From 8fd7b7a153d25bae72a168d811462de9e779c1e1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jerry=20Lundstr=C3=B6m?= <lundstrom.jerry@gmail.com>
Date: Fri, 30 Jun 2023 09:21:48 +0200
Subject: [PATCH] EDNS parsing

- Only parse entire DNS message if EDNS indexers are used
---
 src/dns_message.c        | 4 ++--
 src/dns_protocol.c       | 4 ++++
 src/dns_protocol.h       | 2 ++
 src/edns_bufsiz_index.c  | 6 ++++++
 src/edns_bufsiz_index.h  | 1 +
 src/edns_version_index.c | 6 ++++++
 src/edns_version_index.h | 1 +
 7 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/dns_message.c b/src/dns_message.c
index a6e55da9..f13c8a8c 100644
--- a/src/dns_message.c
+++ b/src/dns_message.c
@@ -104,8 +104,8 @@ static indexer indexers[] = {
     { "certain_qnames", 0, certain_qnames_indexer, certain_qnames_iterator },
     { "query_classification", 0, query_classification_indexer, query_classification_iterator },
     { "idn_qname", 0, idn_qname_indexer, idn_qname_iterator },
-    { "edns_version", 0, edns_version_indexer, edns_version_iterator },
-    { "edns_bufsiz", 0, edns_bufsiz_indexer, edns_bufsiz_iterator },
+    { "edns_version", edns_version_init, edns_version_indexer, edns_version_iterator },
+    { "edns_bufsiz", edns_bufsiz_init, edns_bufsiz_indexer, edns_bufsiz_iterator },
     { "do_bit", 0, do_bit_indexer, do_bit_iterator },
     { "rd_bit", 0, rd_bit_indexer, rd_bit_iterator },
     { "tc_bit", 0, tc_bit_indexer, tc_bit_iterator },
diff --git a/src/dns_protocol.c b/src/dns_protocol.c
index e4498a67..2e72b766 100644
--- a/src/dns_protocol.c
+++ b/src/dns_protocol.c
@@ -255,6 +255,8 @@ static off_t skip_rr(const u_char* buf, int len, off_t offset)
     return offset;
 }
 
+int dns_protocol_parse_edns0 = 0;
+
 int dns_protocol_handler(const u_char* buf, int len, void* udata)
 {
     transport_message* tm = udata;
@@ -304,6 +306,8 @@ int dns_protocol_handler(const u_char* buf, int len, void* udata)
         offset = new_offset;
         qdcount--;
     }
+    if (!dns_protocol_parse_edns0)
+        goto handle_m;
     assert(offset <= len);
 
     /*
diff --git a/src/dns_protocol.h b/src/dns_protocol.h
index 689fed02..90b8f454 100644
--- a/src/dns_protocol.h
+++ b/src/dns_protocol.h
@@ -39,6 +39,8 @@
 
 #include <sys/types.h>
 
+extern int dns_protocol_parse_edns0;
+
 int dns_protocol_handler(const u_char* buf, int len, void* udata);
 
 #endif /* __dsc_dns_protocol_h */
diff --git a/src/edns_bufsiz_index.c b/src/edns_bufsiz_index.c
index 27f5d74e..3d67be76 100644
--- a/src/edns_bufsiz_index.c
+++ b/src/edns_bufsiz_index.c
@@ -37,6 +37,12 @@
 #include "config.h"
 
 #include "edns_bufsiz_index.h"
+#include "dns_protocol.h"
+
+void edns_bufsiz_init(void)
+{
+    dns_protocol_parse_edns0 = 1;
+}
 
 int edns_bufsiz_max = 0;
 
diff --git a/src/edns_bufsiz_index.h b/src/edns_bufsiz_index.h
index d1253485..c9961778 100644
--- a/src/edns_bufsiz_index.h
+++ b/src/edns_bufsiz_index.h
@@ -39,6 +39,7 @@
 
 #include "dns_message.h"
 
+void edns_bufsiz_init(void);
 int edns_bufsiz_indexer(const dns_message*);
 int edns_bufsiz_iterator(const char** label);
 
diff --git a/src/edns_version_index.c b/src/edns_version_index.c
index d7b6f380..587f5dca 100644
--- a/src/edns_version_index.c
+++ b/src/edns_version_index.c
@@ -37,6 +37,12 @@
 #include "config.h"
 
 #include "edns_version_index.h"
+#include "dns_protocol.h"
+
+void edns_version_init(void)
+{
+    dns_protocol_parse_edns0 = 1;
+}
 
 int edns_version_max = 0;
 
diff --git a/src/edns_version_index.h b/src/edns_version_index.h
index 444b622f..b30d3e08 100644
--- a/src/edns_version_index.h
+++ b/src/edns_version_index.h
@@ -39,6 +39,7 @@
 
 #include "dns_message.h"
 
+void edns_version_init(void);
 int edns_version_indexer(const dns_message*);
 int edns_version_iterator(const char** label);