Thanks Pablo, comments below.
On 5/9/19 4:57 PM, Pablo Neira Ayuso wrote:
> On Thu, May 09, 2019 at 01:33:58PM +0200, Fernando Fernandez Mancera wrote:
>> This patch introduces the use of nft input files variables in 'jump'
>> statements, e.g.
>>
>> define dest = chainame
>>
>> add rule ip filter input jump $dest
>
> You need two patches to achieve this.
>
> First patch should replace the chain string by an expression, ie.
>
> diff --git a/include/expression.h b/include/expression.h
> index 6416ac090d9f..d3de4abfd435 100644
> --- a/include/expression.h
> +++ b/include/expression.h
> @@ -240,7 +240,7 @@ struct expr {
> struct {
> /* EXPR_VERDICT */
> int verdict;
> - const char *chain;
> + struct expr *chain;
> };
> struct {
> /* EXPR_VALUE */
>
> Then, this first patch should also update the whole codebase to use
> this new chain expression. From the parser, you will have to call
> constant_expr_alloc() using the string_type datatype to store the
> chain string. Still from this initial patch, you also have to call
> expr_evaluate() from stmt_evaluate_verdict() on this new chain
> expression field. You will also need to update the netlink_delinearize
> path to allocate the constant expression so ruleset listing does not
> break
I have been working on this but I am facing a problem with the chain
value. There is a patch below, it compiles but I am getting the
following error. As you can see the chain value is full of random data.
# nft add table ip foo
# nft add chain ip foo bar
# nft add chain ip foo bar2
# nft --debug=eval add rule ip foo bar jump bar2
Evaluate add
add rule ip foo bar jump bar2
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Evaluate verdict
add rule ip foo bar jump bar2
^^^^^^^^^
jump "P5¨$V"
Evaluate verdict
add rule ip foo bar jump bar2
^^^^^^^^^
jump "P5¨$V"
Error: Could not process rule: No such file or directory
add rule ip foo bar jump bar2
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I think that I am missing something when extracting the value with
mpz_get_str(). Thanks!
>From 9299a7e3717d9c9eced1664f8aec1b9b7fa23bda Mon Sep 17 00:00:00 2001
From: Fernando Fernandez Mancera <ffmancera@xxxxxxxxxx>
Date: Sun, 12 May 2019 20:03:29 +0200
Subject: [PATCH] jump: Introduce chain_expr in jump statements
Signed-off-by: Fernando Fernandez Mancera <ffmancera@xxxxxxxxxx>
---
include/expression.h | 4 ++--
src/datatype.c | 6 ++++--
src/evaluate.c | 6 ++++++
src/expression.c | 11 ++++++-----
src/netlink.c | 27 ++++++++++++++++++++-------
src/parser_bison.y | 16 ++++++++++++----
6 files changed, 50 insertions(+), 20 deletions(-)
diff --git a/include/expression.h b/include/expression.h
index 6416ac0..ef41255 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -240,7 +240,7 @@ struct expr {
struct {
/* EXPR_VERDICT */
int verdict;
- const char *chain;
+ struct expr *chain;
};
struct {
/* EXPR_VALUE */
@@ -403,7 +403,7 @@ extern void relational_expr_pctx_update(struct
proto_ctx *ctx,
const struct expr *expr);
extern struct expr *verdict_expr_alloc(const struct location *loc,
- int verdict, const char *chain);
+ int verdict, struct expr *chain);
extern struct expr *symbol_expr_alloc(const struct location *loc,
enum symbol_types type, struct scope *scope,
diff --git a/src/datatype.c b/src/datatype.c
index ac9f2af..bfa5efc 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -262,10 +262,12 @@ static void verdict_type_print(const struct expr
*expr, struct output_ctx *octx)
nft_print(octx, "break");
break;
case NFT_JUMP:
- nft_print(octx, "jump %s", expr->chain);
+ nft_print(octx, "jump ");
+ datatype_print(expr->chain, octx);
break;
case NFT_GOTO:
- nft_print(octx, "goto %s", expr->chain);
+ nft_print(octx, "goto ");
+ datatype_print(expr->chain, octx);
break;
case NFT_RETURN:
nft_print(octx, "return");
diff --git a/src/evaluate.c b/src/evaluate.c
index 3593eb8..c1e612d 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -1940,6 +1940,7 @@ static int stmt_evaluate_arg(struct eval_ctx *ctx,
struct stmt *stmt,
static int stmt_evaluate_verdict(struct eval_ctx *ctx, struct stmt *stmt)
{
+ unsigned int len = NFT_CHAIN_MAXNAMELEN * BITS_PER_BYTE;
if (stmt_evaluate_arg(ctx, stmt, &verdict_type, 0, 0, &stmt->expr) < 0)
return -1;
@@ -1947,6 +1948,11 @@ static int stmt_evaluate_verdict(struct eval_ctx
*ctx, struct stmt *stmt)
case EXPR_VERDICT:
if (stmt->expr->verdict != NFT_CONTINUE)
stmt->flags |= STMT_F_TERMINAL;
+ if (stmt->expr->verdict == NFT_JUMP)
+ stmt->expr->chain = expr_alloc(&stmt->location,
+ EXPR_VALUE, &string_type,
+ BYTEORDER_HOST_ENDIAN,
+ len);
break;
case EXPR_MAP:
break;
diff --git a/src/expression.c b/src/expression.c
index eece12e..55a4ad7 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -207,17 +207,18 @@ static bool verdict_expr_cmp(const struct expr
*e1, const struct expr *e2)
if ((e1->verdict == NFT_JUMP ||
e1->verdict == NFT_GOTO) &&
- strcmp(e1->chain, e2->chain))
- return false;
+ (expr_basetype(e1) == expr_basetype(e2) &&
+ !mpz_cmp(e1->value, e2->value)))
+ return true;
- return true;
+ return false;
}
static void verdict_expr_clone(struct expr *new, const struct expr *expr)
{
new->verdict = expr->verdict;
if (expr->chain != NULL)
- new->chain = xstrdup(expr->chain);
+ mpz_init_set(new->chain->value, expr->chain->value);
}
static void verdict_expr_destroy(struct expr *expr)
@@ -236,7 +237,7 @@ static const struct expr_ops verdict_expr_ops = {
};
struct expr *verdict_expr_alloc(const struct location *loc,
- int verdict, const char *chain)
+ int verdict, struct expr *chain)
{
struct expr *expr;
diff --git a/src/netlink.c b/src/netlink.c
index c051ae6..348a195 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -218,12 +218,15 @@ static void netlink_gen_constant_data(const struct
expr *expr,
static void netlink_gen_verdict(const struct expr *expr,
struct nft_data_linearize *data)
{
+ char *chain;
+
data->verdict = expr->verdict;
switch (expr->verdict) {
case NFT_JUMP:
case NFT_GOTO:
- snprintf(data->chain, NFT_CHAIN_MAXNAMELEN, "%s", expr->chain);
+ chain = mpz_get_str(NULL, 10, expr->chain->value);
+ snprintf(data->chain, NFT_CHAIN_MAXNAMELEN, "%s", chain);
data->chain[NFT_CHAIN_MAXNAMELEN-1] = '\0';
break;
}
@@ -253,19 +256,22 @@ struct expr *netlink_alloc_value(const struct
location *loc,
static struct expr *netlink_alloc_verdict(const struct location *loc,
const struct nft_data_delinearize *nld)
{
- char *chain;
+ struct expr *chain_expr;
switch (nld->verdict) {
case NFT_JUMP:
case NFT_GOTO:
- chain = xstrdup(nld->chain);
+ chain_expr->chain = constant_expr_alloc(loc, &string_type,
+ BYTEORDER_HOST_ENDIAN,
+ sizeof(nld->chain) *
+ BITS_PER_BYTE, nld->chain);
break;
default:
- chain = NULL;
+ chain_expr = NULL;
break;
}
- return verdict_expr_alloc(loc, nld->verdict, chain);
+ return verdict_expr_alloc(loc, nld->verdict, chain_expr);
}
struct expr *netlink_alloc_data(const struct location *loc,
@@ -1153,14 +1159,21 @@ static void trace_print_expr(const struct
nftnl_trace *nlt, unsigned int attr,
static void trace_print_verdict(const struct nftnl_trace *nlt,
struct output_ctx *octx)
{
+ struct expr *chain_expr = NULL;
const char *chain = NULL;
unsigned int verdict;
struct expr *expr;
verdict = nftnl_trace_get_u32(nlt, NFTNL_TRACE_VERDICT);
- if (nftnl_trace_is_set(nlt, NFTNL_TRACE_JUMP_TARGET))
+ if (nftnl_trace_is_set(nlt, NFTNL_TRACE_JUMP_TARGET)) {
chain = xstrdup(nftnl_trace_get_str(nlt, NFTNL_TRACE_JUMP_TARGET));
- expr = verdict_expr_alloc(&netlink_location, verdict, chain);
+ chain_expr = constant_expr_alloc(&netlink_location,
+ &string_type,
+ BYTEORDER_HOST_ENDIAN,
+ sizeof(chain) * BITS_PER_BYTE,
+ chain);
+ }
+ expr = verdict_expr_alloc(&netlink_location, verdict, chain_expr);
nft_print(octx, "verdict ");
expr_print(expr, octx);
diff --git a/src/parser_bison.y b/src/parser_bison.y
index 9aea652..5f61b14 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -618,8 +618,8 @@ int nft_lex(void *, void *, void *);
%type <stmt> meter_stmt meter_stmt_alloc flow_stmt_legacy_alloc
%destructor { stmt_free($$); } meter_stmt meter_stmt_alloc
flow_stmt_legacy_alloc
-%type <expr> symbol_expr verdict_expr integer_expr variable_expr
-%destructor { expr_free($$); } symbol_expr verdict_expr integer_expr
variable_expr
+%type <expr> symbol_expr verdict_expr integer_expr variable_expr
chain_expr
+%destructor { expr_free($$); } symbol_expr verdict_expr integer_expr
variable_expr chain_expr
%type <expr> primary_expr shift_expr and_expr
%destructor { expr_free($$); } primary_expr shift_expr and_expr
%type <expr> exclusive_or_expr inclusive_or_expr
@@ -3827,11 +3827,11 @@ verdict_expr : ACCEPT
{
$$ = verdict_expr_alloc(&@$, NFT_CONTINUE, NULL);
}
- | JUMP identifier
+ | JUMP chain_expr
{
$$ = verdict_expr_alloc(&@$, NFT_JUMP, $2);
}
- | GOTO identifier
+ | GOTO chain_expr
{
$$ = verdict_expr_alloc(&@$, NFT_GOTO, $2);
}
@@ -3841,6 +3841,14 @@ verdict_expr : ACCEPT
}
;
+chain_expr : identifier
+ {
+ $$ = constant_expr_alloc(&@$, &string_type,
+ BYTEORDER_HOST_ENDIAN,
+ sizeof($1) * BITS_PER_BYTE, &$1);
+ }
+ ;
+
meta_expr : META meta_key
{
$$ = meta_expr_alloc(&@$, $2);
--
2.20.1
