src/resolve/resolved-dns-stream.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include "sd-event.h"
   5
   6 #include "ordered-set.h"
   7 #include "socket-util.h"
   8
   9 typedef struct DnsServer DnsServer;
  10 typedef struct DnsStream DnsStream;
  11 typedef struct DnsTransaction DnsTransaction;
  12 typedef struct Manager Manager;
  13 typedef struct DnsStubListenerExtra DnsStubListenerExtra;
  14
  15 #include "resolved-dns-packet.h"
  16 #include "resolved-dnstls.h"
  17
  18 /* Various timeouts for establishing TCP connections. First the default time-out for that. */
  19 #define DNS_STREAM_DEFAULT_TIMEOUT_USEC (10 * USEC_PER_SEC)
  20
  21 /* In the DNS stub, be more friendly for incoming connections, than we are to ourselves for outgoing ones */
  22 #define DNS_STREAM_STUB_TIMEOUT_USEC (30 * USEC_PER_SEC)
  23
  24 /* In opportunistic TLS mode, lower timeouts */
  25 #define DNS_STREAM_OPPORTUNISTIC_TLS_TIMEOUT_USEC (3 * USEC_PER_SEC)
  26
  27 /* Once connections are established apply this timeout once nothing happens anymore */
  28 #define DNS_STREAM_ESTABLISHED_TIMEOUT_USEC (10 * USEC_PER_SEC)
  29
  30 typedef enum DnsStreamType {
  31         DNS_STREAM_LOOKUP,        /* Outgoing connection to a classic DNS server */
  32         DNS_STREAM_LLMNR_SEND,    /* Outgoing LLMNR TCP lookup */
  33         DNS_STREAM_LLMNR_RECV,    /* Incoming LLMNR TCP lookup */
  34         DNS_STREAM_STUB,          /* Incoming DNS stub connection */
  35         _DNS_STREAM_TYPE_MAX,
  36         _DNS_STREAM_TYPE_INVALID = -EINVAL,
  37 } DnsStreamType;
  38
  39 #define DNS_STREAM_WRITE_TLS_DATA 1
  40
  41 /* Streams are used by three subsystems:
  42  *
  43  *   1. The normal transaction logic when doing a DNS or LLMNR lookup via TCP
  44  *   2. The LLMNR logic when accepting a TCP-based lookup
  45  *   3. The DNS stub logic when accepting a TCP-based lookup
  46  */
  47
  48 struct DnsStream {
  49         Manager *manager;
  50         unsigned n_ref;
  51
  52         DnsStreamType type;
  53         DnsProtocol protocol;
  54
  55         int fd;
  56         union sockaddr_union peer;
  57         socklen_t peer_salen;
  58         union sockaddr_union local;
  59         socklen_t local_salen;
  60         int ifindex;
  61         uint32_t ttl;
  62         bool identified;
  63         bool packet_received; /* At least one packet is received. Used by LLMNR. */
  64         uint32_t requested_events;
  65
  66         /* only when using TCP fast open */
  67         union sockaddr_union tfo_address;
  68         socklen_t tfo_salen;
  69
  70 #if ENABLE_DNS_OVER_TLS
  71         DnsTlsStreamData dnstls_data;
  72         uint32_t dnstls_events;
  73 #endif
  74
  75         sd_event_source *io_event_source;
  76         sd_event_source *timeout_event_source;
  77
  78         be16_t write_size, read_size;
  79         DnsPacket *write_packet, *read_packet;
  80         size_t n_written, n_read;
  81         OrderedSet *write_queue;
  82
  83         int (*on_packet)(DnsStream *s, DnsPacket *p);
  84         int (*complete)(DnsStream *s, int error);
  85
  86         LIST_HEAD(DnsTransaction, transactions); /* when used by the transaction logic */
  87         DnsServer *server;                       /* when used by the transaction logic */
  88         Set *queries;                            /* when used by the DNS stub logic */
  89
  90         /* used when DNS-over-TLS is enabled */
  91         bool encrypted:1;
  92
  93         DnsStubListenerExtra *stub_listener_extra;
  94
  95         LIST_FIELDS(DnsStream, streams);
  96 };
  97
  98 int dns_stream_new(
  99                 Manager *m,
 100                 DnsStream **ret,
 101                 DnsStreamType type,
 102                 DnsProtocol protocol,
 103                 int fd,
 104                 const union sockaddr_union *tfo_address,
 105                 int (on_packet)(DnsStream*, DnsPacket*),
 106                 int (complete)(DnsStream*, int), /* optional */
 107                 usec_t connect_timeout_usec);
 108 #if ENABLE_DNS_OVER_TLS
 109 int dns_stream_connect_tls(DnsStream *s, void *tls_session);
 110 #endif
 111 DnsStream *dns_stream_unref(DnsStream *s);
 112 DnsStream *dns_stream_ref(DnsStream *s);
 113
 114 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsStream*, dns_stream_unref);
 115
 116 int dns_stream_write_packet(DnsStream *s, DnsPacket *p);
 117 ssize_t dns_stream_writev(DnsStream *s, const struct iovec *iov, size_t iovcnt, int flags);
 118
 119 static inline bool DNS_STREAM_QUEUED(DnsStream *s) {
 120         assert(s);
 121
 122         if (s->fd < 0) /* already stopped? */
 123                 return false;
 124
 125         return !!s->write_packet;
 126 }
 127
 128 void dns_stream_detach(DnsStream *s);
 129 int dns_stream_disconnect_all(Manager *m);