Move the Client-IP based msdfs target expansion to a VFS module.

Volker

source/modules/vfs_expand_msdfs.c

@@ -0,0 +1,184 @@
+/* 
+ * Expand msdfs targets based on client IP
+ *
+ * Copyright (C) Volker Lendecke, 2004
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *  
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *  
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "includes.h"
+
+#undef DBGC_CLASS
+#define DBGC_CLASS DBGC_VFS
+
+/**********************************************************
+  Under mapfile we expect a table of the following format:
+
+  IP-Prefix whitespace expansion
+
+  For example:
+  192.168.234 local.samba.org
+  192.168     remote.samba.org
+              default.samba.org
+
+  This is to redirect a DFS client to a host close to it.
+***********************************************************/
+
+static BOOL read_target_host(const char *mapfile, pstring targethost)
+{
+	XFILE *f;
+	pstring buf;
+	char *s, *space = buf;
+	BOOL found = False;
+	
+	f = x_fopen(mapfile, O_RDONLY, 0);
+
+	if (f == NULL) {
+		DEBUG(0,("can't open IP map %s. Error %s\n",
+			 mapfile, strerror(errno) ));
+		return False;
+	}
+
+	DEBUG(10, ("Scanning mapfile [%s]\n", mapfile));
+
+	while ((s=fgets_slash(buf, sizeof(buf), f)) != NULL) {
+		space = strchr_m(buf, ' ');
+
+		if (space == NULL) {
+			DEBUG(0, ("Ignoring invalid line %s\n", buf));
+			continue;
+		}
+
+		*space = '\0';
+
+		if (strncmp(client_addr(), buf, strlen(buf)) == 0) {
+			found = True;
+			break;
+		}
+	}
+
+	x_fclose(f);
+
+	if (!found)
+		return False;
+
+	space += 1;
+
+	while (isspace(*space))
+		space += 1;
+
+	pstrcpy(targethost, space);
+	return True;
+}
+
+/**********************************************************
+
+  Expand the msdfs target host using read_target_host
+  explained above. The syntax used in the msdfs link is
+
+  msdfs:@table-filename@/share
+
+  Everything between and including the two @-signs is
+  replaced by the substitution string found in the table
+  described above.
+
+***********************************************************/
+
+static BOOL expand_msdfs_target(connection_struct* conn, pstring target)
+{
+	pstring mapfilename;
+	char *filename_start = strchr_m(target, '@');
+	char *filename_end;
+	int filename_len;
+	pstring targethost;
+	pstring new_target;
+
+	if (filename_start == NULL) {
+		DEBUG(10, ("No filename start in %s\n", target));
+		return False;
+	}
+
+	filename_end = strchr_m(filename_start+1, '@');
+
+	if (filename_end == NULL) {
+		DEBUG(10, ("No filename end in %s\n", target));
+		return False;
+	}
+
+	filename_len = PTR_DIFF(filename_end, filename_start+1);
+	pstrcpy(mapfilename, filename_start+1);
+	mapfilename[filename_len] = '\0';
+
+	DEBUG(10, ("Expanding from table [%s]\n", mapfilename));
+
+	if (!read_target_host(mapfilename, targethost)) {
+		DEBUG(1, ("Could not expand target host from file %s\n",
+			  mapfilename));
+		return False;
+	}
+
+	standard_sub_conn(conn, mapfilename, sizeof(mapfilename));
+
+	DEBUG(10, ("Expanded targethost to %s\n", targethost));
+
+	*filename_start = '\0';
+	pstrcpy(new_target, target);
+	pstrcat(new_target, targethost);
+	pstrcat(new_target, filename_end+1);
+
+	DEBUG(10, ("New DFS target: %s\n", new_target));
+	pstrcpy(target, new_target);
+	return True;
+}
+
+static int expand_msdfs_readlink(struct vfs_handle_struct *handle,
+				 struct connection_struct *conn,
+				 const char *path, char *buf, size_t bufsiz)
+{
+	pstring target;
+	int result;
+
+	result = SMB_VFS_NEXT_READLINK(handle, conn, path, target,
+				       sizeof(target));
+
+	if (result < 0)
+		return result;
+
+	target[result] = '\0';
+
+	if (strchr_m(target, '@') != NULL) {
+		if (!expand_msdfs_target(conn, target)) {
+			errno = ENOENT;
+			return -1;
+		}
+	}
+
+	safe_strcpy(buf, target, bufsiz-1);
+	return strlen(buf);
+}
+
+/* VFS operations structure */
+
+static vfs_op_tuple expand_msdfs_ops[] = {	
+	{SMB_VFS_OP(expand_msdfs_readlink), SMB_VFS_OP_READLINK,
+	 SMB_VFS_LAYER_TRANSPARENT},
+	{SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
+};
+
+NTSTATUS vfs_expand_msdfs_init(void)
+{
+	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "expand_msdfs",
+				expand_msdfs_ops);
+}