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Cache SRV records.

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Inpsired by a patch from Jeremy Allison, but completely re-rolled
by srk. All bugs are mine.
This commit is contained in:
Simon Kelley
2019-01-06 23:09:50 +00:00
parent 2daca52b80
commit 5b99eae59d
6 changed files with 166 additions and 66 deletions
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141
src/rfc1035.c
View File

@@ -726,7 +726,7 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
{
/* everything other than PTR */
struct crec *newc;
int addrlen;
int addrlen = 0;
if (qtype == T_A)
{
@@ -738,7 +738,9 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
addrlen = IN6ADDRSZ;
flags |= F_IPV6;
}
else
else if (qtype == T_SRV)
flags |= F_SRV;
else
continue;
cname_loop1:
@@ -799,39 +801,61 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
{
found = 1;
/* copy address into aligned storage */
if (!CHECK_LEN(header, p1, qlen, addrlen))
return 0; /* bad packet */
memcpy(&addr, p1, addrlen);
/* check for returned address in private space */
if (check_rebind)
if (flags & F_SRV)
{
if ((flags & F_IPV4) &&
private_net(addr.addr4, !option_bool(OPT_LOCAL_REBIND)))
return 1;
if ((flags & F_IPV6) &&
IN6_IS_ADDR_V4MAPPED(&addr.addr6))
unsigned char *tmp = namep;
if (!CHECK_LEN(header, p1, qlen, 6))
return 0; /* bad packet */
GETSHORT(addr.srv.priority, p1);
GETSHORT(addr.srv.weight, p1);
GETSHORT(addr.srv.srvport, p1);
if (!extract_name(header, qlen, &p1, name, 1, 0))
return 0;
addr.srv.targetlen = strlen(name) + 1; /* include terminating zero */
if (!(addr.srv.target = blockdata_alloc(name, addr.srv.targetlen)))
return 0;
/* we overwrote the original name, so get it back here. */
if (!extract_name(header, qlen, &tmp, name, 1, 0))
return 0;
}
else
{
/* copy address into aligned storage */
if (!CHECK_LEN(header, p1, qlen, addrlen))
return 0; /* bad packet */
memcpy(&addr, p1, addrlen);
/* check for returned address in private space */
if (check_rebind)
{
struct in_addr v4;
v4.s_addr = ((const uint32_t *) (&addr.addr6))[3];
if (private_net(v4, !option_bool(OPT_LOCAL_REBIND)))
if ((flags & F_IPV4) &&
private_net(addr.addr4, !option_bool(OPT_LOCAL_REBIND)))
return 1;
if ((flags & F_IPV6) &&
IN6_IS_ADDR_V4MAPPED(&addr.addr6))
{
struct in_addr v4;
v4.s_addr = ((const uint32_t *) (&addr.addr6))[3];
if (private_net(v4, !option_bool(OPT_LOCAL_REBIND)))
return 1;
}
}
}
#ifdef HAVE_IPSET
if (ipsets && (flags & (F_IPV4 | F_IPV6)))
{
ipsets_cur = ipsets;
while (*ipsets_cur)
if (ipsets && (flags & (F_IPV4 | F_IPV6)))
{
log_query((flags & (F_IPV4 | F_IPV6)) | F_IPSET, name, &addr, *ipsets_cur);
add_to_ipset(*ipsets_cur++, &addr, flags, 0);
ipsets_cur = ipsets;
while (*ipsets_cur)
{
log_query((flags & (F_IPV4 | F_IPV6)) | F_IPSET, name, &addr, *ipsets_cur);
add_to_ipset(*ipsets_cur++, &addr, flags, 0);
}
}
}
#endif
}
newc = cache_insert(name, &addr, C_IN, now, attl, flags | F_FORWARD | secflag);
if (newc && cpp)
@@ -1844,7 +1868,68 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
*up = move;
move->next = NULL;
}
if (!found)
{
cname_srv_restart:
if ((crecp = cache_find_by_name(NULL, name, now, F_CNAME | F_SRV | (dryrun ? F_NO_RR : 0))) &&
(!do_bit || (option_bool(OPT_DNSSEC_VALID) && !(crecp->flags & F_DNSSECOK))))
{
if (!(crecp->flags & F_DNSSECOK))
sec_data = 0;
auth = 0;
found = ans = 1;
do {
if (crecp->flags & F_CNAME)
{
char *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++;
}
strcpy(name, cname_target);
goto cname_srv_restart;
}
else if (crecp->flags & F_NEG)
{
if (crecp->flags & F_NXDOMAIN)
nxdomain = 1;
if (!dryrun)
log_query(crecp->flags, name, NULL, NULL);
}
else
{
unsigned char *p1 = ((unsigned char *)header) + nameoffset;
if (!dryrun)
{
log_query(crecp->flags, name, NULL, 0);
blockdata_retrieve(crecp->addr.srv.target, crecp->addr.srv.targetlen, name);
if (add_resource_record(header, limit, &trunc, nameoffset, &ansp,
crec_ttl(crecp, now), NULL, T_SRV, C_IN, "sssd",
crecp->addr.srv.priority, crecp->addr.srv.weight, crecp->addr.srv.srvport,
name))
anscount++;
/* restore name we overwrote */
if (!extract_name(header, qlen, &p1, name, 1, 0))
return 0; /* bad packet */
}
}
} while ((crecp = cache_find_by_name(crecp, name, now, F_SRV | F_CNAME)));
}
}
if (!found && option_bool(OPT_FILTER) && (qtype == T_SRV || (qtype == T_ANY && strchr(name, '_'))))
{
ans = 1;