Get the IP address of an interface with a given name
Good morning.
I have written a kernel function which needs to get the IP address of
an active network interface
given its name.
The actual implementation i have done is like this
but i suspect this does not always work.
Is there any API already provided by the kernel to do the same?
Thanks a lot
Giacomo
-- actual implementation: ---
/* returns in *addr the internet address having the name ifname */
int get_ifaddr_by_name(const char *ifname, __u32 * addr)
{
struct net_device *pnet_device;
struct in_device *pin_device;
struct in_ifaddr* inet_ifaddr;
read_lock_bh(dev_base_lock);
#if LINUX_VERSION_CODE KERNEL_VERSION(2,6,22)
pnet_device = dev_base;
#else
pnet_device = first_net_device();
#endif
while (pnet_device != NULL)
{
if ((netif_running(pnet_device))
(pnet_device-ip_ptr != NULL)
(strcmp(pnet_device-name, ifname) == 0))
{
pin_device =
(struct in_device *) pnet_device-ip_ptr;
inet_ifaddr = pin_device-ifa_list;
if(inet_ifaddr == NULL)
{
printk(ifa_list is null!\n);
break;
}
/* ifa_local: ifa_address is the remote point in ppp */
*addr = (inet_ifaddr-ifa_local);
read_unlock_bh(dev_base_lock);
return 1;
}
#if LINUX_VERSION_CODE KERNEL_VERSION(2,6,22)
pnet_device = pnet_device-next;
#else
pnet_device = next_net_device(pnet_device);
#endif
}
read_unlock_bh(dev_base_lock);
return -1; /* address not found! */
}
--
Giacomo S.
http://www.giacomos.it
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http://iglu.cc.uniud.it/linuxday
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Re: Get the IP address of an interface with a given name
Giacomo,
Consider using the dev_get_by_name/() kernel method; this is a
simplified example which works with device named eth0 :
struct net_device* device;
struct in_device* in_dev;
struct in_ifaddr* if_info;
device = dev_get_by_name(eth0);
in_dev = (struct in_device *)device-ip_ptr;
if_info = in_dev-ifa_list;
for (;if_info;if_info=if_info-ifa_next)
{
if (!(strcmp(if_info-ifa_label,eth0)))
{
printk(if_info-ifa_address=%x\n,if_info-ifa_address);
break;
}
}
Yous should of course add check for NULL, etc.
Regards,
Rami Rosen
On Nov 20, 2007 10:09 AM, Giacomo [EMAIL PROTECTED] wrote:
Good morning.
I have written a kernel function which needs to get the IP address of
an active network interface
given its name.
The actual implementation i have done is like this
but i suspect this does not always work.
Is there any API already provided by the kernel to do the same?
Thanks a lot
Giacomo
-- actual implementation: ---
/* returns in *addr the internet address having the name ifname */
int get_ifaddr_by_name(const char *ifname, __u32 * addr)
{
struct net_device *pnet_device;
struct in_device *pin_device;
struct in_ifaddr* inet_ifaddr;
read_lock_bh(dev_base_lock);
#if LINUX_VERSION_CODE KERNEL_VERSION(2,6,22)
pnet_device = dev_base;
#else
pnet_device = first_net_device();
#endif
while (pnet_device != NULL)
{
if ((netif_running(pnet_device))
(pnet_device-ip_ptr != NULL)
(strcmp(pnet_device-name, ifname) == 0))
{
pin_device =
(struct in_device *) pnet_device-ip_ptr;
inet_ifaddr = pin_device-ifa_list;
if(inet_ifaddr == NULL)
{
printk(ifa_list is null!\n);
break;
}
/* ifa_local: ifa_address is the remote point in ppp
*/
*addr = (inet_ifaddr-ifa_local);
read_unlock_bh(dev_base_lock);
return 1;
}
#if LINUX_VERSION_CODE KERNEL_VERSION(2,6,22)
pnet_device = pnet_device-next;
#else
pnet_device = next_net_device(pnet_device);
#endif
}
read_unlock_bh(dev_base_lock);
return -1; /* address not found! */
}
--
Giacomo S.
http://www.giacomos.it
- - - - - - - - - - - - - - - - - - - - - -
IPFIREwall (http://www.giacomos.it/ipfire) viene presentato
all'Universita` degli Studi di Udine, il 28 ottobre, in occasione del
Linux Day 2006:
http://iglu.cc.uniud.it/linuxday
- - - - - - - - - - - - - - - - - - - - - -
. '' `.
: :':
`. ` '
`- Debian GNU/Linux -- The power of freedom
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Get the IP address of an interface with a given name
/* returns in *addr the internet address having the name ifname */
int get_ifaddr_by_name(const char *ifname, __u32 * addr)
{
struct net_device *pnet_device;
struct in_device *pin_device;
struct in_ifaddr* inet_ifaddr;
read_lock_bh(dev_base_lock);
#if LINUX_VERSION_CODE KERNEL_VERSION(2,6,22)
pnet_device = dev_base;
#else
pnet_device = first_net_device();
#endif
while (pnet_device != NULL)
{
if ((netif_running(pnet_device))
(pnet_device-ip_ptr != NULL)
(strcmp(pnet_device-name, ifname) == 0))
{
pin_device =
(struct in_device *) pnet_device-ip_ptr;
inet_ifaddr = pin_device-ifa_list;
if(inet_ifaddr == NULL)
{
printk(ifa_list is null!\n);
break;
}
/* ifa_local: ifa_address is the remote point in ppp */
*addr = (inet_ifaddr-ifa_local);
read_unlock_bh(dev_base_lock);
return 1;
}
#if LINUX_VERSION_CODE KERNEL_VERSION(2,6,22)
pnet_device = pnet_device-next;
#else
pnet_device = next_net_device(pnet_device);
#endif
}
read_unlock_bh(dev_base_lock);
return -1; /* address not found! */
}
--
Giacomo S.
http://www.giacomos.it
- - - - - - - - - - - - - - - - - - - - - -
IPFIREwall (http://www.giacomos.it/ipfire) viene presentato
all'Universita` degli Studi di Udine, il 28 ottobre, in occasione del
Linux Day 2006:
http://iglu.cc.uniud.it/linuxday
- - - - - - - - - - - - - - - - - - - - - -
. '' `.
: :':
`. ` '
`- Debian GNU/Linux -- The power of freedom
http://www.debian.org
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the body of a message to [EMAIL PROTECTED]
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