#3 move dnsd_read from dns.c to iodined.c, now named read_dns

src/dns.c

@@ -249,6 +249,11 @@ dns_decode(char *buf, size_t buflen, struct query *q, qr_t qr, char *packet, siz
 	rv = 0;
 	header = (HEADER*)packet;
 
+	// Reject short packets
+	if (packetlen < sizeof(HEADER)) {
+		return rv;
+	}
+	
 	if (header->qr != qr) {
 		warnx("header->qr does not match the requested qr");
 		return -1;
@@ -442,32 +447,3 @@ decodepacket(const char *name, char *buf, int buflen)
 	return len;
 }
 
-int
-dnsd_read(int fd, struct query *q, char *buf, int buflen)
-{
-	struct sockaddr_in from;
-	char packet[64*1024];
-	socklen_t addrlen;
-	int len;
-	int rv;
-	int r;
-
-	addrlen = sizeof(struct sockaddr);
-	r = recvfrom(fd, packet, sizeof(packet), 0, (struct sockaddr*)&from, &addrlen);
-
-	if (r >= sizeof(HEADER)) {
-		len = dns_decode(buf, buflen, q, QR_QUERY, packet, r);
-
-		q->fromlen = addrlen;
-		memcpy((struct sockaddr*)&q->from, (struct sockaddr*)&from, addrlen);
-		rv = len;
-	} else if (r < 0) { 	// Error
-		perror("recvfrom");
-		rv = 0;
-	} else {		// Packet too small to be dns protocol
-		rv = 0;
-	}
-
-	return rv;
-}
-

src/dns.h

@@ -37,7 +37,6 @@ int dns_encode_hostname(const char *, char *, int);
 int dns_encode(char *, size_t, struct query *, qr_t, char *, size_t);
 int dns_decode(char *, size_t, struct query *, qr_t, char *, size_t);
 
-int dnsd_read(int, struct query*, char *, int);
 void dnsd_send(int, struct query*, char *, int);
 
 int dnsd_haspacket();

src/iodined.c

@@ -56,6 +56,8 @@ char password[33];
 int my_mtu;
 in_addr_t my_ip;
 
+static int read_dns(int, struct query *, char *, int);
+
 static void
 sigint(int sig) {
 	running = 0;
@@ -120,7 +122,7 @@ tunnel(int tun_fd, int dns_fd)
 				outpacket.len = outlen;
 			}
 			if(FD_ISSET(dns_fd, &fds)) {
-				read = dnsd_read(dns_fd, &q, in, sizeof(in));
+				read = read_dns(dns_fd, &q, in, sizeof(in));
 				if (read <= 0)
 			   		continue;
 
@@ -217,6 +219,33 @@ tunnel(int tun_fd, int dns_fd)
 	return 0;
 }
 
+static int
+read_dns(int fd, struct query *q, char *buf, int buflen)
+{
+	struct sockaddr_in from;
+	char packet[64*1024];
+	socklen_t addrlen;
+	int len;
+	int rv;
+	int r;
+
+	addrlen = sizeof(struct sockaddr);
+	r = recvfrom(fd, packet, sizeof(packet), 0, (struct sockaddr*)&from, &addrlen);
+
+	if (r > 0) {
+		len = dns_decode(buf, buflen, q, QR_QUERY, packet, r);
+
+		q->fromlen = addrlen;
+		memcpy((struct sockaddr*)&q->from, (struct sockaddr*)&from, addrlen);
+		rv = len;
+	} else if (r < 0) { 	// Error
+		perror("recvfrom");
+		rv = 0;
+	}
+
+	return rv;
+}
+
 static void
 usage() {
 	extern char *__progname;