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List: netfilter-devel
Subject: [PATCH nft v5 2/8] netlink_delinearize: refactor stmt_payload_binop_postprocess
From: Jeremy Sowden <jeremy () azazel ! net>
Date: 2023-05-28 14:00:52
Message-ID: 20230528140058.1218669-3-jeremy () azazel ! net
[Download RAW message or body]
We are about to add support for a new payload binop that needs to be
post-processed, so move the contents of the two major cases (I and II)
into separate functions to keep the function size reasonable.
Fix a typo in a comment while we're at it.
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
---
src/netlink_delinearize.c | 193 +++++++++++++++++++++-----------------
1 file changed, 109 insertions(+), 84 deletions(-)
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index bdd3242bf5ec..d729fb85a3ed 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -3112,6 +3112,110 @@ static void stmt_payload_binop_pp(struct rule_pp_ctx *ctx, struct expr *binop)
}
}
+static bool stmt_payload_binop_postprocess_i(struct rule_pp_ctx *ctx)
+{
+ struct expr *expr, *binop, *payload, *value, *mask;
+ struct stmt *stmt = ctx->stmt;
+ mpz_t tmp, bitmask;
+
+ expr = stmt->payload.val;
+
+ if (expr->op != OP_OR)
+ return false;
+
+ value = expr->right;
+ if (value->etype != EXPR_VALUE)
+ return false;
+
+ binop = expr->left;
+ if (binop->op != OP_AND)
+ return false;
+
+ payload = binop->left;
+ if (payload->etype != EXPR_PAYLOAD)
+ return false;
+
+ if (!payload_expr_cmp(stmt->payload.expr, payload))
+ return false;
+
+ mask = binop->right;
+ if (mask->etype != EXPR_VALUE)
+ return false;
+
+ mpz_init(tmp);
+ mpz_set(tmp, mask->value);
+
+ mpz_init_bitmask(bitmask, payload->len);
+ mpz_xor(bitmask, bitmask, mask->value);
+ mpz_xor(bitmask, bitmask, value->value);
+ mpz_set(mask->value, bitmask);
+ mpz_clear(bitmask);
+
+ binop_postprocess(ctx, expr, &expr->left);
+ if (!payload_is_known(payload))
+ mpz_set(mask->value, tmp);
+ else {
+ expr_free(stmt->payload.expr);
+ stmt->payload.expr = expr_get(payload);
+ stmt->payload.val = expr_get(expr->right);
+ expr_free(expr);
+ }
+
+ mpz_clear(tmp);
+
+ return true;
+}
+
+static bool stmt_payload_binop_postprocess_ii(struct rule_pp_ctx *ctx)
+{
+ struct expr *expr, *payload, *value;
+ struct stmt *stmt = ctx->stmt;
+ mpz_t bitmask;
+
+ expr = stmt->payload.val;
+
+ value = expr->right;
+ if (value->etype != EXPR_VALUE)
+ return false;
+
+ switch (expr->op) {
+ case OP_AND: /* IIa */
+ payload = expr->left;
+ mpz_init_bitmask(bitmask, payload->len);
+ mpz_xor(bitmask, bitmask, value->value);
+ mpz_set(value->value, bitmask);
+ mpz_clear(bitmask);
+ break;
+ case OP_OR: /* IIb */
+ break;
+ default: /* No idea */
+ return false;
+ }
+
+ stmt_payload_binop_pp(ctx, expr);
+ if (!payload_is_known(expr->left))
+ return false;
+
+ expr_free(stmt->payload.expr);
+
+ switch (expr->op) {
+ case OP_AND:
+ /* Mask was used to match payload, i.e.
+ * user asked to set zero value.
+ */
+ mpz_set_ui(value->value, 0);
+ break;
+ default:
+ break;
+ }
+
+ stmt->payload.expr = expr_get(expr->left);
+ stmt->payload.val = expr_get(expr->right);
+ expr_free(expr);
+
+ return true;
+}
+
/**
* stmt_payload_binop_postprocess - decode payload set binop
*
@@ -3128,7 +3232,7 @@ static void stmt_payload_binop_pp(struct rule_pp_ctx *ctx, struct expr *binop)
* a binop expression with a munged payload expression on the left
* and a mask to clear the real payload offset/length.
*
- * So chech if we have one of the following binops:
+ * So check if we have one of the following binops:
* I)
* binop (|)
* binop(&) value/set
@@ -3156,9 +3260,8 @@ static void stmt_payload_binop_pp(struct rule_pp_ctx *ctx, struct expr *binop)
*/
static void stmt_payload_binop_postprocess(struct rule_pp_ctx *ctx)
{
- struct expr *expr, *binop, *payload, *value, *mask;
+ struct expr *expr;
struct stmt *stmt = ctx->stmt;
- mpz_t bitmask;
expr = stmt->payload.val;
@@ -3166,93 +3269,15 @@ static void stmt_payload_binop_postprocess(struct rule_pp_ctx *ctx)
return;
switch (expr->left->etype) {
- case EXPR_BINOP: {/* I? */
- mpz_t tmp;
-
- if (expr->op != OP_OR)
- return;
-
- value = expr->right;
- if (value->etype != EXPR_VALUE)
- return;
-
- binop = expr->left;
- if (binop->op != OP_AND)
- return;
-
- payload = binop->left;
- if (payload->etype != EXPR_PAYLOAD)
- return;
-
- if (!payload_expr_cmp(stmt->payload.expr, payload))
- return;
-
- mask = binop->right;
- if (mask->etype != EXPR_VALUE)
- return;
-
- mpz_init(tmp);
- mpz_set(tmp, mask->value);
-
- mpz_init_bitmask(bitmask, payload->len);
- mpz_xor(bitmask, bitmask, mask->value);
- mpz_xor(bitmask, bitmask, value->value);
- mpz_set(mask->value, bitmask);
- mpz_clear(bitmask);
-
- binop_postprocess(ctx, expr, &expr->left);
- if (!payload_is_known(payload)) {
- mpz_set(mask->value, tmp);
- mpz_clear(tmp);
+ case EXPR_BINOP: /* I? */
+ if (stmt_payload_binop_postprocess_i(ctx))
return;
- }
- mpz_clear(tmp);
- expr_free(stmt->payload.expr);
- stmt->payload.expr = expr_get(payload);
- stmt->payload.val = expr_get(expr->right);
- expr_free(expr);
break;
- }
case EXPR_PAYLOAD: /* II? */
- value = expr->right;
- if (value->etype != EXPR_VALUE)
- return;
-
- switch (expr->op) {
- case OP_AND: /* IIa */
- payload = expr->left;
- mpz_init_bitmask(bitmask, payload->len);
- mpz_xor(bitmask, bitmask, value->value);
- mpz_set(value->value, bitmask);
- mpz_clear(bitmask);
- break;
- case OP_OR: /* IIb */
- break;
- default: /* No idea */
- return;
- }
-
- stmt_payload_binop_pp(ctx, expr);
- if (!payload_is_known(expr->left))
+ if (stmt_payload_binop_postprocess_ii(ctx))
return;
- expr_free(stmt->payload.expr);
-
- switch (expr->op) {
- case OP_AND:
- /* Mask was used to match payload, i.e.
- * user asked to set zero value.
- */
- mpz_set_ui(value->value, 0);
- break;
- default:
- break;
- }
-
- stmt->payload.expr = expr_get(expr->left);
- stmt->payload.val = expr_get(expr->right);
- expr_free(expr);
break;
default: /* No idea */
break;
--
2.39.2
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