Bonjour - Bonjour/Zerconf library

Users » dirkx » Code » Bonjour

Dirk-Willem van Gulik (NXP/mbed) / Mbed 2 deprecated Bonjour

Bonjour/Zerconf library

lwip/core/pbuf.c@5:8e53abda9900, 2010-08-14 (annotated)

Committer:: dirkx
Date:: Sat Aug 14 15:54:31 2010 +0000
Revision:: 5:8e53abda9900
Parent:: 0:355018f44c9f

Who changed what in which revision?

User	Revision	Line number	New contents of line
dirkx	0:355018f44c9f	1	/**
dirkx	0:355018f44c9f	2	* @file
dirkx	0:355018f44c9f	3	* Packet buffer management
dirkx	0:355018f44c9f	4	*
dirkx	0:355018f44c9f	5	* Packets are built from the pbuf data structure. It supports dynamic
dirkx	0:355018f44c9f	6	* memory allocation for packet contents or can reference externally
dirkx	0:355018f44c9f	7	* managed packet contents both in RAM and ROM. Quick allocation for
dirkx	0:355018f44c9f	8	* incoming packets is provided through pools with fixed sized pbufs.
dirkx	0:355018f44c9f	9	*
dirkx	0:355018f44c9f	10	* A packet may span over multiple pbufs, chained as a singly linked
dirkx	0:355018f44c9f	11	* list. This is called a "pbuf chain".
dirkx	0:355018f44c9f	12	*
dirkx	0:355018f44c9f	13	* Multiple packets may be queued, also using this singly linked list.
dirkx	0:355018f44c9f	14	* This is called a "packet queue".
dirkx	0:355018f44c9f	15	*
dirkx	0:355018f44c9f	16	* So, a packet queue consists of one or more pbuf chains, each of
dirkx	0:355018f44c9f	17	* which consist of one or more pbufs. CURRENTLY, PACKET QUEUES ARE
dirkx	0:355018f44c9f	18	* NOT SUPPORTED!!! Use helper structs to queue multiple packets.
dirkx	0:355018f44c9f	19	*
dirkx	0:355018f44c9f	20	* The differences between a pbuf chain and a packet queue are very
dirkx	0:355018f44c9f	21	* precise but subtle.
dirkx	0:355018f44c9f	22	*
dirkx	0:355018f44c9f	23	* The last pbuf of a packet has a ->tot_len field that equals the
dirkx	0:355018f44c9f	24	* ->len field. It can be found by traversing the list. If the last
dirkx	0:355018f44c9f	25	* pbuf of a packet has a ->next field other than NULL, more packets
dirkx	0:355018f44c9f	26	* are on the queue.
dirkx	0:355018f44c9f	27	*
dirkx	0:355018f44c9f	28	* Therefore, looping through a pbuf of a single packet, has an
dirkx	0:355018f44c9f	29	* loop end condition (tot_len == p->len), NOT (next == NULL).
dirkx	0:355018f44c9f	30	*/
dirkx	0:355018f44c9f	31
dirkx	0:355018f44c9f	32	/*
dirkx	0:355018f44c9f	33	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
dirkx	0:355018f44c9f	34	* All rights reserved.
dirkx	0:355018f44c9f	35	*
dirkx	0:355018f44c9f	36	* Redistribution and use in source and binary forms, with or without modification,
dirkx	0:355018f44c9f	37	* are permitted provided that the following conditions are met:
dirkx	0:355018f44c9f	38	*
dirkx	0:355018f44c9f	39	* 1. Redistributions of source code must retain the above copyright notice,
dirkx	0:355018f44c9f	40	* this list of conditions and the following disclaimer.
dirkx	0:355018f44c9f	41	* 2. Redistributions in binary form must reproduce the above copyright notice,
dirkx	0:355018f44c9f	42	* this list of conditions and the following disclaimer in the documentation
dirkx	0:355018f44c9f	43	* and/or other materials provided with the distribution.
dirkx	0:355018f44c9f	44	* 3. The name of the author may not be used to endorse or promote products
dirkx	0:355018f44c9f	45	* derived from this software without specific prior written permission.
dirkx	0:355018f44c9f	46	*
dirkx	0:355018f44c9f	47	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
dirkx	0:355018f44c9f	48	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
dirkx	0:355018f44c9f	49	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
dirkx	0:355018f44c9f	50	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
dirkx	0:355018f44c9f	51	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
dirkx	0:355018f44c9f	52	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
dirkx	0:355018f44c9f	53	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
dirkx	0:355018f44c9f	54	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
dirkx	0:355018f44c9f	55	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
dirkx	0:355018f44c9f	56	* OF SUCH DAMAGE.
dirkx	0:355018f44c9f	57	*
dirkx	0:355018f44c9f	58	* This file is part of the lwIP TCP/IP stack.
dirkx	0:355018f44c9f	59	*
dirkx	0:355018f44c9f	60	* Author: Adam Dunkels <adam@sics.se>
dirkx	0:355018f44c9f	61	*
dirkx	0:355018f44c9f	62	*/
dirkx	0:355018f44c9f	63
dirkx	0:355018f44c9f	64	#include "lwip/opt.h"
dirkx	0:355018f44c9f	65
dirkx	0:355018f44c9f	66	#include "lwip/stats.h"
dirkx	0:355018f44c9f	67	#include "lwip/def.h"
dirkx	0:355018f44c9f	68	#include "lwip/mem.h"
dirkx	0:355018f44c9f	69	#include "lwip/memp.h"
dirkx	0:355018f44c9f	70	#include "lwip/pbuf.h"
dirkx	0:355018f44c9f	71	#include "lwip/sys.h"
dirkx	0:355018f44c9f	72	#include "arch/perf.h"
dirkx	0:355018f44c9f	73	#if TCP_QUEUE_OOSEQ
dirkx	0:355018f44c9f	74	#include "lwip/tcp_impl.h"
dirkx	0:355018f44c9f	75	#endif
dirkx	0:355018f44c9f	76
dirkx	0:355018f44c9f	77	#include <string.h>
dirkx	0:355018f44c9f	78
dirkx	0:355018f44c9f	79	#define SIZEOF_STRUCT_PBUF LWIP_MEM_ALIGN_SIZE(sizeof(struct pbuf))
dirkx	0:355018f44c9f	80	/* Since the pool is created in memp, PBUF_POOL_BUFSIZE will be automatically
dirkx	0:355018f44c9f	81	aligned there. Therefore, PBUF_POOL_BUFSIZE_ALIGNED can be used here. */
dirkx	0:355018f44c9f	82	#define PBUF_POOL_BUFSIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE)
dirkx	0:355018f44c9f	83
dirkx	0:355018f44c9f	84	#if !TCP_QUEUE_OOSEQ \|\| NO_SYS
dirkx	0:355018f44c9f	85	#define PBUF_POOL_IS_EMPTY()
dirkx	0:355018f44c9f	86	#else /* !TCP_QUEUE_OOSEQ \|\| NO_SYS */
dirkx	0:355018f44c9f	87	/** Define this to 0 to prevent freeing ooseq pbufs when the PBUF_POOL is empty */
dirkx	0:355018f44c9f	88	#ifndef PBUF_POOL_FREE_OOSEQ
dirkx	0:355018f44c9f	89	#define PBUF_POOL_FREE_OOSEQ 1
dirkx	0:355018f44c9f	90	#endif /* PBUF_POOL_FREE_OOSEQ */
dirkx	0:355018f44c9f	91
dirkx	0:355018f44c9f	92	#if PBUF_POOL_FREE_OOSEQ
dirkx	0:355018f44c9f	93	#include "lwip/tcpip.h"
dirkx	0:355018f44c9f	94	#define PBUF_POOL_IS_EMPTY() pbuf_pool_is_empty()
dirkx	0:355018f44c9f	95	static u8_t pbuf_free_ooseq_queued;
dirkx	0:355018f44c9f	96	/**
dirkx	0:355018f44c9f	97	* Attempt to reclaim some memory from queued out-of-sequence TCP segments
dirkx	0:355018f44c9f	98	* if we run out of pool pbufs. It's better to give priority to new packets
dirkx	0:355018f44c9f	99	* if we're running out.
dirkx	0:355018f44c9f	100	*
dirkx	0:355018f44c9f	101	* This must be done in the correct thread context therefore this function
dirkx	0:355018f44c9f	102	* can only be used with NO_SYS=0 and through tcpip_callback.
dirkx	0:355018f44c9f	103	*/
dirkx	0:355018f44c9f	104	static void
dirkx	0:355018f44c9f	105	pbuf_free_ooseq(void* arg)
dirkx	0:355018f44c9f	106	{
dirkx	0:355018f44c9f	107	struct tcp_pcb* pcb;
dirkx	0:355018f44c9f	108	SYS_ARCH_DECL_PROTECT(old_level);
dirkx	0:355018f44c9f	109	LWIP_UNUSED_ARG(arg);
dirkx	0:355018f44c9f	110
dirkx	0:355018f44c9f	111	SYS_ARCH_PROTECT(old_level);
dirkx	0:355018f44c9f	112	pbuf_free_ooseq_queued = 0;
dirkx	0:355018f44c9f	113	SYS_ARCH_UNPROTECT(old_level);
dirkx	0:355018f44c9f	114
dirkx	0:355018f44c9f	115	for (pcb = tcp_active_pcbs; NULL != pcb; pcb = pcb->next) {
dirkx	0:355018f44c9f	116	if (NULL != pcb->ooseq) {
dirkx	0:355018f44c9f	117	/** Free the ooseq pbufs of one PCB only */
dirkx	0:355018f44c9f	118	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_free_ooseq: freeing out-of-sequence pbufs\n"));
dirkx	0:355018f44c9f	119	tcp_segs_free(pcb->ooseq);
dirkx	0:355018f44c9f	120	pcb->ooseq = NULL;
dirkx	0:355018f44c9f	121	return;
dirkx	0:355018f44c9f	122	}
dirkx	0:355018f44c9f	123	}
dirkx	0:355018f44c9f	124	}
dirkx	0:355018f44c9f	125
dirkx	0:355018f44c9f	126	/** Queue a call to pbuf_free_ooseq if not already queued. */
dirkx	0:355018f44c9f	127	static void
dirkx	0:355018f44c9f	128	pbuf_pool_is_empty(void)
dirkx	0:355018f44c9f	129	{
dirkx	0:355018f44c9f	130	u8_t queued;
dirkx	0:355018f44c9f	131	SYS_ARCH_DECL_PROTECT(old_level);
dirkx	0:355018f44c9f	132
dirkx	0:355018f44c9f	133	SYS_ARCH_PROTECT(old_level);
dirkx	0:355018f44c9f	134	queued = pbuf_free_ooseq_queued;
dirkx	0:355018f44c9f	135	pbuf_free_ooseq_queued = 1;
dirkx	0:355018f44c9f	136	SYS_ARCH_UNPROTECT(old_level);
dirkx	0:355018f44c9f	137
dirkx	0:355018f44c9f	138	if(!queued) {
dirkx	0:355018f44c9f	139	/* queue a call to pbuf_free_ooseq if not already queued */
dirkx	0:355018f44c9f	140	if(tcpip_callback_with_block(pbuf_free_ooseq, NULL, 0) != ERR_OK) {
dirkx	0:355018f44c9f	141	SYS_ARCH_PROTECT(old_level);
dirkx	0:355018f44c9f	142	pbuf_free_ooseq_queued = 0;
dirkx	0:355018f44c9f	143	SYS_ARCH_UNPROTECT(old_level);
dirkx	0:355018f44c9f	144	}
dirkx	0:355018f44c9f	145	}
dirkx	0:355018f44c9f	146	}
dirkx	0:355018f44c9f	147	#endif /* PBUF_POOL_FREE_OOSEQ */
dirkx	0:355018f44c9f	148	#endif /* !TCP_QUEUE_OOSEQ \|\| NO_SYS */
dirkx	0:355018f44c9f	149
dirkx	0:355018f44c9f	150	/**
dirkx	0:355018f44c9f	151	* Allocates a pbuf of the given type (possibly a chain for PBUF_POOL type).
dirkx	0:355018f44c9f	152	*
dirkx	0:355018f44c9f	153	* The actual memory allocated for the pbuf is determined by the
dirkx	0:355018f44c9f	154	* layer at which the pbuf is allocated and the requested size
dirkx	0:355018f44c9f	155	* (from the size parameter).
dirkx	0:355018f44c9f	156	*
dirkx	0:355018f44c9f	157	* @param layer flag to define header size
dirkx	0:355018f44c9f	158	* @param length size of the pbuf's payload
dirkx	0:355018f44c9f	159	* @param type this parameter decides how and where the pbuf
dirkx	0:355018f44c9f	160	* should be allocated as follows:
dirkx	0:355018f44c9f	161	*
dirkx	0:355018f44c9f	162	* - PBUF_RAM: buffer memory for pbuf is allocated as one large
dirkx	0:355018f44c9f	163	* chunk. This includes protocol headers as well.
dirkx	0:355018f44c9f	164	* - PBUF_ROM: no buffer memory is allocated for the pbuf, even for
dirkx	0:355018f44c9f	165	* protocol headers. Additional headers must be prepended
dirkx	0:355018f44c9f	166	* by allocating another pbuf and chain in to the front of
dirkx	0:355018f44c9f	167	* the ROM pbuf. It is assumed that the memory used is really
dirkx	0:355018f44c9f	168	* similar to ROM in that it is immutable and will not be
dirkx	0:355018f44c9f	169	* changed. Memory which is dynamic should generally not
dirkx	0:355018f44c9f	170	* be attached to PBUF_ROM pbufs. Use PBUF_REF instead.
dirkx	0:355018f44c9f	171	* - PBUF_REF: no buffer memory is allocated for the pbuf, even for
dirkx	0:355018f44c9f	172	* protocol headers. It is assumed that the pbuf is only
dirkx	0:355018f44c9f	173	* being used in a single thread. If the pbuf gets queued,
dirkx	0:355018f44c9f	174	* then pbuf_take should be called to copy the buffer.
dirkx	0:355018f44c9f	175	* - PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from
dirkx	0:355018f44c9f	176	* the pbuf pool that is allocated during pbuf_init().
dirkx	0:355018f44c9f	177	*
dirkx	0:355018f44c9f	178	* @return the allocated pbuf. If multiple pbufs where allocated, this
dirkx	0:355018f44c9f	179	* is the first pbuf of a pbuf chain.
dirkx	0:355018f44c9f	180	*/
dirkx	0:355018f44c9f	181	struct pbuf *
dirkx	0:355018f44c9f	182	pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type)
dirkx	0:355018f44c9f	183	{
dirkx	0:355018f44c9f	184	struct pbuf p, q, *r;
dirkx	0:355018f44c9f	185	u16_t offset;
dirkx	0:355018f44c9f	186	s32_t rem_len; /* remaining length */
dirkx	0:355018f44c9f	187	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F")\n", length));
dirkx	0:355018f44c9f	188
dirkx	0:355018f44c9f	189	/* determine header offset */
dirkx	0:355018f44c9f	190	offset = 0;
dirkx	0:355018f44c9f	191	switch (layer) {
dirkx	0:355018f44c9f	192	case PBUF_TRANSPORT:
dirkx	0:355018f44c9f	193	/* add room for transport (often TCP) layer header */
dirkx	0:355018f44c9f	194	offset += PBUF_TRANSPORT_HLEN;
dirkx	0:355018f44c9f	195	/* FALLTHROUGH */
dirkx	0:355018f44c9f	196	case PBUF_IP:
dirkx	0:355018f44c9f	197	/* add room for IP layer header */
dirkx	0:355018f44c9f	198	offset += PBUF_IP_HLEN;
dirkx	0:355018f44c9f	199	/* FALLTHROUGH */
dirkx	0:355018f44c9f	200	case PBUF_LINK:
dirkx	0:355018f44c9f	201	/* add room for link layer header */
dirkx	0:355018f44c9f	202	offset += PBUF_LINK_HLEN;
dirkx	0:355018f44c9f	203	break;
dirkx	0:355018f44c9f	204	case PBUF_RAW:
dirkx	0:355018f44c9f	205	break;
dirkx	0:355018f44c9f	206	default:
dirkx	0:355018f44c9f	207	LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0);
dirkx	0:355018f44c9f	208	return NULL;
dirkx	0:355018f44c9f	209	}
dirkx	0:355018f44c9f	210
dirkx	0:355018f44c9f	211	switch (type) {
dirkx	0:355018f44c9f	212	case PBUF_POOL:
dirkx	0:355018f44c9f	213	/* allocate head of pbuf chain into p */
dirkx	0:355018f44c9f	214	p = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
dirkx	0:355018f44c9f	215	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_alloc: allocated pbuf %p\n", (void *)p));
dirkx	0:355018f44c9f	216	if (p == NULL) {
dirkx	0:355018f44c9f	217	PBUF_POOL_IS_EMPTY();
dirkx	0:355018f44c9f	218	return NULL;
dirkx	0:355018f44c9f	219	}
dirkx	0:355018f44c9f	220	p->type = type;
dirkx	0:355018f44c9f	221	p->next = NULL;
dirkx	0:355018f44c9f	222
dirkx	0:355018f44c9f	223	/* make the payload pointer point 'offset' bytes into pbuf data memory */
dirkx	0:355018f44c9f	224	p->payload = LWIP_MEM_ALIGN((void )((u8_t )p + (SIZEOF_STRUCT_PBUF + offset)));
dirkx	0:355018f44c9f	225	LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned",
dirkx	0:355018f44c9f	226	((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
dirkx	0:355018f44c9f	227	/* the total length of the pbuf chain is the requested size */
dirkx	0:355018f44c9f	228	p->tot_len = length;
dirkx	0:355018f44c9f	229	/* set the length of the first pbuf in the chain */
dirkx	0:355018f44c9f	230	p->len = LWIP_MIN(length, PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset));
dirkx	0:355018f44c9f	231	LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
dirkx	0:355018f44c9f	232	((u8_t*)p->payload + p->len <=
dirkx	0:355018f44c9f	233	(u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
dirkx	0:355018f44c9f	234	LWIP_ASSERT("PBUF_POOL_BUFSIZE must be bigger than MEM_ALIGNMENT",
dirkx	0:355018f44c9f	235	(PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)) > 0 );
dirkx	0:355018f44c9f	236	/* set reference count (needed here in case we fail) */
dirkx	0:355018f44c9f	237	p->ref = 1;
dirkx	0:355018f44c9f	238
dirkx	0:355018f44c9f	239	/* now allocate the tail of the pbuf chain */
dirkx	0:355018f44c9f	240
dirkx	0:355018f44c9f	241	/* remember first pbuf for linkage in next iteration */
dirkx	0:355018f44c9f	242	r = p;
dirkx	0:355018f44c9f	243	/* remaining length to be allocated */
dirkx	0:355018f44c9f	244	rem_len = length - p->len;
dirkx	0:355018f44c9f	245	/* any remaining pbufs to be allocated? */
dirkx	0:355018f44c9f	246	while (rem_len > 0) {
dirkx	0:355018f44c9f	247	q = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
dirkx	0:355018f44c9f	248	if (q == NULL) {
dirkx	0:355018f44c9f	249	PBUF_POOL_IS_EMPTY();
dirkx	0:355018f44c9f	250	/* free chain so far allocated */
dirkx	0:355018f44c9f	251	pbuf_free(p);
dirkx	0:355018f44c9f	252	/* bail out unsuccesfully */
dirkx	0:355018f44c9f	253	return NULL;
dirkx	0:355018f44c9f	254	}
dirkx	0:355018f44c9f	255	q->type = type;
dirkx	0:355018f44c9f	256	q->flags = 0;
dirkx	0:355018f44c9f	257	q->next = NULL;
dirkx	0:355018f44c9f	258	/* make previous pbuf point to this pbuf */
dirkx	0:355018f44c9f	259	r->next = q;
dirkx	0:355018f44c9f	260	/* set total length of this pbuf and next in chain */
dirkx	0:355018f44c9f	261	LWIP_ASSERT("rem_len < max_u16_t", rem_len < 0xffff);
dirkx	0:355018f44c9f	262	q->tot_len = (u16_t)rem_len;
dirkx	0:355018f44c9f	263	/* this pbuf length is pool size, unless smaller sized tail */
dirkx	0:355018f44c9f	264	q->len = LWIP_MIN((u16_t)rem_len, PBUF_POOL_BUFSIZE_ALIGNED);
dirkx	0:355018f44c9f	265	q->payload = (void )((u8_t )q + SIZEOF_STRUCT_PBUF);
dirkx	0:355018f44c9f	266	LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned",
dirkx	0:355018f44c9f	267	((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0);
dirkx	0:355018f44c9f	268	LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
dirkx	0:355018f44c9f	269	((u8_t*)p->payload + p->len <=
dirkx	0:355018f44c9f	270	(u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
dirkx	0:355018f44c9f	271	q->ref = 1;
dirkx	0:355018f44c9f	272	/* calculate remaining length to be allocated */
dirkx	0:355018f44c9f	273	rem_len -= q->len;
dirkx	0:355018f44c9f	274	/* remember this pbuf for linkage in next iteration */
dirkx	0:355018f44c9f	275	r = q;
dirkx	0:355018f44c9f	276	}
dirkx	0:355018f44c9f	277	/* end of chain */
dirkx	0:355018f44c9f	278	/r->next = NULL;/
dirkx	0:355018f44c9f	279
dirkx	0:355018f44c9f	280	break;
dirkx	0:355018f44c9f	281	case PBUF_RAM:
dirkx	0:355018f44c9f	282	/* If pbuf is to be allocated in RAM, allocate memory for it. */
dirkx	0:355018f44c9f	283	p = (struct pbuf*)mem_malloc(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length));
dirkx	0:355018f44c9f	284	if (p == NULL) {
dirkx	0:355018f44c9f	285	return NULL;
dirkx	0:355018f44c9f	286	}
dirkx	0:355018f44c9f	287	/* Set up internal structure of the pbuf. */
dirkx	0:355018f44c9f	288	p->payload = LWIP_MEM_ALIGN((void )((u8_t )p + SIZEOF_STRUCT_PBUF + offset));
dirkx	0:355018f44c9f	289	p->len = p->tot_len = length;
dirkx	0:355018f44c9f	290	p->next = NULL;
dirkx	0:355018f44c9f	291	p->type = type;
dirkx	0:355018f44c9f	292
dirkx	0:355018f44c9f	293	LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned",
dirkx	0:355018f44c9f	294	((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
dirkx	0:355018f44c9f	295	break;
dirkx	0:355018f44c9f	296	/* pbuf references existing (non-volatile static constant) ROM payload? */
dirkx	0:355018f44c9f	297	case PBUF_ROM:
dirkx	0:355018f44c9f	298	/* pbuf references existing (externally allocated) RAM payload? */
dirkx	0:355018f44c9f	299	case PBUF_REF:
dirkx	0:355018f44c9f	300	/* only allocate memory for the pbuf structure */
dirkx	0:355018f44c9f	301	p = (struct pbuf *)memp_malloc(MEMP_PBUF);
dirkx	0:355018f44c9f	302	if (p == NULL) {
dirkx	0:355018f44c9f	303	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_LEVEL_SERIOUS,
dirkx	0:355018f44c9f	304	("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n",
dirkx	0:355018f44c9f	305	(type == PBUF_ROM) ? "ROM" : "REF"));
dirkx	0:355018f44c9f	306	return NULL;
dirkx	0:355018f44c9f	307	}
dirkx	0:355018f44c9f	308	/* caller must set this field properly, afterwards */
dirkx	0:355018f44c9f	309	p->payload = NULL;
dirkx	0:355018f44c9f	310	p->len = p->tot_len = length;
dirkx	0:355018f44c9f	311	p->next = NULL;
dirkx	0:355018f44c9f	312	p->type = type;
dirkx	0:355018f44c9f	313	break;
dirkx	0:355018f44c9f	314	default:
dirkx	0:355018f44c9f	315	LWIP_ASSERT("pbuf_alloc: erroneous type", 0);
dirkx	0:355018f44c9f	316	return NULL;
dirkx	0:355018f44c9f	317	}
dirkx	0:355018f44c9f	318	/* set reference count */
dirkx	0:355018f44c9f	319	p->ref = 1;
dirkx	0:355018f44c9f	320	/* set flags */
dirkx	0:355018f44c9f	321	p->flags = 0;
dirkx	0:355018f44c9f	322	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F") == %p\n", length, (void *)p));
dirkx	0:355018f44c9f	323	return p;
dirkx	0:355018f44c9f	324	}
dirkx	0:355018f44c9f	325
dirkx	0:355018f44c9f	326
dirkx	0:355018f44c9f	327	/**
dirkx	0:355018f44c9f	328	* Shrink a pbuf chain to a desired length.
dirkx	0:355018f44c9f	329	*
dirkx	0:355018f44c9f	330	* @param p pbuf to shrink.
dirkx	0:355018f44c9f	331	* @param new_len desired new length of pbuf chain
dirkx	0:355018f44c9f	332	*
dirkx	0:355018f44c9f	333	* Depending on the desired length, the first few pbufs in a chain might
dirkx	0:355018f44c9f	334	* be skipped and left unchanged. The new last pbuf in the chain will be
dirkx	0:355018f44c9f	335	* resized, and any remaining pbufs will be freed.
dirkx	0:355018f44c9f	336	*
dirkx	0:355018f44c9f	337	* @note If the pbuf is ROM/REF, only the ->tot_len and ->len fields are adjusted.
dirkx	0:355018f44c9f	338	* @note May not be called on a packet queue.
dirkx	0:355018f44c9f	339	*
dirkx	0:355018f44c9f	340	* @note Despite its name, pbuf_realloc cannot grow the size of a pbuf (chain).
dirkx	0:355018f44c9f	341	*/
dirkx	0:355018f44c9f	342	void
dirkx	0:355018f44c9f	343	pbuf_realloc(struct pbuf *p, u16_t new_len)
dirkx	0:355018f44c9f	344	{
dirkx	0:355018f44c9f	345	struct pbuf *q;
dirkx	0:355018f44c9f	346	u16_t rem_len; /* remaining length */
dirkx	0:355018f44c9f	347	s32_t grow;
dirkx	0:355018f44c9f	348
dirkx	0:355018f44c9f	349	LWIP_ASSERT("pbuf_realloc: p != NULL", p != NULL);
dirkx	0:355018f44c9f	350	LWIP_ASSERT("pbuf_realloc: sane p->type", p->type == PBUF_POOL \|\|
dirkx	0:355018f44c9f	351	p->type == PBUF_ROM \|\|
dirkx	0:355018f44c9f	352	p->type == PBUF_RAM \|\|
dirkx	0:355018f44c9f	353	p->type == PBUF_REF);
dirkx	0:355018f44c9f	354
dirkx	0:355018f44c9f	355	/* desired length larger than current length? */
dirkx	0:355018f44c9f	356	if (new_len >= p->tot_len) {
dirkx	0:355018f44c9f	357	/* enlarging not yet supported */
dirkx	0:355018f44c9f	358	return;
dirkx	0:355018f44c9f	359	}
dirkx	0:355018f44c9f	360
dirkx	0:355018f44c9f	361	/* the pbuf chain grows by (new_len - p->tot_len) bytes
dirkx	0:355018f44c9f	362	* (which may be negative in case of shrinking) */
dirkx	0:355018f44c9f	363	grow = new_len - p->tot_len;
dirkx	0:355018f44c9f	364
dirkx	0:355018f44c9f	365	/* first, step over any pbufs that should remain in the chain */
dirkx	0:355018f44c9f	366	rem_len = new_len;
dirkx	0:355018f44c9f	367	q = p;
dirkx	0:355018f44c9f	368	/* should this pbuf be kept? */
dirkx	0:355018f44c9f	369	while (rem_len > q->len) {
dirkx	0:355018f44c9f	370	/* decrease remaining length by pbuf length */
dirkx	0:355018f44c9f	371	rem_len -= q->len;
dirkx	0:355018f44c9f	372	/* decrease total length indicator */
dirkx	0:355018f44c9f	373	LWIP_ASSERT("grow < max_u16_t", grow < 0xffff);
dirkx	0:355018f44c9f	374	q->tot_len += (u16_t)grow;
dirkx	0:355018f44c9f	375	/* proceed to next pbuf in chain */
dirkx	0:355018f44c9f	376	q = q->next;
dirkx	0:355018f44c9f	377	LWIP_ASSERT("pbuf_realloc: q != NULL", q != NULL);
dirkx	0:355018f44c9f	378	}
dirkx	0:355018f44c9f	379	/* we have now reached the new last pbuf (in q) */
dirkx	0:355018f44c9f	380	/* rem_len == desired length for pbuf q */
dirkx	0:355018f44c9f	381
dirkx	0:355018f44c9f	382	/* shrink allocated memory for PBUF_RAM */
dirkx	0:355018f44c9f	383	/* (other types merely adjust their length fields */
dirkx	0:355018f44c9f	384	if ((q->type == PBUF_RAM) && (rem_len != q->len)) {
dirkx	0:355018f44c9f	385	/* reallocate and adjust the length of the pbuf that will be split */
dirkx	0:355018f44c9f	386	q = (struct pbuf )mem_trim(q, (u16_t)((u8_t )q->payload - (u8_t *)q) + rem_len);
dirkx	0:355018f44c9f	387	LWIP_ASSERT("mem_trim returned q == NULL", q != NULL);
dirkx	0:355018f44c9f	388	}
dirkx	0:355018f44c9f	389	/* adjust length fields for new last pbuf */
dirkx	0:355018f44c9f	390	q->len = rem_len;
dirkx	0:355018f44c9f	391	q->tot_len = q->len;
dirkx	0:355018f44c9f	392
dirkx	0:355018f44c9f	393	/* any remaining pbufs in chain? */
dirkx	0:355018f44c9f	394	if (q->next != NULL) {
dirkx	0:355018f44c9f	395	/* free remaining pbufs in chain */
dirkx	0:355018f44c9f	396	pbuf_free(q->next);
dirkx	0:355018f44c9f	397	}
dirkx	0:355018f44c9f	398	/* q is last packet in chain */
dirkx	0:355018f44c9f	399	q->next = NULL;
dirkx	0:355018f44c9f	400
dirkx	0:355018f44c9f	401	}
dirkx	0:355018f44c9f	402
dirkx	0:355018f44c9f	403	/**
dirkx	0:355018f44c9f	404	* Adjusts the payload pointer to hide or reveal headers in the payload.
dirkx	0:355018f44c9f	405	*
dirkx	0:355018f44c9f	406	* Adjusts the ->payload pointer so that space for a header
dirkx	0:355018f44c9f	407	* (dis)appears in the pbuf payload.
dirkx	0:355018f44c9f	408	*
dirkx	0:355018f44c9f	409	* The ->payload, ->tot_len and ->len fields are adjusted.
dirkx	0:355018f44c9f	410	*
dirkx	0:355018f44c9f	411	* @param p pbuf to change the header size.
dirkx	0:355018f44c9f	412	* @param header_size_increment Number of bytes to increment header size which
dirkx	0:355018f44c9f	413	* increases the size of the pbuf. New space is on the front.
dirkx	0:355018f44c9f	414	* (Using a negative value decreases the header size.)
dirkx	0:355018f44c9f	415	* If hdr_size_inc is 0, this function does nothing and returns succesful.
dirkx	0:355018f44c9f	416	*
dirkx	0:355018f44c9f	417	* PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so
dirkx	0:355018f44c9f	418	* the call will fail. A check is made that the increase in header size does
dirkx	0:355018f44c9f	419	* not move the payload pointer in front of the start of the buffer.
dirkx	0:355018f44c9f	420	* @return non-zero on failure, zero on success.
dirkx	0:355018f44c9f	421	*
dirkx	0:355018f44c9f	422	*/
dirkx	0:355018f44c9f	423	u8_t
dirkx	0:355018f44c9f	424	pbuf_header(struct pbuf *p, s16_t header_size_increment)
dirkx	0:355018f44c9f	425	{
dirkx	0:355018f44c9f	426	u16_t type;
dirkx	0:355018f44c9f	427	void *payload;
dirkx	0:355018f44c9f	428	u16_t increment_magnitude;
dirkx	0:355018f44c9f	429
dirkx	0:355018f44c9f	430	LWIP_ASSERT("p != NULL", p != NULL);
dirkx	0:355018f44c9f	431	if ((header_size_increment == 0) \|\| (p == NULL))
dirkx	0:355018f44c9f	432	return 0;
dirkx	0:355018f44c9f	433
dirkx	0:355018f44c9f	434	if (header_size_increment < 0){
dirkx	0:355018f44c9f	435	increment_magnitude = -header_size_increment;
dirkx	0:355018f44c9f	436	/* Check that we aren't going to move off the end of the pbuf */
dirkx	0:355018f44c9f	437	LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <= p->len), return 1;);
dirkx	0:355018f44c9f	438	} else {
dirkx	0:355018f44c9f	439	increment_magnitude = header_size_increment;
dirkx	0:355018f44c9f	440	#if 0
dirkx	0:355018f44c9f	441	/* Can't assert these as some callers speculatively call
dirkx	0:355018f44c9f	442	pbuf_header() to see if it's OK. Will return 1 below instead. */
dirkx	0:355018f44c9f	443	/* Check that we've got the correct type of pbuf to work with */
dirkx	0:355018f44c9f	444	LWIP_ASSERT("p->type == PBUF_RAM \|\| p->type == PBUF_POOL",
dirkx	0:355018f44c9f	445	p->type == PBUF_RAM \|\| p->type == PBUF_POOL);
dirkx	0:355018f44c9f	446	/* Check that we aren't going to move off the beginning of the pbuf */
dirkx	0:355018f44c9f	447	LWIP_ASSERT("p->payload - increment_magnitude >= p + SIZEOF_STRUCT_PBUF",
dirkx	0:355018f44c9f	448	(u8_t )p->payload - increment_magnitude >= (u8_t )p + SIZEOF_STRUCT_PBUF);
dirkx	0:355018f44c9f	449	#endif
dirkx	0:355018f44c9f	450	}
dirkx	0:355018f44c9f	451
dirkx	0:355018f44c9f	452	type = p->type;
dirkx	0:355018f44c9f	453	/* remember current payload pointer */
dirkx	0:355018f44c9f	454	payload = p->payload;
dirkx	0:355018f44c9f	455
dirkx	0:355018f44c9f	456	/* pbuf types containing payloads? */
dirkx	0:355018f44c9f	457	if (type == PBUF_RAM \|\| type == PBUF_POOL) {
dirkx	0:355018f44c9f	458	/* set new payload pointer */
dirkx	0:355018f44c9f	459	p->payload = (u8_t *)p->payload - header_size_increment;
dirkx	0:355018f44c9f	460	/* boundary check fails? */
dirkx	0:355018f44c9f	461	if ((u8_t )p->payload < (u8_t )p + SIZEOF_STRUCT_PBUF) {
dirkx	0:355018f44c9f	462	LWIP_DEBUGF( PBUF_DEBUG \| LWIP_DBG_LEVEL_SERIOUS,
dirkx	0:355018f44c9f	463	("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
dirkx	0:355018f44c9f	464	(void )p->payload, (void )(p + 1)));
dirkx	0:355018f44c9f	465	/* restore old payload pointer */
dirkx	0:355018f44c9f	466	p->payload = payload;
dirkx	0:355018f44c9f	467	/* bail out unsuccesfully */
dirkx	0:355018f44c9f	468	return 1;
dirkx	0:355018f44c9f	469	}
dirkx	0:355018f44c9f	470	/* pbuf types refering to external payloads? */
dirkx	0:355018f44c9f	471	} else if (type == PBUF_REF \|\| type == PBUF_ROM) {
dirkx	0:355018f44c9f	472	/* hide a header in the payload? */
dirkx	0:355018f44c9f	473	if ((header_size_increment < 0) && (increment_magnitude <= p->len)) {
dirkx	0:355018f44c9f	474	/* increase payload pointer */
dirkx	0:355018f44c9f	475	p->payload = (u8_t *)p->payload - header_size_increment;
dirkx	0:355018f44c9f	476	} else {
dirkx	0:355018f44c9f	477	/* cannot expand payload to front (yet!)
dirkx	0:355018f44c9f	478	* bail out unsuccesfully */
dirkx	0:355018f44c9f	479	return 1;
dirkx	0:355018f44c9f	480	}
dirkx	0:355018f44c9f	481	}
dirkx	0:355018f44c9f	482	else {
dirkx	0:355018f44c9f	483	/* Unknown type */
dirkx	0:355018f44c9f	484	LWIP_ASSERT("bad pbuf type", 0);
dirkx	0:355018f44c9f	485	return 1;
dirkx	0:355018f44c9f	486	}
dirkx	0:355018f44c9f	487	/* modify pbuf length fields */
dirkx	0:355018f44c9f	488	p->len += header_size_increment;
dirkx	0:355018f44c9f	489	p->tot_len += header_size_increment;
dirkx	0:355018f44c9f	490
dirkx	0:355018f44c9f	491	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_header: old %p new %p (%"S16_F")\n",
dirkx	0:355018f44c9f	492	(void )payload, (void )p->payload, header_size_increment));
dirkx	0:355018f44c9f	493
dirkx	0:355018f44c9f	494	return 0;
dirkx	0:355018f44c9f	495	}
dirkx	0:355018f44c9f	496
dirkx	0:355018f44c9f	497	/**
dirkx	0:355018f44c9f	498	* Dereference a pbuf chain or queue and deallocate any no-longer-used
dirkx	0:355018f44c9f	499	* pbufs at the head of this chain or queue.
dirkx	0:355018f44c9f	500	*
dirkx	0:355018f44c9f	501	* Decrements the pbuf reference count. If it reaches zero, the pbuf is
dirkx	0:355018f44c9f	502	* deallocated.
dirkx	0:355018f44c9f	503	*
dirkx	0:355018f44c9f	504	* For a pbuf chain, this is repeated for each pbuf in the chain,
dirkx	0:355018f44c9f	505	* up to the first pbuf which has a non-zero reference count after
dirkx	0:355018f44c9f	506	* decrementing. So, when all reference counts are one, the whole
dirkx	0:355018f44c9f	507	* chain is free'd.
dirkx	0:355018f44c9f	508	*
dirkx	0:355018f44c9f	509	* @param p The pbuf (chain) to be dereferenced.
dirkx	0:355018f44c9f	510	*
dirkx	0:355018f44c9f	511	* @return the number of pbufs that were de-allocated
dirkx	0:355018f44c9f	512	* from the head of the chain.
dirkx	0:355018f44c9f	513	*
dirkx	0:355018f44c9f	514	* @note MUST NOT be called on a packet queue (Not verified to work yet).
dirkx	0:355018f44c9f	515	* @note the reference counter of a pbuf equals the number of pointers
dirkx	0:355018f44c9f	516	* that refer to the pbuf (or into the pbuf).
dirkx	0:355018f44c9f	517	*
dirkx	0:355018f44c9f	518	* @internal examples:
dirkx	0:355018f44c9f	519	*
dirkx	0:355018f44c9f	520	* Assuming existing chains a->b->c with the following reference
dirkx	0:355018f44c9f	521	* counts, calling pbuf_free(a) results in:
dirkx	0:355018f44c9f	522	*
dirkx	0:355018f44c9f	523	* 1->2->3 becomes ...1->3
dirkx	0:355018f44c9f	524	* 3->3->3 becomes 2->3->3
dirkx	0:355018f44c9f	525	* 1->1->2 becomes ......1
dirkx	0:355018f44c9f	526	* 2->1->1 becomes 1->1->1
dirkx	0:355018f44c9f	527	* 1->1->1 becomes .......
dirkx	0:355018f44c9f	528	*
dirkx	0:355018f44c9f	529	*/
dirkx	0:355018f44c9f	530	u8_t
dirkx	0:355018f44c9f	531	pbuf_free(struct pbuf *p)
dirkx	0:355018f44c9f	532	{
dirkx	0:355018f44c9f	533	u16_t type;
dirkx	0:355018f44c9f	534	struct pbuf *q;
dirkx	0:355018f44c9f	535	u8_t count;
dirkx	0:355018f44c9f	536
dirkx	0:355018f44c9f	537	if (p == NULL) {
dirkx	0:355018f44c9f	538	LWIP_ASSERT("p != NULL", p != NULL);
dirkx	0:355018f44c9f	539	/* if assertions are disabled, proceed with debug output */
dirkx	0:355018f44c9f	540	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_LEVEL_SERIOUS,
dirkx	0:355018f44c9f	541	("pbuf_free(p == NULL) was called.\n"));
dirkx	0:355018f44c9f	542	return 0;
dirkx	0:355018f44c9f	543	}
dirkx	0:355018f44c9f	544	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_free(%p)\n", (void *)p));
dirkx	0:355018f44c9f	545
dirkx	0:355018f44c9f	546	PERF_START;
dirkx	0:355018f44c9f	547
dirkx	0:355018f44c9f	548	LWIP_ASSERT("pbuf_free: sane type",
dirkx	0:355018f44c9f	549	p->type == PBUF_RAM \|\| p->type == PBUF_ROM \|\|
dirkx	0:355018f44c9f	550	p->type == PBUF_REF \|\| p->type == PBUF_POOL);
dirkx	0:355018f44c9f	551
dirkx	0:355018f44c9f	552	count = 0;
dirkx	0:355018f44c9f	553	/* de-allocate all consecutive pbufs from the head of the chain that
dirkx	0:355018f44c9f	554	* obtain a zero reference count after decrementing*/
dirkx	0:355018f44c9f	555	while (p != NULL) {
dirkx	0:355018f44c9f	556	u16_t ref;
dirkx	0:355018f44c9f	557	SYS_ARCH_DECL_PROTECT(old_level);
dirkx	0:355018f44c9f	558	/* Since decrementing ref cannot be guaranteed to be a single machine operation
dirkx	0:355018f44c9f	559	* we must protect it. We put the new ref into a local variable to prevent
dirkx	0:355018f44c9f	560	* further protection. */
dirkx	0:355018f44c9f	561	SYS_ARCH_PROTECT(old_level);
dirkx	0:355018f44c9f	562	/* all pbufs in a chain are referenced at least once */
dirkx	0:355018f44c9f	563	LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);
dirkx	0:355018f44c9f	564	/* decrease reference count (number of pointers to pbuf) */
dirkx	0:355018f44c9f	565	ref = --(p->ref);
dirkx	0:355018f44c9f	566	SYS_ARCH_UNPROTECT(old_level);
dirkx	0:355018f44c9f	567	/* this pbuf is no longer referenced to? */
dirkx	0:355018f44c9f	568	if (ref == 0) {
dirkx	0:355018f44c9f	569	/* remember next pbuf in chain for next iteration */
dirkx	0:355018f44c9f	570	q = p->next;
dirkx	0:355018f44c9f	571	LWIP_DEBUGF( PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_free: deallocating %p\n", (void *)p));
dirkx	0:355018f44c9f	572	type = p->type;
dirkx	0:355018f44c9f	573	/* is this a pbuf from the pool? */
dirkx	0:355018f44c9f	574	if (type == PBUF_POOL) {
dirkx	0:355018f44c9f	575	memp_free(MEMP_PBUF_POOL, p);
dirkx	0:355018f44c9f	576	/* is this a ROM or RAM referencing pbuf? */
dirkx	0:355018f44c9f	577	} else if (type == PBUF_ROM \|\| type == PBUF_REF) {
dirkx	0:355018f44c9f	578	memp_free(MEMP_PBUF, p);
dirkx	0:355018f44c9f	579	/* type == PBUF_RAM */
dirkx	0:355018f44c9f	580	} else {
dirkx	0:355018f44c9f	581	mem_free(p);
dirkx	0:355018f44c9f	582	}
dirkx	0:355018f44c9f	583	count++;
dirkx	0:355018f44c9f	584	/* proceed to next pbuf */
dirkx	0:355018f44c9f	585	p = q;
dirkx	0:355018f44c9f	586	/* p->ref > 0, this pbuf is still referenced to */
dirkx	0:355018f44c9f	587	/* (and so the remaining pbufs in chain as well) */
dirkx	0:355018f44c9f	588	} else {
dirkx	0:355018f44c9f	589	LWIP_DEBUGF( PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, ref));
dirkx	0:355018f44c9f	590	/* stop walking through the chain */
dirkx	0:355018f44c9f	591	p = NULL;
dirkx	0:355018f44c9f	592	}
dirkx	0:355018f44c9f	593	}
dirkx	0:355018f44c9f	594	PERF_STOP("pbuf_free");
dirkx	0:355018f44c9f	595	/* return number of de-allocated pbufs */
dirkx	0:355018f44c9f	596	return count;
dirkx	0:355018f44c9f	597	}
dirkx	0:355018f44c9f	598
dirkx	0:355018f44c9f	599	/**
dirkx	0:355018f44c9f	600	* Count number of pbufs in a chain
dirkx	0:355018f44c9f	601	*
dirkx	0:355018f44c9f	602	* @param p first pbuf of chain
dirkx	0:355018f44c9f	603	* @return the number of pbufs in a chain
dirkx	0:355018f44c9f	604	*/
dirkx	0:355018f44c9f	605
dirkx	0:355018f44c9f	606	u8_t
dirkx	0:355018f44c9f	607	pbuf_clen(struct pbuf *p)
dirkx	0:355018f44c9f	608	{
dirkx	0:355018f44c9f	609	u8_t len;
dirkx	0:355018f44c9f	610
dirkx	0:355018f44c9f	611	len = 0;
dirkx	0:355018f44c9f	612	while (p != NULL) {
dirkx	0:355018f44c9f	613	++len;
dirkx	0:355018f44c9f	614	p = p->next;
dirkx	0:355018f44c9f	615	}
dirkx	0:355018f44c9f	616	return len;
dirkx	0:355018f44c9f	617	}
dirkx	0:355018f44c9f	618
dirkx	0:355018f44c9f	619	/**
dirkx	0:355018f44c9f	620	* Increment the reference count of the pbuf.
dirkx	0:355018f44c9f	621	*
dirkx	0:355018f44c9f	622	* @param p pbuf to increase reference counter of
dirkx	0:355018f44c9f	623	*
dirkx	0:355018f44c9f	624	*/
dirkx	0:355018f44c9f	625	void
dirkx	0:355018f44c9f	626	pbuf_ref(struct pbuf *p)
dirkx	0:355018f44c9f	627	{
dirkx	0:355018f44c9f	628	SYS_ARCH_DECL_PROTECT(old_level);
dirkx	0:355018f44c9f	629	/* pbuf given? */
dirkx	0:355018f44c9f	630	if (p != NULL) {
dirkx	0:355018f44c9f	631	SYS_ARCH_PROTECT(old_level);
dirkx	0:355018f44c9f	632	++(p->ref);
dirkx	0:355018f44c9f	633	SYS_ARCH_UNPROTECT(old_level);
dirkx	0:355018f44c9f	634	}
dirkx	0:355018f44c9f	635	}
dirkx	0:355018f44c9f	636
dirkx	0:355018f44c9f	637	/**
dirkx	0:355018f44c9f	638	* Concatenate two pbufs (each may be a pbuf chain) and take over
dirkx	0:355018f44c9f	639	* the caller's reference of the tail pbuf.
dirkx	0:355018f44c9f	640	*
dirkx	0:355018f44c9f	641	* @note The caller MAY NOT reference the tail pbuf afterwards.
dirkx	0:355018f44c9f	642	* Use pbuf_chain() for that purpose.
dirkx	0:355018f44c9f	643	*
dirkx	0:355018f44c9f	644	* @see pbuf_chain()
dirkx	0:355018f44c9f	645	*/
dirkx	0:355018f44c9f	646
dirkx	0:355018f44c9f	647	void
dirkx	0:355018f44c9f	648	pbuf_cat(struct pbuf h, struct pbuf t)
dirkx	0:355018f44c9f	649	{
dirkx	0:355018f44c9f	650	struct pbuf *p;
dirkx	0:355018f44c9f	651
dirkx	0:355018f44c9f	652	LWIP_ERROR("(h != NULL) && (t != NULL) (programmer violates API)",
dirkx	0:355018f44c9f	653	((h != NULL) && (t != NULL)), return;);
dirkx	0:355018f44c9f	654
dirkx	0:355018f44c9f	655	/* proceed to last pbuf of chain */
dirkx	0:355018f44c9f	656	for (p = h; p->next != NULL; p = p->next) {
dirkx	0:355018f44c9f	657	/* add total length of second chain to all totals of first chain */
dirkx	0:355018f44c9f	658	p->tot_len += t->tot_len;
dirkx	0:355018f44c9f	659	}
dirkx	0:355018f44c9f	660	/* { p is last pbuf of first h chain, p->next == NULL } */
dirkx	0:355018f44c9f	661	LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len);
dirkx	0:355018f44c9f	662	LWIP_ASSERT("p->next == NULL", p->next == NULL);
dirkx	0:355018f44c9f	663	/* add total length of second chain to last pbuf total of first chain */
dirkx	0:355018f44c9f	664	p->tot_len += t->tot_len;
dirkx	0:355018f44c9f	665	/* chain last pbuf of head (p) with first of tail (t) */
dirkx	0:355018f44c9f	666	p->next = t;
dirkx	0:355018f44c9f	667	/* p->next now references t, but the caller will drop its reference to t,
dirkx	0:355018f44c9f	668	* so netto there is no change to the reference count of t.
dirkx	0:355018f44c9f	669	*/
dirkx	0:355018f44c9f	670	}
dirkx	0:355018f44c9f	671
dirkx	0:355018f44c9f	672	/**
dirkx	0:355018f44c9f	673	* Chain two pbufs (or pbuf chains) together.
dirkx	0:355018f44c9f	674	*
dirkx	0:355018f44c9f	675	* The caller MUST call pbuf_free(t) once it has stopped
dirkx	0:355018f44c9f	676	* using it. Use pbuf_cat() instead if you no longer use t.
dirkx	0:355018f44c9f	677	*
dirkx	0:355018f44c9f	678	* @param h head pbuf (chain)
dirkx	0:355018f44c9f	679	* @param t tail pbuf (chain)
dirkx	0:355018f44c9f	680	* @note The pbufs MUST belong to the same packet.
dirkx	0:355018f44c9f	681	* @note MAY NOT be called on a packet queue.
dirkx	0:355018f44c9f	682	*
dirkx	0:355018f44c9f	683	* The ->tot_len fields of all pbufs of the head chain are adjusted.
dirkx	0:355018f44c9f	684	* The ->next field of the last pbuf of the head chain is adjusted.
dirkx	0:355018f44c9f	685	* The ->ref field of the first pbuf of the tail chain is adjusted.
dirkx	0:355018f44c9f	686	*
dirkx	0:355018f44c9f	687	*/
dirkx	0:355018f44c9f	688	void
dirkx	0:355018f44c9f	689	pbuf_chain(struct pbuf h, struct pbuf t)
dirkx	0:355018f44c9f	690	{
dirkx	0:355018f44c9f	691	pbuf_cat(h, t);
dirkx	0:355018f44c9f	692	/* t is now referenced by h */
dirkx	0:355018f44c9f	693	pbuf_ref(t);
dirkx	0:355018f44c9f	694	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_chain: %p references %p\n", (void )h, (void )t));
dirkx	0:355018f44c9f	695	}
dirkx	0:355018f44c9f	696
dirkx	0:355018f44c9f	697	/**
dirkx	0:355018f44c9f	698	* Dechains the first pbuf from its succeeding pbufs in the chain.
dirkx	0:355018f44c9f	699	*
dirkx	0:355018f44c9f	700	* Makes p->tot_len field equal to p->len.
dirkx	0:355018f44c9f	701	* @param p pbuf to dechain
dirkx	0:355018f44c9f	702	* @return remainder of the pbuf chain, or NULL if it was de-allocated.
dirkx	0:355018f44c9f	703	* @note May not be called on a packet queue.
dirkx	0:355018f44c9f	704	*/
dirkx	0:355018f44c9f	705	struct pbuf *
dirkx	0:355018f44c9f	706	pbuf_dechain(struct pbuf *p)
dirkx	0:355018f44c9f	707	{
dirkx	0:355018f44c9f	708	struct pbuf *q;
dirkx	0:355018f44c9f	709	u8_t tail_gone = 1;
dirkx	0:355018f44c9f	710	/* tail */
dirkx	0:355018f44c9f	711	q = p->next;
dirkx	0:355018f44c9f	712	/* pbuf has successor in chain? */
dirkx	0:355018f44c9f	713	if (q != NULL) {
dirkx	0:355018f44c9f	714	/* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
dirkx	0:355018f44c9f	715	LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len);
dirkx	0:355018f44c9f	716	/* enforce invariant if assertion is disabled */
dirkx	0:355018f44c9f	717	q->tot_len = p->tot_len - p->len;
dirkx	0:355018f44c9f	718	/* decouple pbuf from remainder */
dirkx	0:355018f44c9f	719	p->next = NULL;
dirkx	0:355018f44c9f	720	/* total length of pbuf p is its own length only */
dirkx	0:355018f44c9f	721	p->tot_len = p->len;
dirkx	0:355018f44c9f	722	/* q is no longer referenced by p, free it */
dirkx	0:355018f44c9f	723	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_dechain: unreferencing %p\n", (void *)q));
dirkx	0:355018f44c9f	724	tail_gone = pbuf_free(q);
dirkx	0:355018f44c9f	725	if (tail_gone > 0) {
dirkx	0:355018f44c9f	726	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE,
dirkx	0:355018f44c9f	727	("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q));
dirkx	0:355018f44c9f	728	}
dirkx	0:355018f44c9f	729	/* return remaining tail or NULL if deallocated */
dirkx	0:355018f44c9f	730	}
dirkx	0:355018f44c9f	731	/* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
dirkx	0:355018f44c9f	732	LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len);
dirkx	0:355018f44c9f	733	return ((tail_gone > 0) ? NULL : q);
dirkx	0:355018f44c9f	734	}
dirkx	0:355018f44c9f	735
dirkx	0:355018f44c9f	736	/**
dirkx	0:355018f44c9f	737	*
dirkx	0:355018f44c9f	738	* Create PBUF_RAM copies of pbufs.
dirkx	0:355018f44c9f	739	*
dirkx	0:355018f44c9f	740	* Used to queue packets on behalf of the lwIP stack, such as
dirkx	0:355018f44c9f	741	* ARP based queueing.
dirkx	0:355018f44c9f	742	*
dirkx	0:355018f44c9f	743	* @note You MUST explicitly use p = pbuf_take(p);
dirkx	0:355018f44c9f	744	*
dirkx	0:355018f44c9f	745	* @note Only one packet is copied, no packet queue!
dirkx	0:355018f44c9f	746	*
dirkx	0:355018f44c9f	747	* @param p_to pbuf destination of the copy
dirkx	0:355018f44c9f	748	* @param p_from pbuf source of the copy
dirkx	0:355018f44c9f	749	*
dirkx	0:355018f44c9f	750	* @return ERR_OK if pbuf was copied
dirkx	0:355018f44c9f	751	* ERR_ARG if one of the pbufs is NULL or p_to is not big
dirkx	0:355018f44c9f	752	* enough to hold p_from
dirkx	0:355018f44c9f	753	*/
dirkx	0:355018f44c9f	754	err_t
dirkx	0:355018f44c9f	755	pbuf_copy(struct pbuf p_to, struct pbuf p_from)
dirkx	0:355018f44c9f	756	{
dirkx	0:355018f44c9f	757	u16_t offset_to=0, offset_from=0, len;
dirkx	0:355018f44c9f	758
dirkx	0:355018f44c9f	759	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_copy(%p, %p)\n",
dirkx	0:355018f44c9f	760	(void)p_to, (void)p_from));
dirkx	0:355018f44c9f	761
dirkx	0:355018f44c9f	762	/* is the target big enough to hold the source? */
dirkx	0:355018f44c9f	763	LWIP_ERROR("pbuf_copy: target not big enough to hold source", ((p_to != NULL) &&
dirkx	0:355018f44c9f	764	(p_from != NULL) && (p_to->tot_len >= p_from->tot_len)), return ERR_ARG;);
dirkx	0:355018f44c9f	765
dirkx	0:355018f44c9f	766	/* iterate through pbuf chain */
dirkx	0:355018f44c9f	767	do
dirkx	0:355018f44c9f	768	{
dirkx	0:355018f44c9f	769	LWIP_ASSERT("p_to != NULL", p_to != NULL);
dirkx	0:355018f44c9f	770	/* copy one part of the original chain */
dirkx	0:355018f44c9f	771	if ((p_to->len - offset_to) >= (p_from->len - offset_from)) {
dirkx	0:355018f44c9f	772	/* complete current p_from fits into current p_to */
dirkx	0:355018f44c9f	773	len = p_from->len - offset_from;
dirkx	0:355018f44c9f	774	} else {
dirkx	0:355018f44c9f	775	/* current p_from does not fit into current p_to */
dirkx	0:355018f44c9f	776	len = p_to->len - offset_to;
dirkx	0:355018f44c9f	777	}
dirkx	0:355018f44c9f	778	MEMCPY((u8_t)p_to->payload + offset_to, (u8_t)p_from->payload + offset_from, len);
dirkx	0:355018f44c9f	779	offset_to += len;
dirkx	0:355018f44c9f	780	offset_from += len;
dirkx	0:355018f44c9f	781	LWIP_ASSERT("offset_to <= p_to->len", offset_to <= p_to->len);
dirkx	0:355018f44c9f	782	if (offset_to == p_to->len) {
dirkx	0:355018f44c9f	783	/* on to next p_to (if any) */
dirkx	0:355018f44c9f	784	offset_to = 0;
dirkx	0:355018f44c9f	785	p_to = p_to->next;
dirkx	0:355018f44c9f	786	}
dirkx	0:355018f44c9f	787	LWIP_ASSERT("offset_from <= p_from->len", offset_from <= p_from->len);
dirkx	0:355018f44c9f	788	if (offset_from >= p_from->len) {
dirkx	0:355018f44c9f	789	/* on to next p_from (if any) */
dirkx	0:355018f44c9f	790	offset_from = 0;
dirkx	0:355018f44c9f	791	p_from = p_from->next;
dirkx	0:355018f44c9f	792	}
dirkx	0:355018f44c9f	793
dirkx	0:355018f44c9f	794	if((p_from != NULL) && (p_from->len == p_from->tot_len)) {
dirkx	0:355018f44c9f	795	/* don't copy more than one packet! */
dirkx	0:355018f44c9f	796	LWIP_ERROR("pbuf_copy() does not allow packet queues!\n",
dirkx	0:355018f44c9f	797	(p_from->next == NULL), return ERR_VAL;);
dirkx	0:355018f44c9f	798	}
dirkx	0:355018f44c9f	799	if((p_to != NULL) && (p_to->len == p_to->tot_len)) {
dirkx	0:355018f44c9f	800	/* don't copy more than one packet! */
dirkx	0:355018f44c9f	801	LWIP_ERROR("pbuf_copy() does not allow packet queues!\n",
dirkx	0:355018f44c9f	802	(p_to->next == NULL), return ERR_VAL;);
dirkx	0:355018f44c9f	803	}
dirkx	0:355018f44c9f	804	} while (p_from);
dirkx	0:355018f44c9f	805	LWIP_DEBUGF(PBUF_DEBUG \| LWIP_DBG_TRACE, ("pbuf_copy: end of chain reached.\n"));
dirkx	0:355018f44c9f	806	return ERR_OK;
dirkx	0:355018f44c9f	807	}
dirkx	0:355018f44c9f	808
dirkx	0:355018f44c9f	809	/**
dirkx	0:355018f44c9f	810	* Copy (part of) the contents of a packet buffer
dirkx	0:355018f44c9f	811	* to an application supplied buffer.
dirkx	0:355018f44c9f	812	*
dirkx	0:355018f44c9f	813	* @param buf the pbuf from which to copy data
dirkx	0:355018f44c9f	814	* @param dataptr the application supplied buffer
dirkx	0:355018f44c9f	815	* @param len length of data to copy (dataptr must be big enough). No more
dirkx	0:355018f44c9f	816	* than buf->tot_len will be copied, irrespective of len
dirkx	0:355018f44c9f	817	* @param offset offset into the packet buffer from where to begin copying len bytes
dirkx	0:355018f44c9f	818	* @return the number of bytes copied, or 0 on failure
dirkx	0:355018f44c9f	819	*/
dirkx	0:355018f44c9f	820	u16_t
dirkx	0:355018f44c9f	821	pbuf_copy_partial(struct pbuf buf, void dataptr, u16_t len, u16_t offset)
dirkx	0:355018f44c9f	822	{
dirkx	0:355018f44c9f	823	struct pbuf *p;
dirkx	0:355018f44c9f	824	u16_t left;
dirkx	0:355018f44c9f	825	u16_t buf_copy_len;
dirkx	0:355018f44c9f	826	u16_t copied_total = 0;
dirkx	0:355018f44c9f	827
dirkx	0:355018f44c9f	828	LWIP_ERROR("pbuf_copy_partial: invalid buf", (buf != NULL), return 0;);
dirkx	0:355018f44c9f	829	LWIP_ERROR("pbuf_copy_partial: invalid dataptr", (dataptr != NULL), return 0;);
dirkx	0:355018f44c9f	830
dirkx	0:355018f44c9f	831	left = 0;
dirkx	0:355018f44c9f	832
dirkx	0:355018f44c9f	833	if((buf == NULL) \|\| (dataptr == NULL)) {
dirkx	0:355018f44c9f	834	return 0;
dirkx	0:355018f44c9f	835	}
dirkx	0:355018f44c9f	836
dirkx	0:355018f44c9f	837	/* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
dirkx	0:355018f44c9f	838	for(p = buf; len != 0 && p != NULL; p = p->next) {
dirkx	0:355018f44c9f	839	if ((offset != 0) && (offset >= p->len)) {
dirkx	0:355018f44c9f	840	/* don't copy from this buffer -> on to the next */
dirkx	0:355018f44c9f	841	offset -= p->len;
dirkx	0:355018f44c9f	842	} else {
dirkx	0:355018f44c9f	843	/* copy from this buffer. maybe only partially. */
dirkx	0:355018f44c9f	844	buf_copy_len = p->len - offset;
dirkx	0:355018f44c9f	845	if (buf_copy_len > len)
dirkx	0:355018f44c9f	846	buf_copy_len = len;
dirkx	0:355018f44c9f	847	/* copy the necessary parts of the buffer */
dirkx	0:355018f44c9f	848	MEMCPY(&((char)dataptr)[left], &((char)p->payload)[offset], buf_copy_len);
dirkx	0:355018f44c9f	849	copied_total += buf_copy_len;
dirkx	0:355018f44c9f	850	left += buf_copy_len;
dirkx	0:355018f44c9f	851	len -= buf_copy_len;
dirkx	0:355018f44c9f	852	offset = 0;
dirkx	0:355018f44c9f	853	}
dirkx	0:355018f44c9f	854	}
dirkx	0:355018f44c9f	855	return copied_total;
dirkx	0:355018f44c9f	856	}
dirkx	0:355018f44c9f	857
dirkx	0:355018f44c9f	858	/**
dirkx	0:355018f44c9f	859	* Copy application supplied data into a pbuf.
dirkx	0:355018f44c9f	860	* This function can only be used to copy the equivalent of buf->tot_len data.
dirkx	0:355018f44c9f	861	*
dirkx	0:355018f44c9f	862	* @param buf pbuf to fill with data
dirkx	0:355018f44c9f	863	* @param dataptr application supplied data buffer
dirkx	0:355018f44c9f	864	* @param len length of the application supplied data buffer
dirkx	0:355018f44c9f	865	*
dirkx	0:355018f44c9f	866	* @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough
dirkx	0:355018f44c9f	867	*/
dirkx	0:355018f44c9f	868	err_t
dirkx	0:355018f44c9f	869	pbuf_take(struct pbuf buf, const void dataptr, u16_t len)
dirkx	0:355018f44c9f	870	{
dirkx	0:355018f44c9f	871	struct pbuf *p;
dirkx	0:355018f44c9f	872	u16_t buf_copy_len;
dirkx	0:355018f44c9f	873	u16_t total_copy_len = len;
dirkx	0:355018f44c9f	874	u16_t copied_total = 0;
dirkx	0:355018f44c9f	875
dirkx	0:355018f44c9f	876	LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return 0;);
dirkx	0:355018f44c9f	877	LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return 0;);
dirkx	0:355018f44c9f	878
dirkx	0:355018f44c9f	879	if ((buf == NULL) \|\| (dataptr == NULL) \|\| (buf->tot_len < len)) {
dirkx	0:355018f44c9f	880	return ERR_ARG;
dirkx	0:355018f44c9f	881	}
dirkx	0:355018f44c9f	882
dirkx	0:355018f44c9f	883	/* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
dirkx	0:355018f44c9f	884	for(p = buf; total_copy_len != 0; p = p->next) {
dirkx	0:355018f44c9f	885	LWIP_ASSERT("pbuf_take: invalid pbuf", p != NULL);
dirkx	0:355018f44c9f	886	buf_copy_len = total_copy_len;
dirkx	0:355018f44c9f	887	if (buf_copy_len > p->len) {
dirkx	0:355018f44c9f	888	/* this pbuf cannot hold all remaining data */
dirkx	0:355018f44c9f	889	buf_copy_len = p->len;
dirkx	0:355018f44c9f	890	}
dirkx	0:355018f44c9f	891	/* copy the necessary parts of the buffer */
dirkx	0:355018f44c9f	892	MEMCPY(p->payload, &((char*)dataptr)[copied_total], buf_copy_len);
dirkx	0:355018f44c9f	893	total_copy_len -= buf_copy_len;
dirkx	0:355018f44c9f	894	copied_total += buf_copy_len;
dirkx	0:355018f44c9f	895	}
dirkx	0:355018f44c9f	896	LWIP_ASSERT("did not copy all data", total_copy_len == 0 && copied_total == len);
dirkx	0:355018f44c9f	897	return ERR_OK;
dirkx	0:355018f44c9f	898	}
dirkx	0:355018f44c9f	899
dirkx	0:355018f44c9f	900	/**
dirkx	0:355018f44c9f	901	* Creates a single pbuf out of a queue of pbufs.
dirkx	0:355018f44c9f	902	*
dirkx	0:355018f44c9f	903	* @remark: The source pbuf 'p' is not freed by this function because that can
dirkx	0:355018f44c9f	904	* be illegal in some places!
dirkx	0:355018f44c9f	905	*
dirkx	0:355018f44c9f	906	* @param p the source pbuf
dirkx	0:355018f44c9f	907	* @param layer pbuf_layer of the new pbuf
dirkx	0:355018f44c9f	908	*
dirkx	0:355018f44c9f	909	* @return a new, single pbuf (p->next is NULL)
dirkx	0:355018f44c9f	910	* or the old pbuf if allocation fails
dirkx	0:355018f44c9f	911	*/
dirkx	0:355018f44c9f	912	struct pbuf*
dirkx	0:355018f44c9f	913	pbuf_coalesce(struct pbuf *p, pbuf_layer layer)
dirkx	0:355018f44c9f	914	{
dirkx	0:355018f44c9f	915	struct pbuf *q;
dirkx	0:355018f44c9f	916	err_t err;
dirkx	0:355018f44c9f	917	if (p->next == NULL) {
dirkx	0:355018f44c9f	918	return p;
dirkx	0:355018f44c9f	919	}
dirkx	0:355018f44c9f	920	q = pbuf_alloc(layer, p->tot_len, PBUF_RAM);
dirkx	0:355018f44c9f	921	if (q == NULL) {
dirkx	0:355018f44c9f	922	/* @todo: what do we do now? */
dirkx	0:355018f44c9f	923	return p;
dirkx	0:355018f44c9f	924	}
dirkx	0:355018f44c9f	925	err = pbuf_copy(q, p);
dirkx	0:355018f44c9f	926	LWIP_ASSERT("pbuf_copy failed", err == ERR_OK);
dirkx	0:355018f44c9f	927	pbuf_free(p);
dirkx	0:355018f44c9f	928	return q;
dirkx	0:355018f44c9f	929	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	21 Jul 2010
Imports:	99
Forks:	0
Commits:	6
Dependents:	0
Dependencies:	1
Followers:	8

lwip/core/pbuf.c@5:8e53abda9900, 2010-08-14 (annotated)

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