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  
19  struct 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  
27  struct 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  
ref_walk_alloc(void)44  static 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  
ref_walk_init(struct dfs_ref_walk * rw)54  static 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  
__ref_walk_free(struct dfs_ref * ref)60  static 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  
ref_walk_free(struct dfs_ref_walk * rw)70  static 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  
ref_walk_advance(struct dfs_ref_walk * rw)82  static 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  
93  static inline struct dfs_cache_tgt_iterator *
ref_walk_next_tgt(struct dfs_ref_walk * rw)94  ref_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  
ref_walk_get_tgt(struct dfs_ref_walk * rw,struct dfs_info3_param * tgt)107  static 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  
ref_walk_num_tgts(struct dfs_ref_walk * rw)115  static 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  
ref_walk_set_tgt_hint(struct dfs_ref_walk * rw)120  static 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  
ref_walk_set_tcon(struct dfs_ref_walk * rw,struct cifs_tcon * tcon)126  static 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  
139  int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,
140  			      struct smb3_fs_context *ctx);
141  int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx);
142  
dfs_get_path(struct cifs_sb_info * cifs_sb,const char * path)143  static 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  
dfs_get_referral(struct cifs_mount_ctx * mnt_ctx,const char * path,struct dfs_info3_param * ref,struct dfs_cache_tgt_list * tl)148  static 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   */
dfs_put_root_smb_sessions(struct list_head * head)165  static 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 */
176