/*~ Welcome to the connect daemon: maintainer of connectivity! * * This is another separate daemon which is responsible for reaching out to * other peers, and also accepting their incoming connections. It talks to * them for just long enough to validate their identity using a cryptographic * handshake, then receive and send supported feature sets; then it hands them * up to lightningd which will fire up a specific per-peer daemon to talk to * it. */ #include "config.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /*~ We are passed two file descriptors when exec'ed from `lightningd`: the * first is a connection to `hsmd`, which we need for the cryptographic * handshake, and the second is to `gossipd`: it gathers network gossip and * thus may know how to reach certain peers. */ #define HSM_FD 3 #define GOSSIPCTL_FD 4 /*~ In C convention, constants are UPPERCASE macros. Not everything needs to * be a constant, but it soothes the programmer's conscience to encapsulate * arbitrary decisions like these in one place. */ #define MAX_CONNECT_ATTEMPTS 10 #define INITIAL_WAIT_SECONDS 1 #define MAX_WAIT_SECONDS 300 /* Peers we're trying to reach: we iterate through addrs until we succeed * or fail. */ struct connecting { /* daemon->connecting */ struct list_node list; struct daemon *daemon; struct io_conn *conn; /* The ID of the peer (not necessarily unique, in transit!) */ struct node_id id; /* We iterate through the tal_count(addrs) */ size_t addrnum; struct wireaddr_internal *addrs; /* NULL if there wasn't a hint. */ struct wireaddr_internal *addrhint; /* How far did we get? */ const char *connstate; /* Accumulated errors */ char *errors; /* How many seconds did we wait this time? */ u32 seconds_waited; }; /*~ C programs should generally be written bottom-to-top, with the root * function at the bottom, and functions it calls above it. That avoids * us having to pre-declare functions; but in the case of mutual recursion * pre-declarations are necessary (also, sometimes we do it to avoid making * a patch hard to review with gratuitous reorganizations). */ static void try_connect_one_addr(struct connecting *connect); /*~ Some ISP resolvers will reply with a dummy IP to queries that would otherwise * result in an NXDOMAIN reply. This just checks whether we have one such * resolver upstream and remembers its reply so we can try to filter future * dummies out. */ static bool broken_resolver(struct daemon *daemon) { struct addrinfo *addrinfo; struct addrinfo hints; const char *hostname = "nxdomain-test.doesntexist"; int err; /* If they told us to never do DNS queries, don't even do this one and * also not if we just say that we don't */ if (!daemon->use_dns || daemon->always_use_proxy) { daemon->broken_resolver_response = NULL; return false; } memset(&hints, 0, sizeof(hints)); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = 0; hints.ai_flags = AI_ADDRCONFIG; err = getaddrinfo(hostname, tal_fmt(tmpctx, "%d", 42), &hints, &addrinfo); /*~ Note the use of tal_dup here: it is a memdup for tal, but it's * type-aware so it's less error-prone. */ if (err == 0) { daemon->broken_resolver_response = tal_dup(daemon, struct sockaddr, addrinfo->ai_addr); freeaddrinfo(addrinfo); } else daemon->broken_resolver_response = NULL; return daemon->broken_resolver_response != NULL; } /*~ Here we see our first tal destructor: in this case the 'struct connect' * simply removes itself from the list of all 'connect' structs. */ static void destroy_connecting(struct connecting *connect) { /*~ We don't *need* the list_head here; `list_del(&connect->list)` * would work. But we have access to it, and `list_del_from()` is * clearer for readers, and also does a very brief sanity check that * the list isn't already empty which catches a surprising number of * bugs! (If CCAN_LIST_DEBUG were defined, it would perform a * complete list traverse to check it was in the list before * deletion). */ list_del_from(&connect->daemon->connecting, &connect->list); } /*~ Most simple search functions start with find_; in this case, search * for an existing attempt to connect the given peer id. */ static struct connecting *find_connecting(struct daemon *daemon, const struct node_id *id) { struct connecting *i; /*~ Note the node_id_eq function: this is generally preferred over * doing a memcmp() manually, as it is both typesafe and can handle * any padding which the C compiler is allowed to insert between * members (unnecessary here, as there's no padding in a `struct * node_id`). */ list_for_each(&daemon->connecting, i, list) if (node_id_eq(id, &i->id)) return i; return NULL; } /*~ Once we've connected out, we disable the callback which would cause us to * to try the next address. */ static void connected_out_to_peer(struct daemon *daemon, struct io_conn *conn, const struct node_id *id) { struct connecting *connect = find_connecting(daemon, id); /* We allocate 'conn' as a child of 'connect': we don't want to free * it just yet though. tal_steal() it onto the permanent 'daemon' * struct. */ tal_steal(daemon, conn); /* We only allow one outgoing attempt at a time */ assert(connect->conn == conn); /* Don't call destroy_io_conn, since we're done. */ io_set_finish(conn, NULL, NULL); /* Now free the 'connecting' struct. */ tal_free(connect); } /*~ Once they've connected in, stop trying to connect out (if we were). */ static void peer_connected_in(struct daemon *daemon, struct io_conn *conn, const struct node_id *id) { struct connecting *connect = find_connecting(daemon, id); if (!connect) return; /* Don't call destroy_io_conn, since we're done. */ io_set_finish(connect->conn, NULL, NULL); /* Now free the 'connecting' struct since we succeeded. */ tal_free(connect); } /*~ When we free a peer, we remove it from the daemon's hashtable. * We also call this manually if we want to elegantly drain peer's * queues. */ void destroy_peer(struct peer *peer) { assert(!peer->draining); if (!peer_htable_del(&peer->daemon->peers, peer)) abort(); /* Tell gossipd to stop asking this peer gossip queries */ daemon_conn_send(peer->daemon->gossipd, take(towire_gossipd_peer_gone(NULL, &peer->id))); /* Tell lightningd it's really disconnected */ daemon_conn_send(peer->daemon->master, take(towire_connectd_peer_disconnect_done(NULL, &peer->id, peer->counter))); /* This makes multiplex.c routines not feed us more, but * *also* means that if we're freed directly, the ->to_peer * destructor won't call drain_peer(). */ peer->draining = true; } /*~ This is where we create a new peer. */ static struct peer *new_peer(struct daemon *daemon, const struct node_id *id, const struct crypto_state *cs, const u8 *their_features, struct io_conn *conn STEALS, int *fd_for_subd) { struct peer *peer = tal(daemon, struct peer); peer->daemon = daemon; peer->id = *id; peer->counter = daemon->connection_counter++; peer->cs = *cs; peer->subds = tal_arr(peer, struct subd *, 0); peer->peer_in = NULL; peer->sent_to_peer = NULL; peer->urgent = false; peer->draining = false; peer->peer_outq = msg_queue_new(peer, false); peer->last_recv_time = time_now(); #if DEVELOPER peer->dev_writes_enabled = NULL; peer->dev_read_enabled = true; #endif peer->to_peer = conn; /* Now we own it */ tal_steal(peer, peer->to_peer); peer_htable_add(&daemon->peers, peer); tal_add_destructor(peer, destroy_peer); return peer; } /*~ Note the lack of static: this is called by peer_exchange_initmsg.c once the * INIT messages are exchanged, and also by the retry code above. */ struct io_plan *peer_connected(struct io_conn *conn, struct daemon *daemon, const struct node_id *id, const struct wireaddr_internal *addr, const struct wireaddr *remote_addr, struct crypto_state *cs, const u8 *their_features TAKES, bool incoming) { u8 *msg; struct peer *peer; int unsup; size_t depender, missing; int subd_fd; bool option_gossip_queries; /* We remove any previous connection immediately, on the assumption it's dead */ peer = peer_htable_get(&daemon->peers, id); if (peer) tal_free(peer); /* We promised we'd take it by marking it TAKEN above; prepare to free it. */ if (taken(their_features)) tal_steal(tmpctx, their_features); /* BOLT #1: * * The receiving node: * ... * - upon receiving unknown _odd_ feature bits that are non-zero: * - MUST ignore the bit. * - upon receiving unknown _even_ feature bits that are non-zero: * - MUST close the connection. */ unsup = features_unsupported(daemon->our_features, their_features, INIT_FEATURE); if (unsup != -1) { status_peer_unusual(id, "Unsupported feature %u", unsup); msg = towire_warningfmt(NULL, NULL, "Unsupported feature %u", unsup); msg = cryptomsg_encrypt_msg(tmpctx, cs, take(msg)); return io_write(conn, msg, tal_count(msg), io_close_cb, NULL); } if (!feature_check_depends(their_features, &depender, &missing)) { status_peer_unusual(id, "Feature %zu requires feature %zu", depender, missing); msg = towire_warningfmt(NULL, NULL, "Feature %zu requires feature %zu", depender, missing); msg = cryptomsg_encrypt_msg(tmpctx, cs, take(msg)); return io_write(conn, msg, tal_count(msg), io_close_cb, NULL); } /* We've successfully connected. */ if (incoming) peer_connected_in(daemon, conn, id); else connected_out_to_peer(daemon, conn, id); if (find_connecting(daemon, id)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "After %s connection on %p, still trying to connect conn %p?", incoming ? "incoming" : "outgoing", conn, find_connecting(daemon, id)->conn); /* This contains the per-peer state info; gossipd fills in pps->gs */ peer = new_peer(daemon, id, cs, their_features, conn, &subd_fd); /* Only takes over conn if it succeeds. */ if (!peer) return io_close(conn); /* Tell gossipd it can ask query this new peer for gossip */ option_gossip_queries = feature_negotiated(daemon->our_features, their_features, OPT_GOSSIP_QUERIES); msg = towire_gossipd_new_peer(NULL, id, option_gossip_queries); daemon_conn_send(daemon->gossipd, take(msg)); /* Get ready for streaming gossip from the store */ setup_peer_gossip_store(peer, daemon->our_features, their_features); /* Create message to tell master peer has connected. */ msg = towire_connectd_peer_connected(NULL, id, peer->counter, addr, remote_addr, incoming, their_features); /*~ daemon_conn is a message queue for inter-daemon communication: we * queue up the `connect_peer_connected` message to tell lightningd * we have connected. Once it says something interesting, we tell * it that, too. */ daemon_conn_send(daemon->master, take(msg)); /*~ Now we set up this connection to read/write from subd */ return multiplex_peer_setup(conn, peer); } /*~ handshake.c's handles setting up the crypto state once we get a connection * in; we hand it straight to peer_exchange_initmsg() to send and receive INIT * and call peer_connected(). */ static struct io_plan *handshake_in_success(struct io_conn *conn, const struct pubkey *id_key, const struct wireaddr_internal *addr, struct crypto_state *cs, struct oneshot *timeout, struct daemon *daemon) { struct node_id id; node_id_from_pubkey(&id, id_key); status_peer_debug(&id, "Connect IN"); return peer_exchange_initmsg(conn, daemon, daemon->our_features, cs, &id, addr, timeout, true); } /*~ If the timer goes off, we simply free everything, which hangs up. */ static void conn_timeout(struct io_conn *conn) { status_debug("conn timed out"); errno = ETIMEDOUT; io_close(conn); } /*~ So, where are you from? */ static bool get_remote_address(struct io_conn *conn, struct wireaddr_internal *addr) { struct sockaddr_storage s = {}; socklen_t len = sizeof(s); /* The cast here is a weird Berkeley sockets API feature... */ if (getpeername(io_conn_fd(conn), (struct sockaddr *)&s, &len) != 0) { status_debug("Failed to get peername for incoming conn: %s", strerror(errno)); return false; } if (s.ss_family == AF_INET6) { struct sockaddr_in6 *s6 = (void *)&s; addr->itype = ADDR_INTERNAL_WIREADDR; wireaddr_from_ipv6(&addr->u.wireaddr, &s6->sin6_addr, ntohs(s6->sin6_port)); } else if (s.ss_family == AF_INET) { struct sockaddr_in *s4 = (void *)&s; addr->itype = ADDR_INTERNAL_WIREADDR; wireaddr_from_ipv4(&addr->u.wireaddr, &s4->sin_addr, ntohs(s4->sin_port)); } else if (s.ss_family == AF_UNIX) { struct sockaddr_un *sun = (void *)&s; addr->itype = ADDR_INTERNAL_SOCKNAME; memcpy(addr->u.sockname, sun->sun_path, sizeof(sun->sun_path)); } else { status_broken("Unknown socket type %i for incoming conn", s.ss_family); return false; } return true; } /*~ As so common in C, we need to bundle two args into a callback, so we * allocate a temporary structure to hold them: */ struct conn_in { struct wireaddr_internal addr; struct daemon *daemon; }; /*~ Once we've got a connection in, we set it up here (whether it's via the * websocket proxy, or direct). */ static struct io_plan *conn_in(struct io_conn *conn, struct conn_in *conn_in_arg) { struct daemon *daemon = conn_in_arg->daemon; struct oneshot *timeout; /* If they don't complete handshake in reasonable time, we hang up */ timeout = new_reltimer(&daemon->timers, conn, time_from_sec(daemon->timeout_secs), conn_timeout, conn); /*~ The crypto handshake differs depending on whether you received or * initiated the socket connection, so there are two entry points. * Note, again, the notleak() to avoid our simplistic leak detection * code from thinking `conn` (which we don't keep a pointer to) is * leaked */ return responder_handshake(notleak(conn), &daemon->mykey, &conn_in_arg->addr, timeout, handshake_in_success, daemon); } /*~ When we get a direct connection in we set up its network address * then call handshake.c to set up the crypto state. */ static struct io_plan *connection_in(struct io_conn *conn, struct daemon *daemon) { struct conn_in conn_in_arg; if (!get_remote_address(conn, &conn_in_arg.addr)) return io_close(conn); conn_in_arg.daemon = daemon; return conn_in(conn, &conn_in_arg); } /*~ I speak web socket. * * Actually that's dumb, websocket (aka rfc6455) looks nothing like that. */ static struct io_plan *websocket_connection_in(struct io_conn *conn, struct daemon *daemon) { int childmsg[2], execfail[2]; pid_t childpid; int err; struct conn_in conn_in_arg; if (!get_remote_address(conn, &conn_in_arg.addr)) return io_close(conn); status_debug("Websocket connection in from %s", type_to_string(tmpctx, struct wireaddr_internal, &conn_in_arg.addr)); if (socketpair(AF_LOCAL, SOCK_STREAM, 0, childmsg) != 0) goto fail; if (pipe(execfail) != 0) goto close_msgfd_fail; if (fcntl(execfail[1], F_SETFD, fcntl(execfail[1], F_GETFD) | FD_CLOEXEC) < 0) goto close_execfail_fail; childpid = fork(); if (childpid < 0) goto close_execfail_fail; if (childpid == 0) { close(childmsg[0]); close(execfail[0]); /* Attach remote socket to stdin. */ if (dup2(io_conn_fd(conn), STDIN_FILENO) == -1) goto child_errno_fail; /* Attach our socket to stdout. */ if (dup2(childmsg[1], STDOUT_FILENO) == -1) goto child_errno_fail; /* Make (fairly!) sure all other fds are closed. */ closefrom(STDERR_FILENO + 1); /* Tell websocket helper what we read so far. */ execlp(daemon->websocket_helper, daemon->websocket_helper, NULL); child_errno_fail: err = errno; /* Gcc's warn-unused-result fail. */ if (write(execfail[1], &err, sizeof(err))) { ; } exit(127); } close(childmsg[1]); close(execfail[1]); /* Child will close this without writing on successful exec. */ if (read(execfail[0], &err, sizeof(err)) == sizeof(err)) { close(execfail[0]); waitpid(childpid, NULL, 0); status_broken("Exec of helper %s failed: %s", daemon->websocket_helper, strerror(err)); errno = err; return io_close(conn); } close(execfail[0]); /* New connection actually talks to proxy process. */ conn_in_arg.daemon = daemon; io_new_conn(tal_parent(conn), childmsg[0], conn_in, &conn_in_arg); /* Abandon original (doesn't close since child has dup'd fd) */ return io_close(conn); close_execfail_fail: close_noerr(execfail[0]); close_noerr(execfail[1]); close_msgfd_fail: close_noerr(childmsg[0]); close_noerr(childmsg[1]); fail: status_broken("Preparation of helper failed: %s", strerror(errno)); return io_close(conn); } /*~ These are the mirror functions for the connecting-out case. */ static struct io_plan *handshake_out_success(struct io_conn *conn, const struct pubkey *key, const struct wireaddr_internal *addr, struct crypto_state *cs, struct oneshot *timeout, struct connecting *connect) { struct node_id id; node_id_from_pubkey(&id, key); connect->connstate = "Exchanging init messages"; status_peer_debug(&id, "Connect OUT"); return peer_exchange_initmsg(conn, connect->daemon, connect->daemon->our_features, cs, &id, addr, timeout, false); } struct io_plan *connection_out(struct io_conn *conn, struct connecting *connect) { struct pubkey outkey; struct oneshot *timeout; /* This shouldn't happen: lightningd should not give invalid ids! */ if (!pubkey_from_node_id(&outkey, &connect->id)) { status_broken("Connection out to invalid id %s", type_to_string(tmpctx, struct node_id, &connect->id)); return io_close(conn); } /* If they don't complete handshake in reasonable time, hang up */ timeout = new_reltimer(&connect->daemon->timers, conn, time_from_sec(connect->daemon->timeout_secs), conn_timeout, conn); status_peer_debug(&connect->id, "Connected out, starting crypto"); connect->connstate = "Cryptographic handshake"; return initiator_handshake(conn, &connect->daemon->mykey, &outkey, &connect->addrs[connect->addrnum], timeout, handshake_out_success, connect); } /*~ When we've exhausted all addresses without success, we come here. * * Note that gcc gets upset if we put the PRINTF_FMT at the end like this if * it's an actual function definition, but etags gets confused and ignores the * rest of the file if we put PRINTF_FMT at the front. So we put it at the * end, in a gratuitous declaration. */ static void connect_failed(struct daemon *daemon, const struct node_id *id, u32 seconds_waited, const struct wireaddr_internal *addrhint, errcode_t errcode, const char *errfmt, ...) PRINTF_FMT(6,7); static void connect_failed(struct daemon *daemon, const struct node_id *id, u32 seconds_waited, const struct wireaddr_internal *addrhint, errcode_t errcode, const char *errfmt, ...) { u8 *msg; va_list ap; char *errmsg; u32 wait_seconds; va_start(ap, errfmt); errmsg = tal_vfmt(tmpctx, errfmt, ap); va_end(ap); /* Wait twice as long to reconnect, between min and max. */ wait_seconds = seconds_waited * 2; if (wait_seconds > MAX_WAIT_SECONDS) wait_seconds = MAX_WAIT_SECONDS; if (wait_seconds < INITIAL_WAIT_SECONDS) wait_seconds = INITIAL_WAIT_SECONDS; /* lightningd may have a connect command waiting to know what * happened. We leave it to lightningd to decide if it wants to try * again, with the wait_seconds as a hint of how long before * asking. */ msg = towire_connectd_connect_failed(NULL, id, errcode, errmsg, wait_seconds, addrhint); daemon_conn_send(daemon->master, take(msg)); status_peer_debug(id, "Failed connected out: %s", errmsg); } /* add errors to error list */ void add_errors_to_error_list(struct connecting *connect, const char *error) { tal_append_fmt(&connect->errors, "%s. ", error); } /*~ This is the destructor for the (unsuccessful) outgoing connection. We accumulate * the errors which occurred, so we can report to lightningd properly in case * they all fail, and try the next address. * * This is a specialized form of destructor which takes an extra argument; * it set up by either the creatively-named tal_add_destructor2(), or by * the ccan/io's io_set_finish() on a connection. */ static void destroy_io_conn(struct io_conn *conn, struct connecting *connect) { /*~ tal_append_fmt appends to a tal string. It's terribly convenient */ const char *errstr = strerror(errno); /* errno 0 means they hung up on us. */ if (errno == 0) { errstr = "peer closed connection"; if (streq(connect->connstate, "Cryptographic handshake")) errstr = "peer closed connection (wrong key?)"; } add_errors_to_error_list(connect, tal_fmt(tmpctx, "%s: %s: %s", type_to_string(tmpctx, struct wireaddr_internal, &connect->addrs[connect->addrnum]), connect->connstate, errstr)); connect->addrnum++; connect->conn = NULL; try_connect_one_addr(connect); } /* This initializes a fresh io_conn by setting it to io_connect to the * destination */ static struct io_plan *conn_init(struct io_conn *conn, struct connecting *connect) { /*~ I generally dislike the pattern of "set to NULL, assert if NULL at * bottom". On -O2 and above the compiler will warn you at compile time * if a there is a path by which the variable is not set, which is always * preferable to a runtime assertion. In this case, it's the best way * to use the "enum in a switch" trick to make sure we handle all enum * cases, so I use it. */ struct addrinfo *ai = NULL; const struct wireaddr_internal *addr = &connect->addrs[connect->addrnum]; switch (addr->itype) { case ADDR_INTERNAL_SOCKNAME: ai = wireaddr_internal_to_addrinfo(tmpctx, addr); break; case ADDR_INTERNAL_ALLPROTO: status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't connect to all protocols"); break; case ADDR_INTERNAL_AUTOTOR: status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't connect to autotor address"); break; case ADDR_INTERNAL_STATICTOR: status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't connect to statictor address"); break; case ADDR_INTERNAL_FORPROXY: status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't connect to forproxy address"); break; case ADDR_INTERNAL_WIREADDR: /* DNS should have been resolved before */ assert(addr->u.wireaddr.type != ADDR_TYPE_DNS); /* If it was a Tor address, we wouldn't be here. */ assert(!is_toraddr((char*)addr->u.wireaddr.addr)); ai = wireaddr_to_addrinfo(tmpctx, &addr->u.wireaddr); break; } assert(ai); io_set_finish(conn, destroy_io_conn, connect); return io_connect(conn, ai, connection_out, connect); } /* This initializes a fresh io_conn by setting it to io_connect to the * SOCKS proxy, as handled in tor.c. */ static struct io_plan *conn_proxy_init(struct io_conn *conn, struct connecting *connect) { const char *host = NULL; u16 port; const struct wireaddr_internal *addr = &connect->addrs[connect->addrnum]; switch (addr->itype) { case ADDR_INTERNAL_FORPROXY: host = addr->u.unresolved.name; port = addr->u.unresolved.port; break; case ADDR_INTERNAL_WIREADDR: host = fmt_wireaddr_without_port(tmpctx, &addr->u.wireaddr); port = addr->u.wireaddr.port; break; case ADDR_INTERNAL_SOCKNAME: case ADDR_INTERNAL_ALLPROTO: case ADDR_INTERNAL_AUTOTOR: case ADDR_INTERNAL_STATICTOR: break; } if (!host) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't connect to %u address", addr->itype); io_set_finish(conn, destroy_io_conn, connect); return io_tor_connect(conn, connect->daemon->proxyaddr, host, port, connect); } /*~ This is the routine which tries to connect. */ static void try_connect_one_addr(struct connecting *connect) { int fd, af; bool use_proxy = connect->daemon->always_use_proxy; const struct wireaddr_internal *addr = &connect->addrs[connect->addrnum]; struct io_conn *conn; #if EXPERIMENTAL_FEATURES /* BOLT7 DNS RFC #911 */ bool use_dns = connect->daemon->use_dns; struct addrinfo hints, *ais, *aii; struct wireaddr_internal addrhint; int gai_err; struct sockaddr_in *sa4; struct sockaddr_in6 *sa6; #endif assert(!connect->conn); /* Out of addresses? */ if (connect->addrnum == tal_count(connect->addrs)) { connect_failed(connect->daemon, &connect->id, connect->seconds_waited, connect->addrhint, CONNECT_ALL_ADDRESSES_FAILED, "All addresses failed: %s", connect->errors); tal_free(connect); return; } /* Might not even be able to create eg. IPv6 sockets */ af = -1; switch (addr->itype) { case ADDR_INTERNAL_SOCKNAME: af = AF_LOCAL; /* Local sockets don't use tor proxy */ use_proxy = false; break; case ADDR_INTERNAL_ALLPROTO: status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't connect ALLPROTO"); case ADDR_INTERNAL_AUTOTOR: status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't connect AUTOTOR"); case ADDR_INTERNAL_STATICTOR: status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't connect STATICTOR"); case ADDR_INTERNAL_FORPROXY: use_proxy = true; break; case ADDR_INTERNAL_WIREADDR: switch (addr->u.wireaddr.type) { case ADDR_TYPE_TOR_V2_REMOVED: af = -1; break; case ADDR_TYPE_TOR_V3: use_proxy = true; break; case ADDR_TYPE_IPV4: af = AF_INET; break; case ADDR_TYPE_IPV6: af = AF_INET6; break; case ADDR_TYPE_DNS: #if EXPERIMENTAL_FEATURES /* BOLT7 DNS RFC #911 */ if (use_proxy) /* hand it to the proxy */ break; if (!use_dns) { /* ignore DNS when we can't use it */ tal_append_fmt(&connect->errors, "%s: dns disabled. ", type_to_string(tmpctx, struct wireaddr_internal, addr)); goto next; } /* Resolve with getaddrinfo */ memset(&hints, 0, sizeof(hints)); hints.ai_socktype = SOCK_STREAM; hints.ai_family = AF_UNSPEC; hints.ai_protocol = 0; hints.ai_flags = AI_ADDRCONFIG; gai_err = getaddrinfo((char *)addr->u.wireaddr.addr, tal_fmt(tmpctx, "%d", addr->u.wireaddr.port), &hints, &ais); if (gai_err != 0) { tal_append_fmt(&connect->errors, "%s: getaddrinfo error '%s'. ", type_to_string(tmpctx, struct wireaddr_internal, addr), gai_strerror(gai_err)); goto next; } /* create new addrhints on-the-fly per result ... */ for (aii = ais; aii; aii = aii->ai_next) { addrhint.itype = ADDR_INTERNAL_WIREADDR; if (aii->ai_family == AF_INET) { sa4 = (struct sockaddr_in *) aii->ai_addr; wireaddr_from_ipv4(&addrhint.u.wireaddr, &sa4->sin_addr, addr->u.wireaddr.port); } else if (aii->ai_family == AF_INET6) { sa6 = (struct sockaddr_in6 *) aii->ai_addr; wireaddr_from_ipv6(&addrhint.u.wireaddr, &sa6->sin6_addr, addr->u.wireaddr.port); } else { /* skip unsupported ai_family */ continue; } tal_arr_expand(&connect->addrs, addrhint); /* don't forget to update convenience pointer */ addr = &connect->addrs[connect->addrnum]; } freeaddrinfo(ais); #endif tal_append_fmt(&connect->errors, "%s: EXPERIMENTAL_FEATURES needed. ", type_to_string(tmpctx, struct wireaddr_internal, addr)); goto next; case ADDR_TYPE_WEBSOCKET: af = -1; break; } } /* If we have to use proxy but we don't have one, we fail. */ if (use_proxy) { if (!connect->daemon->proxyaddr) { tal_append_fmt(&connect->errors, "%s: need a proxy. ", type_to_string(tmpctx, struct wireaddr_internal, addr)); goto next; } af = connect->daemon->proxyaddr->ai_family; } if (af == -1) { tal_append_fmt(&connect->errors, "%s: not supported. ", type_to_string(tmpctx, struct wireaddr_internal, addr)); goto next; } fd = socket(af, SOCK_STREAM, 0); if (fd < 0) { tal_append_fmt(&connect->errors, "%s: opening %i socket gave %s. ", type_to_string(tmpctx, struct wireaddr_internal, addr), af, strerror(errno)); goto next; } /* This creates the new connection using our fd, with the initialization * function one of the above. */ if (use_proxy) conn = io_new_conn(connect, fd, conn_proxy_init, connect); else conn = io_new_conn(connect, fd, conn_init, connect); /* Careful! io_new_conn can fail (immediate connect() failure), and * that frees connect. */ if (conn) connect->conn = conn; return; next: /* This causes very limited recursion. */ connect->addrnum++; try_connect_one_addr(connect); } /*~ Sometimes it's nice to have an explicit enum instead of a bool to make * arguments clearer: it kind of hacks around C's lack of naming formal * arguments in callers (e.g. in Python we'd simply call func(websocket=False)). */ enum is_websocket { NORMAL_SOCKET, WEBSOCKET, }; /*~ connectd is responsible for incoming connections, but it's the process of * setting up the listening ports which gives us information we need for startup * (such as our own address). So we perform setup in two phases: first we bind * the sockets according to the command line arguments (if any), then we start * listening for connections to them once lightningd is ready. * * This stores the fds we're going to listen on: */ struct listen_fd { /* This is usually an IPv4/v6 address, but we also support local * domain sockets (i.e. filesystem) */ struct wireaddr_internal wi; /* The actual fd, ready to listen() on */ int fd; /* If we bind() IPv6 then IPv4 to same port, we *may* fail to listen() * on the IPv4 socket: under Linux, by default, the IPv6 listen() * covers IPv4 too. Normally we'd consider failing to listen on a * port to be fatal, so we note this when setting up addresses. */ bool mayfail; /* Is this a websocket? */ enum is_websocket is_websocket; }; static struct listen_fd *listen_fd_new(const tal_t *ctx, const struct wireaddr_internal *wi, int fd, bool mayfail, enum is_websocket is_websocket) { struct listen_fd *l = tal(ctx, struct listen_fd); l->wi = *wi; l->fd = fd; l->mayfail = mayfail; l->is_websocket = is_websocket; return l; } /*~ Helper routine to create and bind a socket of a given type; like many * daemons we set it SO_REUSEADDR so we won't have to wait 2 minutes to reuse * it on restart. * * Note that it's generally an antipattern to have a function which * returns an allocated object without an explicit tal ctx so the * caller is aware. */ static struct listen_fd *make_listen_fd(const tal_t *ctx, const struct wireaddr_internal *wi, int domain, void *addr, socklen_t len, bool listen_mayfail, enum is_websocket is_websocket, char **errstr) { int fd = socket(domain, SOCK_STREAM, 0); int on = 1; if (fd < 0) { const char *es = strerror(errno); *errstr = tal_fmt(ctx, "Failed to create socket for %s%s: %s", is_websocket ? "websocket " : "", type_to_string(tmpctx, struct wireaddr_internal, wi), es); status_debug("Failed to create %u socket: %s", domain, es); return NULL; } /* Re-use, please.. */ if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))) status_unusual("Failed setting socket reuse: %s", strerror(errno)); if (bind(fd, addr, len) != 0) { const char *es = strerror(errno); *errstr = tal_fmt(ctx, "Failed to bind socket for %s%s: %s", is_websocket ? "websocket " : "", type_to_string(tmpctx, struct wireaddr_internal, wi), es); status_debug("Failed to bind %u socket: %s", domain, es); goto fail; } *errstr = NULL; status_debug("Created %slistener on %s", is_websocket ? "websocket ": "", type_to_string(tmpctx, struct wireaddr_internal, wi)); return listen_fd_new(ctx, wi, fd, listen_mayfail, is_websocket); fail: /*~ ccan/noerr contains convenient routines which don't clobber the * errno global; in this case, the caller can report errno. */ close_noerr(fd); return NULL; } /* Return true if it created socket successfully. If errstr is non-NULL, * allocate off ctx if return false, otherwise it implies it's OK to fail. */ static struct listen_fd *handle_wireaddr_listen(const tal_t *ctx, const struct wireaddr_internal *wi, bool listen_mayfail, enum is_websocket is_websocket, char **errstr) { struct sockaddr_in addr; struct sockaddr_in6 addr6; const struct wireaddr *wireaddr; assert(wi->itype == ADDR_INTERNAL_WIREADDR); wireaddr = &wi->u.wireaddr; /* Note the use of a switch() over enum here, even though it must be * IPv4 or IPv6 here; that will catch future changes. */ switch (wireaddr->type) { case ADDR_TYPE_IPV4: wireaddr_to_ipv4(wireaddr, &addr); /* We might fail if IPv6 bound to port first */ return make_listen_fd(ctx, wi, AF_INET, &addr, sizeof(addr), listen_mayfail, is_websocket, errstr); case ADDR_TYPE_IPV6: wireaddr_to_ipv6(wireaddr, &addr6); return make_listen_fd(ctx, wi, AF_INET6, &addr6, sizeof(addr6), listen_mayfail, is_websocket, errstr); /* Handle specially by callers. */ case ADDR_TYPE_WEBSOCKET: case ADDR_TYPE_TOR_V2_REMOVED: case ADDR_TYPE_TOR_V3: case ADDR_TYPE_DNS: break; } status_failed(STATUS_FAIL_INTERNAL_ERROR, "Invalid listener wireaddress type %u", wireaddr->type); } /* If it's a wildcard, turns it into a real address pointing to internet */ static bool public_address(struct daemon *daemon, struct wireaddr *wireaddr) { if (wireaddr_is_wildcard(wireaddr)) { if (!guess_address(wireaddr)) return false; } /* --dev-allow-localhost treats the localhost as "public" for testing */ return address_routable(wireaddr, daemon->dev_allow_localhost); } static void add_announceable(struct wireaddr **announceable, const struct wireaddr *addr) { /*~ utils.h contains a convenience macro tal_arr_expand which * reallocates a tal_arr to make it one longer, then returns a pointer * to the (new) last element. */ tal_arr_expand(announceable, *addr); } /* We need to have a bound address we can tell Tor to connect to */ static const struct wireaddr * find_local_address(const struct listen_fd **listen_fds) { for (size_t i = 0; i < tal_count(listen_fds); i++) { if (listen_fds[i]->wi.itype != ADDR_INTERNAL_WIREADDR) continue; if (listen_fds[i]->wi.u.wireaddr.type != ADDR_TYPE_IPV4 && listen_fds[i]->wi.u.wireaddr.type != ADDR_TYPE_IPV6) continue; return &listen_fds[i]->wi.u.wireaddr; } return NULL; } static bool want_tor(const struct wireaddr_internal *proposed_wireaddr) { for (size_t i = 0; i < tal_count(proposed_wireaddr); i++) { if (proposed_wireaddr[i].itype == ADDR_INTERNAL_STATICTOR || proposed_wireaddr[i].itype == ADDR_INTERNAL_AUTOTOR) return true; } return false; } /*~ The user can specify three kinds of addresses: ones we bind to but don't * announce, ones we announce but don't bind to, and ones we bind to and * announce if they seem to be public addresses. * * This routine sorts out the mess: it populates the *announceable array, * and returns the addresses we bound to (by convention, return is allocated * off `ctx` argument). * * Note the important difference between returning a zero-element array, and * returning NULL! The latter means failure here, the former simply means * we don't want to listen to anything. */ static const struct listen_fd ** setup_listeners(const tal_t *ctx, struct daemon *daemon, /* The proposed address. */ const struct wireaddr_internal *proposed_wireaddr, /* For each one, listen, announce or both */ const enum addr_listen_announce *proposed_listen_announce, const char *tor_password, struct wireaddr **announceable, char **errstr) { struct sockaddr_un addrun; const struct listen_fd **listen_fds, *lfd; const char *blob = NULL; struct secret random; struct pubkey pb; struct wireaddr *toraddr; const struct wireaddr *localaddr; /* Start with empty arrays, for tal_arr_expand() */ listen_fds = tal_arr(ctx, const struct listen_fd *, 0); *announceable = tal_arr(ctx, struct wireaddr, 0); /* Add addresses we've explicitly been told to *first*: implicit * addresses will be discarded then if we have multiple. */ for (size_t i = 0; i < tal_count(proposed_wireaddr); i++) { struct wireaddr_internal wa = proposed_wireaddr[i]; /* We want announce-only addresses. */ if (proposed_listen_announce[i] & ADDR_LISTEN) continue; assert(proposed_listen_announce[i] & ADDR_ANNOUNCE); /* You can only announce wiretypes, not internal formats! */ assert(proposed_wireaddr[i].itype == ADDR_INTERNAL_WIREADDR); add_announceable(announceable, &wa.u.wireaddr); } /* Now look for listening addresses. */ for (size_t i = 0; i < tal_count(proposed_wireaddr); i++) { struct wireaddr_internal wa = proposed_wireaddr[i]; bool announce = (proposed_listen_announce[i] & ADDR_ANNOUNCE); if (!(proposed_listen_announce[i] & ADDR_LISTEN)) continue; switch (wa.itype) { /* We support UNIX domain sockets, but can't announce */ case ADDR_INTERNAL_SOCKNAME: addrun.sun_family = AF_UNIX; memcpy(addrun.sun_path, wa.u.sockname, sizeof(addrun.sun_path)); /* Remove any existing one. */ unlink(wa.u.sockname); lfd = make_listen_fd(ctx, &wa, AF_UNIX, &addrun, sizeof(addrun), false, NORMAL_SOCKET, errstr); /* Don't bother freeing here; we'll exit */ if (!lfd) return NULL; /* We don't announce socket names, though we allow * them to lazily specify --addr=/socket. */ tal_arr_expand(&listen_fds, tal_steal(listen_fds, lfd)); continue; case ADDR_INTERNAL_AUTOTOR: /* We handle these after we have all bindings. */ continue; case ADDR_INTERNAL_STATICTOR: /* We handle these after we have all bindings. */ continue; /* Special case meaning IPv6 and IPv4 */ case ADDR_INTERNAL_ALLPROTO: { bool ipv6_ok; wa.itype = ADDR_INTERNAL_WIREADDR; wa.u.wireaddr.port = wa.u.port; /* First, create wildcard IPv6 address. */ wa.u.wireaddr.type = ADDR_TYPE_IPV6; wa.u.wireaddr.addrlen = 16; memset(wa.u.wireaddr.addr, 0, sizeof(wa.u.wireaddr.addr)); /* This may fail due to no IPv6 support. */ lfd = handle_wireaddr_listen(ctx, &wa, false, NORMAL_SOCKET, errstr); if (lfd) { tal_arr_expand(&listen_fds, tal_steal(listen_fds, lfd)); if (announce && public_address(daemon, &wa.u.wireaddr)) add_announceable(announceable, &wa.u.wireaddr); } ipv6_ok = (lfd != NULL); /* Now, create wildcard IPv4 address. */ wa.u.wireaddr.type = ADDR_TYPE_IPV4; wa.u.wireaddr.addrlen = 4; memset(wa.u.wireaddr.addr, 0, sizeof(wa.u.wireaddr.addr)); /* This listen *may* fail, as long as IPv6 succeeds! */ lfd = handle_wireaddr_listen(ctx, &wa, ipv6_ok, NORMAL_SOCKET, errstr); if (lfd) { tal_arr_expand(&listen_fds, tal_steal(listen_fds, lfd)); if (announce && public_address(daemon, &wa.u.wireaddr)) add_announceable(announceable, &wa.u.wireaddr); } else if (!ipv6_ok) { /* Both failed, return now, errstr set. */ return NULL; } continue; } /* This is a vanilla wireaddr as per BOLT #7 */ case ADDR_INTERNAL_WIREADDR: lfd = handle_wireaddr_listen(ctx, &wa, false, NORMAL_SOCKET, errstr); if (!lfd) return NULL; tal_arr_expand(&listen_fds, tal_steal(listen_fds, lfd)); if (announce && public_address(daemon, &wa.u.wireaddr)) add_announceable(announceable, &wa.u.wireaddr); continue; case ADDR_INTERNAL_FORPROXY: break; } /* Shouldn't happen. */ status_failed(STATUS_FAIL_INTERNAL_ERROR, "Invalid listener address type %u", proposed_wireaddr[i].itype); } /* Make sure we have at least one non-websocket address to send to, * for Tor */ localaddr = find_local_address(listen_fds); if (want_tor(proposed_wireaddr) && !localaddr) { *errstr = "Need to bind at least one local address," " to send Tor connections to"; return NULL; } /* If we want websockets to match IPv4/v6, set it up now. */ if (daemon->websocket_port) { bool announced_some = false; struct wireaddr_internal addr; /* Only consider bindings added before this! */ size_t num_nonws_listens = tal_count(listen_fds); /* If not overriden below, this is the default. */ *errstr = "Cannot listen on websocket: not listening on any IPv4/6 addresses"; for (size_t i = 0; i < num_nonws_listens; i++) { /* Ignore UNIX sockets */ if (listen_fds[i]->wi.itype != ADDR_INTERNAL_WIREADDR) continue; /* Override with websocket port */ addr = listen_fds[i]->wi; addr.u.wireaddr.port = daemon->websocket_port; /* We set mayfail on all but the first websocket; * it's quite common to have multple overlapping * addresses. */ lfd = handle_wireaddr_listen(ctx, &addr, announced_some, WEBSOCKET, errstr); if (!lfd) continue; if (!announced_some) { /* BOLT-websocket #7: * - MUST NOT add a `type 6` address unless * there is also at least one address of * different type. */ if (tal_count(*announceable) != 0) { /* See https://github.com/lightningnetwork/lnd/issues/6432: * if we add websocket to the node_announcement, it doesn't propagate. * So we do not do this for now in general! */ if (daemon->announce_websocket) { wireaddr_from_websocket(&addr.u.wireaddr, daemon->websocket_port); add_announceable(announceable, &addr.u.wireaddr); } } else { status_unusual("Bound to websocket %s," " but we cannot announce" " the websocket as we don't" " announce anything else!", type_to_string(tmpctx, struct wireaddr_internal, &addr)); } announced_some = true; } tal_arr_expand(&listen_fds, tal_steal(listen_fds, lfd)); } /* If none of those was possible, it's a configuration error? */ if (tal_count(listen_fds) == num_nonws_listens) return NULL; } /* FIXME: Websocket over Tor (difficult for autotor, since we need * to use the same onion addr!) */ /* Now we have bindings, set up any Tor auto addresses: we will point * it at the first bound IPv4 or IPv6 address we have. */ for (size_t i = 0; i < tal_count(proposed_wireaddr); i++) { if (!(proposed_listen_announce[i] & ADDR_LISTEN)) continue; if (proposed_wireaddr[i].itype != ADDR_INTERNAL_AUTOTOR) continue; toraddr = tor_autoservice(tmpctx, &proposed_wireaddr[i], tor_password, localaddr); if (!(proposed_listen_announce[i] & ADDR_ANNOUNCE)) { continue; }; add_announceable(announceable, toraddr); } /* Now we have bindings, set up any Tor static addresses: we will point * it at the first bound IPv4 or IPv6 address we have. */ for (size_t i = 0; i < tal_count(proposed_wireaddr); i++) { if (!(proposed_listen_announce[i] & ADDR_LISTEN)) continue; if (proposed_wireaddr[i].itype != ADDR_INTERNAL_STATICTOR) continue; blob = proposed_wireaddr[i].u.torservice.blob; if (tal_strreg(tmpctx, (char *)proposed_wireaddr[i].u.torservice.blob, STATIC_TOR_MAGIC_STRING)) { if (pubkey_from_node_id(&pb, &daemon->id)) { if (sodium_mlock(&random, sizeof(random)) != 0) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not lock the random prf key memory."); randombytes_buf((void * const)&random, 32); /* generate static tor node address, take first 32 bytes from secret of node_id plus 32 random bytes from sodiom */ struct sha256 sha; struct secret ss; ecdh(&pb, &ss); /* let's sha, that will clear ctx of hsm data */ sha256(&sha, &ss, 32); /* even if it's a secret pub derived, tor shall see only the single sha */ memcpy((void *)&blob[0], &sha, 32); memcpy((void *)&blob[32], &random, 32); /* clear our temp buffer, don't leak by extern libs core-dumps, our blob we/tal handle later */ sodium_munlock(&random, sizeof(random)); } else status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not get the pub of our node id from hsm"); } toraddr = tor_fixed_service(tmpctx, &proposed_wireaddr[i], tor_password, blob, localaddr, 0); /* get rid of blob data on our side of tor and add jitter */ randombytes_buf((void * const)proposed_wireaddr[i].u.torservice.blob, TOR_V3_BLOBLEN); if (!(proposed_listen_announce[i] & ADDR_ANNOUNCE)) { continue; }; add_announceable(announceable, toraddr); } /*~ The spec used to ban more than one address of each type, but * nobody could remember exactly why, so now that's allowed. */ /* BOLT #7: * * The origin node: *... * - MUST place address descriptors in ascending order. */ asort(*announceable, tal_count(*announceable), wireaddr_cmp_type, NULL); *errstr = NULL; return listen_fds; } /*~ Parse the incoming connect init message from lightningd ("master") and * assign config variables to the daemon; it should be the first message we * get. */ static void connect_init(struct daemon *daemon, const u8 *msg) { struct wireaddr *proxyaddr; struct wireaddr_internal *binding; struct wireaddr_internal *proposed_wireaddr; enum addr_listen_announce *proposed_listen_announce; struct wireaddr *announceable; char *tor_password; bool dev_fast_gossip; bool dev_disconnect, dev_no_ping_timer; char *errstr; /* Fields which require allocation are allocated off daemon */ if (!fromwire_connectd_init( daemon, msg, &chainparams, &daemon->our_features, &daemon->id, &proposed_wireaddr, &proposed_listen_announce, &proxyaddr, &daemon->always_use_proxy, &daemon->dev_allow_localhost, &daemon->use_dns, &tor_password, &daemon->timeout_secs, &daemon->websocket_helper, &daemon->websocket_port, &daemon->announce_websocket, &dev_fast_gossip, &dev_disconnect, &dev_no_ping_timer)) { /* This is a helper which prints the type expected and the actual * message, then exits (it should never be called!). */ master_badmsg(WIRE_CONNECTD_INIT, msg); } #if DEVELOPER /*~ Clearly mark these as developer-only flags! */ daemon->dev_fast_gossip = dev_fast_gossip; daemon->dev_no_ping_timer = dev_no_ping_timer; daemon->dev_suppress_gossip = false; #endif if (!pubkey_from_node_id(&daemon->mykey, &daemon->id)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Invalid id for me %s", type_to_string(tmpctx, struct node_id, &daemon->id)); /* Resolve Tor proxy address if any: we need an addrinfo to connect() * to. */ if (proxyaddr) { status_debug("Proxy address: %s", fmt_wireaddr(tmpctx, proxyaddr)); daemon->proxyaddr = wireaddr_to_addrinfo(daemon, proxyaddr); tal_free(proxyaddr); } else daemon->proxyaddr = NULL; if (broken_resolver(daemon)) { status_debug("Broken DNS resolver detected, will check for " "dummy replies"); } /* Figure out our addresses. */ daemon->listen_fds = setup_listeners(daemon, daemon, proposed_wireaddr, proposed_listen_announce, tor_password, &announceable, &errstr); /* Free up old allocations */ tal_free(proposed_wireaddr); tal_free(proposed_listen_announce); tal_free(tor_password); /* Create binding array to send to lightningd */ binding = tal_arr(tmpctx, struct wireaddr_internal, 0); for (size_t i = 0; i < tal_count(daemon->listen_fds); i++) { /* FIXME: Tell it about websockets! */ if (daemon->listen_fds[i]->is_websocket) continue; tal_arr_expand(&binding, daemon->listen_fds[i]->wi); } /* Tell it we're ready, handing it the addresses we have. */ daemon_conn_send(daemon->master, take(towire_connectd_init_reply(NULL, binding, announceable, errstr))); /*~ Who cares about a little once-off memory leak? Turns out we do! * We have a memory leak checker which scans for allocated memory * with no pointers to it (a tell-tale leak sign, though with tal it's * not always a real problem), and this would (did!) trigger it. */ tal_free(announceable); #if DEVELOPER if (dev_disconnect) dev_disconnect_init(5); #endif } /* Returning functions in C is ugly! */ static struct io_plan *(*get_in_cb(enum is_websocket is_websocket))(struct io_conn *, struct daemon *) { /*~ This switch and fall pattern serves a specific purpose: * gcc will warn if we don't handle every case! */ switch (is_websocket) { case WEBSOCKET: return websocket_connection_in; case NORMAL_SOCKET: return connection_in; } status_failed(STATUS_FAIL_INTERNAL_ERROR, "Invalid is_websocket %u", is_websocket); } /*~ lightningd tells us to go! */ static void connect_activate(struct daemon *daemon, const u8 *msg) { bool do_listen; char *errmsg = NULL; if (!fromwire_connectd_activate(msg, &do_listen)) master_badmsg(WIRE_CONNECTD_ACTIVATE, msg); /* If we're --offline, lightningd tells us not to actually listen. */ if (do_listen) { for (size_t i = 0; i < tal_count(daemon->listen_fds); i++) { if (listen(daemon->listen_fds[i]->fd, 64) != 0) { if (daemon->listen_fds[i]->mayfail) continue; errmsg = tal_fmt(tmpctx, "Failed to listen on socket %s: %s", type_to_string(tmpctx, struct wireaddr_internal, &daemon->listen_fds[i]->wi), strerror(errno)); break; } notleak(io_new_listener(daemon, daemon->listen_fds[i]->fd, get_in_cb(daemon->listen_fds[i] ->is_websocket), daemon)); } } /* Free, with NULL assignment just as an extra sanity check. */ daemon->listen_fds = tal_free(daemon->listen_fds); /* OK, we're ready! */ daemon_conn_send(daemon->master, take(towire_connectd_activate_reply(NULL, errmsg))); } /* BOLT #10: * * The DNS seed: * ... * - upon receiving a _node_ query: * - MUST select the record matching the `node_id`, if any, AND return all * addresses associated with that node. */ static const char **seednames(const tal_t *ctx, const struct node_id *id) { char bech32[100]; u5 *data = tal_arr(ctx, u5, 0); const char **seednames = tal_arr(ctx, const char *, 0); bech32_push_bits(&data, id->k, ARRAY_SIZE(id->k)*8); bech32_encode(bech32, "ln", data, tal_count(data), sizeof(bech32), BECH32_ENCODING_BECH32); /* This is cdecker's seed */ tal_arr_expand(&seednames, tal_fmt(seednames, "%s.lseed.bitcoinstats.com", bech32)); /* This is darosior's seed */ tal_arr_expand(&seednames, tal_fmt(seednames, "%s.lseed.darosior.ninja", bech32)); return seednames; } /*~ As a last resort, we do a DNS lookup to the lightning DNS seed to * resolve a node name when they say to connect to it. This is synchronous, * so connectd blocks, but it's not very common so we haven't fixed it. * * This "seed by DNS" approach is similar to what bitcoind uses, and in fact * has the nice property that DNS is cached, and the seed only sees a request * from the ISP, not directly from the user. */ static void add_seed_addrs(struct wireaddr_internal **addrs, const struct node_id *id, struct sockaddr *broken_reply) { struct wireaddr *new_addrs; const char **hostnames = seednames(tmpctx, id); for (size_t i = 0; i < tal_count(hostnames); i++) { status_peer_debug(id, "Resolving %s", hostnames[i]); new_addrs = wireaddr_from_hostname(tmpctx, hostnames[i], chainparams_get_ln_port(chainparams), NULL, broken_reply, NULL); if (new_addrs) { for (size_t j = 0; j < tal_count(new_addrs); j++) { #if EXPERIMENTAL_FEATURES /* BOLT7 DNS RFC #911 */ if (new_addrs[j].type == ADDR_TYPE_DNS) continue; #endif struct wireaddr_internal a; a.itype = ADDR_INTERNAL_WIREADDR; a.u.wireaddr = new_addrs[j]; status_peer_debug(id, "Resolved %s to %s", hostnames[i], type_to_string(tmpctx, struct wireaddr, &a.u.wireaddr)); tal_arr_expand(addrs, a); } /* Other seeds will likely have the same information. */ return; } else status_peer_debug(id, "Could not resolve %s", hostnames[i]); } } static bool wireaddr_int_equals_wireaddr(const struct wireaddr_internal *addr_a, const struct wireaddr *addr_b) { if (!addr_a || !addr_b) return false; return wireaddr_eq(&addr_a->u.wireaddr, addr_b); } /*~ Adds just one address type. * * Ignores deprecated and the `addrhint`. */ static void add_gossip_addrs_bytype(struct wireaddr_internal **addrs, const struct wireaddr *normal_addrs, const struct wireaddr_internal *addrhint, const enum wire_addr_type type) { for (size_t i = 0; i < tal_count(normal_addrs); i++) { if (normal_addrs[i].type == ADDR_TYPE_TOR_V2_REMOVED) continue; if (wireaddr_int_equals_wireaddr(addrhint, &normal_addrs[i])) continue; if (normal_addrs[i].type != type) continue; struct wireaddr_internal addr; addr.itype = ADDR_INTERNAL_WIREADDR; addr.u.wireaddr = normal_addrs[i]; tal_arr_expand(addrs, addr); } } /*~ Orders the addresses which lightningd gave us. * * Ignores deprecated protocols and the `addrhint` that is assumed to be * already added first. Adds all IPv6 addresses, followed by IPv4 and then TOR. * This ensures we are modern and use IPv6 when possible, falling back to * direct (faster) IPv4 and finally (less stable) TOR connections. */ static void add_gossip_addrs(struct wireaddr_internal **addrs, const struct wireaddr *normal_addrs, const struct wireaddr_internal *addrhint) { /* Wrap each one in a wireaddr_internal and add to addrs. */ for (size_t i = 0; i < tal_count(normal_addrs); i++) { /* This is not supported, ignore. */ if (normal_addrs[i].type == ADDR_TYPE_TOR_V2_REMOVED) continue; /* The hint was already added earlier */ if (wireaddr_int_equals_wireaddr(addrhint, &normal_addrs[i])) continue; /* We add IPv4 and TOR in separate loops to prefer IPv6 */ if (normal_addrs[i].type == ADDR_TYPE_IPV4) continue; if (normal_addrs[i].type == ADDR_TYPE_TOR_V3) continue; struct wireaddr_internal addr; addr.itype = ADDR_INTERNAL_WIREADDR; addr.u.wireaddr = normal_addrs[i]; tal_arr_expand(addrs, addr); } /* Do the loop for skipped protocols in preferred order. */ add_gossip_addrs_bytype(addrs, normal_addrs, addrhint, ADDR_TYPE_IPV4); add_gossip_addrs_bytype(addrs, normal_addrs, addrhint, ADDR_TYPE_TOR_V3); } /*~ Consumes addrhint if not NULL. * * That's a pretty ugly interface: we should use TAKEN, but we only have one * caller so it's marginal. */ static void try_connect_peer(struct daemon *daemon, const struct node_id *id, u32 seconds_waited, struct wireaddr *gossip_addrs, struct wireaddr_internal *addrhint STEALS) { struct wireaddr_internal *addrs; bool use_proxy = daemon->always_use_proxy; struct connecting *connect; /* Already existing? Must have crossed over, it'll know soon. */ if (peer_htable_get(&daemon->peers, id)) return; /* If we're trying to connect it right now, that's OK. */ if ((connect = find_connecting(daemon, id))) { /* If we've been passed in new connection details * for this connection, update our addrhint + add * to addresses to check */ if (addrhint) { connect->addrhint = tal_steal(connect, addrhint); tal_arr_expand(&connect->addrs, *addrhint); } return; } /* Start an array of addresses to try. */ addrs = tal_arr(tmpctx, struct wireaddr_internal, 0); /* They can supply an optional address for the connect RPC */ /* We add this first so its tried first by connectd */ if (addrhint) tal_arr_expand(&addrs, *addrhint); add_gossip_addrs(&addrs, gossip_addrs, addrhint); if (tal_count(addrs) == 0) { /* Don't resolve via DNS seed if we're supposed to use proxy. */ if (use_proxy) { /* You're allowed to use names with proxies; in fact it's * a good idea. */ struct wireaddr_internal unresolved; const char **hostnames = seednames(tmpctx, id); for (size_t i = 0; i < tal_count(hostnames); i++) { wireaddr_from_unresolved(&unresolved, hostnames[i], chainparams_get_ln_port(chainparams)); tal_arr_expand(&addrs, unresolved); } } else if (daemon->use_dns) { add_seed_addrs(&addrs, id, daemon->broken_resolver_response); } } /* Still no address? Fail immediately. Lightningd can still choose * to retry; an address may get gossiped or appear on the DNS seed. */ if (tal_count(addrs) == 0) { connect_failed(daemon, id, seconds_waited, addrhint, CONNECT_NO_KNOWN_ADDRESS, "Unable to connect, no address known for peer"); return; } /* Start connecting to it: since this is the only place we allocate * a 'struct connecting' we don't write a separate new_connecting(). */ connect = tal(daemon, struct connecting); connect->daemon = daemon; connect->id = *id; connect->addrs = tal_steal(connect, addrs); connect->addrnum = 0; /* connstate is supposed to be updated as we go, to give context for * errors which occur. We miss it in a few places; would be nice to * fix! */ connect->connstate = "Connection establishment"; connect->seconds_waited = seconds_waited; connect->addrhint = tal_steal(connect, addrhint); connect->errors = tal_strdup(connect, ""); connect->conn = NULL; list_add_tail(&daemon->connecting, &connect->list); tal_add_destructor(connect, destroy_connecting); /* Now we kick it off by recursively trying connect->addrs[connect->addrnum] */ try_connect_one_addr(connect); } /* lightningd tells us to connect to a peer by id, with optional addr hint. */ static void connect_to_peer(struct daemon *daemon, const u8 *msg) { struct node_id id; u32 seconds_waited; struct wireaddr_internal *addrhint; struct wireaddr *addrs; if (!fromwire_connectd_connect_to_peer(tmpctx, msg, &id, &seconds_waited, &addrs, &addrhint)) master_badmsg(WIRE_CONNECTD_CONNECT_TO_PEER, msg); try_connect_peer(daemon, &id, seconds_waited, addrs, addrhint); } /* lightningd tells us a peer should be disconnected. */ static void peer_discard(struct daemon *daemon, const u8 *msg) { struct node_id id; u64 counter; struct peer *peer; if (!fromwire_connectd_discard_peer(msg, &id, &counter)) master_badmsg(WIRE_CONNECTD_DISCARD_PEER, msg); /* We should stay in sync with lightningd, but this can happen * under stress. */ peer = peer_htable_get(&daemon->peers, &id); if (!peer) return; /* If it's reconnected already, it will learn soon. */ if (peer->counter != counter) return; status_peer_debug(&id, "discard_peer"); tal_free(peer); } /* lightningd tells us to send a msg and disconnect. */ static void peer_final_msg(struct io_conn *conn, struct daemon *daemon, const u8 *msg) { struct peer *peer; struct node_id id; u64 counter; u8 *finalmsg; if (!fromwire_connectd_peer_final_msg(tmpctx, msg, &id, &counter, &finalmsg)) master_badmsg(WIRE_CONNECTD_PEER_FINAL_MSG, msg); /* This can happen if peer hung up on us (or wrong counter * if it reconnected). */ peer = peer_htable_get(&daemon->peers, &id); if (peer && peer->counter == counter) { /* Log message for peer. */ status_peer_io(LOG_IO_OUT, &id, finalmsg); multiplex_final_msg(peer, take(finalmsg)); } } #if DEVELOPER static void dev_connect_memleak(struct daemon *daemon, const u8 *msg) { struct htable *memtable; bool found_leak; memtable = memleak_find_allocations(tmpctx, msg, msg); /* Now delete daemon and those which it has pointers to. */ memleak_remove_region(memtable, daemon, sizeof(daemon)); memleak_remove_htable(memtable, &daemon->peers.raw); found_leak = dump_memleak(memtable, memleak_status_broken); daemon_conn_send(daemon->master, take(towire_connectd_dev_memleak_reply(NULL, found_leak))); } static void dev_suppress_gossip(struct daemon *daemon, const u8 *msg) { daemon->dev_suppress_gossip = true; } #endif /* DEVELOPER */ static struct io_plan *recv_peer_connect_subd(struct io_conn *conn, const u8 *msg, int fd, struct daemon *daemon) { peer_connect_subd(daemon, msg, fd); return daemon_conn_read_next(conn, daemon->master); } static struct io_plan *recv_req(struct io_conn *conn, const u8 *msg, struct daemon *daemon) { enum connectd_wire t = fromwire_peektype(msg); /* Demux requests from lightningd: we expect INIT then ACTIVATE, then * connect requests and disconnected messages. */ switch (t) { case WIRE_CONNECTD_INIT: connect_init(daemon, msg); goto out; case WIRE_CONNECTD_ACTIVATE: connect_activate(daemon, msg); goto out; case WIRE_CONNECTD_CONNECT_TO_PEER: connect_to_peer(daemon, msg); goto out; case WIRE_CONNECTD_DISCARD_PEER: peer_discard(daemon, msg); goto out; case WIRE_CONNECTD_PEER_FINAL_MSG: peer_final_msg(conn, daemon, msg); goto out; case WIRE_CONNECTD_PING: send_manual_ping(daemon, msg); goto out; case WIRE_CONNECTD_SEND_ONIONMSG: onionmsg_req(daemon, msg); goto out; case WIRE_CONNECTD_CUSTOMMSG_OUT: send_custommsg(daemon, msg); goto out; case WIRE_CONNECTD_PEER_CONNECT_SUBD: /* This comes with an fd */ return daemon_conn_read_with_fd(conn, daemon->master, recv_peer_connect_subd, daemon); case WIRE_CONNECTD_DEV_MEMLEAK: #if DEVELOPER dev_connect_memleak(daemon, msg); goto out; #endif case WIRE_CONNECTD_DEV_SUPPRESS_GOSSIP: #if DEVELOPER dev_suppress_gossip(daemon, msg); goto out; #endif /* We send these, we don't receive them */ case WIRE_CONNECTD_INIT_REPLY: case WIRE_CONNECTD_ACTIVATE_REPLY: case WIRE_CONNECTD_PEER_CONNECTED: case WIRE_CONNECTD_PEER_SPOKE: case WIRE_CONNECTD_CONNECT_FAILED: case WIRE_CONNECTD_DEV_MEMLEAK_REPLY: case WIRE_CONNECTD_PING_REPLY: case WIRE_CONNECTD_GOT_ONIONMSG_TO_US: case WIRE_CONNECTD_CUSTOMMSG_IN: case WIRE_CONNECTD_PEER_DISCONNECT_DONE: break; } /* Master shouldn't give bad requests. */ status_failed(STATUS_FAIL_MASTER_IO, "%i: %s", t, tal_hex(tmpctx, msg)); out: /* Read the next message. */ return daemon_conn_read_next(conn, daemon->master); } /*~ UNUSED is defined to an __attribute__ for GCC; at one stage we tried to use * it ubiquitously to make us compile cleanly with -Wunused, but it's bitrotted * and we'd need to start again. * * The C++ method of omitting unused parameter names is *much* neater, and I * hope we'll eventually see it in a C standard. */ static void master_gone(struct daemon_conn *master UNUSED) { /* Can't tell master, it's gone. */ exit(2); } /*~ gossipd sends us gossip to send to the peers. */ static struct io_plan *recv_gossip(struct io_conn *conn, const u8 *msg, struct daemon *daemon) { struct node_id dst; u8 *gossip_msg; struct peer *peer; if (!fromwire_gossipd_send_gossip(msg, msg, &dst, &gossip_msg)) status_failed(STATUS_FAIL_GOSSIP_IO, "Unknown msg %i", fromwire_peektype(msg)); peer = peer_htable_get(&daemon->peers, &dst); if (peer) inject_peer_msg(peer, take(gossip_msg)); return daemon_conn_read_next(conn, daemon->gossipd); } /*~ This is a hook used by the memleak code (if DEVELOPER=1): it can't see * pointers inside hash tables, so we give it a hint here. */ #if DEVELOPER static void memleak_daemon_cb(struct htable *memtable, struct daemon *daemon) { memleak_remove_htable(memtable, &daemon->peers.raw); } #endif /* DEVELOPER */ int main(int argc, char *argv[]) { setup_locale(); struct daemon *daemon; /* Common subdaemon setup code. */ subdaemon_setup(argc, argv); /* Allocate and set up our simple top-level structure. */ daemon = tal(NULL, struct daemon); daemon->connection_counter = 1; peer_htable_init(&daemon->peers); memleak_add_helper(daemon, memleak_daemon_cb); list_head_init(&daemon->connecting); timers_init(&daemon->timers, time_mono()); daemon->gossip_store_fd = -1; /* stdin == control */ daemon->master = daemon_conn_new(daemon, STDIN_FILENO, recv_req, NULL, daemon); tal_add_destructor(daemon->master, master_gone); /* This tells the status_* subsystem to use this connection to send * our status_ and failed messages. */ status_setup_async(daemon->master); /* Don't leave around websocketd zombies. Technically not portable, * but OK for Linux and BSD, so... */ signal(SIGCHLD, SIG_IGN); /* This streams gossip to and from gossipd */ daemon->gossipd = daemon_conn_new(daemon, GOSSIPCTL_FD, recv_gossip, NULL, daemon); /* Set up ecdh() function so it uses our HSM fd, and calls * status_failed on error. */ ecdh_hsmd_setup(HSM_FD, status_failed); for (;;) { struct timer *expired; io_loop(&daemon->timers, &expired); timer_expired(expired); } } /*~ Getting bored? This was a pretty simple daemon! * * The good news is that the next daemon gossipd/gossipd.c is the most complex * global daemon we have! */