File dnsmasq-dnspooq.patch of Package dnsmasq.17856

--- bld/Android.mk.orig
+++ bld/Android.mk
@@ -10,7 +10,8 @@ LOCAL_SRC_FILES :=  bpf.c cache.c dbus.c
 		    dhcp6.c rfc3315.c dhcp-common.c outpacket.c \
 		    radv.c slaac.c auth.c ipset.c domain.c \
 	            dnssec.c dnssec-openssl.c blockdata.c tables.c \
-		    loop.c inotify.c poll.c rrfilter.c edns0.c arp.c
+		    loop.c inotify.c poll.c rrfilter.c edns0.c arp.c \
+		    hash_questions.c
 
 LOCAL_MODULE := dnsmasq
 
--- bld/pkg-wrapper.orig
+++ bld/pkg-wrapper
@@ -1,33 +1,37 @@
 #!/bin/sh
 
-search=$1
-shift
-pkg=$1
-shift
-op=$1
-shift
-
 in=`cat`
 
-if grep "^\#[[:space:]]*define[[:space:]]*$search" config.h >/dev/null 2>&1 || \
-    echo $in | grep $search >/dev/null 2>&1; then
-# Nasty, nasty, in --copy, arg 2 is another config to search for, use with NO_GMP
+search()
+{
+    grep "^\#[[:space:]]*define[[:space:]]*$1" config.h >/dev/null 2>&1 || \
+    echo $in | grep $1 >/dev/null 2>&1
+}
+
+while [ "$#" -gt 0 ]; do
+    search=$1
+    pkg=$2
+    op=$3
+    lib=$4
+    shift 4
+if search "$search"; then
+
+# Nasty, nasty, in --copy, arg 2 (if non-empty) is another config to search for, used with NO_GMP
     if [ $op = "--copy" ]; then
-	if grep "^\#[[:space:]]*define[[:space:]]*$pkg" config.h >/dev/null 2>&1 || \
-            echo $in | grep $pkg >/dev/null 2>&1; then
+	if [ -z "$pkg" ]; then
+	    pkg="$lib"
+	elif search "$pkg"; then
 	    pkg=""
 	else 
-	    pkg="$*"
+	    pkg="$lib"
 	fi
-    elif grep "^\#[[:space:]]*define[[:space:]]*${search}_STATIC" config.h >/dev/null 2>&1 || \
-	      echo $in | grep ${search}_STATIC >/dev/null 2>&1; then
-	pkg=`$pkg  --static $op $*`
+    elif search "${search}_STATIC"; then
+	pkg=`$pkg  --static $op $lib`
     else
-	pkg=`$pkg $op $*`
+	pkg=`$pkg $op $lib`
     fi
-
-    if grep "^\#[[:space:]]*define[[:space:]]*${search}_STATIC" config.h >/dev/null 2>&1 || \
-	echo $in | grep ${search}_STATIC >/dev/null 2>&1; then
+    
+    if search "${search}_STATIC"; then
 	if [ $op = "--libs" ] || [ $op = "--copy" ]; then
 	    echo "-Wl,-Bstatic $pkg -Wl,-Bdynamic"
 	else
@@ -38,3 +42,4 @@ if grep "^\#[[:space:]]*define[[:space:]
     fi
 fi
 
+done
--- Makefile.orig
+++ Makefile
@@ -61,8 +61,10 @@ ct_cflags =     `echo $(COPTS) | $(top)/
 ct_libs =       `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_CONNTRACK $(PKG_CONFIG) --libs libnetfilter_conntrack`
 lua_cflags =    `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_LUASCRIPT $(PKG_CONFIG) --cflags lua5.2` 
 lua_libs =      `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_LUASCRIPT $(PKG_CONFIG) --libs lua5.2` 
-nettle_cflags = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC $(PKG_CONFIG) --cflags nettle hogweed`
-nettle_libs =   `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC $(PKG_CONFIG) --libs nettle hogweed`
+nettle_cflags = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC     $(PKG_CONFIG) --cflags 'nettle hogweed' \
+                                                        HAVE_NETTLEHASH $(PKG_CONFIG) --cflags nettle`
+nettle_libs =   `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC     $(PKG_CONFIG) --libs 'nettle hogweed' \
+                                                        HAVE_NETTLEHASH $(PKG_CONFIG) --libs nettle`
 gmp_libs =      `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC NO_GMP --copy -lgmp`
 sunos_libs =    `if uname | grep SunOS >/dev/null 2>&1; then echo -lsocket -lnsl -lposix4; fi`
 version =     -DVERSION='\"`$(top)/bld/get-version $(top)`\"'
@@ -76,7 +78,7 @@ objs = cache.o rfc1035.o util.o option.o
        helper.o tftp.o log.o conntrack.o dhcp6.o rfc3315.o \
        dhcp-common.o outpacket.o radv.o slaac.o auth.o ipset.o \
        domain.o dnssec.o blockdata.o tables.o loop.o inotify.o \
-       poll.o rrfilter.o edns0.o arp.o
+       poll.o rrfilter.o edns0.o arp.o hash_questions.o
 
 hdrs = dnsmasq.h config.h dhcp-protocol.h dhcp6-protocol.h \
        dns-protocol.h radv-protocol.h ip6addr.h
--- src/config.h.orig
+++ src/config.h
@@ -113,6 +113,9 @@ HAVE_AUTH
    define this to include the facility to act as an authoritative DNS
    server for one or more zones.
 
+HAVE_NETTLEHASH
+   include just hash function from nettle, but no DNSSEC.
+
 HAVE_DNSSEC
    include DNSSEC validator.
 
@@ -179,6 +182,7 @@ RESOLVFILE
 /* #define HAVE_IDN */
 /* #define HAVE_LIBIDN2 */
 /* #define HAVE_CONNTRACK */
+/* #define HAVE_NETTLEHASH */
 /* #define HAVE_DNSSEC */
 
 
@@ -439,6 +443,10 @@ static char *compile_opts =
 "no-"
 #endif
 "auth "
+#if !defined(HAVE_NETTLEHASH) && !defined(HAVE_DNSSEC)
+"no-"
+#endif
+"nettlehash "
 #ifndef HAVE_DNSSEC
 "no-"
 #endif
--- src/dnsmasq.h.orig
+++ src/dnsmasq.h
@@ -143,6 +143,10 @@ extern int capget(cap_user_header_t head
 #include <priv.h>
 #endif
 
+#if defined(HAVE_DNSSEC) || defined(HAVE_NETTLEHASH)
+#  include <nettle/nettle-meta.h>
+#endif
+
 /* daemon is function in the C library.... */
 #define daemon dnsmasq_daemon
 
@@ -607,25 +611,26 @@ struct hostsfile {
 #define FREC_DO_QUESTION       64
 #define FREC_ADDED_PHEADER    128
 #define FREC_TEST_PKTSZ       256
-#define FREC_HAS_EXTRADATA    512        
+#define FREC_HAS_EXTRADATA    512
+#define FREC_HAS_PHEADER     1024
 
-#ifdef HAVE_DNSSEC
-#define HASH_SIZE 20 /* SHA-1 digest size */
-#else
-#define HASH_SIZE sizeof(int)
-#endif
+#define HASH_SIZE 32 /* SHA-256 digest size */
 
 struct frec {
-  union mysockaddr source;
-  struct all_addr dest;
+  struct frec_src {
+    union mysockaddr source;
+    struct all_addr dest;
+    unsigned int iface, log_id;
+    unsigned short orig_id;
+    struct frec_src *next;
+  } frec_src;
   struct server *sentto; /* NULL means free */
   struct randfd *rfd4;
 #ifdef HAVE_IPV6
   struct randfd *rfd6;
 #endif
-  unsigned int iface;
-  unsigned short orig_id, new_id;
-  int log_id, fd, forwardall, flags;
+  unsigned short new_id;
+  int fd, forwardall, flags;
   time_t time;
   unsigned char *hash[HASH_SIZE];
 #ifdef HAVE_DNSSEC 
@@ -1029,6 +1034,8 @@ extern struct daemon {
 #endif
   unsigned int local_answer, queries_forwarded, auth_answer;
   struct frec *frec_list;
+  struct frec_src *free_frec_src;
+  int frec_src_count;
   struct serverfd *sfds;
   struct irec *interfaces;
   struct listener *listeners;
@@ -1148,7 +1155,6 @@ int check_for_bogus_wildcard(struct dns_
 			     struct bogus_addr *baddr, time_t now);
 int check_for_ignored_address(struct dns_header *header, size_t qlen, struct bogus_addr *baddr);
 int check_for_local_domain(char *name, time_t now);
-unsigned int questions_crc(struct dns_header *header, size_t plen, char *name);
 size_t resize_packet(struct dns_header *header, size_t plen, 
 		  unsigned char *pheader, size_t hlen);
 int add_resource_record(struct dns_header *header, char *limit, int *truncp,
@@ -1178,6 +1184,8 @@ int dnskey_keytag(int alg, int flags, un
 size_t filter_rrsigs(struct dns_header *header, size_t plen);
 unsigned char* hash_questions(struct dns_header *header, size_t plen, char *name);
 int setup_timestamp(void);
+const struct nettle_hash *hash_find(char *name);
+int hash_init(const struct nettle_hash *hash, void **ctxp, unsigned char **digestp);
 
 /* util.c */
 void rand_init(void);
--- src/dnssec.c.orig
+++ src/dnssec.c
@@ -82,7 +82,7 @@ static char *nsec3_digest_name(int diges
 }
  
 /* Find pointer to correct hash function in nettle library */
-static const struct nettle_hash *hash_find(char *name)
+const struct nettle_hash *hash_find(char *name)
 {
   int i;
   
@@ -99,7 +99,7 @@ static const struct nettle_hash *hash_fi
 }
 
 /* expand ctx and digest memory allocations if necessary and init hash function */
-static int hash_init(const struct nettle_hash *hash, void **ctxp, unsigned char **digestp)
+int hash_init(const struct nettle_hash *hash, void **ctxp, unsigned char **digestp)
 {
   static void *ctx = NULL;
   static unsigned char *digest = NULL;
@@ -543,133 +543,151 @@ static int check_date_range(u32 date_sta
     && serial_compare_32(curtime, date_end) == SERIAL_LT;
 }
 
-/* Return bytes of canonicalised rdata, when the return value is zero, the remaining 
-   data, pointed to by *p, should be used raw. */
-static int get_rdata(struct dns_header *header, size_t plen, unsigned char *end, char *buff, int bufflen,
-		     unsigned char **p, u16 **desc)
-{
-  int d = **desc;
-  
-  /* No more data needs mangling */
-  if (d == (u16)-1)
-    {
-      /* If there's more data than we have space for, just return what fits,
-	 we'll get called again for more chunks */
-      if (end - *p > bufflen)
-	{
-	  memcpy(buff, *p, bufflen);
-	  *p += bufflen;
-	  return bufflen;
-	}
-      
-      return 0;
+/* Return bytes of canonicalised rrdata one by one.
+   Init state->ip with the RR, and state->end with the end of same.
+   Init state->op to NULL.
+   Init state->desc to RR descriptor.
+   Init state->buff with a MAXDNAME * 2 buffer.
+   
+   After each call which returns 1, state->op points to the next byte of data.
+   On returning 0, the end has been reached.
+*/
+struct rdata_state {
+  u16 *desc;
+  size_t c;
+  unsigned char *end, *ip, *op;
+  char *buff;
+};
+
+static int get_rdata(struct dns_header *header, size_t plen, struct rdata_state *state)
+{
+  int d;
+  
+  if (state->op && state->c != 1)
+    {
+      state->op++;
+      state->c--;
+      return 1;
     }
- 
-  (*desc)++;
   
-  if (d == 0 && extract_name(header, plen, p, buff, 1, 0))
-    /* domain-name, canonicalise */
-    return to_wire(buff);
-  else
-    { 
-      /* plain data preceding a domain-name, don't run off the end of the data */
-      if ((end - *p) < d)
-	d = end - *p;
+  while (1)
+    {
+      d = *(state->desc);
       
-      if (d != 0)
+      if (d == (u16)-1)
 	{
-	  memcpy(buff, *p, d);
-	  *p += d;
+	  /* all the bytes to the end. */
+	  if ((state->c = state->end - state->ip) != 0)
+	    {
+	      state->op = state->ip;
+	      state->ip = state->end;;
+	    }
+	  else
+	    return 0;
 	}
-      
-      return d;
+      else
+	{
+	  state->desc++;
+	  
+	  if (d == (u16)0)
+	    {
+	      /* domain-name, canonicalise */
+	      int len;
+	      
+	      if (!extract_name(header, plen, &state->ip, state->buff, 1, 0) ||
+		  (len = to_wire(state->buff)) == 0)
+		continue;
+	      
+	      state->c = len;
+	      state->op = (unsigned char *)state->buff;
+	    }
+	  else
+	    {
+	      /* plain data preceding a domain-name, don't run off the end of the data */
+	      if ((state->end - state->ip) < d)
+		d = state->end - state->ip;
+	      
+	      if (d == 0)
+		continue;
+	      
+	      state->op = state->ip;
+	      state->c = d;
+	      state->ip += d;
+	    }
+	}  
+      return 1;
     }
 }
 
-/* Bubble sort the RRset into the canonical order. 
-   Note that the byte-streams from two RRs may get unsynced: consider 
-   RRs which have two domain-names at the start and then other data.
-   The domain-names may have different lengths in each RR, but sort equal
+/* Bubble sort the RRset into the canonical order. */
 
-   ------------
-   |abcde|fghi|
-   ------------
-   |abcd|efghi|
-   ------------
-
-   leaving the following bytes as deciding the order. Hence the nasty left1 and left2 variables.
-*/
-
-static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int rrsetidx, 
-		       unsigned char **rrset, char *buff1, char *buff2)
+static int sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int rrsetidx, 
+                      unsigned char **rrset, char *buff1, char *buff2)
 {
-  int swap, quit, i;
+  int swap, i, j;
   
   do
     {
       for (swap = 0, i = 0; i < rrsetidx-1; i++)
-	{
-	  int rdlen1, rdlen2, left1, left2, len1, len2, len, rc;
-	  u16 *dp1, *dp2;
-	  unsigned char *end1, *end2;
-	  /* Note that these have been determined to be OK previously,
-	     so we don't need to check for NULL return here. */
-	  unsigned char *p1 = skip_name(rrset[i], header, plen, 10);
-	  unsigned char *p2 = skip_name(rrset[i+1], header, plen, 10);
-	  
-	  p1 += 8; /* skip class, type, ttl */
-	  GETSHORT(rdlen1, p1);
-	  end1 = p1 + rdlen1;
-	  
-	  p2 += 8; /* skip class, type, ttl */
-	  GETSHORT(rdlen2, p2);
-	  end2 = p2 + rdlen2; 
-	  
-	  dp1 = dp2 = rr_desc;
-	  
-	  for (quit = 0, left1 = 0, left2 = 0, len1 = 0, len2 = 0; !quit;)
-	    {
-	      if (left1 != 0)
-		memmove(buff1, buff1 + len1 - left1, left1);
-	      
-	      if ((len1 = get_rdata(header, plen, end1, buff1 + left1, (MAXDNAME * 2) - left1, &p1, &dp1)) == 0)
-		{
-		  quit = 1;
-		  len1 = end1 - p1;
-		  memcpy(buff1 + left1, p1, len1);
-		}
-	      len1 += left1;
-	      
-	      if (left2 != 0)
-		memmove(buff2, buff2 + len2 - left2, left2);
-	      
-	      if ((len2 = get_rdata(header, plen, end2, buff2 + left2, (MAXDNAME *2) - left2, &p2, &dp2)) == 0)
-		{
-		  quit = 1;
-		  len2 = end2 - p2;
-		  memcpy(buff2 + left2, p2, len2);
-		}
-	      len2 += left2;
-	       
-	      if (len1 > len2)
-		left1 = len1 - len2, left2 = 0, len = len2;
-	      else
-		left2 = len2 - len1, left1 = 0, len = len1;
-	      
-	      rc = (len == 0) ? 0 : memcmp(buff1, buff2, len);
+        {
+          int rdlen1, rdlen2;
+          struct rdata_state state1, state2;
+          
+          /* Note that these have been determined to be OK previously,
+             so we don't need to check for NULL return here. */
+          state1.ip = skip_name(rrset[i], header, plen, 10);
+          state2.ip = skip_name(rrset[i+1], header, plen, 10);
+          state1.op = state2.op = NULL;
+          state1.buff = buff1;
+          state2.buff = buff2;
+          state1.desc = state2.desc = rr_desc;
+          
+          state1.ip += 8; /* skip class, type, ttl */
+          GETSHORT(rdlen1, state1.ip);
+          if (!CHECK_LEN(header, state1.ip, plen, rdlen1))
+            return rrsetidx; /* short packet */
+          state1.end = state1.ip + rdlen1;
+          
+          state2.ip += 8; /* skip class, type, ttl */
+          GETSHORT(rdlen2, state2.ip);
+          if (!CHECK_LEN(header, state2.ip, plen, rdlen2))
+            return rrsetidx; /* short packet */
+          state2.end = state2.ip + rdlen2; 
+	  
+          while (1)
+            {
+              int ok1, ok2;
+              
+              ok1 = get_rdata(header, plen, &state1);
+              ok2 = get_rdata(header, plen, &state2);
 	      
-	      if (rc > 0 || (rc == 0 && quit && len1 > len2))
-		{
-		  unsigned char *tmp = rrset[i+1];
-		  rrset[i+1] = rrset[i];
-		  rrset[i] = tmp;
-		  swap = quit = 1;
-		}
-	      else if (rc < 0)
-		quit = 1;
-	    }
-	}
+              if (!ok1 && !ok2)
+                {
+                  /* Two RRs are equal, remove one copy. RFC 4034, para 6.3 */
+                  for (j = i+1; j < rrsetidx-1; j++)
+                    rrset[j] = rrset[j+1];
+                  rrsetidx--;
+                  i--;
+                  break;
+                }
+              else if (ok1 && (!ok2 || *state1.op > *state2.op)) 
+                {
+                  unsigned char *tmp = rrset[i+1];
+                  rrset[i+1] = rrset[i];
+                  rrset[i] = tmp;
+                  swap = 1;
+                  break;
+                }
+              else if (ok2 && (!ok1 || *state2.op > *state1.op))
+                break;
+              
+              /* arrive here when bytes are equal, go round the loop again
+                 and compare the next ones. */
+            }
+        }
     } while (swap);
+  
+  return rrsetidx;
 }
 
 static unsigned char **rrset = NULL, **sigs = NULL;
@@ -860,12 +878,15 @@ static int validate_rrset(time_t now, st
       wire_len = to_wire(keyname);
       hash->update(ctx, (unsigned int)wire_len, (unsigned char*)keyname);
       from_wire(keyname);
+
+#define RRBUFLEN 300 /* Most RRs are smaller than this. */
       
       for (i = 0; i < rrsetidx; ++i)
 	{
-	  int seg;
-	  unsigned char *end, *cp;
-	  u16 len, *dp;
+	  int j;
+	  struct rdata_state state;
+	  u16 len;
+	  unsigned char rrbuf[RRBUFLEN];
 	  
 	  p = rrset[i];
 	  if (!extract_name(header, plen, &p, name, 1, 10)) 
@@ -876,12 +897,11 @@ static int validate_rrset(time_t now, st
 	  /* if more labels than in RRsig name, hash *.<no labels in rrsig labels field>  4035 5.3.2 */
 	  if (labels < name_labels)
 	    {
-	      int k;
-	      for (k = name_labels - labels; k != 0; k--)
+	      for (j = name_labels - labels; j != 0; j--)
 		{
 		  while (*name_start != '.' && *name_start != 0)
 		    name_start++;
-		  if (k != 1 && *name_start == '.')
+		  if (j != 1 && *name_start == '.')
 		    name_start++;
 		}
 	      
@@ -902,24 +922,44 @@ static int validate_rrset(time_t now, st
 	  if (!CHECK_LEN(header, p, plen, rdlen))
 	    return STAT_BOGUS; 
 	  
-	  end = p + rdlen;
-	  
-	  /* canonicalise rdata and calculate length of same, use name buffer as workspace.
-	     Note that name buffer is twice MAXDNAME long in DNSSEC mode. */
-	  cp = p;
-	  dp = rr_desc;
-	  for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)) != 0; len += seg);
-	  len += end - cp;
-	  len = htons(len);
+	  /* canonicalise rdata and calculate length of same, use 
+	     name buffer as workspace for get_rdata. */
+	  state.ip = p;
+	  state.op = NULL;
+	  state.desc = rr_desc;
+	  state.buff = name;
+	  state.end = p + rdlen;
+	  
+	  for (j = 0; get_rdata(header, plen, &state); j++)
+	    if (j < RRBUFLEN)
+	      rrbuf[j] = *state.op;
+
+	  len = htons((u16)j);
 	  hash->update(ctx, 2, (unsigned char *)&len); 
+
+	  /* If the RR is shorter than RRBUFLEN (most of them, in practice)
+	     then we can just digest it now. If it exceeds RRBUFLEN we have to
+	     go back to the start and do it in chunks. */
+	  if (j >= RRBUFLEN)
+	    {
+	      state.ip = p;
+	      state.op = NULL;
+	      state.desc = rr_desc;
+
+	      for (j = 0; get_rdata(header, plen, &state); j++)
+		{
+		   rrbuf[j] = *state.op;
+
+		   if (j == RRBUFLEN - 1)
+		     {
+		       hash->update(ctx, RRBUFLEN, rrbuf);
+		       j = -1;
+		     }
+		}
+	    }
 	  
-	  /* Now canonicalise again and digest. */
-	  cp = p;
-	  dp = rr_desc;
-	  while ((seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)))
-	    hash->update(ctx, seg, (unsigned char *)name);
-	  if (cp != end)
-	    hash->update(ctx, end - cp, cp);
+	  if (j != 0)
+	    hash->update(ctx, j, rrbuf);
 	}
      
       hash->digest(ctx, hash->digest_size, digest);
@@ -2332,35 +2372,4 @@ size_t dnssec_generate_query(struct dns_
   return ret;
 }
 
-unsigned char* hash_questions(struct dns_header *header, size_t plen, char *name)
-{
-  int q;
-  unsigned int len;
-  unsigned char *p = (unsigned char *)(header+1);
-  const struct nettle_hash *hash;
-  void *ctx;
-  unsigned char *digest;
-  
-  if (!(hash = hash_find("sha1")) || !hash_init(hash, &ctx, &digest))
-    return NULL;
-  
-  for (q = ntohs(header->qdcount); q != 0; q--) 
-    {
-      if (!extract_name(header, plen, &p, name, 1, 4))
-	break; /* bad packet */
-      
-      len = to_wire(name);
-      hash->update(ctx, len, (unsigned char *)name);
-      /* CRC the class and type as well */
-      hash->update(ctx, 4, p);
-
-      p += 4;
-      if (!CHECK_LEN(header, p, plen, 0))
-	break; /* bad packet */
-    }
-  
-  hash->digest(ctx, hash->digest_size, digest);
-  return digest;
-}
-
 #endif /* HAVE_DNSSEC */
--- src/forward.c.orig
+++ src/forward.c
@@ -16,10 +16,12 @@
 
 #include "dnsmasq.h"
 
-static struct frec *lookup_frec(unsigned short id, void *hash);
+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);
 static void free_frec(struct frec *f);
 
@@ -237,21 +239,30 @@ static int forward_query(int udpfd, unio
   char *domain = NULL;
   int type = SERV_DO_DNSSEC, norebind = 0;
   struct all_addr *addrp = NULL;
+  unsigned int fwd_flags = 0;
   unsigned int flags = 0;
   struct server *start = NULL;
-#ifdef HAVE_DNSSEC
   void *hash = hash_questions(header, plen, daemon->namebuff);
+#ifdef HAVE_DNSSEC
   int do_dnssec = 0;
-#else
-  unsigned int crc = questions_crc(header, plen, daemon->namebuff);
-  void *hash = &crc;
 #endif
  unsigned int gotname = extract_request(header, plen, daemon->namebuff, NULL);
-
+ unsigned char *oph = find_pseudoheader(header, plen, NULL, NULL, NULL, NULL);
  (void)do_bit;
 
+  if (header->hb4 & HB4_CD)
+    fwd_flags |= FREC_CHECKING_DISABLED;
+  if (ad_reqd)
+    fwd_flags |= FREC_AD_QUESTION;
+  if (oph)
+    fwd_flags |= FREC_HAS_PHEADER;
+#ifdef HAVE_DNSSEC
+  if (do_bit)
+    fwd_flags |= FREC_DO_QUESTION;
+#endif
+  
   /* may be no servers available. */
-  if (forward || (hash && (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, hash))))
+  if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, hash)))
     {
       /* If we didn't get an answer advertising a maximal packet in EDNS,
 	 fall back to 1280, which should work everywhere on IPv6.
@@ -326,6 +337,42 @@ static int forward_query(int udpfd, unio
     }
   else 
     {
+      /* 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.
+	 
+	 Note that is the EDNS client subnet option is in use, we can't do this,
+	 as the clients (and therefore query EDNS options) will be different
+	 for each query. The EDNS subnet code has checks to avoid
+	 attacks in this case. */
+      if (!option_bool(OPT_CLIENT_SUBNET) && (forward = lookup_frec_by_query(hash, fwd_flags)))
+	{
+	  /* Note whine_malloc() zeros memory. */
+	  if (!daemon->free_frec_src &&
+	      daemon->frec_src_count < daemon->ftabsize &&
+	      (daemon->free_frec_src = whine_malloc(sizeof(struct frec_src))))
+	    {
+	      daemon->frec_src_count++;
+	      daemon->free_frec_src->next = NULL;
+	    }
+	  
+	  /* If we've been spammed with many duplicates, just drop the query. */
+	  if (daemon->free_frec_src)
+	    {
+	      struct frec_src *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;
+	    }
+	  
+	  return 1;
+	}
+	
       if (gotname)
 	flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain, &norebind);
       
@@ -340,15 +387,16 @@ static int forward_query(int udpfd, unio
       
       if (forward)
 	{
-	  forward->source = *udpaddr;
-	  forward->dest = *dst_addr;
-	  forward->iface = dst_iface;
-	  forward->orig_id = ntohs(header->id);
+	  forward->frec_src.source = *udpaddr;
+	  forward->frec_src.orig_id = ntohs(header->id);
+	  forward->frec_src.dest = *dst_addr;
+	  forward->frec_src.iface = dst_iface;
+	  forward->frec_src.next = NULL;
 	  forward->new_id = get_id();
 	  forward->fd = udpfd;
 	  memcpy(forward->hash, hash, HASH_SIZE);
 	  forward->forwardall = 0;
-	  forward->flags = 0;
+	  forward->flags = fwd_flags;
 	  if (norebind)
 	    forward->flags |= FREC_NOREBIND;
 	  if (header->hb4 & HB4_CD)
@@ -402,18 +450,12 @@ static int forward_query(int udpfd, unio
       size_t edns0_len;
 
       /* If a query is retried, use the log_id for the retry when logging the answer. */
-      forward->log_id = daemon->log_id;
+      forward->frec_src.log_id = daemon->log_id;
       
-      edns0_len  = add_edns0_config(header, plen, ((unsigned char *)header) + PACKETSZ, &forward->source, now, &subnet);
+      plen  = add_edns0_config(header, plen, ((unsigned char *)header) + PACKETSZ, &forward->frec_src.source, now, &subnet);
       
-      if (edns0_len != plen)
-	{
-	  plen = edns0_len;
-	  forward->flags |= FREC_ADDED_PHEADER;
-	  
-	  if (subnet)
-	    forward->flags |= FREC_HAS_SUBNET;
-	}
+      if (subnet)
+	forward->flags |= FREC_HAS_SUBNET;
       
 #ifdef HAVE_DNSSEC
       if (option_bool(OPT_DNSSEC_VALID) && do_dnssec)
@@ -478,7 +520,7 @@ static int forward_query(int udpfd, unio
 		  if (option_bool(OPT_CONNTRACK))
 		    {
 		      unsigned int mark;
-		      if (get_incoming_mark(&forward->source, &forward->dest, 0, &mark))
+		      if (get_incoming_mark(&forward->frec_src.source, &forward->frec_src.dest, 0, &mark))
 			setsockopt(fd, SOL_SOCKET, SO_MARK, &mark, sizeof(unsigned int));
 		    }
 #endif
@@ -541,7 +583,7 @@ static int forward_query(int udpfd, unio
 	return 1;
       
       /* could not send on, prepare to return */ 
-      header->id = htons(forward->orig_id);
+      header->id = htons(forward->frec_src.orig_id);
       free_frec(forward); /* cancel */
     }	  
   
@@ -740,9 +782,6 @@ void reply_query(int fd, int family, tim
   size_t nn;
   struct server *server;
   void *hash;
-#ifndef HAVE_DNSSEC
-  unsigned int crc;
-#endif
 
   /* packet buffer overwritten */
   daemon->srv_save = NULL;
@@ -768,20 +807,15 @@ void reply_query(int fd, int family, tim
   if (!server)
     return;
   
-#ifdef HAVE_DNSSEC
   hash = hash_questions(header, n, daemon->namebuff);
-#else
-  hash = &crc;
-  crc = questions_crc(header, n, daemon->namebuff);
-#endif
   
-  if (!(forward = lookup_frec(ntohs(header->id), hash)))
+  if (!(forward = lookup_frec(ntohs(header->id), fd, family, hash)))
     return;
   
   /* log_query gets called indirectly all over the place, so 
      pass these in global variables - sorry. */
-  daemon->log_display_id = forward->log_id;
-  daemon->log_source_addr = &forward->source;
+  daemon->log_display_id = forward->frec_src.log_id;
+  daemon->log_source_addr = &forward->frec_src.source;
   
   if (daemon->ignore_addr && RCODE(header) == NOERROR &&
       check_for_ignored_address(header, n, daemon->ignore_addr))
@@ -967,6 +1001,7 @@ void reply_query(int fd, int family, tim
 #ifdef HAVE_IPV6
 		      new->rfd6 = NULL;
 #endif
+		      new->frec_src.next = NULL;
 		      new->flags &= ~(FREC_DNSKEY_QUERY | FREC_DS_QUERY);
 		      
 		      new->dependent = forward; /* to find query awaiting new one. */
@@ -984,9 +1019,7 @@ void reply_query(int fd, int family, tim
 			  nn = dnssec_generate_query(header,((unsigned char *) header) + server->edns_pktsz,
 						     daemon->keyname, forward->class, T_DS, &server->addr, server->edns_pktsz);
 			}
-		      if ((hash = hash_questions(header, nn, daemon->namebuff)))
-			memcpy(new->hash, hash, HASH_SIZE);
-		      new->new_id = get_id();
+		      memcpy(new->hash, hash_questions(header, nn, daemon->namebuff), HASH_SIZE);
 		      header->id = htons(new->new_id);
 		      /* Save query for retransmission */
 		      new->stash = blockdata_alloc((char *)header, nn);
@@ -1021,7 +1054,7 @@ void reply_query(int fd, int family, tim
 			  if (option_bool(OPT_CONNTRACK))
 			    {
 			      unsigned int mark;
-			      if (get_incoming_mark(&orig->source, &orig->dest, 0, &mark))
+			      if (get_incoming_mark(&orig->frec_src.source, &orig->frec_src.dest, 0, &mark))
 				setsockopt(fd, SOL_SOCKET, SO_MARK, &mark, sizeof(unsigned int));
 			    }
 #endif
@@ -1089,9 +1122,11 @@ void reply_query(int fd, int family, tim
       
       if ((nn = process_reply(header, now, forward->sentto, (size_t)n, check_rebind, no_cache_dnssec, cache_secure, bogusanswer, 
 			      forward->flags & FREC_AD_QUESTION, forward->flags & FREC_DO_QUESTION, 
-			      forward->flags & FREC_ADDED_PHEADER, forward->flags & FREC_HAS_SUBNET, &forward->source)))
+			      forward->flags & FREC_ADDED_PHEADER, forward->flags & FREC_HAS_SUBNET, &forward->frec_src.source)))
 	{
-	  header->id = htons(forward->orig_id);
+	  struct frec_src *src;
+
+	  header->id = htons(forward->frec_src.orig_id);
 	  header->hb4 |= HB4_RA; /* recursion if available */
 #ifdef HAVE_DNSSEC
 	  /* We added an EDNSO header for the purpose of getting DNSSEC RRs, and set the value of the UDP payload size
@@ -1106,8 +1141,22 @@ void reply_query(int fd, int family, tim
 	      nn = resize_packet(header, nn, NULL, 0);
 	    }
 #endif
+	  for (src = &forward->frec_src; src; src = src->next)
+	    {
+	      header->id = htons(src->orig_id);
+
+	      send_from(forward->fd, option_bool(OPT_NOWILD) || option_bool (OPT_CLEVERBIND), daemon->packet, nn, 
+			&src->source, &src->dest, src->iface);
+
+	      if (option_bool(OPT_EXTRALOG) && src != &forward->frec_src)
+		{
+		  daemon->log_display_id = src->log_id;
+		  daemon->log_source_addr = &src->source;
+		  log_query(F_UPSTREAM, "query", NULL, "duplicate");
+		}
+	    }
 	  send_from(forward->fd, option_bool(OPT_NOWILD) || option_bool (OPT_CLEVERBIND), daemon->packet, nn, 
-		    &forward->source, &forward->dest, forward->iface);
+		    &forward->frec_src.source, &forward->frec_src.dest, forward->frec_src.iface);
 	}
       free_frec(forward); /* cancel */
     }
@@ -1804,15 +1853,9 @@ unsigned char *tcp_request(int confd, ti
 	      if (!flags && last_server)
 		{
 		  struct server *firstsendto = NULL;
-#ifdef HAVE_DNSSEC
-		  unsigned char *newhash, hash[HASH_SIZE];
-		  if ((newhash = hash_questions(header, (unsigned int)size, daemon->namebuff)))
-		    memcpy(hash, newhash, HASH_SIZE);
-		  else
-		    memset(hash, 0, HASH_SIZE);
-#else
-		  unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff);
-#endif		  
+		  unsigned char hash[HASH_SIZE];
+		  memcpy(hash, hash_questions(header, (unsigned int)size, daemon->namebuff), HASH_SIZE);
+
 		  /* Loop round available servers until we succeed in connecting to one.
 		     Note that this code subtly ensures that consecutive queries on this connection
 		     which can go to the same server, do so. */
@@ -1955,20 +1998,11 @@ unsigned char *tcp_request(int confd, ti
 		      /* If the crc of the question section doesn't match the crc we sent, then
 			 someone might be attempting to insert bogus values into the cache by 
 			 sending replies containing questions and bogus answers. */
-#ifdef HAVE_DNSSEC
-		      newhash = hash_questions(header, (unsigned int)m, daemon->namebuff);
-		      if (!newhash || memcmp(hash, newhash, HASH_SIZE) != 0)
+		      if (memcmp(hash, hash_questions(header, (unsigned int)m, daemon->namebuff), HASH_SIZE) != 0)
 			{ 
 			  m = 0;
 			  break;
 			}
-#else			  
-		      if (crc != questions_crc(header, (unsigned int)m, daemon->namebuff))
-			{
-			  m = 0;
-			  break;
-			}
-#endif
 
 		      m = process_reply(header, now, last_server, (unsigned int)m, 
 					option_bool(OPT_NO_REBIND) && !norebind, no_cache_dnssec, cache_secure, bogusanswer,
@@ -2062,6 +2096,17 @@ void free_rfd(struct randfd *rfd)
 
 static void free_frec(struct frec *f)
 {
+  struct frec_src *last;
+  
+  /* add back to freelist if not the record builtin to every frec. */
+  for (last = f->frec_src.next; last && last->next; last = last->next) ;
+  if (last)
+    {
+      last->next = daemon->free_frec_src;
+      daemon->free_frec_src = f->frec_src.next;
+    }
+    
+  f->frec_src.next = NULL;    
   free_rfd(f->rfd4);
   f->rfd4 = NULL;
   f->sentto = NULL;
@@ -2177,14 +2222,25 @@ struct frec *get_new_frec(time_t now, in
 }
 
 /* crc is all-ones if not known. */
-static struct frec *lookup_frec(unsigned short id, void *hash)
+static struct frec *lookup_frec(unsigned short id, int fd, int family, void *hash)
 {
   struct frec *f;
 
   for(f = daemon->frec_list; f; f = f->next)
     if (f->sentto && f->new_id == id && 
-	(!hash || memcmp(hash, f->hash, HASH_SIZE) == 0))
-      return f;
+	(memcmp(hash, f->hash, HASH_SIZE) == 0))
+      {
+	/* sent from random port */
+	if (family == AF_INET && f->rfd4 && f->rfd4->fd == fd)
+	  return f;
+
+	if (family == AF_INET6 && f->rfd6 && f->rfd6->fd == fd)
+	  return f;
+
+	/* sent to upstream from bound socket. */
+	if (f->sentto->sfd && f->sentto->sfd->fd == fd)
+	  return f;
+      }
       
   return NULL;
 }
@@ -2194,17 +2250,39 @@ static struct frec *lookup_frec_by_sende
 					  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;
+
+  /* FREC_DNSKEY and FREC_DS_QUERY are never set in flags, so the test below 
+     ensures that no frec created for internal DNSSEC query can be returned here. */
+
+#define FLAGMASK (FREC_CHECKING_DISABLED | FREC_AD_QUESTION | FREC_DO_QUESTION \
+		  | FREC_HAS_PHEADER | FREC_DNSKEY_QUERY | FREC_DS_QUERY)
   
   for(f = daemon->frec_list; f; f = f->next)
     if (f->sentto &&
-	f->orig_id == id && 
-	memcmp(hash, f->hash, HASH_SIZE) == 0 &&
-	sockaddr_isequal(&f->source, addr))
+	(f->flags & FLAGMASK) == flags &&
+	memcmp(hash, f->hash, HASH_SIZE) == 0)
       return f;
-   
+  
   return NULL;
 }
- 
+
 /* Send query packet again, if we can. */
 void resend_query()
 {
@@ -2245,12 +2323,20 @@ void server_gone(struct server *server)
 static unsigned short get_id(void)
 {
   unsigned short ret = 0;
+  struct frec *f;
   
-  do 
-    ret = rand16();
-  while (lookup_frec(ret, NULL));
-  
-  return ret;
+  while (1)
+    {
+      ret = rand16();
+
+      /* ensure id is unique. */
+      for (f = daemon->frec_list; f; f = f->next)
+	if (f->sentto && f->new_id == ret)
+	  break;
+
+      if (!f)
+	return ret;
+    }
 }
 
 
--- /dev/null
+++ src/hash_questions.c
@@ -0,0 +1,281 @@
+/* Copyright (c) 2012-2020 Simon Kelley
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 dated June, 1991, or
+   (at your option) version 3 dated 29 June, 2007.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+
+/* Hash the question section. This is used to safely detect query 
+   retransmission and to detect answers to questions we didn't ask, which 
+   might be poisoning attacks. Note that we decode the name rather 
+   than CRC the raw bytes, since replies might be compressed differently. 
+   We ignore case in the names for the same reason. 
+
+   The hash used is SHA-256. If we're building with DNSSEC support,
+   we use the Nettle cypto library. If not, we prefer not to
+   add a dependency on Nettle, and use a stand-alone implementaion. 
+*/
+
+#include "dnsmasq.h"
+
+#if defined(HAVE_DNSSEC) || defined(HAVE_NETTLEHASH)
+unsigned char *hash_questions(struct dns_header *header, size_t plen, char *name)
+{
+  int q;
+  unsigned char *p = (unsigned char *)(header+1);
+  const struct nettle_hash *hash;
+  void *ctx;
+  unsigned char *digest;
+  
+  if (!(hash = hash_find("sha256")) || !hash_init(hash, &ctx, &digest))
+    {
+      /* don't think this can ever happen. */
+      static unsigned char dummy[HASH_SIZE];
+      static int warned = 0;
+
+      if (warned)
+	my_syslog(LOG_ERR, _("Failed to create SHA-256 hash object"));
+      warned = 1;
+     
+      return dummy;
+    }
+  
+  for (q = ntohs(header->qdcount); q != 0; q--) 
+    {
+      char *cp, c;
+
+      if (!extract_name(header, plen, &p, name, 1, 4))
+	break; /* bad packet */
+
+      for (cp = name; (c = *cp); cp++)
+	 if (c >= 'A' && c <= 'Z')
+	   *cp += 'a' - 'A';
+
+      hash->update(ctx, cp - name, (unsigned char *)name);
+      /* CRC the class and type as well */
+      hash->update(ctx, 4, p);
+
+      p += 4;
+      if (!CHECK_LEN(header, p, plen, 0))
+	break; /* bad packet */
+    }
+  
+  hash->digest(ctx, hash->digest_size, digest);
+  return digest;
+}
+
+#else /* HAVE_DNSSEC */
+
+#define SHA256_BLOCK_SIZE 32            // SHA256 outputs a 32 byte digest
+typedef unsigned char BYTE;             // 8-bit byte
+typedef unsigned int  WORD;             // 32-bit word, change to "long" for 16-bit machines
+
+typedef struct {
+  BYTE data[64];
+  WORD datalen;
+  unsigned long long bitlen;
+  WORD state[8];
+} SHA256_CTX;
+
+static void sha256_init(SHA256_CTX *ctx);
+static void sha256_update(SHA256_CTX *ctx, const BYTE data[], size_t len);
+static void sha256_final(SHA256_CTX *ctx, BYTE hash[]);
+
+
+unsigned char *hash_questions(struct dns_header *header, size_t plen, char *name)
+{
+  int q;
+  unsigned char *p = (unsigned char *)(header+1);
+  SHA256_CTX ctx;
+  static BYTE digest[SHA256_BLOCK_SIZE];
+  
+  sha256_init(&ctx);
+    
+  for (q = ntohs(header->qdcount); q != 0; q--) 
+    {
+      char *cp, c;
+
+      if (!extract_name(header, plen, &p, name, 1, 4))
+	break; /* bad packet */
+
+      for (cp = name; (c = *cp); cp++)
+	 if (c >= 'A' && c <= 'Z')
+	   *cp += 'a' - 'A';
+
+      sha256_update(&ctx, (BYTE *)name, cp - name);
+      /* CRC the class and type as well */
+      sha256_update(&ctx, (BYTE *)p, 4);
+
+      p += 4;
+      if (!CHECK_LEN(header, p, plen, 0))
+	break; /* bad packet */
+    }
+  
+  sha256_final(&ctx, digest);
+  return (unsigned char *)digest;
+}
+
+/* Code from here onwards comes from https://github.com/B-Con/crypto-algorithms
+   and was written by Brad Conte (brad@bradconte.com), to whom all credit is given.
+
+   This code is in the public domain, and the copyright notice at the head of this 
+   file does not apply to it.
+*/
+
+
+/****************************** MACROS ******************************/
+#define ROTLEFT(a,b) (((a) << (b)) | ((a) >> (32-(b))))
+#define ROTRIGHT(a,b) (((a) >> (b)) | ((a) << (32-(b))))
+
+#define CH(x,y,z) (((x) & (y)) ^ (~(x) & (z)))
+#define MAJ(x,y,z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
+#define EP0(x) (ROTRIGHT(x,2) ^ ROTRIGHT(x,13) ^ ROTRIGHT(x,22))
+#define EP1(x) (ROTRIGHT(x,6) ^ ROTRIGHT(x,11) ^ ROTRIGHT(x,25))
+#define SIG0(x) (ROTRIGHT(x,7) ^ ROTRIGHT(x,18) ^ ((x) >> 3))
+#define SIG1(x) (ROTRIGHT(x,17) ^ ROTRIGHT(x,19) ^ ((x) >> 10))
+
+/**************************** VARIABLES *****************************/
+static const WORD k[64] = {
+			   0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,
+			   0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,
+			   0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,
+			   0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,
+			   0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,
+			   0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070,
+			   0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,
+			   0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2
+};
+
+/*********************** FUNCTION DEFINITIONS ***********************/
+static void sha256_transform(SHA256_CTX *ctx, const BYTE data[])
+{
+  WORD a, b, c, d, e, f, g, h, i, j, t1, t2, m[64];
+  
+  for (i = 0, j = 0; i < 16; ++i, j += 4)
+    m[i] = (data[j] << 24) | (data[j + 1] << 16) | (data[j + 2] << 8) | (data[j + 3]);
+  for ( ; i < 64; ++i)
+    m[i] = SIG1(m[i - 2]) + m[i - 7] + SIG0(m[i - 15]) + m[i - 16];
+
+  a = ctx->state[0];
+  b = ctx->state[1];
+  c = ctx->state[2];
+  d = ctx->state[3];
+  e = ctx->state[4];
+  f = ctx->state[5];
+  g = ctx->state[6];
+  h = ctx->state[7];
+
+  for (i = 0; i < 64; ++i)
+    {
+      t1 = h + EP1(e) + CH(e,f,g) + k[i] + m[i];
+      t2 = EP0(a) + MAJ(a,b,c);
+      h = g;
+      g = f;
+      f = e;
+      e = d + t1;
+      d = c;
+      c = b;
+      b = a;
+      a = t1 + t2;
+    }
+  
+  ctx->state[0] += a;
+  ctx->state[1] += b;
+  ctx->state[2] += c;
+  ctx->state[3] += d;
+  ctx->state[4] += e;
+  ctx->state[5] += f;
+  ctx->state[6] += g;
+  ctx->state[7] += h;
+}
+
+static void sha256_init(SHA256_CTX *ctx)
+{
+  ctx->datalen = 0;
+  ctx->bitlen = 0;
+  ctx->state[0] = 0x6a09e667;
+  ctx->state[1] = 0xbb67ae85;
+  ctx->state[2] = 0x3c6ef372;
+  ctx->state[3] = 0xa54ff53a;
+  ctx->state[4] = 0x510e527f;
+  ctx->state[5] = 0x9b05688c;
+  ctx->state[6] = 0x1f83d9ab;
+  ctx->state[7] = 0x5be0cd19;
+}
+
+static void sha256_update(SHA256_CTX *ctx, const BYTE data[], size_t len)
+{
+  WORD i;
+  
+  for (i = 0; i < len; ++i)
+    {
+      ctx->data[ctx->datalen] = data[i];
+      ctx->datalen++;
+      if (ctx->datalen == 64) {
+	sha256_transform(ctx, ctx->data);
+	ctx->bitlen += 512;
+	ctx->datalen = 0;
+      }
+    }
+}
+
+static void sha256_final(SHA256_CTX *ctx, BYTE hash[])
+{
+  WORD i;
+  
+  i = ctx->datalen;
+
+  // Pad whatever data is left in the buffer.
+  if (ctx->datalen < 56)
+    {
+      ctx->data[i++] = 0x80;
+      while (i < 56)
+	ctx->data[i++] = 0x00;
+    }
+  else
+    {
+      ctx->data[i++] = 0x80;
+      while (i < 64)
+	ctx->data[i++] = 0x00;
+      sha256_transform(ctx, ctx->data);
+      memset(ctx->data, 0, 56);
+    }
+  
+  // Append to the padding the total message's length in bits and transform.
+  ctx->bitlen += ctx->datalen * 8;
+  ctx->data[63] = ctx->bitlen;
+  ctx->data[62] = ctx->bitlen >> 8;
+  ctx->data[61] = ctx->bitlen >> 16;
+  ctx->data[60] = ctx->bitlen >> 24;
+  ctx->data[59] = ctx->bitlen >> 32;
+  ctx->data[58] = ctx->bitlen >> 40;
+  ctx->data[57] = ctx->bitlen >> 48;
+  ctx->data[56] = ctx->bitlen >> 56;
+  sha256_transform(ctx, ctx->data);
+  
+  // Since this implementation uses little endian byte ordering and SHA uses big endian,
+  // reverse all the bytes when copying the final state to the output hash.
+  for (i = 0; i < 4; ++i)
+    {
+      hash[i]      = (ctx->state[0] >> (24 - i * 8)) & 0x000000ff;
+      hash[i + 4]  = (ctx->state[1] >> (24 - i * 8)) & 0x000000ff;
+      hash[i + 8]  = (ctx->state[2] >> (24 - i * 8)) & 0x000000ff;
+      hash[i + 12] = (ctx->state[3] >> (24 - i * 8)) & 0x000000ff;
+      hash[i + 16] = (ctx->state[4] >> (24 - i * 8)) & 0x000000ff;
+      hash[i + 20] = (ctx->state[5] >> (24 - i * 8)) & 0x000000ff;
+      hash[i + 24] = (ctx->state[6] >> (24 - i * 8)) & 0x000000ff;
+      hash[i + 28] = (ctx->state[7] >> (24 - i * 8)) & 0x000000ff;
+    }
+}
+
+#endif
--- src/rfc1035.c.orig
+++ src/rfc1035.c
@@ -335,55 +335,6 @@ unsigned char *skip_section(unsigned cha
   return ansp;
 }
 
-/* CRC the question section. This is used to safely detect query 
-   retransmission and to detect answers to questions we didn't ask, which 
-   might be poisoning attacks. Note that we decode the name rather 
-   than CRC the raw bytes, since replies might be compressed differently. 
-   We ignore case in the names for the same reason. Return all-ones
-   if there is not question section. */
-#ifndef HAVE_DNSSEC
-unsigned int questions_crc(struct dns_header *header, size_t plen, char *name)
-{
-  int q;
-  unsigned int crc = 0xffffffff;
-  unsigned char *p1, *p = (unsigned char *)(header+1);
-
-  for (q = ntohs(header->qdcount); q != 0; q--) 
-    {
-      if (!extract_name(header, plen, &p, name, 1, 4))
-	return crc; /* bad packet */
-      
-      for (p1 = (unsigned char *)name; *p1; p1++)
-	{
-	  int i = 8;
-	  char c = *p1;
-
-	  if (c >= 'A' && c <= 'Z')
-	    c += 'a' - 'A';
-
-	  crc ^= c << 24;
-	  while (i--)
-	    crc = crc & 0x80000000 ? (crc << 1) ^ 0x04c11db7 : crc << 1;
-	}
-      
-      /* CRC the class and type as well */
-      for (p1 = p; p1 < p+4; p1++)
-	{
-	  int i = 8;
-	  crc ^= *p1 << 24;
-	  while (i--)
-	    crc = crc & 0x80000000 ? (crc << 1) ^ 0x04c11db7 : crc << 1;
-	}
-
-      p += 4;
-      if (!CHECK_LEN(header, p, plen, 0))
-	return crc; /* bad packet */
-    }
-
-  return crc;
-}
-#endif
-
 size_t resize_packet(struct dns_header *header, size_t plen, unsigned char *pheader, size_t hlen)
 {
   unsigned char *ansp = skip_questions(header, plen);
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