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Generalise locally-configured CNAME handling.

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It's now possible for the target of a CNAME to be any locally
configured RR or even point to a non-existent RR.
This commit is contained in:
Simon Kelley
2019-10-29 22:24:19 +00:00
parent 456a319775
commit 84449bf41c
4 changed files with 34 additions and 108 deletions
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119
src/cache.c
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@@ -276,10 +276,10 @@ char *cache_get_name(struct crec *crecp)
char *cache_get_cname_target(struct crec *crecp)
{
if (crecp->addr.cname.uid != SRC_INTERFACE)
if (crecp->addr.cname.uid != SRC_PTR)
return cache_get_name(crecp->addr.cname.target.cache);
return crecp->addr.cname.target.int_name->name;
return crecp->addr.cname.target.name;
}
@@ -309,7 +309,7 @@ struct crec *cache_enumerate(int init)
static int is_outdated_cname_pointer(struct crec *crecp)
{
if (!(crecp->flags & F_CNAME) || crecp->addr.cname.uid == SRC_INTERFACE)
if (!(crecp->flags & F_CNAME) || crecp->addr.cname.uid == SRC_PTR)
return 0;
/* NB. record may be reused as DS or DNSKEY, where uid is
@@ -513,7 +513,7 @@ static struct crec *really_insert(char *name, union all_addr *addr, unsigned sho
{
/* We're trying to insert a record over one from
/etc/hosts or DHCP, or other config. If the
existing record is for an A or AAAA and
existing record is for an A or AAAA or CNAME and
the record we're trying to insert is the same,
just drop the insert, but don't error the whole process. */
if ((flags & (F_IPV4 | F_IPV6)) && (flags & F_FORWARD) && addr)
@@ -525,7 +525,7 @@ static struct crec *really_insert(char *name, union all_addr *addr, unsigned sho
IN6_ARE_ADDR_EQUAL(&new->addr.addr6, &addr->addr6))
return new;
}
insert_error = 1;
return NULL;
}
@@ -956,48 +956,20 @@ struct crec *cache_find_by_addr(struct crec *crecp, union all_addr *addr,
return NULL;
}
static void add_hosts_cname(struct crec *target)
{
struct crec *crec;
struct cname *a;
for (a = daemon->cnames; a; a = a->next)
if (a->alias[1] != '*' &&
hostname_isequal(cache_get_name(target), a->target) &&
(crec = whine_malloc(SIZEOF_POINTER_CREC)))
{
crec->flags = F_FORWARD | F_IMMORTAL | F_NAMEP | F_CONFIG | F_CNAME;
crec->ttd = a->ttl;
crec->name.namep = a->alias;
crec->addr.cname.target.cache = target;
next_uid(target);
crec->addr.cname.uid = target->uid;
crec->uid = UID_NONE;
cache_hash(crec);
make_non_terminals(crec);
add_hosts_cname(crec); /* handle chains */
}
}
static void add_hosts_entry(struct crec *cache, union all_addr *addr, int addrlen,
unsigned int index, struct crec **rhash, int hashsz)
{
struct crec *lookup = cache_find_by_name(NULL, cache_get_name(cache), 0, cache->flags & (F_IPV4 | F_IPV6));
int i, nameexists = 0;
int i;
unsigned int j;
/* Remove duplicates in hosts files. */
if (lookup && (lookup->flags & F_HOSTS))
if (lookup && (lookup->flags & F_HOSTS) && memcmp(&lookup->addr, addr, addrlen) == 0)
{
nameexists = 1;
if (memcmp(&lookup->addr, addr, addrlen) == 0)
{
free(cache);
return;
}
free(cache);
return;
}
/* Ensure there is only one address -> name mapping (first one trumps)
We do this by steam here, The entries are kept in hash chains, linked
by ->next (which is unused at this point) held in hash buckets in
@@ -1048,10 +1020,6 @@ static void add_hosts_entry(struct crec *cache, union all_addr *addr, int addrle
memcpy(&cache->addr, addr, addrlen);
cache_hash(cache);
make_non_terminals(cache);
/* don't need to do alias stuff for second and subsequent addresses. */
if (!nameexists)
add_hosts_cname(cache);
}
static int eatspace(FILE *f)
@@ -1211,7 +1179,6 @@ void cache_reload(void)
struct host_record *hr;
struct name_list *nl;
struct cname *a;
struct interface_name *intr;
#ifdef HAVE_DNSSEC
struct ds_config *ds;
#endif
@@ -1244,24 +1211,21 @@ void cache_reload(void)
up = &cache->hash_next;
}
/* Add CNAMEs to interface_names to the cache */
/* Add locally-configured CNAMEs to the cache */
for (a = daemon->cnames; a; a = a->next)
for (intr = daemon->int_names; intr; intr = intr->next)
if (a->alias[1] != '*' &&
hostname_isequal(a->target, intr->name) &&
((cache = whine_malloc(SIZEOF_POINTER_CREC))))
{
cache->flags = F_FORWARD | F_NAMEP | F_CNAME | F_IMMORTAL | F_CONFIG;
cache->ttd = a->ttl;
cache->name.namep = a->alias;
cache->addr.cname.target.int_name = intr;
cache->addr.cname.uid = SRC_INTERFACE;
cache->uid = UID_NONE;
cache_hash(cache);
make_non_terminals(cache);
add_hosts_cname(cache); /* handle chains */
}
if (a->alias[1] != '*' &&
((cache = whine_malloc(SIZEOF_POINTER_CREC))))
{
cache->flags = F_FORWARD | F_NAMEP | F_CNAME | F_IMMORTAL | F_CONFIG;
cache->ttd = a->ttl;
cache->name.namep = a->alias;
cache->addr.cname.target.name = a->target;
cache->addr.cname.uid = SRC_PTR;
cache->uid = UID_NONE;
cache_hash(cache);
make_non_terminals(cache);
}
#ifdef HAVE_DNSSEC
for (ds = daemon->ds; ds; ds = ds->next)
if ((cache = whine_malloc(SIZEOF_POINTER_CREC)) &&
@@ -1364,39 +1328,6 @@ void cache_unhash_dhcp(void)
up = &cache->hash_next;
}
static void add_dhcp_cname(struct crec *target, time_t ttd)
{
struct crec *aliasc;
struct cname *a;
for (a = daemon->cnames; a; a = a->next)
if (a->alias[1] != '*' &&
hostname_isequal(cache_get_name(target), a->target))
{
if ((aliasc = dhcp_spare))
dhcp_spare = dhcp_spare->next;
else /* need new one */
aliasc = whine_malloc(SIZEOF_POINTER_CREC);
if (aliasc)
{
aliasc->flags = F_FORWARD | F_NAMEP | F_DHCP | F_CNAME | F_CONFIG;
if (ttd == 0)
aliasc->flags |= F_IMMORTAL;
else
aliasc->ttd = ttd;
aliasc->name.namep = a->alias;
aliasc->addr.cname.target.cache = target;
next_uid(target);
aliasc->addr.cname.uid = target->uid;
aliasc->uid = UID_NONE;
cache_hash(aliasc);
make_non_terminals(aliasc);
add_dhcp_cname(aliasc, ttd);
}
}
}
void cache_add_dhcp_entry(char *host_name, int prot,
union all_addr *host_address, time_t ttd)
{
@@ -1479,8 +1410,6 @@ void cache_add_dhcp_entry(char *host_name, int prot,
crec->uid = UID_NONE;
cache_hash(crec);
make_non_terminals(crec);
add_dhcp_cname(crec, ttd);
}
}
#endif