41 lines
1.1 KiB
C
41 lines
1.1 KiB
C
#include <qse/dhcp/dhcp6msg.h>
|
|
#include <qse/cmn/hton.h>
|
|
|
|
qse_dhcp6_opt_hdr_t* qse_dhcp6_find_option (const qse_dhcp6_pktinf_t* pkt, int code)
|
|
{
|
|
qse_dhcp6_opt_hdr_t* opt;
|
|
qse_size_t rem, opt_len;
|
|
|
|
if (pkt->len < QSE_SIZEOF(qse_dhcp6_pkt_hdr_t)) return QSE_NULL;
|
|
|
|
if (pkt->hdr->msgtype == QSE_DHCP6_MSG_RELAYFORW || pkt->hdr->msgtype == QSE_DHCP6_MSG_RELAYREPL)
|
|
{
|
|
if (pkt->len < QSE_SIZEOF(qse_dhcp6_relay_hdr_t)) return QSE_NULL;
|
|
|
|
rem = pkt->len - QSE_SIZEOF(qse_dhcp6_relay_hdr_t);
|
|
opt = (qse_dhcp6_opt_hdr_t*)(((qse_dhcp6_relay_hdr_t*)pkt->hdr) + 1);
|
|
}
|
|
else
|
|
{
|
|
rem = pkt->len - QSE_SIZEOF(qse_dhcp6_pkt_hdr_t);
|
|
opt = (qse_dhcp6_opt_hdr_t*)(pkt->hdr + 1);
|
|
}
|
|
|
|
while (rem >= QSE_SIZEOF(qse_dhcp6_opt_hdr_t))
|
|
{
|
|
if (qse_ntoh16(opt->code) == code)
|
|
{
|
|
if (rem - QSE_SIZEOF(qse_dhcp6_opt_hdr_t) < qse_ntoh16(opt->len)) return QSE_NULL; /* probably the packet is ill-formed */
|
|
return opt;
|
|
}
|
|
|
|
opt_len = QSE_SIZEOF(qse_dhcp6_opt_hdr_t) + qse_ntoh16(opt->len);
|
|
if (rem < opt_len) break;
|
|
rem -= opt_len;
|
|
opt = (qse_dhcp6_opt_hdr_t*)((qse_uint8_t*)(opt + 1) + qse_ntoh16(opt->len));
|
|
|
|
}
|
|
|
|
return QSE_NULL;
|
|
}
|