X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/eecd22ff7b041c6dc3cd5ff517aef64d2b69607c..7c583c73160714a2f61034515adb1a4a32f9d818:/socket.c

diff --git a/socket.c b/socket.c
index 5e037605..0ad8a169 100644
--- a/socket.c
+++ b/socket.c
@@ -18,14 +18,14 @@
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
-/*
-  socket functions used in rsync 
-
-  */
+/**
+ * @file socket.c
+ * 
+ * Socket functions used in rsync.
+ **/
 
 #include "rsync.h"
 
-
 /* Establish a proxy connection on an open socket to a web roxy by
  * using the CONNECT method. */
 static int establish_proxy_connection(int fd, char *host, int port)
@@ -91,20 +91,36 @@ static int establish_proxy_connection(int fd, char *host, int port)
 
 
 
-/* open a socket to a tcp remote host with the specified port 
-   based on code from Warren
-   proxy support by Stephen Rothwell */
-static int open_socket_out (char *host,
-			    int port,
-			    struct in_addr *address)
+/**
+ * Open a socket to a tcp remote host with the specified port .
+ *
+ * Based on code from Warren.  Proxy support by Stephen Rothwell.
+ * getaddrinfo() rewrite contributed by KAME.net.
+ *
+ * Now that we support IPv6 we need to look up the remote machine's
+ * address first, using @p af_hint to set a preference for the type
+ * of address.  Then depending on whether it has v4 or v6 addresses we
+ * try to open a connection.
+ *
+ * The loop allows for machines with some addresses which may not be
+ * reachable, perhaps because we can't e.g. route ipv6 to that network
+ * but we can get ip4 packets through.
+ *
+ * @param bind_address Local address to use.  Normally NULL to bind
+ * the wildcard address.
+ *
+ * @param af_hint Address family, e.g. AF_INET or AF_INET6.
+ **/
+int open_socket_out(char *host, int port, const char *bind_address,
+		    int af_hint)
 {
 	int type = SOCK_STREAM;
-	struct sockaddr_in sock_out;
-	struct sockaddr_in sock;
-	int res;
-	struct hostent *hp;
+	int error;
+	int s;
+	int result;
+	struct addrinfo hints, *res0, *res;
+	char portbuf[10];
 	char *h;
-	unsigned p;
 	int proxied = 0;
 	char buffer[1024];
 	char *cp;
@@ -124,49 +140,79 @@ static int open_socket_out (char *host,
 			return -1;
 		}
 		*cp++ = '\0';
-		p = atoi(cp);
+		strcpy(portbuf, cp);
 		h = buffer;
 	} else {
+		snprintf(portbuf, sizeof(portbuf), "%d", port);
 		h = host;
-		p = port;
-	}
-
-	res = socket(PF_INET, type, 0);
-	if (res == -1) {
-		return -1;
 	}
 
-	hp = gethostbyname(h);
-	if (!hp) {
-		rprintf(FERROR,"unknown host: \"%s\"\n", h);
-		close(res);
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = af_hint;
+	hints.ai_socktype = type;
+	error = getaddrinfo(h, portbuf, &hints, &res0);
+	if (error) {
+		rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
+			h, portbuf, gai_strerror(error));
 		return -1;
 	}
 
-	memcpy(&sock_out.sin_addr, hp->h_addr, hp->h_length);
-	sock_out.sin_port = htons(p);
-	sock_out.sin_family = PF_INET;
+	s = -1;
+	/* Try to connect to all addresses for this machine until we get
+	 * through.  It might e.g. be multi-homed, or have both IPv4 and IPv6
+	 * addresses.  We need to create a socket for each record, since the
+	 * address record tells us what protocol to use to try to connect. */
+	for (res = res0; res; res = res->ai_next) {
+		s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
+		if (s < 0)
+			continue;
 
-	if (address) {
-		sock.sin_addr = *address;
-		sock.sin_port = 0;
-		sock.sin_family = hp->h_addrtype;
-		bind(res, (struct sockaddr * ) &sock,sizeof(sock));
-	}
+		if (bind_address) {
+			struct addrinfo bhints, *bres;
+
+			memset(&bhints, 0, sizeof(bhints));
+			bhints.ai_family = res->ai_family;
+			bhints.ai_socktype = type;
+			bhints.ai_flags = AI_PASSIVE;
+			error = getaddrinfo(bind_address, NULL, &bhints, &bres);
+			if (error) {
+				rprintf(FERROR, RSYNC_NAME ": getaddrinfo: "
+					"bind address %s <noport>: %s\n",
+					bind_address, gai_strerror(error));
+				continue;
+			}
+			if (bres->ai_next) {
+				/* I'm not at all sure that this is the right
+				 * response here... -- mbp */
+				rprintf(FERROR, RSYNC_NAME ": getaddrinfo: "
+					"bind address %s resolved to multiple hosts\n",
+					bind_address);
+				freeaddrinfo(bres);
+				continue;
+			}
+			bind(s, bres->ai_addr, bres->ai_addrlen);
+		}
 
-	if (connect(res,(struct sockaddr *)&sock_out,sizeof(sock_out))) {
-		rprintf (FERROR, RSYNC_NAME ": failed to connect to host %s: %s\n",
-			 h, strerror(errno));
-		close(res);
-		return -1;
+		if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
+			close(s);
+			s = -1;
+			continue;
+		}
+		if (proxied &&
+		    establish_proxy_connection(s, host, port) != 0) {
+			close(s);
+			s = -1;
+			continue;
+		} else
+			break;
 	}
-
-	if (proxied && establish_proxy_connection(res, host, port) != 0) {
-		close(res);
+	freeaddrinfo(res0);
+	if (s < 0) {
+		rprintf(FERROR, RSYNC_NAME ": failed to connect to %s: %s\n",
+			h, strerror(errno));
 		return -1;
 	}
-
-	return res;
+	return s;
 }
 
 
@@ -179,60 +225,106 @@ static int open_socket_out (char *host,
  * cause security problems by really opening remote connections.
  *
  * This is based on the Samba LIBSMB_PROG feature.
+ *
+ * @param bind_address Local address to use.  Normally NULL to get the stack default.
  **/
 int open_socket_out_wrapped (char *host,
 			     int port,
-			     struct in_addr *address)
+			     const char *bind_address,
+			     int af_hint)
 {
 	char *prog;
 
 	if ((prog = getenv ("RSYNC_CONNECT_PROG")) != NULL) 
 		return sock_exec (prog);
 	else 
-		return open_socket_out (host, port, address);
+		return open_socket_out (host, port, bind_address,
+					af_hint);
 }
 
 
 
-/****************************************************************************
-open a socket of the specified type, port and address for incoming data
-****************************************************************************/
-static int open_socket_in(int type, int port, struct in_addr *address)
+/**
+ * Open a socket of the specified type, port and address for incoming data
+ *
+ * Try to be better about handling the results of getaddrinfo(): when
+ * opening an inbound socket, we might get several address results,
+ * e.g. for the machine's ipv4 and ipv6 name.  
+ * 
+ * If binding a wildcard, then any one of them should do.  If an address
+ * was specified but it's insufficiently specific then that's not our
+ * fault.  
+ * 
+ * However, some of the advertized addresses may not work because e.g. we
+ * don't have IPv6 support in the kernel.  In that case go on and try all
+ * addresses until one succeeds.
+ * 
+ * @param bind_address Local address to bind, or NULL to allow it to
+ * default.
+ **/
+static int open_socket_in(int type, int port, const char *bind_address,
+			  int af_hint)
 {
-	struct sockaddr_in sock;
-	int res;
 	int one=1;
-
-	memset((char *)&sock,0,sizeof(sock));
-	sock.sin_port = htons(port);
-	sock.sin_family = AF_INET;
-	if (address) {
-		sock.sin_addr = *address;
-	} else {
-		sock.sin_addr.s_addr = INADDR_ANY;
+	int s;
+	struct addrinfo hints, *res, *resp;
+	char portbuf[10];
+	int error;
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = af_hint;
+	hints.ai_socktype = type;
+	hints.ai_flags = AI_PASSIVE;
+	snprintf(portbuf, sizeof(portbuf), "%d", port);
+	error = getaddrinfo(bind_address, portbuf, &hints, &res);
+	if (error) {
+		rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
+			bind_address, gai_strerror(error));
+		return -1;
 	}
-	res = socket(AF_INET, type, 0);
-	if (res == -1) { 
-		rprintf(FERROR, RSYNC_NAME ": socket failed: %s\n",
-			strerror(errno)); 
-		return -1; 
+	/* XXX: Do we need to care about getting multiple results
+	 * back?  I think probably not; if the user passed
+	 * bind_address == NULL and we set AI_PASSIVE then we ought to
+	 * get a wildcard result. */
+
+	resp = res;
+	while (1) {
+		s = socket(resp->ai_family, resp->ai_socktype, resp->ai_protocol);
+
+		if (s >= 0) {
+			break;	/* got a socket */
+		} else if ((resp = resp->ai_next)) {
+			switch (errno) {
+			case EPROTONOSUPPORT:
+			case EAFNOSUPPORT:
+			case EPFNOSUPPORT:
+			case EINVAL:
+				/* See if there's another address that will work... */
+				continue;
+			}
+		}
+		
+		rprintf(FERROR, RSYNC_NAME ": open inbound socket"
+			"(dom=%d, type=%d, proto=%d) failed: %s\n",
+			resp->ai_family, resp->ai_socktype, resp->ai_protocol,
+			strerror(errno));
+			goto fail;
 	}
 
-	setsockopt(res,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one));
+	setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one));
 
 	/* now we've got a socket - we need to bind it */
-	if (bind(res, (struct sockaddr * ) &sock,sizeof(sock)) == -1) { 
-		rprintf(FERROR,"bind failed on port %d: %s\n", port,
-			strerror(errno));
-		if (errno == EACCES && port < 1024) {
-			rprintf(FERROR, "Note: you must be root to bind "
-				"to low-numbered ports");
-		}
-		close(res); 
-		return -1;
+	if (bind(s, res->ai_addr, res->ai_addrlen) < 0) { 
+		rprintf(FERROR, RSYNC_NAME ": bind failed on port %d\n", port);
+		close(s);
+		goto fail;
 	}
 
-	return res;
+	return s;
+
+fail:
+	freeaddrinfo(res);
+	return -1; 
 }
 
 
@@ -265,10 +357,11 @@ int is_a_socket(int fd)
 void start_accept_loop(int port, int (*fn)(int ))
 {
 	int s;
-	extern struct in_addr socket_address;
+	extern char *bind_address;
 
 	/* open an incoming socket */
-	s = open_socket_in(SOCK_STREAM, port, &socket_address);
+	s = open_socket_in(SOCK_STREAM, port, bind_address,
+			   global_opts.af_hint);
 	if (s == -1)
 		exit_cleanup(RERR_SOCKETIO);
 
@@ -284,8 +377,8 @@ void start_accept_loop(int port, int (*fn)(int ))
 	while (1) {
 		fd_set fds;
 		int fd;
-		struct sockaddr addr;
-		socklen_t in_addrlen = sizeof(addr);
+		struct sockaddr_storage addr;
+		int addrlen = sizeof(addr);
 
 		/* close log file before the potentially very long select so
 		   file can be trimmed by another process instead of growing
@@ -301,8 +394,7 @@ void start_accept_loop(int port, int (*fn)(int ))
 
 		if(!FD_ISSET(s, &fds)) continue;
 
-                /* See note above prototypes. */
-		fd = accept(s,&addr, &in_addrlen);
+		fd = accept(s,(struct sockaddr *)&addr,&addrlen);
 
 		if (fd == -1) continue;
 
@@ -317,11 +409,9 @@ void start_accept_loop(int port, int (*fn)(int ))
 
 		if (fork()==0) {
 			close(s);
-
 			/* open log file in child before possibly giving
 			   up privileges  */
 			log_open();
-
 			_exit(fn(fd));
 		}
 
@@ -465,14 +555,13 @@ void become_daemon(void)
 	}
 }
 
-/*******************************************************************
- return the IP addr of the client as a string 
- ******************************************************************/
+/**
+ * Return the IP addr of the client as a string 
+ **/
 char *client_addr(int fd)
 {
-	struct sockaddr sa;
-	struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
-	socklen_t length = sizeof(sa);
+	struct sockaddr_storage ss;
+	int     length = sizeof(ss);
 	static char addr_buf[100];
 	static int initialised;
 
@@ -480,28 +569,35 @@ char *client_addr(int fd)
 
 	initialised = 1;
 
-	if (getpeername(fd, &sa, &length)) {
+	if (getpeername(fd, (struct sockaddr *)&ss, &length)) {
 		exit_cleanup(RERR_SOCKETIO);
 	}
-	
-	strlcpy(addr_buf,(char *)inet_ntoa(sockin->sin_addr), sizeof(addr_buf));
+
+	getnameinfo((struct sockaddr *)&ss, length,
+		addr_buf, sizeof(addr_buf), NULL, 0, NI_NUMERICHOST);
 	return addr_buf;
 }
 
 
-/*******************************************************************
- return the DNS name of the client 
- ******************************************************************/
+static int get_sockaddr_family(const struct sockaddr_storage *ss)
+{
+	return ((struct sockaddr *) ss)->sa_family;
+}
+
+
+/**
+ * Return the DNS name of the client 
+ **/
 char *client_name(int fd)
 {
-	struct sockaddr sa;
-	struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
-	socklen_t length = sizeof(sa);
+	struct sockaddr_storage ss;
+	int     length = sizeof(ss);
 	static char name_buf[100];
-	struct hostent *hp;
-	char **p;
+	static char port_buf[100];
 	char *def = "UNKNOWN";
 	static int initialised;
+	struct addrinfo hints, *res, *res0;
+	int error;
 
 	if (initialised) return name_buf;
 
@@ -509,101 +605,80 @@ char *client_name(int fd)
 
 	strcpy(name_buf,def);
 
-	if (getpeername(fd, &sa, &length)) {
+	if (getpeername(fd, (struct sockaddr *)&ss, &length)) {
+		/* FIXME: Can we really not continue? */
+		rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n",
+			fd, strerror(errno));
 		exit_cleanup(RERR_SOCKETIO);
 	}
 
-	/* Look up the remote host name. */
-	if ((hp = gethostbyaddr((char *) &sockin->sin_addr,
-				sizeof(sockin->sin_addr),
-				AF_INET))) {
-		strlcpy(name_buf,(char *)hp->h_name,sizeof(name_buf));
-	}
-
-
-	/* do a forward lookup as well to prevent spoofing */
-	hp = gethostbyname(name_buf);
-	if (!hp) {
-		strcpy (name_buf,def);
-		rprintf (FERROR, "reverse name lookup for \"%s\" failed\n",
-			name_buf);
-	} else {
-		for (p=hp->h_addr_list;*p;p++) {
-			if (memcmp(*p, &sockin->sin_addr, hp->h_length) == 0) {
-				break;
-			}
-		}
-		if (!*p) {
-			strcpy(name_buf,def);
-			rprintf(FERROR,"reverse name lookup mismatch - spoofed address?\n");
-		} 
-	}
-
-	return name_buf;
-}
-
-/**
-   Convert a string to an IP address. The string can be a name or
-   dotted decimal number.
+#ifdef INET6
+        if (get_sockaddr_family(&ss) == AF_INET6 && 
+	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&ss)->sin6_addr)) {
+		struct sockaddr_in6 sin6;
+		struct sockaddr_in *sin;
 
-   Returns a pointer to a static in_addr struct -- if you call this
-   more than once then you should copy it.
-*/
-struct in_addr *ip_address(const char *str)
-{
-	static struct in_addr ret;
-	struct hostent *hp;
-
-	if (!str) {
-		rprintf (FERROR, "ip_address received NULL name\n");
-		return NULL;
-	}
-
-	/* try as an IP address */
-	if (inet_aton(str, &ret) != 0) {
-		return &ret;
-	}
-
-	/* otherwise assume it's a network name of some sort and use 
-	   gethostbyname */
-	if ((hp = gethostbyname (str)) == 0) {
-		rprintf(FERROR, "gethostbyname failed for \"%s\": unknown host?\n",str);
-		return NULL;
-	}
+		memcpy(&sin6, &ss, sizeof(sin6));
+		sin = (struct sockaddr_in *)&ss;
+		memset(sin, 0, sizeof(*sin));
+		sin->sin_family = AF_INET;
+		length = sizeof(struct sockaddr_in);
+#ifdef HAVE_SOCKADDR_LEN
+		sin->sin_len = length;
+#endif
+		sin->sin_port = sin6.sin6_port;
+		memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
+			sizeof(sin->sin_addr));
+        }
+#endif
 
-	if (hp->h_addr == NULL) {
-		rprintf(FERROR, "gethostbyname: host address is invalid for host \"%s\"\n",str);
-		return NULL;
+	/* reverse lookup */
+	if (getnameinfo((struct sockaddr *)&ss, length,
+			name_buf, sizeof(name_buf), port_buf, sizeof(port_buf),
+			NI_NAMEREQD | NI_NUMERICSERV) != 0) {
+		strcpy(name_buf, def);
+		rprintf(FERROR, "reverse name lookup failed\n");
+	}
+
+	/* forward lookup */
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = PF_UNSPEC;
+	hints.ai_flags = AI_CANONNAME;
+	hints.ai_socktype = SOCK_STREAM;
+	error = getaddrinfo(name_buf, port_buf, &hints, &res0);
+	if (error) {
+		strcpy(name_buf, def);
+		rprintf(FERROR,
+			RSYNC_NAME ": forward name lookup for %s failed: %s\n",
+			port_buf,
+			gai_strerror(error));
+		return name_buf;
+	}
+
+	/* XXX sin6_flowinfo and other fields */
+	for (res = res0; res; res = res->ai_next) {
+		if (res->ai_family != get_sockaddr_family(&ss))
+			continue;
+		if (res->ai_addrlen != length)
+			continue;
+		if (memcmp(res->ai_addr, &ss, res->ai_addrlen) == 0)
+			break;
 	}
 
-	if (hp->h_length > sizeof ret) {
-		rprintf(FERROR, "gethostbyname: host address for \"%s\" is too large\n",
-			str);
-		return NULL;
-	}
+	/* TODO: Do a  forward lookup as well to prevent spoofing */
 
-	if (hp->h_addrtype != AF_INET) {
-		rprintf (FERROR, "gethostname: host address for \"%s\" is not IPv4\n",
-			 str);
-		return NULL;
+	if (res == NULL) {
+		strcpy(name_buf, def);
+		rprintf(FERROR, RSYNC_NAME ": "
+			"reverse name lookup mismatch on fd%d - spoofed address?\n",
+			fd);
 	}
 
-	/* This is kind of difficult.  The only field in ret is
-	   s_addr, which is the IP address as a 32-bit int.  On
-	   UNICOS, s_addr is in fact a *bitfield* for reasons best
-	   know to Cray.  This means we can't memcpy in to it.  On the
-	   other hand, h_addr is a char*, so we can't just assign.
-
-	   Since there's meant to be only one field inside the in_addr
-	   structure we will try just copying over the top and see how
-	   that goes. */
-	memcpy (&ret, hp->h_addr, hp->h_length);
-
-	return &ret;
+	freeaddrinfo(res0);
+	return name_buf;
 }
 
 
-
 /*******************************************************************
 this is like socketpair but uses tcp. It is used by the Samba
 regression test code