[PATCH nft,v2 1/3] src: fix reset element support for interval set type

[Pablo Neira Ayuso <pablo@netfilter.org>]

From: Florian Westphal <fw@strlen.de>

Running reset command yields on an interval (rbtree) set yields:
nft reset element inet filter rbtreeset {1.2.3.4}
BUG: unhandled op 8

This is easy to fix, CMD_RESET doesn't add or remove so it should be
treated like CMD_GET.

Unfortunately, this still doesn't work properly:

nft get element inet filter rbset {1.2.3.4}
returns:
 ... elements = { 1.2.3.4 }

but its expected that "get" and "reset" also return stateful objects
associated with the element.  This works for other set types, but for
rbtree, the list of statements gets lost during segtree processing.

After fix, get/reset returns:
  elements = { 1.2.3.4 counter packets 10 ...

A follow up patch will add a test case.

Fixes: 83e0f4402fb7 ("Implement 'reset {set,map,element}' commands")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
v2: while at this, fix maps too.

@Florian: This is a follow-up on top of your series.

 src/evaluate.c |  1 +
 src/segtree.c  | 36 ++++++++++++++++++++++++++++++------
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/evaluate.c b/src/evaluate.c
index c9c56588cee4..e27d08ce7ef8 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -1953,6 +1953,7 @@ static int interval_set_eval(struct eval_ctx *ctx, struct set *set,
 				 ctx->nft->debug_mask);
 		break;
 	case CMD_GET:
+	case CMD_RESET:
 		break;
 	default:
 		BUG("unhandled op %d\n", ctx->cmd->op);
diff --git a/src/segtree.c b/src/segtree.c
index 2e32a3291979..bce38eef293c 100644
--- a/src/segtree.c
+++ b/src/segtree.c
@@ -206,6 +206,27 @@ static struct expr *expr_to_set_elem(struct expr *e)
 	return __expr_to_set_elem(e, expr);
 }
 
+static void set_compound_expr_add(struct expr *compound, struct expr *expr, struct expr *orig)
+{
+	struct expr *elem;
+
+	switch (expr->etype) {
+	case EXPR_SET_ELEM:
+		list_splice_init(&orig->stmt_list, &expr->stmt_list);
+		compound_expr_add(compound, expr);
+		break;
+	case EXPR_MAPPING:
+		list_splice_init(&orig->left->stmt_list, &expr->left->stmt_list);
+		compound_expr_add(compound, expr);
+		break;
+	default:
+		elem = set_elem_expr_alloc(&orig->location, expr);
+		list_splice_init(&orig->stmt_list, &elem->stmt_list);
+		compound_expr_add(compound, elem);
+		break;
+	}
+}
+
 int get_set_decompose(struct set *cache_set, struct set *set)
 {
 	struct expr *i, *next, *range;
@@ -227,20 +248,23 @@ int get_set_decompose(struct set *cache_set, struct set *set)
 				errno = ENOENT;
 				return -1;
 			}
+
+			set_compound_expr_add(new_init, range, left);
+
 			expr_free(left);
 			expr_free(i);
 
-			compound_expr_add(new_init, range);
 			left = NULL;
 		} else {
 			if (left) {
 				range = get_set_interval_find(cache_set,
 							      left, NULL);
+
 				if (range)
-					compound_expr_add(new_init, range);
+					set_compound_expr_add(new_init, range, left);
 				else
-					compound_expr_add(new_init,
-							  expr_to_set_elem(left));
+					set_compound_expr_add(new_init,
+							      expr_to_set_elem(left), left);
 			}
 			left = i;
 		}
@@ -248,9 +272,9 @@ int get_set_decompose(struct set *cache_set, struct set *set)
 	if (left) {
 		range = get_set_interval_find(cache_set, left, NULL);
 		if (range)
-			compound_expr_add(new_init, range);
+			set_compound_expr_add(new_init, range, left);
 		else
-			compound_expr_add(new_init, expr_to_set_elem(left));
+			set_compound_expr_add(new_init, expr_to_set_elem(left), left);
 	}
 
 	expr_free(set->init);
-- 
2.30.2