/* * server.c -- nsd(8) network input/output * * Copyright (c) 2001-2011, NLnet Labs. All rights reserved. * * See LICENSE for the license. * */ #include "config.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef SHUT_WR #define SHUT_WR 1 #endif #include #include "axfr.h" #include "namedb.h" #include "netio.h" #include "xfrd.h" #include "xfrd-tcp.h" #include "difffile.h" #include "nsec3.h" #include "ipc.h" #include "lookup3.h" #include "rrl.h" /* * Data for the UDP handlers. */ struct udp_handler_data { struct nsd *nsd; struct nsd_socket *socket; query_type *query; }; /* * Data for the TCP accept handlers. Most data is simply passed along * to the TCP connection handler. */ struct tcp_accept_handler_data { struct nsd *nsd; struct nsd_socket *socket; size_t tcp_accept_handler_count; netio_handler_type *tcp_accept_handlers; }; int slowaccept; struct timespec slowaccept_timeout; /* * Data for the TCP connection handlers. * * The TCP handlers use non-blocking I/O. This is necessary to avoid * blocking the entire server on a slow TCP connection, but does make * reading from and writing to the socket more complicated. * * Basically, whenever a read/write would block (indicated by the * EAGAIN errno variable) we remember the position we were reading * from/writing to and return from the TCP reading/writing event * handler. When the socket becomes readable/writable again we * continue from the same position. */ struct tcp_handler_data { /* * The region used to allocate all TCP connection related * data, including this structure. This region is destroyed * when the connection is closed. */ region_type* region; /* * The global nsd structure. */ struct nsd* nsd; /* * The current query data for this TCP connection. */ query_type* query; /* * These fields are used to enable the TCP accept handlers * when the number of TCP connection drops below the maximum * number of TCP connections. */ size_t tcp_accept_handler_count; netio_handler_type *tcp_accept_handlers; /* * The query_state is used to remember if we are performing an * AXFR, if we're done processing, or if we should discard the * query and connection. */ query_state_type query_state; /* * The bytes_transmitted field is used to remember the number * of bytes transmitted when receiving or sending a DNS * packet. The count includes the two additional bytes used * to specify the packet length on a TCP connection. */ size_t bytes_transmitted; /* * The number of queries handled by this specific TCP connection. */ int query_count; }; /* * Handle incoming queries on the UDP server sockets. */ static void handle_udp(netio_type *netio, netio_handler_type *handler, netio_event_types_type event_types); /* * Handle incoming connections on the TCP sockets. These handlers * usually wait for the NETIO_EVENT_READ event (indicating an incoming * connection) but are disabled when the number of current TCP * connections is equal to the maximum number of TCP connections. * Disabling is done by changing the handler to wait for the * NETIO_EVENT_NONE type. This is done using the function * configure_tcp_accept_handlers. */ static void handle_tcp_accept(netio_type *netio, netio_handler_type *handler, netio_event_types_type event_types); /* * Handle incoming queries on a TCP connection. The TCP connections * are configured to be non-blocking and the handler may be called * multiple times before a complete query is received. */ static void handle_tcp_reading(netio_type *netio, netio_handler_type *handler, netio_event_types_type event_types); /* * Handle outgoing responses on a TCP connection. The TCP connections * are configured to be non-blocking and the handler may be called * multiple times before a complete response is sent. */ static void handle_tcp_writing(netio_type *netio, netio_handler_type *handler, netio_event_types_type event_types); /* * Send all children the quit nonblocking, then close pipe. */ static void send_children_quit(struct nsd* nsd); /* set childrens flags to send NSD_STATS to them */ #ifdef BIND8_STATS static void set_children_stats(struct nsd* nsd); #endif /* BIND8_STATS */ /* * Change the event types the HANDLERS are interested in to * EVENT_TYPES. */ static void configure_handler_event_types(size_t count, netio_handler_type *handlers, netio_event_types_type event_types); /* * start xfrdaemon (again). */ static pid_t server_start_xfrd(struct nsd *nsd, netio_handler_type* handler); static uint16_t *compressed_dname_offsets = 0; static uint32_t compression_table_capacity = 0; static uint32_t compression_table_size = 0; /* * Remove the specified pid from the list of child pids. Returns -1 if * the pid is not in the list, child_num otherwise. The field is set to 0. */ static int delete_child_pid(struct nsd *nsd, pid_t pid) { size_t i; for (i = 0; i < nsd->child_count; ++i) { if (nsd->children[i].pid == pid) { nsd->children[i].pid = 0; if(!nsd->children[i].need_to_exit) { if(nsd->children[i].child_fd != -1) close(nsd->children[i].child_fd); nsd->children[i].child_fd = -1; if(nsd->children[i].handler) nsd->children[i].handler->fd = -1; } return i; } } return -1; } /* * Restart child servers if necessary. */ static int restart_child_servers(struct nsd *nsd, region_type* region, netio_type* netio, int* xfrd_sock_p) { struct main_ipc_handler_data *ipc_data; size_t i; int sv[2]; /* Fork the child processes... */ for (i = 0; i < nsd->child_count; ++i) { if (nsd->children[i].pid <= 0) { if (nsd->children[i].child_fd != -1) close(nsd->children[i].child_fd); if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == -1) { log_msg(LOG_ERR, "socketpair: %s", strerror(errno)); return -1; } nsd->children[i].child_fd = sv[0]; nsd->children[i].parent_fd = sv[1]; nsd->children[i].pid = fork(); switch (nsd->children[i].pid) { default: /* SERVER MAIN */ close(nsd->children[i].parent_fd); nsd->children[i].parent_fd = -1; if(!nsd->children[i].handler) { ipc_data = (struct main_ipc_handler_data*) region_alloc( region, sizeof(struct main_ipc_handler_data)); ipc_data->nsd = nsd; ipc_data->child = &nsd->children[i]; ipc_data->child_num = i; ipc_data->xfrd_sock = xfrd_sock_p; ipc_data->packet = buffer_create(region, QIOBUFSZ); ipc_data->forward_mode = 0; ipc_data->got_bytes = 0; ipc_data->total_bytes = 0; ipc_data->acl_num = 0; ipc_data->busy_writing_zone_state = 0; ipc_data->write_conn = xfrd_tcp_create(region); nsd->children[i].handler = (struct netio_handler*) region_alloc( region, sizeof(struct netio_handler)); nsd->children[i].handler->fd = nsd->children[i].child_fd; nsd->children[i].handler->timeout = NULL; nsd->children[i].handler->user_data = ipc_data; nsd->children[i].handler->event_types = NETIO_EVENT_READ; nsd->children[i].handler->event_handler = parent_handle_child_command; netio_add_handler(netio, nsd->children[i].handler); } /* clear any ongoing ipc */ ipc_data = (struct main_ipc_handler_data*) nsd->children[i].handler->user_data; ipc_data->forward_mode = 0; ipc_data->busy_writing_zone_state = 0; /* restart - update fd */ nsd->children[i].handler->fd = nsd->children[i].child_fd; break; case 0: /* CHILD */ nsd->pid = 0; nsd->child_count = 0; nsd->server_kind = nsd->children[i].kind; nsd->this_child = &nsd->children[i]; /* remove signal flags inherited from parent the parent will handle them. */ nsd->signal_hint_reload = 0; nsd->signal_hint_child = 0; nsd->signal_hint_quit = 0; nsd->signal_hint_shutdown = 0; nsd->signal_hint_stats = 0; nsd->signal_hint_statsusr = 0; close(nsd->this_child->child_fd); nsd->this_child->child_fd = -1; server_child(nsd); /* NOTREACH */ exit(0); case -1: log_msg(LOG_ERR, "fork failed: %s", strerror(errno)); return -1; } } } return 0; } #ifdef BIND8_STATS static void set_bind8_alarm(struct nsd* nsd) { /* resync so that the next alarm is on the next whole minute */ if(nsd->st.period > 0) /* % by 0 gives divbyzero error */ alarm(nsd->st.period - (time(NULL) % nsd->st.period)); } #endif static void cleanup_dname_compression_tables(void *ptr) { free(ptr); compressed_dname_offsets = NULL; compression_table_capacity = 0; } static void initialize_dname_compression_tables(struct nsd *nsd) { size_t needed = domain_table_count(nsd->db->domains) + 1; needed += EXTRA_DOMAIN_NUMBERS; if(compression_table_capacity < needed) { if(compressed_dname_offsets) { region_remove_cleanup(nsd->db->region, cleanup_dname_compression_tables, compressed_dname_offsets); free(compressed_dname_offsets); } compressed_dname_offsets = (uint16_t *) xalloc( needed * sizeof(uint16_t)); region_add_cleanup(nsd->db->region, cleanup_dname_compression_tables, compressed_dname_offsets); compression_table_capacity = needed; compression_table_size=domain_table_count(nsd->db->domains)+1; } memset(compressed_dname_offsets, 0, needed * sizeof(uint16_t)); compressed_dname_offsets[0] = QHEADERSZ; /* The original query name */ } /* * Initialize the server, create and bind the sockets. * */ int server_init(struct nsd *nsd) { size_t i; #if defined(SO_REUSEADDR) || (defined(INET6) && (defined(IPV6_V6ONLY) || defined(IPV6_USE_MIN_MTU) || defined(IPV6_MTU))) int on = 1; #endif /* UDP */ /* Make a socket... */ for (i = 0; i < nsd->ifs; i++) { if (!nsd->udp[i].addr) { nsd->udp[i].s = -1; continue; } if ((nsd->udp[i].s = socket(nsd->udp[i].addr->ai_family, nsd->udp[i].addr->ai_socktype, 0)) == -1) { #if defined(INET6) if (nsd->udp[i].addr->ai_family == AF_INET6 && errno == EAFNOSUPPORT && nsd->grab_ip6_optional) { log_msg(LOG_WARNING, "fallback to UDP4, no IPv6: not supported"); continue; } #endif /* INET6 */ log_msg(LOG_ERR, "can't create a socket: %s", strerror(errno)); return -1; } #if defined(INET6) if (nsd->udp[i].addr->ai_family == AF_INET6) { # if defined(IPV6_V6ONLY) if (setsockopt(nsd->udp[i].s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) { log_msg(LOG_ERR, "setsockopt(..., IPV6_V6ONLY, ...) failed: %s", strerror(errno)); return -1; } # endif # if defined(IPV6_USE_MIN_MTU) /* * There is no fragmentation of IPv6 datagrams * during forwarding in the network. Therefore * we do not send UDP datagrams larger than * the minimum IPv6 MTU of 1280 octets. The * EDNS0 message length can be larger if the * network stack supports IPV6_USE_MIN_MTU. */ if (setsockopt(nsd->udp[i].s, IPPROTO_IPV6, IPV6_USE_MIN_MTU, &on, sizeof(on)) < 0) { log_msg(LOG_ERR, "setsockopt(..., IPV6_USE_MIN_MTU, ...) failed: %s", strerror(errno)); return -1; } # elif defined(IPV6_MTU) /* * On Linux, PMTUD is disabled by default for datagrams * so set the MTU equal to the MIN MTU to get the same. */ on = IPV6_MIN_MTU; if (setsockopt(nsd->udp[i].s, IPPROTO_IPV6, IPV6_MTU, &on, sizeof(on)) < 0) { log_msg(LOG_ERR, "setsockopt(..., IPV6_MTU, ...) failed: %s", strerror(errno)); return -1; } on = 1; # endif } #endif #if defined(AF_INET) if (nsd->udp[i].addr->ai_family == AF_INET) { # if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT) int action = IP_PMTUDISC_DONT; if (setsockopt(nsd->udp[i].s, IPPROTO_IP, IP_MTU_DISCOVER, &action, sizeof(action)) < 0) { log_msg(LOG_ERR, "setsockopt(..., IP_MTU_DISCOVER, IP_PMTUDISC_DONT...) failed: %s", strerror(errno)); return -1; } # elif defined(IP_DONTFRAG) int off = 0; if (setsockopt(nsd->udp[i].s, IPPROTO_IP, IP_DONTFRAG, &off, sizeof(off)) < 0) { log_msg(LOG_ERR, "setsockopt(..., IP_DONTFRAG, ...) failed: %s", strerror(errno)); return -1; } # endif } #endif /* set it nonblocking */ /* otherwise, on OSes with thundering herd problems, the UDP recv could block NSD after select returns readable. */ if (fcntl(nsd->udp[i].s, F_SETFL, O_NONBLOCK) == -1) { log_msg(LOG_ERR, "cannot fcntl udp: %s", strerror(errno)); } /* Bind it... */ if (bind(nsd->udp[i].s, (struct sockaddr *) nsd->udp[i].addr->ai_addr, nsd->udp[i].addr->ai_addrlen) != 0) { log_msg(LOG_ERR, "can't bind udp socket: %s", strerror(errno)); return -1; } } /* TCP */ /* Make a socket... */ for (i = 0; i < nsd->ifs; i++) { if (!nsd->tcp[i].addr) { nsd->tcp[i].s = -1; continue; } if ((nsd->tcp[i].s = socket(nsd->tcp[i].addr->ai_family, nsd->tcp[i].addr->ai_socktype, 0)) == -1) { #if defined(INET6) if (nsd->tcp[i].addr->ai_family == AF_INET6 && errno == EAFNOSUPPORT && nsd->grab_ip6_optional) { log_msg(LOG_WARNING, "fallback to TCP4, no IPv6: not supported"); continue; } #endif /* INET6 */ log_msg(LOG_ERR, "can't create a socket: %s", strerror(errno)); return -1; } #ifdef SO_REUSEADDR if (setsockopt(nsd->tcp[i].s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) { log_msg(LOG_ERR, "setsockopt(..., SO_REUSEADDR, ...) failed: %s", strerror(errno)); } #endif /* SO_REUSEADDR */ #if defined(INET6) && defined(IPV6_V6ONLY) if (nsd->tcp[i].addr->ai_family == AF_INET6 && setsockopt(nsd->tcp[i].s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) { log_msg(LOG_ERR, "setsockopt(..., IPV6_V6ONLY, ...) failed: %s", strerror(errno)); return -1; } #endif /* set it nonblocking */ /* (StevensUNP p463), if tcp listening socket is blocking, then it may block in accept, even if select() says readable. */ if (fcntl(nsd->tcp[i].s, F_SETFL, O_NONBLOCK) == -1) { log_msg(LOG_ERR, "cannot fcntl tcp: %s", strerror(errno)); } /* Bind it... */ if (bind(nsd->tcp[i].s, (struct sockaddr *) nsd->tcp[i].addr->ai_addr, nsd->tcp[i].addr->ai_addrlen) != 0) { log_msg(LOG_ERR, "can't bind tcp socket: %s", strerror(errno)); return -1; } /* Listen to it... */ if (listen(nsd->tcp[i].s, TCP_BACKLOG) == -1) { log_msg(LOG_ERR, "can't listen: %s", strerror(errno)); return -1; } } return 0; } /* * Prepare the server for take off. * */ int server_prepare(struct nsd *nsd) { #ifdef RATELIMIT /* set secret modifier for hashing (udb ptr buckets and rate limits) */ #ifdef HAVE_ARC4RANDOM srandom(arc4random()); hash_set_raninit(arc4random()); #else uint32_t v = getpid() ^ time(NULL); srandom((unsigned long)v); if(RAND_status() && RAND_bytes((unsigned char*)&v, sizeof(v)) > 0) hash_set_raninit(v); else hash_set_raninit(random()); #endif rrl_mmap_init(nsd->child_count, nsd->options->rrl_size, nsd->options->rrl_ratelimit, nsd->options->rrl_whitelist_ratelimit); #endif /* RATELIMIT */ /* Open the database... */ if ((nsd->db = namedb_open(nsd->dbfile, nsd->options, nsd->child_count)) == NULL) { log_msg(LOG_ERR, "unable to open the database %s: %s", nsd->dbfile, strerror(errno)); return -1; } /* Read diff file */ if(!diff_read_file(nsd->db, nsd->options, NULL, nsd->child_count)) { log_msg(LOG_ERR, "The diff file contains errors. Will continue " "without it"); } #ifdef NSEC3 prehash(nsd->db, 0); #endif compression_table_capacity = 0; initialize_dname_compression_tables(nsd); #ifdef BIND8_STATS /* Initialize times... */ time(&nsd->st.boot); set_bind8_alarm(nsd); #endif /* BIND8_STATS */ return 0; } /* * Fork the required number of servers. */ static int server_start_children(struct nsd *nsd, region_type* region, netio_type* netio, int* xfrd_sock_p) { size_t i; /* Start all child servers initially. */ for (i = 0; i < nsd->child_count; ++i) { nsd->children[i].pid = 0; } return restart_child_servers(nsd, region, netio, xfrd_sock_p); } static void close_all_sockets(struct nsd_socket sockets[], size_t n) { size_t i; /* Close all the sockets... */ for (i = 0; i < n; ++i) { if (sockets[i].s != -1) { close(sockets[i].s); freeaddrinfo(sockets[i].addr); sockets[i].s = -1; } } } /* * Close the sockets, shutdown the server and exit. * Does not return. * */ void server_shutdown(struct nsd *nsd) { size_t i; close_all_sockets(nsd->udp, nsd->ifs); close_all_sockets(nsd->tcp, nsd->ifs); /* CHILD: close command channel to parent */ if(nsd->this_child && nsd->this_child->parent_fd != -1) { close(nsd->this_child->parent_fd); nsd->this_child->parent_fd = -1; } /* SERVER: close command channels to children */ if(!nsd->this_child) { for(i=0; i < nsd->child_count; ++i) if(nsd->children[i].child_fd != -1) { close(nsd->children[i].child_fd); nsd->children[i].child_fd = -1; } } log_finalize(); tsig_finalize(); nsd_options_destroy(nsd->options); region_destroy(nsd->region); exit(0); } static pid_t server_start_xfrd(struct nsd *nsd, netio_handler_type* handler) { pid_t pid; int sockets[2] = {0,0}; zone_type* zone; struct ipc_handler_conn_data *data; /* no need to send updates for zones, because xfrd will read from fork-memory */ for(zone = nsd->db->zones; zone; zone=zone->next) { zone->updated = 0; } if(handler->fd != -1) close(handler->fd); if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) == -1) { log_msg(LOG_ERR, "startxfrd failed on socketpair: %s", strerror(errno)); return -1; } pid = fork(); switch (pid) { case -1: log_msg(LOG_ERR, "fork xfrd failed: %s", strerror(errno)); break; case 0: /* CHILD: close first socket, use second one */ close(sockets[0]); xfrd_init(sockets[1], nsd); /* ENOTREACH */ break; default: /* PARENT: close second socket, use first one */ close(sockets[1]); handler->fd = sockets[0]; break; } /* PARENT only */ handler->timeout = NULL; handler->event_types = NETIO_EVENT_READ; handler->event_handler = parent_handle_xfrd_command; /* clear ongoing ipc reads */ data = (struct ipc_handler_conn_data *) handler->user_data; data->conn->is_reading = 0; return pid; } /* pass timeout=-1 for blocking. Returns size, 0, -1(err), or -2(timeout) */ static ssize_t block_read(struct nsd* nsd, int s, void* p, ssize_t sz, int timeout) { uint8_t* buf = (uint8_t*) p; ssize_t total = 0; fd_set rfds; struct timeval tv; FD_ZERO(&rfds); while( total < sz) { ssize_t ret; FD_SET(s, &rfds); tv.tv_sec = timeout; tv.tv_usec = 0; ret = select(s+1, &rfds, NULL, NULL, timeout==-1?NULL:&tv); if(ret == -1) { if(errno == EAGAIN) /* blocking read */ continue; if(errno == EINTR) { if(nsd && (nsd->signal_hint_quit || nsd->signal_hint_shutdown)) return -1; /* other signals can be handled later */ continue; } /* some error */ return -1; } if(ret == 0) { /* operation timed out */ return -2; } ret = read(s, buf+total, sz-total); if(ret == -1) { if(errno == EAGAIN) /* blocking read */ continue; if(errno == EINTR) { if(nsd && (nsd->signal_hint_quit || nsd->signal_hint_shutdown)) return -1; /* other signals can be handled later */ continue; } /* some error */ return -1; } if(ret == 0) { /* closed connection! */ return 0; } total += ret; } return total; } /* * Reload the database, stop parent, re-fork children and continue. * as server_main. */ static void server_reload(struct nsd *nsd, region_type* server_region, netio_type* netio, int cmdsocket, int* xfrd_sock_p) { pid_t old_pid; sig_atomic_t cmd = NSD_QUIT_SYNC; zone_type* zone; int xfrd_sock = *xfrd_sock_p; int ret; if(db_crc_different(nsd->db) == 0) { DEBUG(DEBUG_XFRD,1, (LOG_INFO, "CRC the same. skipping %s.", nsd->db->filename)); } else { DEBUG(DEBUG_XFRD,1, (LOG_INFO, "CRC different. reread of %s.", nsd->db->filename)); namedb_close(nsd->db); if ((nsd->db = namedb_open(nsd->dbfile, nsd->options, nsd->child_count)) == NULL) { log_msg(LOG_ERR, "unable to reload the database: %s", strerror(errno)); exit(1); } #if defined(NSEC3) && !defined(FULL_PREHASH) prehash(nsd->db, 0); #endif } if(!diff_read_file(nsd->db, nsd->options, NULL, nsd->child_count)) { log_msg(LOG_ERR, "unable to load the diff file: %s", nsd->options->difffile); exit(1); } log_msg(LOG_INFO, "memory recyclebin holds %lu bytes", (unsigned long) region_get_recycle_size(nsd->db->region)); #ifndef NDEBUG if(nsd_debug_level >= 1) region_log_stats(nsd->db->region); #endif /* NDEBUG */ #ifdef NSEC3 #ifdef FULL_PREHASH prehash(nsd->db, 1); #endif /* FULL_PREHASH */ #endif /* NSEC3 */ initialize_dname_compression_tables(nsd); /* Get our new process id */ old_pid = nsd->pid; nsd->pid = getpid(); #ifdef BIND8_STATS /* Restart dumping stats if required. */ time(&nsd->st.boot); set_bind8_alarm(nsd); #endif /* Start new child processes */ if (server_start_children(nsd, server_region, netio, xfrd_sock_p) != 0) { send_children_quit(nsd); exit(1); } /* if the parent has quit, we must quit too, poll the fd for cmds */ if(block_read(nsd, cmdsocket, &cmd, sizeof(cmd), 0) == sizeof(cmd)) { DEBUG(DEBUG_IPC,1, (LOG_INFO, "reload: ipc command from main %d", cmd)); if(cmd == NSD_QUIT) { DEBUG(DEBUG_IPC,1, (LOG_INFO, "reload: quit to follow nsd")); send_children_quit(nsd); exit(0); } } /* Overwrite pid before closing old parent, to avoid race condition: * - parent process already closed * - pidfile still contains old_pid * - control script contacts parent process, using contents of pidfile */ if (writepid(nsd) == -1) { log_msg(LOG_ERR, "cannot overwrite the pidfile %s: %s", nsd->pidfile, strerror(errno)); } #define RELOAD_SYNC_TIMEOUT 25 /* seconds */ /* Send quit command to parent: blocking, wait for receipt. */ do { DEBUG(DEBUG_IPC,1, (LOG_INFO, "reload: ipc send quit to main")); if (!write_socket(cmdsocket, &cmd, sizeof(cmd))) { log_msg(LOG_ERR, "problems sending command from reload %d to oldnsd %d: %s", (int)nsd->pid, (int)old_pid, strerror(errno)); } /* blocking: wait for parent to really quit. (it sends RELOAD as ack) */ DEBUG(DEBUG_IPC,1, (LOG_INFO, "reload: ipc wait for ack main")); ret = block_read(nsd, cmdsocket, &cmd, sizeof(cmd), RELOAD_SYNC_TIMEOUT); if(ret == -2) { DEBUG(DEBUG_IPC, 1, (LOG_ERR, "reload timeout QUITSYNC. retry")); } } while (ret == -2); if(ret == -1) { log_msg(LOG_ERR, "reload: could not wait for parent to quit: %s", strerror(errno)); } DEBUG(DEBUG_IPC,1, (LOG_INFO, "reload: ipc reply main %d %d", ret, cmd)); if(cmd == NSD_QUIT) { /* small race condition possible here, parent got quit cmd. */ send_children_quit(nsd); unlinkpid(nsd->pidfile); exit(1); } assert(ret==-1 || ret == 0 || cmd == NSD_RELOAD); /* inform xfrd of new SOAs */ cmd = NSD_SOA_BEGIN; if(!write_socket(xfrd_sock, &cmd, sizeof(cmd))) { log_msg(LOG_ERR, "problems sending soa begin from reload %d to xfrd: %s", (int)nsd->pid, strerror(errno)); } for(zone= nsd->db->zones; zone; zone = zone->next) { uint16_t sz; const dname_type *dname_ns=0, *dname_em=0; if(zone->updated == 0) continue; DEBUG(DEBUG_IPC,1, (LOG_INFO, "nsd: sending soa info for zone %s", dname_to_string(domain_dname(zone->apex),0))); cmd = NSD_SOA_INFO; sz = dname_total_size(domain_dname(zone->apex)); if(zone->soa_rrset) { dname_ns = domain_dname( rdata_atom_domain(zone->soa_rrset->rrs[0].rdatas[0])); dname_em = domain_dname( rdata_atom_domain(zone->soa_rrset->rrs[0].rdatas[1])); sz += sizeof(uint32_t)*6 + sizeof(uint8_t)*2 + dname_ns->name_size + dname_em->name_size; } sz = htons(sz); /* use blocking writes */ if(!write_socket(xfrd_sock, &cmd, sizeof(cmd)) || !write_socket(xfrd_sock, &sz, sizeof(sz)) || !write_socket(xfrd_sock, domain_dname(zone->apex), dname_total_size(domain_dname(zone->apex)))) { log_msg(LOG_ERR, "problems sending soa info from reload %d to xfrd: %s", (int)nsd->pid, strerror(errno)); } if(zone->soa_rrset) { uint32_t ttl = htonl(zone->soa_rrset->rrs[0].ttl); assert(dname_ns && dname_em); assert(zone->soa_rrset->rr_count > 0); assert(rrset_rrtype(zone->soa_rrset) == TYPE_SOA); assert(zone->soa_rrset->rrs[0].rdata_count == 7); if(!write_socket(xfrd_sock, &ttl, sizeof(uint32_t)) || !write_socket(xfrd_sock, &dname_ns->name_size, sizeof(uint8_t)) || !write_socket(xfrd_sock, dname_name(dname_ns), dname_ns->name_size) || !write_socket(xfrd_sock, &dname_em->name_size, sizeof(uint8_t)) || !write_socket(xfrd_sock, dname_name(dname_em), dname_em->name_size) || !write_socket(xfrd_sock, rdata_atom_data( zone->soa_rrset->rrs[0].rdatas[2]), sizeof(uint32_t)) || !write_socket(xfrd_sock, rdata_atom_data( zone->soa_rrset->rrs[0].rdatas[3]), sizeof(uint32_t)) || !write_socket(xfrd_sock, rdata_atom_data( zone->soa_rrset->rrs[0].rdatas[4]), sizeof(uint32_t)) || !write_socket(xfrd_sock, rdata_atom_data( zone->soa_rrset->rrs[0].rdatas[5]), sizeof(uint32_t)) || !write_socket(xfrd_sock, rdata_atom_data( zone->soa_rrset->rrs[0].rdatas[6]), sizeof(uint32_t))) { log_msg(LOG_ERR, "problems sending soa info from reload %d to xfrd: %s", (int)nsd->pid, strerror(errno)); } } zone->updated = 0; } cmd = NSD_SOA_END; if(!write_socket(xfrd_sock, &cmd, sizeof(cmd))) { log_msg(LOG_ERR, "problems sending soa end from reload %d to xfrd: %s", (int)nsd->pid, strerror(errno)); } /* try to reopen file */ if (nsd->file_rotation_ok) log_reopen(nsd->log_filename, 1); /* exit reload, continue as new server_main */ } /* * Get the mode depending on the signal hints that have been received. * Multiple signal hints can be received and will be handled in turn. */ static sig_atomic_t server_signal_mode(struct nsd *nsd) { if(nsd->signal_hint_quit) { nsd->signal_hint_quit = 0; return NSD_QUIT; } else if(nsd->signal_hint_shutdown) { nsd->signal_hint_shutdown = 0; return NSD_SHUTDOWN; } else if(nsd->signal_hint_child) { nsd->signal_hint_child = 0; return NSD_REAP_CHILDREN; } else if(nsd->signal_hint_reload) { nsd->signal_hint_reload = 0; return NSD_RELOAD; } else if(nsd->signal_hint_stats) { nsd->signal_hint_stats = 0; #ifdef BIND8_STATS set_bind8_alarm(nsd); #endif return NSD_STATS; } else if(nsd->signal_hint_statsusr) { nsd->signal_hint_statsusr = 0; return NSD_STATS; } return NSD_RUN; } /* * The main server simply waits for signals and child processes to * terminate. Child processes are restarted as necessary. */ void server_main(struct nsd *nsd) { region_type *server_region = region_create(xalloc, free); netio_type *netio = netio_create(server_region); netio_handler_type reload_listener; netio_handler_type xfrd_listener; int reload_sockets[2] = {-1, -1}; struct timespec timeout_spec; int fd; int status; pid_t child_pid; pid_t reload_pid = -1; pid_t xfrd_pid = -1; sig_atomic_t mode; #ifdef RATELIMIT rrl_init((nsd->this_child - nsd->children)/sizeof(nsd->children[0])); #endif /* Ensure we are the main process */ assert(nsd->server_kind == NSD_SERVER_MAIN); xfrd_listener.user_data = (struct ipc_handler_conn_data*)region_alloc( server_region, sizeof(struct ipc_handler_conn_data)); xfrd_listener.fd = -1; ((struct ipc_handler_conn_data*)xfrd_listener.user_data)->nsd = nsd; ((struct ipc_handler_conn_data*)xfrd_listener.user_data)->conn = xfrd_tcp_create(server_region); /* Start the XFRD process */ xfrd_pid = server_start_xfrd(nsd, &xfrd_listener); netio_add_handler(netio, &xfrd_listener); /* Start the child processes that handle incoming queries */ if (server_start_children(nsd, server_region, netio, &xfrd_listener.fd) != 0) { send_children_quit(nsd); exit(1); } reload_listener.fd = -1; /* This_child MUST be 0, because this is the parent process */ assert(nsd->this_child == 0); /* Run the server until we get a shutdown signal */ while ((mode = nsd->mode) != NSD_SHUTDOWN) { /* Did we receive a signal that changes our mode? */ if(mode == NSD_RUN) { nsd->mode = mode = server_signal_mode(nsd); } switch (mode) { case NSD_RUN: /* see if any child processes terminated */ while((child_pid = waitpid(0, &status, WNOHANG)) != -1 && child_pid != 0) { int is_child = delete_child_pid(nsd, child_pid); if (is_child != -1 && nsd->children[is_child].need_to_exit) { if(nsd->children[is_child].child_fd == -1) nsd->children[is_child].has_exited = 1; parent_check_all_children_exited(nsd); } else if(is_child != -1) { log_msg(LOG_WARNING, "server %d died unexpectedly with status %d, restarting", (int) child_pid, status); restart_child_servers(nsd, server_region, netio, &xfrd_listener.fd); } else if (child_pid == reload_pid) { sig_atomic_t cmd = NSD_SOA_END; log_msg(LOG_WARNING, "Reload process %d failed with status %d, continuing with old database", (int) child_pid, status); reload_pid = -1; if(reload_listener.fd > 0) close(reload_listener.fd); reload_listener.fd = -1; reload_listener.event_types = NETIO_EVENT_NONE; /* inform xfrd reload attempt ended */ if(!write_socket(xfrd_listener.fd, &cmd, sizeof(cmd))) { log_msg(LOG_ERR, "problems " "sending SOAEND to xfrd: %s", strerror(errno)); } } else if (child_pid == xfrd_pid) { log_msg(LOG_WARNING, "xfrd process %d failed with status %d, restarting ", (int) child_pid, status); xfrd_pid = server_start_xfrd(nsd, &xfrd_listener); } else { log_msg(LOG_WARNING, "Unknown child %d terminated with status %d", (int) child_pid, status); } } if (child_pid == -1) { if (errno == EINTR) { continue; } log_msg(LOG_WARNING, "wait failed: %s", strerror(errno)); } if (nsd->mode != NSD_RUN) break; /* timeout to collect processes. In case no sigchild happens. */ timeout_spec.tv_sec = 60; timeout_spec.tv_nsec = 0; /* listen on ports, timeout for collecting terminated children */ if(netio_dispatch(netio, &timeout_spec, 0) == -1) { if (errno != EINTR) { log_msg(LOG_ERR, "netio_dispatch failed: %s", strerror(errno)); } } break; case NSD_RELOAD: /* Continue to run nsd after reload */ nsd->mode = NSD_RUN; if (reload_pid != -1) { log_msg(LOG_WARNING, "Reload already in progress (pid = %d)", (int) reload_pid); break; } log_msg(LOG_WARNING, "signal received, reloading..."); if (socketpair(AF_UNIX, SOCK_STREAM, 0, reload_sockets) == -1) { log_msg(LOG_ERR, "reload failed on socketpair: %s", strerror(errno)); reload_pid = -1; break; } /* Do actual reload */ reload_pid = fork(); switch (reload_pid) { case -1: log_msg(LOG_ERR, "fork failed: %s", strerror(errno)); break; case 0: /* CHILD */ close(reload_sockets[0]); server_reload(nsd, server_region, netio, reload_sockets[1], &xfrd_listener.fd); DEBUG(DEBUG_IPC,2, (LOG_INFO, "Reload exited to become new main")); close(reload_sockets[1]); DEBUG(DEBUG_IPC,2, (LOG_INFO, "Reload closed")); /* drop stale xfrd ipc data */ ((struct ipc_handler_conn_data*)xfrd_listener.user_data) ->conn->is_reading = 0; reload_pid = -1; reload_listener.fd = -1; reload_listener.event_types = NETIO_EVENT_NONE; DEBUG(DEBUG_IPC,2, (LOG_INFO, "Reload resetup; run")); break; default: /* PARENT, keep running until NSD_QUIT_SYNC * received from CHILD. */ close(reload_sockets[1]); reload_listener.fd = reload_sockets[0]; reload_listener.timeout = NULL; reload_listener.user_data = nsd; reload_listener.event_types = NETIO_EVENT_READ; reload_listener.event_handler = parent_handle_reload_command; /* listens to Quit */ netio_add_handler(netio, &reload_listener); break; } break; case NSD_QUIT_SYNC: /* synchronisation of xfrd, parent and reload */ if(!nsd->quit_sync_done && reload_listener.fd != -1) { sig_atomic_t cmd = NSD_RELOAD; /* stop xfrd ipc writes in progress */ DEBUG(DEBUG_IPC,1, (LOG_INFO, "main: ipc send indication reload")); if(!write_socket(xfrd_listener.fd, &cmd, sizeof(cmd))) { log_msg(LOG_ERR, "server_main: could not send reload " "indication to xfrd: %s", strerror(errno)); } /* wait for ACK from xfrd */ DEBUG(DEBUG_IPC,1, (LOG_INFO, "main: wait ipc reply xfrd")); nsd->quit_sync_done = 1; } nsd->mode = NSD_RUN; break; case NSD_QUIT: /* silent shutdown during reload */ if(reload_listener.fd != -1) { /* acknowledge the quit, to sync reload that we will really quit now */ sig_atomic_t cmd = NSD_RELOAD; DEBUG(DEBUG_IPC,1, (LOG_INFO, "main: ipc ack reload")); if(!write_socket(reload_listener.fd, &cmd, sizeof(cmd))) { log_msg(LOG_ERR, "server_main: " "could not ack quit: %s", strerror(errno)); } close(reload_listener.fd); } /* only quit children after xfrd has acked */ send_children_quit(nsd); namedb_fd_close(nsd->db); region_destroy(server_region); server_shutdown(nsd); /* ENOTREACH */ break; case NSD_SHUTDOWN: send_children_quit(nsd); log_msg(LOG_WARNING, "signal received, shutting down..."); break; case NSD_REAP_CHILDREN: /* continue; wait for child in run loop */ nsd->mode = NSD_RUN; break; case NSD_STATS: #ifdef BIND8_STATS set_children_stats(nsd); #endif nsd->mode = NSD_RUN; break; default: log_msg(LOG_WARNING, "NSD main server mode invalid: %d", nsd->mode); nsd->mode = NSD_RUN; break; } } /* Truncate the pid file. */ if ((fd = open(nsd->pidfile, O_WRONLY | O_TRUNC, 0644)) == -1) { log_msg(LOG_ERR, "can not truncate the pid file %s: %s", nsd->pidfile, strerror(errno)); } else { close(fd); } /* Unlink it if possible... */ unlinkpid(nsd->pidfile); if(reload_listener.fd != -1) { sig_atomic_t cmd = NSD_QUIT; DEBUG(DEBUG_IPC,1, (LOG_INFO, "main: ipc send quit to reload-process")); if(!write_socket(reload_listener.fd, &cmd, sizeof(cmd))) { log_msg(LOG_ERR, "server_main: could not send quit to reload: %s", strerror(errno)); } fsync(reload_listener.fd); close(reload_listener.fd); } if(xfrd_listener.fd != -1) { /* complete quit, stop xfrd */ sig_atomic_t cmd = NSD_QUIT; DEBUG(DEBUG_IPC,1, (LOG_INFO, "main: ipc send quit to xfrd")); if(!write_socket(xfrd_listener.fd, &cmd, sizeof(cmd))) { log_msg(LOG_ERR, "server_main: could not send quit to xfrd: %s", strerror(errno)); } fsync(xfrd_listener.fd); close(xfrd_listener.fd); (void)kill(xfrd_pid, SIGTERM); } namedb_fd_close(nsd->db); region_destroy(server_region); server_shutdown(nsd); } static query_state_type server_process_query(struct nsd *nsd, struct query *query) { return query_process(query, nsd); } /* * Serve DNS requests. */ void server_child(struct nsd *nsd) { size_t i; region_type *server_region = region_create(xalloc, free); netio_type *netio = netio_create(server_region); netio_handler_type *tcp_accept_handlers; query_type *udp_query; sig_atomic_t mode; assert(nsd->server_kind != NSD_SERVER_MAIN); DEBUG(DEBUG_IPC, 2, (LOG_INFO, "child process started")); if (!(nsd->server_kind & NSD_SERVER_TCP)) { close_all_sockets(nsd->tcp, nsd->ifs); } if (!(nsd->server_kind & NSD_SERVER_UDP)) { close_all_sockets(nsd->udp, nsd->ifs); } if (nsd->this_child && nsd->this_child->parent_fd != -1) { netio_handler_type *handler; handler = (netio_handler_type *) region_alloc( server_region, sizeof(netio_handler_type)); handler->fd = nsd->this_child->parent_fd; handler->timeout = NULL; handler->user_data = (struct ipc_handler_conn_data*)region_alloc( server_region, sizeof(struct ipc_handler_conn_data)); ((struct ipc_handler_conn_data*)handler->user_data)->nsd = nsd; ((struct ipc_handler_conn_data*)handler->user_data)->conn = xfrd_tcp_create(server_region); handler->event_types = NETIO_EVENT_READ; handler->event_handler = child_handle_parent_command; netio_add_handler(netio, handler); } if (nsd->server_kind & NSD_SERVER_UDP) { udp_query = query_create(server_region, compressed_dname_offsets, compression_table_size); for (i = 0; i < nsd->ifs; ++i) { struct udp_handler_data *data; netio_handler_type *handler; data = (struct udp_handler_data *) region_alloc( server_region, sizeof(struct udp_handler_data)); data->query = udp_query; data->nsd = nsd; data->socket = &nsd->udp[i]; handler = (netio_handler_type *) region_alloc( server_region, sizeof(netio_handler_type)); handler->fd = nsd->udp[i].s; handler->timeout = NULL; handler->user_data = data; handler->event_types = NETIO_EVENT_READ; handler->event_handler = handle_udp; netio_add_handler(netio, handler); } } /* * Keep track of all the TCP accept handlers so we can enable * and disable them based on the current number of active TCP * connections. */ tcp_accept_handlers = (netio_handler_type *) region_alloc( server_region, nsd->ifs * sizeof(netio_handler_type)); if (nsd->server_kind & NSD_SERVER_TCP) { for (i = 0; i < nsd->ifs; ++i) { struct tcp_accept_handler_data *data; netio_handler_type *handler; data = (struct tcp_accept_handler_data *) region_alloc( server_region, sizeof(struct tcp_accept_handler_data)); data->nsd = nsd; data->socket = &nsd->tcp[i]; data->tcp_accept_handler_count = nsd->ifs; data->tcp_accept_handlers = tcp_accept_handlers; handler = &tcp_accept_handlers[i]; handler->fd = nsd->tcp[i].s; handler->timeout = NULL; handler->user_data = data; handler->event_types = NETIO_EVENT_READ | NETIO_EVENT_ACCEPT; handler->event_handler = handle_tcp_accept; netio_add_handler(netio, handler); } } /* The main loop... */ while ((mode = nsd->mode) != NSD_QUIT) { if(mode == NSD_RUN) nsd->mode = mode = server_signal_mode(nsd); /* Do we need to do the statistics... */ if (mode == NSD_STATS) { #ifdef BIND8_STATS /* Dump the statistics */ bind8_stats(nsd); #else /* !BIND8_STATS */ log_msg(LOG_NOTICE, "Statistics support not enabled at compile time."); #endif /* BIND8_STATS */ nsd->mode = NSD_RUN; } else if (mode == NSD_REAP_CHILDREN) { /* got signal, notify parent. parent reaps terminated children. */ if (nsd->this_child->parent_fd != -1) { sig_atomic_t parent_notify = NSD_REAP_CHILDREN; if (write(nsd->this_child->parent_fd, &parent_notify, sizeof(parent_notify)) == -1) { log_msg(LOG_ERR, "problems sending command from %d to parent: %s", (int) nsd->this_child->pid, strerror(errno)); } } else /* no parent, so reap 'em */ while (waitpid(0, NULL, WNOHANG) > 0) ; nsd->mode = NSD_RUN; } else if(mode == NSD_RUN) { /* Wait for a query... */ if (netio_dispatch(netio, NULL, NULL) == -1) { if (errno != EINTR) { log_msg(LOG_ERR, "netio_dispatch failed: %s", strerror(errno)); break; } } } else if(mode == NSD_QUIT) { /* ignore here, quit */ } else { log_msg(LOG_ERR, "mode bad value %d, back to service.", mode); nsd->mode = NSD_RUN; } } #ifdef BIND8_STATS bind8_stats(nsd); #endif /* BIND8_STATS */ namedb_fd_close(nsd->db); region_destroy(server_region); server_shutdown(nsd); } static query_state_type server_process_query_udp(struct nsd *nsd, struct query *query) { #ifdef RATELIMIT if(query_process(query, nsd) != QUERY_DISCARDED) { if(rrl_process_query(query)) return rrl_slip(query); else return QUERY_PROCESSED; } return QUERY_DISCARDED; #else return query_process(query, nsd); #endif } static void handle_udp(netio_type *ATTR_UNUSED(netio), netio_handler_type *handler, netio_event_types_type event_types) { struct udp_handler_data *data = (struct udp_handler_data *) handler->user_data; int received, sent; struct query *q = data->query; if (!(event_types & NETIO_EVENT_READ)) { return; } /* Account... */ #ifdef BIND8_STATS if (data->socket->addr->ai_family == AF_INET) { STATUP(data->nsd, qudp); } else if (data->socket->addr->ai_family == AF_INET6) { STATUP(data->nsd, qudp6); } #endif /* Initialize the query... */ query_reset(q, UDP_MAX_MESSAGE_LEN, 0); received = recvfrom(handler->fd, buffer_begin(q->packet), buffer_remaining(q->packet), 0, (struct sockaddr *)&q->addr, &q->addrlen); if (received == -1) { if (errno != EAGAIN && errno != EINTR) { log_msg(LOG_ERR, "recvfrom failed: %s", strerror(errno)); STATUP(data->nsd, rxerr); /* No zone statup */ } } else { buffer_skip(q->packet, received); buffer_flip(q->packet); /* Process and answer the query... */ if (server_process_query_udp(data->nsd, q) != QUERY_DISCARDED) { #ifdef BIND8_STATS if (RCODE(q->packet) == RCODE_OK && !AA(q->packet)) { STATUP(data->nsd, nona); # ifdef USE_ZONE_STATS if (q->zone) ZTATUP(q->zone, nona); # endif } # ifdef USE_ZONE_STATS if (q->zone) { if (data->socket->addr->ai_family == AF_INET) { ZTATUP(q->zone, qudp); } else if (data->socket->addr->ai_family == AF_INET6) { ZTATUP(q->zone, qudp6); } } # endif #endif /* Add EDNS0 and TSIG info if necessary. */ query_add_optional(q, data->nsd); buffer_flip(q->packet); sent = sendto(handler->fd, buffer_begin(q->packet), buffer_remaining(q->packet), 0, (struct sockaddr *) &q->addr, q->addrlen); if (sent == -1) { log_msg(LOG_ERR, "sendto failed: %s", strerror(errno)); STATUP(data->nsd, txerr); #ifdef USE_ZONE_STATS if (q->zone) ZTATUP(q->zone, txerr); #endif } else if ((size_t) sent != buffer_remaining(q->packet)) { log_msg(LOG_ERR, "sent %d in place of %d bytes", sent, (int) buffer_remaining(q->packet)); #ifdef BIND8_STATS } else { /* Account the rcode & TC... */ STATUP2(data->nsd, rcode, RCODE(q->packet)); # ifdef USE_ZONE_STATS if (q->zone) ZTATUP2(q->zone, rcode, RCODE(q->packet)); # endif if (TC(q->packet)) { STATUP(data->nsd, truncated); # ifdef USE_ZONE_STATS if (q->zone) ZTATUP(q->zone, truncated); # endif } #endif /* BIND8_STATS */ } #ifdef BIND8_STATS } else { STATUP(data->nsd, dropped); # ifdef USE_ZONE_STATS if (q->zone) { ZTATUP(q->zone, dropped); } # endif #endif } } } static void cleanup_tcp_handler(netio_type *netio, netio_handler_type *handler) { struct tcp_handler_data *data = (struct tcp_handler_data *) handler->user_data; netio_remove_handler(netio, handler); close(handler->fd); slowaccept = 0; /* * Enable the TCP accept handlers when the current number of * TCP connections is about to drop below the maximum number * of TCP connections. */ if (data->nsd->current_tcp_count == data->nsd->maximum_tcp_count) { configure_handler_event_types(data->tcp_accept_handler_count, data->tcp_accept_handlers, NETIO_EVENT_READ); } --data->nsd->current_tcp_count; assert(data->nsd->current_tcp_count >= 0); region_destroy(data->region); } static void handle_tcp_reading(netio_type *netio, netio_handler_type *handler, netio_event_types_type event_types) { struct tcp_handler_data *data = (struct tcp_handler_data *) handler->user_data; ssize_t received; if (event_types & NETIO_EVENT_TIMEOUT) { /* Connection timed out. */ cleanup_tcp_handler(netio, handler); return; } if (data->nsd->tcp_query_count > 0 && data->query_count >= data->nsd->tcp_query_count) { /* No more queries allowed on this tcp connection. */ cleanup_tcp_handler(netio, handler); return; } assert(event_types & NETIO_EVENT_READ); if (data->bytes_transmitted == 0) { query_reset(data->query, TCP_MAX_MESSAGE_LEN, 1); } /* * Check if we received the leading packet length bytes yet. */ if (data->bytes_transmitted < sizeof(uint16_t)) { received = read(handler->fd, (char *) &data->query->tcplen + data->bytes_transmitted, sizeof(uint16_t) - data->bytes_transmitted); if (received == -1) { if (errno == EAGAIN || errno == EINTR) { /* * Read would block, wait until more * data is available. */ return; } else { #ifdef ECONNRESET if (verbosity >= 2 || errno != ECONNRESET) #endif /* ECONNRESET */ log_msg(LOG_ERR, "failed reading from tcp: %s", strerror(errno)); cleanup_tcp_handler(netio, handler); return; } } else if (received == 0) { /* EOF */ cleanup_tcp_handler(netio, handler); return; } data->bytes_transmitted += received; if (data->bytes_transmitted < sizeof(uint16_t)) { /* * Not done with the tcplen yet, wait for more * data to become available. */ return; } assert(data->bytes_transmitted == sizeof(uint16_t)); data->query->tcplen = ntohs(data->query->tcplen); /* * Minimum query size is: * * Size of the header (12) * + Root domain name (1) * + Query class (2) * + Query type (2) */ if (data->query->tcplen < QHEADERSZ + 1 + sizeof(uint16_t) + sizeof(uint16_t)) { VERBOSITY(2, (LOG_WARNING, "packet too small, dropping tcp connection")); cleanup_tcp_handler(netio, handler); return; } if (data->query->tcplen > data->query->maxlen) { VERBOSITY(2, (LOG_WARNING, "insufficient tcp buffer, dropping connection")); cleanup_tcp_handler(netio, handler); return; } buffer_set_limit(data->query->packet, data->query->tcplen); } assert(buffer_remaining(data->query->packet) > 0); /* Read the (remaining) query data. */ received = read(handler->fd, buffer_current(data->query->packet), buffer_remaining(data->query->packet)); if (received == -1) { if (errno == EAGAIN || errno == EINTR) { /* * Read would block, wait until more data is * available. */ return; } else { #ifdef ECONNRESET if (verbosity >= 2 || errno != ECONNRESET) #endif /* ECONNRESET */ log_msg(LOG_ERR, "failed reading from tcp: %s", strerror(errno)); cleanup_tcp_handler(netio, handler); return; } } else if (received == 0) { /* EOF */ cleanup_tcp_handler(netio, handler); return; } data->bytes_transmitted += received; buffer_skip(data->query->packet, received); if (buffer_remaining(data->query->packet) > 0) { /* * Message not yet complete, wait for more data to * become available. */ return; } assert(buffer_position(data->query->packet) == data->query->tcplen); /* Account... */ #ifdef BIND8_STATS # ifndef INET6 STATUP(data->nsd, ctcp); # else if (data->query->addr.ss_family == AF_INET) { STATUP(data->nsd, ctcp); } else if (data->query->addr.ss_family == AF_INET6) { STATUP(data->nsd, ctcp6); } # endif #endif /* BIND8_STATS */ /* We have a complete query, process it. */ /* tcp-query-count: handle query counter ++ */ data->query_count++; buffer_flip(data->query->packet); data->query_state = server_process_query(data->nsd, data->query); if (data->query_state == QUERY_DISCARDED) { /* Drop the packet and the entire connection... */ STATUP(data->nsd, dropped); #if defined(BIND8_STATS) && defined(USE_ZONE_STATS) if (data->query->zone) { ZTATUP(data->query->zone, dropped); } #endif cleanup_tcp_handler(netio, handler); return; } #ifdef BIND8_STATS if (RCODE(data->query->packet) == RCODE_OK && !AA(data->query->packet)) { STATUP(data->nsd, nona); # ifdef USE_ZONE_STATS if (data->query->zone) ZTATUP(data->query->zone, nona); # endif } # ifdef USE_ZONE_STATS if (data->query->zone) { # ifndef INET6 ZTATUP(data->query->zone, ctcp); # else if (data->query->addr.ss_family == AF_INET) { ZTATUP(data->query->zone, ctcp); } else if (data->query->addr.ss_family == AF_INET6) { ZTATUP(data->query->zone, ctcp6); } # endif } # endif /* USE_ZONE_STATS */ #endif /* BIND8_STATS */ query_add_optional(data->query, data->nsd); /* Switch to the tcp write handler. */ buffer_flip(data->query->packet); data->query->tcplen = buffer_remaining(data->query->packet); data->bytes_transmitted = 0; handler->timeout->tv_sec = data->nsd->tcp_timeout; handler->timeout->tv_nsec = 0L; timespec_add(handler->timeout, netio_current_time(netio)); handler->event_types = NETIO_EVENT_WRITE | NETIO_EVENT_TIMEOUT; handler->event_handler = handle_tcp_writing; } static void handle_tcp_writing(netio_type *netio, netio_handler_type *handler, netio_event_types_type event_types) { struct tcp_handler_data *data = (struct tcp_handler_data *) handler->user_data; ssize_t sent; struct query *q = data->query; if (event_types & NETIO_EVENT_TIMEOUT) { /* Connection timed out. */ cleanup_tcp_handler(netio, handler); return; } assert(event_types & NETIO_EVENT_WRITE); if (data->bytes_transmitted < sizeof(q->tcplen)) { /* Writing the response packet length. */ uint16_t n_tcplen = htons(q->tcplen); #ifdef HAVE_WRITEV struct iovec iov[2]; iov[0].iov_base = (uint8_t*)&n_tcplen + data->bytes_transmitted; iov[0].iov_len = sizeof(n_tcplen) - data->bytes_transmitted; iov[1].iov_base = buffer_begin(q->packet); iov[1].iov_len = buffer_limit(q->packet); sent = writev(handler->fd, iov, 2); #else /* HAVE_WRITEV */ sent = write(handler->fd, (const char *) &n_tcplen + data->bytes_transmitted, sizeof(n_tcplen) - data->bytes_transmitted); #endif /* HAVE_WRITEV */ if (sent == -1) { if (errno == EAGAIN || errno == EINTR) { /* * Write would block, wait until * socket becomes writable again. */ return; } else { #ifdef ECONNRESET if(verbosity >= 2 || errno != ECONNRESET) #endif /* ECONNRESET */ #ifdef EPIPE if(verbosity >= 2 || errno != EPIPE) #endif /* EPIPE 'broken pipe' */ log_msg(LOG_ERR, "failed writing to tcp: %s", strerror(errno)); cleanup_tcp_handler(netio, handler); return; } } data->bytes_transmitted += sent; if (data->bytes_transmitted < sizeof(q->tcplen)) { /* * Writing not complete, wait until socket * becomes writable again. */ return; } #ifdef HAVE_WRITEV sent -= sizeof(n_tcplen); /* handle potential 'packet done' code */ goto packet_could_be_done; #endif } sent = write(handler->fd, buffer_current(q->packet), buffer_remaining(q->packet)); if (sent == -1) { if (errno == EAGAIN || errno == EINTR) { /* * Write would block, wait until * socket becomes writable again. */ return; } else { #ifdef ECONNRESET if(verbosity >= 2 || errno != ECONNRESET) #endif /* ECONNRESET */ #ifdef EPIPE if(verbosity >= 2 || errno != EPIPE) #endif /* EPIPE 'broken pipe' */ log_msg(LOG_ERR, "failed writing to tcp: %s", strerror(errno)); cleanup_tcp_handler(netio, handler); return; } } data->bytes_transmitted += sent; #ifdef HAVE_WRITEV packet_could_be_done: #endif buffer_skip(q->packet, sent); if (data->bytes_transmitted < q->tcplen + sizeof(q->tcplen)) { /* * Still more data to write when socket becomes * writable again. */ return; } assert(data->bytes_transmitted == q->tcplen + sizeof(q->tcplen)); if (data->query_state == QUERY_IN_AXFR) { /* Continue processing AXFR and writing back results. */ buffer_clear(q->packet); data->query_state = query_axfr(data->nsd, q); if (data->query_state != QUERY_PROCESSED) { query_add_optional(data->query, data->nsd); /* Reset data. */ buffer_flip(q->packet); q->tcplen = buffer_remaining(q->packet); data->bytes_transmitted = 0; /* Reset timeout. */ handler->timeout->tv_sec = data->nsd->tcp_timeout; handler->timeout->tv_nsec = 0; timespec_add(handler->timeout, netio_current_time(netio)); /* * Write data if/when the socket is writable * again. */ return; } } /* * Done sending, wait for the next request to arrive on the * TCP socket by installing the TCP read handler. */ if (data->nsd->tcp_query_count > 0 && data->query_count >= data->nsd->tcp_query_count) { (void) shutdown(handler->fd, SHUT_WR); } data->bytes_transmitted = 0; handler->timeout->tv_sec = data->nsd->tcp_timeout; handler->timeout->tv_nsec = 0; timespec_add(handler->timeout, netio_current_time(netio)); handler->event_types = NETIO_EVENT_READ | NETIO_EVENT_TIMEOUT; handler->event_handler = handle_tcp_reading; } /* * Handle an incoming TCP connection. The connection is accepted and * a new TCP reader event handler is added to NETIO. The TCP handler * is responsible for cleanup when the connection is closed. */ static void handle_tcp_accept(netio_type *netio, netio_handler_type *handler, netio_event_types_type event_types) { struct tcp_accept_handler_data *data = (struct tcp_accept_handler_data *) handler->user_data; int s; struct tcp_handler_data *tcp_data; region_type *tcp_region; netio_handler_type *tcp_handler; #ifdef INET6 struct sockaddr_storage addr; #else struct sockaddr_in addr; #endif socklen_t addrlen; if (!(event_types & NETIO_EVENT_READ)) { return; } if (data->nsd->current_tcp_count >= data->nsd->maximum_tcp_count) { return; } /* Accept it... */ addrlen = sizeof(addr); s = accept(handler->fd, (struct sockaddr *) &addr, &addrlen); if (s == -1) { /** * EMFILE and ENFILE is a signal that the limit of open * file descriptors has been reached. Pause accept(). * EINTR is a signal interrupt. The others are various OS ways * of saying that the client has closed the connection. */ if (errno == EMFILE || errno == ENFILE) { if (!slowaccept) { slowaccept_timeout.tv_sec = NETIO_SLOW_ACCEPT_TIMEOUT; slowaccept_timeout.tv_nsec = 0L; timespec_add(&slowaccept_timeout, netio_current_time(netio)); slowaccept = 1; /* We don't want to spam the logs here */ } } else if (errno != EINTR && errno != EWOULDBLOCK #ifdef ECONNABORTED && errno != ECONNABORTED #endif /* ECONNABORTED */ #ifdef EPROTO && errno != EPROTO #endif /* EPROTO */ ) { log_msg(LOG_ERR, "accept failed: %s", strerror(errno)); } return; } if (fcntl(s, F_SETFL, O_NONBLOCK) == -1) { log_msg(LOG_ERR, "fcntl failed: %s", strerror(errno)); close(s); return; } /* * This region is deallocated when the TCP connection is * closed by the TCP handler. */ tcp_region = region_create(xalloc, free); tcp_data = (struct tcp_handler_data *) region_alloc( tcp_region, sizeof(struct tcp_handler_data)); tcp_data->region = tcp_region; tcp_data->query = query_create(tcp_region, compressed_dname_offsets, compression_table_size); tcp_data->nsd = data->nsd; tcp_data->query_count = 0; tcp_data->tcp_accept_handler_count = data->tcp_accept_handler_count; tcp_data->tcp_accept_handlers = data->tcp_accept_handlers; tcp_data->query_state = QUERY_PROCESSED; tcp_data->bytes_transmitted = 0; memcpy(&tcp_data->query->addr, &addr, addrlen); tcp_data->query->addrlen = addrlen; tcp_handler = (netio_handler_type *) region_alloc( tcp_region, sizeof(netio_handler_type)); tcp_handler->fd = s; tcp_handler->timeout = (struct timespec *) region_alloc( tcp_region, sizeof(struct timespec)); tcp_handler->timeout->tv_sec = data->nsd->tcp_timeout; tcp_handler->timeout->tv_nsec = 0L; timespec_add(tcp_handler->timeout, netio_current_time(netio)); tcp_handler->user_data = tcp_data; tcp_handler->event_types = NETIO_EVENT_READ | NETIO_EVENT_TIMEOUT; tcp_handler->event_handler = handle_tcp_reading; netio_add_handler(netio, tcp_handler); /* * Keep track of the total number of TCP handlers installed so * we can stop accepting connections when the maximum number * of simultaneous TCP connections is reached. */ ++data->nsd->current_tcp_count; if (data->nsd->current_tcp_count == data->nsd->maximum_tcp_count) { configure_handler_event_types(data->tcp_accept_handler_count, data->tcp_accept_handlers, NETIO_EVENT_NONE); } } static void send_children_quit(struct nsd* nsd) { sig_atomic_t command = NSD_QUIT; size_t i; assert(nsd->server_kind == NSD_SERVER_MAIN && nsd->this_child == 0); for (i = 0; i < nsd->child_count; ++i) { if (nsd->children[i].pid > 0 && nsd->children[i].child_fd != -1) { if (write(nsd->children[i].child_fd, &command, sizeof(command)) == -1) { if(errno != EAGAIN && errno != EINTR) log_msg(LOG_ERR, "problems sending command %d to server %d: %s", (int) command, (int) nsd->children[i].pid, strerror(errno)); } fsync(nsd->children[i].child_fd); close(nsd->children[i].child_fd); nsd->children[i].child_fd = -1; } } } #ifdef BIND8_STATS static void set_children_stats(struct nsd* nsd) { size_t i; assert(nsd->server_kind == NSD_SERVER_MAIN && nsd->this_child == 0); DEBUG(DEBUG_IPC, 1, (LOG_INFO, "parent set stats to send to children")); for (i = 0; i < nsd->child_count; ++i) { nsd->children[i].need_to_send_STATS = 1; nsd->children[i].handler->event_types |= NETIO_EVENT_WRITE; } } #endif /* BIND8_STATS */ static void configure_handler_event_types(size_t count, netio_handler_type *handlers, netio_event_types_type event_types) { size_t i; assert(handlers); for (i = 0; i < count; ++i) { handlers[i].event_types = event_types; } }