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git.ipfire.org Git - thirdparty/squid.git/blob - src/acl/Checklist.h
2 * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
4 * Squid software is distributed under GPLv2+ license and includes
5 * contributions from numerous individuals and organizations.
6 * Please see the COPYING and CONTRIBUTORS files for details.
9 #ifndef SQUID_ACLCHECKLIST_H
10 #define SQUID_ACLCHECKLIST_H
12 #include "acl/InnerNode.h"
16 /// ACL checklist callback
17 typedef void ACLCB(allow_t
, void *);
20 Base class for maintaining Squid and transaction state for access checks.
21 Provides basic ACL checking methods. Its only child, ACLFilledChecklist,
22 keeps the actual state data. The split is necessary to avoid exposing
23 all ACL-related code to virtually Squid data types. */
31 * This abstract class defines the behaviour of
32 * async lookups - which can vary for different ACL types.
33 * Today, every state object must be a singleton.
34 * See NULLState for an example.
36 \note *no* state should be stored in the state object,
37 * they are used to change the behaviour of the checklist, not
38 * to hold information. If you need to store information in the
39 * state object, consider subclassing ACLChecklist, converting it
40 * to a composite, or changing the state objects from singletons to
48 virtual void checkForAsync(ACLChecklist
*) const = 0;
49 virtual ~AsyncState() {}
52 class NullState
: public AsyncState
56 static NullState
*Instance();
57 virtual void checkForAsync(ACLChecklist
*) const;
58 virtual ~NullState() {}
61 static NullState _instance
;
66 virtual ~ACLChecklist();
69 * Start a non-blocking (async) check for a list of allow/deny rules.
70 * Each rule comes with a list of ACLs.
72 * The callback specified will be called with the result of the check.
74 * The first rule where all ACLs match wins. If there is such a rule,
75 * the result becomes that rule keyword (ACCESS_ALLOWED or ACCESS_DENIED).
77 * If there are rules but all ACL lists mismatch, an implicit rule is used.
78 * Its result is the negation of the keyword of the last seen rule.
80 * Some ACLs may stop the check prematurely by setting an exceptional
81 * check result (e.g., ACCESS_AUTH_REQUIRED) instead of declaring a
84 * If there are no rules to check at all, the result becomes ACCESS_DUNNO.
85 * Calling this method with no rules to check wastes a lot of CPU cycles
86 * and will result in a DBG_CRITICAL debugging message.
88 void nonBlockingCheck(ACLCB
* callback
, void *callback_data
);
91 * Perform a blocking (immediate) check for a list of allow/deny rules.
92 * Each rule comes with a list of ACLs.
94 * The first rule where all ACLs match wins. If there is such a rule,
95 * the result becomes that rule keyword (ACCESS_ALLOWED or ACCESS_DENIED).
97 * If there are rules but all ACL lists mismatch, an implicit rule is used
98 * Its result is the negation of the keyword of the last seen rule.
100 * Some ACLs may stop the check prematurely by setting an exceptional
101 * check result (e.g., ACCESS_AUTH_REQUIRED) instead of declaring a
104 * Some ACLs may require an async lookup which is prohibited by this
105 * method. In this case, the exceptional check result of ACCESS_DUNNO is
106 * immediately returned.
108 * If there are no rules to check at all, the result becomes ACCESS_DUNNO.
110 allow_t
const & fastCheck();
113 * Perform a blocking (immediate) check whether a list of ACLs matches.
114 * This method is meant to be used with squid.conf ACL-driven options that
115 * lack allow/deny keywords and are tested one ACL list at a time. Whether
116 * the checks for other occurrences of the same option continue after this
117 * call is up to the caller and option semantics.
119 * If all ACLs match, the result becomes ACCESS_ALLOWED.
121 * If all ACLs mismatch, the result becomes ACCESS_DENIED.
123 * Some ACLs may stop the check prematurely by setting an exceptional
124 * check result (e.g., ACCESS_AUTH_REQUIRED) instead of declaring a
127 * Some ACLs may require an async lookup which is prohibited by this
128 * method. In this case, the exceptional check result of ACCESS_DUNNO is
129 * immediately returned.
131 * If there are no ACLs to check at all, the result becomes ACCESS_ALLOWED.
133 allow_t
const & fastCheck(const Acl::Tree
*list
);
135 /// If slow lookups are allowed, switches into "async in progress" state.
136 /// Otherwise, returns false; the caller is expected to handle the failure.
137 bool goAsync(AsyncState
*);
139 /// Matches (or resumes matching of) a child node while maintaning
140 /// resumption breadcrumbs if a [grand]child node goes async.
141 bool matchChild(const Acl::InnerNode
*parent
, Acl::Nodes::const_iterator pos
, const ACL
*child
);
143 /// Whether we should continue to match tree nodes or stop/pause.
144 bool keepMatching() const { return !finished() && !asyncInProgress(); }
146 /// whether markFinished() was called
147 bool finished() const { return finished_
; }
148 /// async call has been started and has not finished (or failed) yet
149 bool asyncInProgress() const { return asyncStage_
!= asyncNone
; }
150 /// called when no more ACLs should be checked; sets the final answer and
151 /// prints a debugging message explaining the reason for that answer
152 void markFinished(const allow_t
&newAnswer
, const char *reason
);
154 const allow_t
¤tAnswer() const { return allow_
; }
156 /// whether the action is banned or not
157 bool bannedAction(const allow_t
&action
) const;
158 /// add action to the list of banned actions
159 void banAction(const allow_t
&action
);
161 // XXX: ACLs that need request or reply have to use ACLFilledChecklist and
162 // should do their own checks so that we do not have to povide these two
163 // for ACL::checklistMatches to use
164 virtual bool hasRequest() const = 0;
165 virtual bool hasReply() const = 0;
167 /// change the current ACL list
168 /// \return a pointer to the old list value (may be nullptr)
169 const Acl::Tree
*changeAcl(const Acl::Tree
*t
) {
170 const Acl::Tree
*old
= accessList
;
171 if (t
!= accessList
) {
172 cbdataReferenceDone(accessList
);
173 accessList
= cbdataReference(t
);
179 /// Calls non-blocking check callback with the answer and destroys self.
180 void checkCallback(allow_t answer
);
182 void matchAndFinish();
184 void changeState(AsyncState
*);
185 AsyncState
*asyncState() const;
187 const Acl::Tree
*accessList
;
193 /// Resumes non-blocking check started by nonBlockingCheck() and
194 /// suspended until some async operation updated Squid state.
195 void resumeNonBlockingCheck(AsyncState
*state
);
197 private: /* internal methods */
198 /// Position of a child node within an ACL tree.
202 Breadcrumb(): parent(NULL
) {}
203 Breadcrumb(const Acl::InnerNode
*aParent
, Acl::Nodes::const_iterator aPos
): parent(aParent
), position(aPos
) {}
204 bool operator ==(const Breadcrumb
&b
) const { return parent
== b
.parent
&& (!parent
|| position
== b
.position
); }
205 bool operator !=(const Breadcrumb
&b
) const { return !this->operator ==(b
); }
206 void clear() { parent
= NULL
; }
207 const Acl::InnerNode
*parent
; ///< intermediate node in the ACL tree
208 Acl::Nodes::const_iterator position
; ///< child position inside parent
211 /// possible outcomes when trying to match a single ACL node in a list
212 typedef enum { nmrMatch
, nmrMismatch
, nmrFinished
, nmrNeedsAsync
}
215 /// prepare for checking ACLs; called once per check
216 void preCheck(const char *what
);
217 bool prepNonBlocking();
218 void completeNonBlocking();
219 void calcImplicitAnswer();
221 bool asyncCaller_
; ///< whether the caller supports async/slow ACLs
222 bool occupied_
; ///< whether a check (fast or non-blocking) is in progress
226 enum AsyncStage
{ asyncNone
, asyncStarting
, asyncRunning
, asyncFailed
};
227 AsyncStage asyncStage_
;
229 Breadcrumb matchLoc_
; ///< location of the node running matches() now
230 Breadcrumb asyncLoc_
; ///< currentNode_ that called goAsync()
231 unsigned asyncLoopDepth_
; ///< how many times the current async state has resumed
235 /// suspended (due to an async lookup) matches() in the ACL tree
236 std::stack
<Breadcrumb
> matchPath
;
237 /// the list of actions which must ignored during acl checks
238 std::vector
<allow_t
> bannedActions_
;
241 #endif /* SQUID_ACLCHECKLIST_H */