#include "utf8.h"
#include "util.h"
+#include "strv.h"
#include "resolved-dns-domain.h"
#include "resolved-dns-packet.h"
h = DNS_PACKET_HEADER(p);
- if (protocol == DNS_PROTOCOL_DNS)
- h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0, 0, 0, 0, 1, 0, 0, 0, 0)); /* ask for recursion */
+ if (protocol == DNS_PROTOCOL_LLMNR)
+ h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
+ 0 /* opcode */,
+ 0 /* c */,
+ 0 /* tc */,
+ 0 /* t */,
+ 0 /* ra */,
+ 0 /* ad */,
+ 0 /* cd */,
+ 0 /* rcode */));
else
- h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0));
+ h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
+ 0 /* opcode */,
+ 0 /* aa */,
+ 0 /* tc */,
+ 1 /* rd (ask for recursion) */,
+ 0 /* ra */,
+ 0 /* ad */,
+ 0 /* cd */,
+ 0 /* rcode */));
*ret = p;
return 0;
if (p->size > DNS_PACKET_SIZE_MAX)
return -EBADMSG;
- return 0;
+ return 1;
}
int dns_packet_validate_reply(DnsPacket *p) {
if (r < 0)
return r;
- if (DNS_PACKET_QR(p) == 0)
+ if (DNS_PACKET_QR(p) != 1)
+ return 0;
+
+ if (DNS_PACKET_OPCODE(p) != 0)
return -EBADMSG;
+ /* RFC 4795, Section 2.1.1. says to discard all replies with QDCOUNT != 1 */
+ if (p->protocol == DNS_PROTOCOL_LLMNR &&
+ DNS_PACKET_QDCOUNT(p) != 1)
+ return -EBADMSG;
+
+ return 1;
+}
+
+int dns_packet_validate_query(DnsPacket *p) {
+ int r;
+
+ assert(p);
+
+ r = dns_packet_validate(p);
+ if (r < 0)
+ return r;
+
+ if (DNS_PACKET_QR(p) != 0)
+ return 0;
+
if (DNS_PACKET_OPCODE(p) != 0)
return -EBADMSG;
- return 0;
+ if (DNS_PACKET_TC(p))
+ return -EBADMSG;
+
+ /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */
+ if (p->protocol == DNS_PROTOCOL_LLMNR &&
+ DNS_PACKET_QDCOUNT(p) != 1)
+ return -EBADMSG;
+
+ /* RFC 4795, Section 2.1.1. says to discard all queries with ANCOUNT != 0 */
+ if (DNS_PACKET_ANCOUNT(p) > 0)
+ return -EBADMSG;
+
+ /* RFC 4795, Section 2.1.1. says to discard all queries with NSCOUNT != 0 */
+ if (DNS_PACKET_NSCOUNT(p) > 0)
+ return -EBADMSG;
+
+ return 1;
}
static int dns_packet_extend(DnsPacket *p, size_t add, void **ret, size_t *start) {
p->size = sz;
}
+int dns_packet_append_blob(DnsPacket *p, const void *d, size_t l, size_t *start) {
+ void *q;
+ int r;
+
+ assert(p);
+
+ r = dns_packet_extend(p, l, &q, start);
+ if (r < 0)
+ return r;
+
+ memcpy(q, d, l);
+ return 0;
+}
+
int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start) {
void *d;
int r;
return r;
((uint8_t*) d)[0] = (uint8_t) (v >> 8);
- ((uint8_t*) d)[1] = (uint8_t) (v & 255);
+ ((uint8_t*) d)[1] = (uint8_t) v;
+
+ return 0;
+}
+
+int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start) {
+ void *d;
+ int r;
+
+ assert(p);
+
+ r = dns_packet_extend(p, sizeof(uint32_t), &d, start);
+ if (r < 0)
+ return r;
+
+ ((uint8_t*) d)[0] = (uint8_t) (v >> 24);
+ ((uint8_t*) d)[1] = (uint8_t) (v >> 16);
+ ((uint8_t*) d)[2] = (uint8_t) (v >> 8);
+ ((uint8_t*) d)[3] = (uint8_t) v;
return 0;
}
return r;
}
+int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start) {
+ size_t saved_size, rdlength_offset, end, rdlength;
+ int r;
+
+ assert(p);
+ assert(rr);
+
+ saved_size = p->size;
+
+ r = dns_packet_append_key(p, rr->key, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint32(p, rr->ttl, NULL);
+ if (r < 0)
+ goto fail;
+
+ /* Initially we write 0 here */
+ r = dns_packet_append_uint16(p, 0, &rdlength_offset);
+ if (r < 0)
+ goto fail;
+
+ switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {
+
+ case DNS_TYPE_PTR:
+ case DNS_TYPE_NS:
+ case DNS_TYPE_CNAME:
+ case DNS_TYPE_DNAME:
+ r = dns_packet_append_name(p, rr->ptr.name, NULL);
+ break;
+
+ case DNS_TYPE_HINFO:
+ r = dns_packet_append_string(p, rr->hinfo.cpu, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_string(p, rr->hinfo.os, NULL);
+ break;
+
+ case DNS_TYPE_SPF: /* exactly the same as TXT */
+ case DNS_TYPE_TXT: {
+ char **s;
+
+ STRV_FOREACH(s, rr->txt.strings) {
+ r = dns_packet_append_string(p, *s, NULL);
+ if (r < 0)
+ goto fail;
+ }
+
+ break;
+ }
+
+ case DNS_TYPE_A:
+ r = dns_packet_append_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL);
+ break;
+
+ case DNS_TYPE_AAAA:
+ r = dns_packet_append_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL);
+ break;
+
+ case DNS_TYPE_SOA:
+ r = dns_packet_append_name(p, rr->soa.mname, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_name(p, rr->soa.rname, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint32(p, rr->soa.serial, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint32(p, rr->soa.refresh, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint32(p, rr->soa.retry, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint32(p, rr->soa.expire, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint32(p, rr->soa.minimum, NULL);
+ break;
+
+ case DNS_TYPE_MX:
+ r = dns_packet_append_uint16(p, rr->mx.priority, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_name(p, rr->mx.exchange, NULL);
+ break;
+
+ case DNS_TYPE_LOC:
+ r = dns_packet_append_uint8(p, rr->loc.version, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint8(p, rr->loc.size, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint8(p, rr->loc.horiz_pre, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint8(p, rr->loc.vert_pre, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint16(p, rr->loc.latitude, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint16(p, rr->loc.longitude, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_append_uint16(p, rr->loc.altitude, NULL);
+ break;
+
+ case DNS_TYPE_SRV:
+ case DNS_TYPE_SSHFP:
+ case _DNS_TYPE_INVALID: /* unparseable */
+ default:
+
+ r = dns_packet_append_blob(p, rr->generic.data, rr->generic.size, NULL);
+ break;
+ }
+ if (r < 0)
+ goto fail;
+
+ /* Let's calculate the actual data size and update the field */
+ rdlength = p->size - rdlength_offset - sizeof(uint16_t);
+ if (rdlength > 0xFFFF) {
+ r = ENOSPC;
+ goto fail;
+ }
+
+ end = p->size;
+ p->size = rdlength_offset;
+ r = dns_packet_append_uint16(p, rdlength, NULL);
+ if (r < 0)
+ goto fail;
+ p->size = end;
+
+ if (start)
+ *start = saved_size;
+
+ return 0;
+
+fail:
+ dns_packet_truncate(p, saved_size);
+ return r;
+}
+
+
int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) {
assert(p);
p->rindex = idx;
}
+int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start) {
+ const void *q;
+ int r;
+
+ assert(p);
+ assert(d);
+
+ r = dns_packet_read(p, sz, &q, start);
+ if (r < 0)
+ return r;
+
+ memcpy(d, q, sz);
+ return 0;
+}
+
int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start) {
const void *d;
int r;
if (r < 0)
goto fail;
+ if (key->class == DNS_CLASS_ANY ||
+ key->type == DNS_TYPE_ANY) {
+ r = -EBADMSG;
+ goto fail;
+ }
+
rr = dns_resource_record_new(key);
if (!rr) {
r = -ENOMEM;
case DNS_TYPE_PTR:
case DNS_TYPE_NS:
case DNS_TYPE_CNAME:
+ case DNS_TYPE_DNAME:
r = dns_packet_read_name(p, &rr->ptr.name, NULL);
break;
r = dns_packet_read_string(p, &rr->hinfo.os, NULL);
break;
- case DNS_TYPE_A:
- r = dns_packet_read(p, sizeof(struct in_addr), &d, NULL);
- if (r < 0)
- goto fail;
+ case DNS_TYPE_SPF: /* exactly the same as TXT */
+ case DNS_TYPE_TXT: {
+ char *s;
+
+ while (p->rindex < offset + rdlength) {
+ r = dns_packet_read_string(p, &s, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = strv_consume(&rr->txt.strings, s);
+ if (r < 0)
+ goto fail;
+ };
+ break;
+ }
- memcpy(&rr->a.in_addr, d, sizeof(struct in_addr));
+ case DNS_TYPE_A:
+ r = dns_packet_read_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL);
break;
case DNS_TYPE_AAAA:
- r = dns_packet_read(p, sizeof(struct in6_addr), &d, NULL);
- if (r < 0)
- goto fail;
-
- memcpy(&rr->aaaa.in6_addr, d, sizeof(struct in6_addr));
+ r = dns_packet_read_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL);
break;
case DNS_TYPE_SOA:
r = dns_packet_read_uint32(p, &rr->soa.minimum, NULL);
break;
+ case DNS_TYPE_MX:
+ r = dns_packet_read_uint16(p, &rr->mx.priority, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_read_name(p, &rr->mx.exchange, NULL);
+ break;
+
+ case DNS_TYPE_LOC: {
+ uint8_t t;
+ size_t pos;
+
+ r = dns_packet_read_uint8(p, &t, &pos);
+ if (r < 0)
+ goto fail;
+
+ if (t == 0) {
+ rr->loc.version = t;
+
+ r = dns_packet_read_uint8(p, &rr->loc.size, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_read_uint8(p, &rr->loc.horiz_pre, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_read_uint8(p, &rr->loc.vert_pre, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_read_uint32(p, &rr->loc.latitude, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_read_uint32(p, &rr->loc.longitude, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = dns_packet_read_uint32(p, &rr->loc.altitude, NULL);
+ if (r < 0)
+ goto fail;
+
+ break;
+ } else {
+ dns_packet_rewind(p, pos);
+ rr->unparseable = true;
+ /* fall through */
+ }
+ }
+
+ case DNS_TYPE_SRV:
+ case DNS_TYPE_SSHFP:
default:
r = dns_packet_read(p, rdlength, &d, NULL);
if (r < 0)