/work/open62541_15/src_generated/mdnsd/mdnsd.c

Source
#include "open62541/config.h"
/*
 * Copyright (c) 2003  Jeremie Miller <jer@jabber.org>
 * Copyright (c) 2016-2026  Joachim Wiberg <troglobit@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the copyright holders nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "mdnsd.h"
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <time.h>
#include <errno.h>
#include <ifaddrs.h>
#include <arpa/inet.h>

#define SPRIME 109    /* Size of query/publish hashes */
#define LPRIME 1009    /* Size of cache hash */

#define GC 86400                /* Brute force garbage cleanup
         * frequency, rarely needed (daily
         * default) */

/* Interval for refreshing cached local interface addresses (seconds) */
#define LOCAL_ADDR_REFRESH_INTERVAL 5

/**
 * Messy, but it's the best/simplest balance I can find at the moment
 *
 * Some internal data types, and a few hashes: querys, answers, cached,
 * and records (published, unique and shared).  Each type has different
 * semantics for processing, both for timeouts, incoming, and outgoing
 * I/O.  They inter-relate too, like records affect the querys they are
 * relevant to.  Nice things about MDNS: we only publish once (and then
 * ask asked), and only query once, then just expire records we've got
 * cached
*/

struct query {
  char *name;
  int type;
  unsigned long int nexttry;
  int tries;
  int (*answer)(mdns_answer_t *, void *);
  void *arg;
  struct query *next, *list;
};

struct unicast {
  int id;
  inet_addr_t to;
  mdns_record_t *r;
  struct unicast *next;
};

struct cached {
  struct mdns_answer rr;
  struct query *q;
  struct cached *next;
};

struct mdns_record {
  struct mdns_answer rr;
  char unique;    /* # of checks performed to ensure */
  int modified;   /* Ignore conflicts after update at runtime */
  int tries;
  void (*conflict)(char *, int, void *);
  void *arg;
  struct timeval last_sent;
  struct mdns_record *next, *list;
};

struct mdns_daemon {
  char shutdown, disco, local;
  unsigned long int expireall, checkqlist;
  struct timeval now, sleep, pause, probe, publish;
  int clazz, frame;
  struct cached *cache[LPRIME];
  struct mdns_record *published[SPRIME], *probing, *a_now, *a_pause, *a_publish;
  struct unicast *uanswers;
  struct query *queries[SPRIME], *qlist;

  sa_family_t family;   /* transport: AF_INET or AF_INET6 */
  struct in_addr addr;
  struct in6_addr addr_v6;

  /* Cached local interface snapshot to avoid getifaddrs() per packet */
  struct ifaddrs *local_ifaddrs;
  time_t local_addrs_refreshed;

  mdnsd_record_received_callback received_callback;
  void *received_callback_data;
};

static int _namehash(const char *s)
{
  const unsigned char *name = (const unsigned char *)s;
  unsigned long h = 0, g;

  while (*name) {   /* do some fancy bitwanking on the string */
    h = (h << 4) + (unsigned long)(*name++);
    if ((g = (h & 0xF0000000UL)) != 0)
      h ^= (g >> 24);
    h &= ~g;
  }

  return (int)h;
}

/* Basic linked list and hash primitives */
static struct query *_q_next(mdns_daemon_t *d, struct query *q, const char *host, int type)
{
  if (!q)
    q = d->queries[_namehash(host) % SPRIME];
  else
    q = q->next;

  for (; q != 0; q = q->next) {
    if (q->type == type && strcmp(q->name, host) == 0)
      return q;
  }

  return NULL;
}

static struct cached *_c_next(mdns_daemon_t *d, struct cached *c,const char *host, int type)
{
  if (!c)
    c = d->cache[_namehash(host) % LPRIME];
  else
    c = c->next;

  for (; c != 0; c = c->next) {
    if ((type == c->rr.type || type == QTYPE_ANY) && strcmp(c->rr.name, host) == 0)
      return c;
  }

  return NULL;
}

static mdns_record_t *_r_next(mdns_daemon_t *d, mdns_record_t *r, const char *host, int type)
{
  if (!r)
    r = d->published[_namehash(host) % SPRIME];
  else
    r = r->next;

  for (; r != NULL; r = r->next) {
    if ((type == r->rr.type || type == QTYPE_ANY) && strcmp(r->rr.name, host) == 0)
      return r;
  }

  return NULL;
}

static size_t _rr_len(mdns_answer_t *rr)
{
  size_t len = 12;    /* name is always compressed (dup of earlier), plus normal stuff */

  if (rr->rdata)
    len += rr->rdlen;
  if (rr->rdname)
    len += strlen(rr->rdname); /* worst case */
  if (rr->ip.s_addr)
    len += 4;
  if (! IN6_IS_ADDR_UNSPECIFIED(&(rr->ip6)))
    len += 16;
  if (rr->type == QTYPE_PTR)
    len += 6; /* srv record stuff */

  return len;
}

/* Compares new_ rdata with known a, painfully */
static bool _a_match(struct resource *r, mdns_answer_t *a)
{
  if (!a->name)
    return 0;
  if (strcmp(r->name, a->name) || r->type != a->type)
    return 0;

  switch (r->type) {
    case QTYPE_SRV:
      return r->known.srv.name && a->rdname && strcmp(r->known.srv.name, a->rdname) == 0
        && a->srv.port == r->known.srv.port
        && a->srv.weight == r->known.srv.weight
        && a->srv.priority == r->known.srv.priority;


    case QTYPE_PTR:
    case QTYPE_NS:
    case QTYPE_CNAME:
      return r->known.ns.name && a->rdname &&
        strcmp(r->known.ns.name, a->rdname) == 0;

    case QTYPE_A:
      return memcmp(&r->known.a.ip, &a->ip, 4) == 0;

    case QTYPE_AAAA:
      return memcmp(&r->known.aaaa.ip6, &a->ip6, 16) == 0;

    default:
      return r->rdlength == a->rdlen &&
        (r->rdlength == 0 || memcmp(r->rdata, a->rdata, r->rdlength) == 0);
  }

  return 0;
}

/* Compare time values easily */
static long _tvdiff(struct timeval old, struct timeval new_)
{
  long udiff = 0;

  if (old.tv_sec != new_.tv_sec)
    udiff = (new_.tv_sec - old.tv_sec) * 1000000;

  return (new_.tv_usec - old.tv_usec) + udiff;
}

static void _r_remove_list(mdns_record_t **list, mdns_record_t *r)
{
  mdns_record_t *tmp;

  if (*list == r) {
    *list = r->list;
    r->list = NULL;
    return;
  }

  for (tmp = *list; tmp; tmp = tmp->list) {
    if (tmp->list == r) {
      tmp->list = r->list;
      r->list = NULL;
      break;
    }
    if (tmp == tmp->list)
      break;
  }
}

static void _r_remove_lists(mdns_daemon_t *d, mdns_record_t *r, mdns_record_t **skip)
{
  if (d->probing && &d->probing != skip)
    _r_remove_list(&d->probing, r);

  if (d->a_now && &d->a_now != skip)
    _r_remove_list(&d->a_now, r);

  if (d->a_pause && &d->a_pause != skip)
    _r_remove_list(&d->a_pause, r);

  if (d->a_publish && &d->a_publish != skip)
    _r_remove_list(&d->a_publish, r);
}

/* Make sure not already on the list, then insert */
static void _r_push(mdns_record_t **list, mdns_record_t *r)
{
  mdns_record_t *cur;

  for (cur = *list; cur != 0; cur = cur->list) {
    if (cur == r)
      return;
  }

  r->list = *list;
  *list = r;
}

/* Force any r out right away, if valid */
static void _r_publish(mdns_daemon_t *d, mdns_record_t *r)
{
  r->modified = 1;

  if (r->unique && r->unique < 5)
    return;    /* Probing already */

  r->tries = 0;
  d->publish.tv_sec = d->now.tv_sec;
  d->publish.tv_usec = d->now.tv_usec;

  /* check if r already in other lists. If yes, remove it from there */
  _r_remove_lists(d, r, &d->a_publish);
  _r_push(&d->a_publish, r);
}

/* send r out asap */
static void _r_send(mdns_daemon_t *d, mdns_record_t *r)
{
  /* Being published, make sure that happens soon */
  if (r->tries < 4) {
    d->publish.tv_sec = d->now.tv_sec;
    d->publish.tv_usec = d->now.tv_usec;
    return;
  }

  /* Known unique ones can be sent asap */
  if (r->unique) {
    /* check if r already in other lists. If yes, remove it from there */
    _r_remove_lists(d, r, &d->a_now);
    _r_push(&d->a_now, r);
    return;
  }

  /* Set d->pause.tv_usec to random 20-120 msec */
  d->pause.tv_sec = d->now.tv_sec;
  d->pause.tv_usec = d->now.tv_usec + (d->now.tv_usec % 100) + 20;

  /* check if r already in other lists. If yes, remove it from there */
  _r_remove_lists(d, r, &d->a_pause);
  _r_push(&d->a_pause, r);
}

/* Create generic unicast response struct */
static void _u_push(mdns_daemon_t *d, mdns_record_t *r, int id, const inet_addr_t *to)
{
  struct unicast *u;

  u = calloc(1, sizeof(struct unicast));
  if (!u)
    return;

  u->r = r;
  u->id = id;
  u->to = *to;
  u->next = d->uanswers;
  d->uanswers = u;
}

/* Drop any pending unicast answers referring to r, which is being freed */
static void _u_remove(mdns_daemon_t *d, mdns_record_t *r)
{
  struct unicast *u = d->uanswers, *prev = NULL;

  while (u) {
    struct unicast *next = u->next;

    if (u->r == r) {
      if (prev)
        prev->next = next;
      else
        d->uanswers = next;
      free(u);
    } else {
      prev = u;
    }
    u = next;
  }
}

static void _q_reset(mdns_daemon_t *d, struct query *q)
{
  struct cached *cur = 0;

  q->nexttry = 0;
  q->tries = 0;

  while ((cur = _c_next(d, cur, q->name, q->type))) {
    if (q->nexttry == 0 || cur->rr.ttl - 7 < q->nexttry)
      q->nexttry = cur->rr.ttl - 7;
  }

  if (q->nexttry != 0 && q->nexttry < d->checkqlist)
    d->checkqlist = q->nexttry;
}

/* No more queries, update all its cached entries, remove from lists */
static void _q_done(mdns_daemon_t *d, struct query *q)
{
  struct cached *c = 0;
  struct query *cur;
  int i = _namehash(q->name) % SPRIME;

  while ((c = _c_next(d, c, q->name, q->type)))
    c->q = 0;

  if (d->qlist == q) {
    d->qlist = q->list;
  } else {
    for (cur = d->qlist; cur->list != q; cur = cur->list)
      ;
    cur->list = q->list;
  }

  if (d->queries[i] == q) {
    d->queries[i] = q->next;
  } else {
    for (cur = d->queries[i]; cur->next != q; cur = cur->next)
      ;
    cur->next = q->next;
  }

  free(q->name);
  free(q);
}

static void _free_cached(struct cached *c)
{
  if (!c)
    return;

  if (c->rr.name) {
    free(c->rr.name);
    c->rr.name = NULL;
  }
  if (c->rr.rdata) {
    free(c->rr.rdata);
    c->rr.rdata = NULL;
  }
  if (c->rr.rdname) {
    free(c->rr.rdname);
    c->rr.rdname = NULL;
  }
  free(c);
}

static void _free_record(mdns_record_t *r)
{
  if (!r)
    return;

  if (r->rr.name) {
    free(r->rr.name);
    r->rr.name = NULL;
  }
  if (r->rr.rdata) {
    free(r->rr.rdata);
    r->rr.rdata = NULL;
  }
  if (r->rr.rdname) {
    free(r->rr.rdname);
    r->rr.rdname = NULL;
  }
  free(r);
}

/* buh-bye, remove from hash and free */
static void _r_done(mdns_daemon_t *d, mdns_record_t *r)
{
  mdns_record_t *cur = 0;
  int i;

  if (!r || !r->rr.name)
    return;

  i = _namehash(r->rr.name) % SPRIME;
  if (d->published[i] == r) {
    d->published[i] = r->next;
  } else {
    for (cur = d->published[i]; cur && cur->next != r; cur = cur->next)
      ;
    if (cur)
      cur->next = r->next;
  }

  /* A queued unicast answer may still point at r; drop it first. */
  _u_remove(d, r);

  _free_record(r);
}

/* Call the answer function with this cached entry */
static void _q_answer(mdns_daemon_t *d, struct cached *c)
{
  if (c->rr.ttl <= (unsigned long)d->now.tv_sec)
    c->rr.ttl = 0;
  if (c->q->answer(&c->rr, c->q->arg) == -1)
    _q_done(d, c->q);
}

static void _conflict(mdns_daemon_t *d, mdns_record_t *r)
{
  r->conflict(r->rr.name, r->rr.type, r->arg);
  mdnsd_done(d, r);
}

/* Expire any old entries in this list */
static void _c_expire(mdns_daemon_t *d, struct cached **list)
{
  struct cached *cur  = *list;
  struct cached *last = NULL;
  struct cached *next;

  while (cur) {
    next = cur->next;

    if ((unsigned long)d->now.tv_sec >= cur->rr.ttl) {
      if (last)
        last->next = next;

      /* Update list pointer if the first one expired */
      if (*list == cur)
        *list = next;

      if (cur->q)
        _q_answer(d, cur);

      _free_cached(cur);
    } else {
      last = cur;
    }
    cur = next;
  }
}

/* Brute force expire any old cached records */
static void _gc(mdns_daemon_t *d)
{
  int i;

  for (i = 0; i < LPRIME; i++) {
    if (d->cache[i])
      _c_expire(d, &d->cache[i]);
  }

  d->expireall = (unsigned long)(d->now.tv_sec + GC);
}

static int _cache(mdns_daemon_t *d, struct resource *r, const inet_addr_t *from)
{
  unsigned long int ttl;
  struct cached *c = 0;
  int i = _namehash(r->name) % LPRIME;

  /* Cache flush for unique entries */
  if (r->clazz == 32768 + d->clazz) {
    while ((c = _c_next(d, c, r->name, r->type)))
      c->rr.ttl = 0;
    _c_expire(d, &d->cache[i]);
  }

  /* Process deletes */
  if (r->ttl == 0) {
    while ((c = _c_next(d, c, r->name, r->type))) {
      if (_a_match(r, &c->rr)) {
        c->rr.ttl = 0;
        _c_expire(d, &d->cache[i]);
        c = NULL;
      }
    }

    return 0;
  }

  /*
   * XXX: The c->rr.ttl is a hack for now, BAD SPEC, start
   *      retrying just after half-waypoint, then expire
   */
  ttl = (unsigned long)d->now.tv_sec + (r->ttl / 2) + 8;

  /*
   * If this record is already cached, just refresh its TTL.  Match on
   * the rdata, not only name+type: a host can have several A/AAAA
   * records (e.g. a link-local and a global address), each its own entry.
   */
  c = NULL;
  while ((c = _c_next(d, c, r->name, r->type))) {
    if (!_a_match(r, &c->rr))
      continue;
    c->rr.ttl = ttl;
    return 0;
  }

  /* New entry, cache it */
  c = calloc(1, sizeof(struct cached));
  if (!c)
    return 1;

  c->rr.name = strdup(r->name);
  if (!c->rr.name) {
    free(c);
    return 1;
  }
  c->rr.type = r->type;
  c->rr.ttl = ttl;
  c->rr.rdlen = r->rdlength;
  if (r->rdlength && !r->rdata) {
//    ERR("rdlength is %d but rdata is NULL for domain name %s, type: %d, ttl: %ld", r->rdlength, r->name, r->type, r->ttl);
    free(c->rr.name);
    free(c);
    return 1;
  }
  if (r->rdlength) {
    c->rr.rdata = malloc(r->rdlength);
    if (!c->rr.rdata) {
      free(c->rr.name);
      free(c);
      return 1;
    }
    memcpy(c->rr.rdata, r->rdata, r->rdlength);
  } else {
    c->rr.rdata = NULL;
  }

  switch (r->type) {
  case QTYPE_A:
    c->rr.ip = r->known.a.ip;
    break;

  case QTYPE_AAAA:
    c->rr.ip6 = r->known.aaaa.ip6;
    break;

  case QTYPE_NS:
  case QTYPE_CNAME:
  case QTYPE_PTR:
    if (!r->known.ns.name) {
      free(c->rr.rdata);
      free(c->rr.name);
      free(c);
      return 1;
    }
    c->rr.rdname = strdup(r->known.ns.name);
    /* Stash the responder address for mquery's device view */
#ifdef ENABLE_IPV6
    if (inet_family(from) == AF_INET6)
      c->rr.ip6 = ((const struct sockaddr_in6 *)from)->sin6_addr;
    else
#endif
      c->rr.ip = ((const struct sockaddr_in *)from)->sin_addr;
    break;

  case QTYPE_SRV:
    if (!r->known.srv.name) {
      free(c->rr.rdata);
      free(c->rr.name);
      free(c);
      return 1;
    }
    c->rr.rdname = strdup(r->known.srv.name);
    c->rr.srv.port = r->known.srv.port;
    c->rr.srv.weight = r->known.srv.weight;
    c->rr.srv.priority = r->known.srv.priority;
    break;
  }

  c->next = d->cache[i];
  d->cache[i] = c;

  if ((c->q = _q_next(d, 0, r->name, r->type)))
    _q_answer(d, c);

  return 0;
}

/* Copy the data bits only */
static void _a_copy(struct message *m, mdns_answer_t *a)
{
  /*
   * Re-encode name rdata from rdname so compression is computed for
   * this packet.  The raw cached rdata holds pointers into the packet
   * it arrived in and cannot be replayed verbatim.  See issue #79.
   */
  if (a->type == QTYPE_SRV) {
    message_rdata_srv(m, a->srv.priority, a->srv.weight, a->srv.port, a->rdname);
    return;
  }
  if (a->rdname) {
    message_rdata_name(m, a->rdname);
    return;
  }

  if (a->rdata) {
    message_rdata_raw(m, a->rdata, a->rdlen);
    return;
  }

  if (a->ip.s_addr)
    message_rdata_ipv4(m, a->ip);
  else if (!IN6_IS_ADDR_UNSPECIFIED(&(a->ip6)))
    message_rdata_ipv6(m, a->ip6);
}

/*
 * RFC 6763 §12: when answering a PTR or SRV query, add the related SRV,
 * TXT and address records to the additional section so a client need not
 * query again.  See issue #76.  Records answered this round are tracked so
 * we never repeat one of them as an additional record.
 */
#define ADDITIONAL_MAX 64
struct answered {
  mdns_record_t *rec[ADDITIONAL_MAX];
  int n;
};

static void _answered_add(struct answered *a, mdns_record_t *r)
{
  if (a->n < ADDITIONAL_MAX)
    a->rec[a->n++] = r;
}

static int _answered(const struct answered *a, const mdns_record_t *r)
{
  int i;

  for (i = 0; i < a->n; i++) {
    if (a->rec[i] == r)
      return 1;
  }

  return 0;
}

/* Append one additional record, unless already in the packet or out of room */
static void _ar(mdns_daemon_t *d, struct message *m, mdns_record_t *r, struct answered *seen)
{
  if (_answered(seen, r))
    return;
  if (message_packet_len(m) + (int)_rr_len(&r->rr) >= d->frame)
    return;

  message_ar(m, r->rr.name, r->rr.type, d->clazz + (r->unique ? 32768 : 0), r->rr.ttl);
  _a_copy(m, &r->rr);
  _answered_add(seen, r);
}

/* Append the A/AAAA records for host to the additional section */
static void _ar_addr(mdns_daemon_t *d, struct message *m, char *host, struct answered *seen)
{
  mdns_record_t *r;

  if (!host)
    return;

  for (r = mdnsd_get_published(d, host); r; r = r->next) {
    if (strcmp(r->rr.name, host))
      continue;
    if (r->rr.type == QTYPE_A || r->rr.type == QTYPE_AAAA)
      _ar(d, m, r, seen);
  }
}

/* RFC 6763 §12 additional records for an answered PTR or SRV record */
static void _additional(mdns_daemon_t *d, struct message *m, mdns_record_t *ans, struct answered *seen)
{
  mdns_record_t *r;

  if (ans->rr.type == QTYPE_SRV) {
    _ar_addr(d, m, ans->rr.rdname, seen);
    return;
  }

  if (ans->rr.type != QTYPE_PTR || !ans->rr.rdname || !strcmp(ans->rr.name, DISCO_NAME))
    return;

  for (r = mdnsd_get_published(d, ans->rr.rdname); r; r = r->next) {
    if (strcmp(r->rr.name, ans->rr.rdname))
      continue;

    if (r->rr.type == QTYPE_SRV) {
      _ar(d, m, r, seen);
      _ar_addr(d, m, r->rr.rdname, seen);
    } else if (r->rr.type == QTYPE_TXT) {
      _ar(d, m, r, seen);
    }
  }
}

/* Copy a published record into an outgoing message */
static int _r_out(mdns_daemon_t *d, struct message *m, mdns_record_t **list, struct answered *seen)
{
  mdns_record_t *r;
  int ret = 0;

  while ((r = *list) != NULL && message_packet_len(m) + (int)_rr_len(&r->rr) < d->frame) {
    if (r != r->list)
      *list = r->list;
    else
      *list = NULL;

    /* Service enumeration/discovery, drop non-PTR replies */
    if (d->disco) {
      if (r->rr.type != QTYPE_PTR)
        continue;

      if (strcmp(r->rr.name, DISCO_NAME))
        continue;
    }

    INFO("Appending name: %s, type %d to outbound message ...", r->rr.name, r->rr.type);
    ret++;

    if (r->unique)
      message_an(m, r->rr.name, r->rr.type, d->clazz + 32768, r->rr.ttl);
    else
      message_an(m, r->rr.name, r->rr.type, d->clazz, r->rr.ttl);
    r->last_sent = d->now;

    _a_copy(m, &r->rr);

    r->modified = 0; /* If updated we've now sent the update. */
    if (r->rr.ttl == 0) {
      /*
       * also remove from other lists, because record
       * may be in multiple lists at the same time
       */
      _r_remove_lists(d, r, list);
      _r_done(d, r);
    } else {
      _answered_add(seen, r);
    }
  }

  return ret;
}

/* Refresh the cached local interface addresses if needed (every ~5s) */
static void _refresh_local_addrs(mdns_daemon_t *d, bool force)
{
  struct ifaddrs *ifa = NULL;

  /* Refresh at most every 5 seconds */
  if (d->local_addrs_refreshed && (d->now.tv_sec - d->local_addrs_refreshed) < LOCAL_ADDR_REFRESH_INTERVAL && !force)
    return;

  if (getifaddrs(&ifa) != 0)
    return;

  /* Swap in the latest snapshot */
  if (d->local_ifaddrs)
    freeifaddrs(d->local_ifaddrs);
  d->local_ifaddrs = ifa;
  d->local_addrs_refreshed = d->now.tv_sec ? d->now.tv_sec : time(NULL);
}

/* Check if an IPv4 address belongs to this host (any interface) */
static bool _is_local_ipv4(mdns_daemon_t *d, struct in_addr ip)
{
  struct ifaddrs *it;

  /* Always consider the primary configured address as local */
  if (ip.s_addr == d->addr.s_addr)
    return true;

  _refresh_local_addrs(d, false);

  for (it = d->local_ifaddrs; it; it = it->ifa_next) {
    struct sockaddr_in *sin;
    if (!it->ifa_addr)
      continue;
    if (it->ifa_addr->sa_family != AF_INET)
      continue;
    sin = (struct sockaddr_in *)it->ifa_addr;
    if (sin->sin_addr.s_addr == ip.s_addr)
      return true;
  }

  return false;
}

#ifdef ENABLE_IPV6
/* Check if an IPv6 address belongs to this host (any interface) */
static bool _is_local_ipv6(mdns_daemon_t *d, struct in6_addr ip)
{
  struct ifaddrs *it;

  if (IN6_ARE_ADDR_EQUAL(&ip, &d->addr_v6))
    return true;

  _refresh_local_addrs(d, false);

  for (it = d->local_ifaddrs; it; it = it->ifa_next) {
    struct sockaddr_in6 *sin6;

    if (!it->ifa_addr || it->ifa_addr->sa_family != AF_INET6)
      continue;
    sin6 = (struct sockaddr_in6 *)it->ifa_addr;
    if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, &ip))
      return true;
  }

  return false;
}
#endif

/* Ignore packets we sent ourselves, regardless of address family */
static bool _is_local(mdns_daemon_t *d, const inet_addr_t *from)
{
#ifdef ENABLE_IPV6
  if (inet_family(from) == AF_INET6)
    return _is_local_ipv6(d, ((const struct sockaddr_in6 *)from)->sin6_addr);
#endif
  return _is_local_ipv4(d, ((const struct sockaddr_in *)from)->sin_addr);
}

/* mDNS multicast destination for the daemon's transport family */
static void mdns_mcast(inet_addr_t *to, sa_family_t family)
{
  memset(to, 0, sizeof(*to));
  to->ss_family = family;

#ifdef ENABLE_IPV6
  if (family == AF_INET6) {
    struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)to;

    inet_pton(AF_INET6, "ff02::fb", &sin6->sin6_addr);
    sin6->sin6_port = htons(5353);
    return;
  }
#endif
  ((struct sockaddr_in *)to)->sin_addr.s_addr = inet_addr("224.0.0.251");
  ((struct sockaddr_in *)to)->sin_port        = htons(5353);
}

mdns_daemon_t *mdnsd_new(int clazz, int frame)
{
  mdns_daemon_t *d;

  d = calloc(1, sizeof(struct mdns_daemon));
  if (!d)
    return NULL;

  gettimeofday(&d->now, 0);
  d->expireall = (unsigned long)d->now.tv_sec + GC;
  d->clazz = clazz;
  d->frame = frame;
  d->family = AF_INET;
  d->local = 1;   /* process replies from our own host by default */
  d->received_callback = NULL;
  d->local_ifaddrs = NULL;
  d->local_addrs_refreshed = 0;

  return d;
}

void mdnsd_set_family(mdns_daemon_t *d, sa_family_t family)
{
  d->family = family;
}

/* Process replies from our own host, or ignore them like avahi-browse(1) -l */
void mdnsd_set_local(mdns_daemon_t *d, int enable)
{
  d->local = enable ? 1 : 0;
}

int mdnsd_get_local(mdns_daemon_t *d)
{
  return d->local;
}

void mdnsd_set_address(mdns_daemon_t *d, struct in_addr addr)
{
  int i;

  if (!memcmp(&d->addr, &addr, sizeof(d->addr)))
    return;   /* No change */

  for (i = 0; i < SPRIME; i++) {
    mdns_record_t *r, *next;

    r = d->published[i];
    while (r) {
      next = r->next;

      if (r->rr.type == QTYPE_A) {
        if (addr.s_addr == 0) {
          r->rr.ttl = 0;
          r->list = d->a_now;
          d->a_now = r;
        } else {
          mdnsd_set_ip(d, r, addr);
        }
      }

      r = next;
    }
  }

  d->addr = addr;
}

struct in_addr mdnsd_get_address(mdns_daemon_t *d)
{
  return d->addr;
}

void mdnsd_set_ipv6_address(mdns_daemon_t *d, struct in6_addr addr)
{
  int i;

  if (!memcmp(&d->addr_v6, &addr, sizeof(d->addr_v6)))
    return;   /* No change */

  for (i = 0; i < SPRIME; i++) {
    mdns_record_t *r, *next;

    r = d->published[i];
    while (r) {
      next = r->next;

      if (r->rr.type == QTYPE_AAAA) {
        if (IN6_IS_ADDR_UNSPECIFIED(&addr)) {
          r->rr.ttl = 0;
          r->list = d->a_now;
          d->a_now = r;
        } else {
          mdnsd_set_ipv6(d, r, addr);
        }
      }

      r = next;
    }
  }

  d->addr_v6 = addr;
}

struct in6_addr mdnsd_get_ipv6_address(mdns_daemon_t *d)
{
  return d->addr_v6;
}

/* Shutting down, zero out ttl and push out all records */
void mdnsd_shutdown(mdns_daemon_t *d)
{
  int i;
  mdns_record_t *cur, *next;

  if (!d)
    return;

  d->a_now = 0;
  for (i = 0; i < SPRIME; i++) {
    for (cur = d->published[i]; cur != 0;) {
      next = cur->next;
      cur->rr.ttl = 0;
      cur->list = d->a_now;
      d->a_now = cur;
      cur = next;
    }
  }

  d->shutdown = 1;
}

void mdnsd_flush(mdns_daemon_t *d)
{
  (void)d;
  /* - Set all querys to 0 tries
   * - Free whole cache
   * - Set all mdns_record_t *to probing
   * - Reset all answer lists
   */
}

void mdnsd_free(mdns_daemon_t *d)
{
  struct unicast *u;

  if (!d)
    return;

  for (size_t i = 0; i< LPRIME; i++) {
    struct cached *cur = d->cache[i];

    while (cur) {
      struct cached *next = cur->next;

      cur->next = NULL;
      _free_cached(cur);
      cur = next;
    }
  }

  for (size_t i = 0; i< SPRIME; i++) {
    struct mdns_record *cur = d->published[i];
    struct query *curq;

    while (cur) {
      struct mdns_record *next = cur->next;

      cur->next = NULL;
      _free_record(cur);
      cur = next;
    }

    curq = d->queries[i];
    while (curq) {
      struct query *next = curq->next;

      curq->next = NULL;
      free(curq->name);
      free(curq);
      curq = next;
    }
  }

  u = d->uanswers;
  while (u) {
    struct unicast *next = u->next;

    u->next = NULL;
    free(u);
    u = next;
  }

  if (d->local_ifaddrs)
    freeifaddrs(d->local_ifaddrs);

  free(d);
}


void mdnsd_register_receive_callback(mdns_daemon_t *d, mdnsd_record_received_callback cb, void* data)
{
  d->received_callback = cb;
  d->received_callback_data = data;
}

int mdnsd_in(mdns_daemon_t *d, struct message *m, const inet_addr_t *from)
{
  mdns_record_t *r = NULL;
  int i, j;
  bool did_addr_refresh = false;

  if (d->shutdown)
    return 1;

  gettimeofday(&d->now, 0);

  /* Skip replies from our own host when local processing is off, cf. mquery -L */
  if (!d->local && _is_local(d, from))
    return 0;

  if (m->header.qr == 0) {
    /* Process each query */
    for (i = 0; i < m->qdcount; i++) {
      mdns_record_t *r_start, *r_next;
      bool has_conflict = false;

      if (!m->qd || m->qd[i].clazz != d->clazz)
        continue;

      INFO("Query for %s of type %d ...", m->qd[i].name, m->qd[i].type);
      r = _r_next(d, NULL, m->qd[i].name, m->qd[i].type);
      if (!r)
        continue;

      /* Service enumeration/discovery prepare to send all matching records */
      if (!strcmp(m->qd[i].name, DISCO_NAME)) {
        d->disco = 1;
        while (r) {
          if (!strcmp(r->rr.name, DISCO_NAME))
            _r_send(d, r);
          r = _r_next(d, r, m->qd[i].name, m->qd[i].type);
        }

        continue;
      }

      /* Check all of our potential answers */
      for (r_start = r; r != NULL; r = r_next) {
        INFO("Local record: %s, type: %d, rdname: %s", r->rr.name, r->rr.type, r->rr.rdname);

        /* Fetch next here, because _conflict() might delete r, invalidating next */
        r_next = _r_next(d, r, m->qd[i].name, m->qd[i].type);

        /* probing state, check for conflicts */
        if (r->unique && r->unique < 5 && !r->modified) {
          /* Check all to-be answers against our own */
          for (j = 0; j < m->ancount; j++) {
            if (!m->an || m->qd[i].type != m->an[j].type || strcmp(m->qd[i].name, m->an[j].name))
              continue;

            /* This answer isn't ours, conflict! */
            if (!_a_match(&m->an[j], &r->rr)) {
              /* Before flagging conflict, force a local address refresh and re-check */
              if (!did_addr_refresh) {
                did_addr_refresh = true;
                _refresh_local_addrs(d, true);
              }
              if (_is_local(d, from))
                continue;
              _conflict(d, r);
              has_conflict = true;
              break;
            }
          }
          continue;
        }

        /* Check the known answers for this question */
        for (j = 0; j < m->ancount; j++) {
          if (!m->an || m->qd[i].type != m->an[j].type || strcmp(m->qd[i].name, m->an[j].name))
            continue;

          if (d->received_callback)
            d->received_callback(&m->an[j], d->received_callback_data);

          /* Do they already have this answer? */
          if (_a_match(&m->an[j], &r->rr))
            break;
        }

        INFO("Should we send answer? j: %d, m->ancount: %d", j, m->ancount);
        if (j == m->ancount) {
          INFO("Yes we should, enquing %s for outbound", r->rr.name);
          _r_send(d, r);
        }
      }

      /* Send the matching unicast reply */
      if (!has_conflict && inet_port(from) != 5353)
        _u_push(d, r_start, m->id, from);
    }

    return 0;
  }

  /* Process each answer, check for a conflict, and cache */
  for (i = 0; i < m->ancount; i++) {
    if (!m->an)
      continue;

    if (!m->an[i].name) {
      ERR("Got answer with NULL name at %p. Type: %d, TTL: %ld, skipping",
          (void*)&m->an[i], m->an[i].type, m->an[i].ttl);
      continue;
    }

    INFO("Got Answer: Name: %s, Type: %d", m->an[i].name, m->an[i].type);
    r = _r_next(d, NULL, m->an[i].name, m->an[i].type);
    if (r && r->unique && r->modified && _a_match(&m->an[i], &r->rr)) {
      /* double check, is this actually from us, looped back? */
      if (!did_addr_refresh) {
        did_addr_refresh = true;
        _refresh_local_addrs(d, true);
      }
      if (_is_local(d, from))
        continue;
      _conflict(d, r);
    }

    if (d->received_callback)
      d->received_callback(&m->an[i], d->received_callback_data);

    if (_cache(d, &m->an[i], from) != 0) {
      ERR("Failed caching answer, possibly too long packet, skipping.");
      continue;
    }
  }

  return 0;
}

int mdnsd_out(mdns_daemon_t *d, struct message *m, inet_addr_t *to)
{
  mdns_record_t *r;
  struct answered seen = { 0 };
  int ret = 0;

  gettimeofday(&d->now, 0);
  memset(m, 0, sizeof(struct message));

  /* Defaults, multicast */
  mdns_mcast(to, d->family);
  m->header.qr = 1;
  m->header.aa = 1;

  /* Send out individual unicast answers */
  if (d->uanswers) {
    struct unicast *u = d->uanswers;

    INFO("Send Unicast Answer: Name: %s, Type: %d", u->r->rr.name, u->r->rr.type);

    d->uanswers = u->next;
    *to = u->to;
    m->id = u->id;
    message_qd(m, u->r->rr.name, u->r->rr.type, d->clazz);
    message_an(m, u->r->rr.name, u->r->rr.type, d->clazz, u->r->rr.ttl);
    u->r->last_sent = d->now;
    _a_copy(m, &u->r->rr);

    /* RFC 6763 §12 additional records for the unicast answer */
    _answered_add(&seen, u->r);
    _additional(d, m, u->r, &seen);
    free(u);

    return 1;
  }

  /* Accumulate any immediate responses */
  if (d->a_now)
    ret += _r_out(d, m, &d->a_now, &seen);

  /* Check if it's time to send the publish retries (unlink if done) */
  if (!d->probing && d->a_publish && _tvdiff(d->now, d->publish) <= 0) {
    mdns_record_t *cur = d->a_publish;
    mdns_record_t *last = NULL;
    mdns_record_t *next;

    while (cur && message_packet_len(m) + (int)_rr_len(&cur->rr) < d->frame) {
      if (cur->rr.type == QTYPE_PTR) {
        INFO("Send Publish PTR: Name: %s, rdlen: %d, rdata: %s, rdname: %s", cur->rr.name,cur->rr.rdlen, cur->rr.rdata, cur->rr.rdname);
      } else if (cur->rr.type == QTYPE_SRV) {
        INFO("Send Publish SRV: Name: %s, rdlen: %d, rdata: %s, rdname: %s, port: %d, prio: %d, weight: %d", cur->rr.name,cur->rr.rdlen, cur->rr.rdname, cur->rr.rdata, cur->rr.srv.port, cur->rr.srv.priority, cur->rr.srv.weight);
      } else {
        INFO("Send Publish: Name: %s, Type: %d, rdname: %s", cur->rr.name, cur->rr.type, cur->rr.rdname);
      }

      next = cur->list;
      ret++;
      cur->tries++;

      if (cur->unique)
        message_an(m, cur->rr.name, cur->rr.type, d->clazz + 32768, cur->rr.ttl);
      else
        message_an(m, cur->rr.name, cur->rr.type, d->clazz, cur->rr.ttl);
      _a_copy(m, &cur->rr);
      cur->last_sent = d->now;
      if (cur->rr.ttl != 0)
        _answered_add(&seen, cur);

      if (cur->rr.ttl != 0 && cur->tries < 4) {
        last = cur;
        cur = next;
        continue;
      }

      cur->list = NULL;
      if (d->a_publish == cur)
        d->a_publish = next;
      if (last)
        last->list = next;
      if (cur->rr.ttl == 0)
        _r_done(d, cur);
      cur = next;
    }

    if (d->a_publish) {
      d->publish.tv_sec = d->now.tv_sec + 2;
      d->publish.tv_usec = d->now.tv_usec;
    }
  }

  /* If we're in shutdown, we're done */
  if (d->shutdown)
    return ret;

  /* Check if a_pause is ready */
  if (d->a_pause && _tvdiff(d->now, d->pause) <= 0)
    ret += _r_out(d, m, &d->a_pause, &seen);

  /* RFC 6763 §12: expand the answers, not the additionals _ar() appends */
  for (int i = 0, n = seen.n; i < n; i++)
    _additional(d, m, seen.rec[i], &seen);

  /* Now process questions */
  if (ret)
    return ret;

  m->header.qr = 0;
  m->header.aa = 0;

  if (d->probing && _tvdiff(d->now, d->probe) <= 0) {
    mdns_record_t *last = 0;

    /* Scan probe list to ask questions and process published */
    for (r = d->probing; r != NULL;) {
      /* Done probing, publish */
      if (r->unique == 4) {
        mdns_record_t *next = r->list;

        if (d->probing == r)
          d->probing = r->list;
        else if (last)
          last->list = r->list;

        r->list = 0;
        r->unique = 5;
        _r_publish(d, r);
        r = next;
        continue;
      }

      INFO("Send Probing: Name: %s, Type: %d", r->rr.name, r->rr.type);

      message_qd(m, r->rr.name, r->rr.type, (unsigned short)d->clazz);
      r->last_sent = d->now;
      last = r;
      r = r->list;
    }

    /* Scan probe list again to append our to-be answers */
    for (r = d->probing; r != 0; r = r->list) {
      r->unique++;

      INFO("Send Answer in Probe: Name: %s, Type: %d", r->rr.name, r->rr.type);
      message_ns(m, r->rr.name, r->rr.type, (unsigned short)d->clazz, r->rr.ttl);
      _a_copy(m, &r->rr);
      r->last_sent = d->now;
      ret++;
    }

    /* Process probes again in the future */
    if (ret) {
      d->probe.tv_sec = d->now.tv_sec;
      d->probe.tv_usec = d->now.tv_usec + 250000;
      return ret;
    }
  }

  /* Process qlist for retries or expirations */
  if (d->checkqlist && (unsigned long)d->now.tv_sec >= d->checkqlist) {
    struct query *q;
    struct cached *c;
    unsigned long int nextbest = 0;

    /* Ask questions first, track nextbest time */
    for (q = d->qlist; q != 0; q = q->list) {
      if (q->nexttry > 0 && q->nexttry <= (unsigned long)d->now.tv_sec && q->tries < 3)
        message_qd(m, q->name, q->type, d->clazz);
      else if (q->nexttry > 0 && (nextbest == 0 || q->nexttry < nextbest))
        nextbest = q->nexttry;
    }

    /* Include known answers, update questions */
    for (q = d->qlist; q != 0; q = q->list) {
      if (q->nexttry == 0 || q->nexttry > (unsigned long)d->now.tv_sec)
        continue;

      /* Done retrying, expire and reset */
      if (q->tries == 3) {
        _c_expire(d, &d->cache[_namehash(q->name) % LPRIME]);
        _q_reset(d, q);
        continue;
      }

      ret++;
      q->nexttry = d->now.tv_sec + ++q->tries;
      if (nextbest == 0 || q->nexttry < nextbest)
        nextbest = q->nexttry;

      /* If room, add all known good entries */
      c = 0;
      while ((c = _c_next(d, c, q->name, q->type)) != 0 && c->rr.ttl > (unsigned long)d->now.tv_sec + 8 &&
        message_packet_len(m) + (int)_rr_len(&c->rr) < d->frame) {

        INFO("Add known answer: Name: %s, Type: %d", c->rr.name, c->rr.type);
        message_an(m, q->name, (unsigned short)q->type, (unsigned short)d->clazz, c->rr.ttl - (unsigned long)d->now.tv_sec);
        _a_copy(m, &c->rr);
      }
    }
    d->checkqlist = nextbest;
  }

  if ((unsigned long)d->now.tv_sec > d->expireall)
    _gc(d);

  return ret;
}


#define RET do {       \
  while (d->sleep.tv_usec > 1000000) { \
    d->sleep.tv_sec++;    \
    d->sleep.tv_usec -= 1000000;  \
  }          \
  return &d->sleep;     \
} while (0)

struct timeval *mdnsd_sleep(mdns_daemon_t *d)
{
  time_t expire;
  long usec;

  d->sleep.tv_sec = d->sleep.tv_usec = 0;

  /* First check for any immediate items to handle */
  if (d->uanswers || d->a_now)
    return &d->sleep;

  gettimeofday(&d->now, 0);

  /* Then check for paused answers or nearly expired records */
  if (d->a_pause) {
    if ((usec = _tvdiff(d->now, d->pause)) > 0)
      d->sleep.tv_usec = usec;
    RET;
  }

  /* Now check for probe retries */
  if (d->probing) {
    if ((usec = _tvdiff(d->now, d->probe)) > 0)
      d->sleep.tv_usec = usec;
    RET;
  }

  /* Now check for publish retries */
  if (d->a_publish) {
    if ((usec = _tvdiff(d->now, d->publish)) > 0)
      d->sleep.tv_usec = usec;
    RET;
  }

  /* Also check for queries with known answer expiration/retry */
  if (d->checkqlist) {
    long sec;
    if ((sec = (long)d->checkqlist - d->now.tv_sec) > 0)
      d->sleep.tv_sec = sec;
    RET;
  }

  /* Resend published records before TTL expires */
  expire = (long)d->expireall - d->now.tv_sec;
  if (expire < 0)
    RET;

  for (size_t i = 0; i < SPRIME; i++) {
    mdns_record_t *r;
    time_t next;

    r = d->published[i];
    if (!r)
      continue;

    /* Publish 2 seconds before expiration */
    next = r->last_sent.tv_sec + (long)r->rr.ttl - d->now.tv_sec;
    if (next <= 2) {
      INFO("Republish %s before TTL expires ...", r->rr.name);
      _r_push(&d->a_pause, r);
    }

    if (next < expire)
      expire = next;
  }

  d->sleep.tv_sec = expire > 2 ? expire - 2 : 0;
  d->pause.tv_sec = d->now.tv_sec + d->sleep.tv_sec;

  RET;
}

void mdnsd_query(mdns_daemon_t *d, const char *host, int type, int (*answer)(mdns_answer_t *a, void *arg), void *arg)
{
  struct query *q;
  struct cached *cur = 0;
  int i = _namehash(host) % SPRIME;

  if (!(q = _q_next(d, 0, host, type))) {
    if (!answer)
      return;

    q = calloc(1, sizeof(struct query));
    if (!q)
      return;
    q->name = strdup(host);
    if (!q->name) {
      free(q);
      return;
    }
    q->type = type;
    q->next = d->queries[i];
    q->list = d->qlist;
    d->qlist = d->queries[i] = q;

    /* Any cached entries should be associated */
    while ((cur = _c_next(d, cur, q->name, q->type)))
      cur->q = q;
    _q_reset(d, q);

    /* New question, immediately send out */
    q->nexttry = d->checkqlist = d->now.tv_sec;
  }

  /* No answer means we don't care anymore */
  if (!answer) {
    _q_done(d, q);
    return;
  }

  q->answer = answer;
  q->arg = arg;
}

mdns_answer_t *mdnsd_list(mdns_daemon_t *d,const char *host, int type, mdns_answer_t *last)
{
  return (mdns_answer_t *)_c_next(d, (struct cached *)last, host, type);
}

mdns_record_t *mdnsd_record_next(const mdns_record_t* r)
{
  return r ? r->next : NULL;
}

const mdns_answer_t *mdnsd_record_data(const mdns_record_t* r)
{
  return &r->rr;
}

mdns_record_t *mdnsd_shared(mdns_daemon_t *d, const char *host, unsigned short type, unsigned long ttl)
{
  int i = _namehash(host) % SPRIME;
  mdns_record_t *r;

  r = calloc(1, sizeof(struct mdns_record));
  if (!r)
    return NULL;

  r->rr.name = strdup(host);
  if (!r->rr.name) {
    free(r);
    return NULL;
  }

  r->rr.type = type;
  r->rr.ttl = ttl;
  r->next = d->published[i];
  d->published[i] = r;

  return r;
}

mdns_record_t *mdnsd_unique(mdns_daemon_t *d, const char *host, unsigned short type, unsigned long ttl,
          void (*conflict)(char *host, int type, void *arg), void *arg)
{
  mdns_record_t *r;

  r = mdnsd_shared(d, host, type, ttl);
  if (!r)
    return NULL;

  r->conflict = conflict;
  r->arg = arg;
  r->unique = 1;

  /* check if r already in other lists. If yes, remove it from there */
  _r_remove_lists(d, r, &d->probing);
  _r_push(&d->probing, r);

  d->probe.tv_sec = d->now.tv_sec;
  d->probe.tv_usec = d->now.tv_usec;

  return r;
}

mdns_record_t *mdnsd_get_published(mdns_daemon_t *d, const char *host)
{
  return d->published[_namehash(host) % SPRIME];
}

int mdnsd_has_query(mdns_daemon_t *d, const char *host)
{
  return d->queries[_namehash(host) % SPRIME] != NULL;
}

mdns_record_t *mdnsd_find(mdns_daemon_t *d, const char *name, unsigned short type)
{
  mdns_record_t *r;

  r = mdnsd_get_published(d, name);
  while (r) {
    const mdns_answer_t *data;

    /*
     * Search for a record with the same type and name.
     * Records with different names might be in the same
     * linked list when the hash functions % SPRIME assigns
     * them the same index (hash collision)
     */
    data = mdnsd_record_data(r);
    if (data->type == type && strcmp(data->name, name) == 0)
      return r;

    r = mdnsd_record_next(r);
  }

  return NULL;
}

void mdnsd_done(mdns_daemon_t *d, mdns_record_t *r)
{
  mdns_record_t *cur;

  if (r->unique && r->unique < 5) {
    /* Probing yet, zap from that list first! */
    if (d->probing == r) {
      d->probing = r->list;
    } else {
      for (cur = d->probing; cur->list != r; cur = cur->list)
        ;
      cur->list = r->list;
    }

    _r_done(d, r);
    return;
  }

  r->rr.ttl = 0;
  _r_send(d, r);
}

void mdnsd_set_raw(mdns_daemon_t *d, mdns_record_t *r, const char *data, unsigned short len)
{
  if (r->rr.rdata)
    free(r->rr.rdata);

  r->rr.rdata = malloc(len);
  if (r->rr.rdata) {
    memcpy(r->rr.rdata, data, len);
    r->rr.rdlen = len;
  }
  _r_publish(d, r);
}

void mdnsd_set_host(mdns_daemon_t *d, mdns_record_t *r, const char *name)
{
  if (!r)
    return;

  if (r->rr.rdname)
    free(r->rr.rdname);
  r->rr.rdname = strdup(name);
  _r_publish(d, r);
}

void mdnsd_set_ip(mdns_daemon_t *d, mdns_record_t *r, struct in_addr ip)
{
  r->rr.ip = ip;
  _r_publish(d, r);
}

void mdnsd_set_ipv6(mdns_daemon_t *d, mdns_record_t *r, struct in6_addr ip6)
{
  r->rr.ip6 = ip6;
  _r_publish(d, r);
}

void mdnsd_set_srv(mdns_daemon_t *d, mdns_record_t *r, unsigned short priority, unsigned short weight, unsigned short port, char *name)
{
  r->rr.srv.priority = priority;
  r->rr.srv.weight = weight;
  r->rr.srv.port = port;
  mdnsd_set_host(d, r, name);
}

/* Internal helper: update set of addresses for given host & type (A/AAAA) */
static int _update_addresses_for_host(mdns_daemon_t *d, const char *host, unsigned short type, const void *addrs, size_t count)
{
  mdns_record_t *r;
  mdns_record_t *cur;
  unsigned long ttl = 120; /* default TTL if none exists */
  char buf6[INET6_ADDRSTRLEN];

  if (!d || !host)
    return -1;

  /* Determine TTL from any existing record of this type */
  r = mdnsd_find(d, host, type);
  if (r) {
    const mdns_answer_t *data = mdnsd_record_data(r);
    if (data && data->ttl)
      ttl = data->ttl;
  }

  /* For each desired address, check if there's a matching existing record */
  for (size_t i = 0; i < count; i++) {
    bool found = false;
    cur = mdnsd_get_published(d, host);
    while (cur) {
      const mdns_answer_t *data = mdnsd_record_data(cur);
      if (data->type == type && strcmp(data->name, host) == 0) {
        if (type == QTYPE_A) {
          const struct in_addr *a = (const struct in_addr *)addrs;
          if (data->ip.s_addr == a[i].s_addr) {
            found = true;
            INFO("Found A record for %s addr %s", host, inet_ntoa(a[i]));
            break;
          }
        } else if (type == QTYPE_AAAA) {
          const struct in6_addr *a6 = (const struct in6_addr *)addrs;
          if (memcmp(&data->ip6, &a6[i], sizeof(struct in6_addr)) == 0) {
            found = true;
            INFO("Found AAAA record for %s addr %s", host, inet_ntop(AF_INET6, &a6[i], buf6, sizeof(buf6)));
            break;
          }
        }
      }
      cur = mdnsd_record_next(cur);
    }
    if (!found) {
      /* Create new_ record for this address */
      mdns_record_t *nr = mdnsd_shared(d, host, type, ttl);
      if (!nr)
        continue;
      if (type == QTYPE_A) {
        const struct in_addr *a = (const struct in_addr *)addrs;
        mdnsd_set_ip(d, nr, a[i]);
        INFO("Created A record for %s addr %s", host, inet_ntoa(a[i]));
      } else {
        const struct in6_addr *a6 = (const struct in6_addr *)addrs;
        mdnsd_set_ipv6(d, nr, a6[i]);
        INFO("Created AAAA record for %s addr %s", host, inet_ntop(AF_INET6, &a6[i], buf6, sizeof(buf6)));
      }
    }
  }

  /* Remove stale records (present but not in desired set) */
  cur = mdnsd_get_published(d, host);
  while (cur) {
    mdns_record_t *next = mdnsd_record_next(cur);
    const mdns_answer_t *data = mdnsd_record_data(cur);
    if (data->type == type && strcmp(data->name, host) == 0) {
      bool still_present = false;
      for (size_t i = 0; i < count; i++) {
        if (type == QTYPE_A) {
          const struct in_addr *a = (const struct in_addr *)addrs;
          if (data->ip.s_addr == a[i].s_addr) { still_present = true; break; }
        } else {
          const struct in6_addr *a6 = (const struct in6_addr *)addrs;
          if (memcmp(&data->ip6, &a6[i], sizeof(struct in6_addr)) == 0) { still_present = true; break; }
        }
      }
      if (!still_present)
        mdnsd_done(d, cur);
    }
    cur = next;
  }

  return 0;
}

int mdnsd_set_addresses_for_host(mdns_daemon_t *d, const char *host, const struct in_addr *addrs, size_t count)
{
  return _update_addresses_for_host(d, host, QTYPE_A, addrs, count);
}

int mdnsd_set_ipv6_addresses_for_host(mdns_daemon_t *d, const char *host, const struct in6_addr *addrs, size_t count)
{
  return _update_addresses_for_host(d, host, QTYPE_AAAA, addrs, count);
}

int mdnsd_set_interface_addresses(mdns_daemon_t *d, const char *ifname)
{
  struct ifaddrs *ifa = NULL;
  struct ifaddrs *it;
  struct in_addr *v4 = NULL; size_t v4c = 0;
  struct in6_addr *v6 = NULL; size_t v6c = 0;
  char buf[INET_ADDRSTRLEN];
  char buf6[INET6_ADDRSTRLEN];

  if (getifaddrs(&ifa) != 0)
    return -1;

  /* Collect all v4/v6 addresses for the interface */
  for (it = ifa; it; it = it->ifa_next) {
    if (!it->ifa_addr || !it->ifa_name || strcmp(it->ifa_name, ifname))
      continue;
    if (it->ifa_addr->sa_family == AF_INET) {
      v4 = realloc(v4, (v4c + 1) * sizeof(*v4));
      if (v4) {
        struct sockaddr_in *sin = (struct sockaddr_in *)it->ifa_addr;
        v4[v4c++] = sin->sin_addr;
        if(inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)))
            INFO("Adding address %s for interface %s", buf, ifname);
      }
    } else if (it->ifa_addr->sa_family == AF_INET6) {
      v6 = realloc(v6, (v6c + 1) * sizeof(*v6));
      if (v6) {
        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)it->ifa_addr;
        v6[v6c++] = sin6->sin6_addr;
        if (inet_ntop(AF_INET6, &sin6->sin6_addr, buf6, sizeof(buf6)))
            INFO("Adding address %s for interface %s", buf6, ifname);
      }
    }
  }
  freeifaddrs(ifa);

  /*
   * Reconcile per host name, not per record pointer: the calls below
   * free stale records, which would dangle a record iterator.  See #92.
   */
  char **hosts = NULL;
  size_t hostc = 0;

  for (size_t idx = 0; idx < SPRIME; idx++) {
    for (mdns_record_t *cur = d->published[idx]; cur; cur = mdnsd_record_next(cur)) {
      const mdns_answer_t *data = mdnsd_record_data(cur);
      bool seen = false;
      char **tmp;

      if (data->type != QTYPE_A && data->type != QTYPE_AAAA)
        continue;

      for (size_t i = 0; i < hostc; i++) {
        if (!strcmp(hosts[i], data->name)) {
          seen = true;
          break;
        }
      }
      if (seen)
        continue;

      tmp = realloc(hosts, (hostc + 1) * sizeof(*hosts));
      if (!tmp)
        continue;
      hosts = tmp;
      hosts[hostc] = strdup(data->name);
      if (hosts[hostc])
        hostc++;
    }
  }

  for (size_t i = 0; i < hostc; i++) {
    INFO("Updating addresses for host %s", hosts[i]);
    /* A count of 0 is intentional: it withdraws that whole family. */
    mdnsd_set_addresses_for_host(d, hosts[i], v4, v4c);
    mdnsd_set_ipv6_addresses_for_host(d, hosts[i], v6, v6c);
    free(hosts[i]);
  }
  free(hosts);

  free(v4);
  free(v6);
  return 0;
}

static int process_in(mdns_daemon_t *d, int sd)
{
  static unsigned char buf[MAX_PACKET_LEN + 1];
  inet_addr_t from;
  socklen_t ssize = sizeof(from);
  ssize_t bsize;

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

  while ((bsize = recvfrom(sd, buf, MAX_PACKET_LEN, MSG_DONTWAIT, (struct sockaddr *)&from, &ssize)) > 0) {
    struct message m = { 0 };
    int rc;

    buf[MAX_PACKET_LEN] = 0;
    mdnsd_log_hex("Got Data:", buf, bsize);

    rc = message_parse(&m, buf);
    if (rc)
      continue;
    rc = mdnsd_in(d, &m, &from);
    if (rc)
      continue;
  }

  if (bsize < 0 && errno != EAGAIN)
    return 1;

  return 0;
}

static int process_out(mdns_daemon_t *d, int sd)
{
  inet_addr_t to;
  struct message m;

  while (mdnsd_out(d, &m, &to)) {
    unsigned char *buf;
    ssize_t len;

    len = message_packet_len(&m);
    buf = message_packet(&m);
    mdnsd_log_hex("Send Data:", buf, len);

    if (sendto(sd, buf, len, MSG_DONTWAIT, (struct sockaddr *)&to, inet_len(&to)) != len)
      return 2;
  }

  return 0;
}

int mdnsd_step(mdns_daemon_t *d, int sd, bool in, bool out, struct timeval *tv)
{
  int rc = 0;

  if (in)
    rc = process_in(d, sd);
  if (!rc && out)
    rc = process_out(d, sd);

  if (!rc && tv) {
    struct timeval *delay;

    delay = mdnsd_sleep(d);
    memcpy(tv, delay, sizeof(*tv));
  }

  /* Service Enumeration/Discovery completed */
  if (d && d->disco)
    d->disco = 0;

  return rc;
}

void records_clear(mdns_daemon_t *d)
{
  for (int i = 0; i < SPRIME; i++)
  {
    mdns_record_t *r = d->published[i];
    while (r)
    {
      mdns_record_t *const next = r->next;
      _r_remove_lists(d, r, NULL);
      _u_remove(d, r);
      _free_record(r);
      r = next;
    }
    d->published[i] = NULL;
  }
}

Coverage Report

Created: 2026-08-14 07:31