Commit 17fde12f authored by Steinar H. Gunderson's avatar Steinar H. Gunderson
Browse files

Return TTL data from ares_parse_{a,aaaa}_reply, if the user is so inclined.... 

Return TTL data from ares_parse_{a,aaaa}_reply, if the user is so inclined. Patch from the Google tree.
parent 5c8b973d

ares/ares.h

+21 −2
Original line number Diff line number Diff line
@@ -240,10 +240,29 @@ int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf, 
                     int alen, char **s, long *enclen);

int ares_expand_string(const unsigned char *encoded, const unsigned char *abuf,

                     int alen, unsigned char **s, long *enclen);



struct addrttl {

  struct in_addr ipaddr;

  int            ttl;

};

struct addr6ttl {

  struct in6_addr ip6addr;

  int             ttl;

};



/*

** Parse the buffer, starting at *abuf and of length alen bytes, previously

** obtained from an ares_search call.  Put the results in *host, if nonnull.

** Also, if addrttls is nonnull, put up to *naddrttls IPv4 addresses along with

** their TTLs in that array, and set *naddrttls to the number of addresses

** so written.

*/

int ares_parse_a_reply(const unsigned char *abuf, int alen,

                       struct hostent **host);

                       struct hostent **host,

                       struct addrttl *addrttls, int *naddrttls);

int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,

                       struct hostent **host);

                       struct hostent **host,

                       struct addr6ttl *addrttls, int *naddrttls);

int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,

                         int addrlen, int family, struct hostent **host);

int ares_parse_ns_reply(const unsigned char *abuf, int alen,

ares/ares_gethostbyname.c

+2 −2
Original line number Diff line number Diff line
@@ -160,13 +160,13 @@ static void host_callback(void *arg, int status, int timeouts, 
    {

      if (hquery->family == AF_INET)

        {

          status = ares_parse_a_reply(abuf, alen, &host);

          status = ares_parse_a_reply(abuf, alen, &host, NULL, NULL);

          if (host && channel->nsort)

            sort_addresses(host, channel->sortlist, channel->nsort);

        }

      else if (hquery->family == AF_INET6)

        {

          status = ares_parse_aaaa_reply(abuf, alen, &host);

          status = ares_parse_aaaa_reply(abuf, alen, &host, NULL, NULL);

          if (host && channel->nsort)

            sort6_addresses(host, channel->sortlist, channel->nsort);

        }

ares/ares_parse_a_reply.3

+18 −3
Original line number Diff line number Diff line
@@ -22,24 +22,39 @@ ares_parse_a_reply \- Parse a reply to a DNS query of type A into a hostent 
.B #include <ares.h>

.PP

.B int ares_parse_a_reply(const unsigned char *\fIabuf\fP, int \fIalen\fP,

.B 	struct hostent **\fIhost\fP);

.B 	struct hostent **\fIhost\fP,

.B      struct addrttl *\fIaddrttls\fB, int *\fInaddrttls\fB);

.fi

.SH DESCRIPTION

The

.B ares_parse_a_reply

function parses the response to a query of type A into a

.BR "struct hostent" .

.BR "struct hostent"

and/or an array of

.BR "struct addrttls" . 

The parameters

.I abuf

and

.I alen

give the contents of the response.  The result is stored in allocated

memory and a pointer to it stored into the variable pointed to by

.IR host .

.IR host ,

if host is nonnull.

It is the caller's responsibility to free the resulting host structure

using

.BR ares_free_hostent (3)

when it is no longer needed.

.PP

If

.IR addrttls

and

.IR naddrttls

are both nonnull,

then up to *naddrttls

.BR "struct addrttl"

records are stored in the array pointed to by addrttls,

and then *naddrttls is set to the number of records so stored.

Note that the memory for these records is supplied by the caller.

.SH RETURN VALUES

.B ares_parse_a_reply

can return any of the following values:

ares/ares_parse_a_reply.c

+98 −36
Original line number Diff line number Diff line
@@ -37,19 +37,26 @@ 
#include "ares_private.h"



int ares_parse_a_reply(const unsigned char *abuf, int alen,

                       struct hostent **host)

                       struct hostent **host,

                       struct addrttl *addrttls, int *naddrttls)

{

  unsigned int qdcount, ancount;

  int status, i, rr_type, rr_class, rr_len, naddrs;

  int status, i, rr_type, rr_class, rr_len, rr_ttl, naddrs;

  int cname_ttl = INT_MAX;  /* the TTL imposed by the CNAME chain */

  int naliases;

  long len;

  const unsigned char *aptr;

  char *hostname, *rr_name, *rr_data, **aliases;

  struct in_addr *addrs;

  struct hostent *hostent;

  const int max_addr_ttls = (addrttls && naddrttls) ? *naddrttls : 0;



  /* Set *host to NULL for all failure cases. */

  if (host)

    *host = NULL;

  /* Same with *naddrttls. */

  if (naddrttls)

    *naddrttls = 0;



  /* Give up if abuf doesn't have room for a header. */

  if (alen < HFIXEDSZ)
@@ -73,6 +80,8 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen, 
    }

  aptr += len + QFIXEDSZ;



  if (host)

    {

      /* Allocate addresses and aliases; ancount gives an upper bound for both. */

      addrs = malloc(ancount * sizeof(struct in_addr));

      if (!addrs)
@@ -87,6 +96,13 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen, 
          free(addrs);

          return ARES_ENOMEM;

        }

    }

  else

    {

      addrs = NULL;

      aliases = NULL;

    }

  

  naddrs = 0;

  naliases = 0;
@@ -106,13 +122,33 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen, 
      rr_type = DNS_RR_TYPE(aptr);

      rr_class = DNS_RR_CLASS(aptr);

      rr_len = DNS_RR_LEN(aptr);

      rr_ttl = DNS_RR_TTL(aptr);

      aptr += RRFIXEDSZ;



      if (rr_class == C_IN && rr_type == T_A

          && rr_len == sizeof(struct in_addr)

          && strcasecmp(rr_name, hostname) == 0)

        {

          if (addrs)

            {

              if (aptr + sizeof(struct in_addr) > abuf + alen)

              {

                status = ARES_EBADRESP;

                break;

              }

              memcpy(&addrs[naddrs], aptr, sizeof(struct in_addr));

            }

          if (naddrs < max_addr_ttls)

            {

              struct addrttl * const at = &addrttls[naddrs];

              if (aptr + sizeof(struct in_addr) > abuf + alen)

              {

                status = ARES_EBADRESP;

                break;

              }

              memcpy(&at->ipaddr, aptr,  sizeof(struct in_addr));

              at->ttl = rr_ttl;

            }

          naddrs++;

          status = ARES_SUCCESS;

        }
@@ -120,7 +156,10 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen, 
      if (rr_class == C_IN && rr_type == T_CNAME)

        {

          /* Record the RR name as an alias. */

          if (aliases)

            aliases[naliases] = rr_name;

          else

            free(rr_name);

          naliases++;



          /* Decode the RR data and replace the hostname with it. */
@@ -129,6 +168,10 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen, 
            break;

          free(hostname);

          hostname = rr_data;



          /* Take the min of the TTLs we see in the CNAME chain. */

          if (cname_ttl > rr_ttl)

            cname_ttl = rr_ttl;

        }

      else

        free(rr_name);
@@ -145,8 +188,23 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen, 
    status = ARES_ENODATA;

  if (status == ARES_SUCCESS)

    {

      /* We got our answer.  Allocate memory to build the host entry. */

      /* We got our answer. */

      if (naddrttls)

        {

          const int n = naddrs < max_addr_ttls ? naddrs : max_addr_ttls;

          for (i = 0; i < n; i++)

            {

              /* Ensure that each A TTL is no larger than the CNAME TTL. */

              if (addrttls[i].ttl > cname_ttl)

                addrttls[i].ttl = cname_ttl;

            }

          *naddrttls = n;

        }

      if (aliases)

        aliases[naliases] = NULL;

      if (host)

        {

          /* Allocate memory to build the host entry. */

          hostent = malloc(sizeof(struct hostent));

          if (hostent)

            {
@@ -168,9 +226,13 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen, 
            }

          status = ARES_ENOMEM;

        }

     }

  if (aliases)

    {

      for (i = 0; i < naliases; i++)

        free(aliases[i]);

      free(aliases);

    }

  free(addrs);

  free(hostname);

  return status;

ares/ares_parse_aaaa_reply.3

+18 −3
Original line number Diff line number Diff line
@@ -22,24 +22,39 @@ ares_parse_aaaa_reply \- Parse a reply to a DNS query of type AAAA into a hosten 
.B #include <ares.h>

.PP

.B int ares_parse_aaaa_reply(const unsigned char *\fIabuf\fP, int \fIalen\fP,

.B 	struct hostent **\fIhost\fP);

.B 	struct hostent **\fIhost\fP,         

.B      struct addrttl *\fIaddrttls\fB, int *\fInaddrttls\fB);

.fi

.SH DESCRIPTION

The

.B ares_parse_aaaa_reply

function parses the response to a query of type AAAA into a

.BR "struct hostent" .

.BR "struct hostent"

and/or an array of

.BR "struct addrttls" . 

The parameters

.I abuf

and

.I alen

give the contents of the response.  The result is stored in allocated

memory and a pointer to it stored into the variable pointed to by

.IR host .

.IR host ,

if host is nonnull.

It is the caller's responsibility to free the resulting host structure

using

.BR ares_free_hostent (3)

when it is no longer needed.

.PP

If

.IR addrttls

and

.IR naddrttls

are both nonnull,

then up to *naddrttls

.BR "struct addr6ttl"

records are stored in the array pointed to by addrttls,

and then *naddrttls is set to the number of records so stored.

Note that the memory for these records is supplied by the caller.

.SH RETURN VALUES

.B ares_parse_aaaa_reply

can return any of the following values: