Revert "dns cache per interface iteration 2"

This reverts commit f1464ff95670e6dcc0e12bf9fbbeb4c0346434c9

Change-Id: I3496b9a8cb54614fe3eea016d1391c8a89f3db38
diff --git a/libc/docs/OVERVIEW.TXT b/libc/docs/OVERVIEW.TXT
index a0a3493..753e48a 100644
--- a/libc/docs/OVERVIEW.TXT
+++ b/libc/docs/OVERVIEW.TXT
@@ -282,9 +282,16 @@
 
      - read /system/etc/resolv.conf instead of /etc/resolv.conf
 
-     - get the list of servers and the search domains for this process's
-       current interface from the dns cache.  This information is sent
-       from the framework via cache functions.
+     - read the list of servers from system properties. the code looks for
+       'net.dns1', 'net.dns2', etc.. Each property should contain the IP
+       address of a DNS server.
+
+       these properties are set/modified by other parts of the Android system
+       (e.g. the dhcpd daemon).
+
+       the implementation also supports per-process DNS server list, using the
+       properties 'net.dns1.<pid>', 'net.dns2.<pid>', etc... Where <pid> stands
+       for the numerical ID of the current process.
 
      - when performing a query, use a properly randomized Query ID (instead of
        a incremented one), for increased security.
diff --git a/libc/include/netdb.h b/libc/include/netdb.h
index 3ea512c..ead5954 100644
--- a/libc/include/netdb.h
+++ b/libc/include/netdb.h
@@ -207,13 +207,11 @@
 void endservent(void);
 void freehostent(struct hostent *);
 struct hostent	*gethostbyaddr(const void *, socklen_t, int);
-struct hostent	*android_gethostbyaddrforiface(const void *, socklen_t, int, const char*);
 int gethostbyaddr_r(const void *, int, int, struct hostent *, char *, size_t, struct hostent **, int *);
 struct hostent	*gethostbyname(const char *);
 int gethostbyname_r(const char *, struct hostent *, char *, size_t, struct hostent **, int *);
 struct hostent	*gethostbyname2(const char *, int);
 int gethostbyname2_r(const char *, int, struct hostent *, char *, size_t, struct hostent **, int *);
-struct hostent	*android_gethostbynameforiface(const char *, int, const char *);
 struct hostent	*gethostent(void);
 int gethostent_r(struct hostent *, char *, size_t, struct hostent **, int *);
 struct hostent	*getipnodebyaddr(const void *, size_t, int, int *);
@@ -241,9 +239,7 @@
 void setnetent(int);
 void setprotoent(int);
 int getaddrinfo(const char *, const char *, const struct addrinfo *, struct addrinfo **);
-int android_getaddrinfoforiface(const char *, const char *, const struct addrinfo *, const char *, struct addrinfo **);
 int getnameinfo(const struct sockaddr *, socklen_t, char *, size_t, char *, size_t, int);
-int android_getnameinfoforiface(const struct sockaddr *, socklen_t, char *, size_t, char *, size_t, int, const char *);
 void freeaddrinfo(struct addrinfo *);
 const char	*gai_strerror(int);
 void setnetgrent(const char *);
diff --git a/libc/netbsd/gethnamaddr.c b/libc/netbsd/gethnamaddr.c
index c59d1f1..9a9f6e2 100644
--- a/libc/netbsd/gethnamaddr.c
+++ b/libc/netbsd/gethnamaddr.c
@@ -56,7 +56,6 @@
 
 #include <sys/param.h>
 #include <sys/socket.h>
-#include <sys/un.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include "arpa_nameser.h"
@@ -70,7 +69,6 @@
 #include <stdio.h>
 #include <strings.h>
 #include <syslog.h>
-#include <unistd.h>
 
 #ifndef LOG_AUTH
 # define LOG_AUTH 0
@@ -82,9 +80,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-// This should be synchronized to ResponseCode.h
-static const int DnsProxyQueryResult = 222;
-
 static const char const AskedForGot[] =
 			  "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
 
@@ -126,7 +121,7 @@
 static int _dns_gethtbyaddr(void *, void *, va_list);
 static int _dns_gethtbyname(void *, void *, va_list);
 
-static struct hostent *gethostbyname_internal(const char *, int, res_state, const char *);
+static struct hostent *gethostbyname_internal(const char *, int, res_state);
 
 static const ns_src default_dns_files[] = {
 	{ NSSRC_FILES, 	NS_SUCCESS },
@@ -495,15 +490,14 @@
 
 	assert(name != NULL);
 
-	/* try IPv6 first - if that fails do IPv4 */
 	if (res->options & RES_USE_INET6) {
-		hp = gethostbyname_internal(name, AF_INET6, res, NULL);
+		hp = gethostbyname_internal(name, AF_INET6, res);
 		if (hp) {
 			__res_put_state(res);
 			return hp;
 		}
 	}
-	hp = gethostbyname_internal(name, AF_INET, res, NULL);
+	hp = gethostbyname_internal(name, AF_INET, res);
 	__res_put_state(res);
 	return hp;
 }
@@ -511,145 +505,25 @@
 struct hostent *
 gethostbyname2(const char *name, int af)
 {
-	return android_gethostbynameforiface(name, af, NULL);
-}
-
-struct hostent *
-android_gethostbynameforiface(const char *name, int af, const char *iface)
-{
 	struct hostent *hp;
 	res_state res = __res_get_state();
 
 	if (res == NULL)
 		return NULL;
-	hp = gethostbyname_internal(name, af, res, iface);
+	hp = gethostbyname_internal(name, af, res);
 	__res_put_state(res);
 	return hp;
 }
 
-static struct hostent *gethostbyname_internal_real(const char *name, int af, res_state res);
-
-// very similar in proxy-ness to android_getaddrinfo_proxy
 static struct hostent *
-gethostbyname_internal(const char *name, int af, res_state res, const char *iface)
-{
-	int sock;
-	const int one = 1;
-	struct sockaddr_un proxy_addr;
-	const char *cache_mode = getenv("ANDROID_DNS_MODE");
-	FILE* proxy = NULL;
-
-	if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) {
-		res_setiface(res, iface);
-		return gethostbyname_internal_real(name, af, res);
-	}
-
-	sock = socket(AF_UNIX, SOCK_STREAM, 0);
-	if (sock < 0) {
-		return NULL;
-	}
-
-	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
-	memset(&proxy_addr, 0, sizeof(proxy_addr));
-	proxy_addr.sun_family = AF_UNIX;
-	strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", sizeof(proxy_addr.sun_path));
-	if (TEMP_FAILURE_RETRY(connect(sock,
-				       (const struct sockaddr*) &proxy_addr,
-				       sizeof(proxy_addr))) != 0) {
-		close(sock);
-		return NULL;
-	}
-
-	proxy = fdopen(sock, "r+");
-	/* This is writing to system/netd/DnsProxyListener.cpp and changes
-	 * here need to be matched there */
-	if (fprintf(proxy, "gethostbyname %d %s %d",
-		    getpid(),
-		    iface == NULL ? "^" : iface,
-		    name == NULL ? "^" : name,
-		    af) < 0) {
-		goto exit;
-	}
-
-	if (fputc(0, proxy) == EOF || fflush(proxy) != 0) {
-		goto exit;
-	}
-
-	uint32_t size;
-	char *buf = (char *)&size;
-	if (fread(buf, 1, sizeof(size), proxy) != 1) {
-		goto exit;
-	}
-
-	/* This is reading serialized data from system/netd/DnsProxyListener.cpp
-	 * and changes here need to be matched there */
-	int result_code = (int)strtol(buf, NULL, 10);
-	if (result_code != DnsProxyQueryResult) goto exit;
-
-	if (fread(buf, 1, sizeof(size), proxy) != 1) goto exit;
-	size = ntohl(size);
-
-	res_static rs = __res_get_static();
-	memset(&rs->host, 0, sizeof(rs->host));
-	char *ptr = rs->hostbuf;
-
-	if (fread(ptr, 1, size, proxy) != 1) goto exit;
-	ptr += size;
-	rs->host.h_name = rs->hostbuf;
-
-	char **aliases = rs->host_aliases;
-	rs->host.h_aliases = rs->host_aliases;
-	while (1) {
-		if (fread(buf, 1, sizeof(size), proxy) != 1) goto exit;
-		size = ntohl(size);
-		if (fread(ptr, 1, size, proxy) != 1) goto exit;
-		if (size == 1) {
-			*aliases = NULL;
-			break;
-		}
-		*aliases++ = ptr;
-		ptr += size;
-	}
-
-	if (fread(buf, 1, sizeof(size), proxy) != 1) goto exit;
-	rs->host.h_addrtype = ntohl(size);
-
-	if (fread(buf, 1, sizeof(size), proxy) != 1) goto exit;
-	rs->host.h_length = ntohl(size);
-
-	char **addrs = rs->h_addr_ptrs;
-	rs->host.h_addr_list = rs->h_addr_ptrs;
-	while (1) {
-		if (fread(buf, 1, sizeof(size), proxy) != 1) goto exit;
-		size = ntohl(size);
-		if (fread(ptr, 1, size, proxy) != 1) goto exit;
-		if (size == 1) {
-		    *addrs = NULL;
-		    break;
-		}
-		*addrs++ = ptr;
-		ptr += size;
-	}
-
-	fclose(proxy);
-	return &rs->host;
-
-exit:
-	if (proxy != NULL) {
-		fclose(proxy);
-	}
-	return NULL;
-}
-
-
-static struct hostent *
-gethostbyname_internal_real(const char *name, int af, res_state res)
+gethostbyname_internal(const char *name, int af, res_state res)
 {
 	const char *cp;
 	char *bp, *ep;
 	int size;
 	struct hostent *hp;
-	res_static rs = __res_get_static();
+        struct resolv_cache*  cache;
+        res_static  rs = __res_get_static();
 
 	static const ns_dtab dtab[] = {
 		NS_FILES_CB(_gethtbyname, NULL)
@@ -767,13 +641,6 @@
 gethostbyaddr(const void *addr,
     socklen_t len, int af)
 {
-	return android_gethostbyaddrforiface(addr, len, af, NULL);
-}
-
-struct hostent *
-android_gethostbyaddrforiface(const void *addr,
-    socklen_t len, int af, const char* iface)
-{
 	const u_char *uaddr = (const u_char *)addr;
 	socklen_t size;
 	struct hostent *hp;
@@ -820,7 +687,7 @@
 	hp = NULL;
 	h_errno = NETDB_INTERNAL;
 	if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyaddr",
-	    default_dns_files, uaddr, len, af, iface) != NS_SUCCESS)
+	    default_dns_files, uaddr, len, af) != NS_SUCCESS)
 		return NULL;
 	h_errno = NETDB_SUCCESS;
 	return hp;
@@ -1257,7 +1124,6 @@
 	const unsigned char *uaddr;
 	int len, af, advance;
 	res_state res;
-	const char* iface;
 	res_static rs = __res_get_static();
 
 	assert(rv != NULL);
@@ -1265,7 +1131,6 @@
 	uaddr = va_arg(ap, unsigned char *);
 	len = va_arg(ap, int);
 	af = va_arg(ap, int);
-	iface = va_arg(ap, char *);
 
 	switch (af) {
 	case AF_INET:
@@ -1307,8 +1172,6 @@
 		free(buf);
 		return NS_NOTFOUND;
 	}
-	res_setiface(res, iface);
-	_resolv_populate_res_for_iface(res);
 	n = res_nquery(res, qbuf, C_IN, T_PTR, buf->buf, sizeof(buf->buf));
 	if (n < 0) {
 		free(buf);
diff --git a/libc/netbsd/net/getaddrinfo.c b/libc/netbsd/net/getaddrinfo.c
index 4e23132..326b09c 100644
--- a/libc/netbsd/net/getaddrinfo.c
+++ b/libc/netbsd/net/getaddrinfo.c
@@ -214,7 +214,7 @@
 
 static int str2number(const char *);
 static int explore_fqdn(const struct addrinfo *, const char *,
-	const char *, struct addrinfo **, const char *iface);
+	const char *, struct addrinfo **);
 static int explore_null(const struct addrinfo *,
 	const char *, struct addrinfo **);
 static int explore_numeric(const struct addrinfo *, const char *,
@@ -402,15 +402,17 @@
         return _test_connect(PF_INET, &addr.generic, sizeof(addr.in));
 }
 
-// Returns 0 on success, else returns on error.
+// Returns 0 on success, else returns non-zero on error (in which case
+// getaddrinfo should continue as normal)
 static int
 android_getaddrinfo_proxy(
     const char *hostname, const char *servname,
-    const struct addrinfo *hints, struct addrinfo **res, const char *iface)
+    const struct addrinfo *hints, struct addrinfo **res)
 {
 	int sock;
 	const int one = 1;
 	struct sockaddr_un proxy_addr;
+	const char* cache_mode = getenv("ANDROID_DNS_MODE");
 	FILE* proxy = NULL;
 	int success = 0;
 
@@ -419,17 +421,33 @@
 	// allocated in the process (before failing).
 	*res = NULL;
 
-	// Bogus things we can't serialize.  Don't use the proxy.  These will fail - let them.
+	if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) {
+		// Don't use the proxy in local mode.  This is used by the
+		// proxy itself.
+		return -1;
+	}
+
+	// Temporary cautious hack to disable the DNS proxy for processes
+	// requesting special treatment.  Ideally the DNS proxy should
+	// accomodate these apps, though.
+	char propname[PROP_NAME_MAX];
+	char propvalue[PROP_VALUE_MAX];
+	snprintf(propname, sizeof(propname), "net.dns1.%d", getpid());
+	if (__system_property_get(propname, propvalue) > 0) {
+		return -1;
+	}
+
+	// Bogus things we can't serialize.  Don't use the proxy.
 	if ((hostname != NULL &&
 	     strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) ||
 	    (servname != NULL &&
 	     strcspn(servname, " \n\r\t^'\"") != strlen(servname))) {
-		return EAI_NODATA;
+		return -1;
 	}
 
 	sock = socket(AF_UNIX, SOCK_STREAM, 0);
 	if (sock < 0) {
-		return EAI_NODATA;
+		return -1;
 	}
 
 	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
@@ -441,20 +459,18 @@
 				       (const struct sockaddr*) &proxy_addr,
 				       sizeof(proxy_addr))) != 0) {
 		close(sock);
-		return EAI_NODATA;
+		return -1;
 	}
 
 	// Send the request.
 	proxy = fdopen(sock, "r+");
-	if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d %s %d",
+	if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d",
 		    hostname == NULL ? "^" : hostname,
 		    servname == NULL ? "^" : servname,
 		    hints == NULL ? -1 : hints->ai_flags,
 		    hints == NULL ? -1 : hints->ai_family,
 		    hints == NULL ? -1 : hints->ai_socktype,
-		    hints == NULL ? -1 : hints->ai_protocol,
-		    iface == NULL ? "^" : iface,
-		    getpid()) < 0) {
+		    hints == NULL ? -1 : hints->ai_protocol) < 0) {
 		goto exit;
 	}
 	// literal NULL byte at end, required by FrameworkListener
@@ -564,26 +580,20 @@
 		return 0;
 	}
 
-	// Proxy failed;
-	// clean up memory we might've allocated.
+	// Proxy failed; fall through to local
+	// resolver case.  But first clean up any
+	// memory we might've allocated.
 	if (*res) {
 		freeaddrinfo(*res);
 		*res = NULL;
 	}
-	return EAI_NODATA;
+	return -1;
 }
 
 int
 getaddrinfo(const char *hostname, const char *servname,
     const struct addrinfo *hints, struct addrinfo **res)
 {
-	return android_getaddrinfoforiface(hostname, servname, hints, NULL, res);
-}
-
-int
-android_getaddrinfoforiface(const char *hostname, const char *servname,
-    const struct addrinfo *hints, const char *iface, struct addrinfo **res)
-{
 	struct addrinfo sentinel;
 	struct addrinfo *cur;
 	int error = 0;
@@ -591,12 +601,12 @@
 	struct addrinfo ai0;
 	struct addrinfo *pai;
 	const struct explore *ex;
-	const char* cache_mode = getenv("ANDROID_DNS_MODE");
 
 	/* hostname is allowed to be NULL */
 	/* servname is allowed to be NULL */
 	/* hints is allowed to be NULL */
 	assert(res != NULL);
+
 	memset(&sentinel, 0, sizeof(sentinel));
 	cur = &sentinel;
 	pai = &ai;
@@ -729,10 +739,9 @@
         /*
          * BEGIN ANDROID CHANGES; proxying to the cache
          */
-	if (cache_mode == NULL || strcmp(cache_mode, "local") != 0) {
-		// we're not the proxy - pass the request to them
-		return android_getaddrinfo_proxy(hostname, servname, hints, res, iface);
-	}
+        if (android_getaddrinfo_proxy(hostname, servname, hints, res) == 0) {
+            return 0;
+        }
 
 	/*
 	 * hostname as alphabetical name.
@@ -761,7 +770,7 @@
 			pai->ai_protocol = ex->e_protocol;
 
 		error = explore_fqdn(pai, hostname, servname,
-			&cur->ai_next, iface);
+			&cur->ai_next);
 
 		while (cur && cur->ai_next)
 			cur = cur->ai_next;
@@ -794,7 +803,7 @@
  */
 static int
 explore_fqdn(const struct addrinfo *pai, const char *hostname,
-    const char *servname, struct addrinfo **res, const char *iface)
+    const char *servname, struct addrinfo **res)
 {
 	struct addrinfo *result;
 	struct addrinfo *cur;
@@ -820,7 +829,7 @@
 		return 0;
 
 	switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
-			default_dns_files, hostname, pai, iface)) {
+			default_dns_files, hostname, pai)) {
 	case NS_TRYAGAIN:
 		error = EAI_AGAIN;
 		goto free;
@@ -1888,11 +1897,9 @@
 	struct addrinfo sentinel, *cur;
 	struct res_target q, q2;
 	res_state res;
-	const char* iface;
 
 	name = va_arg(ap, char *);
 	pai = va_arg(ap, const struct addrinfo *);
-	iface = va_arg(ap, char *);
 	//fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name);
 
 	memset(&q, 0, sizeof(q));
@@ -1974,12 +1981,6 @@
 		return NS_NOTFOUND;
 	}
 
-	/* this just sets our iface val in the thread private data so we don't have to
-	 * modify the api's all the way down to res_send.c's res_nsend.  We could
-	 * fully populate the thread private data here, but if we get down there
-	 * and have a cache hit that would be wasted, so we do the rest there on miss
-	 */
-	res_setiface(res, iface);
 	if (res_searchN(name, &q, res) < 0) {
 		__res_put_state(res);
 		free(buf);
diff --git a/libc/netbsd/net/getnameinfo.c b/libc/netbsd/net/getnameinfo.c
index 7ab48e6..d8ac037 100644
--- a/libc/netbsd/net/getnameinfo.c
+++ b/libc/netbsd/net/getnameinfo.c
@@ -99,7 +99,7 @@
 };
 
 static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *,
-    socklen_t, char *, socklen_t, int, const char*));
+    socklen_t, char *, socklen_t, int));
 #ifdef INET6
 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
 				 socklen_t, int));
@@ -122,33 +122,28 @@
  */
 int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags)
 {
-	return android_getnameinfoforiface(sa, salen, host, hostlen, serv, servlen, flags, NULL);
-}
-
-int android_getnameinfoforiface(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags, const char* iface)
-{
 	switch (sa->sa_family) {
 	case AF_INET:
 	case AF_INET6:
 		return getnameinfo_inet(sa, salen, host, hostlen,
-				serv, servlen, flags, iface);
+		    serv, servlen, flags);
 #if defined(ANDROID_CHANGES) && defined(AF_LINK)
 	case AF_LINK:
 		return getnameinfo_link(sa, salen, host, hostlen,
-				serv, servlen, flags);
+		    serv, servlen, flags);
 #endif
 	default:
 		return EAI_FAMILY;
 	}
 }
+
 #ifdef ANDROID_CHANGES
 /* On success length of the host name is returned. A return
  * value of 0 means there's no host name associated with
  * the address. On failure -1 is returned in which case
  * normal execution flow shall continue. */
 static int
-android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr, socklen_t addrLen, int addrFamily, const char* iface)
-{
+android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr, socklen_t addrLen, int addrFamily) {
 
 	int sock;
 	const int one = 1;
@@ -163,6 +158,15 @@
 		return -1;
 	}
 
+	// Temporary cautious hack to disable the DNS proxy for processes
+	// requesting special treatment.  Ideally the DNS proxy should
+	// accomodate these apps, though.
+	char propname[PROP_NAME_MAX];
+	char propvalue[PROP_VALUE_MAX];
+	snprintf(propname, sizeof(propname), "net.dns1.%d", getpid());
+	if (__system_property_get(propname, propvalue) > 0) {
+		return -1;
+	}
 	// create socket
 	sock = socket(AF_UNIX, SOCK_STREAM, 0);
 	if (sock < 0) {
@@ -191,8 +195,7 @@
 	if (addrStr == NULL) {
 		goto exit;
 	}
-	if (fprintf(proxy, "gethostbyaddr %s %d %d %d %s",
-			addrStr, addrLen, addrFamily, getpid(), iface == NULL ? "^" : iface) < 0) {
+	if (fprintf(proxy, "gethostbyaddr %s %d %d", addrStr, addrLen, addrFamily) < 0) {
 		goto exit;
 	}
 
@@ -243,7 +246,7 @@
  * Format an IPv4 or IPv6 sockaddr into a printable string.
  */
 static int
-getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags, iface)
+getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
 	const struct sockaddr *sa;
 	socklen_t salen;
 	char *host;
@@ -251,7 +254,6 @@
 	char *serv;
 	socklen_t servlen;
 	int flags;
-	const char* iface;
 {
 	const struct afd *afd;
 	struct servent *sp;
@@ -396,14 +398,14 @@
 		char android_proxy_buf[MAXDNAME];
 
 		int hostnamelen = android_gethostbyaddr_proxy(android_proxy_buf,
-				MAXDNAME, addr, afd->a_addrlen, afd->a_af, iface);
+				MAXDNAME, addr, afd->a_addrlen, afd->a_af);
 		if (hostnamelen > 0) {
 			hp = &android_proxy_hostent;
 			hp->h_name = android_proxy_buf;
 		} else if (!hostnamelen) {
 			hp = NULL;
 		} else {
-			hp = android_gethostbyaddrforiface(addr, afd->a_addrlen, afd->a_af, iface);
+			hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
 		}
 #else
 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
diff --git a/libc/netbsd/resolv/res_cache.c b/libc/netbsd/resolv/res_cache.c
index 23f5c24..afc9a36 100644
--- a/libc/netbsd/resolv/res_cache.c
+++ b/libc/netbsd/resolv/res_cache.c
@@ -43,7 +43,6 @@
 #include <arpa/inet.h>
 #include "resolv_private.h"
 #include "resolv_iface.h"
-#include "res_private.h"
 
 /* This code implements a small and *simple* DNS resolver cache.
  *
@@ -1250,16 +1249,9 @@
     struct resolv_cache_info*   next;
     char*                       nameservers[MAXNS +1];
     struct addrinfo*            nsaddrinfo[MAXNS + 1];
-    char                        defdname[256];
-    int                         dnsrch_offset[MAXDNSRCH+1];  // offsets into defdname
+    char*                       domains;
 } CacheInfo;
 
-typedef struct resolv_pidiface_info {
-    int                             pid;
-    char                            ifname[IF_NAMESIZE + 1];
-    struct resolv_pidiface_info*    next;
-} PidIfaceInfo;
-
 #define  HTABLE_VALID(x)  ((x) != NULL && (x) != HTABLE_DELETED)
 
 static void
@@ -1312,7 +1304,6 @@
             }
         } else {
             struct timespec ts = {0,0};
-            XLOG("Waiting for previous request");
             ts.tv_sec = _time_now() + PENDING_REQUEST_TIMEOUT;
             pthread_cond_timedwait(&ri->cond, &cache->lock, &ts);
         }
@@ -1408,8 +1399,9 @@
     if (cache_mode == NULL || strcmp(cache_mode, "local") != 0) {
         // Don't use the cache in local mode.  This is used by the
         // proxy itself.
-        XLOG("setup cache for non-cache process. size=0, %s", cache_mode);
-        return 0;
+        // TODO - change this to 0 when all dns stuff uses proxy (5918973)
+        XLOG("setup cache for non-cache process. size=1");
+        return 1;
     }
 
     if (__system_property_get(DNS_CACHE_SIZE_PROP_NAME, cache_size) > 0) {
@@ -1548,7 +1540,7 @@
 
         pnode = &node->hlink;
     }
-    return pnode;
+    return pnode; 
 }
 
 /* Add a new entry to the hash table. 'lookup' must be the
@@ -1789,28 +1781,20 @@
 /****************************************************************************/
 /****************************************************************************/
 
-static pthread_once_t        _res_cache_once = PTHREAD_ONCE_INIT;
+static pthread_once_t        _res_cache_once;
 
 // Head of the list of caches.  Protected by _res_cache_list_lock.
 static struct resolv_cache_info _res_cache_list;
 
-// List of pid iface pairs
-static struct resolv_pidiface_info _res_pidiface_list;
-
 // name of the current default inteface
 static char            _res_default_ifname[IF_NAMESIZE + 1];
 
 // lock protecting everything in the _resolve_cache_info structs (next ptr, etc)
 static pthread_mutex_t _res_cache_list_lock;
 
-// lock protecting the _res_pid_iface_list
-static pthread_mutex_t _res_pidiface_list_lock;
 
 /* lookup the default interface name */
 static char *_get_default_iface_locked();
-/* find the first cache that has an associated interface and return the name of the interface */
-static char* _find_any_iface_name_locked( void );
-
 /* insert resolv_cache_info into the list of resolv_cache_infos */
 static void _insert_cache_info_locked(struct resolv_cache_info* cache_info);
 /* creates a resolv_cache_info */
@@ -1831,14 +1815,8 @@
 static struct addrinfo* _get_nameserver_addr_locked(const char* ifname, int n);
 /* lookup the inteface's address */
 static struct in_addr* _get_addr_locked(const char * ifname);
-/* return 1 if the provided list of name servers differs from the list of name servers
- * currently attached to the provided cache_info */
-static int _resolv_is_nameservers_equal_locked(struct resolv_cache_info* cache_info,
-        char** servers, int numservers);
-/* remove a resolv_pidiface_info structure from _res_pidiface_list */
-static void _remove_pidiface_info_locked(int pid);
-/* get a resolv_pidiface_info structure from _res_pidiface_list with a certain pid */
-static struct resolv_pidiface_info* _get_pid_iface_info_locked(int pid);
+
+
 
 static void
 _res_cache_init(void)
@@ -1852,36 +1830,37 @@
 
     memset(&_res_default_ifname, 0, sizeof(_res_default_ifname));
     memset(&_res_cache_list, 0, sizeof(_res_cache_list));
-    memset(&_res_pidiface_list, 0, sizeof(_res_pidiface_list));
     pthread_mutex_init(&_res_cache_list_lock, NULL);
-    pthread_mutex_init(&_res_pidiface_list_lock, NULL);
 }
 
 struct resolv_cache*
-__get_res_cache(const char* ifname)
+__get_res_cache(void)
 {
     struct resolv_cache *cache;
 
     pthread_once(&_res_cache_once, _res_cache_init);
+
     pthread_mutex_lock(&_res_cache_list_lock);
 
-    char* iface;
-    if (ifname == NULL || ifname[0] == '\0') {
-        iface = _get_default_iface_locked();
-        if (iface[0] == '\0') {
-            char* tmp = _find_any_iface_name_locked();
-            if (tmp) {
-                iface = tmp;
-            }
-        }
-    } else {
-        iface = (char *) ifname;
-    }
+    char* ifname = _get_default_iface_locked();
 
-    cache = _get_res_cache_for_iface_locked(iface);
+    // if default interface not set then use the first cache
+    // associated with an interface as the default one.
+    if (ifname[0] == '\0') {
+        struct resolv_cache_info* cache_info = _res_cache_list.next;
+        while (cache_info) {
+            if (cache_info->ifname[0] != '\0') {
+                ifname = cache_info->ifname;
+                break;
+            }
+
+            cache_info = cache_info->next;
+        }
+    }
+    cache = _get_res_cache_for_iface_locked(ifname);
 
     pthread_mutex_unlock(&_res_cache_list_lock);
-    XLOG("_get_res_cache: iface = %s, cache=%p\n", iface, cache);
+    XLOG("_get_res_cache. default_ifname = %s\n", ifname);
     return cache;
 }
 
@@ -2037,29 +2016,11 @@
 static char*
 _get_default_iface_locked(void)
 {
-
     char* iface = _res_default_ifname;
 
     return iface;
 }
 
-static char*
-_find_any_iface_name_locked( void ) {
-    char* ifname = NULL;
-
-    struct resolv_cache_info* cache_info = _res_cache_list.next;
-    while (cache_info) {
-        if (cache_info->ifname[0] != '\0') {
-            ifname = cache_info->ifname;
-            break;
-        }
-
-        cache_info = cache_info->next;
-    }
-
-    return ifname;
-}
-
 void
 _resolv_set_default_iface(const char* ifname)
 {
@@ -2083,19 +2044,16 @@
     int i, rt, index;
     struct addrinfo hints;
     char sbuf[NI_MAXSERV];
-    register char *cp;
-    int *offset;
 
     pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_cache_list_lock);
 
+    pthread_mutex_lock(&_res_cache_list_lock);
     // creates the cache if not created
     _get_res_cache_for_iface_locked(ifname);
 
     struct resolv_cache_info* cache_info = _find_cache_info_locked(ifname);
 
-    if (cache_info != NULL &&
-            !_resolv_is_nameservers_equal_locked(cache_info, servers, numservers)) {
+    if (cache_info != NULL) {
         // free current before adding new
         _free_nameservers_locked(cache_info);
 
@@ -2111,68 +2069,15 @@
             if (rt == 0) {
                 cache_info->nameservers[index] = strdup(servers[i]);
                 index++;
-                XLOG("_resolv_set_nameservers_for_iface: iface = %s, addr = %s\n",
-                        ifname, servers[i]);
             } else {
                 cache_info->nsaddrinfo[index] = NULL;
             }
         }
-
-        // code moved from res_init.c, load_domain_search_list
-        strlcpy(cache_info->defdname, domains, sizeof(cache_info->defdname));
-        if ((cp = strchr(cache_info->defdname, '\n')) != NULL)
-            *cp = '\0';
-        cp = cache_info->defdname;
-        offset = cache_info->dnsrch_offset;
-        while (offset < cache_info->dnsrch_offset + MAXDNSRCH) {
-            while (*cp == ' ' || *cp == '\t') /* skip leading white space */
-                cp++;
-            if (*cp == '\0') /* stop if nothing more to do */
-                break;
-            *offset++ = cp - cache_info->defdname; /* record this search domain */
-            while (*cp) { /* zero-terminate it */
-                if (*cp == ' '|| *cp == '\t') {
-                    *cp++ = '\0';
-                    break;
-                }
-                cp++;
-            }
-        }
-        *offset = -1; /* cache_info->dnsrch_offset has MAXDNSRCH+1 items */
-
-        // flush cache since new settings
-        _flush_cache_for_iface_locked(ifname);
-
+        cache_info->domains = strdup(domains);
     }
-
     pthread_mutex_unlock(&_res_cache_list_lock);
 }
 
-static int
-_resolv_is_nameservers_equal_locked(struct resolv_cache_info* cache_info,
-        char** servers, int numservers)
-{
-    int i;
-    char** ns;
-    int equal = 1;
-
-    // compare each name server against current name servers
-    if (numservers > MAXNS) numservers = MAXNS;
-    for (i = 0; i < numservers && equal; i++) {
-        ns = cache_info->nameservers;
-        equal = 0;
-        while(*ns) {
-            if (strcmp(*ns, servers[i]) == 0) {
-                equal = 1;
-                break;
-            }
-            ns++;
-        }
-    }
-
-    return equal;
-}
-
 static void
 _free_nameservers_locked(struct resolv_cache_info* cache_info)
 {
@@ -2315,192 +2220,3 @@
     }
     return NULL;
 }
-
-static void
-_remove_pidiface_info_locked(int pid) {
-    struct resolv_pidiface_info* result = &_res_pidiface_list;
-    struct resolv_pidiface_info* prev = NULL;
-
-    while (result != NULL && result->pid != pid) {
-        prev = result;
-        result = result->next;
-    }
-    if (prev != NULL && result != NULL) {
-        prev->next = result->next;
-        free(result);
-    }
-}
-
-static struct resolv_pidiface_info*
-_get_pid_iface_info_locked(int pid)
-{
-    struct resolv_pidiface_info* result = &_res_pidiface_list;
-    while (result != NULL && result->pid != pid) {
-        result = result->next;
-    }
-
-    return result;
-}
-
-void
-_resolv_set_iface_for_pid(const char* ifname, int pid)
-{
-    // make sure the pid iface list is created
-    pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_pidiface_list_lock);
-
-    struct resolv_pidiface_info* pidiface_info = _get_pid_iface_info_locked(pid);
-    if (!pidiface_info) {
-        pidiface_info = calloc(sizeof(*pidiface_info), 1);
-        if (pidiface_info) {
-            pidiface_info->pid = pid;
-            int len = sizeof(pidiface_info->ifname);
-            strncpy(pidiface_info->ifname, ifname, len - 1);
-            pidiface_info->ifname[len - 1] = '\0';
-
-            pidiface_info->next = _res_pidiface_list.next;
-            _res_pidiface_list.next = pidiface_info;
-
-            XLOG("_resolv_set_iface_for_pid: pid %d , iface %s\n", pid, ifname);
-        } else {
-            XLOG("_resolv_set_iface_for_pid failing calloc");
-        }
-    }
-
-    pthread_mutex_unlock(&_res_pidiface_list_lock);
-}
-
-void
-_resolv_clear_iface_for_pid(int pid)
-{
-    pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_pidiface_list_lock);
-
-    _remove_pidiface_info_locked(pid);
-
-    XLOG("_resolv_clear_iface_for_pid: pid %d\n", pid);
-
-    pthread_mutex_unlock(&_res_pidiface_list_lock);
-}
-
-int
-_resolv_get_pids_associated_interface(int pid, char* buff, int buffLen)
-{
-    int len = 0;
-
-    if (!buff) {
-        return -1;
-    }
-
-    pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_pidiface_list_lock);
-
-    struct resolv_pidiface_info* pidiface_info = _get_pid_iface_info_locked(pid);
-    buff[0] = '\0';
-    if (pidiface_info) {
-        len = strlen(pidiface_info->ifname);
-        if (len < buffLen) {
-            strncpy(buff, pidiface_info->ifname, len);
-            buff[len] = '\0';
-        }
-    }
-
-    XLOG("_resolv_get_pids_associated_interface buff: %s\n", buff);
-
-    pthread_mutex_unlock(&_res_pidiface_list_lock);
-
-    return len;
-}
-
-int
-_resolv_get_default_iface(char* buff, int buffLen)
-{
-    char* ifname;
-    int len = 0;
-
-    if (!buff || buffLen == 0) {
-        return -1;
-    }
-
-    pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_cache_list_lock);
-
-    ifname = _get_default_iface_locked();
-
-    // if default interface not set. Get first cache with an interface
-    if (ifname[0] == '\0') {
-        ifname = _find_any_iface_name_locked();
-    }
-
-    if (ifname) {
-        len = strlen(ifname);
-        if (len < buffLen) {
-            strncpy(buff, ifname, len);
-            buff[len] = '\0';
-        }
-    } else {
-        buff[0] = '\0';
-    }
-
-    pthread_mutex_unlock(&_res_cache_list_lock);
-
-    return len;
-}
-
-int
-_resolv_populate_res_for_iface(res_state statp)
-{
-    int nserv;
-    struct resolv_cache_info* info = NULL;
-
-    if (statp) {
-        struct addrinfo* ai;
-
-        if (statp->iface[0] == '\0') { // no interface set assign default
-            _resolv_get_default_iface(statp->iface, sizeof(statp->iface));
-        }
-
-        pthread_once(&_res_cache_once, _res_cache_init);
-        pthread_mutex_lock(&_res_cache_list_lock);
-        info = _find_cache_info_locked(statp->iface);
-
-        if (info == NULL) return 0;
-
-        XLOG("_resolv_populate_res_for_iface: %s\n", statp->iface);
-        for (nserv = 0; nserv < MAXNS; nserv++) {
-            ai = info->nsaddrinfo[nserv];
-            if (ai == NULL) {
-                break;
-            }
-
-            if ((size_t) ai->ai_addrlen <= sizeof(statp->_u._ext.ext->nsaddrs[0])) {
-                if (statp->_u._ext.ext != NULL) {
-                    memcpy(&statp->_u._ext.ext->nsaddrs[nserv], ai->ai_addr, ai->ai_addrlen);
-                    statp->nsaddr_list[nserv].sin_family = AF_UNSPEC;
-                } else {
-                    if ((size_t) ai->ai_addrlen
-                            <= sizeof(statp->nsaddr_list[0])) {
-                        memcpy(&statp->nsaddr_list[nserv], ai->ai_addr,
-                                ai->ai_addrlen);
-                    } else {
-                        statp->nsaddr_list[nserv].sin_family = AF_UNSPEC;
-                    }
-                }
-            } else {
-                XLOG("_resolv_populate_res_for_iface found too long addrlen");
-            }
-        }
-        statp->nscount = nserv;
-        // now do search domains.  Note that we cache the offsets as this code runs alot
-        // but the setting/offset-computer only runs when set/changed
-        strlcpy(statp->defdname, info->defdname, sizeof(statp->defdname));
-        register char **pp = statp->dnsrch;
-        register int *p = info->dnsrch_offset;
-        while (pp < statp->dnsrch + MAXDNSRCH && *p != -1) {
-            *pp++ = &statp->defdname + *p++;
-        }
-
-        pthread_mutex_unlock(&_res_cache_list_lock);
-    }
-    return nserv;
-}
diff --git a/libc/netbsd/resolv/res_data.c b/libc/netbsd/resolv/res_data.c
index 7e5a308..014c99b 100644
--- a/libc/netbsd/resolv/res_data.c
+++ b/libc/netbsd/resolv/res_data.c
@@ -82,7 +82,13 @@
 
 int  res_ourserver_p(const res_state, const struct sockaddr *);
 
+#ifdef ANDROID_CHANGES
+static int res_need_init() {
+	return ((_nres.options & RES_INIT) == 0U) || res_get_dns_changed();
+}
+#else
 #define res_need_init()   ((_nres.options & RES_INIT) == 0U)
+#endif
 
 int
 res_init(void) {
diff --git a/libc/netbsd/resolv/res_init.c b/libc/netbsd/resolv/res_init.c
index ff65299..56a25af 100644
--- a/libc/netbsd/resolv/res_init.c
+++ b/libc/netbsd/resolv/res_init.c
@@ -111,6 +111,13 @@
 /* ensure that sockaddr_in6 and IN6ADDR_ANY_INIT are declared / defined */
 #ifdef ANDROID_CHANGES
 #include "resolv_private.h"
+#define MAX_DNS_PROPERTIES 8
+#define DNS_PROP_NAME_PREFIX "net.dns"
+#define DNS_CHANGE_PROP_NAME "net.dnschange"
+#define DNS_SEARCH_PROP_NAME "net.dns.search"
+static const prop_info *dns_change_prop;
+static int dns_last_change_counter;
+static int _get_dns_change_count();
 #else
 #include <resolv.h>
 #endif
@@ -164,6 +171,41 @@
 	return (__res_vinit(statp, 0));
 }
 
+#ifdef ANDROID_CHANGES
+static int load_domain_search_list(res_state statp) {
+	char propvalue[PROP_VALUE_MAX];
+	register char *cp, **pp;
+
+	if(__system_property_get(DNS_SEARCH_PROP_NAME, propvalue) >= 1) {
+		strlcpy(statp->defdname, propvalue, sizeof(statp->defdname));
+		if ((cp = strchr(statp->defdname, '\n')) != NULL)
+			*cp = '\0';
+		cp = statp->defdname;
+		pp = statp->dnsrch;
+		while ( pp < statp->dnsrch + MAXDNSRCH ) {
+			while (*cp == ' ' || *cp == '\t') /* skip leading white space */
+				cp++;
+			if (*cp == '\0')  /* stop if nothing more */
+				break;
+			*pp++ = cp;  /* record this search domain */
+			while (*cp) { /* zero-terminate it */
+				if (*cp == ' ' || *cp == '\t') {
+					*cp++ = '\0';
+					break;
+				}
+				cp++;
+			}
+		}
+		*pp = NULL; /* statp->dnsrch has MAXDNSRCH+1 items */
+		if (pp > statp->dnsrch)
+			return 1;
+	}
+	statp->defdname[0] = '\0';  /* no default domain name on Android */
+	statp->dnsrch[0] = NULL;
+	return 0;
+}
+#endif
+
 /* This function has to be reachable by res_data.c but not publicly. */
 int
 __res_vinit(res_state statp, int preinit) {
@@ -178,6 +220,12 @@
 	char *net;
 	int dots;
 	union res_sockaddr_union u[2];
+#ifdef ANDROID_CHANGES
+        pid_t mypid = getpid();
+        int use_proc_props = 0;
+        int found_prop;
+	char dnsProperty[PROP_VALUE_MAX];
+#endif
 
         if ((statp->options & RES_INIT) != 0U)
                 res_ndestroy(statp);
@@ -270,8 +318,74 @@
 	if (nserv > 0)
 		statp->nscount = nserv;
 #endif
+#ifdef ANDROID_CHANGES /* READ FROM SYSTEM PROPERTIES */
+	dns_last_change_counter = _get_dns_change_count();
 
-#ifndef ANDROID_CHANGES /* !ANDROID_CHANGES - IGNORE resolv.conf in Android */
+	nserv = 0;
+	for(n = 1; n <= MAX_DNS_PROPERTIES && nserv < MAXNS; n++) {
+		char propname[PROP_NAME_MAX];
+		char propvalue[PROP_VALUE_MAX];
+
+		struct addrinfo hints, *ai;
+		char sbuf[NI_MAXSERV];
+		const size_t minsiz = sizeof(statp->_u._ext.ext->nsaddrs[0]);
+
+		/*
+		 * Check first for process-specific properties, and if those don't
+		 * exist, try the generic properties.
+		 */
+		found_prop = 0;
+		if (n == 1 || use_proc_props) {
+			snprintf(propname, sizeof(propname), "%s%d.%d", DNS_PROP_NAME_PREFIX, n, mypid);
+			if(__system_property_get(propname, propvalue) < 1) {
+				if (use_proc_props) {
+					break;
+				}
+			} else {
+				found_prop = 1;
+				use_proc_props = 1;
+			}
+		}
+		if (!found_prop) {
+			snprintf(propname, sizeof(propname), "%s%d", DNS_PROP_NAME_PREFIX, n);
+			if(__system_property_get(propname, propvalue) < 1) {
+				break;
+			}
+		}
+
+		cp = propvalue;
+
+		while (*cp == ' ' || *cp == '\t')
+			cp++;
+		cp[strcspn(cp, ";# \t\n")] = '\0';
+		if ((*cp != '\0') && (*cp != '\n')) {
+			memset(&hints, 0, sizeof(hints));
+			hints.ai_family = PF_UNSPEC;
+			hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
+			hints.ai_flags = AI_NUMERICHOST;
+			sprintf(sbuf, "%u", NAMESERVER_PORT);
+			if (getaddrinfo(cp, sbuf, &hints, &ai) == 0 &&
+			    (size_t)ai->ai_addrlen <= minsiz) {
+				if (statp->_u._ext.ext != NULL) {
+					memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
+					       ai->ai_addr, ai->ai_addrlen);
+				}
+				if ((size_t)ai->ai_addrlen <=
+				    sizeof(statp->nsaddr_list[nserv])) {
+					memcpy(&statp->nsaddr_list[nserv],
+					       ai->ai_addr, ai->ai_addrlen);
+				} else {
+					statp->nsaddr_list[nserv].sin_family = 0;
+				}
+				freeaddrinfo(ai);
+				nserv++;
+			}
+		}
+	}
+
+	/* Add the domain search list */
+	havesearch = load_domain_search_list(statp);
+#else /* !ANDROID_CHANGES - IGNORE resolv.conf in Android */
 #define	MATCH(line, name) \
 	(!strncmp(line, name, sizeof(name) - 1) && \
 	(line[sizeof(name) - 1] == ' ' || \
@@ -793,17 +907,32 @@
 }
 
 #ifdef ANDROID_CHANGES
-void res_setiface(res_state statp, const char* iface)
+static int _get_dns_change_count()
 {
-	if (statp != NULL) {
-		// set interface
-		if (iface && iface[0] != '\0') {
-			int len = sizeof(statp->iface);
-			strncpy(statp->iface, iface, len - 1);
-			statp->iface[len - 1] = '\0';
-		} else {
-			statp->iface[0] = '\0';
+	if (dns_change_prop == NULL) {
+		dns_change_prop = __system_property_find(DNS_CHANGE_PROP_NAME);
+	}
+	if (dns_change_prop != NULL) {
+		char propvalue[PROP_VALUE_MAX];
+		if (__system_property_read(dns_change_prop, NULL, propvalue) >= 1) {
+			return atoi(propvalue);
 		}
 	}
+	return -1;
+}
+
+int res_get_dns_changed()
+{
+	int change_count;
+
+	change_count = _get_dns_change_count();
+	if (change_count != dns_last_change_counter) {
+		if (change_count != -1) {
+			dns_last_change_counter = change_count;
+		}
+		return 1;
+	} else {
+		return 0;
+	}
 }
 #endif /* ANDROID_CHANGES */
diff --git a/libc/netbsd/resolv/res_send.c b/libc/netbsd/resolv/res_send.c
index 0be6e8e..f3ee539 100644
--- a/libc/netbsd/resolv/res_send.c
+++ b/libc/netbsd/resolv/res_send.c
@@ -370,13 +370,10 @@
         ResolvCacheStatus     cache_status = RESOLV_CACHE_UNSUPPORTED;
 #endif
 
-#if !USE_RESOLV_CACHE
 	if (statp->nscount == 0) {
 		errno = ESRCH;
 		return (-1);
 	}
-#endif
-
 	if (anssiz < HFIXEDSZ) {
 		errno = EINVAL;
 		return (-1);
@@ -388,8 +385,7 @@
 	terrno = ETIMEDOUT;
 
 #if USE_RESOLV_CACHE
-        // get the cache associated with the interface
-        cache = __get_res_cache(statp->iface);
+        cache = __get_res_cache();
         if (cache != NULL) {
             int  anslen = 0;
             cache_status = _resolv_cache_lookup(
@@ -398,17 +394,8 @@
 
             if (cache_status == RESOLV_CACHE_FOUND) {
                 return anslen;
-            } else {
-                // had a cache miss for a known interface, so populate the thread private
-                // data so the normal resolve path can do its thing
-                _resolv_populate_res_for_iface(statp);
             }
         }
-
-        if (statp->nscount == 0) {
-            errno = ESRCH;
-            return (-1);
-        }
 #endif
 
 	/*
diff --git a/libc/netbsd/resolv/res_state.c b/libc/netbsd/resolv/res_state.c
index efaa519..e05846a 100644
--- a/libc/netbsd/resolv/res_state.c
+++ b/libc/netbsd/resolv/res_state.c
@@ -50,7 +50,7 @@
 #endif
 
 static pthread_key_t   _res_key;
-static pthread_once_t  _res_once = PTHREAD_ONCE_INIT;
+static pthread_once_t  _res_once;
 
 typedef struct {
     int                  _h_errno;
diff --git a/libc/private/resolv_cache.h b/libc/private/resolv_cache.h
index 4f32fb7..1dcc53f 100644
--- a/libc/private/resolv_cache.h
+++ b/libc/private/resolv_cache.h
@@ -28,13 +28,13 @@
 #ifndef _RESOLV_CACHE_H_
 #define _RESOLV_CACHE_H_
 
-struct __res_state;
 struct resolv_cache;  /* forward */
 
-/* gets the cache for an interface. Set ifname argument to NULL or
- * empty buffer ('\0') to get cache for default interface.
- * returned cache might be NULL*/
-extern struct resolv_cache*  __get_res_cache(const char* ifname);
+/* gets the cache for the default interface. Might be NULL*/
+extern struct resolv_cache*  __get_res_cache(void);
+
+/* get the cache for a specified interface. Can be NULL*/
+extern struct resolv_cache* __get_res_cache_for_iface(const char* ifname);
 
 /* this gets called everytime we detect some changes in the DNS configuration
  * and will flush the cache */
@@ -67,14 +67,8 @@
 /* gets the address associated with the specified interface */
 extern struct in_addr* _resolv_get_addr_of_iface(const char* ifname);
 
-/* Copy the name of the default interface to provided buffer.
- * Return length of buffer on success on failure -1 is returned */
-extern int _resolv_get_default_iface(char* buff, int buffLen);
-
-/* sets the name server addresses to the provided res_state structure. The
- * name servers are retrieved from the cache which is associated
- * with the interface to which the res_state structure is associated */
-extern int _resolv_populate_res_for_iface(struct __res_state* statp);
+/* Get name of default interface */
+extern char* _resolv_get_default_iface();
 
 typedef enum {
     RESOLV_CACHE_UNSUPPORTED,  /* the cache can't handle that kind of queries */
diff --git a/libc/private/resolv_iface.h b/libc/private/resolv_iface.h
index bf5abad..3fe586e 100644
--- a/libc/private/resolv_iface.h
+++ b/libc/private/resolv_iface.h
@@ -60,21 +60,6 @@
 /* flush the cache associated with a certain interface */
 extern void _resolv_flush_cache_for_iface(const char* ifname);
 
-/* set a pid to use the name servers of the specified interface */
-extern void _resolv_set_iface_for_pid(const char* ifname, int pid);
-
-/* clear pid from being associated with an interface */
-extern void _resolv_clear_iface_for_pid(int pid);
-
-/** Gets the name of the interface to which the pid is attached.
- *  On error, -1 is returned.
- *  If no interface is found, 0 is returned and buff is set to empty ('\0').
- *  If an interface is found, the name is copied to buff and the length of the name is returned.
- *  Arguments:   pid The pid to find an interface for
- *               buff A buffer to copy the result to
- *               buffLen Length of buff. An interface is at most IF_NAMESIZE in length */
-extern int _resolv_get_pids_associated_interface(int pid, char* buff, int buffLen);
-
 #endif /* _BIONIC_RESOLV_IFACE_FUNCTIONS_DECLARED */
 
 __END_DECLS
diff --git a/libc/private/resolv_private.h b/libc/private/resolv_private.h
index 1c3c1a2..0f3c6c0 100644
--- a/libc/private/resolv_private.h
+++ b/libc/private/resolv_private.h
@@ -56,7 +56,6 @@
 
 #include <resolv.h>
 #include "resolv_static.h"
-#include <net/if.h>
 
 /*
  * Revision information.  This is the release date in YYYYMMDD format.
@@ -140,7 +139,6 @@
 struct __res_state_ext;
 
 struct __res_state {
-	char	iface[IF_NAMESIZE+1];
 	int	retrans;	 	/* retransmission time interval */
 	int	retry;			/* number of times to retransmit */
 #ifdef sun
@@ -493,7 +491,7 @@
 int		res_getservers(res_state,
 				    union res_sockaddr_union *, int);
 
-void res_setiface();
+int res_get_dns_changed();
 u_int  res_randomid(void);
 
 __END_DECLS