ipmr: Add route table ID to netlink cache reports

Insert the multicast route table ID as a Netlink attribute to Netlink
cache report notifications.

When multiple route tables are in use it is necessary to have a way to
determine which route table a given cache report belongs to when
receiving the cache report.

Signed-off-by: Paul Davey <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/uapi/linux/mroute.h

···
 	IPMRA_CREPORT_SRC_ADDR,
 	IPMRA_CREPORT_DST_ADDR,
 	IPMRA_CREPORT_PKT,
+	IPMRA_CREPORT_TABLE,
 	__IPMRA_CREPORT_MAX
 };
 #define IPMRA_CREPORT_MAX (__IPMRA_CREPORT_MAX - 1)

net/ipv4/ipmr.c

···
 		+ nla_total_size(4)	/* IPMRA_CREPORT_VIF_ID */
 		+ nla_total_size(4)	/* IPMRA_CREPORT_SRC_ADDR */
 		+ nla_total_size(4)	/* IPMRA_CREPORT_DST_ADDR */
+		+ nla_total_size(4)	/* IPMRA_CREPORT_TABLE */
 					/* IPMRA_CREPORT_PKT */
 		+ nla_total_size(payloadlen)
 		;
···
 	    nla_put_in_addr(skb, IPMRA_CREPORT_SRC_ADDR,
 			    msg->im_src.s_addr) ||
 	    nla_put_in_addr(skb, IPMRA_CREPORT_DST_ADDR,
-			    msg->im_dst.s_addr))
+			    msg->im_dst.s_addr) ||
+	    nla_put_u32(skb, IPMRA_CREPORT_TABLE, mrt->id))
 		goto nla_put_failure;
 
 	nla = nla_reserve(skb, IPMRA_CREPORT_PKT, payloadlen);