libio/net/res.c

/*
 * A rewrite of Darren Reeds original res.c As there is nothing
 * left of Darrens original code, this is now licensed by the hybrid group.
 * (Well, some of the function names are the same, and bits of the structs..)
 * You can use it where it is useful, free even. Buy us a beer and stuff.
 *
 * The authors takes no responsibility for any damage or loss
 * of property which results from the use of this software.
 *
 * $Id$
 *
 * July 1999 - Rewrote a bunch of stuff here. Change hostent builder code,
 *     added callbacks and reference counting of returned hostents.
 *     --Bleep (Thomas Helvey <tomh@inxpress.net>)
 *
 * This was all needlessly complicated for irc. Simplified. No more hostent
 * All we really care about is the IP -> hostname mappings. Thats all. 
 *
 * Apr 28, 2003 --cryogen and Dianora
 */

#include "stdinc.h"
#include "common.h"
#include "reslib.h"

#if (CHAR_BIT != 8)
#error this code needs to be able to address individual octets 
#endif

static PF res_readreply;

#define MAXPACKET      1024  /* rfc sez 512 but we expand names so ... */
#define RES_MAXALIASES 35    /* maximum aliases allowed */
#define RES_MAXADDRS   35    /* maximum addresses allowed */
#define AR_TTL         600   /* TTL in seconds for dns cache entries */

/* RFC 1104/1105 wasn't very helpful about what these fields
 * should be named, so for now, we'll just name them this way.
 * we probably should look at what named calls them or something.
 */
#define TYPE_SIZE         (size_t)2
#define CLASS_SIZE        (size_t)2
#define TTL_SIZE          (size_t)4
#define RDLENGTH_SIZE     (size_t)2
#define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE)

typedef enum 
{
  REQ_IDLE,  /* We're doing not much at all */
  REQ_PTR,   /* Looking up a PTR */
  REQ_A,     /* Looking up an A, possibly because AAAA failed */
#ifdef IPV6
  REQ_AAAA,  /* Looking up an AAAA */
#endif
  REQ_CNAME, /* We got a CNAME in response, we better get a real answer next */
  REQ_INT    /* ip6.arpa failed, falling back to ip6.int */
} request_state;

struct reslist 
{
  dlink_node node;
  int id;
  int sent;                /* number of requests sent */
  request_state state;     /* State the resolver machine is in */
  time_t ttl;
  char type;
  char retries;            /* retry counter */
  char sends;              /* number of sends (>1 means resent) */
  char resend;             /* send flag. 0 == dont resend */
  time_t sentat;
  time_t timeout;
  struct irc_ssaddr addr;
  char *name;
  struct DNSQuery *query;  /* query callback for this request */
};

static fde_t ResolverFileDescriptor;
static dlink_list request_list    = { NULL, NULL, 0 };

static void rem_request(struct reslist *request);
static struct reslist *make_request(struct DNSQuery *query);
static void do_query_name(struct DNSQuery *query,
                          const char* name, struct reslist *request, int);
static void do_query_number(struct DNSQuery *query,
                            const struct irc_ssaddr *,
                            struct reslist *request);
static void query_name(const char *name, int query_class, int query_type, 
                       struct reslist *request);
static int send_res_msg(const char *buf, int len, int count);
static void resend_query(struct reslist *request);
static int proc_answer(struct reslist *request, HEADER *header, char *, char *);
static struct reslist *find_id(int id);
static struct DNSReply *make_dnsreply(struct reslist *request);

extern struct irc_ssaddr irc_nsaddr_list[IRCD_MAXNS];
extern int irc_nscount;
extern char irc_domain[HOSTLEN+1];


/*
 * int
 * res_ourserver(inp)
 *      looks up "inp" in irc_nsaddr_list[]
 * returns:
 *      0  : not found
 *      >0 : found
 * author:
 *      paul vixie, 29may94
 *      revised for ircd, cryogen(stu) may03
 */
static int
res_ourserver(const struct irc_ssaddr *inp) 
{
#ifdef IPV6
  struct sockaddr_in6 *v6;
  struct sockaddr_in6 *v6in = (struct sockaddr_in6 *)inp;
#endif
  struct sockaddr_in *v4;
  struct sockaddr_in *v4in = (struct sockaddr_in *)inp; 
  int ns;

  for (ns = 0;  ns < irc_nscount;  ns++)
  {
    const struct irc_ssaddr *srv = &irc_nsaddr_list[ns];
#ifdef IPV6
    v6 = (struct sockaddr_in6 *)srv;
#endif
    v4 = (struct sockaddr_in *)srv;

    /* could probably just memcmp(srv, inp, srv.ss_len) here
     * but we'll air on the side of caution - stu
     *
     */
    switch (srv->ss.ss_family)
    {
#ifdef IPV6
      case AF_INET6:
        if (srv->ss.ss_family == inp->ss.ss_family)
          if (v6->sin6_port == v6in->sin6_port)
            if ((memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr, 
                    sizeof(struct in6_addr)) == 0) || 
                (memcmp(&v6->sin6_addr.s6_addr, &in6addr_any, 
                        sizeof(struct in6_addr)) == 0))
              return(1);
        break;
#endif
      case AF_INET:
        if (srv->ss.ss_family == inp->ss.ss_family)
          if (v4->sin_port == v4in->sin_port)
            if ((v4->sin_addr.s_addr == INADDR_ANY) || 
                (v4->sin_addr.s_addr == v4in->sin_addr.s_addr))
              return(1);
        break;
      default:
        break;
    }
  }

  return(0);
}

/*
 * timeout_query_list - Remove queries from the list which have been 
 * there too long without being resolved.
 */
static time_t
timeout_query_list(time_t now)
{
  dlink_node *ptr;
  dlink_node *next_ptr;
  struct reslist *request;
  time_t next_time = 0;
  time_t timeout   = 0;

  DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head)
  {
    request = ptr->data;
    timeout = request->sentat + request->timeout;

    if (now >= timeout)
    {
      if (--request->retries <= 0)
      {
        (*request->query->callback)(request->query->ptr, NULL);
        rem_request(request);
        continue;
      }
      else
      {
        request->sentat = now;
        request->timeout += request->timeout;
        resend_query(request);
      }
    }

    if ((next_time == 0) || timeout < next_time)
    {
      next_time = timeout;
    }
  }

  return((next_time > now) ? next_time : (now + AR_TTL));
}

/*
 * timeout_resolver - check request list
 */
static void
timeout_resolver(void *notused)
{
  timeout_query_list(CurrentTime);
}

/*
 * start_resolver - do everything we need to read the resolv.conf file
 * and initialize the resolver file descriptor if needed
 */
static void
start_resolver(void)
{
  irc_res_init();

  if (!ResolverFileDescriptor.flags.open)
  {
    if (comm_open(&ResolverFileDescriptor, irc_nsaddr_list[0].ss.ss_family,
                  SOCK_DGRAM, 0, "Resolver socket") == -1)
      return;

    /* At the moment, the resolver FD data is global .. */
    comm_setselect(&ResolverFileDescriptor, COMM_SELECT_READ,
        res_readreply, NULL, 0);
    eventAdd("timeout_resolver", timeout_resolver, NULL, 1);
  }
}

/*
 * init_resolver - initialize resolver and resolver library
 */
void
init_resolver(void)
{
#ifdef HAVE_SRAND48
  srand48(CurrentTime);
#endif
  memset(&ResolverFileDescriptor, 0, sizeof(fde_t));
  start_resolver();
}

/*
 * restart_resolver - reread resolv.conf, reopen socket
 */
void
restart_resolver(void)
{
  fd_close(&ResolverFileDescriptor);
  eventDelete(timeout_resolver, NULL); /* -ddosen */
  start_resolver();
}

/*
 * add_local_domain - Add the domain to hostname, if it is missing
 * (as suggested by eps@TOASTER.SFSU.EDU)
 */
void
add_local_domain(char *hname, size_t size)
{
  /* try to fix up unqualified names 
   */
  if (strchr(hname, '.') == NULL)
  {
    if (irc_domain[0])
    {
      size_t len = strlen(hname);

      if ((strlen(irc_domain) + len + 2) < size)
      {
        hname[len++] = '.';
        strcpy(hname + len, irc_domain);
      }
    }
  }
}

/*
 * rem_request - remove a request from the list. 
 * This must also free any memory that has been allocated for 
 * temporary storage of DNS results.
 */
static void
rem_request(struct reslist *request)
{
  dlinkDelete(&request->node, &request_list);
  MyFree(request->name);
  MyFree(request);
}

/*
 * make_request - Create a DNS request record for the server.
 */
static struct reslist *
make_request(struct DNSQuery* query)
{
  struct reslist *request;

  request = (struct reslist *)MyMalloc(sizeof(struct reslist));
  memset(request, 0, sizeof(struct reslist));

  request->sentat  = CurrentTime;
  request->retries = 3;
  request->resend  = 1;
  request->timeout = 4;    /* start at 4 and exponential inc. */
  memset(&request->addr, 0, sizeof(request->addr));
  request->query   = query;
  request->state   = REQ_IDLE;

  dlinkAdd(request, &request->node, &request_list);
  return(request);
}

/*
 * delete_resolver_queries - cleanup outstanding queries 
 * for which there no longer exist clients or conf lines.
 */
void
delete_resolver_queries(const struct DNSQuery *query)
{
  dlink_node *ptr;
  dlink_node *next_ptr;
  struct reslist *request;

  DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head)
  {
    if ((request = ptr->data) != NULL)
    {
      if (query == request->query)
        rem_request(request);
    }
  }
}

/*
 * send_res_msg - sends msg to all nameservers found in the "_res" structure.
 * This should reflect /etc/resolv.conf. We will get responses
 * which arent needed but is easier than checking to see if nameserver
 * isnt present. Returns number of messages successfully sent to 
 * nameservers or -1 if no successful sends.
 */
static int
send_res_msg(const char *msg, int len, int rcount)
{
  int i;
  int sent = 0;
  int max_queries = IRCD_MIN(irc_nscount, rcount);

  /* RES_PRIMARY option is not implemented
   * if (res.options & RES_PRIMARY || 0 == max_queries)
   */
  if (max_queries == 0)
    max_queries = 1;

  for (i = 0; i < max_queries; i++)
  {
    if (sendto(ResolverFileDescriptor.fd, msg, len, 0, 
        (struct sockaddr*)&(irc_nsaddr_list[i]), 
        irc_nsaddr_list[i].ss_len) == len) 
      ++sent;
  }

  return(sent);
}

/*
 * find_id - find a dns request id (id is determined by dn_mkquery)
 */
static struct reslist *
find_id(int id)
{
  dlink_node *ptr;
  struct reslist *request;

  DLINK_FOREACH(ptr, request_list.head)
  {
    request = ptr->data;

    if (request->id == id)
      return(request);
  }

  return(NULL);
}

/* 
 * gethost_byname_type - get host address from name
 *
 */
void
gethost_byname_type(const char *name, struct DNSQuery *query, int type)
{
  assert(name != 0);
  do_query_name(query, name, NULL, type);
}

/*
 * gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported
 */
void
gethost_byname(const char *name, struct DNSQuery *query)
{
#ifdef IPV6
  gethost_byname_type(name, query, T_AAAA);
#else
  gethost_byname_type(name, query, T_A);
#endif
}

/*
 * gethost_byaddr - get host name from address
 */
void
gethost_byaddr(const struct irc_ssaddr *addr, struct DNSQuery *query)
{
  do_query_number(query, addr, NULL);
}

/*
 * do_query_name - nameserver lookup name
 */
static void
do_query_name(struct DNSQuery *query, const char *name,
              struct reslist *request, int type)
{
  char host_name[HOSTLEN + 1];

  strlcpy(host_name, name, HOSTLEN);
  add_local_domain(host_name, HOSTLEN);

  if (request == NULL)
  {
    request       = make_request(query);
    request->name = (char *)MyMalloc(strlen(host_name) + 1);
    request->type = type;
    strcpy(request->name, host_name);
#ifdef IPV6
    if (type == T_A)
      request->state = REQ_A;
    else
      request->state = REQ_AAAA;
#else
    request->state = REQ_A;
#endif
  }

  request->type = type;
  query_name(host_name, C_IN, type, request);
}

/*
 * do_query_number - Use this to do reverse IP# lookups.
 */
static void
do_query_number(struct DNSQuery *query, const struct irc_ssaddr *addr,
                struct reslist *request)
{
  char ipbuf[128];
  const unsigned char *cp;
#ifdef IPV6
  const char *intarpa;
#endif
  if (addr->ss.ss_family == AF_INET)
  {
    struct sockaddr_in *v4 = (struct sockaddr_in *)addr;
    cp = (const unsigned char*)&v4->sin_addr.s_addr;

    ircsprintf(ipbuf, "%u.%u.%u.%u.in-addr.arpa.",
               (unsigned int)(cp[3]), (unsigned int)(cp[2]),
               (unsigned int)(cp[1]), (unsigned int)(cp[0]));
  }
#ifdef IPV6
  else if (addr->ss.ss_family == AF_INET6)
  {
    struct sockaddr_in6 *v6 = (struct sockaddr_in6 *)addr;
    cp = (const unsigned char *)&v6->sin6_addr.s6_addr;

    if (request != NULL && request->state == REQ_INT)
      intarpa = "int";
    else
      intarpa = "arpa";

    (void)sprintf(ipbuf, "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x."
                  "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.%s.",
                  (unsigned int)(cp[15]&0xf), (unsigned int)(cp[15]>>4),
                  (unsigned int)(cp[14]&0xf), (unsigned int)(cp[14]>>4),
                  (unsigned int)(cp[13]&0xf), (unsigned int)(cp[13]>>4),
                  (unsigned int)(cp[12]&0xf), (unsigned int)(cp[12]>>4),
                  (unsigned int)(cp[11]&0xf), (unsigned int)(cp[11]>>4),
                  (unsigned int)(cp[10]&0xf), (unsigned int)(cp[10]>>4),
                  (unsigned int)(cp[9]&0xf), (unsigned int)(cp[9]>>4),
                  (unsigned int)(cp[8]&0xf), (unsigned int)(cp[8]>>4),
                  (unsigned int)(cp[7]&0xf), (unsigned int)(cp[7]>>4),
                  (unsigned int)(cp[6]&0xf), (unsigned int)(cp[6]>>4),
                  (unsigned int)(cp[5]&0xf), (unsigned int)(cp[5]>>4),
                  (unsigned int)(cp[4]&0xf), (unsigned int)(cp[4]>>4),
                  (unsigned int)(cp[3]&0xf), (unsigned int)(cp[3]>>4),
                  (unsigned int)(cp[2]&0xf), (unsigned int)(cp[2]>>4),
                  (unsigned int)(cp[1]&0xf), (unsigned int)(cp[1]>>4),
                  (unsigned int)(cp[0]&0xf), (unsigned int)(cp[0]>>4), intarpa);
  }
#endif
  if (request == NULL)
  {
    request       = make_request(query);
    request->type = T_PTR;
    memcpy(&request->addr, addr, sizeof(struct irc_ssaddr));
    request->name = (char *)MyMalloc(HOSTLEN + 1);
  }

  query_name(ipbuf, C_IN, T_PTR, request);
}

/*
 * query_name - generate a query based on class, type and name.
 */
static void
query_name(const char *name, int query_class, int type,
           struct reslist *request)
{
  char buf[MAXPACKET];
  int request_len = 0;

  memset(buf, 0, sizeof(buf));

  if ((request_len = irc_res_mkquery(name, query_class, type, 
      (unsigned char *)buf, sizeof(buf))) > 0)
  {
    HEADER *header = (HEADER *)buf;
#ifndef HAVE_LRAND48
    int k = 0;
    struct timeval tv;
#endif
    /*
     * generate an unique id
     * NOTE: we don't have to worry about converting this to and from
     * network byte order, the nameserver does not interpret this value
     * and returns it unchanged
     */
#ifdef HAVE_LRAND48
    do
    {
      header->id = (header->id + lrand48()) & 0xffff;
    } while (find_id(header->id));
#else
    gettimeofday(&tv, NULL);
    do
    {
      header->id = (header->id + k + tv.tv_usec) & 0xffff;
      k++;
    } while (find_id(header->id));
#endif /* HAVE_LRAND48 */
    request->id = header->id;
    ++request->sends;

    request->sent += send_res_msg(buf, request_len, request->sends);
  }
}

static void
resend_query(struct reslist *request)
{
  if (request->resend == 0)
    return;

  switch(request->type)
  {
    case T_PTR:
      do_query_number(NULL, &request->addr, request);
      break;
    case T_A:
      do_query_name(NULL, request->name, request, request->type);
      break;
#ifdef IPV6
    case T_AAAA:
      /* didnt work, try A */
      if (request->state == REQ_AAAA)
        do_query_name(NULL, request->name, request, T_A);
#endif
    default:
      break;
  }
}

/*
 * proc_answer - process name server reply
 */
static int
proc_answer(struct reslist *request, HEADER* header, char* buf, char* eob)
{
  char hostbuf[HOSTLEN + 100]; /* working buffer */
  unsigned char *current;      /* current position in buf */
  int query_class;             /* answer class */
  int type;                    /* answer type */
  int n;                       /* temp count */
  int rd_length;
  struct sockaddr_in *v4;      /* conversion */
#ifdef IPV6
  struct sockaddr_in6 *v6;
#endif
  current = (unsigned char *)buf + sizeof(HEADER);

  for (; header->qdcount > 0; --header->qdcount)
  {
    if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0)
      break;

    current += (size_t) n + QFIXEDSZ;
  }

  /*
   * process each answer sent to us blech.
   */
  while (header->ancount > 0 && (char *)current < eob)
  {
    header->ancount--;

    n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current,
        hostbuf, sizeof(hostbuf));

    if (n < 0)
    {
      /*
       * broken message
       */
      return(0);
    }
    else if (n == 0)
    {
      /*
       * no more answers left
       */
      return(0);
    }

    hostbuf[HOSTLEN] = '\0';

    /* With Address arithmetic you have to be very anal
     * this code was not working on alpha due to that
     * (spotted by rodder/jailbird/dianora)
     */
    current += (size_t) n;

    if (!(((char *)current + ANSWER_FIXED_SIZE) < eob))
      break;

    type = irc_ns_get16(current);
    current += TYPE_SIZE;

    query_class = irc_ns_get16(current);
    current += CLASS_SIZE;

    request->ttl = irc_ns_get32(current);
    current += TTL_SIZE;

    rd_length = irc_ns_get16(current);
    current += RDLENGTH_SIZE;

    /* 
     * Wait to set request->type until we verify this structure 
     */
    switch (type)
    {
      case T_A:
        if (request->type != T_A)
          return(0);

        /*
         * check for invalid rd_length or too many addresses
         */
        if (rd_length != sizeof(struct in_addr))
          return(0);
        v4 = (struct sockaddr_in *)&request->addr;
        request->addr.ss_len = sizeof(struct sockaddr_in);
        v4->sin_family = AF_INET;
        memcpy(&v4->sin_addr, current, sizeof(struct in_addr));
        return(1);
        break;
#ifdef IPV6
      case T_AAAA:
        if (request->type != T_AAAA)
          return(0);
        if (rd_length != sizeof(struct in6_addr))
          return(0);
        request->addr.ss_len = sizeof(struct sockaddr_in6);
        v6 = (struct sockaddr_in6 *)&request->addr;
        v6->sin6_family = AF_INET6;
        memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr));
        return(1);
        break;
#endif
      case T_PTR:
        if (request->type != T_PTR)
          return(0);
        n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
            current, hostbuf, sizeof(hostbuf));
        if (n < 0)
          return(0); /* broken message */
        else if (n == 0)
          return(0); /* no more answers left */

        strlcpy(request->name, hostbuf, HOSTLEN);

        return(1);
        break;
      case T_CNAME: /* first check we already havent started looking 
                       into a cname */
        if (request->type != T_PTR) 
          return(0);

        if (request->state == REQ_CNAME)
        {
          n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
                            current, hostbuf, sizeof(hostbuf));

          if (n < 0)
            return(0);
          return(1);
        }

        request->state = REQ_CNAME;
        current += rd_length;
        break;
        
      default:
        /* XXX I'd rather just throw away the entire bogus thing
         * but its possible its just a broken nameserver with still
         * valid answers. But lets do some rudimentary logging for now...
         */
        ilog(L_ERROR, "irc_res.c bogus type %d", type);
        break;
    }
  }

  return(1);
}

/*
 * res_readreply - read a dns reply from the nameserver and process it.
 */
static void
res_readreply(fde_t *fd, void *data)
{
  char buf[sizeof(HEADER) + MAXPACKET];
  HEADER *header;
  struct reslist *request = NULL;
  struct DNSReply *reply  = NULL;
  int rc;
  int answer_count;
  socklen_t len = sizeof(struct irc_ssaddr);
  struct irc_ssaddr lsin;

  rc = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len);

  /* Re-schedule a read *after* recvfrom, or we'll be registering
   * interest where it'll instantly be ready for read :-) -- adrian
   */
  comm_setselect(fd, COMM_SELECT_READ, res_readreply, NULL, 0);
  /* Better to cast the sizeof instead of rc */
  if (rc <= (int)(sizeof(HEADER)))
    return;

  /*
   * convert DNS reply reader from Network byte order to CPU byte order.
   */
  header = (HEADER *)buf;
  header->ancount = ntohs(header->ancount);
  header->qdcount = ntohs(header->qdcount);
  header->nscount = ntohs(header->nscount);
  header->arcount = ntohs(header->arcount);

  /*
   * response for an id which we have already received an answer for
   * just ignore this response.
   */
  if (0 == (request = find_id(header->id)))
    return;

  /*
   * check against possibly fake replies
   */
  if (!res_ourserver(&lsin))
    return;

  if ((header->rcode != NO_ERRORS) || (header->ancount == 0))
  {
    if (SERVFAIL == header->rcode)
    {
      /*
       * If a bad error was returned, we stop here and dont send
       * send any more (no retries granted).
       */
      (*request->query->callback)(request->query->ptr, NULL);
      rem_request(request);
    } 
    else
    {
      /* 
       * If we havent already tried this, and we're looking up AAAA, try A
       * now
       */

#ifdef IPV6
      if (request->state == REQ_AAAA && request->type == T_AAAA)
      {
        request->timeout += 4;
        resend_query(request);
      }
      else if (request->type == T_PTR && request->state != REQ_INT &&
               request->addr.ss.ss_family == AF_INET6)
      {
        request->state = REQ_INT;
        request->timeout += 4;
        request->retries--;
        resend_query(request);
      }
#endif
    }

    return;
  }
  /*
   * If this fails there was an error decoding the received packet, 
   * try it again and hope it works the next time.
   */
  answer_count = proc_answer(request, header, buf, buf + rc);

  if (answer_count)
  {
    if (request->type == T_PTR)
    {
      if (request->name == NULL)
      {
        /*
         * got a PTR response with no name, something bogus is happening
         * don't bother trying again, the client address doesn't resolve
         */
        (*request->query->callback)(request->query->ptr, reply);
        rem_request(request);
        return;
      }

      /*
       * Lookup the 'authoritative' name that we were given for the
       * ip#. 
       *
       */
#ifdef IPV6
      if (request->addr.ss.ss_family == AF_INET6)
        gethost_byname_type(request->name, request->query, T_AAAA);
      else
#endif
      gethost_byname_type(request->name, request->query, T_A);
      rem_request(request);
    }
    else
    {
      /*
       * got a name and address response, client resolved
       */
      reply = make_dnsreply(request);
      (*request->query->callback)(request->query->ptr, reply);
      MyFree(reply);
      rem_request(request);
    }
  }
  else if (!request->sent)
  {
    /* XXX - we got a response for a query we didn't send with a valid id?
     * this should never happen, bail here and leave the client unresolved
     */
    assert(0);

    /* XXX don't leak it */
    rem_request(request);
  }
}

static struct DNSReply *
make_dnsreply(struct reslist *request)
{
  struct DNSReply *cp;
  assert(request != 0);

  cp = (struct DNSReply *)MyMalloc(sizeof(struct DNSReply));

  cp->h_name = request->name;
  memcpy(&cp->addr, &request->addr, sizeof(cp->addr));
  return(cp);
}
Revision:	152
Committed:	Mon Oct 17 01:48:08 2005 UTC (20 years, 9 months ago) by db
Content type:	text/x-csrc
File size:	23571 byte(s)
Log Message:	- res.c would send out hundreds? of retry requests on clients that did not resolve, i.e. SERVFAIL. The code was essentailly ignoring SERVFAIL hence generating request after request after request. This appears to fix this major bug. It would be a good idea to add some logging here however.