2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2015, 2016 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
30 enum OVS_PACKED_ENUM ofpbuf_source {
31 OFPBUF_MALLOC, /* Obtained via malloc(). */
32 OFPBUF_STACK, /* Un-movable stack space or static buffer. */
33 OFPBUF_STUB, /* Starts on stack, may expand into heap. */
36 /* Buffer for holding arbitrary data. An ofpbuf is automatically reallocated
37 * as necessary if it grows too large for the available memory.
39 * 'header' and 'msg' conventions:
41 * OpenFlow messages: 'header' points to the start of the OpenFlow
42 * header, while 'msg' is the OpenFlow msg body.
43 * When parsing, the 'data' will move past these, as data is being
44 * pulled from the OpenFlow message.
46 * Caution: buffer manipulation of 'struct ofpbuf' must always update
47 * the 'header' and 'msg' pointers.
50 * Actions: When encoding OVS action lists, the 'header' is used
51 * as a pointer to the beginning of the current action (see ofpact_put()).
53 * rconn: Reuses 'header' as a private pointer while queuing.
56 void *base; /* First byte of allocated space. */
57 void *data; /* First byte actually in use. */
58 uint32_t size; /* Number of bytes in use. */
59 uint32_t allocated; /* Number of bytes allocated. */
61 void *header; /* OpenFlow header. */
62 void *msg; /* message's body */
63 struct ovs_list list_node; /* Private list element for use by owner. */
64 enum ofpbuf_source source; /* Source of memory allocated as 'base'. */
67 /* An initializer for a struct ofpbuf that will be initially empty and uses the
68 * space in STUB (which should be an array) as a stub. This is the initializer
69 * form of ofpbuf_use_stub().
73 * uint64_t stub[1024 / 8]; // 1 kB stub properly aligned for 64-bit data.
74 * struct ofpbuf ofpbuf = OFPBUF_STUB_INITIALIZER(stub);
76 #define OFPBUF_STUB_INITIALIZER(STUB) { \
80 .allocated = sizeof (STUB), \
83 .list_node = OVS_LIST_POISON, \
84 .source = OFPBUF_STUB, \
87 /* An initializer for a struct ofpbuf whose data starts at DATA and continues
88 * for SIZE bytes. This is appropriate for an ofpbuf that will be used to
89 * inspect existing data, without moving it around or reallocating it, and
90 * generally without modifying it at all. This is the initializer form of
93 static inline struct ofpbuf
94 ofpbuf_const_initializer(const void *data, size_t size)
96 return (struct ofpbuf) {
97 .base = CONST_CAST(void *, data),
98 .data = CONST_CAST(void *, data),
103 .list_node = OVS_LIST_POISON,
104 .source = OFPBUF_STACK,
108 void ofpbuf_use_ds(struct ofpbuf *, const struct ds *);
109 void ofpbuf_use_stack(struct ofpbuf *, void *, size_t);
110 void ofpbuf_use_stub(struct ofpbuf *, void *, size_t);
111 void ofpbuf_use_const(struct ofpbuf *, const void *, size_t);
113 void ofpbuf_init(struct ofpbuf *, size_t);
114 void ofpbuf_uninit(struct ofpbuf *);
115 void ofpbuf_reinit(struct ofpbuf *, size_t);
117 struct ofpbuf *ofpbuf_new(size_t);
118 struct ofpbuf *ofpbuf_new_with_headroom(size_t, size_t headroom);
119 struct ofpbuf *ofpbuf_clone(const struct ofpbuf *);
120 struct ofpbuf *ofpbuf_clone_with_headroom(const struct ofpbuf *,
122 struct ofpbuf *ofpbuf_clone_data(const void *, size_t);
123 struct ofpbuf *ofpbuf_clone_data_with_headroom(const void *, size_t,
125 static inline void ofpbuf_delete(struct ofpbuf *);
127 static inline void *ofpbuf_at(const struct ofpbuf *, size_t offset,
129 static inline void *ofpbuf_at_assert(const struct ofpbuf *, size_t offset,
131 static inline void *ofpbuf_tail(const struct ofpbuf *);
132 static inline void *ofpbuf_end(const struct ofpbuf *);
134 void *ofpbuf_put_uninit(struct ofpbuf *, size_t);
135 void *ofpbuf_put_zeros(struct ofpbuf *, size_t);
136 void *ofpbuf_put(struct ofpbuf *, const void *, size_t);
137 char *ofpbuf_put_hex(struct ofpbuf *, const char *s, size_t *n);
138 void ofpbuf_reserve(struct ofpbuf *, size_t);
139 void *ofpbuf_push_uninit(struct ofpbuf *b, size_t);
140 void *ofpbuf_push_zeros(struct ofpbuf *, size_t);
141 void *ofpbuf_push(struct ofpbuf *b, const void *, size_t);
143 static inline size_t ofpbuf_headroom(const struct ofpbuf *);
144 static inline size_t ofpbuf_tailroom(const struct ofpbuf *);
145 static inline size_t ofpbuf_msgsize(const struct ofpbuf *);
146 void ofpbuf_prealloc_headroom(struct ofpbuf *, size_t);
147 void ofpbuf_prealloc_tailroom(struct ofpbuf *, size_t);
148 void ofpbuf_trim(struct ofpbuf *);
149 void ofpbuf_padto(struct ofpbuf *, size_t);
150 void ofpbuf_shift(struct ofpbuf *, int);
152 static inline void ofpbuf_clear(struct ofpbuf *);
153 static inline void *ofpbuf_pull(struct ofpbuf *, size_t);
154 static inline void *ofpbuf_try_pull(struct ofpbuf *, size_t);
156 void *ofpbuf_steal_data(struct ofpbuf *);
158 char *ofpbuf_to_string(const struct ofpbuf *, size_t maxbytes);
159 static inline struct ofpbuf *ofpbuf_from_list(const struct ovs_list *);
160 void ofpbuf_list_delete(struct ovs_list *);
161 static inline bool ofpbuf_equal(const struct ofpbuf *, const struct ofpbuf *);
164 /* Frees memory that 'b' points to, as well as 'b' itself. */
165 static inline void ofpbuf_delete(struct ofpbuf *b)
173 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
174 * byte 'offset'. Otherwise, returns a null pointer. */
175 static inline void *ofpbuf_at(const struct ofpbuf *b, size_t offset,
178 return offset + size <= b->size ? (char *) b->data + offset : NULL;
181 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
182 * 'offset + size' bytes of data. */
183 static inline void *ofpbuf_at_assert(const struct ofpbuf *b, size_t offset,
186 ovs_assert(offset + size <= b->size);
187 return ((char *) b->data) + offset;
190 /* Returns a pointer to byte following the last byte of data in use in 'b'. */
191 static inline void *ofpbuf_tail(const struct ofpbuf *b)
193 return (char *) b->data + b->size;
196 /* Returns a pointer to byte following the last byte allocated for use (but
197 * not necessarily in use) in 'b'. */
198 static inline void *ofpbuf_end(const struct ofpbuf *b)
200 return (char *) b->base + b->allocated;
203 /* Returns the number of bytes of headroom in 'b', that is, the number of bytes
204 * of unused space in ofpbuf 'b' before the data that is in use. (Most
205 * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's
207 static inline size_t ofpbuf_headroom(const struct ofpbuf *b)
209 return (char*)b->data - (char*)b->base;
212 /* Returns the number of bytes that may be appended to the tail end of ofpbuf
213 * 'b' before the ofpbuf must be reallocated. */
214 static inline size_t ofpbuf_tailroom(const struct ofpbuf *b)
216 return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
219 /* Returns the number of bytes from 'b->header' to 'b->msg', that is, the
220 * length of 'b''s header. */
222 ofpbuf_headersize(const struct ofpbuf *b)
224 return (char *)b->msg - (char *)b->header;
227 /* Returns the number of bytes from 'b->msg' to 'b->data + b->size', that is,
228 * the length of the used space in 'b' starting from 'msg'. */
230 ofpbuf_msgsize(const struct ofpbuf *b)
232 return (char *)ofpbuf_tail(b) - (char *)b->msg;
235 /* Clears any data from 'b'. */
236 static inline void ofpbuf_clear(struct ofpbuf *b)
242 /* Removes 'size' bytes from the head end of 'b', which must contain at least
243 * 'size' bytes of data. Returns the first byte of data removed. */
244 static inline void *ofpbuf_pull(struct ofpbuf *b, size_t size)
246 void *data = b->data;
247 b->data = (char*)b->data + size;
248 b->size = b->size - size;
252 /* If 'b' has at least 'size' bytes of data, removes that many bytes from the
253 * head end of 'b' and returns the first byte removed. Otherwise, returns a
254 * null pointer without modifying 'b'. */
255 static inline void *ofpbuf_try_pull(struct ofpbuf *b, size_t size)
257 return b->size >= size ? ofpbuf_pull(b, size) : NULL;
260 static inline struct ofpbuf *ofpbuf_from_list(const struct ovs_list *list)
262 return CONTAINER_OF(list, struct ofpbuf, list_node);
265 static inline bool ofpbuf_equal(const struct ofpbuf *a, const struct ofpbuf *b)
267 return a->size == b->size &&
268 memcmp(a->data, b->data, a->size) == 0;
275 #endif /* ofpbuf.h */