[PATCH nft,v3] mergesort: find base value expression type via recursion

[PATCH nft,v3] mergesort: find base value expression type via recursion

[Pablo Neira Ayuso]

Sets that store flags might contain a mixture of values and binary
operations. Find the base value type via recursion to compare the
expressions.

Fixes: 14ee0a979b62 ("src: sort set elements in netlink_get_setelems()")
Fixes: 3926a3369bb5 ("mergesort: unbreak listing with binops")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
v3: simplify concatenation, take first component of the tuple as key for sorting

 src/mergesort.c                               | 49 ++++++++-----------
 tests/shell/testcases/sets/0055tcpflags_0     | 27 ++++++++++
 .../testcases/sets/dumps/0055tcpflags_0.nft   | 10 ++++
 3 files changed, 57 insertions(+), 29 deletions(-)
 create mode 100755 tests/shell/testcases/sets/0055tcpflags_0
 create mode 100644 tests/shell/testcases/sets/dumps/0055tcpflags_0.nft

diff --git a/src/mergesort.c b/src/mergesort.c
index 02094b486aeb..f938a11d7c40 100644
--- a/src/mergesort.c
+++ b/src/mergesort.c
@@ -13,43 +13,34 @@
 
 static int expr_msort_cmp(const struct expr *e1, const struct expr *e2);
 
-static int concat_expr_msort_cmp(const struct expr *e1, const struct expr *e2)
+static const struct expr *expr_msort_value(const struct expr *expr)
 {
-	struct list_head *l = (&e2->expressions)->next;
-	const struct expr *i1, *i2;
-	int ret;
-
-	list_for_each_entry(i1, &e1->expressions, list) {
-		i2 = list_entry(l, typeof(struct expr), list);
-
-		ret = expr_msort_cmp(i1, i2);
-		if (ret)
-			return ret;
-
-		l = l->next;
-	}
-
-	return false;
-}
-
-static int expr_msort_cmp(const struct expr *e1, const struct expr *e2)
-{
-	switch (e1->etype) {
+	switch (expr->etype) {
 	case EXPR_SET_ELEM:
-		return expr_msort_cmp(e1->key, e2->key);
+		return expr_msort_value(expr->key);
+	case EXPR_BINOP:
+	case EXPR_MAPPING:
+		return expr_msort_value(expr->left);
 	case EXPR_VALUE:
-		return mpz_cmp(e1->value, e2->value);
+		return expr;
 	case EXPR_CONCAT:
-		return concat_expr_msort_cmp(e1, e2);
-	case EXPR_MAPPING:
-		return expr_msort_cmp(e1->left, e2->left);
-	case EXPR_BINOP:
-		return expr_msort_cmp(e1->left, e2->left);
+		expr = list_first_entry(&expr->expressions, struct expr, list);
+		return expr_msort_value(expr);
 	default:
-		BUG("Unknown expression %s\n", expr_name(e1));
+		BUG("Unknown expression %s\n", expr_name(expr));
 	}
 }
 
+static int expr_msort_cmp(const struct expr *e1, const struct expr *e2)
+{
+	e1 = expr_msort_value(e1);
+	e2 = expr_msort_value(e2);
+
+	assert(e1->etype == e2->etype && e1->etype == EXPR_VALUE);
+
+	return mpz_cmp(e1->value, e2->value);
+}
+
 static void list_splice_sorted(struct list_head *list, struct list_head *head)
 {
 	struct list_head *h = head->next;
diff --git a/tests/shell/testcases/sets/0055tcpflags_0 b/tests/shell/testcases/sets/0055tcpflags_0
new file mode 100755
index 000000000000..a2b24eb2981b
--- /dev/null
+++ b/tests/shell/testcases/sets/0055tcpflags_0
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+EXPECTED="add table ip test
+
+add set ip test tcp_good_flags { type tcp_flag ; flags constant ; elements = {
+  ( 0 | 0 | 0 |ack| 0 | 0 ),  \
+  ( 0 | 0 | 0 |ack| 0 |urg),  \
+  ( 0 | 0 | 0 |ack|psh| 0 ),  \
+  ( 0 | 0 | 0 |ack|psh|urg),  \
+  ( 0 | 0 |rst| 0 | 0 | 0 ),  \
+  ( 0 | 0 |rst|ack| 0 | 0 ),  \
+  ( 0 | 0 |rst|ack| 0 |urg),  \
+  ( 0 | 0 |rst|ack|psh| 0 ),  \
+  ( 0 | 0 |rst|ack|psh|urg),  \
+  ( 0 |syn| 0 | 0 | 0 | 0 ),  \
+  ( 0 |syn| 0 |ack| 0 | 0 ),  \
+  ( 0 |syn| 0 |ack| 0 |urg),  \
+  ( 0 |syn| 0 |ack|psh| 0 ),  \
+  ( 0 |syn| 0 |ack|psh|urg),  \
+  (fin| 0 | 0 |ack| 0 | 0 ),  \
+  (fin| 0 | 0 |ack| 0 |urg),  \
+  (fin| 0 | 0 |ack|psh| 0 ),  \
+  (fin| 0 | 0 |ack|psh|urg)   \
+} ; }"
+
+set -e
+$NFT -f - <<< $EXPECTED
diff --git a/tests/shell/testcases/sets/dumps/0055tcpflags_0.nft b/tests/shell/testcases/sets/dumps/0055tcpflags_0.nft
new file mode 100644
index 000000000000..ffed5426577e
--- /dev/null
+++ b/tests/shell/testcases/sets/dumps/0055tcpflags_0.nft
@@ -0,0 +1,10 @@
+table ip test {
+	set tcp_good_flags {
+		type tcp_flag
+		flags constant
+		elements = { fin | psh | ack | urg, fin | psh | ack, fin | ack | urg, fin | ack, syn | psh | ack | urg,
+			     syn | psh | ack, syn | ack | urg, syn | ack, syn, rst | psh | ack | urg,
+			     rst | psh | ack, rst | ack | urg, rst | ack, rst, psh | ack | urg,
+			     psh | ack, ack | urg, ack }
+	}
+}
-- 
2.20.1