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/include/linux/mroute.h b/include/linux/mroute.h
index 08bc776..d5f6915 100644
--- a/include/linux/mroute.h
+++ b/include/linux/mroute.h
@@ -59,13 +59,18 @@
unsigned char vifc_flags; /* VIFF_ flags */
unsigned char vifc_threshold; /* ttl limit */
unsigned int vifc_rate_limit; /* Rate limiter values (NI) */
- struct in_addr vifc_lcl_addr; /* Our address */
+ union {
+ struct in_addr vifc_lcl_addr; /* Local interface address */
+ int vifc_lcl_ifindex; /* Local interface index */
+ };
struct in_addr vifc_rmt_addr; /* IPIP tunnel addr */
};
-#define VIFF_TUNNEL 0x1 /* IPIP tunnel */
-#define VIFF_SRCRT 0x2 /* NI */
-#define VIFF_REGISTER 0x4 /* register vif */
+#define VIFF_TUNNEL 0x1 /* IPIP tunnel */
+#define VIFF_SRCRT 0x2 /* NI */
+#define VIFF_REGISTER 0x4 /* register vif */
+#define VIFF_USE_IFINDEX 0x8 /* use vifc_lcl_ifindex instead of
+ vifc_lcl_addr to find an interface */
/*
* Cache manipulation structures for mrouted and PIMd