diff options
| -rw-r--r-- | src/resolve/resolved-dns-packet.c | 35 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-packet.h | 4 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-scope.c | 93 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-scope.h | 6 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-server.c | 28 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-server.h | 2 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 115 |
7 files changed, 178 insertions, 105 deletions
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c index c425b89034..5f79701296 100644 --- a/src/resolve/resolved-dns-packet.c +++ b/src/resolve/resolved-dns-packet.c @@ -58,6 +58,7 @@ int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) { 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; @@ -681,7 +682,7 @@ fail: } /* 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; @@ -689,6 +690,11 @@ int dns_packet_append_opt_rr(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, /* 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 */ @@ -721,6 +727,11 @@ int dns_packet_append_opt_rr(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, 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; @@ -731,6 +742,27 @@ fail: 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; @@ -1046,7 +1078,6 @@ fail: return r; } - int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) { assert(p); diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h index 36da86dee5..a09ace5b75 100644 --- a/src/resolve/resolved-dns-packet.h +++ b/src/resolve/resolved-dns-packet.h @@ -76,6 +76,7 @@ struct DnsPacket { 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; @@ -173,9 +174,10 @@ int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, bool canonica 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); diff --git a/src/resolve/resolved-dns-scope.c b/src/resolve/resolved-dns-scope.c index b29f15d2c0..13be2a3792 100644 --- a/src/resolve/resolved-dns-scope.c +++ b/src/resolve/resolved-dns-scope.c @@ -162,17 +162,15 @@ void dns_scope_packet_lost(DnsScope *s, usec_t usec) { 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; @@ -181,30 +179,13 @@ static int dns_scope_emit_one(DnsScope *s, int fd, DnsServer *server, DnsPacket 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; @@ -215,15 +196,11 @@ static int dns_scope_emit_one(DnsScope *s, int fd, DnsServer *server, DnsPacket 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; @@ -250,6 +227,8 @@ static int dns_scope_emit_one(DnsScope *s, int fd, DnsServer *server, DnsPacket break; case DNS_PROTOCOL_MDNS: + assert(fd < 0); + if (!ratelimit_test(&s->ratelimit)) return -EBUSY; @@ -279,13 +258,13 @@ static int dns_scope_emit_one(DnsScope *s, int fd, DnsServer *server, DnsPacket 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 */ @@ -294,18 +273,24 @@ int dns_scope_emit_udp(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) { 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; @@ -313,32 +298,27 @@ static int dns_scope_socket(DnsScope *s, int type, int family, const union in_ad 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) { @@ -396,21 +376,18 @@ static int dns_scope_socket(DnsScope *s, int type, int family, const union in_ad 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) { @@ -869,7 +846,7 @@ static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata 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"); } diff --git a/src/resolve/resolved-dns-scope.h b/src/resolve/resolved-dns-scope.h index 177e0e32fa..a0676bd30e 100644 --- a/src/resolve/resolved-dns-scope.h +++ b/src/resolve/resolved-dns-scope.h @@ -82,9 +82,9 @@ DnsScope* dns_scope_free(DnsScope *s); 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); diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c index b0db5bbb16..e6e4feeedd 100644 --- a/src/resolve/resolved-dns-server.c +++ b/src/resolve/resolved-dns-server.c @@ -342,6 +342,34 @@ DnsServerFeatureLevel dns_server_possible_features(DnsServer *s) { 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; diff --git a/src/resolve/resolved-dns-server.h b/src/resolve/resolved-dns-server.h index 3011904bfd..638f29548f 100644 --- a/src/resolve/resolved-dns-server.h +++ b/src/resolve/resolved-dns-server.h @@ -104,6 +104,8 @@ void dns_server_packet_lost(DnsServer *s, DnsServerFeatureLevel features, usec_t 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); diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index e708559137..97aceae381 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -308,6 +308,27 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { 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; @@ -344,7 +365,9 @@ static int on_stream_complete(DnsStream *s, int error) { 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 @@ -354,24 +377,31 @@ static int on_stream_complete(DnsStream *s, int error) { } 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; @@ -388,7 +418,7 @@ static int dns_transaction_open_tcp(DnsTransaction *t) { 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; @@ -403,7 +433,6 @@ static int dns_transaction_open_tcp(DnsTransaction *t) { 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); @@ -412,11 +441,6 @@ static int dns_transaction_open_tcp(DnsTransaction *t) { 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; @@ -426,21 +450,13 @@ static int dns_transaction_open_tcp(DnsTransaction *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); @@ -662,7 +678,7 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { } /* 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) { @@ -743,29 +759,44 @@ static int dns_transaction_emit_udp(DnsTransaction *t) { 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; } @@ -802,7 +833,7 @@ static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdat 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) @@ -1084,10 +1115,12 @@ int dns_transaction_go(DnsTransaction *t) { 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; @@ -1152,7 +1185,7 @@ int dns_transaction_go(DnsTransaction *t) { } /* 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); } |