hi ravi,
If one is writing for a specific purpose better to follow standard
methods to do it, to avoid possible problems.(it is my personal view)
yes u can as well control using ifconfig instead of chardriver. but how
can u have better control let me know...
Regards
Syed
On Tue, 2004-06-29 at 11:40, Ravi Kumar wrote:
> Hi Syed,
> comments inline
> syedk wrote:
>
> >hi ravi,
> > your net driver doesn't fit into a proper net driver reasons being:
> >
> The driver has no problems except I did not checked the pointer
> reference to oldiph, in one case it was referring to NULL.
>
> >1)what is the char driver doing in a net driver
> >
> Why not we use character device? Infact its not character device in net
> driver but netdevice in a character device. I am creating netdevice from
> a character device. Using Character device, I will have better control
> over netdevice. Alternately it can be controlled using ifconfig.
>
> >2)dev->priv is being typecasted to test_struct and assigned to
> >test_struct c; which itself has net_device variable:
> >
> Yes, I require that dev structure.
>
> >Please remember that dev->priv is used for holding private data like the
> >statistics etc.,
> >
> In my case, its test_struct, The driver is experimental and to prove the
> concept.
>
> > Please go thru skeleton of a sample net driver in
> >
> >/usr/src/linux-2.4.x/drivers/net/pci-skeleton.c
> >/usr/src/linux-2.4.x/drivers/net/loopback.c
> >
> >Hope this helps
> >Regards
> >Syed
> >
> >On Mon, 2004-06-28 at 18:48, Ravi Kumar wrote:
> >
> >
> >>Hi,
> >> I wrote a module to create dummy ethernet device, the intention is to
> >>add it to a bridge and transmit modified packets. I get ethernet device
> >>created but its xmit function is not called when the bridge receives a
> >>packet.
> >>
> >>I feel I have missed some information to register netdevice.
> >>
> >>To add to bridge I did the following:
> >>brctl addbr br0
> >>brctl addif bro eth0
> >>brctl addif br0 firsteth0
> >>ifconfig etho 0.0.0.0
> >>ifconfig bro 172.16.2.100 up
> >>
> >>When I try to add IP address to firsteth0, I get a kernel panic!!
> >>Can we give IP to dummy ethernet device?
> >>
> >>Please help, I am given little time to complete this :( I am attaching
> >>the code for the dummy ethernet device.
> >>-Ravi
> >>----
> >>
> >>
> >>
> >
> >
> >
> >>#ifndef __KERNEL__
> >># define __KERNEL__
> >>#endif
> >>
> >>#ifndef MODULE
> >># define MODULE
> >>#endif
> >>
> >>#define DEVNAME "firsteth"
> >>
> >>#include <linux/module.h>
> >>#include <linux/kernel.h>
> >>#include <linux/fs.h>
> >>#include <linux/slab.h>
> >>
> >>#include <linux/netdevice.h>
> >>#include <linux/if_ether.h>
> >>#include <linux/rtnetlink.h>
> >>#include <linux/if_arp.h>
> >>
> >>/* netfilters related */
> >>#include <linux/netfilter.h>
> >>#include <linux/netfilter_ipv4.h>
> >>
> >>#include <linux/in.h>
> >>#include <linux/udp.h>
> >>#include <net/ip.h>
> >>
> >>int test_open(struct inode *,struct file *);
> >>int test_release(struct inode *,struct file*);
> >>
> >>
> >>struct test_struct{
> >> struct net_device *dev;
> >> char name[IFNAMSIZ];
> >>
> >>};
> >>
> >>struct file_operations test_fop={
> >>llseek: NULL,
> >>read: NULL,
> >>write: NULL,
> >>ioctl: NULL,
> >>open: test_open,
> >>release: test_release,
> >>};
> >>
> >>
> >>struct test_struct pTestStruct;
> >>
> >>
> >>static int testdev_xmit(struct sk_buff *skb, struct net_device *dev)
> >>{
> >> struct iphdr *oldiph;
> >> unsigned char tos=0;
> >> unsigned short df =0;
> >> unsigned char ttl;
> >>
> >> printk(KERN_INFO " In xmit function\n");
> >> oldiph = (skb->protocol==htons(ETH_P_IP))
> >> ? (struct iphdr*)(skb->data+ETH_HLEN)
> >> : NULL;
> >>
> >> tos = oldiph->tos;
> >> df = oldiph->frag_off;
> >> ttl = oldiph->ttl;
> >> printk(KERN_INFO"src IP: %x dst IP: %x , protocol %d \n",ntohl(oldiph->saddr), ntohl(oldiph->daddr),oldiph->protocol);
> >>
> >> return 0;
> >>}
> >>
> >>int test_open(struct inode *inode, struct file *filep)
> >>{
> >> MOD_INC_USE_COUNT;
> >> return 0;
> >>}
> >>
> >>int test_release(struct inode *inode, struct file *filep)
> >>{
> >> MOD_DEC_USE_COUNT;
> >> return 0;
> >>}
> >>
> >>int testdev_open(struct net_device *dev)
> >>{
> >> MOD_INC_USE_COUNT;
> >> return 0;
> >>}
> >>
> >>int testdev_close(struct net_device *dev)
> >>{
> >> unregister_netdev(dev);
> >> MOD_DEC_USE_COUNT;
> >> return 0;
> >>}
> >>//t test_ioctl(struct inode *inode,
> >>static int test_init_dev(struct net_device *dev)
> >>{
> >> struct test_struct *c;
> >>
> >> printk(KERN_INFO "in test_init_dev\n");
> >>
> >> c = (struct test_struct *)dev->priv;
> >> if(!c)
> >> return -ENODEV;
> >>
> >> memset(c,0,sizeof(struct test_struct));
> >> c->dev = dev;
> >>
> >> // ether_setup(dev);
> >> dev->open = testdev_open;
> >> dev->stop = testdev_close;
> >> dev->hard_start_xmit = testdev_xmit;
> >> dev->mtu = ETH_DATA_LEN - sizeof(struct udphdr) - sizeof(struct iphdr) ;
> >> dev_init_buffers(dev);
> >>
> >> printk(KERN_INFO "completed test_init_dev\n");
> >> return 0;
> >>}
> >>
> >>
> >>int init_module(void)
> >>{
> >> int result,i;
> >> struct net_device *tempDev;
> >> struct test_struct *temp_struct;
> >> char devname[25]; // Remove the hardcode
> >>
> >>
> >> for(i=0;i<99;i++)
> >> {
> >> sprintf(devname,"firseth%d",i);
> >> if(__dev_get_by_name(devname) == NULL)
> >> break;
> >> }
> >> if(i==100)
> >> return -ENFILE;
> >> printk(KERN_INFO "********MACOUDP TUNNEL******\n");
> >>
> >> temp_struct = (struct test_struct *)kmalloc(sizeof(struct test_struct),GFP_KERNEL);
> >> if(!temp_struct)
> >> {
> >> printk(KERN_ERR "error in allocating memory\n");
> >> return -ENOMEM;
> >> }
> >> result = register_chrdev(244,"testdrv",&test_fop);
> >> if( result != 0 ){
> >> printk(KERN_WARNING "test: cant get major\n");
> >> return result;
> >> }
> >> i=0;
> >> memset(temp_struct,0,sizeof(struct test_struct));
> >> //sprintf(temp_struct->name, DEVNAME "%d",i);
> >> tempDev = (struct net_device *)kmalloc(sizeof(struct net_device),GFP_KERNEL);
> >> if( !tempDev)
> >> {
> >> printk(KERN_ERR "kmalloc faied\n");
> >> return -ENOMEM;
> >> }
> >> memset(tempDev,0,sizeof(struct net_device));
> >> temp_struct->dev = tempDev;
> >> temp_struct->dev->priv = &pTestStruct;
> >> temp_struct->dev->next = NULL;
> >> temp_struct->dev->base_addr=0;
> >> temp_struct->dev->init = test_init_dev;
> >>
> >> temp_struct->dev->dev_addr[0]=0xFC;
> >> temp_struct->dev->dev_addr[1]=0xFC;
> >> temp_struct->dev->dev_addr[2]=0xA;
> >> temp_struct->dev->dev_addr[3]=0xB;
> >> temp_struct->dev->dev_addr[4]=0xC;
> >> temp_struct->dev->addr_len = ETH_ALEN;
> >> i = dev_alloc_name(temp_struct->dev,"firsteth%d");
> >> if(i < 0 )
> >> {
> >> printk(KERN_ERR "cant allocate device\n");
> >> return -ENODEV;
> >> }
> >> ether_setup(temp_struct->dev);
> >> rtnl_lock();
> >> printk(KERN_INFO "Before calling register_netdevice\n");
> >> i = register_netdevice((temp_struct->dev));
> >> rtnl_unlock();
> >> memcpy(&pTestStruct,temp_struct,sizeof(struct test_struct));
> >> if( i < 0 ){
> >> printk(KERN_ERR "register netdevice failed\n");
> >> return -1;
> >> }
> >> return 0;
> >>}
> >>
> >>void cleanup_module(void)
> >>{
> >> rtnl_lock();
> >> unregister_netdevice(pTestStruct.dev);
> >> rtnl_unlock();
> >> unregister_chrdev(244,"testdrv");
> >>}
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> >--
> >Kernelnewbies: Help each other learn about the Linux kernel.
> >Archive: http://mail.nl.linux.org/kernelnewbies/
> >FAQ: http://kernelnewbies.org/faq/
> >
> >
> >
>
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