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Fixing bug #1903 with a new pbuf_realloc() that respects mixed-type chains.

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likewise 2003-03-26 13:30:38 +00:00
parent ab630b2875
commit fd0d94af44
1 changed files with 77 additions and 12 deletions
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89
src/core/pbuf.c
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@ -34,14 +34,8 @@
*
*/
/*-----------------------------------------------------------------------------------*/
/* pbuf.c
*
* Functions for the manipulation of pbufs. The pbufs holds all packets in the
* system.
*
*/
/*-----------------------------------------------------------------------------------*/
#define NEW_PBUF_REALLOC 1 /* should fix bug #1903 */
#include "lwip/opt.h"
#include "lwip/stats.h"
@ -404,18 +398,86 @@ pbuf_refresh(void)
sys_sem_signal(pbuf_pool_free_sem); \
} while(0)
#endif /* SYS_LIGHTWEIGHT_PROT */
/*-----------------------------------------------------------------------------------*/
/* pbuf_realloc:
/**
* Shrink a pbuf chain to a certain size.
*
* Reallocates the memory for a pbuf. If the pbuf is in ROM, this as
* simple as to adjust the ->tot_len and ->len fields. If the pbuf is
* @param p pbuf to shrink.
* @param size new size
* If the pbuf is in ROM, only the ->tot_len and ->len fields are adjusted.
* If the chain
* a pbuf chain, as it might be with both pbufs in dynamically
* allocated RAM and for pbufs from the pbuf pool, we have to step
* through the chain until we find the new endpoint in the pbuf chain.
* Then the pbuf that is right on the endpoint is resized and any
* further pbufs on the chain are deallocated.
* @bug #1903
*/
/*-----------------------------------------------------------------------------------*/
#if NEW_PBUF_REALLOC
void
pbuf_realloc(struct pbuf *p, u16_t new_len)
{
struct pbuf *q, *r;
u16_t rem_len; /* remaining length */
LWIP_ASSERT("pbuf_realloc: sane p->flags", p->flags == PBUF_FLAG_POOL ||
p->flags == PBUF_FLAG_ROM ||
p->flags == PBUF_FLAG_RAM ||
p->flags == PBUF_FLAG_REF);
if (new_len >= p->tot_len) {
/** enlarging not yet supported */
return;
}
/* first, step over any pbufs that should remain in the chain */
rem_len = new_len;
q = p;
/* this pbuf should be kept? */
while (rem_len > q->len) {
/* decrease remaining length by pbuf length */
rem_len -= q->len;
q = q->next;
}
/* { we have now reached the new last pbuf } */
/* { rem_len == desired length for pbuf q } */
/* shrink allocated memory for PBUF_RAM */
/* (other types merely adjust their length fields */
if (q->flags == PBUF_FLAG_RAM) {
/* reallocate and adjust the length of the pbuf that will be split */
mem_realloc(q, (u8_t *)q->payload - (u8_t *)q + rem_len);
}
q->len = rem_len;
q->tot_len = q->len;
/* deallocate any left over pbufs */
/* remember next pbuf in chain */
r = q->next;
/* q is last packet in chain */
q->next = NULL;
/* first pbuf to be dealloced */
q = r;
/* any pbuf left? */
while(q != NULL) {
/* remember next pbuf in chain */
r = q->next;
/* deallocate pbuf */
if (q->flags == PBUF_FLAG_RAM) {
pbuf_free(q);
} else if ((q->flags == PBUF_FLAG_ROM) || (q->flags == PBUF_FLAG_REF)) {
PBUF_POOL_FREE(q);
} else if (q->flags == PBUF_FLAG_POOL) {
PBUF_POOL_FREE(q);
}
q = r;
}
pbuf_refresh();
}
#else /* pbuf_realloc() of CVS version 1.23 */
void
pbuf_realloc(struct pbuf *p, u16_t size)
{
@ -487,6 +549,8 @@ pbuf_realloc(struct pbuf *p, u16_t size)
pbuf_refresh();
}
#endif
/**
* Decreases the header size by the given amount.
*
@ -789,3 +853,4 @@ pbuf_unref(struct pbuf *f)
return top;
}