Allocate 64K recieve buffer for DNS responses.

KAME did the modification only to _dns_getaddrinfo().  However,
it is not sufficient, and res_queryN() should be modified, too.
So, I did same modification to res_queryN().

Obtained from:	KAME

1 files changed, 45 insertions, 20 deletions

diff --git a/lib/libc/net/getaddrinfo.c b/lib/libc/net/getaddrinfo.c
index ccd5d6e..847f162 100644
--- a/lib/libc/net/getaddrinfo.c
+++ b/lib/libc/net/getaddrinfo.c
@@ -201,11 +201,7 @@ static const ns_src default_dns_files[] = {
 	{ 0 }
 };
 
-#if PACKETSZ > 1024
-#define MAXPACKET	PACKETSZ
-#else
-#define MAXPACKET	1024
-#endif
+#define MAXPACKET	(64*1024)
 
 typedef union {
 	HEADER hdr;
@@ -1415,7 +1411,7 @@ _dns_getaddrinfo(rv, cb_data, ap)
 	va_list	 ap;
 {
 	struct addrinfo *ai;
-	querybuf buf, buf2;
+	querybuf *buf, *buf2;
 	const char *name;
 	const struct addrinfo *pai;
 	struct addrinfo sentinel, *cur;
@@ -1429,47 +1425,66 @@ _dns_getaddrinfo(rv, cb_data, ap)
 	memset(&sentinel, 0, sizeof(sentinel));
 	cur = &sentinel;
 
+	buf = malloc(sizeof(*buf));
+	if (!buf) {
+		h_errno = NETDB_INTERNAL;
+		return NS_NOTFOUND;
+	}
+	buf2 = malloc(sizeof(*buf2));
+	if (!buf2) {
+		free(buf);
+		h_errno = NETDB_INTERNAL;
+		return NS_NOTFOUND;
+	}
+
 	switch (pai->ai_family) {
 	case AF_UNSPEC:
 		/* prefer IPv6 */
 		q.qclass = C_IN;
 		q.qtype = T_AAAA;
-		q.answer = buf.buf;
-		q.anslen = sizeof(buf);
+		q.answer = buf->buf;
+		q.anslen = sizeof(buf->buf);
 		q.next = &q2;
 		q2.qclass = C_IN;
 		q2.qtype = T_A;
-		q2.answer = buf2.buf;
-		q2.anslen = sizeof(buf2);
+		q2.answer = buf2->buf;
+		q2.anslen = sizeof(buf2->buf);
 		break;
 	case AF_INET:
 		q.qclass = C_IN;
 		q.qtype = T_A;
-		q.answer = buf.buf;
-		q.anslen = sizeof(buf);
+		q.answer = buf->buf;
+		q.anslen = sizeof(buf->buf);
 		break;
 	case AF_INET6:
 		q.qclass = C_IN;
 		q.qtype = T_AAAA;
-		q.answer = buf.buf;
-		q.anslen = sizeof(buf);
+		q.answer = buf->buf;
+		q.anslen = sizeof(buf->buf);
 		break;
 	default:
+		free(buf);
+		free(buf2);
 		return NS_UNAVAIL;
 	}
-	if (res_searchN(name, &q) < 0)
+	if (res_searchN(name, &q) < 0) {
+		free(buf);
+		free(buf2);
 		return NS_NOTFOUND;
-	ai = getanswer(&buf, q.n, q.name, q.qtype, pai);
+	}
+	ai = getanswer(buf, q.n, q.name, q.qtype, pai);
 	if (ai) {
 		cur->ai_next = ai;
 		while (cur && cur->ai_next)
 			cur = cur->ai_next;
 	}
 	if (q.next) {
-		ai = getanswer(&buf2, q2.n, q2.name, q2.qtype, pai);
+		ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai);
 		if (ai)
 			cur->ai_next = ai;
 	}
+	free(buf);
+	free(buf2);
 	if (sentinel.ai_next == NULL)
 		switch (h_errno) {
 		case HOST_NOT_FOUND:
@@ -1772,7 +1787,7 @@ res_queryN(name, target)
 	const char *name;	/* domain name */
 	struct res_target *target;
 {
-	u_char buf[MAXPACKET];
+	u_char *buf;
 	HEADER *hp;
 	int n;
 	struct res_target *t;
@@ -1787,6 +1802,12 @@ res_queryN(name, target)
 		return (-1);
 	}
 
+	buf = malloc(MAXPACKET);
+	if (!buf) {
+		h_errno = NETDB_INTERNAL;
+		return -1;
+	}
+
 	for (t = target; t; t = t->next) {
 		int class, type;
 		u_char *answer;
@@ -1806,14 +1827,15 @@ res_queryN(name, target)
 #endif
 
 		n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,
-		    buf, sizeof(buf));
+		    buf, MAXPACKET);
 		if (n > 0 && (_res.options & RES_USE_EDNS0) != 0)
-			n = res_opt(n, buf, sizeof(buf), anslen);
+			n = res_opt(n, buf, MAXPACKET, anslen);
 		if (n <= 0) {
 #ifdef DEBUG
 			if (_res.options & RES_DEBUG)
 				printf(";; res_query: mkquery failed\n");
 #endif
+			free(buf);
 			h_errno = NO_RECOVERY;
 			return (n);
 		}
@@ -1824,6 +1846,7 @@ res_queryN(name, target)
 			if (_res.options & RES_DEBUG)
 				printf(";; res_query: send error\n");
 #endif
+			free(buf);
 			h_errno = TRY_AGAIN;
 			return (n);
 		}
@@ -1846,6 +1869,8 @@ res_queryN(name, target)
 		t->n = n;
 	}
 
+	free(buf);
+
 	if (ancount == 0) {
 		switch (rcode) {
 		case NXDOMAIN: