From: Florian Westphal <fw@strlen.de>
Date: Sun, 25 Feb 2018 18:46:04 +0000 (+0100)
Subject: src: make raw payloads work
X-Git-Tag: v0.8.3~24
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=e277fa7d015bd3f5d5d20be2c5adc4723f1867b2;p=thirdparty%2Fnftables.git

src: make raw payloads work

make syntax consistent between print and parse.
No dependency handling -- once you use raw expression, you need
to make sure the raw expression only sees the packets that you'd
want it to see.

based on an earlier patch from Laurent Fasnacht <l@libres.ch>.
Laurents patch added a different syntax:
   @<protocol>,<base>,<data type>,<offset>,<length>

data_type is useful to make nftables not err when
asking for "@payload,32,32 192.168.0.1", this patch still requires
manual convsersion to an integer type (hex or decimal notation).

data_type should probably be added later by adding an explicit
cast expression, independent of the raw payload syntax.

Signed-off-by: Florian Westphal <fw@strlen.de>
---

diff --git a/include/expression.h b/include/expression.h
index 0a0e178fe..26182120f 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -279,6 +279,7 @@ struct expr {
 			const struct proto_hdr_template	*tmpl;
 			enum proto_bases		base;
 			unsigned int			offset;
+			bool				is_raw;
 		} payload;
 		struct {
 			/* EXPR_EXTHDR */
diff --git a/src/evaluate.c b/src/evaluate.c
index c98749d92..6be3bf031 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -609,6 +609,9 @@ static int __expr_evaluate_payload(struct eval_ctx *ctx, struct expr *expr)
 	struct stmt *nstmt;
 	int err;
 
+	if (expr->ops->type == EXPR_PAYLOAD && expr->payload.is_raw)
+		return 0;
+
 	desc = ctx->pctx.protocol[base].desc;
 	if (desc == NULL) {
 		if (payload_gen_dependency(ctx, payload, &nstmt) < 0)
diff --git a/src/parser_bison.y b/src/parser_bison.y
index 563411155..ec8b0dd89 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -3465,6 +3465,9 @@ payload_raw_expr	:	AT	payload_base_spec	COMMA	NUM	COMMA	NUM
 				$$->payload.offset	= $4;
 				$$->len			= $6;
 				$$->dtype		= &integer_type;
+				$$->byteorder		= BYTEORDER_BIG_ENDIAN;
+				$$->payload.is_raw	= true;
+				$$->flags		= 0;
 			}
 			;
 
diff --git a/src/payload.c b/src/payload.c
index ef437b440..09665a0e8 100644
--- a/src/payload.c
+++ b/src/payload.c
@@ -48,7 +48,7 @@ static void payload_expr_print(const struct expr *expr, struct output_ctx *octx)
 	if (payload_is_known(expr))
 		nft_print(octx, "%s %s", desc->name, tmpl->token);
 	else
-		nft_print(octx, "payload @%s,%u,%u",
+		nft_print(octx, "@%s,%u,%u",
 			  proto_base_tokens[expr->payload.base],
 			  expr->payload.offset, expr->len);
 }