From: Patrick McHardy <kaber@trash.net>
Date: Sun, 12 Apr 2015 20:10:41 +0000 (+0100)
Subject: netlink_delinearize: introduce register translation helper
X-Git-Tag: v0.5~50^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8ede6005f41afb69e415e1227fc7800308a63819;p=thirdparty%2Fnftables.git

netlink_delinearize: introduce register translation helper

Introduce a helper function to translate register numbers from the kernel
from the compat values to the NFT_REG32 values.

Internally we use the register numbers 0-16:

* 0 is the verdict register in both old and new addressing modes.
* 1-16 are the 32 bit data registers

The NFT_REG32_00 values are mapped to 1-16, the NFT_REG_1-NFT_REG_4
values are each use up 4 registers starting at 1 (1, 5, 9, 13).

Signed-off-by: Patrick McHardy <kaber@trash.net>
---

diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index e9ce76e28..91da85975 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -30,7 +30,7 @@ struct netlink_parse_ctx {
 	struct list_head	*msgs;
 	struct table		*table;
 	struct rule		*rule;
-	struct expr		*registers[NFT_REG_MAX + 1];
+	struct expr		*registers[1 + NFT_REG32_15 - NFT_REG32_00 + 1];
 };
 
 static void __fmtstring(3, 4) netlink_error(struct netlink_parse_ctx *ctx,
@@ -49,14 +49,23 @@ static void __fmtstring(3, 4) netlink_error(struct netlink_parse_ctx *ctx,
 static unsigned int netlink_parse_register(const struct nft_rule_expr *nle,
 					   unsigned int attr)
 {
-	return nft_rule_expr_get_u32(nle, attr);
+	unsigned int reg;
+
+	reg = nft_rule_expr_get_u32(nle, attr);
+	/* Translate 128bit registers to corresponding 32bit registers */
+	if (reg >= NFT_REG_1 && reg <= NFT_REG_4)
+		reg = 1 + (reg - NFT_REG_1) * (NFT_REG_SIZE / NFT_REG32_SIZE);
+	else if (reg >= NFT_REG32_00)
+		reg = 1 + reg - NFT_REG32_00;
+
+	return reg;
 }
 
 static void netlink_set_register(struct netlink_parse_ctx *ctx,
 				 enum nft_registers reg,
 				 struct expr *expr)
 {
-	if (reg > NFT_REG_MAX) {
+	if (reg == NFT_REG_VERDICT || reg > 1 + NFT_REG32_15 - NFT_REG32_00) {
 		netlink_error(ctx, &expr->location,
 			      "Invalid destination register %u", reg);
 		expr_free(expr);
@@ -75,7 +84,7 @@ static struct expr *netlink_get_register(struct netlink_parse_ctx *ctx,
 {
 	struct expr *expr;
 
-	if (reg == NFT_REG_VERDICT || reg > NFT_REG_MAX) {
+	if (reg == NFT_REG_VERDICT || reg > 1 + NFT_REG32_15 - NFT_REG32_00) {
 		netlink_error(ctx, loc, "Invalid source register %u", reg);
 		return NULL;
 	}