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 dfs_cache_tgt_list tl;
23	struct dfs_cache_tgt_iterator *tit;
24};
25
26struct dfs_ref_walk {
27	struct dfs_ref *ref;
28	struct dfs_ref refs[MAX_NESTED_LINKS];
29};
30
31#define ref_walk_start(w)	((w)->refs)
32#define ref_walk_end(w)	(&(w)->refs[ARRAY_SIZE((w)->refs) - 1])
33#define ref_walk_cur(w)	((w)->ref)
34#define ref_walk_descend(w)	(--ref_walk_cur(w) >= ref_walk_start(w))
35
36#define ref_walk_tit(w)	(ref_walk_cur(w)->tit)
37#define ref_walk_empty(w)	(!ref_walk_tit(w))
38#define ref_walk_path(w)	(ref_walk_cur(w)->path)
39#define ref_walk_fpath(w)	(ref_walk_cur(w)->full_path)
40#define ref_walk_tl(w)		(&ref_walk_cur(w)->tl)
41
42static inline struct dfs_ref_walk *ref_walk_alloc(void)
43{
44	struct dfs_ref_walk *rw;
45
46	rw = kmalloc(sizeof(*rw), GFP_KERNEL);
47	if (!rw)
48		return ERR_PTR(-ENOMEM);
49	return rw;
50}
51
52static inline void ref_walk_init(struct dfs_ref_walk *rw)
53{
54	memset(rw, 0, sizeof(*rw));
55	ref_walk_cur(rw) = ref_walk_start(rw);
56}
57
58static inline void __ref_walk_free(struct dfs_ref *ref)
59{
60	kfree(ref->path);
61	kfree(ref->full_path);
62	dfs_cache_free_tgts(&ref->tl);
63	memset(ref, 0, sizeof(*ref));
64}
65
66static inline void ref_walk_free(struct dfs_ref_walk *rw)
67{
68	struct dfs_ref *ref = ref_walk_start(rw);
69
70	for (; ref <= ref_walk_end(rw); ref++)
71		__ref_walk_free(ref);
72	kfree(rw);
73}
74
75static inline int ref_walk_advance(struct dfs_ref_walk *rw)
76{
77	struct dfs_ref *ref = ref_walk_cur(rw) + 1;
78
79	if (ref > ref_walk_end(rw))
80		return -ELOOP;
81	__ref_walk_free(ref);
82	ref_walk_cur(rw) = ref;
83	return 0;
84}
85
86static inline struct dfs_cache_tgt_iterator *
87ref_walk_next_tgt(struct dfs_ref_walk *rw)
88{
89	struct dfs_cache_tgt_iterator *tit;
90	struct dfs_ref *ref = ref_walk_cur(rw);
91
92	if (!ref->tit)
93		tit = dfs_cache_get_tgt_iterator(&ref->tl);
94	else
95		tit = dfs_cache_get_next_tgt(&ref->tl, ref->tit);
96	ref->tit = tit;
97	return tit;
98}
99
100static inline int ref_walk_get_tgt(struct dfs_ref_walk *rw,
101				   struct dfs_info3_param *tgt)
102{
103	zfree_dfs_info_param(tgt);
104	return dfs_cache_get_tgt_referral(ref_walk_path(rw) + 1,
105					  ref_walk_tit(rw), tgt);
106}
107
108static inline int ref_walk_num_tgts(struct dfs_ref_walk *rw)
109{
110	return dfs_cache_get_nr_tgts(ref_walk_tl(rw));
111}
112
113static inline void ref_walk_set_tgt_hint(struct dfs_ref_walk *rw)
114{
115	dfs_cache_noreq_update_tgthint(ref_walk_path(rw) + 1,
116				       ref_walk_tit(rw));
117}
118
119int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,
120			      struct smb3_fs_context *ctx);
121int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs);
122
123static inline char *dfs_get_path(struct cifs_sb_info *cifs_sb, const char *path)
124{
125	return dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));
126}
127
128static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx, const char *path,
129				   struct dfs_info3_param *ref, struct dfs_cache_tgt_list *tl)
130{
131	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
132	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
133	struct cifs_ses *rses = ctx->dfs_root_ses ?: mnt_ctx->ses;
134
135	return dfs_cache_find(mnt_ctx->xid, rses, cifs_sb->local_nls,
136			      cifs_remap(cifs_sb), path, ref, tl);
137}
138
139/*
140 * cifs_get_smb_ses() already guarantees an active reference of
141 * @ses->dfs_root_ses when a new session is created, so we need to put extra
142 * references of all DFS root sessions that were used across the mount process
143 * in dfs_mount_share().
144 */
145static inline void dfs_put_root_smb_sessions(struct cifs_mount_ctx *mnt_ctx)
146{
147	const struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
148	struct cifs_ses *ses = ctx->dfs_root_ses;
149	struct cifs_ses *cur;
150
151	if (!ses)
152		return;
153
154	for (cur = ses; cur; cur = cur->dfs_root_ses) {
155		if (cur->dfs_root_ses)
156			cifs_put_smb_ses(cur->dfs_root_ses);
157	}
158	cifs_put_smb_ses(ses);
159}
160
161#endif /* _CIFS_DFS_H */
162