1 files changed, 198 insertions, 0 deletions
diff --git a/fs/smb/client/dfs.h b/fs/smb/client/dfs.h
new file mode 100644
index 000000000000..e60f0a24a8a1
--- /dev/null
+++ b/fs/smb/client/dfs.h
@@ -0,0 +1,198 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022 Paulo Alcantara <palcantara@suse.de>
+ */
+
+#ifndef _CIFS_DFS_H
+#define _CIFS_DFS_H
+
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "fs_context.h"
+#include "dfs_cache.h"
+#include "cifs_unicode.h"
+#include <linux/namei.h>
+#include <linux/errno.h>
+
+#define DFS_INTERLINK(v) \
+	(((v) & DFSREF_REFERRAL_SERVER) && !((v) & DFSREF_STORAGE_SERVER))
+
+struct dfs_ref {
+	char *path;
+	char *full_path;
+	struct cifs_ses *ses;
+	struct dfs_cache_tgt_list tl;
+	struct dfs_cache_tgt_iterator *tit;
+};
+
+struct dfs_ref_walk {
+	struct cifs_mount_ctx	*mnt_ctx;
+	struct dfs_ref		*ref;
+	struct dfs_ref		refs[MAX_NESTED_LINKS];
+};
+
+#define ref_walk_start(w)	((w)->refs)
+#define ref_walk_end(w)	(&(w)->refs[ARRAY_SIZE((w)->refs) - 1])
+#define ref_walk_cur(w)	((w)->ref)
+#define ref_walk_descend(w)	(--ref_walk_cur(w) >= ref_walk_start(w))
+
+#define ref_walk_tit(w)	(ref_walk_cur(w)->tit)
+#define ref_walk_path(w)	(ref_walk_cur(w)->path)
+#define ref_walk_fpath(w)	(ref_walk_cur(w)->full_path)
+#define ref_walk_tl(w)		(&ref_walk_cur(w)->tl)
+#define ref_walk_ses(w)	(ref_walk_cur(w)->ses)
+
+static inline struct dfs_ref_walk *ref_walk_alloc(void)
+{
+	struct dfs_ref_walk *rw;
+
+	rw = kmalloc(sizeof(*rw), GFP_KERNEL);
+	if (!rw)
+		return ERR_PTR(-ENOMEM);
+	return rw;
+}
+
+static inline void ref_walk_init(struct dfs_ref_walk *rw,
+				 struct cifs_mount_ctx *mnt_ctx)
+{
+	memset(rw, 0, sizeof(*rw));
+	rw->mnt_ctx = mnt_ctx;
+	ref_walk_cur(rw) = ref_walk_start(rw);
+}
+
+static inline void __ref_walk_free(struct dfs_ref *ref)
+{
+	kfree(ref->path);
+	kfree(ref->full_path);
+	dfs_cache_free_tgts(&ref->tl);
+	if (ref->ses)
+		cifs_put_smb_ses(ref->ses);
+	memset(ref, 0, sizeof(*ref));
+}
+
+static inline void ref_walk_free(struct dfs_ref_walk *rw)
+{
+	struct dfs_ref *ref;
+
+	if (!rw)
+		return;
+
+	for (ref = ref_walk_start(rw); ref <= ref_walk_end(rw); ref++)
+		__ref_walk_free(ref);
+	kfree(rw);
+}
+
+static inline int ref_walk_advance(struct dfs_ref_walk *rw)
+{
+	struct dfs_ref *ref = ref_walk_cur(rw) + 1;
+
+	if (ref > ref_walk_end(rw))
+		return -ELOOP;
+	__ref_walk_free(ref);
+	ref_walk_cur(rw) = ref;
+	return 0;
+}
+
+static inline struct dfs_cache_tgt_iterator *
+ref_walk_next_tgt(struct dfs_ref_walk *rw)
+{
+	struct dfs_ref *ref = ref_walk_cur(rw);
+	struct dfs_cache_tgt_iterator *tit;
+
+	if (IS_ERR(ref->tit))
+		return NULL;
+
+	if (!ref->tit)
+		tit = dfs_cache_get_tgt_iterator(&ref->tl);
+	else
+		tit = dfs_cache_get_next_tgt(&ref->tl, ref->tit);
+
+	if (!tit) {
+		ref->tit = ERR_PTR(-ENOENT);
+		return NULL;
+	}
+	ref->tit = tit;
+	return ref->tit;
+}
+
+static inline int ref_walk_get_tgt(struct dfs_ref_walk *rw,
+				   struct dfs_info3_param *tgt)
+{
+	zfree_dfs_info_param(tgt);
+	return dfs_cache_get_tgt_referral(ref_walk_path(rw) + 1,
+					  ref_walk_tit(rw), tgt);
+}
+
+static inline void ref_walk_set_tgt_hint(struct dfs_ref_walk *rw)
+{
+	dfs_cache_noreq_update_tgthint(ref_walk_path(rw) + 1,
+				       ref_walk_tit(rw));
+}
+
+static inline void ref_walk_set_tcon(struct dfs_ref_walk *rw,
+				     struct cifs_tcon *tcon)
+{
+	struct dfs_ref *ref = ref_walk_start(rw);
+
+	for (; ref <= ref_walk_cur(rw); ref++) {
+		if (WARN_ON_ONCE(!ref->ses))
+			continue;
+		list_add(&ref->ses->dlist, &tcon->dfs_ses_list);
+		ref->ses = NULL;
+	}
+}
+
+static inline void ref_walk_mark_end(struct dfs_ref_walk *rw)
+{
+	struct dfs_ref *ref = ref_walk_cur(rw) - 1;
+
+	WARN_ON_ONCE(ref < ref_walk_start(rw));
+	dfs_cache_noreq_update_tgthint(ref->path + 1, ref->tit);
+	ref->tit = ERR_PTR(-ENOENT); /* end marker */
+}
+
+int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,
+			      struct smb3_fs_context *ctx);
+int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx);
+
+static inline char *dfs_get_path(struct cifs_sb_info *cifs_sb, const char *path)
+{
+	return dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));
+}
+
+static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx,
+				   const char *path,
+				   struct dfs_cache_tgt_list *tl)
+{
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct cifs_ses *rses = ctx->dfs_root_ses ?: mnt_ctx->ses;
+
+	return dfs_cache_find(mnt_ctx->xid, rses, cifs_sb->local_nls,
+			      cifs_remap(cifs_sb), path, NULL, tl);
+}
+
+/*
+ * cifs_get_smb_ses() already guarantees an active reference of
+ * @ses->dfs_root_ses when a new session is created, so we need to put extra
+ * references of all DFS root sessions that were used across the mount process
+ * in dfs_mount_share().
+ */
+static inline void dfs_put_root_smb_sessions(struct list_head *head)
+{
+	struct cifs_ses *ses, *n;
+
+	list_for_each_entry_safe(ses, n, head, dlist) {
+		list_del_init(&ses->dlist);
+		cifs_put_smb_ses(ses);
+	}
+}
+
+static inline const char *dfs_ses_refpath(struct cifs_ses *ses)
+{
+	const char *path = ses->server->leaf_fullpath;
+
+	return path ? path + 1 : ERR_PTR(-ENOENT);
+}
+
+#endif /* _CIFS_DFS_H */