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likewise 2004-05-05 14:12:28 +00:00
parent 8bb3cab9d2
commit 5e13b9528d
2 changed files with 32 additions and 28 deletions
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47
src/core/pbuf.c
View File

@ -460,25 +460,27 @@ pbuf_realloc(struct pbuf *p, u16_t new_len)
* PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so * PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so
* the call will fail. A check is made that the increase in header size does * the call will fail. A check is made that the increase in header size does
* not move the payload pointer in front of the start of the buffer. * not move the payload pointer in front of the start of the buffer.
* @return 1 on failure, 0 on success. * @return non-zero on failure, zero on success.
* *
* @note May not be called on a packet queue.
*/ */
u8_t u8_t
pbuf_header(struct pbuf *p, s16_t header_size) pbuf_header(struct pbuf *p, s16_t header_size_increment)
{ {
void *payload; void *payload;
LWIP_ASSERT("p != NULL", p != NULL);
if ((header_size_increment == 0) || (p == NULL)) return 0;
/* remember current payload pointer */ /* remember current payload pointer */
payload = p->payload; payload = p->payload;
/* pbuf types containing payloads? */ /* pbuf types containing payloads? */
if (p->flags == PBUF_FLAG_RAM || p->flags == PBUF_FLAG_POOL) { if (p->flags == PBUF_FLAG_RAM || p->flags == PBUF_FLAG_POOL) {
/* set new payload pointer */ /* set new payload pointer */
p->payload = (u8_t *)p->payload - header_size; p->payload = (u8_t *)p->payload - header_size_increment;
/* boundary check fails? */ /* boundary check fails? */
if ((u8_t *)p->payload < (u8_t *)p + sizeof(struct pbuf)) { if ((u8_t *)p->payload < (u8_t *)p + sizeof(struct pbuf)) {
LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_header: failed as %p < %p\n", LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
(u8_t *)p->payload, (u8_t *)p->payload,
(u8_t *)p + sizeof(struct pbuf)) );\ (u8_t *)p + sizeof(struct pbuf)) );\
/* restore old payload pointer */ /* restore old payload pointer */
@ -486,22 +488,24 @@ pbuf_header(struct pbuf *p, s16_t header_size)
/* bail out unsuccesfully */ /* bail out unsuccesfully */
return 1; return 1;
} }
/* pbuf types refering to payloads? */ /* pbuf types refering to external payloads? */
} else if (p->flags == PBUF_FLAG_REF || p->flags == PBUF_FLAG_ROM) { } else if (p->flags == PBUF_FLAG_REF || p->flags == PBUF_FLAG_ROM) {
/* hide a header in the payload? */ /* hide a header in the payload? */
if ((header_size < 0) && (header_size - p->len <= 0)) { if ((header_size_increment < 0) && (header_size_increment - p->len <= 0)) {
/* increase payload pointer */ /* increase payload pointer */
p->payload = (u8_t *)p->payload - header_size; p->payload = (u8_t *)p->payload - header_size_increment;
} else { } else {
/* cannot expand payload to front (yet!) /* cannot expand payload to front (yet!)
* bail out unsuccesfully */ * bail out unsuccesfully */
return 1; return 1;
} }
} }
LWIP_DEBUGF( PBUF_DEBUG, ("pbuf_header: old %p new %p (%d)\n", (void *)payload, (void *)p->payload, header_size) );
/* modify pbuf length fields */ /* modify pbuf length fields */
p->len += header_size; p->len += header_size_increment;
p->tot_len += header_size; p->tot_len += header_size_increment;
LWIP_DEBUGF( PBUF_DEBUG, ("pbuf_header: old %p new %p (%d)\n",
(void *)payload, (void *)p->payload, header_size_increment));
return 0; return 0;
} }
@ -510,8 +514,8 @@ pbuf_header(struct pbuf *p, s16_t header_size)
* Dereference a pbuf chain or queue and deallocate any no-longer-used * Dereference a pbuf chain or queue and deallocate any no-longer-used
* pbufs at the head of this chain or queue. * pbufs at the head of this chain or queue.
* *
* Decrements the pbuf reference count. If it reaches * Decrements the pbuf reference count. If it reaches zero, the pbuf is
* zero, the pbuf is deallocated. * deallocated.
* *
* For a pbuf chain, this is repeated for each pbuf in the chain, * For a pbuf chain, this is repeated for each pbuf in the chain,
* up to the first pbuf which has a non-zero reference count after * up to the first pbuf which has a non-zero reference count after
@ -522,7 +526,7 @@ pbuf_header(struct pbuf *p, s16_t header_size)
* @return the number of pbufs that were de-allocated * @return the number of pbufs that were de-allocated
* from the head of the chain. * from the head of the chain.
* *
* @note MUST NOT be called on a packet queue. * @note MUST NOT be called on a packet queue (Not verified to work yet).
* @note the reference counter of a pbuf equals the number of pointers * @note the reference counter of a pbuf equals the number of pointers
* that refer to the pbuf (or into the pbuf). * that refer to the pbuf (or into the pbuf).
* *
@ -711,12 +715,15 @@ pbuf_chain(struct pbuf *h, struct pbuf *t)
* *
*/ */
void void
pbuf_queue(struct pbuf *p, struct pbuf *n) pbuf_queue(struct pbuf *q, struct pbuf *n)
{ {
struct pbuf *p;
/* programmer stupidity checks */
LWIP_ASSERT("p != NULL", p != NULL); LWIP_ASSERT("p != NULL", p != NULL);
LWIP_ASSERT("n != NULL", n != NULL); LWIP_ASSERT("n != NULL", n != NULL);
if ((p == NULL) || (n == NULL)) return; if ((p == NULL) || (n == NULL)) return;
p = q;
/* iterate through all packets on queue */ /* iterate through all packets on queue */
while (p->next != NULL) { while (p->next != NULL) {
/* be very picky about pbuf chain correctness */ /* be very picky about pbuf chain correctness */
@ -728,10 +735,10 @@ pbuf_queue(struct pbuf *p, struct pbuf *n)
/* make sure each packet is complete */ /* make sure each packet is complete */
LWIP_ASSERT("p->next != NULL", p->next != NULL); LWIP_ASSERT("p->next != NULL", p->next != NULL);
p = p->next; p = p->next;
/* { p->tot_len == p->len } => p is last pbuf of a packet */ /* { p->tot_len == p->len => p is last pbuf of a packet } */
} }
#endif #endif
/* { p->tot_len == p->len } => p is last pbuf of a packet */ /* { p->tot_len == p->len and p is last pbuf of a packet } */
/* proceed to next packet on queue */ /* proceed to next packet on queue */
if (p->next != NULL) p = p->next; if (p->next != NULL) p = p->next;
} }
@ -739,9 +746,11 @@ pbuf_queue(struct pbuf *p, struct pbuf *n)
* { p is last pbuf of last packet on queue } */ * { p is last pbuf of last packet on queue } */
/* chain last pbuf of queue with n */ /* chain last pbuf of queue with n */
p->next = n; p->next = n;
/* n is now referenced to one more time */ /* n is now referenced to by the (packet p in the) queue */
pbuf_ref(n); pbuf_ref(n);
LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_queue: referencing queued packet %p\n", (void *)n)); LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2,
("pbuf_queue: newly queued packet %p sits after packet %p in queue %p\n",
(void *)n, (void *)p, (void *)q));
} }
/** /**

13
src/include/lwip/pbuf.h
View File

@ -53,8 +53,8 @@ typedef enum {
PBUF_POOL PBUF_POOL
} pbuf_flag; } pbuf_flag;
/* Definitions for the pbuf flag field (these are not the flags that /* Definitions for the pbuf flag field. These are NOT the flags that
are passed to pbuf_alloc()). */ * are passed to pbuf_alloc(). */
#define PBUF_FLAG_RAM 0x00U /* Flags that pbuf data is stored in RAM */ #define PBUF_FLAG_RAM 0x00U /* Flags that pbuf data is stored in RAM */
#define PBUF_FLAG_ROM 0x01U /* Flags that pbuf data is stored in ROM */ #define PBUF_FLAG_ROM 0x01U /* Flags that pbuf data is stored in ROM */
#define PBUF_FLAG_POOL 0x02U /* Flags that the pbuf comes from the pbuf pool */ #define PBUF_FLAG_POOL 0x02U /* Flags that the pbuf comes from the pbuf pool */
@ -79,10 +79,10 @@ struct pbuf {
*/ */
u16_t tot_len; u16_t tot_len;
/* length of this buffer */ /** length of this buffer */
u16_t len; u16_t len;
/* flags telling the type of pbuf */ /** flags telling the type of pbuf, see PBUF_FLAG_ */
u16_t flags; u16_t flags;
/** /**
@ -94,11 +94,6 @@ struct pbuf {
}; };
/* pbuf_init():
Initializes the pbuf module. The num parameter determines how many
pbufs that should be allocated to the pbuf pool, and the size
parameter specifies the size of the data allocated to those. */
void pbuf_init(void); void pbuf_init(void);
struct pbuf *pbuf_alloc(pbuf_layer l, u16_t size, pbuf_flag flag); struct pbuf *pbuf_alloc(pbuf_layer l, u16_t size, pbuf_flag flag);