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-rw-r--r--ccast/ccmdns.c1096
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diff --git a/ccast/ccmdns.c b/ccast/ccmdns.c
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--- /dev/null
+++ b/ccast/ccmdns.c
@@ -0,0 +1,1096 @@
+
+/*
+ * Argyll Color Correction System
+ * ChromCast support
+ *
+ * Author: Graeme W. Gill
+ * Date: 28/8/2014
+ *
+ * Copyright 2014 Graeme W. Gill
+ * All rights reserved.
+ *
+ * This material is licenced under the GNU AFFERO GENERAL PUBLIC LICENSE Version 3 :-
+ * see the License2.txt file for licencing details.
+ *
+ */
+
+/*
+ * This class provides simple access to the Google ChromeCast
+ * for the purposes of generating Video Test patches.
+ */
+
+/*
+ TTBD: Ideally we should use the system mDNS resource if it is available,
+ and fall back to our mDNS code if not.
+
+ ie. Linux may have nothing, be using avahi-daemon,
+ possibly Zeroconf (== Bonjour ?)
+ Avahi has Bonjour compatibility library ??
+
+ ie. OS X is using mDNSRespo (Bonjour ?)
+
+ MSWin may have Bonjour installed on it ?
+ Has dns-sd command - what's that using (SSDP/UPnP ?)
+
+ From <http://stackoverflow.com/questions/8659638/how-does-windows-know-how-to-resolve-mdns-queries>
+
+ Bonjour for Windows allows any software using the standard name resolution APIs
+ to resolve mDNS names; it does so by registering a DLL (mdnsnsp.dll) as a
+ namespace provider using WSCInstallNameSpace.
+
+ The corresponding code is included in the mDNSResponder source (in particular,
+ look at the mdnsNSP and NSPTool components).
+
+ To test on Linux:
+
+ To check what's listening: sudo netstat -anp | grep 5353
+
+ /etc/init.d/avahi-daemon stop
+ /etc/init.d/avahi-daemon start
+
+ To test on OS X:
+
+ To check what's listening: sudo netstat -an | grep 5353
+
+ launchctl unload -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
+ launchctl load -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
+ */
+
+
+#include <time.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <math.h>
+#include <assert.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+#include "copyright.h"
+#include "aconfig.h"
+#include <sys/types.h>
+#ifndef SALONEINSTLIB
+#include "numlib.h"
+#else
+#include "numsup.h"
+#endif
+#include "ccmdns.h"
+
+#undef DEBUG
+
+#if defined(NT) // Windows specific
+# if _WIN32_WINNT < 0x0400
+# undef _WIN32_WINNT
+# define _WIN32_WINNT 0x0400 // To make it link in VS2005
+# endif
+# define WIN32_LEAN_AND_MEAN
+# include <winsock2.h>
+# include <windows.h>
+# include <ws2tcpip.h>
+
+# include <process.h>
+# include <direct.h>
+# include <io.h>
+
+# define ERRNO GetLastError()
+# define UDP_SOCKET_TIMEOUT WSAETIMEDOUT
+
+#else /* !NT = Unix, OS X */
+
+# include <errno.h>
+# include <sys/types.h>
+# include <sys/wait.h>
+# include <sys/socket.h>
+# include <sys/select.h>
+# include <netinet/in.h>
+# include <arpa/inet.h>
+# include <sys/time.h>
+# include <stdint.h>
+# include <inttypes.h>
+# include <netdb.h>
+
+# include <pwd.h>
+# include <unistd.h>
+# include <dirent.h>
+
+typedef int SOCKET;
+# define ERRNO errno
+
+# define INVALID_SOCKET -1
+# define SOCKET_ERROR -1
+# define UDP_SOCKET_TIMEOUT EAGAIN
+
+#define closesocket(xxx) close(xxx);
+
+#endif
+
+#ifdef DEBUG
+# define dbgo stdout
+# define DBG(xxx) fprintf xxx ;
+void cc_dump_bytes(FILE *fp, char *pfx, unsigned char *buf, int len);
+#else
+# define DBG(xxx) ;
+#endif /* DEBUG */
+
+/* ================================================================ */
+
+/* mDNS details */
+#define DESTINATION_MCAST "224.0.0.251"
+#define DESTINATION_MCASTV6 "FF02::FB"
+#define SOURCE_PORT 5353
+#define DESTINATION_PORT 5353
+
+#define BUFSIZE 1024
+
+/* Various DNS defines */
+#define DNS_CLASS_IN 0x0001
+
+// Used by ChromeCast
+#define DNS_TYPE_PTR 12 /* Domain name pointer */
+#define DNS_TYPE_TXT 16 /* Text String */
+#define DNS_TYPE_SRV 33 /* Server selection (SRV) record */
+#define DNS_TYPE_A 1 /* Host address (A) record */
+#define DNS_TYPE_AAAA 28 /* IPv6 address ??? */
+#define DNS_TYPE_NSEC 47 /* DNS Next Secure Name */
+
+
+#ifdef NEVER
+/* Print out a V6 address in zero compresed form */
+/* (It would be nice to add zero compression) */
+static char *print_IPV6_Address(ORD8 *buf) {
+ static char sbuf[40], *p = sbuf;
+ int i;
+ for (i = 0; i < 8; i++) {
+ p += sprintf(p, "%x", buf[i * 2 + 1] * 256 + buf[i * 2 + 0]);
+ if (i < 7)
+ *p++ = ':';
+ }
+ *p++ = '\000';
+ return sbuf;
+}
+#endif
+
+/* Write a DNS string to a buffer. */
+/* return the offset of the next byte after the string */
+static int write_string(ORD8 *buf, int off, char *s) {
+ int len = strlen(s);
+ if (len >= 0xc0)
+ len = 0xc0; // Hmm.
+ buf[off] = len;
+ off++;
+ memcpy(buf + off, s, len);
+ off += len;
+ return off;
+}
+
+/* Return NZ on error */
+static int init_mDNS() {
+
+#ifdef NT
+ WSADATA data;
+ if (WSAStartup(MAKEWORD(2,2), &data)) {
+ DBG((dbgo,"WSAStartup failed\n"))
+ return 1;
+ }
+#endif
+
+ return 0;
+}
+
+/* Setup the send socket */
+/* Return nz on error */
+static int init_send_mDNS(SOCKET *psock) {
+ int nRet, nOptVal;
+ int off;
+ SOCKET sock;
+ struct sockaddr_in stSourceAddr;
+
+ DBG((dbgo,"init_send_mDNS() called\n"))
+
+ /* get a datagram (UDP) socket */
+ sock = socket(PF_INET, SOCK_DGRAM, 0);
+ if (sock == INVALID_SOCKET) {
+ DBG((dbgo,"opening UDP socked failed with %d\n",ERRNO))
+ return 1;
+ }
+
+ /*----------------------- to send --------------------------- */
+
+ /* Theoretically, you do not need any special preparation to
+ * send to a multicast address. However, you may want a few
+ * things to overcome the limits of the default behavior
+ */
+
+ // If we're doing a one-shot, we shouldn't transmit from port 5353, */
+ // but ChromCast won't see the packet if we don't. */
+
+ /* We cant send from port 5353 if someone else is using it, */
+ /* so set the SO_REUSEADDR option (which is enough for MSWin), */
+ /* and SO_REUSEPORT for OS X and Linux */
+ {
+ int on = 1;
+ if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on))) {
+ DBG((dbgo,"setsockopt(SO_REUSEADDR) failed with %d\n",ERRNO))
+ closesocket(sock);
+ return 1;
+ }
+
+ /* Need this to be able to open port on Unix like systems */
+#ifndef NT
+# ifndef SO_REUSEPORT
+# ifdef __APPLE__
+# define SO_REUSEPORT 0x0200
+# else /* Linux */
+# define SO_REUSEPORT 15
+# endif
+# endif
+ if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, (const char *)&on, sizeof(on))) {
+ DBG((dbgo,"setsockopt(SO_REUSEPORT) failed with %d\n",ERRNO))
+ }
+#endif
+ }
+
+ /* init source address structure */
+ stSourceAddr.sin_family = PF_INET;
+ stSourceAddr.sin_port = htons(SOURCE_PORT);
+ stSourceAddr.sin_addr.s_addr = INADDR_ANY;
+
+ /*
+ * Calling bind() is not required, but some implementations need it
+ * before you can reference any multicast socket options
+ * and in this case we must be on port 5353 for ChromeCast to see the packet
+ */
+ nRet = bind(sock, (struct sockaddr *)&stSourceAddr,
+ sizeof(struct sockaddr));
+ if (nRet == SOCKET_ERROR) {
+ DBG((dbgo,"bind failed with %d\n",ERRNO))
+ closesocket(sock);
+ return 1;
+ }
+
+ /* disable loopback of multicast datagrams we send, since the
+ * default--according to Steve Deering--is to loopback all
+ * datagrams sent on any interface which is a member of the
+ * destination group address of that datagram.
+ */
+ nOptVal = 0;
+ nRet = setsockopt (sock, IPPROTO_IP, IP_MULTICAST_LOOP,
+ (char *)&nOptVal, sizeof(int));
+ if (nRet == SOCKET_ERROR) {
+ /* rather than notifying the user, we make note that this option
+ * failed. Some WinSocks don't support this option, and default
+ * with loopback disabled), so this failure is of no consequence.
+ * However, if we *do* get loop-backed data, we'll know why
+ */
+ DBG((dbgo,"[disabling loopback failed with %d]\n",ERRNO))
+ }
+
+#ifdef NEVER // We only want this to be local
+ /* increase the IP TTL from the default of one to 64, so our
+ * multicast datagrams can get off of the local network
+ */
+ nOptVal = 64;
+ nRet = setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL,
+ (char *)&nOptVal, sizeof(int));
+ if (nRet == SOCKET_ERROR) {
+ DBG((dbgo,"increasing TTL failed with %d\n",ERRNO))
+ closesocket(sock);
+ return 1;
+ }
+#endif
+
+ if (psock != NULL)
+ *psock = sock;
+
+ DBG((dbgo,"init sending mDNS succeed\n",ERRNO))
+
+ return 0;
+}
+
+/* Send an mDNS quesry */
+/* on some platforms if we try to transmit & recieve at the same time */
+/* Return nz on error */
+static int send_mDNS(SOCKET sock) {
+ int nRet;
+ int off;
+ ORD8 achOutBuf[BUFSIZE];
+ struct sockaddr_in stDestAddr;
+
+ DBG((dbgo,"send_mDNS() called\n"))
+
+ /* Initialize the Destination Address structure and send */
+ stDestAddr.sin_family = PF_INET;
+ stDestAddr.sin_addr.s_addr = inet_addr(DESTINATION_MCAST);
+ stDestAddr.sin_port = htons(DESTINATION_PORT);
+
+ /* Setup the FQDN data packet to send */
+ write_ORD16_be(0, achOutBuf + 0); /* ID */
+ write_ORD16_be(0, achOutBuf + 2); /* Flags */
+ write_ORD16_be(1, achOutBuf + 4); /* QDCOUNT - one question */
+ write_ORD16_be(0, achOutBuf + 6); /* ANCOUNT */
+ write_ORD16_be(0, achOutBuf + 8); /* NSCOUNT */
+ write_ORD16_be(0, achOutBuf + 10); /* ARCOUNT */
+ off = 12;
+ off = write_string(achOutBuf, off, "_googlecast");
+ off = write_string(achOutBuf, off, "_tcp");
+ off = write_string(achOutBuf, off, "local");
+ write_ORD8(0, achOutBuf + off); /* null string */
+ off += 1;
+ write_ORD16_be(0x000c, achOutBuf + off); /* QCOUNT */
+ off += 2;
+ /* Set top bit to get a unicast response (not for ChromeCast though) */
+ write_ORD16_be(0x0001, achOutBuf + off); /* QCLASS */
+ off += 2;
+
+ nRet = sendto(sock, (char *)achOutBuf, off,
+ 0,
+ (struct sockaddr *) &stDestAddr,
+ sizeof(struct sockaddr));
+ if (nRet == SOCKET_ERROR) {
+ DBG((dbgo,"sending mDNS query failed with %d\n",ERRNO))
+ return 1;
+ }
+
+ DBG((dbgo,"sending mDNS query succeed\n",ERRNO))
+
+ return 0;
+}
+
+static int parse_dns(char **name, char **ip, ORD8 *buf, int size);
+
+/* Free up what get_ccids returned */
+void free_ccids(ccast_id **ids) {
+ if (ids != NULL) {
+ int i;
+
+ for (i = 0; ids[i] != NULL; i++) {
+ free(ids[i]->name);
+ free(ids[i]->ip);
+ free(ids[i]);
+ }
+ free(ids);
+ }
+}
+
+/* Spend the given time waiting for replies. */
+/* (Note than on MSWin this will be a minimum of 500msec) */
+/* Add any ChromeCast replies to the list. */
+/* return nz on error */
+static int init_receive_mDNS(SOCKET *psock) {
+ int nRet;
+ int off, size;
+ struct sockaddr_in stSourceAddr;
+ struct ip_mreq stIpMreq;
+ SOCKET sock;
+
+ DBG((dbgo,"init_receive_mDNS() called\n"))
+
+ /* get a datagram (UDP) socket */
+ sock = socket(PF_INET, SOCK_DGRAM, 0);
+ if (sock == INVALID_SOCKET) {
+ DBG((dbgo,"opening UDP socked failed with %d\n",ERRNO))
+ return 1;
+ }
+
+ /* We can't receive from port 5353 if someone else is using it, */
+ /* so set the SO_REUSEADDR option (which is enough for MSWin), */
+ /* and SO_REUSEPORT for OS X and Linux */
+ {
+ int on = 1, off = 0;
+ if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char *) &on, sizeof(on))) {
+ DBG((dbgo,"setsockopt(SO_REUSEADDR) failed with %d\n",ERRNO))
+ closesocket(sock);
+ return 1;
+ }
+
+ /* Need this to be able to open port on Unix like systems */
+#ifndef NT
+# ifndef SO_REUSEPORT
+# ifdef __APPLE__
+# define SO_REUSEPORT 0x0200
+# else /* Linux */
+# define SO_REUSEPORT 15
+# endif
+# endif
+ if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, (const char *)&on, sizeof(on))) {
+ DBG((dbgo,"setsockopt(SO_REUSEPORT) failed with %d\n",ERRNO))
+ }
+#endif
+ }
+
+ /* init source address structure */
+ stSourceAddr.sin_family = PF_INET;
+ stSourceAddr.sin_port = htons(SOURCE_PORT);
+ stSourceAddr.sin_addr.s_addr = INADDR_ANY;
+
+ /*
+ * Calling bind() is not required, but some implementations need it
+ * before you can reference any multicast socket options
+ * and in this case we must be on port 5353.
+ */
+ nRet = bind(sock, (struct sockaddr *)&stSourceAddr,
+ sizeof(struct sockaddr));
+ if (nRet == SOCKET_ERROR) {
+ DBG((dbgo,"bind failed with %d\n",ERRNO))
+ closesocket(sock);
+ return 1;
+ }
+
+ /* join the multicast group we want to receive datagrams from */
+ stIpMreq.imr_multiaddr.s_addr = inet_addr(DESTINATION_MCAST); /* group addr */
+ stIpMreq.imr_interface.s_addr = INADDR_ANY; /* use default */
+ nRet = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+ (char *)&stIpMreq, sizeof (struct ip_mreq));
+
+ if (nRet == SOCKET_ERROR) {
+ DBG((dbgo,"registering for read events failed with %d\n",ERRNO))
+ closesocket(sock);
+ return 1;
+ }
+
+ /* Make this timeout after 100 msec second */
+#ifdef NT
+ {
+ DWORD tv;
+ tv = 100;
+ if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof(tv)) < 0) {
+ DBG((dbgo,"setsockopt timout failed with %d\n",ERRNO))
+ closesocket(sock);
+ return 1;
+ }
+ }
+#else
+ {
+ struct timeval tv;
+ tv.tv_sec = 0;
+ tv.tv_usec = 100 * 1000;
+ if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof(tv)) < 0) {
+ DBG((dbgo,"setsockopt timout failed with %d\n",ERRNO))
+ closesocket(sock);
+ return 1;
+ }
+ }
+#endif
+
+ if (psock != NULL)
+ *psock = sock;
+
+ return 0;
+}
+
+/* Spend the given time waiting for replies. */
+/* (Note than on MSWin this will be a minimum of 500msec) */
+/* Add any ChromeCast replies to the list. */
+/* return nz on error & free *ids */
+static int receive_mDNS(SOCKET sock, ccast_id ***ids, int emsec) {
+ int nids = 0;
+ unsigned int smsec;
+ unsigned int nSize;
+ int off, size;
+ ORD8 achInBuf[BUFSIZE];
+ struct sockaddr_in stSourceAddr;
+
+ /* Count the number of current id's */
+ if (*ids != NULL) {
+ for (nids = 0; (*ids)[nids] != NULL; nids++)
+ ;
+ }
+
+ DBG((dbgo,"receive_mDNS() called with %d ids\n",nids))
+
+ for (smsec = msec_time(), emsec += smsec;msec_time() <= emsec;) {
+ int i;
+ char *name, *ip;
+ struct sockaddr stSockAddr;
+
+ /* Recv the available data */
+ nSize = sizeof(struct sockaddr);
+ size = recvfrom(sock, (char *)achInBuf,
+ BUFSIZE, 0, (struct sockaddr *) &stSockAddr, &nSize);
+ if (size == SOCKET_ERROR) {
+ if (ERRNO == UDP_SOCKET_TIMEOUT)
+ continue; /* Timeout */
+ DBG((dbgo,"recvfrom failed with %d\n",ERRNO))
+ free_ccids(*ids);
+ *ids = NULL;
+ return 1;
+ }
+ DBG((dbgo,"Got mDNS message length %d bytes\n",size))
+#ifdef DEBUG
+ cc_dump_bytes(dbgo, " ", achInBuf, size);
+#endif
+
+ if (parse_dns(&name, &ip, achInBuf, size) != 0) {
+ DBG((dbgo,"Failed to parse the reply\n"))
+ } else {
+ DBG((dbgo,"Parsed reply OK\n"))
+
+//if (*pnids > 0) {
+// name = strdup("Argyll1234");
+// ip = strdup("10.0.0.129");
+//}
+ /* If we found an entry */
+ if (name != NULL && ip != NULL) {
+ DBG((dbgo,"Got a name '%s' & IP '%s'\n",name,ip))
+ /* Check if it is a duplcate */
+ for (i = 0; i < nids; i++) {
+ if (strcmp((*ids)[i]->name, name) == 0
+ && strcmp((*ids)[i]->ip, ip) == 0)
+ break; /* yes */
+ }
+ if (i < nids) {
+ DBG((dbgo,"Duplicate\n"))
+ free(name);
+ free(ip);
+ } else {
+ ccast_id **tids;
+ if ((tids = realloc(*ids, (nids + 2) * sizeof(ccast_id *))) == NULL
+ || (*ids = tids, (*ids)[nids] = malloc(sizeof(ccast_id)), (*ids)[nids]) == NULL) {
+ DBG((dbgo,"realloc/malloc fail\n"))
+ free(name);
+ free(ip);
+ free_ccids(*ids);
+ *ids = NULL;
+ return 1;
+ } else {
+ DBG((dbgo,"Adding entry\n"))
+ (*ids)[nids]->name = name;
+ (*ids)[nids]->ip = ip;
+ (*ids)[++nids] = NULL; /* End marker */
+ }
+ }
+ }
+ }
+ }
+
+ DBG((dbgo,"receive_mDNS() returning %d in list\n",nids))
+
+ return 0;
+}
+
+/* ==================================================================== */
+
+/* Get a list of Chromecasts. Return NULL on error */
+/* Last pointer in array is NULL */
+/* Takes 0.5 second to return */
+ccast_id **get_ccids() {
+ ccast_id **ids = NULL;
+ int i, j;
+ unsigned int smsec;
+ SOCKET ssock, rsock;
+
+ if (init_mDNS()) {
+ DBG((dbgo,"init_mDNS() failed\n"))
+ return NULL;
+ }
+
+ if (init_send_mDNS(&ssock)) {
+ DBG((dbgo,"init_send_mDNS() failed\n"))
+ return NULL;
+ }
+
+ if (init_receive_mDNS(&rsock)) {
+ DBG((dbgo,"init_receive_mDNS() failed\n"))
+ closesocket(ssock);
+ return NULL;
+ }
+
+ smsec = msec_time();
+
+ DBG((dbgo,"Sending mDNS query:\n"))
+ if (send_mDNS(ssock)) {
+ DBG((dbgo,"send_mDNS() #1 failed\n"))
+ closesocket(ssock);
+ closesocket(rsock);
+ return NULL;
+ }
+
+ if (receive_mDNS(rsock, &ids, 100)) {
+ DBG((dbgo,"receive_mDNS() #1 failed\n"))
+ closesocket(ssock);
+ closesocket(rsock);
+ return NULL;
+ }
+
+ if (ids == NULL && (msec_time() - smsec) < 200) {
+
+ DBG((dbgo,"Sending another mDNS query:\n"))
+ if (send_mDNS(ssock)) {
+ DBG((dbgo,"send_mDNS() #2 failed\n"))
+ closesocket(ssock);
+ closesocket(rsock);
+ return NULL;
+ }
+
+ if (receive_mDNS(rsock, &ids, 500)) {
+ DBG((dbgo,"receive_mDNS() #2 failed\n"))
+ closesocket(ssock);
+ closesocket(rsock);
+ return NULL;
+ }
+ }
+
+ if (ids == NULL) {
+
+ DBG((dbgo,"Sending a final mDNS query:\n"))
+ if (send_mDNS(ssock)) {
+ DBG((dbgo,"send_mDNS() #3 failed\n"))
+ closesocket(ssock);
+ closesocket(rsock);
+ return NULL;
+ }
+
+ if (receive_mDNS(rsock, &ids, 500)) {
+ DBG((dbgo,"receive_mDNS() #3 failed\n"))
+ closesocket(ssock);
+ closesocket(rsock);
+ return NULL;
+ }
+ }
+
+ closesocket(ssock);
+ closesocket(rsock);
+
+ /* If no ChromCasts found, return an empty list */
+ if (ids == NULL) {
+ if ((ids = calloc(sizeof(ccast_id *), 1)) == NULL) {
+ DBG((dbgo,"calloc fail\n"))
+ return NULL;
+ }
+ }
+ /* Sort the results so that it is stable */
+ for (i = 0; ids[i] != NULL && ids[i+1] != NULL; i++) {
+ for (j = i+1; ids[j] != NULL; j++) {
+ if (strcmp(ids[i]->name, ids[j]->name) > 0) {
+ ccast_id *tmp;
+ tmp = ids[i];
+ ids[i] = ids[j];
+ ids[j] = tmp;
+ }
+ }
+ }
+
+ return ids;
+}
+
+void ccast_id_copy(ccast_id *dst, ccast_id *src) {
+ dst->name = strdup(src->name);
+ dst->ip = strdup(src->ip);
+}
+
+ccast_id *ccast_id_clone(ccast_id *src) {
+ ccast_id *dst;
+
+ if ((dst = calloc(sizeof(ccast_id), 1)) == NULL)
+ return dst;
+
+ if (src->name != NULL && (dst->name = strdup(src->name)) == NULL) {
+ free(dst);
+ return NULL;
+ }
+ if (src->ip != NULL && (dst->ip = strdup(src->ip)) == NULL) {
+ free(dst->name);
+ free(dst);
+ return NULL;
+ }
+ return dst;
+}
+
+void ccast_id_del(ccast_id *id) {
+ free(id->name);
+ free(id->ip);
+ free(id);
+}
+
+/* ==================================================================== */
+
+/* Read a string with a trailing '.' added. */
+/* Return the next offset or -1 and *rv = NULL on error */
+static int read_string_imp(char **rv, int *slen, ORD8 *buf, int off, int size, int rec) {
+ int len;
+ int d1 = 0;
+
+//printf("~1 read_string_imp called for off 0x%x rec %d\n",off,rec);
+
+ if (rec > 10) /* Too many recursions */
+ return -1; /* Error */
+
+ if (off >= size)
+ return -1; /* Error */
+
+ for (;;) {
+//printf("~1 top of loop at off 0x%x\n",off);
+ len = buf[off];
+ if (len == 0xc0) { /* Is it an offset marker */
+ int poff;
+//printf("~1 got pointer\n");
+ if ((size - off) < 2)
+ return -1;
+
+ poff = read_ORD16_be(buf + off); off += 2;
+ poff -= 0xc000;
+
+ if (poff < 0 || poff >= size)
+ return -1;
+
+ read_string_imp(rv, slen, buf, poff, size, rec+1);
+//if (slen != NULL) printf("~1 after recurse, slen = %d, off = 0x%x\n",*slen,off);
+
+ break; /* we're done */
+
+ } else {
+//printf("~1 got string length %d\n",len);
+ off++;
+ if ((off + len) >= size)
+ return -1;
+
+ if (len == 0)
+ break; /* we're done */
+
+ if (rv != NULL) {
+ memcpy(*rv, buf + off, len);
+//(*rv)[len] = '\000'; printf("Copied string %p = '%s'\n",*rv,*rv);
+
+ *rv += len;
+ }
+ off += len;
+
+ if (slen != NULL) {
+ (*slen) += len;
+//printf("~1 slen now = %d\n",*slen);
+ }
+
+ }
+ d1 = 1;
+
+ if (slen != NULL)
+ (*slen)++;
+
+ if (rv != NULL) {
+ (*rv)[0] = '.';
+ (*rv)++;
+ }
+ }
+//if (slen != NULL) printf("~1 returning slen = %d\n",*slen);
+ return off;
+}
+
+/* Read a string */
+/* Return the next offset or -1 and *rv = NULL on error */
+static int read_string(char **rv, ORD8 *buf, int off, int size) {
+ int len = 0, toff = off;
+ char *trv;
+
+//printf("~1 read_string called for off 0x%x\n",off);
+
+ /* See how long it will be */
+ if ((toff = read_string_imp(NULL, &len, buf, off, size, 0)) < 0) {
+//printf("~1 read_string_imp length returned error\n");
+ return toff;
+ }
+//printf("~1 read_string_imp got length %d\n",len);
+
+ if (len == 0) {
+//printf("~1 Got zero length string\n");
+ len++; /* Room for null string */
+ }
+ if ((*rv = trv = malloc(len)) == NULL) {
+ return -1;
+ }
+//printf("Malloced %p\n",*rv);
+ off = read_string_imp(&trv, NULL, buf, off, size, 0);
+ if (off >= 0) {
+ (*rv)[len-1] = '\000';
+//printf("~1 read string ok: %p = '%s'\n",*rv, *rv);
+ }
+//else printf("~1 reading string failed\n");
+ return off;
+}
+
+/* Parse an mDNS query */
+/* Return updated off value or -1 on error */
+int parse_query(ORD8 *buf, int off, int size) {
+ char *sv;
+ int qtype, qclass;
+
+ DBG((dbgo,"Parsing query at 0x%x:\n",off))
+ if ((off = read_string(&sv, buf, off, size)) < 0)
+ return -1;
+ DBG((dbgo," Got string '%s'\n",sv))
+ free(sv);
+
+ if ((size - off) < 2)
+ return -1;
+ qtype = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," QTYPE = 0x%04x\n",qtype))
+
+ if ((size - off) < 2)
+ return -1;
+ qclass = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," QCLASS = 0x%04x\n",qtype))
+
+ return off;
+}
+
+/* Parse an mDNS reply */
+/* Return updated off value or -1 on error */
+int parse_reply(char **pname, char **pip, ORD8 *buf, int off, int size) {
+ char *sv;
+ int rtype, rclass, rdlength;
+ unsigned int ttl;
+
+ DBG((dbgo,"Parsing reply at 0x%x:\n",off))
+ if ((off = read_string(&sv, buf, off, size)) < 0)
+ return -1;
+
+ DBG((dbgo," Got string '%s'\n",sv))
+
+ if ((size - off) < 2) {
+ free(sv);
+ return -1;
+ }
+ rtype = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," RTYPE = %d\n",rtype))
+
+ if ((size - off) < 2) {
+ free(sv);
+ return -1;
+ }
+ rclass = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," RCLASS = 0x%04x\n",rclass))
+ /* rclass top bit is cache flush bit */
+
+ if ((rclass & 0x7fff) != DNS_CLASS_IN) {
+ DBG((dbgo," response has RCLASS != 0x%04x\n",DNS_CLASS_IN))
+ free(sv);
+ return -1;
+ }
+
+ if ((size - off) < 4)
+ return -1;
+ ttl = read_ORD32_be(buf + off); off += 4;
+ DBG((dbgo," TTL = %u\n",ttl))
+
+ if ((size - off) < 2)
+ return -1;
+ rdlength = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," RDLENGTH = %d\n",rdlength))
+
+ if ((off + rdlength) > size) {
+ DBG((dbgo," response RDLENGTH is longer than remaining buffer (%d)\n",size - off))
+ free(sv);
+ return -1;
+ }
+
+ /* Just decode the replies we need */
+ if (rtype == DNS_TYPE_TXT) { /* Check it's a ChromeCast & get its name */
+ char *cp;
+ if ((cp = strchr(sv, '.')) == NULL) {
+ free(sv);
+ return -1;
+ }
+ *cp = '\000';
+ if (strcmp(cp+1, "_googlecast._tcp.local") != 0) {
+ DBG((dbgo,"Not a chromecast (got '%s')\n",cp+1))
+ free(sv);
+ return -1;
+ }
+
+ DBG((dbgo," Chromacast '%s'\n", sv))
+ if ((*pname = strdup(sv)) == NULL) {
+ DBG((dbgo,"strdup failed\n"))
+ free(sv);
+ return -1;
+ }
+ } else if (rtype == DNS_TYPE_A) {
+ /* Should we check name matches ? */
+ if ((*pip = malloc(3 * 4 + 3 + 1)) == NULL) {
+ DBG((dbgo,"malloc failed\n"))
+ free(*pname);
+ free(sv);
+ }
+ sprintf(*pip, "%d.%d.%d.%d", buf[off], buf[off+1], buf[off+2], buf[off+3]);
+ DBG((dbgo," V4 address = %s\n",*pip))
+
+ } else if (rtype == DNS_TYPE_AAAA) { /* The IPV6 address */
+ /* Should we check name matches ? */
+ if ((*pip = malloc(8 * 4 + 7 + 1)) == NULL) {
+ DBG((dbgo,"malloc failed\n"))
+ free(*pname);
+ free(sv);
+ }
+ sprintf(*pip, "%x:%x:%x:%x:%x:%x:%x:%x",
+ buf[off+0] * 245 + buf[off+1],
+ buf[off+2] * 245 + buf[off+3],
+ buf[off+4] * 245 + buf[off+5],
+ buf[off+6] * 245 + buf[off+7],
+ buf[off+8] * 245 + buf[off+9],
+ buf[off+10] * 245 + buf[off+11],
+ buf[off+12] * 245 + buf[off+13],
+ buf[off+14] * 245 + buf[off+15]);
+ DBG((dbgo," V6 address = %s\n",*pip))
+
+ } else {
+ DBG((dbgo," Skipping reply at 0x%x\n",off))
+ }
+ off += rdlength;
+ free(sv);
+
+ return off;
+}
+
+/* Parse an mDNS reply into a ChromCast name & IP address */
+/* Allocate and return name and IP on finding ChromeCast reply, NULL otherwise */
+/* Return nz on failure */
+static int parse_dns(char **pname, char **pip, ORD8 *buf, int size) {
+ int i, off = 0;
+ int id, flags, qdcount, ancount, nscount, arcount;
+
+ DBG((dbgo,"Parsing mDNS reply:\n"))
+
+ *pname = NULL;
+ *pip = NULL;
+
+ // Parse reply header
+ if ((size - off) < 2) return 1;
+ id = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," ID = %d\n",id))
+
+ if ((size - off) < 2) return 1;
+ flags = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," FLAGS = 0x%04x\n",flags))
+
+ if ((size - off) < 2) return 1;
+ qdcount = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," QDCOUNT = %d\n",qdcount))
+
+ if ((size - off) < 2) return 1;
+ ancount = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," ANCOUNT = %d\n",ancount))
+
+ if ((size - off) < 2) return 1;
+ nscount = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," NSCOUNT = %d\n",nscount))
+
+ if ((size - off) < 2) return 1;
+ arcount = read_ORD16_be(buf + off); off += 2;
+ DBG((dbgo," ARCOUNT = %d\n",arcount))
+
+//printf("~1 after strings, off = 0x%x\n",off);
+
+ // Parse all the queries (QDCOUNT)
+ for (i = 0; i < qdcount; i++) {
+ if ((off = parse_query(buf, off, size)) < 0) {
+ DBG((dbgo," ### Parsing query failed ###\n"))
+ return 1;
+ }
+ }
+
+ // Parse all the answers (ANCOUNT)
+ for (i = 0; i < ancount; i++) {
+ if ((off = parse_reply(pname, pip, buf, off, size)) < 0) {
+ DBG((dbgo," ### Parsing answer failed ###\n"))
+ return 1;
+ }
+ }
+
+ // Parse all the NS records (NSCOUNT)
+ for (i = 0; i < nscount; i++) {
+ if ((off = parse_reply(pname, pip, buf, off, size)) < 0) {
+ DBG((dbgo," ### Parsing NS record failed ###\n"))
+ return 1;
+ }
+ }
+
+ // Parse all the addition RR answers (ARCOUNT)
+ for (i = 0; i < arcount; i++) {
+ if ((off = parse_reply(pname, pip, buf, off, size)) < 0) {
+ DBG((dbgo," ### Parsing additional records failed ###\n"))
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/*
+ Analysis of ChromeCast reply
+
+ 0000: 00 00 84 00 00 00 00 01 00 00 00 05 0b 5f 67 6f ............._go
+
+ ID 0x0000 // ID 0
+ Flags 0x8400 // Standard query response, No error
+ QDCOUNT 0x0000 // No queries
+ ANCOUNT 0x0001 // 1 Answer
+ NSCOUNT 0x0000
+ ARCOUNT 0x0005 // 5 Additional records
+
+ // Answer
+ 0b 5f 67 6f _go
+ 0010: 6f 67 6c 65 63 61 73 74 oglecast
+
+ 0010: 04 5f 74 63 70 _tcp
+
+ 0010: 05 6c 6f lo
+ 0020: 63 61 6c 00 cal.
+
+ "_googlecast" "_tcp" "cal" "" //TLD
+
+ 0020: 00 0c 00 01 00 00 11 94 00 11 0e 43 ...........C
+
+ RTYPE 0x000c
+ RCLASS 0x0001
+ TTL 0x00001194
+ RDLENGTH 0x0011
+
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+ 0000: 00 00 84 00 00 00 00 01 00 00 00 05 0b 5f 67 6f ............._go
+ 0010: 6f 67 6c 65 63 61 73 74 04 5f 74 63 70 05 6c 6f oglecast._tcp.lo
+ 0020: 63 61 6c 00 00 0c 00 01 00 00 11 94 00 11 0e 43 cal............C
+ 0030: 68 72 6f 6d 65 63 61 73 74 36 38 39 32 c0 0c c0 hromecast6892...
+ 0040: 2e 00 10 80 01 00 00 11 94 00 67 23 69 64 3d 63 ..........g#id=c
+ 0050: 31 37 61 65 38 38 32 65 37 65 31 38 37 35 64 30 17ae882e7e1875d0
+ 0060: 31 33 65 64 32 31 32 63 31 36 62 62 64 34 30 05 13ed212c16bbd40.
+ 0070: 76 65 3d 30 32 0d 6d 64 3d 43 68 72 6f 6d 65 63 ve=02.md=Chromec
+ 0080: 61 73 74 12 69 63 3d 2f 73 65 74 75 70 2f 69 63 ast.ic=/setup/ic
+ 0090: 6f 6e 2e 70 6e 67 11 66 6e 3d 43 68 72 6f 6d 65 on.png.fn=Chrome
+ 00a0: 63 61 73 74 36 38 39 32 04 63 61 3d 35 04 73 74 cast6892.ca=5.st
+ 00b0: 3d 30 c0 2e 00 21 80 01 00 00 00 78 00 17 00 00 =0...!.....x....
+ 00c0: 00 00 1f 49 0e 43 68 72 6f 6d 65 63 61 73 74 36 ...I.Chromecast6
+ 00d0: 38 39 32 c0 1d c0 c4 00 01 80 01 00 00 00 78 00 892...........x.
+ 00e0: 04 0a 00 00 80 c0 2e 00 2f 80 01 00 00 11 94 00 ......../.......
+ 00f0: 09 c0 2e 00 05 00 00 80 00 40 c0 c4 00 2f 80 01 .........@.../..
+ 0100: 00 00 00 78 00 05 c0 c4 00 01 40 ...x......@
+
+
+*/
+
+/* ================================================================== */
+/* Debug */
+
+// Print bytes as hex to stdout
+void cc_dump_bytes(FILE *fp, char *pfx, unsigned char *buf, int len) {
+ int i, j, ii;
+ char oline[200] = { '\000' }, *bp = oline;
+ for (i = j = 0; i < len; i++) {
+ if ((i % 16) == 0)
+ bp += sprintf(bp,"%s%04x:",pfx,i);
+ bp += sprintf(bp," %02x",buf[i]);
+ if ((i+1) >= len || ((i+1) % 16) == 0) {
+ for (ii = i; ((ii+1) % 16) != 0; ii++)
+ bp += sprintf(bp," ");
+ bp += sprintf(bp," ");
+ for (; j <= i; j++) {
+ if (!(buf[j] & 0x80) && isprint(buf[j]))
+ bp += sprintf(bp,"%c",buf[j]);
+ else
+ bp += sprintf(bp,".");
+ }
+ bp += sprintf(bp,"\n");
+ fprintf(fp, "%s", oline);
+ bp = oline;
+ }
+ }
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-20 11:02:04 +0000