[nft,v2] libnftables: Store top_scope in struct nft_ctx

Allow for interactive sessions to make use of defines. Since parser is
initialized for each line, top scope defines didn't persist although
they are actually useful for stuff like:

| # nft -i
| goodports = { 22, 23, 80, 443 }
| add rule inet t c tcp dport $goodports accept
| add rule inet t c tcp sport $goodports accept

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
Changes since v1:
- Add missing chunk in src/parser_bison.y. Apparently I managed to edit
  src/parser_bison.c which works perfectly fine until one calls 'make
  clean'.
---
 include/nftables.h                       |  2 ++
 include/parser.h                         |  4 ++--
 src/libnftables.c                        |  8 ++++++--
 src/parser_bison.y                       |  6 +++---
 tests/shell/testcases/nft-i/0001define_0 | 22 ++++++++++++++++++++++
 5 files changed, 35 insertions(+), 7 deletions(-)
 create mode 100755 tests/shell/testcases/nft-i/0001define_0

On Wed, Oct 30, 2019 at 10:28:54PM +0100, Phil Sutter wrote:
> Allow for interactive sessions to make use of defines. Since parser is
> initialized for each line, top scope defines didn't persist although
> they are actually useful for stuff like:
> 
> | # nft -i
> | goodports = { 22, 23, 80, 443 }
   ^
'define' is missing here, right?

> | add rule inet t c tcp dport $goodports accept
> | add rule inet t c tcp sport $goodports accept
> 
> Signed-off-by: Phil Sutter <phil@nwl.cc>

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

One more comment, possible follow up, just an idea.

> diff --git a/src/libnftables.c b/src/libnftables.c
> index e20372438db62..7c35e898d87ab 100644
> --- a/src/libnftables.c
> +++ b/src/libnftables.c
> @@ -155,6 +155,8 @@ struct nft_ctx *nft_ctx_new(uint32_t flags)
>  	nft_ctx_add_include_path(ctx, DEFAULT_INCLUDE_PATH);
>  	ctx->parser_max_errors	= 10;
>  	init_list_head(&ctx->cache.list);
> +	ctx->top_scope = xzalloc(sizeof(struct scope));
> +	init_list_head(&ctx->top_scope->symbols);

Probably add scope_alloc()

>  	ctx->flags = flags;
>  	ctx->output.output_fp = stdout;
>  	ctx->output.error_fp = stderr;
> @@ -292,6 +294,8 @@ void nft_ctx_free(struct nft_ctx *ctx)
>  	iface_cache_release();
>  	cache_release(&ctx->cache);
>  	nft_ctx_clear_include_paths(ctx);
> +	scope_release(ctx->top_scope);
> +	xfree(ctx->top_scope);

and scope_free().

>  	xfree(ctx->state);
>  	nft_exit(ctx);
>  	xfree(ctx);
> @@ -368,7 +372,7 @@ static int nft_parse_bison_buffer(struct nft_ctx *nft, const char *buf,
>  {
>  	int ret;
>  
> -	parser_init(nft, nft->state, msgs, cmds);
> +	parser_init(nft, nft->state, msgs, cmds, nft->top_scope);
>  	nft->scanner = scanner_init(nft->state);
>  	scanner_push_buffer(nft->scanner, &indesc_cmdline, buf);
>  
> @@ -384,7 +388,7 @@ static int nft_parse_bison_filename(struct nft_ctx *nft, const char *filename,
>  {
>  	int ret;
>  
> -	parser_init(nft, nft->state, msgs, cmds);
> +	parser_init(nft, nft->state, msgs, cmds, nft->top_scope);
>  	nft->scanner = scanner_init(nft->state);
>  	if (scanner_read_file(nft, filename, &internal_location) < 0)
>  		return -1;
> diff --git a/src/parser_bison.y b/src/parser_bison.y
> index 7f9b1752f41d4..b73cf3bcfb209 100644
> --- a/src/parser_bison.y
> +++ b/src/parser_bison.y
> @@ -42,13 +42,13 @@
>  #include "parser_bison.h"
>  
>  void parser_init(struct nft_ctx *nft, struct parser_state *state,
> -		 struct list_head *msgs, struct list_head *cmds)
> +		 struct list_head *msgs, struct list_head *cmds,
> +		 struct scope *top_scope)
>  {
>  	memset(state, 0, sizeof(*state));
> -	init_list_head(&state->top_scope.symbols);
>  	state->msgs = msgs;
>  	state->cmds = cmds;
> -	state->scopes[0] = scope_init(&state->top_scope, NULL);
> +	state->scopes[0] = scope_init(top_scope, NULL);
>  	init_list_head(&state->indesc_list);
>  }
>  
> diff --git a/tests/shell/testcases/nft-i/0001define_0 b/tests/shell/testcases/nft-i/0001define_0
> new file mode 100755
> index 0000000000000..62e1b6dede21d
> --- /dev/null
> +++ b/tests/shell/testcases/nft-i/0001define_0
> @@ -0,0 +1,22 @@
> +#!/bin/bash
> +
> +set -e
> +
> +# test if using defines in interactive nft sessions works
> +
> +$NFT -i >/dev/null <<EOF
> +add table inet t
> +add chain inet t c
> +define ports = { 22, 443 }
> +add rule inet t c tcp dport \$ports accept
> +add rule inet t c udp dport \$ports accept
> +EOF
> +
> +$NFT -i >/dev/null <<EOF
> +define port = 22
> +flush chain inet t c
> +redefine port = 443
> +delete chain inet t c
> +undefine port
> +delete table inet t
> +EOF
> -- 
> 2.23.0
>

Hi Pablo,

On Wed, Nov 06, 2019 at 01:40:17PM +0100, Pablo Neira Ayuso wrote:
> On Wed, Oct 30, 2019 at 10:28:54PM +0100, Phil Sutter wrote:
> > Allow for interactive sessions to make use of defines. Since parser is
> > initialized for each line, top scope defines didn't persist although
> > they are actually useful for stuff like:
> > 
> > | # nft -i
> > | goodports = { 22, 23, 80, 443 }
>    ^
> 'define' is missing here, right?

Oh yes, of course.

> > | add rule inet t c tcp dport $goodports accept
> > | add rule inet t c tcp sport $goodports accept
> > 
> > Signed-off-by: Phil Sutter <phil@nwl.cc>
> 
> Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
> 
> One more comment, possible follow up, just an idea.

Added those, sent v2 just to be sure.

Thanks, Phil