p->size = p->rindex = DNS_PACKET_HEADER_SIZE;
p->allocated = a;
p->protocol = protocol;
+ p->opt_start = p->opt_size = (size_t) -1;
p->n_ref = 1;
*ret = p;
}
/* Append the OPT pseudo-RR described in RFC6891 */
-int dns_packet_append_opt_rr(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start) {
+int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start) {
size_t saved_size;
int r;
/* we must never advertise supported packet size smaller than the legacy max */
assert(max_udp_size >= DNS_PACKET_UNICAST_SIZE_MAX);
+ if (p->opt_start != (size_t) -1)
+ return -EBUSY;
+
+ assert(p->opt_size == (size_t) -1);
+
saved_size = p->size;
/* empty name */
if (r < 0)
goto fail;
+ DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) + 1);
+
+ p->opt_start = saved_size;
+ p->opt_size = p->size - saved_size;
+
if (start)
*start = saved_size;
return r;
}
+int dns_packet_truncate_opt(DnsPacket *p) {
+ assert(p);
+
+ if (p->opt_start == (size_t) -1) {
+ assert(p->opt_size == (size_t) -1);
+ return 0;
+ }
+
+ assert(p->opt_size != (size_t) -1);
+ assert(DNS_PACKET_ARCOUNT(p) > 0);
+
+ if (p->opt_start + p->opt_size != p->size)
+ return -EBUSY;
+
+ dns_packet_truncate(p, p->opt_start);
+ DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) - 1);
+ p->opt_start = p->opt_size = (size_t) -1;
+
+ return 1;
+}
+
int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start) {
size_t saved_size, rdlength_offset, end, rdlength, rds;
int r;
return r;
}
-
int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) {
assert(p);
size_t size, allocated, rindex;
void *_data; /* don't access directly, use DNS_PACKET_DATA()! */
Hashmap *names; /* For name compression */
+ size_t opt_start, opt_size;
/* Parsed data */
DnsQuestion *question;
int dns_packet_append_name(DnsPacket *p, const char *name, bool allow_compression, bool canonical_candidate, size_t *start);
int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *key, size_t *start);
int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start);
-int dns_packet_append_opt_rr(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start);
+int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start);
void dns_packet_truncate(DnsPacket *p, size_t sz);
+int dns_packet_truncate_opt(DnsPacket *p);
int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start);
int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start);
s->resend_timeout = MIN(s->resend_timeout * 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC);
}
-static int dns_scope_emit_one(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
+static int dns_scope_emit_one(DnsScope *s, int fd, DnsPacket *p) {
union in_addr_union addr;
int ifindex = 0, r;
int family;
uint32_t mtu;
- size_t saved_size = 0;
assert(s);
assert(p);
assert(p->protocol == s->protocol);
- assert((s->protocol == DNS_PROTOCOL_DNS) != (fd < 0));
if (s->link) {
mtu = s->link->mtu;
mtu = manager_find_mtu(s->manager);
switch (s->protocol) {
+
case DNS_PROTOCOL_DNS:
- assert(server);
+ assert(fd >= 0);
if (DNS_PACKET_QDCOUNT(p) > 1)
return -EOPNOTSUPP;
- if (server->possible_features >= DNS_SERVER_FEATURE_LEVEL_EDNS0) {
- bool edns_do;
- size_t packet_size;
-
- edns_do = server->possible_features >= DNS_SERVER_FEATURE_LEVEL_DO;
-
- if (server->possible_features >= DNS_SERVER_FEATURE_LEVEL_LARGE)
- packet_size = DNS_PACKET_UNICAST_SIZE_LARGE_MAX;
- else
- packet_size = server->received_udp_packet_max;
-
- r = dns_packet_append_opt_rr(p, packet_size, edns_do, &saved_size);
- if (r < 0)
- return r;
-
- DNS_PACKET_HEADER(p)->arcount = htobe16(be16toh(DNS_PACKET_HEADER(p)->arcount) + 1);
- }
-
if (p->size > DNS_PACKET_UNICAST_SIZE_MAX)
return -EMSGSIZE;
if (r < 0)
return r;
- if (saved_size > 0) {
- dns_packet_truncate(p, saved_size);
-
- DNS_PACKET_HEADER(p)->arcount = htobe16(be16toh(DNS_PACKET_HEADER(p)->arcount) - 1);
- }
-
break;
case DNS_PROTOCOL_LLMNR:
+ assert(fd < 0);
+
if (DNS_PACKET_QDCOUNT(p) > 1)
return -EOPNOTSUPP;
break;
case DNS_PROTOCOL_MDNS:
+ assert(fd < 0);
+
if (!ratelimit_test(&s->ratelimit))
return -EBUSY;
return 1;
}
-int dns_scope_emit_udp(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
+int dns_scope_emit_udp(DnsScope *s, int fd, DnsPacket *p) {
int r;
assert(s);
assert(p);
assert(p->protocol == s->protocol);
- assert((s->protocol == DNS_PROTOCOL_DNS) != (fd < 0));
+ assert((s->protocol == DNS_PROTOCOL_DNS) == (fd >= 0));
do {
/* If there are multiple linked packets, set the TC bit in all but the last of them */
dns_packet_set_flags(p, true, true);
}
- r = dns_scope_emit_one(s, fd, server, p);
+ r = dns_scope_emit_one(s, fd, p);
if (r < 0)
return r;
p = p->more;
- } while(p);
+ } while (p);
return 0;
}
-static int dns_scope_socket(DnsScope *s, int type, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) {
- DnsServer *srv = NULL;
+static int dns_scope_socket(
+ DnsScope *s,
+ int type,
+ int family,
+ const union in_addr_union *address,
+ DnsServer *server,
+ uint16_t port) {
+
_cleanup_close_ int fd = -1;
union sockaddr_union sa = {};
socklen_t salen;
int ret, r;
assert(s);
- assert((family == AF_UNSPEC) == !address);
-
- if (family == AF_UNSPEC) {
- srv = dns_scope_get_dns_server(s);
- if (!srv)
- return -ESRCH;
-
- /* Determine current feature level to use */
- (void) dns_server_possible_features(srv);
- if (type == SOCK_DGRAM && srv->possible_features < DNS_SERVER_FEATURE_LEVEL_UDP)
- return -EAGAIN;
+ if (server) {
+ assert(family == AF_UNSPEC);
+ assert(!address);
- sa.sa.sa_family = srv->family;
- if (srv->family == AF_INET) {
+ sa.sa.sa_family = server->family;
+ if (server->family == AF_INET) {
sa.in.sin_port = htobe16(port);
- sa.in.sin_addr = srv->address.in;
+ sa.in.sin_addr = server->address.in;
salen = sizeof(sa.in);
- } else if (srv->family == AF_INET6) {
+ } else if (server->family == AF_INET6) {
sa.in6.sin6_port = htobe16(port);
- sa.in6.sin6_addr = srv->address.in6;
+ sa.in6.sin6_addr = server->address.in6;
sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0;
salen = sizeof(sa.in6);
} else
return -EAFNOSUPPORT;
} else {
+ assert(family != AF_UNSPEC);
+ assert(address);
+
sa.sa.sa_family = family;
if (family == AF_INET) {
if (r < 0 && errno != EINPROGRESS)
return -errno;
- if (server)
- *server = srv;
-
ret = fd;
fd = -1;
return ret;
}
-int dns_scope_socket_udp(DnsScope *s, DnsServer **server) {
- return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, 53, server);
+int dns_scope_socket_udp(DnsScope *s, DnsServer *server, uint16_t port) {
+ return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, server, port);
}
-int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) {
- return dns_scope_socket(s, SOCK_STREAM, family, address, port, server);
+int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, DnsServer *server, uint16_t port) {
+ return dns_scope_socket(s, SOCK_STREAM, family, address, server, port);
}
DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain) {
return 0;
}
- r = dns_scope_emit_udp(scope, -1, NULL, p);
+ r = dns_scope_emit_udp(scope, -1, p);
if (r < 0)
log_debug_errno(r, "Failed to send conflict packet: %m");
}
void dns_scope_packet_received(DnsScope *s, usec_t rtt);
void dns_scope_packet_lost(DnsScope *s, usec_t usec);
-int dns_scope_emit_udp(DnsScope *s, int fd, DnsServer *server, DnsPacket *p);
-int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, uint16_t port, DnsServer **server);
-int dns_scope_socket_udp(DnsScope *s, DnsServer **server);
+int dns_scope_emit_udp(DnsScope *s, int fd, DnsPacket *p);
+int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, DnsServer *server, uint16_t port);
+int dns_scope_socket_udp(DnsScope *s, DnsServer *server, uint16_t port);
DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain);
int dns_scope_good_key(DnsScope *s, DnsResourceKey *key);
return s->possible_features;
}
+int dns_server_adjust_opt(DnsServer *server, DnsPacket *packet, DnsServerFeatureLevel level) {
+ size_t packet_size;
+ bool edns_do;
+ int r;
+
+ assert(server);
+ assert(packet);
+ assert(packet->protocol == DNS_PROTOCOL_DNS);
+
+ /* Fix the OPT field in the packet to match our current feature level. */
+
+ r = dns_packet_truncate_opt(packet);
+ if (r < 0)
+ return r;
+
+ if (level < DNS_SERVER_FEATURE_LEVEL_EDNS0)
+ return 0;
+
+ edns_do = level >= DNS_SERVER_FEATURE_LEVEL_DO;
+
+ if (level >= DNS_SERVER_FEATURE_LEVEL_LARGE)
+ packet_size = DNS_PACKET_UNICAST_SIZE_LARGE_MAX;
+ else
+ packet_size = server->received_udp_packet_max;
+
+ return dns_packet_append_opt(packet, packet_size, edns_do, NULL);
+}
+
static void dns_server_hash_func(const void *p, struct siphash *state) {
const DnsServer *s = p;
void dns_server_packet_failed(DnsServer *s, DnsServerFeatureLevel features);
void dns_server_packet_rrsig_missing(DnsServer *s);
+int dns_server_adjust_opt(DnsServer *server, DnsPacket *packet, DnsServerFeatureLevel level);
+
DnsServer *dns_server_find(DnsServer *first, int family, const union in_addr_union *in_addr);
void dns_server_unlink_all(DnsServer *first);
dns_transaction_gc(t);
}
+static int dns_transaction_pick_server(DnsTransaction *t) {
+ DnsServer *server;
+
+ assert(t);
+ assert(t->scope->protocol == DNS_PROTOCOL_DNS);
+
+ server = dns_scope_get_dns_server(t->scope);
+ if (!server)
+ return -ESRCH;
+
+ t->current_features = dns_server_possible_features(server);
+
+ if (server == t->server)
+ return 0;
+
+ dns_server_unref(t->server);
+ t->server = dns_server_ref(server);
+
+ return 1;
+}
+
static int on_stream_complete(DnsStream *s, int error) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
DnsTransaction *t;
dns_transaction_process_reply(t, p);
t->block_gc--;
- /* If the response wasn't useful, then complete the transition now */
+ /* If the response wasn't useful, then complete the transition
+ * now. After all, we are the worst feature set now with TCP
+ * sockets, and there's really no point in retrying. */
if (t->state == DNS_TRANSACTION_PENDING)
dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY);
else
}
static int dns_transaction_open_tcp(DnsTransaction *t) {
- DnsServer *server = NULL;
_cleanup_close_ int fd = -1;
int r;
assert(t);
- if (t->stream)
- return 0;
+ dns_transaction_close_connection(t);
switch (t->scope->protocol) {
+
case DNS_PROTOCOL_DNS:
- fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, 53, &server);
+ r = dns_transaction_pick_server(t);
+ if (r < 0)
+ return r;
+
+ r = dns_server_adjust_opt(t->server, t->sent, t->current_features);
+ if (r < 0)
+ return r;
+
+ fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, t->server, 53);
break;
case DNS_PROTOCOL_LLMNR:
/* When we already received a reply to this (but it was truncated), send to its sender address */
if (t->received)
- fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, t->received->sender_port, NULL);
+ fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, NULL, t->received->sender_port);
else {
union in_addr_union address;
int family = AF_UNSPEC;
if (family != t->scope->family)
return -ESRCH;
- fd = dns_scope_socket_tcp(t->scope, family, &address, LLMNR_PORT, NULL);
+ fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT);
}
break;
r = dns_stream_new(t->scope->manager, &t->stream, t->scope->protocol, fd);
if (r < 0)
return r;
-
fd = -1;
r = dns_stream_write_packet(t->stream, t->sent);
return r;
}
- dns_server_unref(t->server);
- t->server = dns_server_ref(server);
-
- dns_transaction_reset_answer(t);
-
t->stream->complete = on_stream_complete;
t->stream->transaction = t;
if (t->scope->link)
t->stream->ifindex = t->scope->link->ifindex;
+ dns_transaction_reset_answer(t);
+
t->tried_stream = true;
return 0;
}
-static void dns_transaction_next_dns_server(DnsTransaction *t) {
- assert(t);
-
- t->server = dns_server_unref(t->server);
- t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source);
- t->dns_udp_fd = safe_close(t->dns_udp_fd);
-
- dns_scope_next_dns_server(t->scope);
-}
-
static void dns_transaction_cache_answer(DnsTransaction *t) {
assert(t);
}
/* On DNS, couldn't send? Try immediately again, with a new server */
- dns_transaction_next_dns_server(t);
+ dns_scope_next_dns_server(t->scope);
r = dns_transaction_go(t);
if (r < 0) {
assert(t);
- if (t->scope->protocol == DNS_PROTOCOL_DNS && !t->server) {
- DnsServer *server = NULL;
- _cleanup_close_ int fd = -1;
-
- fd = dns_scope_socket_udp(t->scope, &server);
- if (fd < 0)
- return fd;
+ if (t->scope->protocol == DNS_PROTOCOL_DNS) {
- r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t);
+ r = dns_transaction_pick_server(t);
if (r < 0)
return r;
- t->dns_udp_fd = fd;
- fd = -1;
- t->server = dns_server_ref(server);
- }
+ if (t->current_features < DNS_SERVER_FEATURE_LEVEL_UDP)
+ return -EAGAIN;
+
+ if (r > 0 || t->dns_udp_fd < 0) { /* Server changed, or no connection yet. */
+ int fd;
+
+ dns_transaction_close_connection(t);
- r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->server, t->sent);
+ fd = dns_scope_socket_udp(t->scope, t->server, 53);
+ if (fd < 0)
+ return fd;
+
+ r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t);
+ if (r < 0) {
+ safe_close(fd);
+ return r;
+ }
+
+ t->dns_udp_fd = fd;
+ }
+
+ r = dns_server_adjust_opt(t->server, t->sent, t->current_features);
+ if (r < 0)
+ return r;
+ } else
+ dns_transaction_close_connection(t);
+
+ r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->sent);
if (r < 0)
return r;
- if (t->server)
- t->current_features = t->server->possible_features;
+ dns_transaction_reset_answer(t);
return 0;
}
log_debug("Timeout reached on transaction %" PRIu16 ".", t->id);
/* ...and try again with a new server */
- dns_transaction_next_dns_server(t);
+ dns_scope_next_dns_server(t->scope);
r = dns_transaction_go(t);
if (r < 0)
random_bytes(&jitter, sizeof(jitter));
switch (t->scope->protocol) {
+
case DNS_PROTOCOL_LLMNR:
jitter %= LLMNR_JITTER_INTERVAL_USEC;
accuracy = LLMNR_JITTER_INTERVAL_USEC;
break;
+
case DNS_PROTOCOL_MDNS:
jitter %= MDNS_JITTER_RANGE_USEC;
jitter += MDNS_JITTER_MIN_USEC;
}
/* Couldn't send? Try immediately again, with a new server */
- dns_transaction_next_dns_server(t);
+ dns_scope_next_dns_server(t->scope);
return dns_transaction_go(t);
}
projects / thirdparty / systemd.git / commitdiff
