X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Faddrfam.c;h=0ba204920529b980927374a75feca4bae51b389a;hb=7ba7a232de0516d2cce934bdc91627b33b46ef47;hp=3bddabd349fd3e8a7803c8b19c020db6fbfd1c5f;hpb=51cb3de39ef4e85d2efa7d167dc531d04500a525;p=adns.git

diff --git a/src/addrfam.c b/src/addrfam.c
index 3bddabd..0ba2049 100644
--- a/src/addrfam.c
+++ b/src/addrfam.c
@@ -4,14 +4,15 @@
  */
 /*
  *  This file is part of adns, which is
- *    Copyright (C) 1997-2000,2003,2006  Ian Jackson
+ *    Copyright (C) 1997-2000,2003,2006,2014-2016  Ian Jackson
+ *    Copyright (C) 2014  Mark Wooding
  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
  *    Copyright (C) 1991 Massachusetts Institute of Technology
  *  (See the file INSTALL for full details.)
  *  
  *  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; either version 2, or (at your option)
+ *  the Free Software Foundation; either version 3, or (at your option)
  *  any later version.
  *  
  *  This program is distributed in the hope that it will be useful,
@@ -20,8 +21,7 @@
  *  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, write to the Free Software Foundation,
- *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 
+ *  along with this program; if not, write to the Free Software Foundation.
  */
 
 #include <stdlib.h>
@@ -44,175 +44,181 @@
  * General address-family operations.
  */
 
-#define SIN(sa) ((struct sockaddr_in *)(sa))
-#define CSIN(sa) ((const struct sockaddr_in *)(sa))
-
-#define SIN6(sa) ((struct sockaddr_in6 *)(sa))
-#define CSIN6(sa) ((const struct sockaddr_in6 *)(sa))
-
-/* This gadget (thanks, Richard Kettlewell) makes sure that we handle the
- * same set of address families in each switch. */
-#define AF_CASES(pre)							\
-  case AF_INET: goto pre##_inet;					\
-  case AF_INET6: goto pre##_inet6
+#define SIN(cnst, sa) ((void)(sa)->sa_family, (cnst struct sockaddr_in *)(sa))
+#define SIN6(cnst, sa) ((void)(sa)->sa_family, (cnst struct sockaddr_in6 *)(sa))
 
+static void unknown_af(int af) NONRETURNING;
 static void unknown_af(int af) {
   fprintf(stderr, "ADNS INTERNAL: unknown address family %d\n", af);
   abort();
 }
 
-#define IN6_ADDR_EQUALP(a, b)						\
-  (!memcmp((a).s6_addr, (b).s6_addr, sizeof((a).s6_addr)))
-
-int adns__genaddr_equal_p(int af, const union gen_addr *a,
-			  int bf, const void *b) {
-  const union gen_addr *bb= b;
-  if (af != bf) return 0;
-  switch (af) {
-  AF_CASES(af);
-  af_inet: return a->v4.s_addr == bb->v4.s_addr;
-  af_inet6: return IN6_ADDR_EQUALP(a->v6, bb->v6);
-  default: unknown_af(af); return -1;
+/*
+ * SOCKADDR_IN_IN6(CNST, struct sockaddr *sa, SIN, {
+ *     // struct sockaddr_in *const SIN; // implicitly
+ *     code for inet;
+ *   }, {
+ *     // struct sockaddr_in6 *const SIN6; // implicitly
+ *     code for inet6;
+ *   })
+ *
+ * SOCKADDR_IN_IN6_PAIR(CNST, struct sockaddr *sa, SINA,
+ *                            struct sockaddr *sb, SINB, {
+ *     // struct sockaddr_in *const SINA; // implicitly
+ *     // struct sockaddr_in *const SINB; // implicitly
+ *     code for inet;
+ *   },{
+ *     // struct sockaddr_in6 *const SINA6; // implicitly
+ *     // struct sockaddr_in6 *const SINB6; // implicitly
+ *     code for inet6;
+ *   });
+ *
+ * SOCKADDR_IN_IN6_OTHER(CNST, struct sockaddr *sa, SIN, { in }, { in6 }, {
+ *     code for other address family
+ *   })
+ *
+ * AF_IN_IN6_OTHER(af, { in }, { in6 }, { other })
+ *
+ * Executes the first or second block according to the AF in sa.  CNST
+ * may be `const' or empty.  For _PAIR, sa and sb must be same AF.
+ *
+ * All except _OTHER handle unknown AFs with unknown_af.
+ *
+ * Code blocks may not contain , outside parens.
+ */
+#define AF_IN_IN6_OTHER(af, for_inet, for_inet6, other)	\
+  if ((af) == AF_INET) {					\
+    for_inet							\
+  } else if ((af) == AF_INET6) {				\
+    for_inet6							\
+  } else {							\
+    other							\
   }
+#define SOCKADDR_IN_IN6_OTHER(cnst, sa, sin, for_inet, for_inet6, other) \
+  AF_IN_IN6_OTHER((sa)->sa_family, {					\
+      cnst struct sockaddr_in *const sin = SIN(cnst,(sa));		\
+      for_inet								\
+  }, {									\
+      cnst struct sockaddr_in6 *const sin##6 = SIN6(cnst,(sa));		\
+      for_inet6								\
+  },									\
+    other								\
+  )
+#define SOCKADDR_IN_IN6(cnst, sa, sin, for_inet, for_inet6)		\
+  SOCKADDR_IN_IN6_OTHER(cnst, sa, sin, for_inet, for_inet6, {	\
+      unknown_af((sa)->sa_family);					\
+  })
+#define SOCKADDR_IN_IN6_PAIR(cnst, sa, sina, sb, sinb, for_inet, for_inet6) \
+  do{									\
+    assert((sa)->sa_family == (sb)->sa_family);				\
+    SOCKADDR_IN_IN6(cnst, sa, sina, {					\
+        cnst struct sockaddr_in *const sinb = SIN(cnst,(sb));		\
+	for_inet							\
+      }, {								\
+        cnst struct sockaddr_in6 *const sinb##6 = SIN6(cnst,(sb));	\
+	for_inet6							\
+    });									\
+  }while(0)
+
+int adns__addrs_equal_raw(const struct sockaddr *a,
+			 int bf, const void *b) {
+  if (a->sa_family != bf) return 0;
+
+  SOCKADDR_IN_IN6(const, a, sin, {
+    return sin->sin_addr.s_addr == ((const struct in_addr*)b)->s_addr;
+  }, {
+    return !memcmp(&sin6->sin6_addr, b, sizeof(struct in6_addr));
+  });
 }
 
-int adns__sockaddr_equal_p(const struct sockaddr *sa,
-			   const struct sockaddr *sb) {
-  if (sa->sa_family != sb->sa_family) return 0;
-  switch (sa->sa_family) {
-  AF_CASES(af);
-  af_inet: {
-    const struct sockaddr_in *sina= CSIN(sa), *sinb= CSIN(sb);
-    return (sina->sin_addr.s_addr == sinb->sin_addr.s_addr &&
-	    sina->sin_port == sinb->sin_port);
-  }
-  af_inet6: {
-    /* Don't check the flowlabel.  That's apparently useful for routing
-     * performance, but doesn't affect the address in any important
-     * respect. */
-    const struct sockaddr_in6 *sin6a= CSIN6(sa), *sin6b= CSIN6(sb);
-    return (IN6_ADDR_EQUALP(sin6a->sin6_addr, sin6b->sin6_addr) &&
-	    sin6a->sin6_port == sin6b->sin6_port &&
-	    sin6a->sin6_scope_id == sin6b->sin6_scope_id);
-  }
-  default:
-    unknown_af(sa->sa_family);
-    return -1;
-  }
+int adns__addrs_equal(const adns_sockaddr *a, const adns_sockaddr *b) {
+  return adns__addrs_equal_raw(&a->sa, b->sa.sa_family,
+			       adns__sockaddr_addr(&b->sa));
+}
+
+int adns__sockaddrs_equal(const struct sockaddr *sa,
+			  const struct sockaddr *sb) {
+  if (!adns__addrs_equal_raw(sa, sb->sa_family, adns__sockaddr_addr(sb)))
+    return 0;
+  SOCKADDR_IN_IN6_PAIR(const, sa, sina, sb, sinb, {
+      return sina->sin_port == sinb->sin_port;
+    }, {
+      return sina6->sin6_port == sinb6->sin6_port &&
+             sina6->sin6_scope_id == sinb6->sin6_scope_id;
+    });
 }
 
 int adns__addr_width(int af) {
-  switch (af) {
-  AF_CASES(af);
-  af_inet: return 32;
-  af_inet6: return 128;
-  default: unknown_af(af); return -1;
-  }
+  AF_IN_IN6_OTHER(af, {
+      return 32;
+    }, {
+      return 128;
+    }, {
+      unknown_af(af);
+    });
 }
 
-void adns__prefix_mask(int af, int len, union gen_addr *mask_r) {
-  switch (af) {
-  AF_CASES(af);
-  af_inet:
-    assert(len <= 32);
-    mask_r->v4.s_addr= htonl(!len ? 0 : 0xffffffff << (32-len));
-    break;
-  af_inet6: {
-    int i= len/8, j= len%8;
-    unsigned char *m= mask_r->v6.s6_addr;
-    assert(len <= 128);
-    memset(m, 0xff, i);
-    if (j) m[i++]= (0xff << (8-j)) & 0xff;
-    memset(m+i, 0, 16-i);
-  } break;
-  default:
-    unknown_af(af);
-    break;
-  }
+void adns__prefix_mask(adns_sockaddr *sa, int len) {
+  SOCKADDR_IN_IN6(, &sa->sa, sin, {
+      assert(len <= 32);
+      sin->sin_addr.s_addr= htonl(!len ? 0 : 0xffffffff << (32-len));
+    }, {
+      int i= len/8;
+      int j= len%8;
+      unsigned char *m= sin6->sin6_addr.s6_addr;
+      assert(len <= 128);
+      memset(m, 0xff, i);
+      if (j) m[i++]= (0xff << (8-j)) & 0xff;
+      memset(m+i, 0, 16-i);
+    });
 }
 
-int adns__guess_prefix_length(int af, const union gen_addr *addr) {
-  switch (af) {
-  AF_CASES(af);
-  af_inet: {
-    unsigned a= (ntohl(addr->v4.s_addr) >> 24) & 0xff;
-    if (a < 128) return 8;
-    else if (a < 192) return 16;
-    else if (a < 224) return 24;
-    else return -1;
-  } break;
-  af_inet6:
-    return 64;
-  default:
-    unknown_af(af);
-    return -1;
-  }
+int adns__guess_prefix_length(const adns_sockaddr *sa) {
+  SOCKADDR_IN_IN6(const, &sa->sa, sin, {
+      unsigned a= (ntohl(sin->sin_addr.s_addr) >> 24) & 0xff;
+      if (a < 128) return 8;
+      else if (a < 192) return 16;
+      else if (a < 224) return 24;
+      else return -1;
+    }, {
+      (void)sin6;
+      return 64;
+    });
 }
 
-int adns__addr_match_p(int addraf, const union gen_addr *addr,
-		       int netaf, const union gen_addr *base,
-		       const union gen_addr *mask)
+int adns__addr_matches(int af, const void *addr,
+		       const adns_sockaddr *base, const adns_sockaddr *mask)
 {
-  if (addraf != netaf) return 0;
-  switch (addraf) {
-  AF_CASES(af);
-  af_inet:
-    return (addr->v4.s_addr & mask->v4.s_addr) == base->v4.s_addr;
-  af_inet6: {
-    int i;
-    const char *a= addr->v6.s6_addr;
-    const char *b= base->v6.s6_addr;
-    const char *m= mask->v6.s6_addr;
-    for (i = 0; i < 16; i++)
-      if ((a[i] & m[i]) != b[i]) return 0;
-    return 1;
-  } break;
-  default:
-    unknown_af(addraf);
-    return -1;
-  }
+  if (af != base->sa.sa_family) return 0;
+  SOCKADDR_IN_IN6_PAIR(const, &base->sa, sbase, &mask->sa, smask, {
+      const struct in_addr *v4 = addr;
+      return (v4->s_addr & smask->sin_addr.s_addr)
+	== sbase->sin_addr.s_addr;
+    }, {
+      int i;
+      const char *a= addr;
+      const char *b= sbase6->sin6_addr.s6_addr;
+      const char *m= smask6->sin6_addr.s6_addr;
+      for (i = 0; i < 16; i++)
+	if ((a[i] & m[i]) != b[i]) return 0;
+      return 1;
+    });
 }
 
-void adns__sockaddr_extract(const struct sockaddr *sa,
-			    union gen_addr *a_r, int *port_r) {
-  switch (sa->sa_family) {
-  AF_CASES(af);
-  af_inet: {
-    const struct sockaddr_in *sin = CSIN(sa);
-    if (port_r) *port_r= ntohs(sin->sin_port);
-    if (a_r) a_r->v4= sin->sin_addr;
-    break;
-  }
-  af_inet6: {
-    const struct sockaddr_in6 *sin6 = CSIN6(sa);
-    if (port_r) *port_r= ntohs(sin6->sin6_port);
-    if (a_r) a_r->v6= sin6->sin6_addr;
-    break;
-  }
-  default:
-    unknown_af(sa->sa_family);
-  }
+const void *adns__sockaddr_addr(const struct sockaddr *sa) {
+  SOCKADDR_IN_IN6(const, sa, sin, {
+      return &sin->sin_addr;
+    }, {
+      return &sin6->sin6_addr;
+    });
 }
 
-void adns__sockaddr_inject(const union gen_addr *a, int port,
-			   struct sockaddr *sa) {
-  switch (sa->sa_family) {
-  AF_CASES(af);
-  af_inet: {
-    struct sockaddr_in *sin = SIN(sa);
-    if (port != -1) sin->sin_port= htons(port);
-    if (a) sin->sin_addr= a->v4;
-    break;
-  }
-  af_inet6: {
-    struct sockaddr_in6 *sin6 = SIN6(sa);
-    if (port != -1) sin6->sin6_port= htons(port);
-    if (a) sin6->sin6_addr= a->v6;
-    break;
-  }
-  default:
-    unknown_af(sa->sa_family);
-  }
+void adns__addr_inject(const void *a, adns_sockaddr *sa) {
+  SOCKADDR_IN_IN6( , &sa->sa, sin, {
+      memcpy(&sin->sin_addr, a, sizeof(sin->sin_addr));
+    }, {
+      memcpy(&sin6->sin6_addr, a, sizeof(sin6->sin6_addr));
+    });
 }
 
 /*
@@ -244,15 +250,24 @@ static bool addrtext_our_errno(int e) {
 }
 
 static bool addrtext_scope_use_ifname(const struct sockaddr *sa) {
-  const struct in6_addr *in6= &CSIN6(sa)->sin6_addr;
+  const struct in6_addr *in6= &SIN6(const,sa)->sin6_addr;
   return
     IN6_IS_ADDR_LINKLOCAL(in6) ||
     IN6_IS_ADDR_MC_LINKLOCAL(in6);
 }
 
+static int textaddr_check_qf(adns_queryflags flags) {
+  if (flags & ~(adns_queryflags)(adns_qf_addrlit_scope_forbid|
+				 adns_qf_addrlit_scope_numeric|
+				 adns_qf_addrlit_ipv4_quadonly|
+				 0x40000000))
+    return ENOSYS;
+  return 0;
+}
+
 int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags,
 		   struct sockaddr *sa, socklen_t *salen_io) {
-  int af;
+  int r, af;
   char copybuf[INET6_ADDRSTRLEN];
   const char *parse=text;
   const char *scopestr=0;
@@ -260,6 +275,8 @@ int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags,
   void *dst;
   uint16_t *portp;
 
+  r= textaddr_check_qf(flags);  if (r) return r;
+
 #define INVAL(how) do{				\
   af_debug("invalid: %s: `%s'", how, text);	\
   return EINVAL;				\
@@ -267,9 +284,9 @@ int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags,
 
 #define AFCORE(INETx,SINx,sinx)			\
     af= AF_##INETx;				\
-    dst = &SINx(sa)->sinx##_addr;		\
-    portp = &SINx(sa)->sinx##_port;		\
-    needlen= sizeof(*SINx(sa));
+    dst = &SINx(,sa)->sinx##_addr;		\
+    portp = &SINx(,sa)->sinx##_port;		\
+    needlen= sizeof(*SINx(,sa));
 
   if (!strchr(text, ':')) { /* INET */
 
@@ -311,7 +328,7 @@ int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags,
 
   if (af == AF_INET && !(flags & adns_qf_addrlit_ipv4_quadonly)) {
     /* we have to use inet_aton to deal with non-dotted-quad literals */
-    int r= inet_aton(parse,&SIN(sa)->sin_addr);
+    int r= inet_aton(parse,&SIN(,sa)->sin_addr);
     if (!r) INVAL("inet_aton rejected");
   } else {
     int r= inet_pton(af,parse,dst);
@@ -373,7 +390,7 @@ int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags,
       }
     } /* else; !!*ep */
 
-    SIN6(sa)->sin6_scope_id= scope;
+    SIN6(,sa)->sin6_scope_id= scope;
   } /* if (scopestr) */
 
   *salen_io = needlen;
@@ -383,25 +400,28 @@ int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags,
 int adns_addr2text(const struct sockaddr *sa, adns_queryflags flags,
 		   char *buffer, int *buflen_io, int *port_r) {
   const void *src;
-  int port;
+  int r, port;
+
+  r= textaddr_check_qf(flags);  if (r) return r;
 
   if (*buflen_io < ADNS_ADDR2TEXT_BUFLEN) {
     *buflen_io = ADNS_ADDR2TEXT_BUFLEN;
     return ENOSPC;
   }
 
-  switch (sa->sa_family) {
-    AF_CASES(af);
-    af_inet:  src= &CSIN(sa)->sin_addr;    port= CSIN(sa)->sin_port;    break;
-    af_inet6: src= &CSIN6(sa)->sin6_addr;  port= CSIN6(sa)->sin6_port;  break;
-    default: return EAFNOSUPPORT;
-  }
+  SOCKADDR_IN_IN6_OTHER(const, sa, sin, {
+      src= &sin->sin_addr;    port= sin->sin_port;
+    }, {
+      src= &sin6->sin6_addr;  port= sin6->sin6_port;
+    }, {
+      return EAFNOSUPPORT;
+    });
 
   const char *ok= inet_ntop(sa->sa_family, src, buffer, *buflen_io);
   assert(ok);
 
   if (sa->sa_family == AF_INET6) {
-    uint32_t scope = CSIN6(sa)->sin6_scope_id;
+    uint32_t scope = SIN6(const,sa)->sin6_scope_id;
     if (scope) {
       if (flags & adns_qf_addrlit_scope_forbid)
 	return EINVAL;
@@ -470,19 +490,15 @@ int adns__make_reverse_domain(const struct sockaddr *sa, const char *zone,
   const unsigned char *ap;
   int i, j;
 
-  switch (sa->sa_family) {
-  AF_CASES(af);
-  af_inet:
-    req= 4 * 4;
-    if (!zone) zone= "in-addr.arpa";
-    break;
-  af_inet6:
-    req = 2 * 32;
-    if (!zone) zone= "ip6.arpa";
-    break;
-  default:
-    return ENOSYS;
-  }
+  AF_IN_IN6_OTHER(sa->sa_family, {
+      req= 4 * 4;
+      if (!zone) zone= "in-addr.arpa";
+    }, {
+      req = 2 * 32;
+      if (!zone) zone= "ip6.arpa";
+    }, {
+      return ENOSYS;
+    });
 
   req += strlen(zone) + 1;
   if (req <= bufsz)
@@ -493,143 +509,138 @@ int adns__make_reverse_domain(const struct sockaddr *sa, const char *zone,
   }
 
   *buf_io= p;
-  switch (sa->sa_family) {
-  AF_CASES(bf);
-  bf_inet:
-    aa= ntohl(CSIN(sa)->sin_addr.s_addr);
-    for (i=0; i<4; i++) {
-      p += sprintf(p, "%d", (int)(aa & 0xff));
-      *p++= '.';
-      aa >>= 8;
-    }
-    break;
-  bf_inet6:
-    ap= CSIN6(sa)->sin6_addr.s6_addr + 16;
-    for (i=0; i<16; i++) {
-      c= *--ap;
-      for (j=0; j<2; j++) {
-	y= c & 0xf;
-	*p++= (y < 10) ? y + '0' : y - 10 + 'a';
-	c >>= 4;
+  SOCKADDR_IN_IN6(const, sa, sin, {
+      aa= ntohl(sin->sin_addr.s_addr);
+      for (i=0; i<4; i++) {
+	p += sprintf(p, "%d", (int)(aa & 0xff));
 	*p++= '.';
+	aa >>= 8;
       }
-    }
-    break;
-  default:
-    unknown_af(sa->sa_family);
-  }
+    }, {
+      ap= sin6->sin6_addr.s6_addr + 16;
+      for (i=0; i<16; i++) {
+	c= *--ap;
+	for (j=0; j<2; j++) {
+	  y= c & 0xf;
+	  *p++= (y < 10) ? y + '0' : y - 10 + 'a';
+	  c >>= 4;
+	  *p++= '.';
+	}
+      }
+    });
 
   strcpy(p, zone);
   return 0;
 }
 
 
-static int inet_rev_parsecomp(const char *p, size_t n) {
-  int i= 0;
-  if (n > 3) return -1;
+#define REVPARSE_P_L(labnum)			\
+  const char *p= dgram + rps->labstart[labnum];	\
+  int l= rps->lablen[labnum]
+  /*
+   * REVPARSE_P_L(int labnum);
+   *   expects:
+   *     const char *dgram;
+   *     const struct revparse_state *rps;
+   *   produces:
+   *     const char *p; // start of label labnum in dgram
+   *     int l; // length of label in dgram
+   */
+
+static bool revparse_check_tail(struct revparse_state *rps,
+				const char *dgram, int nlabels,
+				int bodylen, const char *inarpa) {
+  int i;
 
-  while (n--) {
-    if ('0' <= *p && *p <= '9') i= 10*i + *p++ - '0';
-    else return -1;
+  if (nlabels != bodylen+2) return 0;
+  for (i=0; i<2; i++) {
+    REVPARSE_P_L(bodylen+i);
+    const char *want= !i ? inarpa : "arpa";
+    if (!adns__labels_equal(p,l, want,strlen(want))) return 0;
   }
-  return i;
+  return 1;
 }
 
-static void inet_rev_mkaddr(union gen_addr *addr, const byte *ipv) {
-  addr->v4.s_addr= htonl((ipv[3]<<24) | (ipv[2]<<16) |
-			 (ipv[1]<<8) | (ipv[0]));
+static bool revparse_atoi(const char *p, int l, int base,
+			  unsigned max, unsigned *v_r) {
+  if (l>3) return 0;
+  if (l>1 && p[0]=='0') return 0;
+  unsigned v=0;
+  while (l-- > 0) {
+    int tv;
+    int c= ctype_toupper(*p++);
+    if ('0'<=c && c<='9') tv = c-'0';
+    else if ('A'<=c && c<='Z') tv = c-'A'+10;
+    else return 0;
+    if (tv >= base) return 0;
+    v *= base;
+    v += tv;
+  }
+  if (v>max) return 0;
+  *v_r= v;
+  return 1;
 }
 
-static int inet6_rev_parsecomp(const char *p, size_t n) {
-  if (n != 1) return -1;
-  else if ('0' <= *p && *p <= '9') return *p - '0';
-  else if ('a' <= *p && *p <= 'f') return *p - 'a' + 10;
-  else if ('A' <= *p && *p <= 'F') return *p - 'a' + 10;
-  else return -1;
-}
+static bool revparse_inet(struct revparse_state *rps,
+			  const char *dgram, int nlabels,
+			  adns_rrtype *rrtype_r, adns_sockaddr *addr_r) {
+  if (!revparse_check_tail(rps,dgram,nlabels,4,"in-addr")) return 0;
 
-static void inet6_rev_mkaddr(union gen_addr *addr, const byte *ipv) {
-  unsigned char *a= addr->v6.s6_addr;
+  uint32_t a=0;
   int i;
-
-  for (i=0; i<16; i++)
-    a[i]= (ipv[31-2*i] << 4) | (ipv[30-2*i] << 0);
+  for (i=3; i>=0; i--) {
+    REVPARSE_P_L(i);
+    unsigned v;
+    if (!revparse_atoi(p,l,10,255,&v)) return 0;
+    a <<= 8;
+    a |= v;
+  }
+  *rrtype_r= adns_r_a;
+  addr_r->inet.sin_family= AF_INET;
+  addr_r->inet.sin_addr.s_addr= htonl(a);
+  return 1;
 }
 
-static const struct revparse_domain {
-  int af;				/* address family */
-  int nrevlab;				/* n of reverse-address labels */
-  adns_rrtype rrtype;			/* forward-lookup type */
-
-  int (*rev_parsecomp)(const char *p, size_t n);
-  /* parse a single component from a label; return the integer value, or -1
-   * if it was unintelligible.
-   */
+static bool revparse_inet6(struct revparse_state *rps,
+			   const char *dgram, int nlabels,
+			   adns_rrtype *rrtype_r, adns_sockaddr *addr_r) {
+  if (!revparse_check_tail(rps,dgram,nlabels,32,"ip6")) return 0;
 
-  void (*rev_mkaddr)(union gen_addr *addr, const byte *ipv);
-  /* write out the parsed address from a vector of parsed components */
-
-  const char *const tail[3];		/* tail label names */
-} revparse_domains[NREVDOMAINS] = {
-  { AF_INET, 4, adns_r_a, inet_rev_parsecomp, inet_rev_mkaddr,
-    { DNS_INADDR_ARPA, 0 } },
-  { AF_INET6, 32, adns_r_aaaa, inet6_rev_parsecomp, inet6_rev_mkaddr,
-    { DNS_IP6_ARPA, 0 } },
-};
-
-#define REVDOMAIN_MAP(rps, labnum)					\
-  ((labnum) ? (rps)->map : (1 << NREVDOMAINS) - 1)
-
-int adns__revparse_label(struct revparse_state *rps, int labnum,
-			 const char *label, int lablen) {
-  unsigned f= REVDOMAIN_MAP(rps, labnum);
-  const struct revparse_domain *rpd;
-  const char *tp;
-  unsigned d;
-  int i, ac;
-
-  for (rpd=revparse_domains, i=0, d=1; i<NREVDOMAINS; rpd++, i++, d <<= 1) {
-    if (!(f & d)) continue;
-    if (labnum >= rpd->nrevlab) {
-      tp = rpd->tail[labnum - rpd->nrevlab];
-      if (!tp || strncmp(label, tp, lablen) != 0 || tp[lablen])
-	goto mismatch;
-    } else {
-      ac= rpd->rev_parsecomp(label, lablen);
-      if (ac < 0) goto mismatch;
-      assert(labnum < sizeof(rps->ipv[i]));
-      rps->ipv[i][labnum]= ac;
+  int i, j;
+  memset(addr_r,0,sizeof(*addr_r));
+  unsigned char *a= addr_r->inet6.sin6_addr.s6_addr+16;
+  for (i=0; i<32; ) { /* i incremented in inner loop */
+    unsigned b=0;
+    for (j=0; j<2; j++, i++) {
+      REVPARSE_P_L(i);
+      unsigned v;
+      if (!revparse_atoi(p,l,16,15,&v)) return 0;
+      b >>= 4;
+      b |= v << 4;
     }
-    continue;
-
-  mismatch:
-    f &= ~d;
-    if (!f) return -1;
+    *--a= b;
   }
-
-  rps->map= f;
-  return 0;
+  *rrtype_r= adns_r_aaaa;
+  addr_r->inet.sin_family= AF_INET6;
+  return 1;
 }
 
-int adns__revparse_done(struct revparse_state *rps, int nlabels,
-			adns_rrtype *rrtype_r, struct af_addr *addr_r) {
-  unsigned f= REVDOMAIN_MAP(rps, nlabels);
-  const struct revparse_domain *rpd;
-  unsigned d;
-  int i, found= -1;
-
-  for (rpd=revparse_domains, i=0, d=1; i<NREVDOMAINS; rpd++, i++, d <<= 1) {
-    if (!(f & d)) continue;
-    if (nlabels >= rpd->nrevlab && !rpd->tail[nlabels - rpd->nrevlab])
-      { found = i; continue; }
-    f &= ~d;
-    if (!f) return -1;
-  }
-  assert(found >= 0); assert(f == (1 << found));
+bool adns__revparse_label(struct revparse_state *rps, int labnum,
+			  const char *dgram, int labstart, int lablen) {
+  if (labnum >= MAXREVLABELS)
+    return 0;
 
-  rpd= &revparse_domains[found];
-  *rrtype_r= rpd->rrtype;
-  addr_r->af= rpd->af;
-  rpd->rev_mkaddr(&addr_r->addr, rps->ipv[found]);
-  return 0;
+  assert(labstart <= 65535);
+  assert(lablen <= 255);
+  rps->labstart[labnum] = labstart;
+  rps->lablen[labnum] = lablen;
+  return 1;
+}
+
+bool adns__revparse_done(struct revparse_state *rps,
+			 const char *dgram, int nlabels,
+			 adns_rrtype *rrtype_r, adns_sockaddr *addr_r) {
+  return
+    revparse_inet(rps,dgram,nlabels,rrtype_r,addr_r) ||
+    revparse_inet6(rps,dgram,nlabels,rrtype_r,addr_r);
 }