/* * services/outside_network.c - implement sending of queries and wait answer. * * Copyright (c) 2007, NLnet Labs. All rights reserved. * * This software is open source. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the NLNET LABS nor the names of its contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** * \file * * This file has functions to send queries to authoritative servers and * wait for the pending answer events. */ #include "config.h" #include #ifdef HAVE_SYS_TYPES_H # include #endif #include #include "services/outside_network.h" #include "services/listen_dnsport.h" #include "services/cache/infra.h" #include "util/data/msgparse.h" #include "util/data/msgreply.h" #include "util/data/msgencode.h" #include "util/data/dname.h" #include "util/netevent.h" #include "util/log.h" #include "util/net_help.h" #include "util/random.h" #include "util/fptr_wlist.h" #include "sldns/sbuffer.h" #include "dnstap/dnstap.h" #ifdef HAVE_OPENSSL_SSL_H #include #endif #ifdef HAVE_NETDB_H #include #endif #include /** number of times to retry making a random ID that is unique. */ #define MAX_ID_RETRY 1000 /** number of times to retry finding interface, port that can be opened. */ #define MAX_PORT_RETRY 10000 /** number of retries on outgoing UDP queries */ #define OUTBOUND_UDP_RETRY 1 /** initiate TCP transaction for serviced query */ static void serviced_tcp_initiate(struct serviced_query* sq, sldns_buffer* buff); /** with a fd available, randomize and send UDP */ static int randomize_and_send_udp(struct pending* pend, sldns_buffer* packet, int timeout); /** remove waiting tcp from the outnet waiting list */ static void waiting_list_remove(struct outside_network* outnet, struct waiting_tcp* w); int pending_cmp(const void* key1, const void* key2) { struct pending *p1 = (struct pending*)key1; struct pending *p2 = (struct pending*)key2; if(p1->id < p2->id) return -1; if(p1->id > p2->id) return 1; log_assert(p1->id == p2->id); return sockaddr_cmp(&p1->addr, p1->addrlen, &p2->addr, p2->addrlen); } int serviced_cmp(const void* key1, const void* key2) { struct serviced_query* q1 = (struct serviced_query*)key1; struct serviced_query* q2 = (struct serviced_query*)key2; int r; if(q1->qbuflen < q2->qbuflen) return -1; if(q1->qbuflen > q2->qbuflen) return 1; log_assert(q1->qbuflen == q2->qbuflen); log_assert(q1->qbuflen >= 15 /* 10 header, root, type, class */); /* alternate casing of qname is still the same query */ if((r = memcmp(q1->qbuf, q2->qbuf, 10)) != 0) return r; if((r = memcmp(q1->qbuf+q1->qbuflen-4, q2->qbuf+q2->qbuflen-4, 4)) != 0) return r; if(q1->dnssec != q2->dnssec) { if(q1->dnssec < q2->dnssec) return -1; return 1; } if((r = query_dname_compare(q1->qbuf+10, q2->qbuf+10)) != 0) return r; if((r = edns_opt_list_compare(q1->opt_list, q2->opt_list)) != 0) return r; return sockaddr_cmp(&q1->addr, q1->addrlen, &q2->addr, q2->addrlen); } /** delete waiting_tcp entry. Does not unlink from waiting list. * @param w: to delete. */ static void waiting_tcp_delete(struct waiting_tcp* w) { if(!w) return; if(w->timer) comm_timer_delete(w->timer); free(w); } /** * Pick random outgoing-interface of that family, and bind it. * port set to 0 so OS picks a port number for us. * if it is the ANY address, do not bind. * @param w: tcp structure with destination address. * @param s: socket fd. * @return false on error, socket closed. */ static int pick_outgoing_tcp(struct waiting_tcp* w, int s) { struct port_if* pi = NULL; int num; #ifdef INET6 if(addr_is_ip6(&w->addr, w->addrlen)) num = w->outnet->num_ip6; else #endif num = w->outnet->num_ip4; if(num == 0) { log_err("no TCP outgoing interfaces of family"); log_addr(VERB_OPS, "for addr", &w->addr, w->addrlen); #ifndef USE_WINSOCK close(s); #else closesocket(s); #endif return 0; } #ifdef INET6 if(addr_is_ip6(&w->addr, w->addrlen)) pi = &w->outnet->ip6_ifs[ub_random_max(w->outnet->rnd, num)]; else #endif pi = &w->outnet->ip4_ifs[ub_random_max(w->outnet->rnd, num)]; log_assert(pi); if(addr_is_any(&pi->addr, pi->addrlen)) { /* binding to the ANY interface is for listening sockets */ return 1; } /* set port to 0 */ if(addr_is_ip6(&pi->addr, pi->addrlen)) ((struct sockaddr_in6*)&pi->addr)->sin6_port = 0; else ((struct sockaddr_in*)&pi->addr)->sin_port = 0; if(bind(s, (struct sockaddr*)&pi->addr, pi->addrlen) != 0) { #ifndef USE_WINSOCK log_err("outgoing tcp: bind: %s", strerror(errno)); close(s); #else log_err("outgoing tcp: bind: %s", wsa_strerror(WSAGetLastError())); closesocket(s); #endif return 0; } log_addr(VERB_ALGO, "tcp bound to src", &pi->addr, pi->addrlen); return 1; } /** use next free buffer to service a tcp query */ static int outnet_tcp_take_into_use(struct waiting_tcp* w, uint8_t* pkt, size_t pkt_len) { struct pending_tcp* pend = w->outnet->tcp_free; int s; log_assert(pend); log_assert(pkt); log_assert(w->addrlen > 0); /* open socket */ #ifdef INET6 if(addr_is_ip6(&w->addr, w->addrlen)) s = socket(PF_INET6, SOCK_STREAM, IPPROTO_TCP); else #endif s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP); if(s == -1) { #ifndef USE_WINSOCK log_err_addr("outgoing tcp: socket", strerror(errno), &w->addr, w->addrlen); #else log_err_addr("outgoing tcp: socket", wsa_strerror(WSAGetLastError()), &w->addr, w->addrlen); #endif return 0; } if (w->outnet->tcp_mss > 0) { #if defined(IPPROTO_TCP) && defined(TCP_MAXSEG) if(setsockopt(s, IPPROTO_TCP, TCP_MAXSEG, (void*)&w->outnet->tcp_mss, (socklen_t)sizeof(w->outnet->tcp_mss)) < 0) { verbose(VERB_ALGO, "outgoing tcp:" " setsockopt(.. SO_REUSEADDR ..) failed"); } #else verbose(VERB_ALGO, "outgoing tcp:" " setsockopt(TCP_MAXSEG) unsupported"); #endif /* defined(IPPROTO_TCP) && defined(TCP_MAXSEG) */ } if(!pick_outgoing_tcp(w, s)) return 0; fd_set_nonblock(s); #ifdef USE_OSX_MSG_FASTOPEN /* API for fast open is different here. We use a connectx() function and then writes can happen as normal even using SSL.*/ /* connectx requires that the len be set in the sockaddr struct*/ struct sockaddr_in *addr_in = (struct sockaddr_in *)&w->addr; addr_in->sin_len = w->addrlen; sa_endpoints_t endpoints; endpoints.sae_srcif = 0; endpoints.sae_srcaddr = NULL; endpoints.sae_srcaddrlen = 0; endpoints.sae_dstaddr = (struct sockaddr *)&w->addr; endpoints.sae_dstaddrlen = w->addrlen; if (connectx(s, &endpoints, SAE_ASSOCID_ANY, CONNECT_DATA_IDEMPOTENT | CONNECT_RESUME_ON_READ_WRITE, NULL, 0, NULL, NULL) == -1) { #else /* USE_OSX_MSG_FASTOPEN*/ #ifdef USE_MSG_FASTOPEN pend->c->tcp_do_fastopen = 1; /* Only do TFO for TCP in which case no connect() is required here. Don't combine client TFO with SSL, since OpenSSL can't currently support doing a handshake on fd that already isn't connected*/ if (w->outnet->sslctx && w->ssl_upstream) { if(connect(s, (struct sockaddr*)&w->addr, w->addrlen) == -1) { #else /* USE_MSG_FASTOPEN*/ if(connect(s, (struct sockaddr*)&w->addr, w->addrlen) == -1) { #endif /* USE_MSG_FASTOPEN*/ #endif /* USE_OSX_MSG_FASTOPEN*/ #ifndef USE_WINSOCK #ifdef EINPROGRESS if(errno != EINPROGRESS) { #else if(1) { #endif if(tcp_connect_errno_needs_log( (struct sockaddr*)&w->addr, w->addrlen)) log_err_addr("outgoing tcp: connect", strerror(errno), &w->addr, w->addrlen); close(s); #else /* USE_WINSOCK */ if(WSAGetLastError() != WSAEINPROGRESS && WSAGetLastError() != WSAEWOULDBLOCK) { closesocket(s); #endif return 0; } } #ifdef USE_MSG_FASTOPEN } #endif /* USE_MSG_FASTOPEN */ if(w->outnet->sslctx && w->ssl_upstream) { pend->c->ssl = outgoing_ssl_fd(w->outnet->sslctx, s); if(!pend->c->ssl) { pend->c->fd = s; comm_point_close(pend->c); return 0; } #ifdef USE_WINSOCK comm_point_tcp_win_bio_cb(pend->c, pend->c->ssl); #endif pend->c->ssl_shake_state = comm_ssl_shake_write; } w->pkt = NULL; w->next_waiting = (void*)pend; pend->id = LDNS_ID_WIRE(pkt); w->outnet->num_tcp_outgoing++; w->outnet->tcp_free = pend->next_free; pend->next_free = NULL; pend->query = w; pend->c->repinfo.addrlen = w->addrlen; memcpy(&pend->c->repinfo.addr, &w->addr, w->addrlen); sldns_buffer_clear(pend->c->buffer); sldns_buffer_write(pend->c->buffer, pkt, pkt_len); sldns_buffer_flip(pend->c->buffer); pend->c->tcp_is_reading = 0; pend->c->tcp_byte_count = 0; comm_point_start_listening(pend->c, s, -1); return 1; } /** see if buffers can be used to service TCP queries */ static void use_free_buffer(struct outside_network* outnet) { struct waiting_tcp* w; while(outnet->tcp_free && outnet->tcp_wait_first && !outnet->want_to_quit) { w = outnet->tcp_wait_first; outnet->tcp_wait_first = w->next_waiting; if(outnet->tcp_wait_last == w) outnet->tcp_wait_last = NULL; if(!outnet_tcp_take_into_use(w, w->pkt, w->pkt_len)) { comm_point_callback_type* cb = w->cb; void* cb_arg = w->cb_arg; waiting_tcp_delete(w); fptr_ok(fptr_whitelist_pending_tcp(cb)); (void)(*cb)(NULL, cb_arg, NETEVENT_CLOSED, NULL); } } } /** decomission a tcp buffer, closes commpoint and frees waiting_tcp entry */ static void decomission_pending_tcp(struct outside_network* outnet, struct pending_tcp* pend) { if(pend->c->ssl) { #ifdef HAVE_SSL SSL_shutdown(pend->c->ssl); SSL_free(pend->c->ssl); pend->c->ssl = NULL; #endif } comm_point_close(pend->c); pend->next_free = outnet->tcp_free; outnet->tcp_free = pend; waiting_tcp_delete(pend->query); pend->query = NULL; use_free_buffer(outnet); } int outnet_tcp_cb(struct comm_point* c, void* arg, int error, struct comm_reply *reply_info) { struct pending_tcp* pend = (struct pending_tcp*)arg; struct outside_network* outnet = pend->query->outnet; verbose(VERB_ALGO, "outnettcp cb"); if(error != NETEVENT_NOERROR) { verbose(VERB_QUERY, "outnettcp got tcp error %d", error); /* pass error below and exit */ } else { /* check ID */ if(sldns_buffer_limit(c->buffer) < sizeof(uint16_t) || LDNS_ID_WIRE(sldns_buffer_begin(c->buffer))!=pend->id) { log_addr(VERB_QUERY, "outnettcp: bad ID in reply, from:", &pend->query->addr, pend->query->addrlen); error = NETEVENT_CLOSED; } } fptr_ok(fptr_whitelist_pending_tcp(pend->query->cb)); (void)(*pend->query->cb)(c, pend->query->cb_arg, error, reply_info); decomission_pending_tcp(outnet, pend); return 0; } /** lower use count on pc, see if it can be closed */ static void portcomm_loweruse(struct outside_network* outnet, struct port_comm* pc) { struct port_if* pif; pc->num_outstanding--; if(pc->num_outstanding > 0) { return; } /* close it and replace in unused list */ verbose(VERB_ALGO, "close of port %d", pc->number); comm_point_close(pc->cp); pif = pc->pif; log_assert(pif->inuse > 0); pif->avail_ports[pif->avail_total - pif->inuse] = pc->number; pif->inuse--; pif->out[pc->index] = pif->out[pif->inuse]; pif->out[pc->index]->index = pc->index; pc->next = outnet->unused_fds; outnet->unused_fds = pc; } /** try to send waiting UDP queries */ static void outnet_send_wait_udp(struct outside_network* outnet) { struct pending* pend; /* process waiting queries */ while(outnet->udp_wait_first && outnet->unused_fds && !outnet->want_to_quit) { pend = outnet->udp_wait_first; outnet->udp_wait_first = pend->next_waiting; if(!pend->next_waiting) outnet->udp_wait_last = NULL; sldns_buffer_clear(outnet->udp_buff); sldns_buffer_write(outnet->udp_buff, pend->pkt, pend->pkt_len); sldns_buffer_flip(outnet->udp_buff); free(pend->pkt); /* freeing now makes get_mem correct */ pend->pkt = NULL; pend->pkt_len = 0; if(!randomize_and_send_udp(pend, outnet->udp_buff, pend->timeout)) { /* callback error on pending */ if(pend->cb) { fptr_ok(fptr_whitelist_pending_udp(pend->cb)); (void)(*pend->cb)(outnet->unused_fds->cp, pend->cb_arg, NETEVENT_CLOSED, NULL); } pending_delete(outnet, pend); } } } int outnet_udp_cb(struct comm_point* c, void* arg, int error, struct comm_reply *reply_info) { struct outside_network* outnet = (struct outside_network*)arg; struct pending key; struct pending* p; verbose(VERB_ALGO, "answer cb"); if(error != NETEVENT_NOERROR) { verbose(VERB_QUERY, "outnetudp got udp error %d", error); return 0; } if(sldns_buffer_limit(c->buffer) < LDNS_HEADER_SIZE) { verbose(VERB_QUERY, "outnetudp udp too short"); return 0; } log_assert(reply_info); /* setup lookup key */ key.id = (unsigned)LDNS_ID_WIRE(sldns_buffer_begin(c->buffer)); memcpy(&key.addr, &reply_info->addr, reply_info->addrlen); key.addrlen = reply_info->addrlen; verbose(VERB_ALGO, "Incoming reply id = %4.4x", key.id); log_addr(VERB_ALGO, "Incoming reply addr =", &reply_info->addr, reply_info->addrlen); /* find it, see if this thing is a valid query response */ verbose(VERB_ALGO, "lookup size is %d entries", (int)outnet->pending->count); p = (struct pending*)rbtree_search(outnet->pending, &key); if(!p) { verbose(VERB_QUERY, "received unwanted or unsolicited udp reply dropped."); log_buf(VERB_ALGO, "dropped message", c->buffer); outnet->unwanted_replies++; if(outnet->unwanted_threshold && ++outnet->unwanted_total >= outnet->unwanted_threshold) { log_warn("unwanted reply total reached threshold (%u)" " you may be under attack." " defensive action: clearing the cache", (unsigned)outnet->unwanted_threshold); fptr_ok(fptr_whitelist_alloc_cleanup( outnet->unwanted_action)); (*outnet->unwanted_action)(outnet->unwanted_param); outnet->unwanted_total = 0; } return 0; } verbose(VERB_ALGO, "received udp reply."); log_buf(VERB_ALGO, "udp message", c->buffer); if(p->pc->cp != c) { verbose(VERB_QUERY, "received reply id,addr on wrong port. " "dropped."); outnet->unwanted_replies++; if(outnet->unwanted_threshold && ++outnet->unwanted_total >= outnet->unwanted_threshold) { log_warn("unwanted reply total reached threshold (%u)" " you may be under attack." " defensive action: clearing the cache", (unsigned)outnet->unwanted_threshold); fptr_ok(fptr_whitelist_alloc_cleanup( outnet->unwanted_action)); (*outnet->unwanted_action)(outnet->unwanted_param); outnet->unwanted_total = 0; } return 0; } comm_timer_disable(p->timer); verbose(VERB_ALGO, "outnet handle udp reply"); /* delete from tree first in case callback creates a retry */ (void)rbtree_delete(outnet->pending, p->node.key); if(p->cb) { fptr_ok(fptr_whitelist_pending_udp(p->cb)); (void)(*p->cb)(p->pc->cp, p->cb_arg, NETEVENT_NOERROR, reply_info); } portcomm_loweruse(outnet, p->pc); pending_delete(NULL, p); outnet_send_wait_udp(outnet); return 0; } /** calculate number of ip4 and ip6 interfaces*/ static void calc_num46(char** ifs, int num_ifs, int do_ip4, int do_ip6, int* num_ip4, int* num_ip6) { int i; *num_ip4 = 0; *num_ip6 = 0; if(num_ifs <= 0) { if(do_ip4) *num_ip4 = 1; if(do_ip6) *num_ip6 = 1; return; } for(i=0; ioutnet; verbose(VERB_ALGO, "timeout udp with delay"); portcomm_loweruse(outnet, p->pc); pending_delete(outnet, p); outnet_send_wait_udp(outnet); } void pending_udp_timer_cb(void *arg) { struct pending* p = (struct pending*)arg; struct outside_network* outnet = p->outnet; /* it timed out */ verbose(VERB_ALGO, "timeout udp"); if(p->cb) { fptr_ok(fptr_whitelist_pending_udp(p->cb)); (void)(*p->cb)(p->pc->cp, p->cb_arg, NETEVENT_TIMEOUT, NULL); } /* if delayclose, keep port open for a longer time. * But if the udpwaitlist exists, then we are struggling to * keep up with demand for sockets, so do not wait, but service * the customer (customer service more important than portICMPs) */ if(outnet->delayclose && !outnet->udp_wait_first) { p->cb = NULL; p->timer->callback = &pending_udp_timer_delay_cb; comm_timer_set(p->timer, &outnet->delay_tv); return; } portcomm_loweruse(outnet, p->pc); pending_delete(outnet, p); outnet_send_wait_udp(outnet); } /** create pending_tcp buffers */ static int create_pending_tcp(struct outside_network* outnet, size_t bufsize) { size_t i; if(outnet->num_tcp == 0) return 1; /* no tcp needed, nothing to do */ if(!(outnet->tcp_conns = (struct pending_tcp **)calloc( outnet->num_tcp, sizeof(struct pending_tcp*)))) return 0; for(i=0; inum_tcp; i++) { if(!(outnet->tcp_conns[i] = (struct pending_tcp*)calloc(1, sizeof(struct pending_tcp)))) return 0; outnet->tcp_conns[i]->next_free = outnet->tcp_free; outnet->tcp_free = outnet->tcp_conns[i]; outnet->tcp_conns[i]->c = comm_point_create_tcp_out( outnet->base, bufsize, outnet_tcp_cb, outnet->tcp_conns[i]); if(!outnet->tcp_conns[i]->c) return 0; } return 1; } /** setup an outgoing interface, ready address */ static int setup_if(struct port_if* pif, const char* addrstr, int* avail, int numavail, size_t numfd) { pif->avail_total = numavail; pif->avail_ports = (int*)memdup(avail, (size_t)numavail*sizeof(int)); if(!pif->avail_ports) return 0; if(!ipstrtoaddr(addrstr, UNBOUND_DNS_PORT, &pif->addr, &pif->addrlen) && !netblockstrtoaddr(addrstr, UNBOUND_DNS_PORT, &pif->addr, &pif->addrlen, &pif->pfxlen)) return 0; pif->maxout = (int)numfd; pif->inuse = 0; pif->out = (struct port_comm**)calloc(numfd, sizeof(struct port_comm*)); if(!pif->out) return 0; return 1; } struct outside_network* outside_network_create(struct comm_base *base, size_t bufsize, size_t num_ports, char** ifs, int num_ifs, int do_ip4, int do_ip6, size_t num_tcp, struct infra_cache* infra, struct ub_randstate* rnd, int use_caps_for_id, int* availports, int numavailports, size_t unwanted_threshold, int tcp_mss, void (*unwanted_action)(void*), void* unwanted_param, int do_udp, void* sslctx, int delayclose, struct dt_env* dtenv) { struct outside_network* outnet = (struct outside_network*) calloc(1, sizeof(struct outside_network)); size_t k; if(!outnet) { log_err("malloc failed"); return NULL; } comm_base_timept(base, &outnet->now_secs, &outnet->now_tv); outnet->base = base; outnet->num_tcp = num_tcp; outnet->num_tcp_outgoing = 0; outnet->infra = infra; outnet->rnd = rnd; outnet->sslctx = sslctx; #ifdef USE_DNSTAP outnet->dtenv = dtenv; #else (void)dtenv; #endif outnet->svcd_overhead = 0; outnet->want_to_quit = 0; outnet->unwanted_threshold = unwanted_threshold; outnet->unwanted_action = unwanted_action; outnet->unwanted_param = unwanted_param; outnet->use_caps_for_id = use_caps_for_id; outnet->do_udp = do_udp; outnet->tcp_mss = tcp_mss; #ifndef S_SPLINT_S if(delayclose) { outnet->delayclose = 1; outnet->delay_tv.tv_sec = delayclose/1000; outnet->delay_tv.tv_usec = (delayclose%1000)*1000; } #endif if(numavailports == 0) { log_err("no outgoing ports available"); outside_network_delete(outnet); return NULL; } #ifndef INET6 do_ip6 = 0; #endif calc_num46(ifs, num_ifs, do_ip4, do_ip6, &outnet->num_ip4, &outnet->num_ip6); if(outnet->num_ip4 != 0) { if(!(outnet->ip4_ifs = (struct port_if*)calloc( (size_t)outnet->num_ip4, sizeof(struct port_if)))) { log_err("malloc failed"); outside_network_delete(outnet); return NULL; } } if(outnet->num_ip6 != 0) { if(!(outnet->ip6_ifs = (struct port_if*)calloc( (size_t)outnet->num_ip6, sizeof(struct port_if)))) { log_err("malloc failed"); outside_network_delete(outnet); return NULL; } } if( !(outnet->udp_buff = sldns_buffer_new(bufsize)) || !(outnet->pending = rbtree_create(pending_cmp)) || !(outnet->serviced = rbtree_create(serviced_cmp)) || !create_pending_tcp(outnet, bufsize)) { log_err("malloc failed"); outside_network_delete(outnet); return NULL; } /* allocate commpoints */ for(k=0; kcp = comm_point_create_udp(outnet->base, -1, outnet->udp_buff, outnet_udp_cb, outnet); if(!pc->cp) { log_err("malloc failed"); free(pc); outside_network_delete(outnet); return NULL; } pc->next = outnet->unused_fds; outnet->unused_fds = pc; } /* allocate interfaces */ if(num_ifs == 0) { if(do_ip4 && !setup_if(&outnet->ip4_ifs[0], "0.0.0.0", availports, numavailports, num_ports)) { log_err("malloc failed"); outside_network_delete(outnet); return NULL; } if(do_ip6 && !setup_if(&outnet->ip6_ifs[0], "::", availports, numavailports, num_ports)) { log_err("malloc failed"); outside_network_delete(outnet); return NULL; } } else { size_t done_4 = 0, done_6 = 0; int i; for(i=0; iip6_ifs[done_6], ifs[i], availports, numavailports, num_ports)){ log_err("malloc failed"); outside_network_delete(outnet); return NULL; } done_6++; } if(!str_is_ip6(ifs[i]) && do_ip4) { if(!setup_if(&outnet->ip4_ifs[done_4], ifs[i], availports, numavailports, num_ports)){ log_err("malloc failed"); outside_network_delete(outnet); return NULL; } done_4++; } } } return outnet; } /** helper pending delete */ static void pending_node_del(rbnode_type* node, void* arg) { struct pending* pend = (struct pending*)node; struct outside_network* outnet = (struct outside_network*)arg; pending_delete(outnet, pend); } /** helper serviced delete */ static void serviced_node_del(rbnode_type* node, void* ATTR_UNUSED(arg)) { struct serviced_query* sq = (struct serviced_query*)node; struct service_callback* p = sq->cblist, *np; free(sq->qbuf); free(sq->zone); edns_opt_list_free(sq->opt_list); while(p) { np = p->next; free(p); p = np; } free(sq); } void outside_network_quit_prepare(struct outside_network* outnet) { if(!outnet) return; /* prevent queued items from being sent */ outnet->want_to_quit = 1; } void outside_network_delete(struct outside_network* outnet) { if(!outnet) return; outnet->want_to_quit = 1; /* check every element, since we can be called on malloc error */ if(outnet->pending) { /* free pending elements, but do no unlink from tree. */ traverse_postorder(outnet->pending, pending_node_del, NULL); free(outnet->pending); } if(outnet->serviced) { traverse_postorder(outnet->serviced, serviced_node_del, NULL); free(outnet->serviced); } if(outnet->udp_buff) sldns_buffer_free(outnet->udp_buff); if(outnet->unused_fds) { struct port_comm* p = outnet->unused_fds, *np; while(p) { np = p->next; comm_point_delete(p->cp); free(p); p = np; } outnet->unused_fds = NULL; } if(outnet->ip4_ifs) { int i, k; for(i=0; inum_ip4; i++) { for(k=0; kip4_ifs[i].inuse; k++) { struct port_comm* pc = outnet->ip4_ifs[i]. out[k]; comm_point_delete(pc->cp); free(pc); } free(outnet->ip4_ifs[i].avail_ports); free(outnet->ip4_ifs[i].out); } free(outnet->ip4_ifs); } if(outnet->ip6_ifs) { int i, k; for(i=0; inum_ip6; i++) { for(k=0; kip6_ifs[i].inuse; k++) { struct port_comm* pc = outnet->ip6_ifs[i]. out[k]; comm_point_delete(pc->cp); free(pc); } free(outnet->ip6_ifs[i].avail_ports); free(outnet->ip6_ifs[i].out); } free(outnet->ip6_ifs); } if(outnet->tcp_conns) { size_t i; for(i=0; inum_tcp; i++) if(outnet->tcp_conns[i]) { comm_point_delete(outnet->tcp_conns[i]->c); waiting_tcp_delete(outnet->tcp_conns[i]->query); free(outnet->tcp_conns[i]); } free(outnet->tcp_conns); } if(outnet->tcp_wait_first) { struct waiting_tcp* p = outnet->tcp_wait_first, *np; while(p) { np = p->next_waiting; waiting_tcp_delete(p); p = np; } } if(outnet->udp_wait_first) { struct pending* p = outnet->udp_wait_first, *np; while(p) { np = p->next_waiting; pending_delete(NULL, p); p = np; } } free(outnet); } void pending_delete(struct outside_network* outnet, struct pending* p) { if(!p) return; if(outnet && outnet->udp_wait_first && (p->next_waiting || p == outnet->udp_wait_last) ) { /* delete from waiting list, if it is in the waiting list */ struct pending* prev = NULL, *x = outnet->udp_wait_first; while(x && x != p) { prev = x; x = x->next_waiting; } if(x) { log_assert(x == p); if(prev) prev->next_waiting = p->next_waiting; else outnet->udp_wait_first = p->next_waiting; if(outnet->udp_wait_last == p) outnet->udp_wait_last = prev; } } if(outnet) { (void)rbtree_delete(outnet->pending, p->node.key); } if(p->timer) comm_timer_delete(p->timer); free(p->pkt); free(p); } static void sai6_putrandom(struct sockaddr_in6 *sa, int pfxlen, struct ub_randstate *rnd) { int i, last; if(!(pfxlen > 0 && pfxlen < 128)) return; for(i = 0; i < (128 - pfxlen) / 8; i++) { sa->sin6_addr.s6_addr[15-i] = (uint8_t)ub_random_max(rnd, 256); } last = pfxlen & 7; if(last != 0) { sa->sin6_addr.s6_addr[15-i] |= ((0xFF >> last) & ub_random_max(rnd, 256)); } } /** * Try to open a UDP socket for outgoing communication. * Sets sockets options as needed. * @param addr: socket address. * @param addrlen: length of address. * @param pfxlen: length of network prefix (for address randomisation). * @param port: port override for addr. * @param inuse: if -1 is returned, this bool means the port was in use. * @param rnd: random state (for address randomisation). * @return fd or -1 */ static int udp_sockport(struct sockaddr_storage* addr, socklen_t addrlen, int pfxlen, int port, int* inuse, struct ub_randstate* rnd) { int fd, noproto; if(addr_is_ip6(addr, addrlen)) { int freebind = 0; struct sockaddr_in6 sa = *(struct sockaddr_in6*)addr; sa.sin6_port = (in_port_t)htons((uint16_t)port); if(pfxlen != 0) { freebind = 1; sai6_putrandom(&sa, pfxlen, rnd); } fd = create_udp_sock(AF_INET6, SOCK_DGRAM, (struct sockaddr*)&sa, addrlen, 1, inuse, &noproto, 0, 0, 0, NULL, 0, freebind, 0); } else { struct sockaddr_in* sa = (struct sockaddr_in*)addr; sa->sin_port = (in_port_t)htons((uint16_t)port); fd = create_udp_sock(AF_INET, SOCK_DGRAM, (struct sockaddr*)addr, addrlen, 1, inuse, &noproto, 0, 0, 0, NULL, 0, 0, 0); } return fd; } /** Select random ID */ static int select_id(struct outside_network* outnet, struct pending* pend, sldns_buffer* packet) { int id_tries = 0; pend->id = ((unsigned)ub_random(outnet->rnd)>>8) & 0xffff; LDNS_ID_SET(sldns_buffer_begin(packet), pend->id); /* insert in tree */ pend->node.key = pend; while(!rbtree_insert(outnet->pending, &pend->node)) { /* change ID to avoid collision */ pend->id = ((unsigned)ub_random(outnet->rnd)>>8) & 0xffff; LDNS_ID_SET(sldns_buffer_begin(packet), pend->id); id_tries++; if(id_tries == MAX_ID_RETRY) { pend->id=99999; /* non existant ID */ log_err("failed to generate unique ID, drop msg"); return 0; } } verbose(VERB_ALGO, "inserted new pending reply id=%4.4x", pend->id); return 1; } /** Select random interface and port */ static int select_ifport(struct outside_network* outnet, struct pending* pend, int num_if, struct port_if* ifs) { int my_if, my_port, fd, portno, inuse, tries=0; struct port_if* pif; /* randomly select interface and port */ if(num_if == 0) { verbose(VERB_QUERY, "Need to send query but have no " "outgoing interfaces of that family"); return 0; } log_assert(outnet->unused_fds); tries = 0; while(1) { my_if = ub_random_max(outnet->rnd, num_if); pif = &ifs[my_if]; my_port = ub_random_max(outnet->rnd, pif->avail_total); if(my_port < pif->inuse) { /* port already open */ pend->pc = pif->out[my_port]; verbose(VERB_ALGO, "using UDP if=%d port=%d", my_if, pend->pc->number); break; } /* try to open new port, if fails, loop to try again */ log_assert(pif->inuse < pif->maxout); portno = pif->avail_ports[my_port - pif->inuse]; fd = udp_sockport(&pif->addr, pif->addrlen, pif->pfxlen, portno, &inuse, outnet->rnd); if(fd == -1 && !inuse) { /* nonrecoverable error making socket */ return 0; } if(fd != -1) { verbose(VERB_ALGO, "opened UDP if=%d port=%d", my_if, portno); /* grab fd */ pend->pc = outnet->unused_fds; outnet->unused_fds = pend->pc->next; /* setup portcomm */ pend->pc->next = NULL; pend->pc->number = portno; pend->pc->pif = pif; pend->pc->index = pif->inuse; pend->pc->num_outstanding = 0; comm_point_start_listening(pend->pc->cp, fd, -1); /* grab port in interface */ pif->out[pif->inuse] = pend->pc; pif->avail_ports[my_port - pif->inuse] = pif->avail_ports[pif->avail_total-pif->inuse-1]; pif->inuse++; break; } /* failed, already in use */ verbose(VERB_QUERY, "port %d in use, trying another", portno); tries++; if(tries == MAX_PORT_RETRY) { log_err("failed to find an open port, drop msg"); return 0; } } log_assert(pend->pc); pend->pc->num_outstanding++; return 1; } static int randomize_and_send_udp(struct pending* pend, sldns_buffer* packet, int timeout) { struct timeval tv; struct outside_network* outnet = pend->sq->outnet; /* select id */ if(!select_id(outnet, pend, packet)) { return 0; } /* select src_if, port */ if(addr_is_ip6(&pend->addr, pend->addrlen)) { if(!select_ifport(outnet, pend, outnet->num_ip6, outnet->ip6_ifs)) return 0; } else { if(!select_ifport(outnet, pend, outnet->num_ip4, outnet->ip4_ifs)) return 0; } log_assert(pend->pc && pend->pc->cp); /* send it over the commlink */ if(!comm_point_send_udp_msg(pend->pc->cp, packet, (struct sockaddr*)&pend->addr, pend->addrlen)) { portcomm_loweruse(outnet, pend->pc); return 0; } /* system calls to set timeout after sending UDP to make roundtrip smaller. */ #ifndef S_SPLINT_S tv.tv_sec = timeout/1000; tv.tv_usec = (timeout%1000)*1000; #endif comm_timer_set(pend->timer, &tv); #ifdef USE_DNSTAP if(outnet->dtenv && (outnet->dtenv->log_resolver_query_messages || outnet->dtenv->log_forwarder_query_messages)) dt_msg_send_outside_query(outnet->dtenv, &pend->addr, comm_udp, pend->sq->zone, pend->sq->zonelen, packet); #endif return 1; } struct pending* pending_udp_query(struct serviced_query* sq, struct sldns_buffer* packet, int timeout, comm_point_callback_type* cb, void* cb_arg) { struct pending* pend = (struct pending*)calloc(1, sizeof(*pend)); if(!pend) return NULL; pend->outnet = sq->outnet; pend->sq = sq; pend->addrlen = sq->addrlen; memmove(&pend->addr, &sq->addr, sq->addrlen); pend->cb = cb; pend->cb_arg = cb_arg; pend->node.key = pend; pend->timer = comm_timer_create(sq->outnet->base, pending_udp_timer_cb, pend); if(!pend->timer) { free(pend); return NULL; } if(sq->outnet->unused_fds == NULL) { /* no unused fd, cannot create a new port (randomly) */ verbose(VERB_ALGO, "no fds available, udp query waiting"); pend->timeout = timeout; pend->pkt_len = sldns_buffer_limit(packet); pend->pkt = (uint8_t*)memdup(sldns_buffer_begin(packet), pend->pkt_len); if(!pend->pkt) { comm_timer_delete(pend->timer); free(pend); return NULL; } /* put at end of waiting list */ if(sq->outnet->udp_wait_last) sq->outnet->udp_wait_last->next_waiting = pend; else sq->outnet->udp_wait_first = pend; sq->outnet->udp_wait_last = pend; return pend; } if(!randomize_and_send_udp(pend, packet, timeout)) { pending_delete(sq->outnet, pend); return NULL; } return pend; } void outnet_tcptimer(void* arg) { struct waiting_tcp* w = (struct waiting_tcp*)arg; struct outside_network* outnet = w->outnet; comm_point_callback_type* cb; void* cb_arg; if(w->pkt) { /* it is on the waiting list */ waiting_list_remove(outnet, w); } else { /* it was in use */ struct pending_tcp* pend=(struct pending_tcp*)w->next_waiting; comm_point_close(pend->c); pend->query = NULL; pend->next_free = outnet->tcp_free; outnet->tcp_free = pend; } cb = w->cb; cb_arg = w->cb_arg; waiting_tcp_delete(w); fptr_ok(fptr_whitelist_pending_tcp(cb)); (void)(*cb)(NULL, cb_arg, NETEVENT_TIMEOUT, NULL); use_free_buffer(outnet); } struct waiting_tcp* pending_tcp_query(struct serviced_query* sq, sldns_buffer* packet, int timeout, comm_point_callback_type* callback, void* callback_arg) { struct pending_tcp* pend = sq->outnet->tcp_free; struct waiting_tcp* w; struct timeval tv; uint16_t id; /* if no buffer is free allocate space to store query */ w = (struct waiting_tcp*)malloc(sizeof(struct waiting_tcp) + (pend?0:sldns_buffer_limit(packet))); if(!w) { return NULL; } if(!(w->timer = comm_timer_create(sq->outnet->base, outnet_tcptimer, w))) { free(w); return NULL; } w->pkt = NULL; w->pkt_len = 0; id = ((unsigned)ub_random(sq->outnet->rnd)>>8) & 0xffff; LDNS_ID_SET(sldns_buffer_begin(packet), id); memcpy(&w->addr, &sq->addr, sq->addrlen); w->addrlen = sq->addrlen; w->outnet = sq->outnet; w->cb = callback; w->cb_arg = callback_arg; w->ssl_upstream = sq->ssl_upstream; #ifndef S_SPLINT_S tv.tv_sec = timeout; tv.tv_usec = 0; #endif comm_timer_set(w->timer, &tv); if(pend) { /* we have a buffer available right now */ if(!outnet_tcp_take_into_use(w, sldns_buffer_begin(packet), sldns_buffer_limit(packet))) { waiting_tcp_delete(w); return NULL; } #ifdef USE_DNSTAP if(sq->outnet->dtenv && (sq->outnet->dtenv->log_resolver_query_messages || sq->outnet->dtenv->log_forwarder_query_messages)) dt_msg_send_outside_query(sq->outnet->dtenv, &sq->addr, comm_tcp, sq->zone, sq->zonelen, packet); #endif } else { /* queue up */ w->pkt = (uint8_t*)w + sizeof(struct waiting_tcp); w->pkt_len = sldns_buffer_limit(packet); memmove(w->pkt, sldns_buffer_begin(packet), w->pkt_len); w->next_waiting = NULL; if(sq->outnet->tcp_wait_last) sq->outnet->tcp_wait_last->next_waiting = w; else sq->outnet->tcp_wait_first = w; sq->outnet->tcp_wait_last = w; } return w; } /** create query for serviced queries */ static void serviced_gen_query(sldns_buffer* buff, uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, uint16_t flags) { sldns_buffer_clear(buff); /* skip id */ sldns_buffer_write_u16(buff, flags); sldns_buffer_write_u16(buff, 1); /* qdcount */ sldns_buffer_write_u16(buff, 0); /* ancount */ sldns_buffer_write_u16(buff, 0); /* nscount */ sldns_buffer_write_u16(buff, 0); /* arcount */ sldns_buffer_write(buff, qname, qnamelen); sldns_buffer_write_u16(buff, qtype); sldns_buffer_write_u16(buff, qclass); sldns_buffer_flip(buff); } /** lookup serviced query in serviced query rbtree */ static struct serviced_query* lookup_serviced(struct outside_network* outnet, sldns_buffer* buff, int dnssec, struct sockaddr_storage* addr, socklen_t addrlen, struct edns_option* opt_list) { struct serviced_query key; key.node.key = &key; key.qbuf = sldns_buffer_begin(buff); key.qbuflen = sldns_buffer_limit(buff); key.dnssec = dnssec; memcpy(&key.addr, addr, addrlen); key.addrlen = addrlen; key.outnet = outnet; key.opt_list = opt_list; return (struct serviced_query*)rbtree_search(outnet->serviced, &key); } /** Create new serviced entry */ static struct serviced_query* serviced_create(struct outside_network* outnet, sldns_buffer* buff, int dnssec, int want_dnssec, int nocaps, int tcp_upstream, int ssl_upstream, struct sockaddr_storage* addr, socklen_t addrlen, uint8_t* zone, size_t zonelen, int qtype, struct edns_option* opt_list) { struct serviced_query* sq = (struct serviced_query*)malloc(sizeof(*sq)); #ifdef UNBOUND_DEBUG rbnode_type* ins; #endif if(!sq) return NULL; sq->node.key = sq; sq->qbuf = memdup(sldns_buffer_begin(buff), sldns_buffer_limit(buff)); if(!sq->qbuf) { free(sq); return NULL; } sq->qbuflen = sldns_buffer_limit(buff); sq->zone = memdup(zone, zonelen); if(!sq->zone) { free(sq->qbuf); free(sq); return NULL; } sq->zonelen = zonelen; sq->qtype = qtype; sq->dnssec = dnssec; sq->want_dnssec = want_dnssec; sq->nocaps = nocaps; sq->tcp_upstream = tcp_upstream; sq->ssl_upstream = ssl_upstream; memcpy(&sq->addr, addr, addrlen); sq->addrlen = addrlen; sq->opt_list = NULL; if(opt_list) { sq->opt_list = edns_opt_copy_alloc(opt_list); if(!sq->opt_list) { free(sq->zone); free(sq->qbuf); free(sq); return NULL; } } sq->outnet = outnet; sq->cblist = NULL; sq->pending = NULL; sq->status = serviced_initial; sq->retry = 0; sq->to_be_deleted = 0; #ifdef UNBOUND_DEBUG ins = #else (void) #endif rbtree_insert(outnet->serviced, &sq->node); log_assert(ins != NULL); /* must not be already present */ return sq; } /** remove waiting tcp from the outnet waiting list */ static void waiting_list_remove(struct outside_network* outnet, struct waiting_tcp* w) { struct waiting_tcp* p = outnet->tcp_wait_first, *prev = NULL; while(p) { if(p == w) { /* remove w */ if(prev) prev->next_waiting = w->next_waiting; else outnet->tcp_wait_first = w->next_waiting; if(outnet->tcp_wait_last == w) outnet->tcp_wait_last = prev; return; } prev = p; p = p->next_waiting; } } /** cleanup serviced query entry */ static void serviced_delete(struct serviced_query* sq) { if(sq->pending) { /* clear up the pending query */ if(sq->status == serviced_query_UDP_EDNS || sq->status == serviced_query_UDP || sq->status == serviced_query_PROBE_EDNS || sq->status == serviced_query_UDP_EDNS_FRAG || sq->status == serviced_query_UDP_EDNS_fallback) { struct pending* p = (struct pending*)sq->pending; if(p->pc) portcomm_loweruse(sq->outnet, p->pc); pending_delete(sq->outnet, p); /* this call can cause reentrant calls back into the * mesh */ outnet_send_wait_udp(sq->outnet); } else { struct waiting_tcp* p = (struct waiting_tcp*) sq->pending; if(p->pkt == NULL) { decomission_pending_tcp(sq->outnet, (struct pending_tcp*)p->next_waiting); } else { waiting_list_remove(sq->outnet, p); waiting_tcp_delete(p); } } } /* does not delete from tree, caller has to do that */ serviced_node_del(&sq->node, NULL); } /** perturb a dname capitalization randomly */ static void serviced_perturb_qname(struct ub_randstate* rnd, uint8_t* qbuf, size_t len) { uint8_t lablen; uint8_t* d = qbuf + 10; long int random = 0; int bits = 0; log_assert(len >= 10 + 5 /* offset qname, root, qtype, qclass */); (void)len; lablen = *d++; while(lablen) { while(lablen--) { /* only perturb A-Z, a-z */ if(isalpha((unsigned char)*d)) { /* get a random bit */ if(bits == 0) { random = ub_random(rnd); bits = 30; } if(random & 0x1) { *d = (uint8_t)toupper((unsigned char)*d); } else { *d = (uint8_t)tolower((unsigned char)*d); } random >>= 1; bits--; } d++; } lablen = *d++; } if(verbosity >= VERB_ALGO) { char buf[LDNS_MAX_DOMAINLEN+1]; dname_str(qbuf+10, buf); verbose(VERB_ALGO, "qname perturbed to %s", buf); } } /** put serviced query into a buffer */ static void serviced_encode(struct serviced_query* sq, sldns_buffer* buff, int with_edns) { /* if we are using 0x20 bits for ID randomness, perturb them */ if(sq->outnet->use_caps_for_id && !sq->nocaps) { serviced_perturb_qname(sq->outnet->rnd, sq->qbuf, sq->qbuflen); } /* generate query */ sldns_buffer_clear(buff); sldns_buffer_write_u16(buff, 0); /* id placeholder */ sldns_buffer_write(buff, sq->qbuf, sq->qbuflen); sldns_buffer_flip(buff); if(with_edns) { /* add edns section */ struct edns_data edns; edns.edns_present = 1; edns.ext_rcode = 0; edns.edns_version = EDNS_ADVERTISED_VERSION; edns.opt_list = sq->opt_list; if(sq->status == serviced_query_UDP_EDNS_FRAG) { if(addr_is_ip6(&sq->addr, sq->addrlen)) { if(EDNS_FRAG_SIZE_IP6 < EDNS_ADVERTISED_SIZE) edns.udp_size = EDNS_FRAG_SIZE_IP6; else edns.udp_size = EDNS_ADVERTISED_SIZE; } else { if(EDNS_FRAG_SIZE_IP4 < EDNS_ADVERTISED_SIZE) edns.udp_size = EDNS_FRAG_SIZE_IP4; else edns.udp_size = EDNS_ADVERTISED_SIZE; } } else { edns.udp_size = EDNS_ADVERTISED_SIZE; } edns.bits = 0; if(sq->dnssec & EDNS_DO) edns.bits = EDNS_DO; if(sq->dnssec & BIT_CD) LDNS_CD_SET(sldns_buffer_begin(buff)); attach_edns_record(buff, &edns); } } /** * Perform serviced query UDP sending operation. * Sends UDP with EDNS, unless infra host marked non EDNS. * @param sq: query to send. * @param buff: buffer scratch space. * @return 0 on error. */ static int serviced_udp_send(struct serviced_query* sq, sldns_buffer* buff) { int rtt, vs; uint8_t edns_lame_known; time_t now = *sq->outnet->now_secs; if(!infra_host(sq->outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, now, &vs, &edns_lame_known, &rtt)) return 0; sq->last_rtt = rtt; verbose(VERB_ALGO, "EDNS lookup known=%d vs=%d", edns_lame_known, vs); if(sq->status == serviced_initial) { if(edns_lame_known == 0 && rtt > 5000 && rtt < 10001) { /* perform EDNS lame probe - check if server is * EDNS lame (EDNS queries to it are dropped) */ verbose(VERB_ALGO, "serviced query: send probe to see " " if use of EDNS causes timeouts"); /* even 700 msec may be too small */ rtt = 1000; sq->status = serviced_query_PROBE_EDNS; } else if(vs != -1) { sq->status = serviced_query_UDP_EDNS; } else { sq->status = serviced_query_UDP; } } serviced_encode(sq, buff, (sq->status == serviced_query_UDP_EDNS) || (sq->status == serviced_query_UDP_EDNS_FRAG)); sq->last_sent_time = *sq->outnet->now_tv; sq->edns_lame_known = (int)edns_lame_known; verbose(VERB_ALGO, "serviced query UDP timeout=%d msec", rtt); sq->pending = pending_udp_query(sq, buff, rtt, serviced_udp_callback, sq); if(!sq->pending) return 0; return 1; } /** check that perturbed qname is identical */ static int serviced_check_qname(sldns_buffer* pkt, uint8_t* qbuf, size_t qbuflen) { uint8_t* d1 = sldns_buffer_at(pkt, 12); uint8_t* d2 = qbuf+10; uint8_t len1, len2; int count = 0; log_assert(qbuflen >= 15 /* 10 header, root, type, class */); len1 = *d1++; len2 = *d2++; if(sldns_buffer_limit(pkt) < 12+1+4) /* packet too small for qname */ return 0; while(len1 != 0 || len2 != 0) { if(LABEL_IS_PTR(len1)) { d1 = sldns_buffer_begin(pkt)+PTR_OFFSET(len1, *d1); if(d1 >= sldns_buffer_at(pkt, sldns_buffer_limit(pkt))) return 0; len1 = *d1++; if(count++ > MAX_COMPRESS_PTRS) return 0; continue; } if(d2 > qbuf+qbuflen) return 0; if(len1 != len2) return 0; if(len1 > LDNS_MAX_LABELLEN) return 0; log_assert(len1 <= LDNS_MAX_LABELLEN); log_assert(len2 <= LDNS_MAX_LABELLEN); log_assert(len1 == len2 && len1 != 0); /* compare the labels - bitwise identical */ if(memcmp(d1, d2, len1) != 0) return 0; d1 += len1; d2 += len2; len1 = *d1++; len2 = *d2++; } return 1; } /** call the callbacks for a serviced query */ static void serviced_callbacks(struct serviced_query* sq, int error, struct comm_point* c, struct comm_reply* rep) { struct service_callback* p; int dobackup = (sq->cblist && sq->cblist->next); /* >1 cb*/ uint8_t *backup_p = NULL; size_t backlen = 0; #ifdef UNBOUND_DEBUG rbnode_type* rem = #else (void) #endif /* remove from tree, and schedule for deletion, so that callbacks * can safely deregister themselves and even create new serviced * queries that are identical to this one. */ rbtree_delete(sq->outnet->serviced, sq); log_assert(rem); /* should have been present */ sq->to_be_deleted = 1; verbose(VERB_ALGO, "svcd callbacks start"); if(sq->outnet->use_caps_for_id && error == NETEVENT_NOERROR && c && !sq->nocaps && sq->qtype != LDNS_RR_TYPE_PTR) { /* for type PTR do not check perturbed name in answer, * compatibility with cisco dns guard boxes that mess up * reverse queries 0x20 contents */ /* noerror and nxdomain must have a qname in reply */ if(sldns_buffer_read_u16_at(c->buffer, 4) == 0 && (LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NOERROR || LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NXDOMAIN)) { verbose(VERB_DETAIL, "no qname in reply to check 0x20ID"); log_addr(VERB_DETAIL, "from server", &sq->addr, sq->addrlen); log_buf(VERB_DETAIL, "for packet", c->buffer); error = NETEVENT_CLOSED; c = NULL; } else if(sldns_buffer_read_u16_at(c->buffer, 4) > 0 && !serviced_check_qname(c->buffer, sq->qbuf, sq->qbuflen)) { verbose(VERB_DETAIL, "wrong 0x20-ID in reply qname"); log_addr(VERB_DETAIL, "from server", &sq->addr, sq->addrlen); log_buf(VERB_DETAIL, "for packet", c->buffer); error = NETEVENT_CAPSFAIL; /* and cleanup too */ pkt_dname_tolower(c->buffer, sldns_buffer_at(c->buffer, 12)); } else { verbose(VERB_ALGO, "good 0x20-ID in reply qname"); /* cleanup caps, prettier cache contents. */ pkt_dname_tolower(c->buffer, sldns_buffer_at(c->buffer, 12)); } } if(dobackup && c) { /* make a backup of the query, since the querystate processing * may send outgoing queries that overwrite the buffer. * use secondary buffer to store the query. * This is a data copy, but faster than packet to server */ backlen = sldns_buffer_limit(c->buffer); backup_p = memdup(sldns_buffer_begin(c->buffer), backlen); if(!backup_p) { log_err("malloc failure in serviced query callbacks"); error = NETEVENT_CLOSED; c = NULL; } sq->outnet->svcd_overhead = backlen; } /* test the actual sq->cblist, because the next elem could be deleted*/ while((p=sq->cblist) != NULL) { sq->cblist = p->next; /* remove this element */ if(dobackup && c) { sldns_buffer_clear(c->buffer); sldns_buffer_write(c->buffer, backup_p, backlen); sldns_buffer_flip(c->buffer); } fptr_ok(fptr_whitelist_serviced_query(p->cb)); (void)(*p->cb)(c, p->cb_arg, error, rep); free(p); } if(backup_p) { free(backup_p); sq->outnet->svcd_overhead = 0; } verbose(VERB_ALGO, "svcd callbacks end"); log_assert(sq->cblist == NULL); serviced_delete(sq); } int serviced_tcp_callback(struct comm_point* c, void* arg, int error, struct comm_reply* rep) { struct serviced_query* sq = (struct serviced_query*)arg; struct comm_reply r2; sq->pending = NULL; /* removed after this callback */ if(error != NETEVENT_NOERROR) log_addr(VERB_QUERY, "tcp error for address", &sq->addr, sq->addrlen); if(error==NETEVENT_NOERROR) infra_update_tcp_works(sq->outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen); #ifdef USE_DNSTAP if(error==NETEVENT_NOERROR && sq->outnet->dtenv && (sq->outnet->dtenv->log_resolver_response_messages || sq->outnet->dtenv->log_forwarder_response_messages)) dt_msg_send_outside_response(sq->outnet->dtenv, &sq->addr, c->type, sq->zone, sq->zonelen, sq->qbuf, sq->qbuflen, &sq->last_sent_time, sq->outnet->now_tv, c->buffer); #endif if(error==NETEVENT_NOERROR && sq->status == serviced_query_TCP_EDNS && (LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == LDNS_RCODE_FORMERR || LDNS_RCODE_WIRE(sldns_buffer_begin( c->buffer)) == LDNS_RCODE_NOTIMPL) ) { /* attempt to fallback to nonEDNS */ sq->status = serviced_query_TCP_EDNS_fallback; serviced_tcp_initiate(sq, c->buffer); return 0; } else if(error==NETEVENT_NOERROR && sq->status == serviced_query_TCP_EDNS_fallback && (LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NOERROR || LDNS_RCODE_WIRE( sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NXDOMAIN || LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == LDNS_RCODE_YXDOMAIN)) { /* the fallback produced a result that looks promising, note * that this server should be approached without EDNS */ /* only store noEDNS in cache if domain is noDNSSEC */ if(!sq->want_dnssec) if(!infra_edns_update(sq->outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, -1, *sq->outnet->now_secs)) log_err("Out of memory caching no edns for host"); sq->status = serviced_query_TCP; } if(sq->tcp_upstream || sq->ssl_upstream) { struct timeval now = *sq->outnet->now_tv; if(now.tv_sec > sq->last_sent_time.tv_sec || (now.tv_sec == sq->last_sent_time.tv_sec && now.tv_usec > sq->last_sent_time.tv_usec)) { /* convert from microseconds to milliseconds */ int roundtime = ((int)(now.tv_sec - sq->last_sent_time.tv_sec))*1000 + ((int)now.tv_usec - (int)sq->last_sent_time.tv_usec)/1000; verbose(VERB_ALGO, "measured TCP-time at %d msec", roundtime); log_assert(roundtime >= 0); /* only store if less then AUTH_TIMEOUT seconds, it could be * huge due to system-hibernated and we woke up */ if(roundtime < TCP_AUTH_QUERY_TIMEOUT*1000) { if(!infra_rtt_update(sq->outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, sq->qtype, roundtime, sq->last_rtt, (time_t)now.tv_sec)) log_err("out of memory noting rtt."); } } } /* insert address into reply info */ if(!rep) { /* create one if there isn't (on errors) */ rep = &r2; r2.c = c; } memcpy(&rep->addr, &sq->addr, sq->addrlen); rep->addrlen = sq->addrlen; serviced_callbacks(sq, error, c, rep); return 0; } static void serviced_tcp_initiate(struct serviced_query* sq, sldns_buffer* buff) { verbose(VERB_ALGO, "initiate TCP query %s", sq->status==serviced_query_TCP_EDNS?"EDNS":""); serviced_encode(sq, buff, sq->status == serviced_query_TCP_EDNS); sq->last_sent_time = *sq->outnet->now_tv; sq->pending = pending_tcp_query(sq, buff, TCP_AUTH_QUERY_TIMEOUT, serviced_tcp_callback, sq); if(!sq->pending) { /* delete from tree so that a retry by above layer does not * clash with this entry */ log_err("serviced_tcp_initiate: failed to send tcp query"); serviced_callbacks(sq, NETEVENT_CLOSED, NULL, NULL); } } /** Send serviced query over TCP return false on initial failure */ static int serviced_tcp_send(struct serviced_query* sq, sldns_buffer* buff) { int vs, rtt; uint8_t edns_lame_known; if(!infra_host(sq->outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, *sq->outnet->now_secs, &vs, &edns_lame_known, &rtt)) return 0; if(vs != -1) sq->status = serviced_query_TCP_EDNS; else sq->status = serviced_query_TCP; serviced_encode(sq, buff, sq->status == serviced_query_TCP_EDNS); sq->last_sent_time = *sq->outnet->now_tv; sq->pending = pending_tcp_query(sq, buff, TCP_AUTH_QUERY_TIMEOUT, serviced_tcp_callback, sq); return sq->pending != NULL; } /* see if packet is edns malformed; got zeroes at start. * This is from servers that return malformed packets to EDNS0 queries, * but they return good packets for nonEDNS0 queries. * We try to detect their output; without resorting to a full parse or * check for too many bytes after the end of the packet. */ static int packet_edns_malformed(struct sldns_buffer* buf, int qtype) { size_t len; if(sldns_buffer_limit(buf) < LDNS_HEADER_SIZE) return 1; /* malformed */ /* they have NOERROR rcode, 1 answer. */ if(LDNS_RCODE_WIRE(sldns_buffer_begin(buf)) != LDNS_RCODE_NOERROR) return 0; /* one query (to skip) and answer records */ if(LDNS_QDCOUNT(sldns_buffer_begin(buf)) != 1 || LDNS_ANCOUNT(sldns_buffer_begin(buf)) == 0) return 0; /* skip qname */ len = dname_valid(sldns_buffer_at(buf, LDNS_HEADER_SIZE), sldns_buffer_limit(buf)-LDNS_HEADER_SIZE); if(len == 0) return 0; if(len == 1 && qtype == 0) return 0; /* we asked for '.' and type 0 */ /* and then 4 bytes (type and class of query) */ if(sldns_buffer_limit(buf) < LDNS_HEADER_SIZE + len + 4 + 3) return 0; /* and start with 11 zeroes as the answer RR */ /* so check the qtype of the answer record, qname=0, type=0 */ if(sldns_buffer_at(buf, LDNS_HEADER_SIZE+len+4)[0] == 0 && sldns_buffer_at(buf, LDNS_HEADER_SIZE+len+4)[1] == 0 && sldns_buffer_at(buf, LDNS_HEADER_SIZE+len+4)[2] == 0) return 1; return 0; } int serviced_udp_callback(struct comm_point* c, void* arg, int error, struct comm_reply* rep) { struct serviced_query* sq = (struct serviced_query*)arg; struct outside_network* outnet = sq->outnet; struct timeval now = *sq->outnet->now_tv; int fallback_tcp = 0; sq->pending = NULL; /* removed after callback */ if(error == NETEVENT_TIMEOUT) { int rto = 0; if(sq->status == serviced_query_PROBE_EDNS) { /* non-EDNS probe failed; we do not know its status, * keep trying with EDNS, timeout may not be caused * by EDNS. */ sq->status = serviced_query_UDP_EDNS; } if(sq->status == serviced_query_UDP_EDNS && sq->last_rtt < 5000) { /* fallback to 1480/1280 */ sq->status = serviced_query_UDP_EDNS_FRAG; log_name_addr(VERB_ALGO, "try edns1xx0", sq->qbuf+10, &sq->addr, sq->addrlen); if(!serviced_udp_send(sq, c->buffer)) { serviced_callbacks(sq, NETEVENT_CLOSED, c, rep); } return 0; } if(sq->status == serviced_query_UDP_EDNS_FRAG) { /* fragmentation size did not fix it */ sq->status = serviced_query_UDP_EDNS; } sq->retry++; if(!(rto=infra_rtt_update(outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, sq->qtype, -1, sq->last_rtt, (time_t)now.tv_sec))) log_err("out of memory in UDP exponential backoff"); if(sq->retry < OUTBOUND_UDP_RETRY) { log_name_addr(VERB_ALGO, "retry query", sq->qbuf+10, &sq->addr, sq->addrlen); if(!serviced_udp_send(sq, c->buffer)) { serviced_callbacks(sq, NETEVENT_CLOSED, c, rep); } return 0; } if(rto >= RTT_MAX_TIMEOUT) { fallback_tcp = 1; /* UDP does not work, fallback to TCP below */ } else { serviced_callbacks(sq, NETEVENT_TIMEOUT, c, rep); return 0; } } else if(error != NETEVENT_NOERROR) { /* udp returns error (due to no ID or interface available) */ serviced_callbacks(sq, error, c, rep); return 0; } #ifdef USE_DNSTAP if(error == NETEVENT_NOERROR && outnet->dtenv && (outnet->dtenv->log_resolver_response_messages || outnet->dtenv->log_forwarder_response_messages)) dt_msg_send_outside_response(outnet->dtenv, &sq->addr, c->type, sq->zone, sq->zonelen, sq->qbuf, sq->qbuflen, &sq->last_sent_time, sq->outnet->now_tv, c->buffer); #endif if(!fallback_tcp) { if( (sq->status == serviced_query_UDP_EDNS ||sq->status == serviced_query_UDP_EDNS_FRAG) && (LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == LDNS_RCODE_FORMERR || LDNS_RCODE_WIRE( sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NOTIMPL || packet_edns_malformed(c->buffer, sq->qtype) )) { /* try to get an answer by falling back without EDNS */ verbose(VERB_ALGO, "serviced query: attempt without EDNS"); sq->status = serviced_query_UDP_EDNS_fallback; sq->retry = 0; if(!serviced_udp_send(sq, c->buffer)) { serviced_callbacks(sq, NETEVENT_CLOSED, c, rep); } return 0; } else if(sq->status == serviced_query_PROBE_EDNS) { /* probe without EDNS succeeds, so we conclude that this * host likely has EDNS packets dropped */ log_addr(VERB_DETAIL, "timeouts, concluded that connection to " "host drops EDNS packets", &sq->addr, sq->addrlen); /* only store noEDNS in cache if domain is noDNSSEC */ if(!sq->want_dnssec) if(!infra_edns_update(outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, -1, (time_t)now.tv_sec)) { log_err("Out of memory caching no edns for host"); } sq->status = serviced_query_UDP; } else if(sq->status == serviced_query_UDP_EDNS && !sq->edns_lame_known) { /* now we know that edns queries received answers store that */ log_addr(VERB_ALGO, "serviced query: EDNS works for", &sq->addr, sq->addrlen); if(!infra_edns_update(outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, 0, (time_t)now.tv_sec)) { log_err("Out of memory caching edns works"); } sq->edns_lame_known = 1; } else if(sq->status == serviced_query_UDP_EDNS_fallback && !sq->edns_lame_known && (LDNS_RCODE_WIRE( sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NOERROR || LDNS_RCODE_WIRE(sldns_buffer_begin(c->buffer)) == LDNS_RCODE_NXDOMAIN || LDNS_RCODE_WIRE(sldns_buffer_begin( c->buffer)) == LDNS_RCODE_YXDOMAIN)) { /* the fallback produced a result that looks promising, note * that this server should be approached without EDNS */ /* only store noEDNS in cache if domain is noDNSSEC */ if(!sq->want_dnssec) { log_addr(VERB_ALGO, "serviced query: EDNS fails for", &sq->addr, sq->addrlen); if(!infra_edns_update(outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, -1, (time_t)now.tv_sec)) { log_err("Out of memory caching no edns for host"); } } else { log_addr(VERB_ALGO, "serviced query: EDNS fails, but " "not stored because need DNSSEC for", &sq->addr, sq->addrlen); } sq->status = serviced_query_UDP; } if(now.tv_sec > sq->last_sent_time.tv_sec || (now.tv_sec == sq->last_sent_time.tv_sec && now.tv_usec > sq->last_sent_time.tv_usec)) { /* convert from microseconds to milliseconds */ int roundtime = ((int)(now.tv_sec - sq->last_sent_time.tv_sec))*1000 + ((int)now.tv_usec - (int)sq->last_sent_time.tv_usec)/1000; verbose(VERB_ALGO, "measured roundtrip at %d msec", roundtime); log_assert(roundtime >= 0); /* in case the system hibernated, do not enter a huge value, * above this value gives trouble with server selection */ if(roundtime < 60000) { if(!infra_rtt_update(outnet->infra, &sq->addr, sq->addrlen, sq->zone, sq->zonelen, sq->qtype, roundtime, sq->last_rtt, (time_t)now.tv_sec)) log_err("out of memory noting rtt."); } } } /* end of if_!fallback_tcp */ /* perform TC flag check and TCP fallback after updating our * cache entries for EDNS status and RTT times */ if(LDNS_TC_WIRE(sldns_buffer_begin(c->buffer)) || fallback_tcp) { /* fallback to TCP */ /* this discards partial UDP contents */ if(sq->status == serviced_query_UDP_EDNS || sq->status == serviced_query_UDP_EDNS_FRAG || sq->status == serviced_query_UDP_EDNS_fallback) /* if we have unfinished EDNS_fallback, start again */ sq->status = serviced_query_TCP_EDNS; else sq->status = serviced_query_TCP; serviced_tcp_initiate(sq, c->buffer); return 0; } /* yay! an answer */ serviced_callbacks(sq, error, c, rep); return 0; } struct serviced_query* outnet_serviced_query(struct outside_network* outnet, struct query_info* qinfo, uint16_t flags, int dnssec, int want_dnssec, int nocaps, int tcp_upstream, int ssl_upstream, struct sockaddr_storage* addr, socklen_t addrlen, uint8_t* zone, size_t zonelen, struct module_qstate* qstate, comm_point_callback_type* callback, void* callback_arg, sldns_buffer* buff, struct module_env* env) { struct serviced_query* sq; struct service_callback* cb; if(!inplace_cb_query_call(env, qinfo, flags, addr, addrlen, zone, zonelen, qstate, qstate->region)) return NULL; serviced_gen_query(buff, qinfo->qname, qinfo->qname_len, qinfo->qtype, qinfo->qclass, flags); sq = lookup_serviced(outnet, buff, dnssec, addr, addrlen, qstate->edns_opts_back_out); /* duplicate entries are included in the callback list, because * there is a counterpart registration by our caller that needs to * be doubly-removed (with callbacks perhaps). */ if(!(cb = (struct service_callback*)malloc(sizeof(*cb)))) return NULL; if(!sq) { /* make new serviced query entry */ sq = serviced_create(outnet, buff, dnssec, want_dnssec, nocaps, tcp_upstream, ssl_upstream, addr, addrlen, zone, zonelen, (int)qinfo->qtype, qstate->edns_opts_back_out); if(!sq) { free(cb); return NULL; } /* perform first network action */ if(outnet->do_udp && !(tcp_upstream || ssl_upstream)) { if(!serviced_udp_send(sq, buff)) { (void)rbtree_delete(outnet->serviced, sq); free(sq->qbuf); free(sq->zone); free(sq); free(cb); return NULL; } } else { if(!serviced_tcp_send(sq, buff)) { (void)rbtree_delete(outnet->serviced, sq); free(sq->qbuf); free(sq->zone); free(sq); free(cb); return NULL; } } } /* add callback to list of callbacks */ cb->cb = callback; cb->cb_arg = callback_arg; cb->next = sq->cblist; sq->cblist = cb; return sq; } /** remove callback from list */ static void callback_list_remove(struct serviced_query* sq, void* cb_arg) { struct service_callback** pp = &sq->cblist; while(*pp) { if((*pp)->cb_arg == cb_arg) { struct service_callback* del = *pp; *pp = del->next; free(del); return; } pp = &(*pp)->next; } } void outnet_serviced_query_stop(struct serviced_query* sq, void* cb_arg) { if(!sq) return; callback_list_remove(sq, cb_arg); /* if callbacks() routine scheduled deletion, let it do that */ if(!sq->cblist && !sq->to_be_deleted) { (void)rbtree_delete(sq->outnet->serviced, sq); serviced_delete(sq); } } /** get memory used by waiting tcp entry (in use or not) */ static size_t waiting_tcp_get_mem(struct waiting_tcp* w) { size_t s; if(!w) return 0; s = sizeof(*w) + w->pkt_len; if(w->timer) s += comm_timer_get_mem(w->timer); return s; } /** get memory used by port if */ static size_t if_get_mem(struct port_if* pif) { size_t s; int i; s = sizeof(*pif) + sizeof(int)*pif->avail_total + sizeof(struct port_comm*)*pif->maxout; for(i=0; iinuse; i++) s += sizeof(*pif->out[i]) + comm_point_get_mem(pif->out[i]->cp); return s; } /** get memory used by waiting udp */ static size_t waiting_udp_get_mem(struct pending* w) { size_t s; s = sizeof(*w) + comm_timer_get_mem(w->timer) + w->pkt_len; return s; } size_t outnet_get_mem(struct outside_network* outnet) { size_t i; int k; struct waiting_tcp* w; struct pending* u; struct serviced_query* sq; struct service_callback* sb; struct port_comm* pc; size_t s = sizeof(*outnet) + sizeof(*outnet->base) + sizeof(*outnet->udp_buff) + sldns_buffer_capacity(outnet->udp_buff); /* second buffer is not ours */ for(pc = outnet->unused_fds; pc; pc = pc->next) { s += sizeof(*pc) + comm_point_get_mem(pc->cp); } for(k=0; knum_ip4; k++) s += if_get_mem(&outnet->ip4_ifs[k]); for(k=0; knum_ip6; k++) s += if_get_mem(&outnet->ip6_ifs[k]); for(u=outnet->udp_wait_first; u; u=u->next_waiting) s += waiting_udp_get_mem(u); s += sizeof(struct pending_tcp*)*outnet->num_tcp; for(i=0; inum_tcp; i++) { s += sizeof(struct pending_tcp); s += comm_point_get_mem(outnet->tcp_conns[i]->c); if(outnet->tcp_conns[i]->query) s += waiting_tcp_get_mem(outnet->tcp_conns[i]->query); } for(w=outnet->tcp_wait_first; w; w = w->next_waiting) s += waiting_tcp_get_mem(w); s += sizeof(*outnet->pending); s += (sizeof(struct pending) + comm_timer_get_mem(NULL)) * outnet->pending->count; s += sizeof(*outnet->serviced); s += outnet->svcd_overhead; RBTREE_FOR(sq, struct serviced_query*, outnet->serviced) { s += sizeof(*sq) + sq->qbuflen; for(sb = sq->cblist; sb; sb = sb->next) s += sizeof(*sb); } return s; } size_t serviced_get_mem(struct serviced_query* sq) { struct service_callback* sb; size_t s; s = sizeof(*sq) + sq->qbuflen; for(sb = sq->cblist; sb; sb = sb->next) s += sizeof(*sb); if(sq->status == serviced_query_UDP_EDNS || sq->status == serviced_query_UDP || sq->status == serviced_query_PROBE_EDNS || sq->status == serviced_query_UDP_EDNS_FRAG || sq->status == serviced_query_UDP_EDNS_fallback) { s += sizeof(struct pending); s += comm_timer_get_mem(NULL); } else { /* does not have size of the pkt pointer */ /* always has a timer except on malloc failures */ /* these sizes are part of the main outside network mem */ /* s += sizeof(struct waiting_tcp); s += comm_timer_get_mem(NULL); */ } return s; }