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lwip/core/pbuf.c@0:ac21159e27f4, 2010-07-02 (annotated)

Committer:: darran
Date:: Fri Jul 02 17:21:58 2010 +0000
Revision:: 0:ac21159e27f4

Who changed what in which revision?

User	Revision	Line number	New contents of line
darran	0:ac21159e27f4	1	/**
darran	0:ac21159e27f4	2	* @file
darran	0:ac21159e27f4	3	* Packet buffer management
darran	0:ac21159e27f4	4	*
darran	0:ac21159e27f4	5	* Packets are built from the pbuf data structure. It supports dynamic
darran	0:ac21159e27f4	6	* memory allocation for packet contents or can reference externally
darran	0:ac21159e27f4	7	* managed packet contents both in RAM and ROM. Quick allocation for
darran	0:ac21159e27f4	8	* incoming packets is provided through pools with fixed sized pbufs.
darran	0:ac21159e27f4	9	*
darran	0:ac21159e27f4	10	* A packet may span over multiple pbufs, chained as a singly linked
darran	0:ac21159e27f4	11	* list. This is called a "pbuf chain".
darran	0:ac21159e27f4	12	*
darran	0:ac21159e27f4	13	* Multiple packets may be queued, also using this singly linked list.
darran	0:ac21159e27f4	14	* This is called a "packet queue".
darran	0:ac21159e27f4	15	*
darran	0:ac21159e27f4	16	* So, a packet queue consists of one or more pbuf chains, each of
darran	0:ac21159e27f4	17	* which consist of one or more pbufs. CURRENTLY, PACKET QUEUES ARE
darran	0:ac21159e27f4	18	* NOT SUPPORTED!!! Use helper structs to queue multiple packets.
darran	0:ac21159e27f4	19	*
darran	0:ac21159e27f4	20	* The differences between a pbuf chain and a packet queue are very
darran	0:ac21159e27f4	21	* precise but subtle.
darran	0:ac21159e27f4	22	*
darran	0:ac21159e27f4	23	* The last pbuf of a packet has a ->tot_len field that equals the
darran	0:ac21159e27f4	24	* ->len field. It can be found by traversing the list. If the last
darran	0:ac21159e27f4	25	* pbuf of a packet has a ->next field other than NULL, more packets
darran	0:ac21159e27f4	26	* are on the queue.
darran	0:ac21159e27f4	27	*
darran	0:ac21159e27f4	28	* Therefore, looping through a pbuf of a single packet, has an
darran	0:ac21159e27f4	29	* loop end condition (tot_len == p->len), NOT (next == NULL).
darran	0:ac21159e27f4	30	*/
darran	0:ac21159e27f4	31
darran	0:ac21159e27f4	32	/*
darran	0:ac21159e27f4	33	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
darran	0:ac21159e27f4	34	* All rights reserved.
darran	0:ac21159e27f4	35	*
darran	0:ac21159e27f4	36	* Redistribution and use in source and binary forms, with or without modification,
darran	0:ac21159e27f4	37	* are permitted provided that the following conditions are met:
darran	0:ac21159e27f4	38	*
darran	0:ac21159e27f4	39	* 1. Redistributions of source code must retain the above copyright notice,
darran	0:ac21159e27f4	40	* this list of conditions and the following disclaimer.
darran	0:ac21159e27f4	41	* 2. Redistributions in binary form must reproduce the above copyright notice,
darran	0:ac21159e27f4	42	* this list of conditions and the following disclaimer in the documentation
darran	0:ac21159e27f4	43	* and/or other materials provided with the distribution.
darran	0:ac21159e27f4	44	* 3. The name of the author may not be used to endorse or promote products
darran	0:ac21159e27f4	45	* derived from this software without specific prior written permission.
darran	0:ac21159e27f4	46	*
darran	0:ac21159e27f4	47	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
darran	0:ac21159e27f4	48	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
darran	0:ac21159e27f4	49	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
darran	0:ac21159e27f4	50	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
darran	0:ac21159e27f4	51	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
darran	0:ac21159e27f4	52	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
darran	0:ac21159e27f4	53	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
darran	0:ac21159e27f4	54	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
darran	0:ac21159e27f4	55	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
darran	0:ac21159e27f4	56	* OF SUCH DAMAGE.
darran	0:ac21159e27f4	57	*
darran	0:ac21159e27f4	58	* This file is part of the lwIP TCP/IP stack.
darran	0:ac21159e27f4	59	*
darran	0:ac21159e27f4	60	* Author: Adam Dunkels <adam@sics.se>
darran	0:ac21159e27f4	61	*
darran	0:ac21159e27f4	62	*/
darran	0:ac21159e27f4	63
darran	0:ac21159e27f4	64	#include "lwip/opt.h"
darran	0:ac21159e27f4	65
darran	0:ac21159e27f4	66	#include "lwip/stats.h"
darran	0:ac21159e27f4	67	#include "lwip/def.h"
darran	0:ac21159e27f4	68	#include "lwip/mem.h"
darran	0:ac21159e27f4	69	#include "lwip/memp.h"
darran	0:ac21159e27f4	70	#include "lwip/pbuf.h"
darran	0:ac21159e27f4	71	#include "lwip/sys.h"
darran	0:ac21159e27f4	72	#include "arch/perf.h"
darran	0:ac21159e27f4	73	#if TCP_QUEUE_OOSEQ
darran	0:ac21159e27f4	74	#include "lwip/tcp_impl.h"
darran	0:ac21159e27f4	75	#endif
darran	0:ac21159e27f4	76
darran	0:ac21159e27f4	77	#include <string.h>
darran	0:ac21159e27f4	78
darran	0:ac21159e27f4	79	#define SIZEOF_STRUCT_PBUF LWIP_MEM_ALIGN_SIZE(sizeof(struct pbuf))
darran	0:ac21159e27f4	80	/* Since the pool is created in memp, PBUF_POOL_BUFSIZE will be automatically
darran	0:ac21159e27f4	81	aligned there. Therefore, PBUF_POOL_BUFSIZE_ALIGNED can be used here. */
darran	0:ac21159e27f4	82	#define PBUF_POOL_BUFSIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE)
darran	0:ac21159e27f4	83
darran	0:ac21159e27f4	84	#if !TCP_QUEUE_OOSEQ \|\| NO_SYS
darran	0:ac21159e27f4	85	#define PBUF_POOL_IS_EMPTY()
darran	0:ac21159e27f4	86	#else /* !TCP_QUEUE_OOSEQ \|\| NO_SYS */
darran	0:ac21159e27f4	87	/** Define this to 0 to prevent freeing ooseq pbufs when the PBUF_POOL is empty */
darran	0:ac21159e27f4	88	#ifndef PBUF_POOL_FREE_OOSEQ
darran	0:ac21159e27f4	89	#define PBUF_POOL_FREE_OOSEQ 1
darran	0:ac21159e27f4	90	#endif /* PBUF_POOL_FREE_OOSEQ */
darran	0:ac21159e27f4	91
darran	0:ac21159e27f4	92	#if PBUF_POOL_FREE_OOSEQ
darran	0:ac21159e27f4	93	#include "lwip/tcpip.h"
darran	0:ac21159e27f4	94	#define PBUF_POOL_IS_EMPTY() pbuf_pool_is_empty()
darran	0:ac21159e27f4	95	static u8_t pbuf_free_ooseq_queued;
darran	0:ac21159e27f4	96	/**
darran	0:ac21159e27f4	97	* Attempt to reclaim some memory from queued out-of-sequence TCP segments
darran	0:ac21159e27f4	98	* if we run out of pool pbufs. It's better to give priority to new packets
darran	0:ac21159e27f4	99	* if we're running out.
darran	0:ac21159e27f4	100	*
darran	0:ac21159e27f4	101	* This must be done in the correct thread context therefore this function
darran	0:ac21159e27f4	102	* can only be used with NO_SYS=0 and through tcpip_callback.
darran	0:ac21159e27f4	103	*/
darran	0:ac21159e27f4	104	static void
darran	0:ac21159e27f4	105	pbuf_free_ooseq(void* arg)
darran	0:ac21159e27f4	106	{
darran	0:ac21159e27f4	107	struct tcp_pcb* pcb;
darran	0:ac21159e27f4	108	SYS_ARCH_DECL_PROTECT(old_level);
darran	0:ac21159e27f4	109	LWIP_UNUSED_ARG(arg);
darran	0:ac21159e27f4	110
darran	0:ac21159e27f4	111	SYS_ARCH_PROTECT(old_level);
darran	0:ac21159e27f4	112	pbuf_free_ooseq_queued = 0;
darran	0:ac21159e27f4	113	SYS_ARCH_UNPROTECT(old_level);
darran	0:ac21159e27f4	114
darran	0:ac21159e27f4	115	for (pcb = tcp_active_pcbs; NULL != pcb; pcb = pcb->next) {
darran	0:ac21159e27f4	116	if (NULL != pcb->ooseq) {
darran	0:ac21159e27f4	117	/** Free the ooseq pbufs of one PCB only */
darran	0:ac21159e27f4	118	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_free_ooseq: freeing out-of-sequence pbufs\n"));
darran	0:ac21159e27f4	119	tcp_segs_free(pcb->ooseq);
darran	0:ac21159e27f4	120	pcb->ooseq = NULL;
darran	0:ac21159e27f4	121	return;
darran	0:ac21159e27f4	122	}
darran	0:ac21159e27f4	123	}
darran	0:ac21159e27f4	124	}
darran	0:ac21159e27f4	125
darran	0:ac21159e27f4	126	/** Queue a call to pbuf_free_ooseq if not already queued. */
darran	0:ac21159e27f4	127	static void
darran	0:ac21159e27f4	128	pbuf_pool_is_empty(void)
darran	0:ac21159e27f4	129	{
darran	0:ac21159e27f4	130	u8_t queued;
darran	0:ac21159e27f4	131	SYS_ARCH_DECL_PROTECT(old_level);
darran	0:ac21159e27f4	132
darran	0:ac21159e27f4	133	SYS_ARCH_PROTECT(old_level);
darran	0:ac21159e27f4	134	queued = pbuf_free_ooseq_queued;
darran	0:ac21159e27f4	135	pbuf_free_ooseq_queued = 1;
darran	0:ac21159e27f4	136	SYS_ARCH_UNPROTECT(old_level);
darran	0:ac21159e27f4	137
darran	0:ac21159e27f4	138	if(!queued) {
darran	0:ac21159e27f4	139	/* queue a call to pbuf_free_ooseq if not already queued */
darran	0:ac21159e27f4	140	if(tcpip_callback_with_block(pbuf_free_ooseq, NULL, 0) != ERR_OK) {
darran	0:ac21159e27f4	141	SYS_ARCH_PROTECT(old_level);
darran	0:ac21159e27f4	142	pbuf_free_ooseq_queued = 0;
darran	0:ac21159e27f4	143	SYS_ARCH_UNPROTECT(old_level);
darran	0:ac21159e27f4	144	}
darran	0:ac21159e27f4	145	}
darran	0:ac21159e27f4	146	}
darran	0:ac21159e27f4	147	#endif /* PBUF_POOL_FREE_OOSEQ */
darran	0:ac21159e27f4	148	#endif /* !TCP_QUEUE_OOSEQ \|\| NO_SYS */
darran	0:ac21159e27f4	149
darran	0:ac21159e27f4	150	/**
darran	0:ac21159e27f4	151	* Allocates a pbuf of the given type (possibly a chain for PBUF_POOL type).
darran	0:ac21159e27f4	152	*
darran	0:ac21159e27f4	153	* The actual memory allocated for the pbuf is determined by the
darran	0:ac21159e27f4	154	* layer at which the pbuf is allocated and the requested size
darran	0:ac21159e27f4	155	* (from the size parameter).
darran	0:ac21159e27f4	156	*
darran	0:ac21159e27f4	157	* @param layer flag to define header size
darran	0:ac21159e27f4	158	* @param length size of the pbuf's payload
darran	0:ac21159e27f4	159	* @param type this parameter decides how and where the pbuf
darran	0:ac21159e27f4	160	* should be allocated as follows:
darran	0:ac21159e27f4	161	*
darran	0:ac21159e27f4	162	* - PBUF_RAM: buffer memory for pbuf is allocated as one large
darran	0:ac21159e27f4	163	* chunk. This includes protocol headers as well.
darran	0:ac21159e27f4	164	* - PBUF_ROM: no buffer memory is allocated for the pbuf, even for
darran	0:ac21159e27f4	165	* protocol headers. Additional headers must be prepended
darran	0:ac21159e27f4	166	* by allocating another pbuf and chain in to the front of
darran	0:ac21159e27f4	167	* the ROM pbuf. It is assumed that the memory used is really
darran	0:ac21159e27f4	168	* similar to ROM in that it is immutable and will not be
darran	0:ac21159e27f4	169	* changed. Memory which is dynamic should generally not
darran	0:ac21159e27f4	170	* be attached to PBUF_ROM pbufs. Use PBUF_REF instead.
darran	0:ac21159e27f4	171	* - PBUF_REF: no buffer memory is allocated for the pbuf, even for
darran	0:ac21159e27f4	172	* protocol headers. It is assumed that the pbuf is only
darran	0:ac21159e27f4	173	* being used in a single thread. If the pbuf gets queued,
darran	0:ac21159e27f4	174	* then pbuf_take should be called to copy the buffer.
darran	0:ac21159e27f4	175	* - PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from
darran	0:ac21159e27f4	176	* the pbuf pool that is allocated during pbuf_init().
darran	0:ac21159e27f4	177	*
darran	0:ac21159e27f4	178	* @return the allocated pbuf. If multiple pbufs where allocated, this
darran	0:ac21159e27f4	179	* is the first pbuf of a pbuf chain.
darran	0:ac21159e27f4	180	*/
darran	0:ac21159e27f4	181	struct pbuf *
darran	0:ac21159e27f4	182	pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type)
darran	0:ac21159e27f4	183	{
darran	0:ac21159e27f4	184	struct pbuf p, q, *r;
darran	0:ac21159e27f4	185	u16_t offset;
darran	0:ac21159e27f4	186	s32_t rem_len; /* remaining length */
darran	0:ac21159e27f4	187	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F")\n", length));
darran	0:ac21159e27f4	188
darran	0:ac21159e27f4	189	/* determine header offset */
darran	0:ac21159e27f4	190	offset = 0;
darran	0:ac21159e27f4	191	switch (layer) {
darran	0:ac21159e27f4	192	case PBUF_TRANSPORT:
darran	0:ac21159e27f4	193	/* add room for transport (often TCP) layer header */
darran	0:ac21159e27f4	194	offset += PBUF_TRANSPORT_HLEN;
darran	0:ac21159e27f4	195	/* FALLTHROUGH */
darran	0:ac21159e27f4	196	case PBUF_IP:
darran	0:ac21159e27f4	197	/* add room for IP layer header */
darran	0:ac21159e27f4	198	offset += PBUF_IP_HLEN;
darran	0:ac21159e27f4	199	/* FALLTHROUGH */
darran	0:ac21159e27f4	200	case PBUF_LINK:
darran	0:ac21159e27f4	201	/* add room for link layer header */
darran	0:ac21159e27f4	202	offset += PBUF_LINK_HLEN;
darran	0:ac21159e27f4	203	break;
darran	0:ac21159e27f4	204	case PBUF_RAW:
darran	0:ac21159e27f4	205	break;
darran	0:ac21159e27f4	206	default:
darran	0:ac21159e27f4	207	LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0);
darran	0:ac21159e27f4	208	return NULL;
darran	0:ac21159e27f4	209	}
darran	0:ac21159e27f4	210
darran	0:ac21159e27f4	211	switch (type) {
darran	0:ac21159e27f4	212	case PBUF_POOL:
darran	0:ac21159e27f4	213	/* allocate head of pbuf chain into p */
darran	0:ac21159e27f4	214	p = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
darran	0:ac21159e27f4	215	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_alloc: allocated pbuf %p\n", (void *)p));
darran	0:ac21159e27f4	216	if (p == NULL) {
darran	0:ac21159e27f4	217	PBUF_POOL_IS_EMPTY();
darran	0:ac21159e27f4	218	return NULL;
darran	0:ac21159e27f4	219	}
darran	0:ac21159e27f4	220	p->type = type;
darran	0:ac21159e27f4	221	p->next = NULL;
darran	0:ac21159e27f4	222
darran	0:ac21159e27f4	223	/* make the payload pointer point 'offset' bytes into pbuf data memory */
darran	0:ac21159e27f4	224	p->payload = LWIP_MEM_ALIGN((void )((u8_t )p + (SIZEOF_STRUCT_PBUF + offset)));
darran	0:ac21159e27f4	225	LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned",
darran	0:ac21159e27f4	226	((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
darran	0:ac21159e27f4	227	/* the total length of the pbuf chain is the requested size */
darran	0:ac21159e27f4	228	p->tot_len = length;
darran	0:ac21159e27f4	229	/* set the length of the first pbuf in the chain */
darran	0:ac21159e27f4	230	p->len = LWIP_MIN(length, PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset));
darran	0:ac21159e27f4	231	LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
darran	0:ac21159e27f4	232	((u8_t*)p->payload + p->len <=
darran	0:ac21159e27f4	233	(u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
darran	0:ac21159e27f4	234	LWIP_ASSERT("PBUF_POOL_BUFSIZE must be bigger than MEM_ALIGNMENT",
darran	0:ac21159e27f4	235	(PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)) > 0 );
darran	0:ac21159e27f4	236	/* set reference count (needed here in case we fail) */
darran	0:ac21159e27f4	237	p->ref = 1;
darran	0:ac21159e27f4	238
darran	0:ac21159e27f4	239	/* now allocate the tail of the pbuf chain */
darran	0:ac21159e27f4	240
darran	0:ac21159e27f4	241	/* remember first pbuf for linkage in next iteration */
darran	0:ac21159e27f4	242	r = p;
darran	0:ac21159e27f4	243	/* remaining length to be allocated */
darran	0:ac21159e27f4	244	rem_len = length - p->len;
darran	0:ac21159e27f4	245	/* any remaining pbufs to be allocated? */
darran	0:ac21159e27f4	246	while (rem_len > 0) {
darran	0:ac21159e27f4	247	q = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
darran	0:ac21159e27f4	248	if (q == NULL) {
darran	0:ac21159e27f4	249	PBUF_POOL_IS_EMPTY();
darran	0:ac21159e27f4	250	/* free chain so far allocated */
darran	0:ac21159e27f4	251	pbuf_free(p);
darran	0:ac21159e27f4	252	/* bail out unsuccesfully */
darran	0:ac21159e27f4	253	return NULL;
darran	0:ac21159e27f4	254	}
darran	0:ac21159e27f4	255	q->type = type;
darran	0:ac21159e27f4	256	q->flags = 0;
darran	0:ac21159e27f4	257	q->next = NULL;
darran	0:ac21159e27f4	258	/* make previous pbuf point to this pbuf */
darran	0:ac21159e27f4	259	r->next = q;
darran	0:ac21159e27f4	260	/* set total length of this pbuf and next in chain */
darran	0:ac21159e27f4	261	LWIP_ASSERT("rem_len < max_u16_t", rem_len < 0xffff);
darran	0:ac21159e27f4	262	q->tot_len = (u16_t)rem_len;
darran	0:ac21159e27f4	263	/* this pbuf length is pool size, unless smaller sized tail */
darran	0:ac21159e27f4	264	q->len = LWIP_MIN((u16_t)rem_len, PBUF_POOL_BUFSIZE_ALIGNED);
darran	0:ac21159e27f4	265	q->payload = (void )((u8_t )q + SIZEOF_STRUCT_PBUF);
darran	0:ac21159e27f4	266	LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned",
darran	0:ac21159e27f4	267	((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0);
darran	0:ac21159e27f4	268	LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
darran	0:ac21159e27f4	269	((u8_t*)p->payload + p->len <=
darran	0:ac21159e27f4	270	(u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
darran	0:ac21159e27f4	271	q->ref = 1;
darran	0:ac21159e27f4	272	/* calculate remaining length to be allocated */
darran	0:ac21159e27f4	273	rem_len -= q->len;
darran	0:ac21159e27f4	274	/* remember this pbuf for linkage in next iteration */
darran	0:ac21159e27f4	275	r = q;
darran	0:ac21159e27f4	276	}
darran	0:ac21159e27f4	277	/* end of chain */
darran	0:ac21159e27f4	278	/r->next = NULL;/
darran	0:ac21159e27f4	279
darran	0:ac21159e27f4	280	break;
darran	0:ac21159e27f4	281	case PBUF_RAM:
darran	0:ac21159e27f4	282	/* If pbuf is to be allocated in RAM, allocate memory for it. */
darran	0:ac21159e27f4	283	p = (struct pbuf*)mem_malloc(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length));
darran	0:ac21159e27f4	284	if (p == NULL) {
darran	0:ac21159e27f4	285	return NULL;
darran	0:ac21159e27f4	286	}
darran	0:ac21159e27f4	287	/* Set up internal structure of the pbuf. */
darran	0:ac21159e27f4	288	p->payload = LWIP_MEM_ALIGN((void )((u8_t )p + SIZEOF_STRUCT_PBUF + offset));
darran	0:ac21159e27f4	289	p->len = p->tot_len = length;
darran	0:ac21159e27f4	290	p->next = NULL;
darran	0:ac21159e27f4	291	p->type = type;
darran	0:ac21159e27f4	292
darran	0:ac21159e27f4	293	LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned",
darran	0:ac21159e27f4	294	((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
darran	0:ac21159e27f4	295	break;
darran	0:ac21159e27f4	296	/* pbuf references existing (non-volatile static constant) ROM payload? */
darran	0:ac21159e27f4	297	case PBUF_ROM:
darran	0:ac21159e27f4	298	/* pbuf references existing (externally allocated) RAM payload? */
darran	0:ac21159e27f4	299	case PBUF_REF:
darran	0:ac21159e27f4	300	/* only allocate memory for the pbuf structure */
darran	0:ac21159e27f4	301	p = (struct pbuf *)memp_malloc(MEMP_PBUF);
darran	0:ac21159e27f4	302	if (p == NULL) {
darran	0:ac21159e27f4	303	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_LEVEL_SERIOUS,
darran	0:ac21159e27f4	304	("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n",
darran	0:ac21159e27f4	305	(type == PBUF_ROM) ? "ROM" : "REF"));
darran	0:ac21159e27f4	306	return NULL;
darran	0:ac21159e27f4	307	}
darran	0:ac21159e27f4	308	/* caller must set this field properly, afterwards */
darran	0:ac21159e27f4	309	p->payload = NULL;
darran	0:ac21159e27f4	310	p->len = p->tot_len = length;
darran	0:ac21159e27f4	311	p->next = NULL;
darran	0:ac21159e27f4	312	p->type = type;
darran	0:ac21159e27f4	313	break;
darran	0:ac21159e27f4	314	default:
darran	0:ac21159e27f4	315	LWIP_ASSERT("pbuf_alloc: erroneous type", 0);
darran	0:ac21159e27f4	316	return NULL;
darran	0:ac21159e27f4	317	}
darran	0:ac21159e27f4	318	/* set reference count */
darran	0:ac21159e27f4	319	p->ref = 1;
darran	0:ac21159e27f4	320	/* set flags */
darran	0:ac21159e27f4	321	p->flags = 0;
darran	0:ac21159e27f4	322	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F") == %p\n", length, (void *)p));
darran	0:ac21159e27f4	323	return p;
darran	0:ac21159e27f4	324	}
darran	0:ac21159e27f4	325
darran	0:ac21159e27f4	326
darran	0:ac21159e27f4	327	/**
darran	0:ac21159e27f4	328	* Shrink a pbuf chain to a desired length.
darran	0:ac21159e27f4	329	*
darran	0:ac21159e27f4	330	* @param p pbuf to shrink.
darran	0:ac21159e27f4	331	* @param new_len desired new length of pbuf chain
darran	0:ac21159e27f4	332	*
darran	0:ac21159e27f4	333	* Depending on the desired length, the first few pbufs in a chain might
darran	0:ac21159e27f4	334	* be skipped and left unchanged. The new last pbuf in the chain will be
darran	0:ac21159e27f4	335	* resized, and any remaining pbufs will be freed.
darran	0:ac21159e27f4	336	*
darran	0:ac21159e27f4	337	* @note If the pbuf is ROM/REF, only the ->tot_len and ->len fields are adjusted.
darran	0:ac21159e27f4	338	* @note May not be called on a packet queue.
darran	0:ac21159e27f4	339	*
darran	0:ac21159e27f4	340	* @note Despite its name, pbuf_realloc cannot grow the size of a pbuf (chain).
darran	0:ac21159e27f4	341	*/
darran	0:ac21159e27f4	342	void
darran	0:ac21159e27f4	343	pbuf_realloc(struct pbuf *p, u16_t new_len)
darran	0:ac21159e27f4	344	{
darran	0:ac21159e27f4	345	struct pbuf *q;
darran	0:ac21159e27f4	346	u16_t rem_len; /* remaining length */
darran	0:ac21159e27f4	347	s32_t grow;
darran	0:ac21159e27f4	348
darran	0:ac21159e27f4	349	LWIP_ASSERT("pbuf_realloc: p != NULL", p != NULL);
darran	0:ac21159e27f4	350	LWIP_ASSERT("pbuf_realloc: sane p->type", p->type == PBUF_POOL \|\|
darran	0:ac21159e27f4	351	p->type == PBUF_ROM \|\|
darran	0:ac21159e27f4	352	p->type == PBUF_RAM \|\|
darran	0:ac21159e27f4	353	p->type == PBUF_REF);
darran	0:ac21159e27f4	354
darran	0:ac21159e27f4	355	/* desired length larger than current length? */
darran	0:ac21159e27f4	356	if (new_len >= p->tot_len) {
darran	0:ac21159e27f4	357	/* enlarging not yet supported */
darran	0:ac21159e27f4	358	return;
darran	0:ac21159e27f4	359	}
darran	0:ac21159e27f4	360
darran	0:ac21159e27f4	361	/* the pbuf chain grows by (new_len - p->tot_len) bytes
darran	0:ac21159e27f4	362	* (which may be negative in case of shrinking) */
darran	0:ac21159e27f4	363	grow = new_len - p->tot_len;
darran	0:ac21159e27f4	364
darran	0:ac21159e27f4	365	/* first, step over any pbufs that should remain in the chain */
darran	0:ac21159e27f4	366	rem_len = new_len;
darran	0:ac21159e27f4	367	q = p;
darran	0:ac21159e27f4	368	/* should this pbuf be kept? */
darran	0:ac21159e27f4	369	while (rem_len > q->len) {
darran	0:ac21159e27f4	370	/* decrease remaining length by pbuf length */
darran	0:ac21159e27f4	371	rem_len -= q->len;
darran	0:ac21159e27f4	372	/* decrease total length indicator */
darran	0:ac21159e27f4	373	LWIP_ASSERT("grow < max_u16_t", grow < 0xffff);
darran	0:ac21159e27f4	374	q->tot_len += (u16_t)grow;
darran	0:ac21159e27f4	375	/* proceed to next pbuf in chain */
darran	0:ac21159e27f4	376	q = q->next;
darran	0:ac21159e27f4	377	LWIP_ASSERT("pbuf_realloc: q != NULL", q != NULL);
darran	0:ac21159e27f4	378	}
darran	0:ac21159e27f4	379	/* we have now reached the new last pbuf (in q) */
darran	0:ac21159e27f4	380	/* rem_len == desired length for pbuf q */
darran	0:ac21159e27f4	381
darran	0:ac21159e27f4	382	/* shrink allocated memory for PBUF_RAM */
darran	0:ac21159e27f4	383	/* (other types merely adjust their length fields */
darran	0:ac21159e27f4	384	if ((q->type == PBUF_RAM) && (rem_len != q->len)) {
darran	0:ac21159e27f4	385	/* reallocate and adjust the length of the pbuf that will be split */
darran	0:ac21159e27f4	386	q = (struct pbuf )mem_trim(q, (u16_t)((u8_t )q->payload - (u8_t *)q) + rem_len);
darran	0:ac21159e27f4	387	LWIP_ASSERT("mem_trim returned q == NULL", q != NULL);
darran	0:ac21159e27f4	388	}
darran	0:ac21159e27f4	389	/* adjust length fields for new last pbuf */
darran	0:ac21159e27f4	390	q->len = rem_len;
darran	0:ac21159e27f4	391	q->tot_len = q->len;
darran	0:ac21159e27f4	392
darran	0:ac21159e27f4	393	/* any remaining pbufs in chain? */
darran	0:ac21159e27f4	394	if (q->next != NULL) {
darran	0:ac21159e27f4	395	/* free remaining pbufs in chain */
darran	0:ac21159e27f4	396	pbuf_free(q->next);
darran	0:ac21159e27f4	397	}
darran	0:ac21159e27f4	398	/* q is last packet in chain */
darran	0:ac21159e27f4	399	q->next = NULL;
darran	0:ac21159e27f4	400
darran	0:ac21159e27f4	401	}
darran	0:ac21159e27f4	402
darran	0:ac21159e27f4	403	/**
darran	0:ac21159e27f4	404	* Adjusts the payload pointer to hide or reveal headers in the payload.
darran	0:ac21159e27f4	405	*
darran	0:ac21159e27f4	406	* Adjusts the ->payload pointer so that space for a header
darran	0:ac21159e27f4	407	* (dis)appears in the pbuf payload.
darran	0:ac21159e27f4	408	*
darran	0:ac21159e27f4	409	* The ->payload, ->tot_len and ->len fields are adjusted.
darran	0:ac21159e27f4	410	*
darran	0:ac21159e27f4	411	* @param p pbuf to change the header size.
darran	0:ac21159e27f4	412	* @param header_size_increment Number of bytes to increment header size which
darran	0:ac21159e27f4	413	* increases the size of the pbuf. New space is on the front.
darran	0:ac21159e27f4	414	* (Using a negative value decreases the header size.)
darran	0:ac21159e27f4	415	* If hdr_size_inc is 0, this function does nothing and returns succesful.
darran	0:ac21159e27f4	416	*
darran	0:ac21159e27f4	417	* PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so
darran	0:ac21159e27f4	418	* the call will fail. A check is made that the increase in header size does
darran	0:ac21159e27f4	419	* not move the payload pointer in front of the start of the buffer.
darran	0:ac21159e27f4	420	* @return non-zero on failure, zero on success.
darran	0:ac21159e27f4	421	*
darran	0:ac21159e27f4	422	*/
darran	0:ac21159e27f4	423	u8_t
darran	0:ac21159e27f4	424	pbuf_header(struct pbuf *p, s16_t header_size_increment)
darran	0:ac21159e27f4	425	{
darran	0:ac21159e27f4	426	u16_t type;
darran	0:ac21159e27f4	427	void *payload;
darran	0:ac21159e27f4	428	u16_t increment_magnitude;
darran	0:ac21159e27f4	429
darran	0:ac21159e27f4	430	LWIP_ASSERT("p != NULL", p != NULL);
darran	0:ac21159e27f4	431	if ((header_size_increment == 0) \|\| (p == NULL))
darran	0:ac21159e27f4	432	return 0;
darran	0:ac21159e27f4	433
darran	0:ac21159e27f4	434	if (header_size_increment < 0){
darran	0:ac21159e27f4	435	increment_magnitude = -header_size_increment;
darran	0:ac21159e27f4	436	/* Check that we aren't going to move off the end of the pbuf */
darran	0:ac21159e27f4	437	LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <= p->len), return 1;);
darran	0:ac21159e27f4	438	} else {
darran	0:ac21159e27f4	439	increment_magnitude = header_size_increment;
darran	0:ac21159e27f4	440	#if 0
darran	0:ac21159e27f4	441	/* Can't assert these as some callers speculatively call
darran	0:ac21159e27f4	442	pbuf_header() to see if it's OK. Will return 1 below instead. */
darran	0:ac21159e27f4	443	/* Check that we've got the correct type of pbuf to work with */
darran	0:ac21159e27f4	444	LWIP_ASSERT("p->type == PBUF_RAM \|\| p->type == PBUF_POOL",
darran	0:ac21159e27f4	445	p->type == PBUF_RAM \|\| p->type == PBUF_POOL);
darran	0:ac21159e27f4	446	/* Check that we aren't going to move off the beginning of the pbuf */
darran	0:ac21159e27f4	447	LWIP_ASSERT("p->payload - increment_magnitude >= p + SIZEOF_STRUCT_PBUF",
darran	0:ac21159e27f4	448	(u8_t )p->payload - increment_magnitude >= (u8_t )p + SIZEOF_STRUCT_PBUF);
darran	0:ac21159e27f4	449	#endif
darran	0:ac21159e27f4	450	}
darran	0:ac21159e27f4	451
darran	0:ac21159e27f4	452	type = p->type;
darran	0:ac21159e27f4	453	/* remember current payload pointer */
darran	0:ac21159e27f4	454	payload = p->payload;
darran	0:ac21159e27f4	455
darran	0:ac21159e27f4	456	/* pbuf types containing payloads? */
darran	0:ac21159e27f4	457	if (type == PBUF_RAM \|\| type == PBUF_POOL) {
darran	0:ac21159e27f4	458	/* set new payload pointer */
darran	0:ac21159e27f4	459	p->payload = (u8_t *)p->payload - header_size_increment;
darran	0:ac21159e27f4	460	/* boundary check fails? */
darran	0:ac21159e27f4	461	if ((u8_t )p->payload < (u8_t )p + SIZEOF_STRUCT_PBUF) {
darran	0:ac21159e27f4	462	LWIP_DEBUGF( PBUF_DEBUG \| LWIP_DBG_LEVEL_SERIOUS,
darran	0:ac21159e27f4	463	("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
darran	0:ac21159e27f4	464	(void )p->payload, (void )(p + 1)));
darran	0:ac21159e27f4	465	/* restore old payload pointer */
darran	0:ac21159e27f4	466	p->payload = payload;
darran	0:ac21159e27f4	467	/* bail out unsuccesfully */
darran	0:ac21159e27f4	468	return 1;
darran	0:ac21159e27f4	469	}
darran	0:ac21159e27f4	470	/* pbuf types refering to external payloads? */
darran	0:ac21159e27f4	471	} else if (type == PBUF_REF \|\| type == PBUF_ROM) {
darran	0:ac21159e27f4	472	/* hide a header in the payload? */
darran	0:ac21159e27f4	473	if ((header_size_increment < 0) && (increment_magnitude <= p->len)) {
darran	0:ac21159e27f4	474	/* increase payload pointer */
darran	0:ac21159e27f4	475	p->payload = (u8_t *)p->payload - header_size_increment;
darran	0:ac21159e27f4	476	} else {
darran	0:ac21159e27f4	477	/* cannot expand payload to front (yet!)
darran	0:ac21159e27f4	478	* bail out unsuccesfully */
darran	0:ac21159e27f4	479	return 1;
darran	0:ac21159e27f4	480	}
darran	0:ac21159e27f4	481	}
darran	0:ac21159e27f4	482	else {
darran	0:ac21159e27f4	483	/* Unknown type */
darran	0:ac21159e27f4	484	LWIP_ASSERT("bad pbuf type", 0);
darran	0:ac21159e27f4	485	return 1;
darran	0:ac21159e27f4	486	}
darran	0:ac21159e27f4	487	/* modify pbuf length fields */
darran	0:ac21159e27f4	488	p->len += header_size_increment;
darran	0:ac21159e27f4	489	p->tot_len += header_size_increment;
darran	0:ac21159e27f4	490
darran	0:ac21159e27f4	491	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_header: old %p new %p (%"S16_F")\n",
darran	0:ac21159e27f4	492	(void )payload, (void )p->payload, header_size_increment));
darran	0:ac21159e27f4	493
darran	0:ac21159e27f4	494	return 0;
darran	0:ac21159e27f4	495	}
darran	0:ac21159e27f4	496
darran	0:ac21159e27f4	497	/**
darran	0:ac21159e27f4	498	* Dereference a pbuf chain or queue and deallocate any no-longer-used
darran	0:ac21159e27f4	499	* pbufs at the head of this chain or queue.
darran	0:ac21159e27f4	500	*
darran	0:ac21159e27f4	501	* Decrements the pbuf reference count. If it reaches zero, the pbuf is
darran	0:ac21159e27f4	502	* deallocated.
darran	0:ac21159e27f4	503	*
darran	0:ac21159e27f4	504	* For a pbuf chain, this is repeated for each pbuf in the chain,
darran	0:ac21159e27f4	505	* up to the first pbuf which has a non-zero reference count after
darran	0:ac21159e27f4	506	* decrementing. So, when all reference counts are one, the whole
darran	0:ac21159e27f4	507	* chain is free'd.
darran	0:ac21159e27f4	508	*
darran	0:ac21159e27f4	509	* @param p The pbuf (chain) to be dereferenced.
darran	0:ac21159e27f4	510	*
darran	0:ac21159e27f4	511	* @return the number of pbufs that were de-allocated
darran	0:ac21159e27f4	512	* from the head of the chain.
darran	0:ac21159e27f4	513	*
darran	0:ac21159e27f4	514	* @note MUST NOT be called on a packet queue (Not verified to work yet).
darran	0:ac21159e27f4	515	* @note the reference counter of a pbuf equals the number of pointers
darran	0:ac21159e27f4	516	* that refer to the pbuf (or into the pbuf).
darran	0:ac21159e27f4	517	*
darran	0:ac21159e27f4	518	* @internal examples:
darran	0:ac21159e27f4	519	*
darran	0:ac21159e27f4	520	* Assuming existing chains a->b->c with the following reference
darran	0:ac21159e27f4	521	* counts, calling pbuf_free(a) results in:
darran	0:ac21159e27f4	522	*
darran	0:ac21159e27f4	523	* 1->2->3 becomes ...1->3
darran	0:ac21159e27f4	524	* 3->3->3 becomes 2->3->3
darran	0:ac21159e27f4	525	* 1->1->2 becomes ......1
darran	0:ac21159e27f4	526	* 2->1->1 becomes 1->1->1
darran	0:ac21159e27f4	527	* 1->1->1 becomes .......
darran	0:ac21159e27f4	528	*
darran	0:ac21159e27f4	529	*/
darran	0:ac21159e27f4	530	u8_t
darran	0:ac21159e27f4	531	pbuf_free(struct pbuf *p)
darran	0:ac21159e27f4	532	{
darran	0:ac21159e27f4	533	u16_t type;
darran	0:ac21159e27f4	534	struct pbuf *q;
darran	0:ac21159e27f4	535	u8_t count;
darran	0:ac21159e27f4	536
darran	0:ac21159e27f4	537	if (p == NULL) {
darran	0:ac21159e27f4	538	LWIP_ASSERT("p != NULL", p != NULL);
darran	0:ac21159e27f4	539	/* if assertions are disabled, proceed with debug output */
darran	0:ac21159e27f4	540	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_LEVEL_SERIOUS,
darran	0:ac21159e27f4	541	("pbuf_free(p == NULL) was called.\n"));
darran	0:ac21159e27f4	542	return 0;
darran	0:ac21159e27f4	543	}
darran	0:ac21159e27f4	544	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_free(%p)\n", (void *)p));
darran	0:ac21159e27f4	545
darran	0:ac21159e27f4	546	PERF_START;
darran	0:ac21159e27f4	547
darran	0:ac21159e27f4	548	LWIP_ASSERT("pbuf_free: sane type",
darran	0:ac21159e27f4	549	p->type == PBUF_RAM \|\| p->type == PBUF_ROM \|\|
darran	0:ac21159e27f4	550	p->type == PBUF_REF \|\| p->type == PBUF_POOL);
darran	0:ac21159e27f4	551
darran	0:ac21159e27f4	552	count = 0;
darran	0:ac21159e27f4	553	/* de-allocate all consecutive pbufs from the head of the chain that
darran	0:ac21159e27f4	554	* obtain a zero reference count after decrementing*/
darran	0:ac21159e27f4	555	while (p != NULL) {
darran	0:ac21159e27f4	556	u16_t ref;
darran	0:ac21159e27f4	557	SYS_ARCH_DECL_PROTECT(old_level);
darran	0:ac21159e27f4	558	/* Since decrementing ref cannot be guaranteed to be a single machine operation
darran	0:ac21159e27f4	559	* we must protect it. We put the new ref into a local variable to prevent
darran	0:ac21159e27f4	560	* further protection. */
darran	0:ac21159e27f4	561	SYS_ARCH_PROTECT(old_level);
darran	0:ac21159e27f4	562	/* all pbufs in a chain are referenced at least once */
darran	0:ac21159e27f4	563	LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);
darran	0:ac21159e27f4	564	/* decrease reference count (number of pointers to pbuf) */
darran	0:ac21159e27f4	565	ref = --(p->ref);
darran	0:ac21159e27f4	566	SYS_ARCH_UNPROTECT(old_level);
darran	0:ac21159e27f4	567	/* this pbuf is no longer referenced to? */
darran	0:ac21159e27f4	568	if (ref == 0) {
darran	0:ac21159e27f4	569	/* remember next pbuf in chain for next iteration */
darran	0:ac21159e27f4	570	q = p->next;
darran	0:ac21159e27f4	571	LWIP_DEBUGF( PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_free: deallocating %p\n", (void *)p));
darran	0:ac21159e27f4	572	type = p->type;
darran	0:ac21159e27f4	573	/* is this a pbuf from the pool? */
darran	0:ac21159e27f4	574	if (type == PBUF_POOL) {
darran	0:ac21159e27f4	575	memp_free(MEMP_PBUF_POOL, p);
darran	0:ac21159e27f4	576	/* is this a ROM or RAM referencing pbuf? */
darran	0:ac21159e27f4	577	} else if (type == PBUF_ROM \|\| type == PBUF_REF) {
darran	0:ac21159e27f4	578	memp_free(MEMP_PBUF, p);
darran	0:ac21159e27f4	579	/* type == PBUF_RAM */
darran	0:ac21159e27f4	580	} else {
darran	0:ac21159e27f4	581	mem_free(p);
darran	0:ac21159e27f4	582	}
darran	0:ac21159e27f4	583	count++;
darran	0:ac21159e27f4	584	/* proceed to next pbuf */
darran	0:ac21159e27f4	585	p = q;
darran	0:ac21159e27f4	586	/* p->ref > 0, this pbuf is still referenced to */
darran	0:ac21159e27f4	587	/* (and so the remaining pbufs in chain as well) */
darran	0:ac21159e27f4	588	} else {
darran	0:ac21159e27f4	589	LWIP_DEBUGF( PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, ref));
darran	0:ac21159e27f4	590	/* stop walking through the chain */
darran	0:ac21159e27f4	591	p = NULL;
darran	0:ac21159e27f4	592	}
darran	0:ac21159e27f4	593	}
darran	0:ac21159e27f4	594	PERF_STOP("pbuf_free");
darran	0:ac21159e27f4	595	/* return number of de-allocated pbufs */
darran	0:ac21159e27f4	596	return count;
darran	0:ac21159e27f4	597	}
darran	0:ac21159e27f4	598
darran	0:ac21159e27f4	599	/**
darran	0:ac21159e27f4	600	* Count number of pbufs in a chain
darran	0:ac21159e27f4	601	*
darran	0:ac21159e27f4	602	* @param p first pbuf of chain
darran	0:ac21159e27f4	603	* @return the number of pbufs in a chain
darran	0:ac21159e27f4	604	*/
darran	0:ac21159e27f4	605
darran	0:ac21159e27f4	606	u8_t
darran	0:ac21159e27f4	607	pbuf_clen(struct pbuf *p)
darran	0:ac21159e27f4	608	{
darran	0:ac21159e27f4	609	u8_t len;
darran	0:ac21159e27f4	610
darran	0:ac21159e27f4	611	len = 0;
darran	0:ac21159e27f4	612	while (p != NULL) {
darran	0:ac21159e27f4	613	++len;
darran	0:ac21159e27f4	614	p = p->next;
darran	0:ac21159e27f4	615	}
darran	0:ac21159e27f4	616	return len;
darran	0:ac21159e27f4	617	}
darran	0:ac21159e27f4	618
darran	0:ac21159e27f4	619	/**
darran	0:ac21159e27f4	620	* Increment the reference count of the pbuf.
darran	0:ac21159e27f4	621	*
darran	0:ac21159e27f4	622	* @param p pbuf to increase reference counter of
darran	0:ac21159e27f4	623	*
darran	0:ac21159e27f4	624	*/
darran	0:ac21159e27f4	625	void
darran	0:ac21159e27f4	626	pbuf_ref(struct pbuf *p)
darran	0:ac21159e27f4	627	{
darran	0:ac21159e27f4	628	SYS_ARCH_DECL_PROTECT(old_level);
darran	0:ac21159e27f4	629	/* pbuf given? */
darran	0:ac21159e27f4	630	if (p != NULL) {
darran	0:ac21159e27f4	631	SYS_ARCH_PROTECT(old_level);
darran	0:ac21159e27f4	632	++(p->ref);
darran	0:ac21159e27f4	633	SYS_ARCH_UNPROTECT(old_level);
darran	0:ac21159e27f4	634	}
darran	0:ac21159e27f4	635	}
darran	0:ac21159e27f4	636
darran	0:ac21159e27f4	637	/**
darran	0:ac21159e27f4	638	* Concatenate two pbufs (each may be a pbuf chain) and take over
darran	0:ac21159e27f4	639	* the caller's reference of the tail pbuf.
darran	0:ac21159e27f4	640	*
darran	0:ac21159e27f4	641	* @note The caller MAY NOT reference the tail pbuf afterwards.
darran	0:ac21159e27f4	642	* Use pbuf_chain() for that purpose.
darran	0:ac21159e27f4	643	*
darran	0:ac21159e27f4	644	* @see pbuf_chain()
darran	0:ac21159e27f4	645	*/
darran	0:ac21159e27f4	646
darran	0:ac21159e27f4	647	void
darran	0:ac21159e27f4	648	pbuf_cat(struct pbuf h, struct pbuf t)
darran	0:ac21159e27f4	649	{
darran	0:ac21159e27f4	650	struct pbuf *p;
darran	0:ac21159e27f4	651
darran	0:ac21159e27f4	652	LWIP_ERROR("(h != NULL) && (t != NULL) (programmer violates API)",
darran	0:ac21159e27f4	653	((h != NULL) && (t != NULL)), return;);
darran	0:ac21159e27f4	654
darran	0:ac21159e27f4	655	/* proceed to last pbuf of chain */
darran	0:ac21159e27f4	656	for (p = h; p->next != NULL; p = p->next) {
darran	0:ac21159e27f4	657	/* add total length of second chain to all totals of first chain */
darran	0:ac21159e27f4	658	p->tot_len += t->tot_len;
darran	0:ac21159e27f4	659	}
darran	0:ac21159e27f4	660	/* { p is last pbuf of first h chain, p->next == NULL } */
darran	0:ac21159e27f4	661	LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len);
darran	0:ac21159e27f4	662	LWIP_ASSERT("p->next == NULL", p->next == NULL);
darran	0:ac21159e27f4	663	/* add total length of second chain to last pbuf total of first chain */
darran	0:ac21159e27f4	664	p->tot_len += t->tot_len;
darran	0:ac21159e27f4	665	/* chain last pbuf of head (p) with first of tail (t) */
darran	0:ac21159e27f4	666	p->next = t;
darran	0:ac21159e27f4	667	/* p->next now references t, but the caller will drop its reference to t,
darran	0:ac21159e27f4	668	* so netto there is no change to the reference count of t.
darran	0:ac21159e27f4	669	*/
darran	0:ac21159e27f4	670	}
darran	0:ac21159e27f4	671
darran	0:ac21159e27f4	672	/**
darran	0:ac21159e27f4	673	* Chain two pbufs (or pbuf chains) together.
darran	0:ac21159e27f4	674	*
darran	0:ac21159e27f4	675	* The caller MUST call pbuf_free(t) once it has stopped
darran	0:ac21159e27f4	676	* using it. Use pbuf_cat() instead if you no longer use t.
darran	0:ac21159e27f4	677	*
darran	0:ac21159e27f4	678	* @param h head pbuf (chain)
darran	0:ac21159e27f4	679	* @param t tail pbuf (chain)
darran	0:ac21159e27f4	680	* @note The pbufs MUST belong to the same packet.
darran	0:ac21159e27f4	681	* @note MAY NOT be called on a packet queue.
darran	0:ac21159e27f4	682	*
darran	0:ac21159e27f4	683	* The ->tot_len fields of all pbufs of the head chain are adjusted.
darran	0:ac21159e27f4	684	* The ->next field of the last pbuf of the head chain is adjusted.
darran	0:ac21159e27f4	685	* The ->ref field of the first pbuf of the tail chain is adjusted.
darran	0:ac21159e27f4	686	*
darran	0:ac21159e27f4	687	*/
darran	0:ac21159e27f4	688	void
darran	0:ac21159e27f4	689	pbuf_chain(struct pbuf h, struct pbuf t)
darran	0:ac21159e27f4	690	{
darran	0:ac21159e27f4	691	pbuf_cat(h, t);
darran	0:ac21159e27f4	692	/* t is now referenced by h */
darran	0:ac21159e27f4	693	pbuf_ref(t);
darran	0:ac21159e27f4	694	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_chain: %p references %p\n", (void )h, (void )t));
darran	0:ac21159e27f4	695	}
darran	0:ac21159e27f4	696
darran	0:ac21159e27f4	697	/**
darran	0:ac21159e27f4	698	* Dechains the first pbuf from its succeeding pbufs in the chain.
darran	0:ac21159e27f4	699	*
darran	0:ac21159e27f4	700	* Makes p->tot_len field equal to p->len.
darran	0:ac21159e27f4	701	* @param p pbuf to dechain
darran	0:ac21159e27f4	702	* @return remainder of the pbuf chain, or NULL if it was de-allocated.
darran	0:ac21159e27f4	703	* @note May not be called on a packet queue.
darran	0:ac21159e27f4	704	*/
darran	0:ac21159e27f4	705	struct pbuf *
darran	0:ac21159e27f4	706	pbuf_dechain(struct pbuf *p)
darran	0:ac21159e27f4	707	{
darran	0:ac21159e27f4	708	struct pbuf *q;
darran	0:ac21159e27f4	709	u8_t tail_gone = 1;
darran	0:ac21159e27f4	710	/* tail */
darran	0:ac21159e27f4	711	q = p->next;
darran	0:ac21159e27f4	712	/* pbuf has successor in chain? */
darran	0:ac21159e27f4	713	if (q != NULL) {
darran	0:ac21159e27f4	714	/* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
darran	0:ac21159e27f4	715	LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len);
darran	0:ac21159e27f4	716	/* enforce invariant if assertion is disabled */
darran	0:ac21159e27f4	717	q->tot_len = p->tot_len - p->len;
darran	0:ac21159e27f4	718	/* decouple pbuf from remainder */
darran	0:ac21159e27f4	719	p->next = NULL;
darran	0:ac21159e27f4	720	/* total length of pbuf p is its own length only */
darran	0:ac21159e27f4	721	p->tot_len = p->len;
darran	0:ac21159e27f4	722	/* q is no longer referenced by p, free it */
darran	0:ac21159e27f4	723	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_dechain: unreferencing %p\n", (void *)q));
darran	0:ac21159e27f4	724	tail_gone = pbuf_free(q);
darran	0:ac21159e27f4	725	if (tail_gone > 0) {
darran	0:ac21159e27f4	726	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE,
darran	0:ac21159e27f4	727	("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q));
darran	0:ac21159e27f4	728	}
darran	0:ac21159e27f4	729	/* return remaining tail or NULL if deallocated */
darran	0:ac21159e27f4	730	}
darran	0:ac21159e27f4	731	/* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
darran	0:ac21159e27f4	732	LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len);
darran	0:ac21159e27f4	733	return ((tail_gone > 0) ? NULL : q);
darran	0:ac21159e27f4	734	}
darran	0:ac21159e27f4	735
darran	0:ac21159e27f4	736	/**
darran	0:ac21159e27f4	737	*
darran	0:ac21159e27f4	738	* Create PBUF_RAM copies of pbufs.
darran	0:ac21159e27f4	739	*
darran	0:ac21159e27f4	740	* Used to queue packets on behalf of the lwIP stack, such as
darran	0:ac21159e27f4	741	* ARP based queueing.
darran	0:ac21159e27f4	742	*
darran	0:ac21159e27f4	743	* @note You MUST explicitly use p = pbuf_take(p);
darran	0:ac21159e27f4	744	*
darran	0:ac21159e27f4	745	* @note Only one packet is copied, no packet queue!
darran	0:ac21159e27f4	746	*
darran	0:ac21159e27f4	747	* @param p_to pbuf destination of the copy
darran	0:ac21159e27f4	748	* @param p_from pbuf source of the copy
darran	0:ac21159e27f4	749	*
darran	0:ac21159e27f4	750	* @return ERR_OK if pbuf was copied
darran	0:ac21159e27f4	751	* ERR_ARG if one of the pbufs is NULL or p_to is not big
darran	0:ac21159e27f4	752	* enough to hold p_from
darran	0:ac21159e27f4	753	*/
darran	0:ac21159e27f4	754	err_t
darran	0:ac21159e27f4	755	pbuf_copy(struct pbuf p_to, struct pbuf p_from)
darran	0:ac21159e27f4	756	{
darran	0:ac21159e27f4	757	u16_t offset_to=0, offset_from=0, len;
darran	0:ac21159e27f4	758
darran	0:ac21159e27f4	759	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_copy(%p, %p)\n",
darran	0:ac21159e27f4	760	(void)p_to, (void)p_from));
darran	0:ac21159e27f4	761
darran	0:ac21159e27f4	762	/* is the target big enough to hold the source? */
darran	0:ac21159e27f4	763	LWIP_ERROR("pbuf_copy: target not big enough to hold source", ((p_to != NULL) &&
darran	0:ac21159e27f4	764	(p_from != NULL) && (p_to->tot_len >= p_from->tot_len)), return ERR_ARG;);
darran	0:ac21159e27f4	765
darran	0:ac21159e27f4	766	/* iterate through pbuf chain */
darran	0:ac21159e27f4	767	do
darran	0:ac21159e27f4	768	{
darran	0:ac21159e27f4	769	LWIP_ASSERT("p_to != NULL", p_to != NULL);
darran	0:ac21159e27f4	770	/* copy one part of the original chain */
darran	0:ac21159e27f4	771	if ((p_to->len - offset_to) >= (p_from->len - offset_from)) {
darran	0:ac21159e27f4	772	/* complete current p_from fits into current p_to */
darran	0:ac21159e27f4	773	len = p_from->len - offset_from;
darran	0:ac21159e27f4	774	} else {
darran	0:ac21159e27f4	775	/* current p_from does not fit into current p_to */
darran	0:ac21159e27f4	776	len = p_to->len - offset_to;
darran	0:ac21159e27f4	777	}
darran	0:ac21159e27f4	778	MEMCPY((u8_t)p_to->payload + offset_to, (u8_t)p_from->payload + offset_from, len);
darran	0:ac21159e27f4	779	offset_to += len;
darran	0:ac21159e27f4	780	offset_from += len;
darran	0:ac21159e27f4	781	LWIP_ASSERT("offset_to <= p_to->len", offset_to <= p_to->len);
darran	0:ac21159e27f4	782	if (offset_to == p_to->len) {
darran	0:ac21159e27f4	783	/* on to next p_to (if any) */
darran	0:ac21159e27f4	784	offset_to = 0;
darran	0:ac21159e27f4	785	p_to = p_to->next;
darran	0:ac21159e27f4	786	}
darran	0:ac21159e27f4	787	LWIP_ASSERT("offset_from <= p_from->len", offset_from <= p_from->len);
darran	0:ac21159e27f4	788	if (offset_from >= p_from->len) {
darran	0:ac21159e27f4	789	/* on to next p_from (if any) */
darran	0:ac21159e27f4	790	offset_from = 0;
darran	0:ac21159e27f4	791	p_from = p_from->next;
darran	0:ac21159e27f4	792	}
darran	0:ac21159e27f4	793
darran	0:ac21159e27f4	794	if((p_from != NULL) && (p_from->len == p_from->tot_len)) {
darran	0:ac21159e27f4	795	/* don't copy more than one packet! */
darran	0:ac21159e27f4	796	LWIP_ERROR("pbuf_copy() does not allow packet queues!\n",
darran	0:ac21159e27f4	797	(p_from->next == NULL), return ERR_VAL;);
darran	0:ac21159e27f4	798	}
darran	0:ac21159e27f4	799	if((p_to != NULL) && (p_to->len == p_to->tot_len)) {
darran	0:ac21159e27f4	800	/* don't copy more than one packet! */
darran	0:ac21159e27f4	801	LWIP_ERROR("pbuf_copy() does not allow packet queues!\n",
darran	0:ac21159e27f4	802	(p_to->next == NULL), return ERR_VAL;);
darran	0:ac21159e27f4	803	}
darran	0:ac21159e27f4	804	} while (p_from);
darran	0:ac21159e27f4	805	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_copy: end of chain reached.\n"));
darran	0:ac21159e27f4	806	return ERR_OK;
darran	0:ac21159e27f4	807	}
darran	0:ac21159e27f4	808
darran	0:ac21159e27f4	809	/**
darran	0:ac21159e27f4	810	* Copy (part of) the contents of a packet buffer
darran	0:ac21159e27f4	811	* to an application supplied buffer.
darran	0:ac21159e27f4	812	*
darran	0:ac21159e27f4	813	* @param buf the pbuf from which to copy data
darran	0:ac21159e27f4	814	* @param dataptr the application supplied buffer
darran	0:ac21159e27f4	815	* @param len length of data to copy (dataptr must be big enough). No more
darran	0:ac21159e27f4	816	* than buf->tot_len will be copied, irrespective of len
darran	0:ac21159e27f4	817	* @param offset offset into the packet buffer from where to begin copying len bytes
darran	0:ac21159e27f4	818	* @return the number of bytes copied, or 0 on failure
darran	0:ac21159e27f4	819	*/
darran	0:ac21159e27f4	820	u16_t
darran	0:ac21159e27f4	821	pbuf_copy_partial(struct pbuf buf, void dataptr, u16_t len, u16_t offset)
darran	0:ac21159e27f4	822	{
darran	0:ac21159e27f4	823	struct pbuf *p;
darran	0:ac21159e27f4	824	u16_t left;
darran	0:ac21159e27f4	825	u16_t buf_copy_len;
darran	0:ac21159e27f4	826	u16_t copied_total = 0;
darran	0:ac21159e27f4	827
darran	0:ac21159e27f4	828	LWIP_ERROR("pbuf_copy_partial: invalid buf", (buf != NULL), return 0;);
darran	0:ac21159e27f4	829	LWIP_ERROR("pbuf_copy_partial: invalid dataptr", (dataptr != NULL), return 0;);
darran	0:ac21159e27f4	830
darran	0:ac21159e27f4	831	left = 0;
darran	0:ac21159e27f4	832
darran	0:ac21159e27f4	833	if((buf == NULL) \|\| (dataptr == NULL)) {
darran	0:ac21159e27f4	834	return 0;
darran	0:ac21159e27f4	835	}
darran	0:ac21159e27f4	836
darran	0:ac21159e27f4	837	/* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
darran	0:ac21159e27f4	838	for(p = buf; len != 0 && p != NULL; p = p->next) {
darran	0:ac21159e27f4	839	if ((offset != 0) && (offset >= p->len)) {
darran	0:ac21159e27f4	840	/* don't copy from this buffer -> on to the next */
darran	0:ac21159e27f4	841	offset -= p->len;
darran	0:ac21159e27f4	842	} else {
darran	0:ac21159e27f4	843	/* copy from this buffer. maybe only partially. */
darran	0:ac21159e27f4	844	buf_copy_len = p->len - offset;
darran	0:ac21159e27f4	845	if (buf_copy_len > len)
darran	0:ac21159e27f4	846	buf_copy_len = len;
darran	0:ac21159e27f4	847	/* copy the necessary parts of the buffer */
darran	0:ac21159e27f4	848	MEMCPY(&((char)dataptr)[left], &((char)p->payload)[offset], buf_copy_len);
darran	0:ac21159e27f4	849	copied_total += buf_copy_len;
darran	0:ac21159e27f4	850	left += buf_copy_len;
darran	0:ac21159e27f4	851	len -= buf_copy_len;
darran	0:ac21159e27f4	852	offset = 0;
darran	0:ac21159e27f4	853	}
darran	0:ac21159e27f4	854	}
darran	0:ac21159e27f4	855	return copied_total;
darran	0:ac21159e27f4	856	}
darran	0:ac21159e27f4	857
darran	0:ac21159e27f4	858	/**
darran	0:ac21159e27f4	859	* Copy application supplied data into a pbuf.
darran	0:ac21159e27f4	860	* This function can only be used to copy the equivalent of buf->tot_len data.
darran	0:ac21159e27f4	861	*
darran	0:ac21159e27f4	862	* @param buf pbuf to fill with data
darran	0:ac21159e27f4	863	* @param dataptr application supplied data buffer
darran	0:ac21159e27f4	864	* @param len length of the application supplied data buffer
darran	0:ac21159e27f4	865	*
darran	0:ac21159e27f4	866	* @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough
darran	0:ac21159e27f4	867	*/
darran	0:ac21159e27f4	868	err_t
darran	0:ac21159e27f4	869	pbuf_take(struct pbuf buf, const void dataptr, u16_t len)
darran	0:ac21159e27f4	870	{
darran	0:ac21159e27f4	871	struct pbuf *p;
darran	0:ac21159e27f4	872	u16_t buf_copy_len;
darran	0:ac21159e27f4	873	u16_t total_copy_len = len;
darran	0:ac21159e27f4	874	u16_t copied_total = 0;
darran	0:ac21159e27f4	875
darran	0:ac21159e27f4	876	LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return 0;);
darran	0:ac21159e27f4	877	LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return 0;);
darran	0:ac21159e27f4	878
darran	0:ac21159e27f4	879	if ((buf == NULL) \|\| (dataptr == NULL) \|\| (buf->tot_len < len)) {
darran	0:ac21159e27f4	880	return ERR_ARG;
darran	0:ac21159e27f4	881	}
darran	0:ac21159e27f4	882
darran	0:ac21159e27f4	883	/* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
darran	0:ac21159e27f4	884	for(p = buf; total_copy_len != 0; p = p->next) {
darran	0:ac21159e27f4	885	LWIP_ASSERT("pbuf_take: invalid pbuf", p != NULL);
darran	0:ac21159e27f4	886	buf_copy_len = total_copy_len;
darran	0:ac21159e27f4	887	if (buf_copy_len > p->len) {
darran	0:ac21159e27f4	888	/* this pbuf cannot hold all remaining data */
darran	0:ac21159e27f4	889	buf_copy_len = p->len;
darran	0:ac21159e27f4	890	}
darran	0:ac21159e27f4	891	/* copy the necessary parts of the buffer */
darran	0:ac21159e27f4	892	MEMCPY(p->payload, &((char*)dataptr)[copied_total], buf_copy_len);
darran	0:ac21159e27f4	893	total_copy_len -= buf_copy_len;
darran	0:ac21159e27f4	894	copied_total += buf_copy_len;
darran	0:ac21159e27f4	895	}
darran	0:ac21159e27f4	896	LWIP_ASSERT("did not copy all data", total_copy_len == 0 && copied_total == len);
darran	0:ac21159e27f4	897	return ERR_OK;
darran	0:ac21159e27f4	898	}
darran	0:ac21159e27f4	899
darran	0:ac21159e27f4	900	/**
darran	0:ac21159e27f4	901	* Creates a single pbuf out of a queue of pbufs.
darran	0:ac21159e27f4	902	*
darran	0:ac21159e27f4	903	* @remark: The source pbuf 'p' is not freed by this function because that can
darran	0:ac21159e27f4	904	* be illegal in some places!
darran	0:ac21159e27f4	905	*
darran	0:ac21159e27f4	906	* @param p the source pbuf
darran	0:ac21159e27f4	907	* @param layer pbuf_layer of the new pbuf
darran	0:ac21159e27f4	908	*
darran	0:ac21159e27f4	909	* @return a new, single pbuf (p->next is NULL)
darran	0:ac21159e27f4	910	* or the old pbuf if allocation fails
darran	0:ac21159e27f4	911	*/
darran	0:ac21159e27f4	912	struct pbuf*
darran	0:ac21159e27f4	913	pbuf_coalesce(struct pbuf *p, pbuf_layer layer)
darran	0:ac21159e27f4	914	{
darran	0:ac21159e27f4	915	struct pbuf *q;
darran	0:ac21159e27f4	916	err_t err;
darran	0:ac21159e27f4	917	if (p->next == NULL) {
darran	0:ac21159e27f4	918	return p;
darran	0:ac21159e27f4	919	}
darran	0:ac21159e27f4	920	q = pbuf_alloc(layer, p->tot_len, PBUF_RAM);
darran	0:ac21159e27f4	921	if (q == NULL) {
darran	0:ac21159e27f4	922	/* @todo: what do we do now? */
darran	0:ac21159e27f4	923	return p;
darran	0:ac21159e27f4	924	}
darran	0:ac21159e27f4	925	err = pbuf_copy(q, p);
darran	0:ac21159e27f4	926	LWIP_ASSERT("pbuf_copy failed", err == ERR_OK);
darran	0:ac21159e27f4	927	pbuf_free(p);
darran	0:ac21159e27f4	928	return q;
darran	0:ac21159e27f4	929	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	02 Jul 2010
Imports:	2
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	1
Followers:	1

lwip/core/pbuf.c@0:ac21159e27f4, 2010-07-02 (annotated)

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