = dev_alloc_skb(pkt->datalen + 2);
- if (! skb) {
- if (printk_ratelimit())
- printk(KERN_NOTICE "snull: packet dropped\n");
- priv->stats.rx_dropped++;
- snull_release_buffer(pkt);
- continue;
- }
- skb_reserve(skb, 2); /* align IP on 16B boundary */
- memcpy(skb_put(skb, pkt->datalen), pkt->data, pkt->datalen);
- skb->dev = dev;
- skb->protocol = eth_type_trans(skb, dev);
- skb->ip_summed = CHECKSUM_UNNECESSARY; /* don't check it */
- netif_receive_skb(skb);
- /* Maintain stats */
- npackets++;
- priv->stats.rx_packets++;
- priv->stats.rx_bytes += pkt->datalen;
- snull_release_buffer(pkt);
- }
- if (npackets < budget) {
- napi_complete(napi);
- snull_rx_ints(dev, 1);
- }
- return npackets;
- }
-
-
- static void snull_regular_interrupt(int irq, void *dev_id, struct pt_regs *regs)
- {
- int statusword;
- struct snull_priv *priv;
- struct snull_packet *pkt = NULL;
- struct net_device *dev = (struct net_device *)dev_id;
- /* ... and check with hw if it's really ours */
- /* paranoid */
- if (!dev)
- return;
- /* Lock the device */
- priv = netdev_priv(dev);
- spin_lock(&priv->lock);
- statusword = priv->status;
- priv->status = 0;
- if (statusword & SNULL_RX_INTR) {
- /* send it to snull_rx for handling */
- pkt = priv->rx_queue;
- if (pkt) {
- priv->rx_queue = pkt->next;
- snull_rx(dev, pkt);
- }
- }
- if (statusword & SNULL_TX_INTR) {
- /* a transmission is over: free the skb */
- priv->stats.tx_packets++;
- priv->stats.tx_bytes += priv->tx_packetlen;
- dev_kfree_skb(priv->skb);
- }
- /* Unlock the device and we are done */
- spin_unlock(&priv->lock);
- if (pkt) snull_release_buffer(pkt); /* Do this outside the lock! */
- return;
- }
- static void snull_napi_interrupt(int irq, void *dev_id, struct pt_regs *regs)
- {
- int statusword;
- struct snull_priv *priv;
- struct net_device *dev = (struct net_device *)dev_id;
- if (!dev)
- return;
- /* Lock the device */
- priv = netdev_priv(dev);
- spin_lock(&priv->lock);
- statusword = priv->status;
- priv->status = 0;
- if (statusword & SNULL_RX_INTR) {
- snull_rx_ints(dev, 0); /* Disable further interrupts */
- napi_schedule(&priv->napi);
- }
- if (statusword & SNULL_TX_INTR) {
- priv->stats.tx_packets++;
- priv->stats.tx_bytes += priv->tx_packetlen;
- dev_kfree_skb(priv->skb);
- }
- spin_unlock(&priv->lock);
- return;
- }
- static void snull_hw_tx(char *buf, int len, struct net_device *dev)
- {
- struct iphdr *ih;
- struct net_device *dest;
- struct snull_priv *priv;
- u32 *saddr, *daddr;
- struct snull_packet *tx_buffer;
-
- /* I am paranoid. Ain't I? */
- if (len < sizeof(struct ethhdr) + sizeof(struct iphdr)) {
- printk("snull: Hmm... packet too short (%i octets)\n",
- len);
- return;
- }
- if (0) { /* enable this conditional to look at the data */
- int i;
- PDEBUG("len is %i\n" KERN_DEBUG "data:",len);
- for (i=14 ; i<len; i++)
- printk(" %02x",buf[i]&0xff);
- printk("\n");
- }
- ih = (struct iphdr *)(buf+sizeof(struct ethhdr));
- saddr = &ih->saddr;
- daddr = &ih->daddr;
- ((u8 *)saddr)[2] ^= 1; /* change the third octet (class C) */
- ((u8 *)daddr)[2] ^= 1;
- ih->check = 0; /* and rebuild the checksum (ip needs it) */
- ih->check = ip_fast_csum((unsigned char *)ih,ih->ihl);
- if (dev == snull_devs[0])
- PDEBUGG("%08x:%05i --> %08x:%05i\n",
- ntohl(ih->saddr),ntohs(((struct tcphdr *)(ih+1))->source),
- ntohl(ih->daddr),ntohs(((struct tcphdr *)(ih+1))->dest));
- else
- PDEBUGG("%08x:%05i <-- %08x:%05i\n",
- ntohl(ih->daddr),ntohs(((struct tcphdr *)(ih+1))->dest),
- ntohl(ih->saddr),ntohs(((struct tcphdr *)(ih+1))->source));
- dest = snull_devs[dev == snull_devs[0] ? 1 : 0];
- priv = netdev_priv(dest);
- tx_buffer = snull_get_tx_buffer(dev);
- tx_buffer->datalen = len;
- memcpy(tx_buffer->data, buf, len);
- snull_enqueue_buf(dest, tx_buffer);
- if (priv->rx_int_enabled) {
- priv->status |= SNULL_RX_INTR;
- snull_interrupt(0, dest, NULL);
- }
- priv = netdev_priv(dev);
- priv->tx_packetlen = len;
- priv->tx_packetdata = buf;
- priv->status |= SNULL_TX_INTR;
- if (lockup && ((priv->stats.tx_packets + 1) % lockup) == 0) {
- /* Simulate a dropped transmit interrupt */
- netif_stop_queue(dev);
- PDEBUG("Simulate lockup at %ld, txp %ld\n", jiffies,
- (unsigned long) priv->stats.tx_packets);
- }
- else
- snull_interrupt(0, dev, NULL);
- }
- int snull_tx(struct sk_buff *skb, struct net_device *dev)
- {
- int len;
- char *data, shortpkt[ETH_ZLEN];
- struct snull_priv *priv = netdev_priv(dev);
-
- data = skb->data;
- len = skb->len;
- if (len < ETH_ZLEN) {
- memset(shortpkt, 0, ETH_ZLEN);
- memcpy(shortpkt, skb->data, skb->len);
- len = ETH_ZLEN;
- data = shortpkt;
- }
- dev->trans_start = jiffies; /* save the timestamp */
- priv->skb = skb;
- snull_hw_tx(data, len, dev);
- return 0; /* Our simple device can not fail */
- }
- /*
- * Deal with a transmit timeout.
- */
- void snull_tx_timeout (struct net_device *dev)
- {
- struct snull_priv *priv = netdev_priv(dev);
- PDEBUG("Transmit timeout at %ld, latency %ld\n", jiffies,
- jiffies - dev->trans_start);
- /* Simulate a transmission interrupt to get things moving */
- priv->status = SNULL_TX_INTR;
- snull_interrupt(0, dev, NULL);
- priv->stats.tx_errors++;
- netif_wake_queue(dev);
- return;
- }
- int snull_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
- {
- PDEBUG("ioctl\n");
- return 0;
- }
- struct net_device_stats *snull_stats(struct net_device *dev)
- {
- struct snull_priv *priv = netdev_priv(dev);
- return &priv->stats;
- }
- int snull_rebuild_header(struct sk_buff *skb)
- {
- struct ethhdr *eth = (struct ethhdr *) skb->data;
- struct net_device *dev = skb->dev;
-
- memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
- memcpy(eth->h_dest, dev->dev_addr, dev->addr_len);
- eth->h_dest[ETH_ALEN-1] ^= 0x01; /* dest is us xor 1 */
- return 0;
- }
- int snull_header(struct sk_buff *skb, struct net_device *dev,
- unsigned short type, const void *daddr, const void *saddr,
- unsigned int len)
- {
- struct ethhdr *eth = (struct ethhdr *)skb_push(skb,ETH_HLEN);
- eth->h_proto = htons(type);
- memcpy(eth->h_source, saddr ? saddr : dev->dev_addr, dev->addr_len);
- memcpy(eth->h_dest, daddr ? daddr : dev->dev_addr, dev->addr_len);
- eth->h_dest[ETH_ALEN-1] ^= 0x01; /* dest is us xor 1 */
- return (dev->hard_header_len);
- }
- int snull_change_mtu(struct net_device *dev, int new_mtu)
- {
- unsigned long flags;
- struct snull_priv *priv = netdev_priv(dev);
- spinlock_t *lock = &priv->lock;
-
- /* check ranges */
- if ((new_mtu < 68) || (new_mtu > 1500))
- return -EINVAL;
- spin_lock_irqsave(lock, flags);
- dev->mtu = new_mtu;
- spin_unlock_irqrestore(lock, flags);
- return 0; /* success */
- }
- static const struct header_ops snull_header_ops = {
- .create = snull_header,
- .rebuild = snull_rebuild_header,
- .cache = NULL, /* disable caching */
- };
- void snull_init(struct net_device *dev)
- {
- printk(KERN_ALERT "call snull_init\n");
- struct snull_priv *priv;
- #if 0
- #endif
- ether_setup(dev); /* assign some of the fields */
- dev->open = snull_open,
- dev->stop = snull_release,
- dev->set_config = snull_config,
- dev->hard_start_xmit = snull_tx,
- // dev->do_ioctl = snull_ioctl,
- dev->get_stats = snull_stats,
- dev->change_mtu = snull_change_mtu,
- dev->tx_timeout = snull_tx_timeout,
- dev->set_mac_address = snull_set_mac_address;
- // dev->netdev_ops = &snull_netdev_ops;
- dev->header_ops = &snull_header_ops;
- dev->watchdog_timeo = timeout;
- /* keep the default flags, just add NOARP */
- dev->flags |= IFF_NOARP;
- dev->features |= NETIF_F_NO_CSUM;
- /*
- * Then, initialize the priv field. This encloses the statistics
- * and a few private fields.
- */
- priv = netdev_priv(dev);
- memset(priv, 0, sizeof(struct snull_priv));
- priv->dev = dev;
- netif_napi_add(dev, &priv->napi, snull_poll, 2);
- /* The last parameter above is the NAPI "weight". */
- spin_lock_init(&priv->lock);
- snull_rx_ints(dev, 1); /* enable receive interrupts */
- snull_setup_pool(dev);
- }
- void snull_cleanup(void)
- {
- int i;
-
- for (i = 0; i < 2; i++) {
- if (snull_devs[i]) {
- unregister_netdev(snull_devs[i]);
- snull_teardown_pool(snull_devs[i]);
- free_netdev(snull_devs[i]);
- }
- }
- return;
- }
- int snull_init_module(void)
- {
- int result, i, ret = -ENOMEM;
- snull_interrupt = use_napi ? snull_napi_interrupt : snull_regular_interrupt;
- /* Allocate the devices */
- snull_devs[0] = alloc_netdev(sizeof(struct snull_priv), "sn%d",
- snull_init);
- snull_devs[1] = alloc_netdev(sizeof(struct snull_priv), "sn%d",
- snull_init);
- if (snull_devs[0] == NULL || snull_devs[1] == NULL)
- goto out;
- ret = -ENODEV;
- for (i = 0; i < 2; i++)
- if ((result = register_netdev(snull_devs[i])))
- printk("snull: error %i registering device \"%s\"\n",
- result, snull_devs[i]->name);
- else
- ret = 0;
- out:
- if (ret)
- snull_cleanup();
- return ret;
- }
- module_init(snull_init_module);
- module_exit(snull_cleanup);
复制代码 现在的问题是,每次在insmod snull.ko后,sn0\sn1的MAC地址都是00:00:00:00:00:00
我的理解是用ifconfig sn0 up,会调用snull_open,然后函数里面会给sn0赋值MAC地址。可是这个不行,是我的理解有问题么?
后来发现,需要ifconfig sn0 hw ether 00:12:34:56:78:90这样,sn0才会调用snull_open赋值MAC地址。
请问问题出在哪儿了?各位大侠~~~ |
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