/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright 2014 Nexenta Systems, Inc. All rights reserved. */ /* * DNS query helper functions for addisc.c */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "adutils_impl.h" #include "addisc_impl.h" static void save_addr(ad_disc_cds_t *, sa_family_t, uchar_t *, size_t); static struct addrinfo *make_addrinfo(sa_family_t, uchar_t *, size_t); static void do_getaddrinfo(ad_disc_cds_t *); static ad_disc_cds_t *srv_parse(uchar_t *, int, int *, int *); static void add_preferred(ad_disc_cds_t *, ad_disc_ds_t *, int *, int); static void get_addresses(ad_disc_cds_t *, int); /* * Simplified version of srv_query() for domain auto-discovery. */ int srv_getdom(res_state state, const char *svc_name, char **rrname) { union { HEADER hdr; uchar_t buf[NS_MAXMSG]; } msg; int len, qdcount, ancount; uchar_t *ptr, *eom; char namebuf[NS_MAXDNAME]; /* query necessary resource records */ *rrname = NULL; if (DBG(DNS, 1)) { logger(LOG_DEBUG, "Looking for SRV RRs '%s.*'", svc_name); } len = res_nsearch(state, svc_name, C_IN, T_SRV, msg.buf, sizeof (msg.buf)); if (len < 0) { if (DBG(DNS, 0)) { logger(LOG_DEBUG, "DNS search for '%s' failed (%s)", svc_name, hstrerror(state->res_h_errno)); } return (-1); } if (len > sizeof (msg.buf)) { logger(LOG_WARNING, "DNS query %ib message doesn't fit into %ib buffer", len, sizeof (msg.buf)); len = sizeof (msg.buf); } /* parse the reply header */ ptr = msg.buf + sizeof (msg.hdr); eom = msg.buf + len; qdcount = ntohs(msg.hdr.qdcount); ancount = ntohs(msg.hdr.ancount); /* skip the question section */ len = ns_skiprr(ptr, eom, ns_s_qd, qdcount); if (len < 0) { logger(LOG_ERR, "DNS query invalid message format"); return (-1); } ptr += len; /* parse the answer section */ if (ancount < 1) { logger(LOG_ERR, "DNS query - no answers"); return (-1); } len = dn_expand(msg.buf, eom, ptr, namebuf, sizeof (namebuf)); if (len < 0) { logger(LOG_ERR, "DNS query invalid message format"); return (-1); } *rrname = strdup(namebuf); if (*rrname == NULL) { logger(LOG_ERR, "Out of memory"); return (-1); } return (0); } /* * Compare SRC RRs; used with qsort(). Sort order: * "Earliest" (lowest number) priority first, * then weight highest to lowest. */ static int srvcmp(ad_disc_ds_t *s1, ad_disc_ds_t *s2) { if (s1->priority < s2->priority) return (-1); else if (s1->priority > s2->priority) return (1); if (s1->weight < s2->weight) return (1); else if (s1->weight > s2->weight) return (-1); return (0); } /* * Query or search the SRV RRs for a given name. * * If dname == NULL then search (as in res_nsearch(3RESOLV), honoring any * search list/option), else query (as in res_nquery(3RESOLV)). * * The output TTL will be the one of the SRV RR with the lowest TTL. */ ad_disc_cds_t * srv_query(res_state state, const char *svc_name, const char *dname, ad_disc_ds_t *prefer) { ad_disc_cds_t *cds_res = NULL; uchar_t *msg = NULL; int len, scnt, maxcnt; msg = malloc(NS_MAXMSG); if (msg == NULL) { logger(LOG_ERR, "Out of memory"); return (NULL); } /* query necessary resource records */ /* Search, querydomain or query */ if (dname == NULL) { dname = "*"; if (DBG(DNS, 1)) { logger(LOG_DEBUG, "Looking for SRV RRs '%s.*'", svc_name); } len = res_nsearch(state, svc_name, C_IN, T_SRV, msg, NS_MAXMSG); if (len < 0) { if (DBG(DNS, 0)) { logger(LOG_DEBUG, "DNS search for '%s' failed (%s)", svc_name, hstrerror(state->res_h_errno)); } goto errout; } } else { /* dname != NULL */ if (DBG(DNS, 1)) { logger(LOG_DEBUG, "Looking for SRV RRs '%s.%s' ", svc_name, dname); } len = res_nquerydomain(state, svc_name, dname, C_IN, T_SRV, msg, NS_MAXMSG); if (len < 0) { if (DBG(DNS, 0)) { logger(LOG_DEBUG, "DNS: %s.%s: %s", svc_name, dname, hstrerror(state->res_h_errno)); } goto errout; } } if (len > NS_MAXMSG) { logger(LOG_WARNING, "DNS query %ib message doesn't fit into %ib buffer", len, NS_MAXMSG); len = NS_MAXMSG; } /* parse the reply header */ cds_res = srv_parse(msg, len, &scnt, &maxcnt); if (cds_res == NULL) goto errout; if (prefer != NULL) add_preferred(cds_res, prefer, &scnt, maxcnt); get_addresses(cds_res, scnt); /* sort list of candidates */ if (scnt > 1) qsort(cds_res, scnt, sizeof (*cds_res), (int (*)(const void *, const void *))srvcmp); free(msg); return (cds_res); errout: free(msg); return (NULL); } static ad_disc_cds_t * srv_parse(uchar_t *msg, int len, int *scnt, int *maxcnt) { ad_disc_cds_t *cds; ad_disc_cds_t *cds_res = NULL; HEADER *hdr; int i, qdcount, ancount, nscount, arcount; uchar_t *ptr, *eom; uchar_t *end; uint16_t type; /* LINTED E_FUNC_SET_NOT_USED */ uint16_t class __unused; uint32_t rttl; uint16_t size; char namebuf[NS_MAXDNAME]; eom = msg + len; hdr = (void *)msg; ptr = msg + sizeof (HEADER); qdcount = ntohs(hdr->qdcount); ancount = ntohs(hdr->ancount); nscount = ntohs(hdr->nscount); arcount = ntohs(hdr->arcount); /* skip the question section */ len = ns_skiprr(ptr, eom, ns_s_qd, qdcount); if (len < 0) { logger(LOG_ERR, "DNS query invalid message format"); return (NULL); } ptr += len; /* * Walk through the answer section, building the result array. * The array size is +2 because we (possibly) add the preferred * DC if it was not there, and an empty one (null termination). */ *maxcnt = ancount + 2; cds_res = calloc(*maxcnt, sizeof (*cds_res)); if (cds_res == NULL) { logger(LOG_ERR, "Out of memory"); return (NULL); } cds = cds_res; for (i = 0; i < ancount; i++) { len = dn_expand(msg, eom, ptr, namebuf, sizeof (namebuf)); if (len < 0) { logger(LOG_ERR, "DNS query invalid message format"); goto err; } ptr += len; NS_GET16(type, ptr); NS_GET16(class, ptr); NS_GET32(rttl, ptr); NS_GET16(size, ptr); if ((end = ptr + size) > eom) { logger(LOG_ERR, "DNS query invalid message format"); goto err; } if (type != T_SRV) { ptr = end; continue; } NS_GET16(cds->cds_ds.priority, ptr); NS_GET16(cds->cds_ds.weight, ptr); NS_GET16(cds->cds_ds.port, ptr); len = dn_expand(msg, eom, ptr, cds->cds_ds.host, sizeof (cds->cds_ds.host)); if (len < 0) { logger(LOG_ERR, "DNS query invalid SRV record"); goto err; } cds->cds_ds.ttl = rttl; if (DBG(DNS, 2)) { logger(LOG_DEBUG, " %s", namebuf); logger(LOG_DEBUG, " ttl=%d pri=%d weight=%d %s:%d", rttl, cds->cds_ds.priority, cds->cds_ds.weight, cds->cds_ds.host, cds->cds_ds.port); } cds++; /* move ptr to the end of current record */ ptr = end; } *scnt = (cds - cds_res); /* skip the nameservers section (if any) */ len = ns_skiprr(ptr, eom, ns_s_ns, nscount); if (len < 0) { logger(LOG_ERR, "DNS query invalid message format"); goto err; } ptr += len; /* walk through the additional records */ for (i = 0; i < arcount; i++) { sa_family_t af; len = dn_expand(msg, eom, ptr, namebuf, sizeof (namebuf)); if (len < 0) { logger(LOG_ERR, "DNS query invalid message format"); goto err; } ptr += len; NS_GET16(type, ptr); NS_GET16(class, ptr); NS_GET32(rttl, ptr); NS_GET16(size, ptr); if ((end = ptr + size) > eom) { logger(LOG_ERR, "DNS query invalid message format"); goto err; } switch (type) { case ns_t_a: af = AF_INET; break; case ns_t_aaaa: af = AF_INET6; break; default: continue; } if (DBG(DNS, 2)) { char abuf[INET6_ADDRSTRLEN]; const char *ap; ap = inet_ntop(af, ptr, abuf, sizeof (abuf)); logger(LOG_DEBUG, " %s %s %s", (af == AF_INET) ? "A " : "AAAA", (ap) ? ap : "?", namebuf); } /* Find the server, add to its address list. */ for (cds = cds_res; cds->cds_ds.host[0] != '\0'; cds++) if (0 == strcmp(namebuf, cds->cds_ds.host)) save_addr(cds, af, ptr, size); /* move ptr to the end of current record */ ptr = end; } return (cds_res); err: free(cds_res); return (NULL); } /* * Save this address on the server, if not already there. */ static void save_addr(ad_disc_cds_t *cds, sa_family_t af, uchar_t *addr, size_t alen) { struct addrinfo *ai, *new_ai, *last_ai; new_ai = make_addrinfo(af, addr, alen); if (new_ai == NULL) return; last_ai = NULL; for (ai = cds->cds_ai; ai != NULL; ai = ai->ai_next) { last_ai = ai; if (new_ai->ai_family == ai->ai_family && new_ai->ai_addrlen == ai->ai_addrlen && 0 == memcmp(new_ai->ai_addr, ai->ai_addr, ai->ai_addrlen)) { /* it's already there */ freeaddrinfo(new_ai); return; } } /* Not found. Append. */ if (last_ai != NULL) { last_ai->ai_next = new_ai; } else { cds->cds_ai = new_ai; } } static struct addrinfo * make_addrinfo(sa_family_t af, uchar_t *addr, size_t alen) { struct addrinfo *ai; struct sockaddr *sa; struct sockaddr_in *sin; struct sockaddr_in6 *sin6; int slen; ai = calloc(1, sizeof (*ai)); sa = calloc(1, sizeof (struct sockaddr_in6)); if (ai == NULL || sa == NULL) { logger(LOG_ERR, "Out of memory"); goto errout; } switch (af) { case AF_INET: sin = (void *)sa; if (alen < sizeof (in_addr_t)) { logger(LOG_ERR, "bad IPv4 addr len"); goto errout; } alen = sizeof (in_addr_t); sin->sin_family = af; (void) memcpy(&sin->sin_addr, addr, alen); slen = sizeof (*sin); break; case AF_INET6: sin6 = (void *)sa; if (alen < sizeof (in6_addr_t)) { logger(LOG_ERR, "bad IPv6 addr len"); goto errout; } alen = sizeof (in6_addr_t); sin6->sin6_family = af; (void) memcpy(&sin6->sin6_addr, addr, alen); slen = sizeof (*sin6); break; default: goto errout; } ai->ai_family = af; ai->ai_addrlen = slen; ai->ai_addr = sa; sa->sa_family = af; return (ai); errout: free(ai); free(sa); return (NULL); } /* * Set a preferred candidate, which may already be in the list, * in which case we just bump its priority, or else add it. */ static void add_preferred(ad_disc_cds_t *cds, ad_disc_ds_t *prefer, int *nds, int maxds) { ad_disc_ds_t *ds; int i; assert(*nds < maxds); for (i = 0; i < *nds; i++) { ds = &cds[i].cds_ds; if (strcasecmp(ds->host, prefer->host) == 0) { /* Force this element to be sorted first. */ ds->priority = 0; ds->weight = 200; return; } } /* * The preferred DC was not found in this DNS response, * so add it. Again arrange for it to be sorted first. * Address info. is added later. */ ds = &cds[i].cds_ds; (void) memcpy(ds, prefer, sizeof (*ds)); ds->priority = 0; ds->weight = 200; *nds = i + 1; } /* * Do another pass over the array to check for missing addresses and * try resolving the names. Normally, the DNS response from AD will * have supplied additional address records for all the SRV records. */ static void get_addresses(ad_disc_cds_t *cds, int cnt) { int i; for (i = 0; i < cnt; i++) { if (cds[i].cds_ai == NULL) { do_getaddrinfo(&cds[i]); } } } static void do_getaddrinfo(ad_disc_cds_t *cds) { struct addrinfo hints; struct addrinfo *ai; ad_disc_ds_t *ds; time_t t0, t1; int err; (void) memset(&hints, 0, sizeof (hints)); hints.ai_protocol = IPPROTO_TCP; hints.ai_socktype = SOCK_STREAM; ds = &cds->cds_ds; /* * This getaddrinfo call may take a LONG time, i.e. if our * DNS servers are misconfigured or not responding. * We need something like getaddrinfo_a(), with a timeout. * For now, just log when this happens so we'll know * if these calls are taking a long time. */ if (DBG(DNS, 2)) logger(LOG_DEBUG, "getaddrinfo %s ...", ds->host); t0 = time(NULL); err = getaddrinfo(cds->cds_ds.host, NULL, &hints, &ai); t1 = time(NULL); if (DBG(DNS, 2)) logger(LOG_DEBUG, "getaddrinfo %s rc=%d", ds->host, err); if (t1 > (t0 + 5)) { logger(LOG_WARNING, "Lookup host (%s) took %u sec. " "(Check DNS settings)", ds->host, (int)(t1 - t0)); } if (err != 0) { logger(LOG_ERR, "No address for host: %s (%s)", ds->host, gai_strerror(err)); /* Make this sort at the end. */ ds->priority = 1 << 16; return; } cds->cds_ai = ai; } void srv_free(ad_disc_cds_t *cds_vec) { ad_disc_cds_t *cds; for (cds = cds_vec; cds->cds_ds.host[0] != '\0'; cds++) { if (cds->cds_ai != NULL) { freeaddrinfo(cds->cds_ai); } } free(cds_vec); }