net: sched: cls_u32: add extack support

This patch adds extack support for the u32 classifier as example for
delete and init callback.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index e8963ed358997641f92755977f9c62383996372a..57113e93615584d5bc747bc0aba6a1dceae0f5bf 100644 (file)
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -689,13 +689,16 @@ static int u32_delete(struct tcf_proto *tp, void *arg, bool *last,
                goto out;
        }
 
-       if (root_ht == ht)
+       if (root_ht == ht) {
+               NL_SET_ERR_MSG_MOD(extack, "Not allowed to delete root node");
                return -EINVAL;
+       }
 
        if (ht->refcnt == 1) {
                ht->refcnt--;
                u32_destroy_hnode(tp, ht);
        } else {
+               NL_SET_ERR_MSG_MOD(extack, "Can not delete in-use filter");
                return -EBUSY;
        }
 
@@ -779,14 +782,18 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
                u32 handle = nla_get_u32(tb[TCA_U32_LINK]);
                struct tc_u_hnode *ht_down = NULL, *ht_old;
 
-               if (TC_U32_KEY(handle))
+               if (TC_U32_KEY(handle)) {
+                       NL_SET_ERR_MSG_MOD(extack, "u32 Link handle must be a hash table");
                        return -EINVAL;
+               }
 
                if (handle) {
                        ht_down = u32_lookup_ht(ht->tp_c, handle);
 
-                       if (!ht_down)
+                       if (!ht_down) {
+                               NL_SET_ERR_MSG_MOD(extack, "Link hash table not found");
                                return -EINVAL;
+                       }
                        ht_down->refcnt++;
                }
 
@@ -910,28 +917,40 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
        size_t size;
 #endif
 
-       if (!opt)
-               return handle ? -EINVAL : 0;
+       if (!opt) {
+               if (handle) {
+                       NL_SET_ERR_MSG_MOD(extack, "Filter handle requires options");
+                       return -EINVAL;
+               } else {
+                       return 0;
+               }
+       }
 
-       err = nla_parse_nested(tb, TCA_U32_MAX, opt, u32_policy, NULL);
+       err = nla_parse_nested(tb, TCA_U32_MAX, opt, u32_policy, extack);
        if (err < 0)
                return err;
 
        if (tb[TCA_U32_FLAGS]) {
                flags = nla_get_u32(tb[TCA_U32_FLAGS]);
-               if (!tc_flags_valid(flags))
+               if (!tc_flags_valid(flags)) {
+                       NL_SET_ERR_MSG_MOD(extack, "Invalid filter flags");
                        return -EINVAL;
+               }
        }
 
        n = *arg;
        if (n) {
                struct tc_u_knode *new;
 
-               if (TC_U32_KEY(n->handle) == 0)
+               if (TC_U32_KEY(n->handle) == 0) {
+                       NL_SET_ERR_MSG_MOD(extack, "Key node id cannot be zero");
                        return -EINVAL;
+               }
 
-               if (n->flags != flags)
+               if (n->flags != flags) {
+                       NL_SET_ERR_MSG_MOD(extack, "Key node flags do not match passed flags");
                        return -EINVAL;
+               }
 
                new = u32_init_knode(tp, n);
                if (!new)
@@ -965,10 +984,14 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
        if (tb[TCA_U32_DIVISOR]) {
                unsigned int divisor = nla_get_u32(tb[TCA_U32_DIVISOR]);
 
-               if (--divisor > 0x100)
+               if (--divisor > 0x100) {
+                       NL_SET_ERR_MSG_MOD(extack, "Exceeded maximum 256 hash buckets");
                        return -EINVAL;
-               if (TC_U32_KEY(handle))
+               }
+               if (TC_U32_KEY(handle)) {
+                       NL_SET_ERR_MSG_MOD(extack, "Divisor can only be used on a hash table");
                        return -EINVAL;
+               }
                ht = kzalloc(sizeof(*ht) + divisor*sizeof(void *), GFP_KERNEL);
                if (ht == NULL)
                        return -ENOBUFS;
@@ -1014,20 +1037,26 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
                        htid = ht->handle;
                } else {
                        ht = u32_lookup_ht(tp->data, TC_U32_HTID(htid));
-                       if (!ht)
+                       if (!ht) {
+                               NL_SET_ERR_MSG_MOD(extack, "Specified hash table not found");
                                return -EINVAL;
+                       }
                }
        } else {
                ht = rtnl_dereference(tp->root);
                htid = ht->handle;
        }
 
-       if (ht->divisor < TC_U32_HASH(htid))
+       if (ht->divisor < TC_U32_HASH(htid)) {
+               NL_SET_ERR_MSG_MOD(extack, "Specified hash table buckets exceed configured value");
                return -EINVAL;
+       }
 
        if (handle) {
-               if (TC_U32_HTID(handle) && TC_U32_HTID(handle ^ htid))
+               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_ext(&ht->handle_idr, NULL, NULL,
                                    handle, handle + 1,
@@ -1038,6 +1067,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
                handle = gen_new_kid(ht, htid);
 
        if (tb[TCA_U32_SEL] == NULL) {
+               NL_SET_ERR_MSG_MOD(extack, "Selector not specified");
                err = -EINVAL;
                goto erridr;
        }