1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Copyright (c) 2022 Paulo Alcantara <palcantara@suse.de>
  4 */
  5
  6#ifndef _CIFS_DFS_H
  7#define _CIFS_DFS_H
  8
  9#include "cifsglob.h"
 10#include "cifsproto.h"
 11#include "fs_context.h"
 12#include "dfs_cache.h"
 13#include "cifs_unicode.h"
 14#include <linux/namei.h>
 15
 16#define DFS_INTERLINK(v) \
 17	(((v) & DFSREF_REFERRAL_SERVER) && !((v) & DFSREF_STORAGE_SERVER))
 18
 19struct dfs_ref {
 20	char *path;
 21	char *full_path;
 22	struct cifs_ses *ses;
 23	struct dfs_cache_tgt_list tl;
 24	struct dfs_cache_tgt_iterator *tit;
 25};
 26
 27struct dfs_ref_walk {
 28	struct dfs_ref *ref;
 29	struct dfs_ref refs[MAX_NESTED_LINKS];
 30};
 31
 32#define ref_walk_start(w)	((w)->refs)
 33#define ref_walk_end(w)	(&(w)->refs[ARRAY_SIZE((w)->refs) - 1])
 34#define ref_walk_cur(w)	((w)->ref)
 35#define ref_walk_descend(w)	(--ref_walk_cur(w) >= ref_walk_start(w))
 36
 37#define ref_walk_tit(w)	(ref_walk_cur(w)->tit)
 38#define ref_walk_empty(w)	(!ref_walk_tit(w))
 39#define ref_walk_path(w)	(ref_walk_cur(w)->path)
 40#define ref_walk_fpath(w)	(ref_walk_cur(w)->full_path)
 41#define ref_walk_tl(w)		(&ref_walk_cur(w)->tl)
 42#define ref_walk_ses(w)	(ref_walk_cur(w)->ses)
 43
 44static inline struct dfs_ref_walk *ref_walk_alloc(void)
 45{
 46	struct dfs_ref_walk *rw;
 47
 48	rw = kmalloc(sizeof(*rw), GFP_KERNEL);
 49	if (!rw)
 50		return ERR_PTR(-ENOMEM);
 51	return rw;
 52}
 53
 54static inline void ref_walk_init(struct dfs_ref_walk *rw)
 55{
 56	memset(rw, 0, sizeof(*rw));
 57	ref_walk_cur(rw) = ref_walk_start(rw);
 58}
 59
 60static inline void __ref_walk_free(struct dfs_ref *ref)
 61{
 62	kfree(ref->path);
 63	kfree(ref->full_path);
 64	dfs_cache_free_tgts(&ref->tl);
 65	if (ref->ses)
 66		cifs_put_smb_ses(ref->ses);
 67	memset(ref, 0, sizeof(*ref));
 68}
 69
 70static inline void ref_walk_free(struct dfs_ref_walk *rw)
 71{
 72	struct dfs_ref *ref;
 73
 74	if (!rw)
 75		return;
 76
 77	for (ref = ref_walk_start(rw); ref <= ref_walk_end(rw); ref++)
 78		__ref_walk_free(ref);
 79	kfree(rw);
 80}
 81
 82static inline int ref_walk_advance(struct dfs_ref_walk *rw)
 83{
 84	struct dfs_ref *ref = ref_walk_cur(rw) + 1;
 85
 86	if (ref > ref_walk_end(rw))
 87		return -ELOOP;
 88	__ref_walk_free(ref);
 89	ref_walk_cur(rw) = ref;
 90	return 0;
 91}
 92
 93static inline struct dfs_cache_tgt_iterator *
 94ref_walk_next_tgt(struct dfs_ref_walk *rw)
 95{
 96	struct dfs_cache_tgt_iterator *tit;
 97	struct dfs_ref *ref = ref_walk_cur(rw);
 98
 99	if (!ref->tit)
100		tit = dfs_cache_get_tgt_iterator(&ref->tl);
101	else
102		tit = dfs_cache_get_next_tgt(&ref->tl, ref->tit);
103	ref->tit = tit;
104	return tit;
105}
106
107static inline int ref_walk_get_tgt(struct dfs_ref_walk *rw,
108				   struct dfs_info3_param *tgt)
109{
110	zfree_dfs_info_param(tgt);
111	return dfs_cache_get_tgt_referral(ref_walk_path(rw) + 1,
112					  ref_walk_tit(rw), tgt);
113}
114
115static inline int ref_walk_num_tgts(struct dfs_ref_walk *rw)
116{
117	return dfs_cache_get_nr_tgts(ref_walk_tl(rw));
118}
119
120static inline void ref_walk_set_tgt_hint(struct dfs_ref_walk *rw)
121{
122	dfs_cache_noreq_update_tgthint(ref_walk_path(rw) + 1,
123				       ref_walk_tit(rw));
124}
125
126static inline void ref_walk_set_tcon(struct dfs_ref_walk *rw,
127				     struct cifs_tcon *tcon)
128{
129	struct dfs_ref *ref = ref_walk_start(rw);
130
131	for (; ref <= ref_walk_cur(rw); ref++) {
132		if (WARN_ON_ONCE(!ref->ses))
133			continue;
134		list_add(&ref->ses->dlist, &tcon->dfs_ses_list);
135		ref->ses = NULL;
136	}
137}
138
139int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,
140			      struct smb3_fs_context *ctx);
141int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx);
142
143static inline char *dfs_get_path(struct cifs_sb_info *cifs_sb, const char *path)
144{
145	return dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));
146}
147
148static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx, const char *path,
149				   struct dfs_info3_param *ref, struct dfs_cache_tgt_list *tl)
150{
151	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
152	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
153	struct cifs_ses *rses = ctx->dfs_root_ses ?: mnt_ctx->ses;
154
155	return dfs_cache_find(mnt_ctx->xid, rses, cifs_sb->local_nls,
156			      cifs_remap(cifs_sb), path, ref, tl);
157}
158
159/*
160 * cifs_get_smb_ses() already guarantees an active reference of
161 * @ses->dfs_root_ses when a new session is created, so we need to put extra
162 * references of all DFS root sessions that were used across the mount process
163 * in dfs_mount_share().
164 */
165static inline void dfs_put_root_smb_sessions(struct list_head *head)
166{
167	struct cifs_ses *ses, *n;
168
169	list_for_each_entry_safe(ses, n, head, dlist) {
170		list_del_init(&ses->dlist);
171		cifs_put_smb_ses(ses);
172	}
173}
174
175#endif /* _CIFS_DFS_H */