From 305cb79c5754d5554729b18a2c06fe7ce699687a Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Thu, 18 Feb 2021 21:35:09 +0000
Subject: [PATCH] Simplify preceding fix.

Remove distinction between retry with same QID/SP and
retry for same query with different QID/SP. If the
QID/SP are the same as an existing one, simply retry,
if a new QID/SP is seen, add to the list to be replied to.
---
 src/forward.c | 64 ++++++++++++++++++++---------------------------------------
 1 file changed, 22 insertions(+), 42 deletions(-)

diff --git a/src/forward.c b/src/forward.c
index e82e14a..6bbf8a4 100644
--- a/src/forward.c
+++ b/src/forward.c
@@ -17,9 +17,6 @@
 #include "dnsmasq.h"
 
 static struct frec *lookup_frec(unsigned short id, int fd, int family, void *hash);
-static struct frec *lookup_frec_by_sender(unsigned short id,
-					  union mysockaddr *addr,
-					  void *hash);
 static struct frec *lookup_frec_by_query(void *hash, unsigned int flags);
 
 static unsigned short get_id(void);
@@ -278,18 +275,20 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
     fwd_flags |= FREC_DO_QUESTION;
 #endif
   
-  /* Check for retry on existing query from same source */
-  if (!forward && (!(forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, hash))))
+  /* Check for retry on existing query */
+  if (!forward && (forward = lookup_frec_by_query(hash, fwd_flags)))
     {
-      /* Maybe query from new source, but the same query may be in progress
-	 from another source. If so, just add this client to the
-	 list that will get the reply.*/
-	 
-      if (!option_bool(OPT_ADD_MAC) && !option_bool(OPT_MAC_B64) &&
-	  (forward = lookup_frec_by_query(hash, fwd_flags)))
-	{
-	  struct frec_src *new;
+      struct frec_src *src;
+
+      for (src = &forward->frec_src; src; src = src->next)
+	if (src->orig_id == ntohs(header->id) && 
+	    sockaddr_isequal(&src->source, udpaddr))
+	  break;
 
+      /* Existing query, but from new source, just add this 
+	 client to the list that will get the reply.*/
+      if (!src)
+	{
 	  /* Note whine_malloc() zeros memory. */
 	  if (!daemon->free_frec_src &&
 	      daemon->frec_src_count < daemon->ftabsize &&
@@ -303,16 +302,16 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
 	  if (!daemon->free_frec_src)
 	    return 0;
 	  
-	  new = daemon->free_frec_src;
-	  daemon->free_frec_src = new->next;
-	  new->next = forward->frec_src.next;
-	  forward->frec_src.next = new;
-	  new->orig_id = ntohs(header->id);
-	  new->source = *udpaddr;
-	  new->dest = *dst_addr;
-	  new->log_id = daemon->log_id;
-	  new->iface = dst_iface;
-	  new->fd = udpfd;
+	  src = daemon->free_frec_src;
+	  daemon->free_frec_src = src->next;
+	  src->next = forward->frec_src.next;
+	  forward->frec_src.next = src;
+	  src->orig_id = ntohs(header->id);
+	  src->source = *udpaddr;
+	  src->dest = *dst_addr;
+	  src->log_id = daemon->log_id;
+	  src->iface = dst_iface;
+	  src->fd = udpfd;
 	}
     }
 
@@ -2433,25 +2432,6 @@ static struct frec *lookup_frec(unsigned short id, int fd, int family, void *has
   return NULL;
 }
 
-static struct frec *lookup_frec_by_sender(unsigned short id,
-					  union mysockaddr *addr,
-					  void *hash)
-{
-  struct frec *f;
-  struct frec_src *src;
-
-  for (f = daemon->frec_list; f; f = f->next)
-    if (f->sentto &&
-	!(f->flags & (FREC_DNSKEY_QUERY | FREC_DS_QUERY)) &&
-	memcmp(hash, f->hash, HASH_SIZE) == 0)
-      for (src = &f->frec_src; src; src = src->next)
-	if (src->orig_id == id && 
-	    sockaddr_isequal(&src->source, addr))
-	  return f;
-  
-  return NULL;
-}
-
 static struct frec *lookup_frec_by_query(void *hash, unsigned int flags)
 {
   struct frec *f;
-- 
1.8.3.1