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Caching cleanup. Use cached NXDOMAIN to answer queries of any type.

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This commit is contained in:
Simon Kelley
2021-09-05 18:47:45 +01:00
parent 51d56df7a3
commit 1ce1c6beae
1 changed files with 85 additions and 54 deletions
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125
src/rfc1035.c
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@@ -787,7 +787,10 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
if (!extract_name(header, qlen, &p1, name, 1, 0))
return 0;
goto cname_loop1;
if (qtype != T_CNAME)
goto cname_loop1;
found = 1;
}
else if (aqtype != qtype)
{
@@ -877,8 +880,19 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
return 0; /* bad packet */
}
if (!found && !option_bool(OPT_NO_NEG))
if (!found && (qtype != T_ANY || (flags & F_NXDOMAIN)))
{
if (flags & F_NXDOMAIN)
{
flags &= ~(F_IPV4 | F_IPV6 | F_SRV);
/* Can store NXDOMAIN reply to CNAME or ANY query. */
if (qtype == T_CNAME || qtype == T_ANY)
insert = 1;
}
log_query(F_UPSTREAM | F_FORWARD | F_NEG | flags | (secure ? F_DNSSECOK : 0), name, NULL, NULL);
if (!searched_soa)
{
searched_soa = 1;
@@ -887,22 +901,17 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
/* If there's no SOA to get the TTL from, but there is a CNAME
pointing at this, inherit its TTL */
if (ttl || cpp)
if (insert && !option_bool(OPT_NO_NEG) && (ttl || cpp))
{
if (ttl == 0)
ttl = cttl;
log_query(F_UPSTREAM | F_FORWARD | F_NEG | flags | (secure ? F_DNSSECOK : 0), name, NULL, NULL);
if (insert)
newc = cache_insert(name, NULL, C_IN, now, ttl, F_FORWARD | F_NEG | flags | (secure ? F_DNSSECOK : 0));
if (newc && cpp)
{
newc = cache_insert(name, NULL, C_IN, now, ttl, F_FORWARD | F_NEG | flags | (secure ? F_DNSSECOK : 0));
if (newc && cpp)
{
next_uid(newc);
cpp->addr.cname.target.cache = newc;
cpp->addr.cname.uid = newc->uid;
}
next_uid(newc);
cpp->addr.cname.target.cache = newc;
cpp->addr.cname.uid = newc->uid;
}
}
}
@@ -1440,35 +1449,54 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
ans = 0; /* have we answered this question */
while (--count != 0 && (crecp = cache_find_by_name(NULL, name, now, F_CNAME)))
{
char *cname_target = cache_get_cname_target(crecp);
if (qclass == C_IN)
while (--count != 0 && (crecp = cache_find_by_name(NULL, name, now, F_CNAME | F_NXDOMAIN)))
{
char *cname_target;
/* If the client asked for DNSSEC don't use cached data. */
if ((crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)) ||
(rd_bit && (!do_bit || cache_validated(crecp))))
{
if (crecp->flags & F_CONFIG || qtype == T_CNAME)
ans = 1;
if (crecp->flags & F_NXDOMAIN)
{
if (qtype == T_CNAME)
{
if (!dryrun)
log_query(crecp->flags, name, NULL, record_source(crecp->uid));
auth = 0;
nxdomain = 1;
ans = 1;
}
break;
}
if (!(crecp->flags & F_DNSSECOK))
sec_data = 0;
cname_target = cache_get_cname_target(crecp);
if (!dryrun)
{
log_query(crecp->flags, name, NULL, record_source(crecp->uid));
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp,
crec_ttl(crecp, now), &nameoffset,
T_CNAME, C_IN, "d", cname_target))
anscount++;
}
/* If the client asked for DNSSEC don't use cached data. */
if ((crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)) ||
(rd_bit && (!do_bit || cache_validated(crecp))))
{
if (crecp->flags & F_CONFIG || qtype == T_CNAME)
ans = 1;
}
else
return 0; /* give up if any cached CNAME in chain can't be used for DNSSEC reasons. */
if (!(crecp->flags & F_DNSSECOK))
sec_data = 0;
strcpy(name, cname_target);
}
if (!dryrun)
{
log_query(crecp->flags, name, NULL, record_source(crecp->uid));
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp,
crec_ttl(crecp, now), &nameoffset,
T_CNAME, C_IN, "d", cname_target))
anscount++;
}
}
else
return 0; /* give up if any cached CNAME in chain can't be used for DNSSEC reasons. */
if (qtype == T_CNAME)
break;
strcpy(name, cname_target);
}
if (qtype == T_TXT || qtype == T_ANY)
{
@@ -1612,7 +1640,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
}
}
else if ((crecp = cache_find_by_addr(NULL, &addr, now, is_arpa)))
else if (is_arpa && (crecp = cache_find_by_addr(NULL, &addr, now, is_arpa)))
{
/* Don't use cache when DNSSEC data required, unless we know that
the zone is unsigned, which implies that we're doing
@@ -1751,7 +1779,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
continue;
}
if ((crecp = cache_find_by_name(NULL, name, now, flag | (dryrun ? F_NO_RR : 0))))
if ((crecp = cache_find_by_name(NULL, name, now, flag | F_NXDOMAIN | (dryrun ? F_NO_RR : 0))))
{
int localise = 0;
@@ -1915,16 +1943,20 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
if (!found)
{
if ((crecp = cache_find_by_name(NULL, name, now, F_SRV | (dryrun ? F_NO_RR : 0))) &&
if ((crecp = cache_find_by_name(NULL, name, now, F_SRV | F_NXDOMAIN | (dryrun ? F_NO_RR : 0))) &&
rd_bit && (!do_bit || (option_bool(OPT_DNSSEC_VALID) && !(crecp->flags & F_DNSSECOK))))
{
if (!(crecp->flags & F_DNSSECOK))
sec_data = 0;
do
{
/* don't answer wildcard queries with data not from /etc/hosts or dhcp leases, except for NXDOMAIN */
if (qtype == T_ANY && !(crecp->flags & (F_NXDOMAIN)))
break;
auth = 0;
found = ans = 1;
if (!(crecp->flags & F_DNSSECOK))
sec_data = 0;
auth = 0;
found = ans = 1;
do {
if (crecp->flags & F_NEG)
{
if (crecp->flags & F_NXDOMAIN)
@@ -1945,7 +1977,6 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
}
} while ((crecp = cache_find_by_name(crecp, name, now, F_SRV)));
}
}
if (!found && option_bool(OPT_FILTER) && (qtype == T_SRV || (qtype == T_ANY && strchr(name, '_'))))
{