1/**
2 * @file
3 * Network buffer management
4 *
5 */
6
7/*
8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without modification,
12 * are permitted provided that the following conditions are met:
13 *
14 * 1. Redistributions of source code must retain the above copyright notice,
15 *    this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright notice,
17 *    this list of conditions and the following disclaimer in the documentation
18 *    and/or other materials provided with the distribution.
19 * 3. The name of the author may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
31 * OF SUCH DAMAGE.
32 *
33 * This file is part of the lwIP TCP/IP stack.
34 *
35 * Author: Adam Dunkels <adam@sics.se>
36 *
37 */
38
39#include "lwip/opt.h"
40
41#if LWIP_NETCONN                /* don't build if not configured for use in lwipopts.h */
42
43#include "lwip/netbuf.h"
44#include "lwip/memp.h"
45
46#include <string.h>
47
48/**
49 * Create (allocate) and initialize a new netbuf.
50 * The netbuf doesn't yet contain a packet buffer!
51 *
52 * @return a pointer to a new netbuf
53 *         NULL on lack of memory
54 */
55struct
56netbuf *netbuf_new(void)
57{
58    struct netbuf *buf;
59
60    buf = memp_malloc(MEMP_NETBUF);
61    if (buf != NULL) {
62        buf->p = NULL;
63        buf->ptr = NULL;
64        buf->addr = NULL;
65        return buf;
66    } else {
67        return NULL;
68    }
69}
70
71/**
72 * Deallocate a netbuf allocated by netbuf_new().
73 *
74 * @param buf pointer to a netbuf allocated by netbuf_new()
75 */
76void netbuf_delete(struct netbuf *buf)
77{
78    if (buf != NULL) {
79        if (buf->p != NULL) {
80            pbuf_free(buf->p);
81            buf->p = buf->ptr = NULL;
82        }
83        memp_free(MEMP_NETBUF, buf);
84    }
85}
86
87/**
88 * Allocate memory for a packet buffer for a given netbuf.
89 *
90 * @param buf the netbuf for which to allocate a packet buffer
91 * @param size the size of the packet buffer to allocate
92 * @return pointer to the allocated memory
93 *         NULL if no memory could be allocated
94 */
95void *netbuf_alloc(struct netbuf *buf, u16_t size)
96{
97    LWIP_ERROR("netbuf_alloc: invalid buf", (buf != NULL), return NULL;
98      );
99
100    /* Deallocate any previously allocated memory. */
101    if (buf->p != NULL) {
102        pbuf_free(buf->p);
103    }
104    buf->p = pbuf_alloc(PBUF_TRANSPORT, size, PBUF_RAM);
105    if (buf->p == NULL) {
106        return NULL;
107    }
108    LWIP_ASSERT("check that first pbuf can hold size", (buf->p->len >= size));
109    buf->ptr = buf->p;
110    return buf->p->payload;
111}
112
113/**
114 * Free the packet buffer included in a netbuf
115 *
116 * @param buf pointer to the netbuf which contains the packet buffer to free
117 */
118void netbuf_free(struct netbuf *buf)
119{
120    LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;
121      );
122    if (buf->p != NULL) {
123        pbuf_free(buf->p);
124    }
125    buf->p = buf->ptr = NULL;
126}
127
128/**
129 * Let a netbuf reference existing (non-volatile) data.
130 *
131 * @param buf netbuf which should reference the data
132 * @param dataptr pointer to the data to reference
133 * @param size size of the data
134 * @return ERR_OK if data is referenced
135 *         ERR_MEM if data couldn't be referenced due to lack of memory
136 */
137err_t netbuf_ref(struct netbuf *buf, const void *dataptr, u16_t size)
138{
139    LWIP_ERROR("netbuf_ref: invalid buf", (buf != NULL), return ERR_ARG;
140      );
141    if (buf->p != NULL) {
142        pbuf_free(buf->p);
143    }
144    buf->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_REF);
145    if (buf->p == NULL) {
146        buf->ptr = NULL;
147        return ERR_MEM;
148    }
149    buf->p->payload = (void *) dataptr;
150    buf->p->len = buf->p->tot_len = size;
151    buf->ptr = buf->p;
152    return ERR_OK;
153}
154
155/**
156 * Chain one netbuf to another (@see pbuf_chain)
157 *
158 * @param head the first netbuf
159 * @param tail netbuf to chain after head, freed by this function, may not be reference after returning
160 */
161void netbuf_chain(struct netbuf *head, struct netbuf *tail)
162{
163    LWIP_ERROR("netbuf_ref: invalid head", (head != NULL), return;
164      );
165    LWIP_ERROR("netbuf_chain: invalid tail", (tail != NULL), return;
166      );
167    pbuf_cat(head->p, tail->p);
168    head->ptr = head->p;
169    memp_free(MEMP_NETBUF, tail);
170}
171
172/**
173 * Get the data pointer and length of the data inside a netbuf.
174 *
175 * @param buf netbuf to get the data from
176 * @param dataptr pointer to a void pointer where to store the data pointer
177 * @param len pointer to an u16_t where the length of the data is stored
178 * @return ERR_OK if the information was retreived,
179 *         ERR_BUF on error.
180 */
181err_t netbuf_data(struct netbuf * buf, void **dataptr, u16_t * len)
182{
183    LWIP_ERROR("netbuf_data: invalid buf", (buf != NULL), return ERR_ARG;
184      );
185    LWIP_ERROR("netbuf_data: invalid dataptr", (dataptr != NULL),
186               return ERR_ARG;
187      );
188    LWIP_ERROR("netbuf_data: invalid len", (len != NULL), return ERR_ARG;
189      );
190
191    if (buf->ptr == NULL) {
192        return ERR_BUF;
193    }
194    *dataptr = buf->ptr->payload;
195    *len = buf->ptr->len;
196    return ERR_OK;
197}
198
199/**
200 * Move the current data pointer of a packet buffer contained in a netbuf
201 * to the next part.
202 * The packet buffer itself is not modified.
203 *
204 * @param buf the netbuf to modify
205 * @return -1 if there is no next part
206 *         1  if moved to the next part but now there is no next part
207 *         0  if moved to the next part and there are still more parts
208 */
209s8_t netbuf_next(struct netbuf * buf)
210{
211    LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return -1;
212      );
213    if (buf->ptr->next == NULL) {
214        return -1;
215    }
216    buf->ptr = buf->ptr->next;
217    if (buf->ptr->next == NULL) {
218        return 1;
219    }
220    return 0;
221}
222
223/**
224 * Move the current data pointer of a packet buffer contained in a netbuf
225 * to the beginning of the packet.
226 * The packet buffer itself is not modified.
227 *
228 * @param buf the netbuf to modify
229 */
230void netbuf_first(struct netbuf *buf)
231{
232    LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;
233      );
234    buf->ptr = buf->p;
235}
236
237#endif                          /* LWIP_NETCONN */
238