1 files changed, 63 insertions, 14 deletions

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index d30256ac3..1e71ff093 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -778,11 +778,22 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
 			 struct netlink_ext_ack *extack)
 {
 	int err;
+#ifdef CONFIG_NET_CLS_IND
+	int ifindex = -1;
+#endif
 
 	err = tcf_exts_validate(net, tp, tb, est, &n->exts, ovr, extack);
 	if (err < 0)
 		return err;
 
+#ifdef CONFIG_NET_CLS_IND
+	if (tb[TCA_U32_INDEV]) {
+		ifindex = tcf_change_indev(net, tb[TCA_U32_INDEV], extack);
+		if (ifindex < 0)
+			return -EINVAL;
+	}
+#endif
+
 	if (tb[TCA_U32_LINK]) {
 		u32 handle = nla_get_u32(tb[TCA_U32_LINK]);
 		struct tc_u_hnode *ht_down = NULL, *ht_old;
@@ -814,13 +825,8 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
 	}
 
 #ifdef CONFIG_NET_CLS_IND
-	if (tb[TCA_U32_INDEV]) {
-		int ret;
-		ret = tcf_change_indev(net, tb[TCA_U32_INDEV], extack);
-		if (ret < 0)
-			return -EINVAL;
-		n->ifindex = ret;
-	}
+	if (ifindex >= 0)
+		n->ifindex = ifindex;
 #endif
 	return 0;
 }
@@ -873,7 +879,6 @@ static struct tc_u_knode *u32_init_knode(struct tcf_proto *tp,
 	new->ifindex = n->ifindex;
 #endif
 	new->fshift = n->fshift;
-	new->res = n->res;
 	new->flags = n->flags;
 	RCU_INIT_POINTER(new->ht_down, ht);
 
@@ -1061,18 +1066,62 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		return -EINVAL;
 	}
 
+	/* At this point, we need to derive the new handle that will be used to
+	 * uniquely map the identity of this table match entry. The
+	 * identity of the entry that we need to construct is 32 bits made of:
+	 *     htid(12b):bucketid(8b):node/entryid(12b)
+	 *
+	 * At this point _we have the table(ht)_ in which we will insert this
+	 * entry. We carry the table's id in variable "htid".
+	 * Note that earlier code picked the ht selection either by a) the user
+	 * providing the htid specified via TCA_U32_HASH attribute or b) when
+	 * no such attribute is passed then the root ht, is default to at ID
+	 * 0x[800][00][000]. Rule: the root table has a single bucket with ID 0.
+	 * If OTOH the user passed us the htid, they may also pass a bucketid of
+	 * choice. 0 is fine. For example a user htid is 0x[600][01][000] it is
+	 * indicating hash bucketid of 1. Rule: the entry/node ID _cannot_ be
+	 * passed via the htid, so even if it was non-zero it will be ignored.
+	 *
+	 * We may also have a handle, if the user passed one. The handle also
+	 * carries the same addressing of htid(12b):bucketid(8b):node/entryid(12b).
+	 * Rule: the bucketid on the handle is ignored even if one was passed;
+	 * rather the value on "htid" is always assumed to be the bucketid.
+	 */
 	if (handle) {
+		/* Rule: The htid from handle and tableid from htid must match */
 		if (TC_U32_HTID(handle) && TC_U32_HTID(handle ^ htid)) {
 			NL_SET_ERR_MSG_MOD(extack, "Handle specified hash table address mismatch");
 			return -EINVAL;
 		}
-		handle = htid | TC_U32_NODE(handle);
-		err = idr_alloc_u32(&ht->handle_idr, NULL, &handle, handle,
-				    GFP_KERNEL);
-		if (err)
-			return err;
-	} else
+		/* Ok, so far we have a valid htid(12b):bucketid(8b) but we
+		 * need to finalize the table entry identification with the last
+		 * part - the node/entryid(12b)). Rule: Nodeid _cannot be 0_ for
+		 * entries. Rule: nodeid of 0 is reserved only for tables(see
+		 * earlier code which processes TC_U32_DIVISOR attribute).
+		 * Rule: The nodeid can only be derived from the handle (and not
+		 * htid).
+		 * Rule: if the handle specified zero for the node id example
+		 * 0x60000000, then pick a new nodeid from the pool of IDs
+		 * this hash table has been allocating from.
+		 * If OTOH it is specified (i.e for example the user passed a
+		 * handle such as 0x60000123), then we use it generate our final
+		 * handle which is used to uniquely identify the match entry.
+		 */
+		if (!TC_U32_NODE(handle)) {
+			handle = gen_new_kid(ht, htid);
+		} else {
+			handle = htid | TC_U32_NODE(handle);
+			err = idr_alloc_u32(&ht->handle_idr, NULL, &handle,
+					    handle, GFP_KERNEL);
+			if (err)
+				return err;
+		}
+	} else {
+		/* The user did not give us a handle; lets just generate one
+		 * from the table's pool of nodeids.
+		 */
 		handle = gen_new_kid(ht, htid);
+	}
 
 	if (tb[TCA_U32_SEL] == NULL) {
 		NL_SET_ERR_MSG_MOD(extack, "Selector not specified");