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, 36 insertions, 10 deletions

diff --git a/include/tcpopt.h b/include/tcpopt.h
index 7f3fbb8b..667c8a77 100644
--- a/include/tcpopt.h
+++ b/include/tcpopt.h
@@ -33,16 +33,42 @@ enum tcpopt_kind {
 	TCPOPT_KIND_SACK3 = 258,
 };
 
-enum tcpopt_hdr_fields {
-	TCPOPTHDR_FIELD_INVALID,
-	TCPOPTHDR_FIELD_KIND,
-	TCPOPTHDR_FIELD_LENGTH,
-	TCPOPTHDR_FIELD_SIZE,
-	TCPOPTHDR_FIELD_COUNT,
-	TCPOPTHDR_FIELD_LEFT,
-	TCPOPTHDR_FIELD_RIGHT,
-	TCPOPTHDR_FIELD_TSVAL,
-	TCPOPTHDR_FIELD_TSECR,
+/* Internal identifiers */
+enum tcpopt_common {
+	TCPOPT_COMMON_KIND,
+	TCPOPT_COMMON_LENGTH,
+};
+
+enum tcpopt_maxseg {
+	TCPOPT_MAXSEG_KIND,
+	TCPOPT_MAXSEG_LENGTH,
+	TCPOPT_MAXSEG_SIZE,
+};
+
+enum tcpopt_timestamp {
+	TCPOPT_TS_KIND,
+	TCPOPT_TS_LENGTH,
+	TCPOPT_TS_TSVAL,
+	TCPOPT_TS_TSECR,
+};
+
+enum tcpopt_windowscale {
+	TCPOPT_WINDOW_KIND,
+	TCPOPT_WINDOW_LENGTH,
+	TCPOPT_WINDOW_COUNT,
+};
+
+enum tcpopt_hdr_field_sack {
+	TCPOPT_SACK_KIND,
+	TCPOPT_SACK_LENGTH,
+	TCPOPT_SACK_LEFT,
+	TCPOPT_SACK_RIGHT,
+	TCPOPT_SACK_LEFT1,
+	TCPOPT_SACK_RIGHT1,
+	TCPOPT_SACK_LEFT2,
+	TCPOPT_SACK_RIGHT2,
+	TCPOPT_SACK_LEFT3,
+	TCPOPT_SACK_RIGHT3,
 };
 
 extern const struct exthdr_desc *tcpopt_protocols[__TCPOPT_KIND_MAX];