[adns] / src / addrfam.c

/*
 * addrfam.c
 * - address-family specific code
 */
/*
 *  This file is part of adns, which is
 *    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 3, or (at your option)
 *  any later version.
 *  
 *  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, write to the Free Software Foundation.
 */

#include <stdlib.h>
#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include <inttypes.h>
#include <stddef.h>
#include <stdbool.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>

#include "internal.h"

/*
 * General address-family operations.
 */

#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();
}

/*
 * 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__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) {
  AF_IN_IN6_OTHER(af, {
      return 32;
    }, {
      return 128;
    }, {
      unknown_af(af);
    });
}

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(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_matches(int af, const void *addr,
		       const adns_sockaddr *base, const adns_sockaddr *mask)
{
  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;
    });
}

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__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));
    });
}

/*
 * addr2text and text2addr
 */

#define ADDRFAM_DEBUG
#ifdef ADDRFAM_DEBUG
static void af_debug_func(const char *fmt, ...) {
  int esave= errno;
  va_list al;
  va_start(al,fmt);
  vfprintf(stderr,fmt,al);
  va_end(al);
  errno= esave;
}
# define af_debug(fmt,...) \
  (af_debug_func("%s: " fmt "\n", __func__, __VA_ARGS__))
#else
# define af_debug(fmt,...) ((void)("" fmt "", __VA_ARGS__))
#endif

static bool addrtext_our_errno(int e) {
  return
    e==EAFNOSUPPORT ||
    e==EINVAL ||
    e==ENOSPC ||
    e==ENOSYS;
}

static bool addrtext_scope_use_ifname(const struct sockaddr *sa) {
  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 r, af;
  char copybuf[INET6_ADDRSTRLEN];
  const char *parse=text;
  const char *scopestr=0;
  socklen_t needlen;
  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;				\
}while(0)

#define AFCORE(INETx,SINx,sinx)			\
    af= AF_##INETx;				\
    dst = &SINx(,sa)->sinx##_addr;		\
    portp = &SINx(,sa)->sinx##_port;		\
    needlen= sizeof(*SINx(,sa));

  if (!strchr(text, ':')) { /* INET */

    AFCORE(INET,SIN,sin);

  } else { /* INET6 */

    AFCORE(INET6,SIN6,sin6);

    const char *percent= strchr(text, '%');
    if (percent) {
      ptrdiff_t lhslen = percent - text;
      if (lhslen >= INET6_ADDRSTRLEN) INVAL("scoped addr lhs too long");
      memcpy(copybuf, text, lhslen);
      copybuf[lhslen]= 0;

      parse= copybuf;
      scopestr= percent+1;

      af_debug("will parse scoped addr `%s' %% `%s'", parse, scopestr);
    }

  }

#undef AFCORE

  if (scopestr && (flags & adns_qf_addrlit_scope_forbid))
    INVAL("scoped addr but _scope_forbid");

  if (*salen_io < needlen) {
    *salen_io = needlen;
    return ENOSPC;
  }

  memset(sa, 0, needlen);

  sa->sa_family= af;
  *portp = htons(port);

  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);
    if (!r) INVAL("inet_aton rejected");
  } else {
    int r= inet_pton(af,parse,dst);
    if (!r) INVAL("inet_pton rejected");
    assert(r>0);
  }

  if (scopestr) {
    errno=0;
    char *ep;
    unsigned long scope= strtoul(scopestr,&ep,10);
    if (errno==ERANGE) INVAL("numeric scope id too large for unsigned long");
    assert(!errno);
    if (!*ep) {
      if (scope > ~(uint32_t)0)
	INVAL("numeric scope id too large for uint32_t");
    } else { /* !!*ep */
      if (flags & adns_qf_addrlit_scope_numeric)
	INVAL("non-numeric scope but _scope_numeric");
      if (!addrtext_scope_use_ifname(sa)) {
	af_debug("cannot convert non-numeric scope"
		 " in non-link-local addr `%s'", text);
	return ENOSYS;
      }
      errno= 0;
      scope= if_nametoindex(scopestr);
      if (!scope) {
	/* RFC3493 says "No errors are defined".  It's not clear
	 * whether that is supposed to mean if_nametoindex "can't
	 * fail" (other than by the supplied name not being that of an
	 * interface) which seems unrealistic, or that it conflates
	 * all its errors together by failing to set errno, or simply
	 * that they didn't bother to document the errors.
	 *
	 * glibc, FreeBSD and OpenBSD all set errno (to ENXIO when
	 * appropriate).  See Debian bug #749349.
	 *
	 * We attempt to deal with this by clearing errno to start
	 * with, and then perhaps mapping the results. */
	af_debug("if_nametoindex rejected scope name (errno=%s)",
		 strerror(errno));
	if (errno==0) {
	  return ENXIO;
	} else if (addrtext_our_errno(errno)) {
	  /* we use these for other purposes, urgh. */
	  perror("adns: adns_text2addr: if_nametoindex"
		 " failed with unexpected error");
	  return EIO;
	} else {
	  return errno;
	}
      } else { /* ix>0 */
	if (scope > ~(uint32_t)0) {
	  fprintf(stderr,"adns: adns_text2addr: if_nametoindex"
		  " returned an interface index >=2^32 which will not fit"
		  " in sockaddr_in6.sin6_scope_id");
	  return EIO;
	}
      }
    } /* else; !!*ep */

    SIN6(,sa)->sin6_scope_id= scope;
  } /* if (scopestr) */

  *salen_io = needlen;
  return 0;
}

int adns_addr2text(const struct sockaddr *sa, adns_queryflags flags,
		   char *buffer, int *buflen_io, int *port_r) {
  const void *src;
  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;
  }

  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 = SIN6(const,sa)->sin6_scope_id;
    if (scope) {
      if (flags & adns_qf_addrlit_scope_forbid)
	return EINVAL;
      int scopeoffset = strlen(buffer);
      int remain = *buflen_io - scopeoffset;
      char *scopeptr =  buffer + scopeoffset;
      assert(remain >= IF_NAMESIZE+1/*%*/);
      *scopeptr++= '%'; remain--;
      bool parsedname = 0;
      af_debug("will print scoped addr `%.*s' %% %"PRIu32"",
	       scopeoffset,buffer, scope);
      if (scope <= UINT_MAX /* so we can pass it to if_indextoname */
	  && !(flags & adns_qf_addrlit_scope_numeric)
	  && addrtext_scope_use_ifname(sa)) {
	parsedname = if_indextoname(scope, scopeptr);
	if (!parsedname) {
	  af_debug("if_indextoname rejected scope (errno=%s)",
		   strerror(errno));
	  if (errno==ENXIO) {
	    /* fair enough, show it as a number then */
	  } else if (addrtext_our_errno(errno)) {
	    /* we use these for other purposes, urgh. */
	    perror("adns: adns_addr2text: if_indextoname"
		   " failed with unexpected error");
	    return EIO;
	  } else {
	    return errno;
	  }
	}
      }
      if (!parsedname) {
	int r = snprintf(scopeptr, remain,
			 "%"PRIu32"", scope);
	assert(r < *buflen_io - scopeoffset);
      }
      af_debug("printed scoped addr `%s'", buffer);
    }
  }

  if (port_r) *port_r= ntohs(port);
  return 0;
}

char *adns__sockaddr_ntoa(const struct sockaddr *sa, char *buf) {
  int err;
  int len= ADNS_ADDR2TEXT_BUFLEN;

  err= adns_addr2text(sa, 0, buf, &len, 0);
  if (err == EIO)
    err= adns_addr2text(sa, adns_qf_addrlit_scope_numeric, buf, &len, 0);
  assert(!err);
  return buf;
}

/*
 * Reverse-domain parsing and construction.
 */

int adns__make_reverse_domain(const struct sockaddr *sa, const char *zone,
			      char **buf_io, size_t bufsz,
			      char **buf_free_r) {
  size_t req;
  char *p;
  unsigned c, y;
  unsigned long aa;
  const unsigned char *ap;
  int i, j;

  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)
    p= *buf_io;
  else {
    p= malloc(req); if (!p) return errno;
    *buf_free_r = p;
  }

  *buf_io= p;
  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;
      }
    }, {
      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;
}


#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;

  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 1;
}

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 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;

  uint32_t a=0;
  int i;
  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 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;

  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;
    }
    *--a= b;
  }
  *rrtype_r= adns_r_aaaa;
  addr_r->inet.sin_family= AF_INET6;
  return 1;
}

bool adns__revparse_label(struct revparse_state *rps, int labnum,
			  const char *dgram, int labstart, int lablen) {
  if (labnum >= MAXREVLABELS)
    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);
}
Commit	Line	Data
07554ccd MW	1	/*
	2	* addrfam.c
	3	* - address-family specific code
	4	*/
	5	/*
	6	* This file is part of adns, which is
baa953c9	7	* Copyright (C) 1997-2000,2003,2006,2014-2016 Ian Jackson
17cd4f48	8	* Copyright (C) 2014 Mark Wooding
07554ccd MW	9	* Copyright (C) 1999-2000,2003,2006 Tony Finch
	10	* Copyright (C) 1991 Massachusetts Institute of Technology
	11	* (See the file INSTALL for full details.)
	12	*
	13	* This program is free software; you can redistribute it and/or modify
	14	* it under the terms of the GNU General Public License as published by
7f8bbe29	15	* the Free Software Foundation; either version 3, or (at your option)
07554ccd MW	16	* any later version.
	17	*
	18	* This program is distributed in the hope that it will be useful,
	19	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	20	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	21	* GNU General Public License for more details.
	22	*
	23	* You should have received a copy of the GNU General Public License
8c09a4c6	24	* along with this program; if not, write to the Free Software Foundation.
07554ccd MW	25	*/
	26
	27	#include <stdlib.h>
	28	#include <errno.h>
	29	#include <limits.h>
	30	#include <unistd.h>
5806b745 IJ	31	#include <inttypes.h>
	32	#include <stddef.h>
	33	#include <stdbool.h>
07554ccd MW	34
	35	#include <sys/types.h>
	36	#include <sys/socket.h>
	37	#include <netinet/in.h>
	38	#include <arpa/inet.h>
5806b745	39	#include <net/if.h>
07554ccd MW	40
	41	#include "internal.h"
	42
	43	/*
	44	* General address-family operations.
	45	*/
	46
468a4293 IJ	47	#define SIN(cnst, sa) ((void)(sa)->sa_family, (cnst struct sockaddr_in *)(sa))
468a4293 IJ	48	#define SIN6(cnst, sa) ((void)(sa)->sa_family, (cnst struct sockaddr_in6 *)(sa))
07554ccd	49
6380363d	50	static void unknown_af(int af) NONRETURNING;
07554ccd MW	51	static void unknown_af(int af) {
	52	fprintf(stderr, "ADNS INTERNAL: unknown address family %d\n", af);
	53	abort();
	54	}
	55
e0fc85c4 IJ	56	/*
	57	* SOCKADDR_IN_IN6(CNST, struct sockaddr *sa, SIN, {
	58	* // struct sockaddr_in *const SIN; // implicitly
	59	* code for inet;
	60	* }, {
	61	* // struct sockaddr_in6 *const SIN6; // implicitly
	62	* code for inet6;
	63	* })
	64	*
	65	* SOCKADDR_IN_IN6_PAIR(CNST, struct sockaddr *sa, SINA,
	66	* struct sockaddr *sb, SINB, {
	67	* // struct sockaddr_in *const SINA; // implicitly
	68	* // struct sockaddr_in *const SINB; // implicitly
	69	* code for inet;
	70	* },{
	71	* // struct sockaddr_in6 *const SINA6; // implicitly
	72	* // struct sockaddr_in6 *const SINB6; // implicitly
	73	* code for inet6;
	74	* });
	75	*
	76	* SOCKADDR_IN_IN6_OTHER(CNST, struct sockaddr *sa, SIN, { in }, { in6 }, {
	77	* code for other address family
	78	* })
	79	*
	80	* AF_IN_IN6_OTHER(af, { in }, { in6 }, { other })
	81	*
	82	* Executes the first or second block according to the AF in sa. CNST
	83	* may be `const' or empty. For _PAIR, sa and sb must be same AF.
	84	*
	85	* All except _OTHER handle unknown AFs with unknown_af.
	86	*
	87	* Code blocks may not contain , outside parens.
	88	*/
	89	#define AF_IN_IN6_OTHER(af, for_inet, for_inet6, other) \
	90	if ((af) == AF_INET) { \
	91	for_inet \
	92	} else if ((af) == AF_INET6) { \
	93	for_inet6 \
	94	} else { \
	95	other \
	96	}
	97	#define SOCKADDR_IN_IN6_OTHER(cnst, sa, sin, for_inet, for_inet6, other) \
468a4293 IJ	98	AF_IN_IN6_OTHER((sa)->sa_family, { \
468a4293 IJ	99	cnst struct sockaddr_in *const sin = SIN(cnst,(sa)); \
e0fc85c4 IJ	100	for_inet \
e0fc85c4 IJ	101	}, { \
468a4293	102	cnst struct sockaddr_in6 *const sin##6 = SIN6(cnst,(sa)); \
e0fc85c4 IJ	103	for_inet6 \
	104	}, \
	105	other \
	106	)
	107	#define SOCKADDR_IN_IN6(cnst, sa, sin, for_inet, for_inet6) \
	108	SOCKADDR_IN_IN6_OTHER(cnst, sa, sin, for_inet, for_inet6, { \
	109	unknown_af((sa)->sa_family); \
	110	})
	111	#define SOCKADDR_IN_IN6_PAIR(cnst, sa, sina, sb, sinb, for_inet, for_inet6) \
	112	do{ \
	113	assert((sa)->sa_family == (sb)->sa_family); \
	114	SOCKADDR_IN_IN6(cnst, sa, sina, { \
468a4293	115	cnst struct sockaddr_in *const sinb = SIN(cnst,(sb)); \
e0fc85c4	116	for_inet \
468a4293 IJ	117	}, { \
468a4293 IJ	118	cnst struct sockaddr_in6 *const sinb##6 = SIN6(cnst,(sb)); \
e0fc85c4 IJ	119	for_inet6 \
	120	}); \
	121	}while(0)
	122
82ae109e IJ	123	int adns__addrs_equal_raw(const struct sockaddr *a,
	124	int bf, const void *b) {
	125	if (a->sa_family != bf) return 0;
e0fc85c4 IJ	126
	127	SOCKADDR_IN_IN6(const, a, sin, {
	128	return sin->sin_addr.s_addr == ((const struct in_addr*)b)->s_addr;
	129	}, {
	130	return !memcmp(&sin6->sin6_addr, b, sizeof(struct in6_addr));
	131	});
07554ccd MW	132	}
07554ccd MW	133
82ae109e IJ	134	int adns__addrs_equal(const adns_sockaddr a, const adns_sockaddr b) {
	135	return adns__addrs_equal_raw(&a->sa, b->sa.sa_family,
	136	adns__sockaddr_addr(&b->sa));
	137	}
	138
	139	int adns__sockaddrs_equal(const struct sockaddr *sa,
	140	const struct sockaddr *sb) {
	141	if (!adns__addrs_equal_raw(sa, sb->sa_family, adns__sockaddr_addr(sb)))
	142	return 0;
e0fc85c4 IJ	143	SOCKADDR_IN_IN6_PAIR(const, sa, sina, sb, sinb, {
	144	return sina->sin_port == sinb->sin_port;
	145	}, {
	146	return sina6->sin6_port == sinb6->sin6_port &&
	147	sina6->sin6_scope_id == sinb6->sin6_scope_id;
	148	});
07554ccd MW	149	}
	150
	151	int adns__addr_width(int af) {
e0fc85c4 IJ	152	AF_IN_IN6_OTHER(af, {
	153	return 32;
	154	}, {
	155	return 128;
	156	}, {
	157	unknown_af(af);
	158	});
07554ccd MW	159	}
07554ccd MW	160
82ae109e	161	void adns__prefix_mask(adns_sockaddr *sa, int len) {
e0fc85c4 IJ	162	SOCKADDR_IN_IN6(, &sa->sa, sin, {
	163	assert(len <= 32);
	164	sin->sin_addr.s_addr= htonl(!len ? 0 : 0xffffffff << (32-len));
	165	}, {
	166	int i= len/8;
	167	int j= len%8;
	168	unsigned char *m= sin6->sin6_addr.s6_addr;
	169	assert(len <= 128);
	170	memset(m, 0xff, i);
	171	if (j) m[i++]= (0xff << (8-j)) & 0xff;
	172	memset(m+i, 0, 16-i);
	173	});
07554ccd MW	174	}
07554ccd MW	175
82ae109e	176	int adns__guess_prefix_length(const adns_sockaddr *sa) {
e0fc85c4 IJ	177	SOCKADDR_IN_IN6(const, &sa->sa, sin, {
	178	unsigned a= (ntohl(sin->sin_addr.s_addr) >> 24) & 0xff;
	179	if (a < 128) return 8;
	180	else if (a < 192) return 16;
	181	else if (a < 224) return 24;
	182	else return -1;
	183	}, {
	184	(void)sin6;
	185	return 64;
	186	});
07554ccd MW	187	}
07554ccd MW	188
82ae109e IJ	189	int adns__addr_matches(int af, const void *addr,
82ae109e IJ	190	const adns_sockaddr base, const adns_sockaddr mask)
07554ccd	191	{
82ae109e	192	if (af != base->sa.sa_family) return 0;
e0fc85c4 IJ	193	SOCKADDR_IN_IN6_PAIR(const, &base->sa, sbase, &mask->sa, smask, {
	194	const struct in_addr *v4 = addr;
	195	return (v4->s_addr & smask->sin_addr.s_addr)
	196	== sbase->sin_addr.s_addr;
	197	}, {
	198	int i;
	199	const char *a= addr;
	200	const char *b= sbase6->sin6_addr.s6_addr;
	201	const char *m= smask6->sin6_addr.s6_addr;
	202	for (i = 0; i < 16; i++)
	203	if ((a[i] & m[i]) != b[i]) return 0;
	204	return 1;
	205	});
07554ccd MW	206	}
07554ccd MW	207
82ae109e	208	const void adns__sockaddr_addr(const struct sockaddr sa) {
e0fc85c4 IJ	209	SOCKADDR_IN_IN6(const, sa, sin, {
	210	return &sin->sin_addr;
	211	}, {
	212	return &sin6->sin6_addr;
	213	});
07554ccd MW	214	}
07554ccd MW	215
82ae109e	216	void adns__addr_inject(const void a, adns_sockaddr sa) {
e0fc85c4 IJ	217	SOCKADDR_IN_IN6( , &sa->sa, sin, {
	218	memcpy(&sin->sin_addr, a, sizeof(sin->sin_addr));
	219	}, {
	220	memcpy(&sin6->sin6_addr, a, sizeof(sin6->sin6_addr));
	221	});
07554ccd	222	}
5806b745 IJ	223
	224	/*
	225	* addr2text and text2addr
	226	*/
	227
	228	#define ADDRFAM_DEBUG
	229	#ifdef ADDRFAM_DEBUG
	230	static void af_debug_func(const char *fmt, ...) {
	231	int esave= errno;
	232	va_list al;
	233	va_start(al,fmt);
	234	vfprintf(stderr,fmt,al);
	235	va_end(al);
	236	errno= esave;
	237	}
	238	# define af_debug(fmt,...) \
	239	(af_debug_func("%s: " fmt "\n", __func__, __VA_ARGS__))
	240	#else
	241	# define af_debug(fmt,...) ((void)("" fmt "", __VA_ARGS__))
	242	#endif
	243
	244	static bool addrtext_our_errno(int e) {
	245	return
	246	e==EAFNOSUPPORT \|\|
	247	e==EINVAL \|\|
	248	e==ENOSPC \|\|
	249	e==ENOSYS;
	250	}
	251
	252	static bool addrtext_scope_use_ifname(const struct sockaddr *sa) {
468a4293	253	const struct in6_addr *in6= &SIN6(const,sa)->sin6_addr;
5806b745 IJ	254	return
	255	IN6_IS_ADDR_LINKLOCAL(in6) \|\|
	256	IN6_IS_ADDR_MC_LINKLOCAL(in6);
	257	}
	258
039a0566 IJ	259	static int textaddr_check_qf(adns_queryflags flags) {
	260	if (flags & ~(adns_queryflags)(adns_qf_addrlit_scope_forbid\|
	261	adns_qf_addrlit_scope_numeric\|
	262	adns_qf_addrlit_ipv4_quadonly\|
	263	0x40000000))
	264	return ENOSYS;
	265	return 0;
	266	}
	267
5806b745 IJ	268	int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags,
5806b745 IJ	269	struct sockaddr sa, socklen_t salen_io) {
039a0566	270	int r, af;
5806b745 IJ	271	char copybuf[INET6_ADDRSTRLEN];
	272	const char *parse=text;
	273	const char *scopestr=0;
	274	socklen_t needlen;
	275	void *dst;
	276	uint16_t *portp;
	277
039a0566 IJ	278	r= textaddr_check_qf(flags); if (r) return r;
039a0566 IJ	279
5806b745 IJ	280	#define INVAL(how) do{ \
	281	af_debug("invalid: %s: `%s'", how, text); \
	282	return EINVAL; \
	283	}while(0)
	284
	285	#define AFCORE(INETx,SINx,sinx) \
	286	af= AF_##INETx; \
468a4293 IJ	287	dst = &SINx(,sa)->sinx##_addr; \
	288	portp = &SINx(,sa)->sinx##_port; \
	289	needlen= sizeof(*SINx(,sa));
5806b745 IJ	290
	291	if (!strchr(text, ':')) { /* INET */
	292
	293	AFCORE(INET,SIN,sin);
	294
	295	} else { /* INET6 */
	296
	297	AFCORE(INET6,SIN6,sin6);
	298
	299	const char *percent= strchr(text, '%');
	300	if (percent) {
	301	ptrdiff_t lhslen = percent - text;
	302	if (lhslen >= INET6_ADDRSTRLEN) INVAL("scoped addr lhs too long");
	303	memcpy(copybuf, text, lhslen);
	304	copybuf[lhslen]= 0;
	305
	306	parse= copybuf;
	307	scopestr= percent+1;
	308
	309	af_debug("will parse scoped addr `%s' %% `%s'", parse, scopestr);
	310	}
	311
	312	}
	313
	314	#undef AFCORE
	315
	316	if (scopestr && (flags & adns_qf_addrlit_scope_forbid))
	317	INVAL("scoped addr but _scope_forbid");
	318
	319	if (*salen_io < needlen) {
	320	*salen_io = needlen;
	321	return ENOSPC;
	322	}
	323
	324	memset(sa, 0, needlen);
	325
	326	sa->sa_family= af;
	327	*portp = htons(port);
	328
	329	if (af == AF_INET && !(flags & adns_qf_addrlit_ipv4_quadonly)) {
	330	/* we have to use inet_aton to deal with non-dotted-quad literals */
468a4293	331	int r= inet_aton(parse,&SIN(,sa)->sin_addr);
5806b745 IJ	332	if (!r) INVAL("inet_aton rejected");
	333	} else {
	334	int r= inet_pton(af,parse,dst);
	335	if (!r) INVAL("inet_pton rejected");
	336	assert(r>0);
	337	}
	338
	339	if (scopestr) {
	340	errno=0;
	341	char *ep;
	342	unsigned long scope= strtoul(scopestr,&ep,10);
	343	if (errno==ERANGE) INVAL("numeric scope id too large for unsigned long");
	344	assert(!errno);
	345	if (!*ep) {
	346	if (scope > ~(uint32_t)0)
	347	INVAL("numeric scope id too large for uint32_t");
	348	} else { /* !!ep /
	349	if (flags & adns_qf_addrlit_scope_numeric)
	350	INVAL("non-numeric scope but _scope_numeric");
	351	if (!addrtext_scope_use_ifname(sa)) {
	352	af_debug("cannot convert non-numeric scope"
	353	" in non-link-local addr `%s'", text);
	354	return ENOSYS;
	355	}
	356	errno= 0;
	357	scope= if_nametoindex(scopestr);
	358	if (!scope) {
	359	/* RFC3493 says "No errors are defined". It's not clear
	360	* whether that is supposed to mean if_nametoindex "can't
	361	* fail" (other than by the supplied name not being that of an
	362	* interface) which seems unrealistic, or that it conflates
	363	* all its errors together by failing to set errno, or simply
	364	* that they didn't bother to document the errors.
	365	*
	366	* glibc, FreeBSD and OpenBSD all set errno (to ENXIO when
	367	* appropriate). See Debian bug #749349.
	368	*
	369	* We attempt to deal with this by clearing errno to start
	370	* with, and then perhaps mapping the results. */
	371	af_debug("if_nametoindex rejected scope name (errno=%s)",
	372	strerror(errno));
	373	if (errno==0) {
	374	return ENXIO;
	375	} else if (addrtext_our_errno(errno)) {
	376	/* we use these for other purposes, urgh. */
	377	perror("adns: adns_text2addr: if_nametoindex"
	378	" failed with unexpected error");
	379	return EIO;
	380	} else {
	381	return errno;
	382	}
	383	} else { /* ix>0 */
	384	if (scope > ~(uint32_t)0) {
	385	fprintf(stderr,"adns: adns_text2addr: if_nametoindex"
	386	" returned an interface index >=2^32 which will not fit"
	387	" in sockaddr_in6.sin6_scope_id");
	388	return EIO;
	389	}
	390	}
	391	} /* else; !!ep /
	392
468a4293	393	SIN6(,sa)->sin6_scope_id= scope;
5806b745 IJ	394	} /* if (scopestr) */
	395
	396	*salen_io = needlen;
	397	return 0;
	398	}
	399
	400	int adns_addr2text(const struct sockaddr *sa, adns_queryflags flags,
	401	char buffer, int buflen_io, int *port_r) {
	402	const void *src;
039a0566 IJ	403	int r, port;
	404
	405	r= textaddr_check_qf(flags); if (r) return r;
5806b745 IJ	406
	407	if (*buflen_io < ADNS_ADDR2TEXT_BUFLEN) {
	408	*buflen_io = ADNS_ADDR2TEXT_BUFLEN;
	409	return ENOSPC;
	410	}
	411
e0fc85c4 IJ	412	SOCKADDR_IN_IN6_OTHER(const, sa, sin, {
	413	src= &sin->sin_addr; port= sin->sin_port;
	414	}, {
	415	src= &sin6->sin6_addr; port= sin6->sin6_port;
	416	}, {
	417	return EAFNOSUPPORT;
	418	});
5806b745 IJ	419
	420	const char ok= inet_ntop(sa->sa_family, src, buffer, buflen_io);
	421	assert(ok);
	422
	423	if (sa->sa_family == AF_INET6) {
468a4293	424	uint32_t scope = SIN6(const,sa)->sin6_scope_id;
5806b745 IJ	425	if (scope) {
	426	if (flags & adns_qf_addrlit_scope_forbid)
	427	return EINVAL;
	428	int scopeoffset = strlen(buffer);
	429	int remain = *buflen_io - scopeoffset;
	430	char *scopeptr = buffer + scopeoffset;
	431	assert(remain >= IF_NAMESIZE+1/%/);
	432	*scopeptr++= '%'; remain--;
	433	bool parsedname = 0;
c3a165f5 MW	434	af_debug("will print scoped addr `%.*s' %% %"PRIu32"",
c3a165f5 MW	435	scopeoffset,buffer, scope);
5806b745 IJ	436	if (scope <= UINT_MAX /* so we can pass it to if_indextoname */
	437	&& !(flags & adns_qf_addrlit_scope_numeric)
	438	&& addrtext_scope_use_ifname(sa)) {
	439	parsedname = if_indextoname(scope, scopeptr);
	440	if (!parsedname) {
	441	af_debug("if_indextoname rejected scope (errno=%s)",
	442	strerror(errno));
	443	if (errno==ENXIO) {
	444	/* fair enough, show it as a number then */
	445	} else if (addrtext_our_errno(errno)) {
	446	/* we use these for other purposes, urgh. */
	447	perror("adns: adns_addr2text: if_indextoname"
	448	" failed with unexpected error");
	449	return EIO;
	450	} else {
	451	return errno;
	452	}
	453	}
	454	}
	455	if (!parsedname) {
	456	int r = snprintf(scopeptr, remain,
	457	"%"PRIu32"", scope);
	458	assert(r < *buflen_io - scopeoffset);
	459	}
	460	af_debug("printed scoped addr `%s'", buffer);
	461	}
	462	}
	463
	464	if (port_r) *port_r= ntohs(port);
	465	return 0;
	466	}
b0e8338a MW	467
	468	char adns__sockaddr_ntoa(const struct sockaddr sa, char *buf) {
	469	int err;
	470	int len= ADNS_ADDR2TEXT_BUFLEN;
	471
	472	err= adns_addr2text(sa, 0, buf, &len, 0);
	473	if (err == EIO)
	474	err= adns_addr2text(sa, adns_qf_addrlit_scope_numeric, buf, &len, 0);
	475	assert(!err);
	476	return buf;
	477	}
51cb3de3 MW	478
	479	/*
	480	* Reverse-domain parsing and construction.
	481	*/
	482
	483	int adns__make_reverse_domain(const struct sockaddr sa, const char zone,
	484	char **buf_io, size_t bufsz,
	485	char **buf_free_r) {
	486	size_t req;
	487	char *p;
	488	unsigned c, y;
	489	unsigned long aa;
	490	const unsigned char *ap;
	491	int i, j;
	492
e0fc85c4 IJ	493	AF_IN_IN6_OTHER(sa->sa_family, {
	494	req= 4 * 4;
	495	if (!zone) zone= "in-addr.arpa";
	496	}, {
	497	req = 2 * 32;
	498	if (!zone) zone= "ip6.arpa";
	499	}, {
	500	return ENOSYS;
	501	});
51cb3de3 MW	502
	503	req += strlen(zone) + 1;
	504	if (req <= bufsz)
	505	p= *buf_io;
	506	else {
	507	p= malloc(req); if (!p) return errno;
	508	*buf_free_r = p;
	509	}
	510
	511	*buf_io= p;
e0fc85c4 IJ	512	SOCKADDR_IN_IN6(const, sa, sin, {
	513	aa= ntohl(sin->sin_addr.s_addr);
	514	for (i=0; i<4; i++) {
	515	p += sprintf(p, "%d", (int)(aa & 0xff));
51cb3de3	516	*p++= '.';
e0fc85c4	517	aa >>= 8;
51cb3de3	518	}
e0fc85c4 IJ	519	}, {
	520	ap= sin6->sin6_addr.s6_addr + 16;
	521	for (i=0; i<16; i++) {
	522	c= *--ap;
	523	for (j=0; j<2; j++) {
	524	y= c & 0xf;
	525	*p++= (y < 10) ? y + '0' : y - 10 + 'a';
	526	c >>= 4;
	527	*p++= '.';
	528	}
	529	}
	530	});
51cb3de3 MW	531
	532	strcpy(p, zone);
	533	return 0;
	534	}
	535
	536
c0af047b IJ	537	#define REVPARSE_P_L(labnum) \
	538	const char *p= dgram + rps->labstart[labnum]; \
	539	int l= rps->lablen[labnum]
	540	/*
	541	* REVPARSE_P_L(int labnum);
	542	* expects:
	543	* const char *dgram;
	544	* const struct revparse_state *rps;
	545	* produces:
	546	* const char *p; // start of label labnum in dgram
	547	* int l; // length of label in dgram
	548	*/
	549
	550	static bool revparse_check_tail(struct revparse_state *rps,
	551	const char *dgram, int nlabels,
	552	int bodylen, const char *inarpa) {
	553	int i;
51cb3de3	554
c0af047b IJ	555	if (nlabels != bodylen+2) return 0;
	556	for (i=0; i<2; i++) {
	557	REVPARSE_P_L(bodylen+i);
	558	const char *want= !i ? inarpa : "arpa";
	559	if (!adns__labels_equal(p,l, want,strlen(want))) return 0;
51cb3de3	560	}
c0af047b	561	return 1;
51cb3de3 MW	562	}
51cb3de3 MW	563
c0af047b IJ	564	static bool revparse_atoi(const char *p, int l, int base,
	565	unsigned max, unsigned *v_r) {
	566	if (l>3) return 0;
	567	if (l>1 && p[0]=='0') return 0;
	568	unsigned v=0;
	569	while (l-- > 0) {
	570	int tv;
	571	int c= ctype_toupper(*p++);
	572	if ('0'<=c && c<='9') tv = c-'0';
	573	else if ('A'<=c && c<='Z') tv = c-'A'+10;
	574	else return 0;
	575	if (tv >= base) return 0;
	576	v *= base;
	577	v += tv;
	578	}
	579	if (v>max) return 0;
	580	*v_r= v;
	581	return 1;
51cb3de3 MW	582	}
51cb3de3 MW	583
c0af047b IJ	584	static bool revparse_inet(struct revparse_state *rps,
	585	const char *dgram, int nlabels,
	586	adns_rrtype rrtype_r, adns_sockaddr addr_r) {
	587	if (!revparse_check_tail(rps,dgram,nlabels,4,"in-addr")) return 0;
51cb3de3	588
c0af047b	589	uint32_t a=0;
51cb3de3	590	int i;
c0af047b IJ	591	for (i=3; i>=0; i--) {
	592	REVPARSE_P_L(i);
	593	unsigned v;
	594	if (!revparse_atoi(p,l,10,255,&v)) return 0;
	595	a <<= 8;
	596	a \|= v;
	597	}
	598	*rrtype_r= adns_r_a;
	599	addr_r->inet.sin_family= AF_INET;
	600	addr_r->inet.sin_addr.s_addr= htonl(a);
	601	return 1;
51cb3de3 MW	602	}
51cb3de3 MW	603
c0af047b IJ	604	static bool revparse_inet6(struct revparse_state *rps,
	605	const char *dgram, int nlabels,
	606	adns_rrtype rrtype_r, adns_sockaddr addr_r) {
	607	if (!revparse_check_tail(rps,dgram,nlabels,32,"ip6")) return 0;
51cb3de3	608
c0af047b IJ	609	int i, j;
	610	memset(addr_r,0,sizeof(*addr_r));
	611	unsigned char *a= addr_r->inet6.sin6_addr.s6_addr+16;
	612	for (i=0; i<32; ) { /* i incremented in inner loop */
	613	unsigned b=0;
	614	for (j=0; j<2; j++, i++) {
	615	REVPARSE_P_L(i);
	616	unsigned v;
	617	if (!revparse_atoi(p,l,16,15,&v)) return 0;
	618	b >>= 4;
	619	b \|= v << 4;
	620	}
	621	*--a= b;
	622	}
	623	*rrtype_r= adns_r_aaaa;
	624	addr_r->inet.sin_family= AF_INET6;
	625	return 1;
	626	}
51cb3de3	627
e9fe1bdb IJ	628	bool adns__revparse_label(struct revparse_state *rps, int labnum,
e9fe1bdb IJ	629	const char *dgram, int labstart, int lablen) {
c0af047b IJ	630	if (labnum >= MAXREVLABELS)
c0af047b IJ	631	return 0;
51cb3de3	632
c0af047b IJ	633	assert(labstart <= 65535);
	634	assert(lablen <= 255);
	635	rps->labstart[labnum] = labstart;
	636	rps->lablen[labnum] = lablen;
e9fe1bdb	637	return 1;
51cb3de3 MW	638	}
51cb3de3 MW	639
e9fe1bdb IJ	640	bool adns__revparse_done(struct revparse_state *rps,
	641	const char *dgram, int nlabels,
	642	adns_rrtype rrtype_r, adns_sockaddr addr_r) {
c0af047b IJ	643	return
	644	revparse_inet(rps,dgram,nlabels,rrtype_r,addr_r) \|\|
	645	revparse_inet6(rps,dgram,nlabels,rrtype_r,addr_r);
51cb3de3	646	}