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ggsn: Remove magic numbers from pco_contains_proto() 

Let's remove some magic numbers and use a data structure to describe
the PCO element header.

Change-Id: I9871ffced677320aa82438332bfdb951ab129f04
This commit is contained in:
Harald Welte 2019-04-10 15:15:26 +02:00
parent ffa227307c
commit df404c4296
1 changed files with 11 additions and 6 deletions
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17
ggsn/ggsn.c
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@ -462,18 +462,23 @@ enum pco_protocols {
PCO_P_REL_DATA_SVC = 0x0018,
};
struct pco_element {
uint16_t protocol_id; /* network byte order */
uint8_t length; /* length of data below */
uint8_t data[0];
} __attribute__((packed));
/* determine if PCO contains given protocol */
static uint8_t *pco_contains_proto(struct ul255_t *pco, size_t offset, uint16_t prot, size_t prot_minlen)
{
uint8_t *cur = pco->v + 1 + offset;
uint8_t *cur = pco->v + 1 /*length*/ + offset;
/* iterate over PCO and check if protocol contained */
while (cur + 3 <= pco->v + pco->l) {
uint16_t cur_prot = osmo_load16be(cur);
uint8_t cur_len = cur[2];
if (cur_prot == prot && cur_len >= prot_minlen)
while (cur + sizeof(struct pco_element) <= pco->v + pco->l) {
const struct pco_element *elem = (const struct pco_element *)cur;
if (ntohs(elem->protocol_id) == prot && elem->length >= prot_minlen)
return cur;
cur += cur_len + 3;
cur += elem->length + sizeof(struct pco_element);
}
return NULL;
}