tcpopt: split tcpopt_hdr_fields into per-option enum

Currently we're limited to ten template fields in exthdr_desc struct.
Using a single enum for all tpc option fields thus won't work
indefinitely (TCPOPTHDR_FIELD_TSECR is 9) when new option templates get
added.

Fortunately we can just use one enum per tcp option to avoid this.
As a side effect this also allows to simplify the sack offset
calculations.  Rather than computing that on-the-fly, just add extra
fields to the SACK template.

expr->exthdr.offset now holds the 'raw' value, filled in from the option
template. This would ease implementation of 'raw option matching'
using offset and length to load from the option.

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

1 files changed, 32 insertions, 4 deletions

diff --git a/src/parser_json.c b/src/parser_json.c
index c68b64d9..6e133365 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -468,8 +468,10 @@ static int json_parse_tcp_option_type(const char *name, int *val)
 	}
 	/* special case for sack0 - sack3 */
 	if (sscanf(name, "sack%u", &i) == 1 && i < 4) {
-		if (val)
-			*val = TCPOPT_KIND_SACK + i;
+		if (val && i == 0)
+			*val = TCPOPT_KIND_SACK;
+		else if (val && i > 0)
+			*val = TCPOPT_KIND_SACK1 + i - 1;
 		return 0;
 	}
 	return 1;
@@ -477,12 +479,38 @@ static int json_parse_tcp_option_type(const char *name, int *val)
 
 static int json_parse_tcp_option_field(int type, const char *name, int *val)
 {
+	const struct exthdr_desc *desc;
+	unsigned int block = 0;
 	unsigned int i;
-	const struct exthdr_desc *desc = tcpopt_protocols[type];
+
+	switch (type) {
+	case TCPOPT_KIND_SACK1:
+		type = TCPOPT_KIND_SACK;
+		block = 1;
+		break;
+	case TCPOPT_KIND_SACK2:
+		type = TCPOPT_KIND_SACK;
+		block = 2;
+		break;
+	case TCPOPT_KIND_SACK3:
+		type = TCPOPT_KIND_SACK;
+		block = 3;
+		break;
+	}
+
+	if (type < 0 || type >= (int)array_size(tcpopt_protocols))
+		return 1;
+
+	desc = tcpopt_protocols[type];
 
 	for (i = 0; i < array_size(desc->templates); i++) {
 		if (desc->templates[i].token &&
 		    !strcmp(desc->templates[i].token, name)) {
+			if (block) {
+				block--;
+				continue;
+			}
+
 			if (val)
 				*val = i;
 			return 0;
@@ -587,7 +615,7 @@ static struct expr *json_parse_tcp_option_expr(struct json_ctx *ctx,
 
 	if (json_unpack(root, "{s:s}", "field", &field)) {
 		expr = tcpopt_expr_alloc(int_loc, descval,
-					 TCPOPTHDR_FIELD_KIND);
+					 TCPOPT_COMMON_KIND);
 		expr->exthdr.flags = NFT_EXTHDR_F_PRESENT;
 
 		return expr;