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 bofy.
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
68 * uses the space in STUB (which should be an array) as a stub.
72 * uint64_t stub[1024 / 8]; // 1 kB stub properly aligned for 64-bit data.
73 * struct ofpbuf ofpbuf = OFPBUF_STUB_INITIALIZER(stub);
75 #define OFPBUF_STUB_INITIALIZER(STUB) { \
79 .allocated = sizeof (STUB), \
82 .list_node = OVS_LIST_POISON, \
83 .source = OFPBUF_STUB, \
86 void ofpbuf_use_ds(struct ofpbuf *, const struct ds *);
87 void ofpbuf_use_stack(struct ofpbuf *, void *, size_t);
88 void ofpbuf_use_stub(struct ofpbuf *, void *, size_t);
89 void ofpbuf_use_const(struct ofpbuf *, const void *, size_t);
91 void ofpbuf_init(struct ofpbuf *, size_t);
92 void ofpbuf_uninit(struct ofpbuf *);
93 void ofpbuf_reinit(struct ofpbuf *, size_t);
95 struct ofpbuf *ofpbuf_new(size_t);
96 struct ofpbuf *ofpbuf_new_with_headroom(size_t, size_t headroom);
97 struct ofpbuf *ofpbuf_clone(const struct ofpbuf *);
98 struct ofpbuf *ofpbuf_clone_with_headroom(const struct ofpbuf *,
100 struct ofpbuf *ofpbuf_clone_data(const void *, size_t);
101 struct ofpbuf *ofpbuf_clone_data_with_headroom(const void *, size_t,
103 static inline void ofpbuf_delete(struct ofpbuf *);
105 static inline void *ofpbuf_at(const struct ofpbuf *, size_t offset,
107 static inline void *ofpbuf_at_assert(const struct ofpbuf *, size_t offset,
109 static inline void *ofpbuf_tail(const struct ofpbuf *);
110 static inline void *ofpbuf_end(const struct ofpbuf *);
112 void *ofpbuf_put_uninit(struct ofpbuf *, size_t);
113 void *ofpbuf_put_zeros(struct ofpbuf *, size_t);
114 void *ofpbuf_put(struct ofpbuf *, const void *, size_t);
115 char *ofpbuf_put_hex(struct ofpbuf *, const char *s, size_t *n);
116 void ofpbuf_reserve(struct ofpbuf *, size_t);
117 void *ofpbuf_push_uninit(struct ofpbuf *b, size_t);
118 void *ofpbuf_push_zeros(struct ofpbuf *, size_t);
119 void *ofpbuf_push(struct ofpbuf *b, const void *, size_t);
121 static inline size_t ofpbuf_headroom(const struct ofpbuf *);
122 static inline size_t ofpbuf_tailroom(const struct ofpbuf *);
123 static inline size_t ofpbuf_msgsize(const struct ofpbuf *);
124 void ofpbuf_prealloc_headroom(struct ofpbuf *, size_t);
125 void ofpbuf_prealloc_tailroom(struct ofpbuf *, size_t);
126 void ofpbuf_trim(struct ofpbuf *);
127 void ofpbuf_padto(struct ofpbuf *, size_t);
128 void ofpbuf_shift(struct ofpbuf *, int);
130 static inline void ofpbuf_clear(struct ofpbuf *);
131 static inline void *ofpbuf_pull(struct ofpbuf *, size_t);
132 static inline void *ofpbuf_try_pull(struct ofpbuf *, size_t);
134 void *ofpbuf_steal_data(struct ofpbuf *);
136 char *ofpbuf_to_string(const struct ofpbuf *, size_t maxbytes);
137 static inline struct ofpbuf *ofpbuf_from_list(const struct ovs_list *);
138 void ofpbuf_list_delete(struct ovs_list *);
139 static inline bool ofpbuf_equal(const struct ofpbuf *, const struct ofpbuf *);
142 /* Frees memory that 'b' points to, as well as 'b' itself. */
143 static inline void ofpbuf_delete(struct ofpbuf *b)
151 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
152 * byte 'offset'. Otherwise, returns a null pointer. */
153 static inline void *ofpbuf_at(const struct ofpbuf *b, size_t offset,
156 return offset + size <= b->size ? (char *) b->data + offset : NULL;
159 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
160 * 'offset + size' bytes of data. */
161 static inline void *ofpbuf_at_assert(const struct ofpbuf *b, size_t offset,
164 ovs_assert(offset + size <= b->size);
165 return ((char *) b->data) + offset;
168 /* Returns a pointer to byte following the last byte of data in use in 'b'. */
169 static inline void *ofpbuf_tail(const struct ofpbuf *b)
171 return (char *) b->data + b->size;
174 /* Returns a pointer to byte following the last byte allocated for use (but
175 * not necessarily in use) in 'b'. */
176 static inline void *ofpbuf_end(const struct ofpbuf *b)
178 return (char *) b->base + b->allocated;
181 /* Returns the number of bytes of headroom in 'b', that is, the number of bytes
182 * of unused space in ofpbuf 'b' before the data that is in use. (Most
183 * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's
185 static inline size_t ofpbuf_headroom(const struct ofpbuf *b)
187 return (char*)b->data - (char*)b->base;
190 /* Returns the number of bytes that may be appended to the tail end of ofpbuf
191 * 'b' before the ofpbuf must be reallocated. */
192 static inline size_t ofpbuf_tailroom(const struct ofpbuf *b)
194 return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
197 /* Returns the number of bytes from 'b->header' to 'b->msg', that is, the
198 * length of 'b''s header. */
200 ofpbuf_headersize(const struct ofpbuf *b)
202 return (char *)b->msg - (char *)b->header;
205 /* Returns the number of bytes from 'b->msg' to 'b->data + b->size', that is,
206 * the length of the used space in 'b' starting from 'msg'. */
208 ofpbuf_msgsize(const struct ofpbuf *b)
210 return (char *)ofpbuf_tail(b) - (char *)b->msg;
213 /* Clears any data from 'b'. */
214 static inline void ofpbuf_clear(struct ofpbuf *b)
220 /* Removes 'size' bytes from the head end of 'b', which must contain at least
221 * 'size' bytes of data. Returns the first byte of data removed. */
222 static inline void *ofpbuf_pull(struct ofpbuf *b, size_t size)
224 void *data = b->data;
225 b->data = (char*)b->data + size;
226 b->size = b->size - size;
230 /* If 'b' has at least 'size' bytes of data, removes that many bytes from the
231 * head end of 'b' and returns the first byte removed. Otherwise, returns a
232 * null pointer without modifying 'b'. */
233 static inline void *ofpbuf_try_pull(struct ofpbuf *b, size_t size)
235 return b->size >= size ? ofpbuf_pull(b, size) : NULL;
238 static inline struct ofpbuf *ofpbuf_from_list(const struct ovs_list *list)
240 return CONTAINER_OF(list, struct ofpbuf, list_node);
243 static inline bool ofpbuf_equal(const struct ofpbuf *a, const struct ofpbuf *b)
245 return a->size == b->size &&
246 memcmp(a->data, b->data, a->size) == 0;
253 #endif /* ofpbuf.h */