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Diffstat (limited to 'src/resolve/resolved-dns-transaction.c')
-rw-r--r--src/resolve/resolved-dns-transaction.c131
1 files changed, 121 insertions, 10 deletions
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index 3f4673df7a..e468f245f7 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -39,6 +39,12 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) {
dns_packet_unref(t->received);
dns_answer_unref(t->cached);
+ sd_event_source_unref(t->dns_ipv4_event_source);
+ sd_event_source_unref(t->dns_ipv6_event_source);
+ safe_close(t->dns_ipv4_fd);
+ safe_close(t->dns_ipv6_fd);
+
+ dns_server_unref(t->server);
dns_stream_free(t->stream);
if (t->scope) {
@@ -88,6 +94,8 @@ int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsQuestion *q) {
if (!t)
return -ENOMEM;
+ t->dns_ipv4_fd = t->dns_ipv6_fd = -1;
+
t->question = dns_question_ref(q);
do
@@ -237,6 +245,7 @@ static int on_stream_complete(DnsStream *s, int error) {
}
static int dns_transaction_open_tcp(DnsTransaction *t) {
+ _cleanup_(dns_server_unrefp) DnsServer *server = NULL;
_cleanup_close_ int fd = -1;
int r;
@@ -246,12 +255,12 @@ static int dns_transaction_open_tcp(DnsTransaction *t) {
return 0;
if (t->scope->protocol == DNS_PROTOCOL_DNS)
- fd = dns_scope_tcp_socket(t->scope, AF_UNSPEC, NULL, 53);
+ fd = dns_scope_tcp_socket(t->scope, AF_UNSPEC, NULL, 53, &server);
else if (t->scope->protocol == DNS_PROTOCOL_LLMNR) {
/* When we already received a query to this (but it was truncated), send to its sender address */
if (t->received)
- fd = dns_scope_tcp_socket(t->scope, t->received->family, &t->received->sender, t->received->sender_port);
+ fd = dns_scope_tcp_socket(t->scope, t->received->family, &t->received->sender, t->received->sender_port, NULL);
else {
union in_addr_union address;
int family = AF_UNSPEC;
@@ -265,7 +274,7 @@ static int dns_transaction_open_tcp(DnsTransaction *t) {
if (r == 0)
return -EINVAL;
- fd = dns_scope_tcp_socket(t->scope, family, &address, LLMNR_PORT);
+ fd = dns_scope_tcp_socket(t->scope, family, &address, LLMNR_PORT, NULL);
}
} else
return -EAFNOSUPPORT;
@@ -285,6 +294,9 @@ static int dns_transaction_open_tcp(DnsTransaction *t) {
return r;
}
+
+ dns_server_unref(t->server);
+ t->server = dns_server_ref(server);
t->received = dns_packet_unref(t->received);
t->stream->complete = on_stream_complete;
t->stream->transaction = t;
@@ -333,10 +345,15 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
if (t->scope->protocol == DNS_PROTOCOL_DNS) {
/* For DNS we are fine with accepting packets on any
- * interface, but the source IP address must be one of
- * a valid DNS server */
+ * interface, but the source IP address must be the
+ * one of the DNS server we queried */
+
+ assert(t->server);
- if (!dns_scope_good_dns_server(t->scope, p->family, &p->sender))
+ if (t->server->family != p->family)
+ return;
+
+ if (!in_addr_equal(p->family, &p->sender, &t->server->address))
return;
if (p->sender_port != 53)
@@ -398,6 +415,11 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
return;
}
+ /* Only consider responses with equivalent query section to the request */
+ if (!dns_question_is_superset(p->question, t->question) ||
+ !dns_question_is_superset(t->question, p->question))
+ dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY);
+
/* According to RFC 4795, section 2.9. only the RRs from the answer section shall be cached */
dns_cache_put(&t->scope->cache, p->question, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0, p->family, &p->sender);
@@ -492,6 +514,7 @@ int dns_transaction_go(DnsTransaction *t) {
}
t->n_attempts++;
+ t->server = dns_server_unref(t->server);
t->received = dns_packet_unref(t->received);
t->cached = dns_answer_unref(t->cached);
t->cached_rcode = 0;
@@ -571,17 +594,20 @@ int dns_transaction_go(DnsTransaction *t) {
* always be made via TCP on LLMNR */
r = dns_transaction_open_tcp(t);
} else {
+ DnsServer *server;
+
/* Try via UDP, and if that fails due to large size try via TCP */
- r = dns_scope_emit(t->scope, t->sent);
- if (r == -EMSGSIZE)
+ r = dns_scope_emit(t->scope, t, t->sent, &server);
+ if (r >= 0)
+ t->server = dns_server_ref(server);
+ else if (r == -EMSGSIZE)
r = dns_transaction_open_tcp(t);
}
if (r == -ESRCH) {
/* No servers to send this to? */
dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS);
return 0;
- }
- if (r < 0) {
+ } else if (r < 0) {
if (t->scope->protocol != DNS_PROTOCOL_DNS) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return 0;
@@ -606,6 +632,91 @@ int dns_transaction_go(DnsTransaction *t) {
return 1;
}
+static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+ _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+ DnsTransaction *t = userdata;
+ int r;
+
+ assert(t);
+ assert(t->scope);
+
+ r = manager_recv(t->scope->manager, fd, DNS_PROTOCOL_DNS, &p);
+ if (r <= 0)
+ return r;
+
+ if (dns_packet_validate_reply(p) > 0 &&
+ DNS_PACKET_ID(p) == t->id) {
+ dns_transaction_process_reply(t, p);
+ } else
+ log_debug("Invalid DNS packet.");
+
+ return 0;
+}
+
+int transaction_dns_ipv4_fd(DnsTransaction *t) {
+ const int one = 1;
+ int r;
+
+ assert(t);
+ assert(t->scope);
+ assert(t->scope->manager);
+
+ if (t->dns_ipv4_fd >= 0)
+ return t->dns_ipv4_fd;
+
+ t->dns_ipv4_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (t->dns_ipv4_fd < 0)
+ return -errno;
+
+ r = setsockopt(t->dns_ipv4_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
+ if (r < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = sd_event_add_io(t->scope->manager->event, &t->dns_ipv4_event_source, t->dns_ipv4_fd, EPOLLIN, on_dns_packet, t);
+ if (r < 0)
+ goto fail;
+
+ return t->dns_ipv4_fd;
+
+fail:
+ t->dns_ipv4_fd = safe_close(t->dns_ipv4_fd);
+ return r;
+}
+
+int transaction_dns_ipv6_fd(DnsTransaction *t) {
+ const int one = 1;
+ int r;
+
+ assert(t);
+ assert(t->scope);
+ assert(t->scope->manager);
+
+ if (t->dns_ipv6_fd >= 0)
+ return t->dns_ipv6_fd;
+
+ t->dns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (t->dns_ipv6_fd < 0)
+ return -errno;
+
+ r = setsockopt(t->dns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
+ if (r < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = sd_event_add_io(t->scope->manager->event, &t->dns_ipv6_event_source, t->dns_ipv6_fd, EPOLLIN, on_dns_packet, t);
+ if (r < 0)
+ goto fail;
+
+ return t->dns_ipv6_fd;
+
+fail:
+ t->dns_ipv6_fd = safe_close(t->dns_ipv6_fd);
+ return r;
+}
+
static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = {
[DNS_TRANSACTION_NULL] = "null",
[DNS_TRANSACTION_PENDING] = "pending",