netlink_linearize: factor out prefix generation

Add a new netlink_gen_prefix() function that encapsulates the prefix
generation.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index aa44eea5a23e01227222e6ae1908920257bca1f5..a4cd370dc562f7bce55fc1ca3daf88605b885921 100644 (file)
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -290,13 +290,40 @@ static void payload_shift_value(const struct expr *left, struct expr *right)
        mpz_lshift_ui(right->value, left->payload.offset % BITS_PER_BYTE);
 }
 
+static struct expr *netlink_gen_prefix(struct netlink_linearize_ctx *ctx,
+                                      const struct expr *expr,
+                                      enum nft_registers sreg)
+{
+       struct nft_data_linearize nld, zero = {};
+       struct nftnl_expr *nle;
+       mpz_t mask;
+
+       mpz_init(mask);
+       mpz_prefixmask(mask, expr->right->len, expr->right->prefix_len);
+       netlink_gen_raw_data(mask, expr->right->byteorder,
+                            expr->right->len / BITS_PER_BYTE, &nld);
+       mpz_clear(mask);
+
+       zero.len = nld.len;
+
+       nle = alloc_nft_expr("bitwise");
+       netlink_put_register(nle, NFTNL_EXPR_BITWISE_SREG, sreg);
+       netlink_put_register(nle, NFTNL_EXPR_BITWISE_DREG, sreg);
+       nftnl_expr_set_u32(nle, NFTNL_EXPR_BITWISE_LEN, nld.len);
+       nftnl_expr_set(nle, NFTNL_EXPR_BITWISE_MASK, &nld.value, nld.len);
+       nftnl_expr_set(nle, NFTNL_EXPR_BITWISE_XOR, &zero.value, zero.len);
+       nftnl_rule_add_expr(ctx->nlr, nle);
+
+       return expr->right->prefix;
+}
+
 static void netlink_gen_cmp(struct netlink_linearize_ctx *ctx,
                            const struct expr *expr,
                            enum nft_registers dreg)
 {
+       struct nft_data_linearize nld;
        struct nftnl_expr *nle;
        enum nft_registers sreg;
-       struct nft_data_linearize nld, zero = {};
        struct expr *right;
 
        assert(dreg == NFT_REG_VERDICT);
@@ -308,30 +335,12 @@ static void netlink_gen_cmp(struct netlink_linearize_ctx *ctx,
        netlink_gen_expr(ctx, expr->left, sreg);
 
        switch (expr->right->ops->type) {
-       case EXPR_PREFIX: {
-               mpz_t mask;
-
-               mpz_init(mask);
-               mpz_prefixmask(mask, expr->right->len, expr->right->prefix_len);
-               netlink_gen_raw_data(mask, expr->right->byteorder,
-                                    expr->right->len / BITS_PER_BYTE, &nld);
-               mpz_clear(mask);
-
-               zero.len = nld.len;
-
-               nle = alloc_nft_expr("bitwise");
-               netlink_put_register(nle, NFTNL_EXPR_BITWISE_SREG, sreg);
-               netlink_put_register(nle, NFTNL_EXPR_BITWISE_DREG, sreg);
-               nftnl_expr_set_u32(nle, NFTNL_EXPR_BITWISE_LEN, nld.len);
-               nftnl_expr_set(nle, NFTNL_EXPR_BITWISE_MASK, &nld.value, nld.len);
-               nftnl_expr_set(nle, NFTNL_EXPR_BITWISE_XOR, &zero.value, zero.len);
-               nftnl_rule_add_expr(ctx->nlr, nle);
-
-               right = expr->right->prefix;
+       case EXPR_PREFIX:
+               right = netlink_gen_prefix(ctx, expr, sreg);
                break;
-               }
        default:
                right = expr->right;
+               break;
        }
 
        nle = alloc_nft_expr("cmp");