dns cache per interface iteration 2

name server addresses are read from the dns
cache associated wih the interface on which
the request shall be done.

processes which has requested to issue dns request
using specific interface are now proxied to netd.

added methods to attach/detach a process to a specific
dns cache/interface.

added getaddrinfoforinface method which takes an
interface as an argument.

Change-Id: I851ec8ab8ce3112626ad2a729078b91d013f32fd
bug:4815099
bug:5465296

2 files changed, 53 insertions, 56 deletions

diff --git a/libc/netbsd/net/getaddrinfo.c b/libc/netbsd/net/getaddrinfo.c
index 326b09c..4e23132 100644
--- a/libc/netbsd/net/getaddrinfo.c
+++ b/libc/netbsd/net/getaddrinfo.c
@@ -214,7 +214,7 @@ struct res_target {
 
 static int str2number(const char *);
 static int explore_fqdn(const struct addrinfo *, const char *,
-	const char *, struct addrinfo **);
+	const char *, struct addrinfo **, const char *iface);
 static int explore_null(const struct addrinfo *,
 	const char *, struct addrinfo **);
 static int explore_numeric(const struct addrinfo *, const char *,
@@ -402,17 +402,15 @@ _have_ipv4() {
         return _test_connect(PF_INET, &addr.generic, sizeof(addr.in));
 }
 
-// Returns 0 on success, else returns non-zero on error (in which case
-// getaddrinfo should continue as normal)
+// Returns 0 on success, else returns on error.
 static int
 android_getaddrinfo_proxy(
     const char *hostname, const char *servname,
-    const struct addrinfo *hints, struct addrinfo **res)
+    const struct addrinfo *hints, struct addrinfo **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;
 	int success = 0;
 
@@ -421,33 +419,17 @@ android_getaddrinfo_proxy(
 	// allocated in the process (before failing).
 	*res = NULL;
 
-	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.
+	// Bogus things we can't serialize.  Don't use the proxy.  These will fail - let them.
 	if ((hostname != NULL &&
 	     strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) ||
 	    (servname != NULL &&
 	     strcspn(servname, " \n\r\t^'\"") != strlen(servname))) {
-		return -1;
+		return EAI_NODATA;
 	}
 
 	sock = socket(AF_UNIX, SOCK_STREAM, 0);
 	if (sock < 0) {
-		return -1;
+		return EAI_NODATA;
 	}
 
 	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
@@ -459,18 +441,20 @@ android_getaddrinfo_proxy(
 				       (const struct sockaddr*) &proxy_addr,
 				       sizeof(proxy_addr))) != 0) {
 		close(sock);
-		return -1;
+		return EAI_NODATA;
 	}
 
 	// Send the request.
 	proxy = fdopen(sock, "r+");
-	if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d",
+	if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d %s %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) < 0) {
+		    hints == NULL ? -1 : hints->ai_protocol,
+		    iface == NULL ? "^" : iface,
+		    getpid()) < 0) {
 		goto exit;
 	}
 	// literal NULL byte at end, required by FrameworkListener
@@ -580,20 +564,26 @@ exit:
 		return 0;
 	}
 
-	// Proxy failed; fall through to local
-	// resolver case.  But first clean up any
-	// memory we might've allocated.
+	// Proxy failed;
+	// clean up memory we might've allocated.
 	if (*res) {
 		freeaddrinfo(*res);
 		*res = NULL;
 	}
-	return -1;
+	return EAI_NODATA;
 }
 
 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;
@@ -601,12 +591,12 @@ getaddrinfo(const char *hostname, const char *servname,
 	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;
@@ -739,9 +729,10 @@ getaddrinfo(const char *hostname, const char *servname,
         /*
          * BEGIN ANDROID CHANGES; proxying to the cache
          */
-        if (android_getaddrinfo_proxy(hostname, servname, hints, res) == 0) {
-            return 0;
-        }
+	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);
+	}
 
 	/*
 	 * hostname as alphabetical name.
@@ -770,7 +761,7 @@ getaddrinfo(const char *hostname, const char *servname,
 			pai->ai_protocol = ex->e_protocol;
 
 		error = explore_fqdn(pai, hostname, servname,
-			&cur->ai_next);
+			&cur->ai_next, iface);
 
 		while (cur && cur->ai_next)
 			cur = cur->ai_next;
@@ -803,7 +794,7 @@ getaddrinfo(const char *hostname, const char *servname,
  */
 static int
 explore_fqdn(const struct addrinfo *pai, const char *hostname,
-    const char *servname, struct addrinfo **res)
+    const char *servname, struct addrinfo **res, const char *iface)
 {
 	struct addrinfo *result;
 	struct addrinfo *cur;
@@ -829,7 +820,7 @@ explore_fqdn(const struct addrinfo *pai, const char *hostname,
 		return 0;
 
 	switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
-			default_dns_files, hostname, pai)) {
+			default_dns_files, hostname, pai, iface)) {
 	case NS_TRYAGAIN:
 		error = EAI_AGAIN;
 		goto free;
@@ -1897,9 +1888,11 @@ _dns_getaddrinfo(void *rv, void	*cb_data, va_list ap)
 	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));
@@ -1981,6 +1974,12 @@ _dns_getaddrinfo(void *rv, void	*cb_data, va_list ap)
 		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 d8ac037..7ab48e6 100644
--- a/libc/netbsd/net/getnameinfo.c
+++ b/libc/netbsd/net/getnameinfo.c
@@ -99,7 +99,7 @@ struct sockinet {
 };
 
 static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *,
-    socklen_t, char *, socklen_t, int));
+    socklen_t, char *, socklen_t, int, const char*));
 #ifdef INET6
 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
 				 socklen_t, int));
@@ -122,28 +122,33 @@ static const int DnsProxyQueryResult = 222;
  */
 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);
+				serv, servlen, flags, iface);
 #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) {
+android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr, socklen_t addrLen, int addrFamily, const char* iface)
+{
 
 	int sock;
 	const int one = 1;
@@ -158,15 +163,6 @@ android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr,
 		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) {
@@ -195,7 +191,8 @@ android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr,
 	if (addrStr == NULL) {
 		goto exit;
 	}
-	if (fprintf(proxy, "gethostbyaddr %s %d %d", addrStr, addrLen, addrFamily) < 0) {
+	if (fprintf(proxy, "gethostbyaddr %s %d %d %d %s",
+			addrStr, addrLen, addrFamily, getpid(), iface == NULL ? "^" : iface) < 0) {
 		goto exit;
 	}
 
@@ -246,7 +243,7 @@ android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr,
  * Format an IPv4 or IPv6 sockaddr into a printable string.
  */
 static int
-getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
+getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags, iface)
 	const struct sockaddr *sa;
 	socklen_t salen;
 	char *host;
@@ -254,6 +251,7 @@ getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
 	char *serv;
 	socklen_t servlen;
 	int flags;
+	const char* iface;
 {
 	const struct afd *afd;
 	struct servent *sp;
@@ -398,14 +396,14 @@ getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
 		char android_proxy_buf[MAXDNAME];
 
 		int hostnamelen = android_gethostbyaddr_proxy(android_proxy_buf,
-				MAXDNAME, addr, afd->a_addrlen, afd->a_af);
+				MAXDNAME, addr, afd->a_addrlen, afd->a_af, iface);
 		if (hostnamelen > 0) {
 			hp = &android_proxy_hostent;
 			hp->h_name = android_proxy_buf;
 		} else if (!hostnamelen) {
 			hp = NULL;
 		} else {
-			hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
+			hp = android_gethostbyaddrforiface(addr, afd->a_addrlen, afd->a_af, iface);
 		}
 #else
 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);