Adding upstream version 1:9.16.44.upstream/1%9.16.44upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1365 insertions, 0 deletions

diff --git a/lib/irs/getaddrinfo.c b/lib/irs/getaddrinfo.c
new file mode 100644
index 0000000..f450a55
--- /dev/null
+++ b/lib/irs/getaddrinfo.c
@@ -0,0 +1,1365 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0.  If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+/**
+ *    getaddrinfo() is used to get a list of IP addresses and port
+ *    numbers for host hostname and service servname as defined in RFC3493.
+ *    hostname and servname are pointers to null-terminated strings
+ *    or NULL. hostname is either a host name or a numeric host address
+ *    string: a dotted decimal IPv4 address or an IPv6 address. servname is
+ *    either a decimal port number or a service name as listed in
+ *    /etc/services.
+ *
+ *    If the operating system does not provide a struct addrinfo, the
+ *    following structure is used:
+ *
+ * \code
+ * struct  addrinfo {
+ *         int             ai_flags;       // AI_PASSIVE, AI_CANONNAME
+ *         int             ai_family;      // PF_xxx
+ *         int             ai_socktype;    // SOCK_xxx
+ *         int             ai_protocol;    // 0 or IPPROTO_xxx for IPv4 and IPv6
+ *         size_t          ai_addrlen;     // length of ai_addr
+ *         char            *ai_canonname;  // canonical name for hostname
+ *         struct sockaddr *ai_addr;       // binary address
+ *         struct addrinfo *ai_next;       // next structure in linked list
+ * };
+ * \endcode
+ *
+ *
+ *    hints is an optional pointer to a struct addrinfo. This structure can
+ *    be used to provide hints concerning the type of socket that the caller
+ *    supports or wishes to use. The caller can supply the following
+ *    structure elements in *hints:
+ *
+ * <ul>
+ *    <li>ai_family:
+ *           The protocol family that should be used. When ai_family is set
+ *           to PF_UNSPEC, it means the caller will accept any protocol
+ *           family supported by the operating system.</li>
+ *
+ *    <li>ai_socktype:
+ *           denotes the type of socket -- SOCK_STREAM, SOCK_DGRAM or
+ *           SOCK_RAW -- that is wanted. When ai_socktype is zero the caller
+ *           will accept any socket type.</li>
+ *
+ *    <li>ai_protocol:
+ *           indicates which transport protocol is wanted: IPPROTO_UDP or
+ *           IPPROTO_TCP. If ai_protocol is zero the caller will accept any
+ *           protocol.</li>
+ *
+ *    <li>ai_flags:
+ *           Flag bits. If the AI_CANONNAME bit is set, a successful call to
+ *           getaddrinfo() will return a null-terminated string
+ *           containing the canonical name of the specified hostname in
+ *           ai_canonname of the first addrinfo structure returned. Setting
+ *           the AI_PASSIVE bit indicates that the returned socket address
+ *           structure is intended for used in a call to bind(2). In this
+ *           case, if the hostname argument is a NULL pointer, then the IP
+ *           address portion of the socket address structure will be set to
+ *           INADDR_ANY for an IPv4 address or IN6ADDR_ANY_INIT for an IPv6
+ *           address.<br /><br />
+ *
+ *           When ai_flags does not set the AI_PASSIVE bit, the returned
+ *           socket address structure will be ready for use in a call to
+ *           connect(2) for a connection-oriented protocol or connect(2),
+ *           sendto(2), or sendmsg(2) if a connectionless protocol was
+ *           chosen. The IP address portion of the socket address structure
+ *           will be set to the loopback address if hostname is a NULL
+ *           pointer and AI_PASSIVE is not set in ai_flags.<br /><br />
+ *
+ *           If ai_flags is set to AI_NUMERICHOST it indicates that hostname
+ *           should be treated as a numeric string defining an IPv4 or IPv6
+ *           address and no name resolution should be attempted.
+ * </li></ul>
+ *
+ *    All other elements of the struct addrinfo passed via hints must be
+ *    zero.
+ *
+ *    A hints of NULL is treated as if the caller provided a struct addrinfo
+ *    initialized to zero with ai_familyset to PF_UNSPEC.
+ *
+ *    After a successful call to getaddrinfo(), *res is a pointer to a
+ *    linked list of one or more addrinfo structures. Each struct addrinfo
+ *    in this list cn be processed by following the ai_next pointer, until a
+ *    NULL pointer is encountered. The three members ai_family, ai_socktype,
+ *    and ai_protocol in each returned addrinfo structure contain the
+ *    corresponding arguments for a call to socket(2). For each addrinfo
+ *    structure in the list, the ai_addr member points to a filled-in socket
+ *    address structure of length ai_addrlen.
+ *
+ *    All of the information returned by getaddrinfo() is dynamically
+ *    allocated: the addrinfo structures, and the socket address structures
+ *    and canonical host name strings pointed to by the addrinfostructures.
+ *    Memory allocated for the dynamically allocated structures created by a
+ *    successful call to getaddrinfo() is released by freeaddrinfo().
+ *    ai is a pointer to a struct addrinfo created by a call to getaddrinfo().
+ *
+ * \section irsreturn RETURN VALUES
+ *
+ *    getaddrinfo() returns zero on success or one of the error codes
+ *    listed in gai_strerror() if an error occurs. If both hostname and
+ *    servname are NULL getaddrinfo() returns #EAI_NONAME.
+ *
+ * \section irssee SEE ALSO
+ *
+ *    getaddrinfo(), freeaddrinfo(),
+ *    gai_strerror(), RFC3493, getservbyname(3), connect(2),
+ *    sendto(2), sendmsg(2), socket(2).
+ */
+
+#include <errno.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef _WIN32
+#include <windows.h>
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#endif /* ifdef _WIN32 */
+
+#include <isc/app.h>
+#include <isc/buffer.h>
+#include <isc/lib.h>
+#include <isc/mem.h>
+#include <isc/mutex.h>
+#include <isc/print.h>
+#include <isc/sockaddr.h>
+#include <isc/string.h>
+#include <isc/util.h>
+
+#include <dns/client.h>
+#include <dns/fixedname.h>
+#include <dns/name.h>
+#include <dns/rdata.h>
+#include <dns/rdataset.h>
+#include <dns/rdatastruct.h>
+#include <dns/rdatatype.h>
+#include <dns/result.h>
+
+#include <irs/context.h>
+#include <irs/netdb.h>
+#include <irs/resconf.h>
+
+#define SA(addr)     ((struct sockaddr *)(addr))
+#define SIN(addr)    ((struct sockaddr_in *)(addr))
+#define SIN6(addr)   ((struct sockaddr_in6 *)(addr))
+#define SLOCAL(addr) ((struct sockaddr_un *)(addr))
+
+/*! \struct addrinfo
+ */
+static struct addrinfo *
+ai_concat(struct addrinfo *ai1, struct addrinfo *ai2),
+	*ai_reverse(struct addrinfo *oai),
+	*ai_clone(struct addrinfo *oai, int family),
+	*ai_alloc(int family, int addrlen);
+#ifdef AF_LOCAL
+static int
+get_local(const char *name, int socktype, struct addrinfo **res);
+#endif /* ifdef AF_LOCAL */
+
+static int
+resolve_name(int family, const char *hostname, int flags, struct addrinfo **aip,
+	     int socktype, int port);
+
+static int
+add_ipv4(const char *hostname, int flags, struct addrinfo **aip, int socktype,
+	 int port);
+static int
+add_ipv6(const char *hostname, int flags, struct addrinfo **aip, int socktype,
+	 int port);
+static void
+set_order(int, int (**)(const char *, int, struct addrinfo **, int, int));
+static void
+_freeaddrinfo(struct addrinfo *ai);
+
+#define FOUND_IPV4 0x1
+#define FOUND_IPV6 0x2
+#define FOUND_MAX  2
+
+/*%
+ * Try converting the scope identifier in 'src' to a network interface index.
+ * Upon success, return true and store the resulting index in 'dst'.  Upon
+ * failure, return false.
+ */
+static bool
+parse_scopeid(const char *src, uint32_t *dst) {
+	uint32_t scopeid = 0;
+
+	REQUIRE(src != NULL);
+	REQUIRE(dst != NULL);
+
+#ifdef HAVE_IF_NAMETOINDEX
+	/*
+	 * Try using if_nametoindex() first if it is available.  As it does not
+	 * handle numeric scopes, we do not simply return if it fails.
+	 */
+	scopeid = (uint32_t)if_nametoindex(src);
+#endif /* ifdef HAVE_IF_NAMETOINDEX */
+
+	/*
+	 * Fall back to numeric scope processing if if_nametoindex() either
+	 * fails or is unavailable.
+	 */
+	if (scopeid == 0) {
+		char *endptr = NULL;
+		scopeid = (uint32_t)strtoul(src, &endptr, 10);
+		/*
+		 * The scope identifier must not be empty and no trailing
+		 * characters are allowed after it.
+		 */
+		if (src == endptr || endptr == NULL || *endptr != '\0') {
+			return (false);
+		}
+	}
+
+	*dst = scopeid;
+
+	return (true);
+}
+
+#define ISC_AI_MASK (AI_PASSIVE | AI_CANONNAME | AI_NUMERICHOST)
+/*%
+ * Get a list of IP addresses and port numbers for host hostname and
+ * service servname.
+ */
+int
+getaddrinfo(const char *hostname, const char *servname,
+	    const struct addrinfo *hints, struct addrinfo **res) {
+	struct servent *sp;
+	const char *proto;
+	int family, socktype, flags, protocol;
+	struct addrinfo *ai, *ai_list;
+	int err = 0;
+	int port, i;
+	int (*net_order[FOUND_MAX + 1])(const char *, int, struct addrinfo **,
+					int, int);
+
+	if (hostname == NULL && servname == NULL) {
+		return (EAI_NONAME);
+	}
+
+	proto = NULL;
+	if (hints != NULL) {
+		if ((hints->ai_flags & ~(ISC_AI_MASK)) != 0) {
+			return (EAI_BADFLAGS);
+		}
+		if (hints->ai_addrlen || hints->ai_canonname ||
+		    hints->ai_addr || hints->ai_next)
+		{
+			errno = EINVAL;
+			return (EAI_SYSTEM);
+		}
+		family = hints->ai_family;
+		socktype = hints->ai_socktype;
+		protocol = hints->ai_protocol;
+		flags = hints->ai_flags;
+		switch (family) {
+		case AF_UNSPEC:
+			switch (hints->ai_socktype) {
+			case SOCK_STREAM:
+				proto = "tcp";
+				break;
+			case SOCK_DGRAM:
+				proto = "udp";
+				break;
+			}
+			break;
+		case AF_INET:
+		case AF_INET6:
+			switch (hints->ai_socktype) {
+			case 0:
+				break;
+			case SOCK_STREAM:
+				proto = "tcp";
+				break;
+			case SOCK_DGRAM:
+				proto = "udp";
+				break;
+			case SOCK_RAW:
+				break;
+			default:
+				return (EAI_SOCKTYPE);
+			}
+			break;
+#ifdef AF_LOCAL
+		case AF_LOCAL:
+			switch (hints->ai_socktype) {
+			case 0:
+				break;
+			case SOCK_STREAM:
+				break;
+			case SOCK_DGRAM:
+				break;
+			default:
+				return (EAI_SOCKTYPE);
+			}
+			break;
+#endif /* ifdef AF_LOCAL */
+		default:
+			return (EAI_FAMILY);
+		}
+	} else {
+		protocol = 0;
+		family = 0;
+		socktype = 0;
+		flags = 0;
+	}
+
+#ifdef AF_LOCAL
+	/*!
+	 * First, deal with AF_LOCAL.  If the family was not set,
+	 * then assume AF_LOCAL if the first character of the
+	 * hostname/servname is '/'.
+	 */
+
+	if (hostname != NULL &&
+	    (family == AF_LOCAL || (family == 0 && *hostname == '/')))
+	{
+		return (get_local(hostname, socktype, res));
+	}
+
+	if (servname != NULL &&
+	    (family == AF_LOCAL || (family == 0 && *servname == '/')))
+	{
+		return (get_local(servname, socktype, res));
+	}
+#endif /* ifdef AF_LOCAL */
+
+	/*
+	 * Ok, only AF_INET and AF_INET6 left.
+	 */
+	ai_list = NULL;
+
+	/*
+	 * First, look up the service name (port) if it was
+	 * requested.  If the socket type wasn't specified, then
+	 * try and figure it out.
+	 */
+	if (servname != NULL) {
+		char *e;
+
+		port = strtol(servname, &e, 10);
+		if (*e == '\0') {
+			if (socktype == 0) {
+				return (EAI_SOCKTYPE);
+			}
+			if (port < 0 || port > 65535) {
+				return (EAI_SERVICE);
+			}
+			port = htons((unsigned short)port);
+		} else {
+#ifdef _WIN32
+			WORD wVersionRequested;
+			WSADATA wsaData;
+
+			wVersionRequested = MAKEWORD(2, 0);
+
+			err = WSAStartup(wVersionRequested, &wsaData);
+			if (err != 0) {
+				return (EAI_FAIL);
+			}
+#endif /* ifdef _WIN32 */
+			sp = getservbyname(servname, proto);
+			if (sp != NULL) {
+				port = sp->s_port;
+			}
+#ifdef _WIN32
+			WSACleanup();
+#endif /* ifdef _WIN32 */
+			if (sp == NULL) {
+				return (EAI_SERVICE);
+			}
+			if (socktype == 0) {
+				if (strcmp(sp->s_proto, "tcp") == 0) {
+					socktype = SOCK_STREAM;
+				} else if (strcmp(sp->s_proto, "udp") == 0) {
+					socktype = SOCK_DGRAM;
+				}
+			}
+		}
+	} else {
+		port = 0;
+	}
+
+	/*
+	 * Next, deal with just a service name, and no hostname.
+	 * (we verified that one of them was non-null up above).
+	 */
+	if (hostname == NULL && (flags & AI_PASSIVE) != 0) {
+		if (family == AF_INET || family == 0) {
+			ai = ai_alloc(AF_INET, sizeof(struct sockaddr_in));
+			if (ai == NULL) {
+				return (EAI_MEMORY);
+			}
+			ai->ai_socktype = socktype;
+			ai->ai_protocol = protocol;
+			SIN(ai->ai_addr)->sin_port = port;
+			ai->ai_next = ai_list;
+			ai_list = ai;
+		}
+
+		if (family == AF_INET6 || family == 0) {
+			ai = ai_alloc(AF_INET6, sizeof(struct sockaddr_in6));
+			if (ai == NULL) {
+				_freeaddrinfo(ai_list);
+				return (EAI_MEMORY);
+			}
+			ai->ai_socktype = socktype;
+			ai->ai_protocol = protocol;
+			SIN6(ai->ai_addr)->sin6_port = port;
+			ai->ai_next = ai_list;
+			ai_list = ai;
+		}
+
+		*res = ai_list;
+		return (0);
+	}
+
+	/*
+	 * If the family isn't specified or AI_NUMERICHOST specified, check
+	 * first to see if it is a numeric address.
+	 * Though the gethostbyname2() routine will recognize numeric addresses,
+	 * it will only recognize the format that it is being called for.  Thus,
+	 * a numeric AF_INET address will be treated by the AF_INET6 call as
+	 * a domain name, and vice versa.  Checking for both numerics here
+	 * avoids that.
+	 */
+	if (hostname != NULL && (family == 0 || (flags & AI_NUMERICHOST) != 0))
+	{
+		char abuf[sizeof(struct in6_addr)];
+		char nbuf[NI_MAXHOST];
+		int addrsize, addroff;
+		char ntmp[NI_MAXHOST];
+		uint32_t scopeid = 0;
+
+		/*
+		 * Scope identifier portion.
+		 */
+		ntmp[0] = '\0';
+		if (strchr(hostname, '%') != NULL) {
+			char *p;
+			strlcpy(ntmp, hostname, sizeof(ntmp));
+			p = strchr(ntmp, '%');
+
+			if (p != NULL && parse_scopeid(p + 1, &scopeid)) {
+				*p = '\0';
+			} else {
+				ntmp[0] = '\0';
+			}
+		}
+
+		if (inet_pton(AF_INET, hostname, (struct in_addr *)abuf) == 1) {
+			if (family == AF_INET6) {
+				/*
+				 * Convert to a V4 mapped address.
+				 */
+				struct in6_addr *a6 = (struct in6_addr *)abuf;
+				memmove(&a6->s6_addr[12], &a6->s6_addr[0], 4);
+				memset(&a6->s6_addr[10], 0xff, 2);
+				memset(&a6->s6_addr[0], 0, 10);
+				goto inet6_addr;
+			}
+			addrsize = sizeof(struct in_addr);
+			addroff = offsetof(struct sockaddr_in, sin_addr);
+			family = AF_INET;
+			goto common;
+		} else if (ntmp[0] != '\0' &&
+			   inet_pton(AF_INET6, ntmp, abuf) == 1)
+		{
+			if (family && family != AF_INET6) {
+				return (EAI_NONAME);
+			}
+			addrsize = sizeof(struct in6_addr);
+			addroff = offsetof(struct sockaddr_in6, sin6_addr);
+			family = AF_INET6;
+			goto common;
+		} else if (inet_pton(AF_INET6, hostname, abuf) == 1) {
+			if (family != 0 && family != AF_INET6) {
+				return (EAI_NONAME);
+			}
+		inet6_addr:
+			addrsize = sizeof(struct in6_addr);
+			addroff = offsetof(struct sockaddr_in6, sin6_addr);
+			family = AF_INET6;
+
+		common:
+			ai = ai_alloc(family,
+				      ((family == AF_INET6)
+					       ? sizeof(struct sockaddr_in6)
+					       : sizeof(struct sockaddr_in)));
+			if (ai == NULL) {
+				return (EAI_MEMORY);
+			}
+			ai_list = ai;
+			ai->ai_socktype = socktype;
+			SIN(ai->ai_addr)->sin_port = port;
+			memmove((char *)ai->ai_addr + addroff, abuf, addrsize);
+			if (ai->ai_family == AF_INET6) {
+				SIN6(ai->ai_addr)->sin6_scope_id = scopeid;
+			}
+			if ((flags & AI_CANONNAME) != 0) {
+				if (getnameinfo(ai->ai_addr,
+						(socklen_t)ai->ai_addrlen, nbuf,
+						sizeof(nbuf), NULL, 0,
+						NI_NUMERICHOST) == 0)
+				{
+					ai->ai_canonname = strdup(nbuf);
+					if (ai->ai_canonname == NULL) {
+						_freeaddrinfo(ai);
+						return (EAI_MEMORY);
+					}
+				} else {
+					/* XXX raise error? */
+					ai->ai_canonname = NULL;
+				}
+			}
+			goto done;
+		} else if ((flags & AI_NUMERICHOST) != 0) {
+			return (EAI_NONAME);
+		}
+	}
+
+	if (hostname == NULL && (flags & AI_PASSIVE) == 0) {
+		set_order(family, net_order);
+		for (i = 0; i < FOUND_MAX; i++) {
+			if (net_order[i] == NULL) {
+				break;
+			}
+			err = (net_order[i])(hostname, flags, &ai_list,
+					     socktype, port);
+			if (err != 0) {
+				if (ai_list != NULL) {
+					_freeaddrinfo(ai_list);
+					ai_list = NULL;
+				}
+				break;
+			}
+		}
+	} else {
+		err = resolve_name(family, hostname, flags, &ai_list, socktype,
+				   port);
+	}
+
+	if (ai_list == NULL) {
+		if (err == 0) {
+			err = EAI_NONAME;
+		}
+		return (err);
+	}
+
+done:
+	ai_list = ai_reverse(ai_list);
+
+	*res = ai_list;
+	return (0);
+}
+
+typedef struct gai_restrans {
+	dns_clientrestrans_t *xid;
+	bool is_inprogress;
+	int error;
+	struct addrinfo ai_sentinel;
+	struct gai_resstate *resstate;
+} gai_restrans_t;
+
+typedef struct gai_resstate {
+	isc_mem_t *mctx;
+	struct gai_statehead *head;
+	dns_fixedname_t fixedname;
+	dns_name_t *qname;
+	gai_restrans_t *trans4;
+	gai_restrans_t *trans6;
+	ISC_LINK(struct gai_resstate) link;
+} gai_resstate_t;
+
+typedef struct gai_statehead {
+	int ai_family;
+	int ai_flags;
+	int ai_socktype;
+	int ai_port;
+	isc_appctx_t *actx;
+	dns_client_t *dnsclient;
+	isc_mutex_t list_lock;
+	ISC_LIST(struct gai_resstate) resstates;
+	unsigned int activestates;
+} gai_statehead_t;
+
+static isc_result_t
+make_resstate(isc_mem_t *mctx, gai_statehead_t *head, const char *hostname,
+	      const char *domain, gai_resstate_t **statep) {
+	isc_result_t result;
+	gai_resstate_t *state;
+	dns_fixedname_t fixeddomain;
+	dns_name_t *qdomain;
+	unsigned int namelen;
+	isc_buffer_t b;
+	bool need_v4 = false;
+	bool need_v6 = false;
+
+	state = isc_mem_get(mctx, sizeof(*state));
+
+	/* Construct base domain name */
+	namelen = strlen(domain);
+	isc_buffer_constinit(&b, domain, namelen);
+	isc_buffer_add(&b, namelen);
+	qdomain = dns_fixedname_initname(&fixeddomain);
+	result = dns_name_fromtext(qdomain, &b, dns_rootname, 0, NULL);
+	if (result != ISC_R_SUCCESS) {
+		isc_mem_put(mctx, state, sizeof(*state));
+		return (result);
+	}
+
+	/* Construct query name */
+	namelen = strlen(hostname);
+	isc_buffer_constinit(&b, hostname, namelen);
+	isc_buffer_add(&b, namelen);
+	state->qname = dns_fixedname_initname(&state->fixedname);
+	result = dns_name_fromtext(state->qname, &b, qdomain, 0, NULL);
+	if (result != ISC_R_SUCCESS) {
+		isc_mem_put(mctx, state, sizeof(*state));
+		return (result);
+	}
+
+	if (head->ai_family == AF_UNSPEC || head->ai_family == AF_INET) {
+		need_v4 = true;
+	}
+	if (head->ai_family == AF_UNSPEC || head->ai_family == AF_INET6) {
+		need_v6 = true;
+	}
+
+	state->trans6 = NULL;
+	state->trans4 = NULL;
+	if (need_v4) {
+		state->trans4 = isc_mem_get(mctx, sizeof(gai_restrans_t));
+		state->trans4->error = 0;
+		state->trans4->xid = NULL;
+		state->trans4->resstate = state;
+		state->trans4->is_inprogress = true;
+		state->trans4->ai_sentinel.ai_next = NULL;
+	}
+	if (need_v6) {
+		state->trans6 = isc_mem_get(mctx, sizeof(gai_restrans_t));
+		state->trans6->error = 0;
+		state->trans6->xid = NULL;
+		state->trans6->resstate = state;
+		state->trans6->is_inprogress = true;
+		state->trans6->ai_sentinel.ai_next = NULL;
+	}
+
+	state->mctx = mctx;
+	state->head = head;
+	ISC_LINK_INIT(state, link);
+
+	*statep = state;
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+make_resstates(isc_mem_t *mctx, const char *hostname, gai_statehead_t *head,
+	       irs_resconf_t *resconf) {
+	isc_result_t result;
+	irs_resconf_searchlist_t *searchlist;
+	irs_resconf_search_t *searchent;
+	gai_resstate_t *resstate, *resstate0;
+
+	resstate0 = NULL;
+	result = make_resstate(mctx, head, hostname, ".", &resstate0);
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	searchlist = irs_resconf_getsearchlist(resconf);
+	for (searchent = ISC_LIST_HEAD(*searchlist); searchent != NULL;
+	     searchent = ISC_LIST_NEXT(searchent, link))
+	{
+		resstate = NULL;
+		result = make_resstate(mctx, head, hostname,
+				       (const char *)searchent->domain,
+				       &resstate);
+		if (result != ISC_R_SUCCESS) {
+			break;
+		}
+
+		ISC_LIST_APPEND(head->resstates, resstate, link);
+		head->activestates++;
+	}
+
+	/*
+	 * Insert the original hostname either at the head or the tail of the
+	 * state list, depending on the number of labels contained in the
+	 * original name and the 'ndots' configuration parameter.
+	 */
+	if (dns_name_countlabels(resstate0->qname) >
+	    irs_resconf_getndots(resconf) + 1)
+	{
+		ISC_LIST_PREPEND(head->resstates, resstate0, link);
+	} else {
+		ISC_LIST_APPEND(head->resstates, resstate0, link);
+	}
+	head->activestates++;
+
+	if (result != ISC_R_SUCCESS) {
+		while ((resstate = ISC_LIST_HEAD(head->resstates)) != NULL) {
+			ISC_LIST_UNLINK(head->resstates, resstate, link);
+			if (resstate->trans4 != NULL) {
+				isc_mem_put(mctx, resstate->trans4,
+					    sizeof(*resstate->trans4));
+			}
+			if (resstate->trans6 != NULL) {
+				isc_mem_put(mctx, resstate->trans6,
+					    sizeof(*resstate->trans6));
+			}
+
+			isc_mem_put(mctx, resstate, sizeof(*resstate));
+		}
+	}
+
+	return (result);
+}
+
+static void
+process_answer(isc_task_t *task, isc_event_t *event) {
+	int error = 0, family;
+	gai_restrans_t *trans = event->ev_arg;
+	gai_resstate_t *resstate;
+	dns_clientresevent_t *rev = (dns_clientresevent_t *)event;
+	dns_rdatatype_t qtype;
+	dns_name_t *name;
+	bool wantcname;
+
+	REQUIRE(trans != NULL);
+	resstate = trans->resstate;
+	REQUIRE(resstate != NULL);
+	REQUIRE(task != NULL);
+
+	if (trans == resstate->trans4) {
+		family = AF_INET;
+		qtype = dns_rdatatype_a;
+	} else {
+		INSIST(trans == resstate->trans6);
+		family = AF_INET6;
+		qtype = dns_rdatatype_aaaa;
+	}
+
+	INSIST(trans->is_inprogress);
+	trans->is_inprogress = false;
+
+	switch (rev->result) {
+	case ISC_R_SUCCESS:
+	case DNS_R_NCACHENXDOMAIN: /* treat this as a fatal error? */
+	case DNS_R_NCACHENXRRSET:
+		break;
+	default:
+		switch (rev->vresult) {
+		case DNS_R_SIGINVALID:
+		case DNS_R_SIGEXPIRED:
+		case DNS_R_SIGFUTURE:
+		case DNS_R_KEYUNAUTHORIZED:
+		case DNS_R_MUSTBESECURE:
+		case DNS_R_COVERINGNSEC:
+		case DNS_R_NOTAUTHORITATIVE:
+		case DNS_R_NOVALIDKEY:
+		case DNS_R_NOVALIDDS:
+		case DNS_R_NOVALIDSIG:
+			error = EAI_INSECUREDATA;
+			break;
+		default:
+			error = EAI_FAIL;
+		}
+		goto done;
+	}
+
+	wantcname = ((resstate->head->ai_flags & AI_CANONNAME) != 0);
+
+	/* Parse the response and construct the addrinfo chain */
+	for (name = ISC_LIST_HEAD(rev->answerlist); name != NULL;
+	     name = ISC_LIST_NEXT(name, link))
+	{
+		isc_result_t result;
+		dns_rdataset_t *rdataset;
+		char cname[1024];
+
+		if (wantcname) {
+			isc_buffer_t b;
+
+			isc_buffer_init(&b, cname, sizeof(cname));
+			result = dns_name_totext(name, true, &b);
+			if (result != ISC_R_SUCCESS) {
+				error = EAI_FAIL;
+				goto done;
+			}
+			isc_buffer_putuint8(&b, '\0');
+		}
+
+		for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL;
+		     rdataset = ISC_LIST_NEXT(rdataset, link))
+		{
+			if (!dns_rdataset_isassociated(rdataset)) {
+				continue;
+			}
+			if (rdataset->type != qtype) {
+				continue;
+			}
+
+			for (result = dns_rdataset_first(rdataset);
+			     result == ISC_R_SUCCESS;
+			     result = dns_rdataset_next(rdataset))
+			{
+				struct addrinfo *ai;
+				dns_rdata_t rdata;
+				dns_rdata_in_a_t rdata_a;
+				dns_rdata_in_aaaa_t rdata_aaaa;
+
+				ai = ai_alloc(
+					family,
+					((family == AF_INET6)
+						 ? sizeof(struct sockaddr_in6)
+						 : sizeof(struct sockaddr_in)));
+				if (ai == NULL) {
+					error = EAI_MEMORY;
+					goto done;
+				}
+				ai->ai_socktype = resstate->head->ai_socktype;
+				ai->ai_next = trans->ai_sentinel.ai_next;
+				trans->ai_sentinel.ai_next = ai;
+
+				/*
+				 * Set AF-specific parameters
+				 * (IPv4/v6 address/port)
+				 */
+				dns_rdata_init(&rdata);
+				switch (family) {
+				case AF_INET:
+					dns_rdataset_current(rdataset, &rdata);
+					result = dns_rdata_tostruct(
+						&rdata, &rdata_a, NULL);
+					RUNTIME_CHECK(result == ISC_R_SUCCESS);
+					SIN(ai->ai_addr)->sin_port =
+						resstate->head->ai_port;
+					memmove(&SIN(ai->ai_addr)->sin_addr,
+						&rdata_a.in_addr, 4);
+					dns_rdata_freestruct(&rdata_a);
+					break;
+				case AF_INET6:
+					dns_rdataset_current(rdataset, &rdata);
+					result = dns_rdata_tostruct(
+						&rdata, &rdata_aaaa, NULL);
+					RUNTIME_CHECK(result == ISC_R_SUCCESS);
+					SIN6(ai->ai_addr)->sin6_port =
+						resstate->head->ai_port;
+					memmove(&SIN6(ai->ai_addr)->sin6_addr,
+						&rdata_aaaa.in6_addr, 16);
+					dns_rdata_freestruct(&rdata_aaaa);
+					break;
+				}
+
+				if (wantcname) {
+					ai->ai_canonname = strdup(cname);
+					if (ai->ai_canonname == NULL) {
+						error = EAI_MEMORY;
+						goto done;
+					}
+				}
+			}
+		}
+	}
+
+done:
+	dns_client_freeresanswer(resstate->head->dnsclient, &rev->answerlist);
+	dns_client_destroyrestrans(&trans->xid);
+
+	isc_event_free(&event);
+
+	/* Make sure that error == 0 iff we have a non-empty list */
+	if (error == 0) {
+		if (trans->ai_sentinel.ai_next == NULL) {
+			error = EAI_NONAME;
+		}
+	} else {
+		if (trans->ai_sentinel.ai_next != NULL) {
+			_freeaddrinfo(trans->ai_sentinel.ai_next);
+			trans->ai_sentinel.ai_next = NULL;
+		}
+	}
+	trans->error = error;
+
+	/* Check whether we are done */
+	if ((resstate->trans4 == NULL || !resstate->trans4->is_inprogress) &&
+	    (resstate->trans6 == NULL || !resstate->trans6->is_inprogress))
+	{
+		/*
+		 * We're done for this state.  If there is no other outstanding
+		 * state, we can exit.
+		 */
+		resstate->head->activestates--;
+		if (resstate->head->activestates == 0) {
+			isc_app_ctxsuspend(resstate->head->actx);
+			return;
+		}
+
+		/*
+		 * There are outstanding states, but if we are at the head
+		 * of the state list (i.e., at the highest search priority)
+		 * and have any answer, we can stop now by canceling the
+		 * others.
+		 */
+		LOCK(&resstate->head->list_lock);
+		if (resstate == ISC_LIST_HEAD(resstate->head->resstates)) {
+			if ((resstate->trans4 != NULL &&
+			     resstate->trans4->ai_sentinel.ai_next != NULL) ||
+			    (resstate->trans6 != NULL &&
+			     resstate->trans6->ai_sentinel.ai_next != NULL))
+			{
+				gai_resstate_t *rest;
+
+				for (rest = ISC_LIST_NEXT(resstate, link);
+				     rest != NULL;
+				     rest = ISC_LIST_NEXT(rest, link))
+				{
+					if (rest->trans4 != NULL &&
+					    rest->trans4->xid != NULL)
+					{
+						dns_client_cancelresolve(
+							rest->trans4->xid);
+					}
+					if (rest->trans6 != NULL &&
+					    rest->trans6->xid != NULL)
+					{
+						dns_client_cancelresolve(
+							rest->trans6->xid);
+					}
+				}
+			} else {
+				/*
+				 * This search fails, so we move to the tail
+				 * of the list so that the next entry will
+				 * have the highest priority.
+				 */
+				ISC_LIST_UNLINK(resstate->head->resstates,
+						resstate, link);
+				ISC_LIST_APPEND(resstate->head->resstates,
+						resstate, link);
+			}
+		}
+		UNLOCK(&resstate->head->list_lock);
+	}
+}
+
+static int
+resolve_name(int family, const char *hostname, int flags, struct addrinfo **aip,
+	     int socktype, int port) {
+	isc_result_t result;
+	irs_context_t *irsctx;
+	irs_resconf_t *conf;
+	isc_mem_t *mctx;
+	isc_appctx_t *actx;
+	isc_task_t *task;
+	int terror = 0;
+	int error = 0;
+	dns_client_t *client;
+	gai_resstate_t *resstate;
+	gai_statehead_t head;
+	bool all_fail = true;
+
+	/* get IRS context and the associated parameters */
+	irsctx = NULL;
+	result = irs_context_get(&irsctx);
+	if (result != ISC_R_SUCCESS) {
+		return (EAI_FAIL);
+	}
+	actx = irs_context_getappctx(irsctx);
+
+	mctx = irs_context_getmctx(irsctx);
+	task = irs_context_gettask(irsctx);
+	conf = irs_context_getresconf(irsctx);
+	client = irs_context_getdnsclient(irsctx);
+
+	/* construct resolution states */
+	head.activestates = 0;
+	head.ai_family = family;
+	head.ai_socktype = socktype;
+	head.ai_flags = flags;
+	head.ai_port = port;
+	head.actx = actx;
+	head.dnsclient = client;
+	isc_mutex_init(&head.list_lock);
+
+	ISC_LIST_INIT(head.resstates);
+	result = make_resstates(mctx, hostname, &head, conf);
+	if (result != ISC_R_SUCCESS) {
+		isc_mutex_destroy(&head.list_lock);
+		return (EAI_FAIL);
+	}
+
+	LOCK(&head.list_lock);
+	for (resstate = ISC_LIST_HEAD(head.resstates); resstate != NULL;
+	     resstate = ISC_LIST_NEXT(resstate, link))
+	{
+		if (resstate->trans4 != NULL) {
+			result = dns_client_startresolve(
+				client, resstate->qname, dns_rdataclass_in,
+				dns_rdatatype_a, 0, task, process_answer,
+				resstate->trans4, &resstate->trans4->xid);
+			if (result == ISC_R_SUCCESS) {
+				resstate->trans4->is_inprogress = true;
+				all_fail = false;
+			} else {
+				resstate->trans4->is_inprogress = false;
+			}
+		}
+		if (resstate->trans6 != NULL) {
+			result = dns_client_startresolve(
+				client, resstate->qname, dns_rdataclass_in,
+				dns_rdatatype_aaaa, 0, task, process_answer,
+				resstate->trans6, &resstate->trans6->xid);
+			if (result == ISC_R_SUCCESS) {
+				resstate->trans6->is_inprogress = true;
+				all_fail = false;
+			} else {
+				resstate->trans6->is_inprogress = false;
+			}
+		}
+	}
+	UNLOCK(&head.list_lock);
+
+	if (!all_fail) {
+		/* Start all the events */
+		isc_app_ctxrun(actx);
+	} else {
+		error = EAI_FAIL;
+	}
+
+	/* Cleanup */
+	while ((resstate = ISC_LIST_HEAD(head.resstates)) != NULL) {
+		int terror4 = 0, terror6 = 0;
+
+		ISC_LIST_UNLINK(head.resstates, resstate, link);
+
+		if (*aip == NULL) {
+			struct addrinfo *sentinel4 = NULL;
+			struct addrinfo *sentinel6 = NULL;
+
+			if (resstate->trans4 != NULL) {
+				sentinel4 =
+					resstate->trans4->ai_sentinel.ai_next;
+				resstate->trans4->ai_sentinel.ai_next = NULL;
+			}
+			if (resstate->trans6 != NULL) {
+				sentinel6 =
+					resstate->trans6->ai_sentinel.ai_next;
+				resstate->trans6->ai_sentinel.ai_next = NULL;
+			}
+			*aip = ai_concat(sentinel4, sentinel6);
+		}
+
+		if (resstate->trans4 != NULL) {
+			INSIST(resstate->trans4->xid == NULL);
+			terror4 = resstate->trans4->error;
+			isc_mem_put(mctx, resstate->trans4,
+				    sizeof(*resstate->trans4));
+		}
+		if (resstate->trans6 != NULL) {
+			INSIST(resstate->trans6->xid == NULL);
+			terror6 = resstate->trans6->error;
+			isc_mem_put(mctx, resstate->trans6,
+				    sizeof(*resstate->trans6));
+		}
+
+		/*
+		 * If the entire lookup fails, we need to choose an appropriate
+		 * error code from individual codes.  We'll try to provide as
+		 * specific a code as possible.  In general, we are going to
+		 * find an error code other than EAI_NONAME (which is too
+		 * generic and may actually not be problematic in some cases).
+		 * EAI_NONAME will be set below if no better code is found.
+		 */
+		if (terror == 0 || terror == EAI_NONAME) {
+			if (terror4 != 0 && terror4 != EAI_NONAME) {
+				terror = terror4;
+			} else if (terror6 != 0 && terror6 != EAI_NONAME) {
+				terror = terror6;
+			}
+		}
+
+		isc_mem_put(mctx, resstate, sizeof(*resstate));
+	}
+
+	if (*aip == NULL) {
+		error = terror;
+		if (error == 0) {
+			error = EAI_NONAME;
+		}
+	}
+
+#if 1 /*  XXX: enabled for finding leaks.  should be cleaned up later. */
+	isc_app_ctxfinish(actx);
+	irs_context_destroy(&irsctx);
+#endif /* if 1 */
+
+	isc_mutex_destroy(&head.list_lock);
+	return (error);
+}
+
+static void
+set_order(int family,
+	  int (**net_order)(const char *, int, struct addrinfo **, int, int)) {
+	char *order, *tok, *last;
+	int found;
+
+	if (family) {
+		switch (family) {
+		case AF_INET:
+			*net_order++ = add_ipv4;
+			break;
+		case AF_INET6:
+			*net_order++ = add_ipv6;
+			break;
+		}
+	} else {
+		order = getenv("NET_ORDER");
+		found = 0;
+		if (order != NULL) {
+			last = NULL;
+			for (tok = strtok_r(order, ":", &last); tok;
+			     tok = strtok_r(NULL, ":", &last))
+			{
+				if (strcasecmp(tok, "inet6") == 0) {
+					if ((found & FOUND_IPV6) == 0) {
+						*net_order++ = add_ipv6;
+					}
+					found |= FOUND_IPV6;
+				} else if (strcasecmp(tok, "inet") == 0 ||
+					   strcasecmp(tok, "inet4") == 0)
+				{
+					if ((found & FOUND_IPV4) == 0) {
+						*net_order++ = add_ipv4;
+					}
+					found |= FOUND_IPV4;
+				}
+			}
+		}
+
+		/*
+		 * Add in anything that we didn't find.
+		 */
+		if ((found & FOUND_IPV4) == 0) {
+			*net_order++ = add_ipv4;
+		}
+		if ((found & FOUND_IPV6) == 0) {
+			*net_order++ = add_ipv6;
+		}
+	}
+	*net_order = NULL;
+	return;
+}
+
+static char v4_loop[4] = { 127, 0, 0, 1 };
+
+static int
+add_ipv4(const char *hostname, int flags, struct addrinfo **aip, int socktype,
+	 int port) {
+	struct addrinfo *ai;
+
+	UNUSED(hostname);
+	UNUSED(flags);
+
+	ai = ai_clone(*aip, AF_INET); /* don't use ai_clone() */
+	if (ai == NULL) {
+		return (EAI_MEMORY);
+	}
+
+	*aip = ai;
+	ai->ai_socktype = socktype;
+	SIN(ai->ai_addr)->sin_port = port;
+	memmove(&SIN(ai->ai_addr)->sin_addr, v4_loop, 4);
+
+	return (0);
+}
+
+static char v6_loop[16] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 };
+
+static int
+add_ipv6(const char *hostname, int flags, struct addrinfo **aip, int socktype,
+	 int port) {
+	struct addrinfo *ai;
+
+	UNUSED(hostname);
+	UNUSED(flags);
+
+	ai = ai_clone(*aip, AF_INET6); /* don't use ai_clone() */
+	if (ai == NULL) {
+		return (EAI_MEMORY);
+	}
+
+	*aip = ai;
+	ai->ai_socktype = socktype;
+	SIN6(ai->ai_addr)->sin6_port = port;
+	memmove(&SIN6(ai->ai_addr)->sin6_addr, v6_loop, 16);
+
+	return (0);
+}
+
+/*% Free address info. */
+void
+freeaddrinfo(struct addrinfo *ai) {
+	_freeaddrinfo(ai);
+}
+
+static void
+_freeaddrinfo(struct addrinfo *ai) {
+	struct addrinfo *ai_next;
+
+	while (ai != NULL) {
+		ai_next = ai->ai_next;
+		if (ai->ai_addr != NULL) {
+			free(ai->ai_addr);
+		}
+		if (ai->ai_canonname) {
+			free(ai->ai_canonname);
+		}
+		free(ai);
+		ai = ai_next;
+	}
+}
+
+#ifdef AF_LOCAL
+static int
+get_local(const char *name, int socktype, struct addrinfo **res) {
+	struct addrinfo *ai;
+	struct sockaddr_un *slocal;
+
+	if (socktype == 0) {
+		return (EAI_SOCKTYPE);
+	}
+
+	ai = ai_alloc(AF_LOCAL, sizeof(*slocal));
+	if (ai == NULL) {
+		return (EAI_MEMORY);
+	}
+
+	slocal = SLOCAL(ai->ai_addr);
+	strlcpy(slocal->sun_path, name, sizeof(slocal->sun_path));
+
+	ai->ai_socktype = socktype;
+	/*
+	 * ai->ai_flags, ai->ai_protocol, ai->ai_canonname,
+	 * and ai->ai_next were initialized to zero.
+	 */
+
+	*res = ai;
+	return (0);
+}
+#endif /* ifdef AF_LOCAL */
+
+/*!
+ * Allocate an addrinfo structure, and a sockaddr structure
+ * of the specified length.  We initialize:
+ *	ai_addrlen
+ *	ai_family
+ *	ai_addr
+ *	ai_addr->sa_family
+ *	ai_addr->sa_len	(IRS_PLATFORM_HAVESALEN)
+ * and everything else is initialized to zero.
+ */
+static struct addrinfo *
+ai_alloc(int family, int addrlen) {
+	struct addrinfo *ai;
+
+	ai = (struct addrinfo *)calloc(1, sizeof(*ai));
+	if (ai == NULL) {
+		return (NULL);
+	}
+
+	ai->ai_addr = SA(calloc(1, addrlen));
+	if (ai->ai_addr == NULL) {
+		free(ai);
+		return (NULL);
+	}
+	ai->ai_addrlen = addrlen;
+	ai->ai_family = family;
+	ai->ai_addr->sa_family = family;
+#ifdef IRS_PLATFORM_HAVESALEN
+	ai->ai_addr->sa_len = addrlen;
+#endif /* ifdef IRS_PLATFORM_HAVESALEN */
+	return (ai);
+}
+
+static struct addrinfo *
+ai_clone(struct addrinfo *oai, int family) {
+	struct addrinfo *ai;
+
+	ai = ai_alloc(family,
+		      ((family == AF_INET6) ? sizeof(struct sockaddr_in6)
+					    : sizeof(struct sockaddr_in)));
+
+	if (ai == NULL) {
+		return (NULL);
+	}
+	if (oai == NULL) {
+		return (ai);
+	}
+
+	ai->ai_flags = oai->ai_flags;
+	ai->ai_socktype = oai->ai_socktype;
+	ai->ai_protocol = oai->ai_protocol;
+	ai->ai_canonname = NULL;
+	ai->ai_next = oai;
+	return (ai);
+}
+
+static struct addrinfo *
+ai_reverse(struct addrinfo *oai) {
+	struct addrinfo *nai, *tai;
+
+	nai = NULL;
+
+	while (oai != NULL) {
+		/*
+		 * Grab one off the old list.
+		 */
+		tai = oai;
+		oai = oai->ai_next;
+		/*
+		 * Put it on the front of the new list.
+		 */
+		tai->ai_next = nai;
+		nai = tai;
+	}
+	return (nai);
+}
+
+static struct addrinfo *
+ai_concat(struct addrinfo *ai1, struct addrinfo *ai2) {
+	struct addrinfo *ai_tmp;
+
+	if (ai1 == NULL) {
+		return (ai2);
+	} else if (ai2 == NULL) {
+		return (ai1);
+	}
+
+	for (ai_tmp = ai1; ai_tmp != NULL && ai_tmp->ai_next != NULL;
+	     ai_tmp = ai_tmp->ai_next)
+	{
+	}
+
+	ai_tmp->ai_next = ai2;
+
+	return (ai1);
+}