add vif using local interface index instead of IP
When routing daemon wants to enable forwarding of multicast traffic it
performs something like:
struct vifctl vc = {
.vifc_vifi = 1,
.vifc_flags = 0,
.vifc_threshold = 1,
.vifc_rate_limit = 0,
.vifc_lcl_addr = ip, /* <--- ip address of physical
interface, e.g. eth0 */
.vifc_rmt_addr.s_addr = htonl(INADDR_ANY),
};
setsockopt(fd, IPPROTO_IP, MRT_ADD_VIF, &vc, sizeof(vc));
This leads (in the kernel) to calling vif_add() function call which
search the (physical) device using assigned IP address:
dev = ip_dev_find(net, vifc->vifc_lcl_addr.s_addr);
The current API (struct vifctl) does not allow to specify an
interface other way than using it's IP, and if there are more than a
single interface with specified IP only the first one will be found.
The attached patch (against 2.6.30.4) allows to specify an interface
by its index, instead of IP address:
struct vifctl vc = {
.vifc_vifi = 1,
.vifc_flags = VIFF_USE_IFINDEX, /* NEW */
.vifc_threshold = 1,
.vifc_rate_limit = 0,
.vifc_lcl_ifindex = if_nametoindex("eth0"), /* NEW */
.vifc_rmt_addr.s_addr = htonl(INADDR_ANY),
};
setsockopt(fd, IPPROTO_IP, MRT_ADD_VIF, &vc, sizeof(vc));
Signed-off-by: Ilia K. <mail4ilia@gmail.com>
=== modified file 'include/linux/mroute.h'
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 630a56d..c757f0b 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -469,8 +469,18 @@
return err;
}
break;
+
+ case VIFF_USE_IFINDEX:
case 0:
- dev = ip_dev_find(net, vifc->vifc_lcl_addr.s_addr);
+ if (vifc->vifc_flags == VIFF_USE_IFINDEX) {
+ dev = dev_get_by_index(net, vifc->vifc_lcl_ifindex);
+ if (dev && dev->ip_ptr == NULL) {
+ dev_put(dev);
+ return -EADDRNOTAVAIL;
+ }
+ } else
+ dev = ip_dev_find(net, vifc->vifc_lcl_addr.s_addr);
+
if (!dev)
return -EADDRNOTAVAIL;
err = dev_set_allmulti(dev, 1);