[ospfd] discount IP header size from a new LSA pkt

This commit is contained in:
Dmitry Tejblum 2009-06-24 20:14:30 +04:00 committed by Denis Ovsienko
parent 014b670e02
commit c9035ccd13

View File

@ -2869,7 +2869,7 @@ ospf_make_ls_upd (struct ospf_interface *oi, struct list *update, struct stream
{
struct ospf_lsa *lsa;
struct listnode *node;
u_int16_t length = OSPF_LS_UPD_MIN_SIZE;
u_int16_t length = 0;
unsigned int size_noauth;
unsigned long delta = stream_get_endp (s);
unsigned long pp;
@ -2880,6 +2880,7 @@ ospf_make_ls_upd (struct ospf_interface *oi, struct list *update, struct stream
pp = stream_get_endp (s);
stream_forward_endp (s, OSPF_LS_UPD_MIN_SIZE);
length += OSPF_LS_UPD_MIN_SIZE;
/* Calculate amount of packet usable for data. */
size_noauth = stream_get_size(s) - ospf_packet_authspace(oi);
@ -3298,7 +3299,6 @@ ospf_ls_upd_packet_new (struct list *update, struct ospf_interface *oi)
else
size = oi->ifp->mtu;
/* XXX Should this be - sizeof(struct ip)?? -gdt */
if (size > OSPF_MAX_PACKET_SIZE)
{
zlog_warn ("ospf_ls_upd_packet_new: oversized LSA id:%s too big,"
@ -3310,7 +3310,16 @@ ospf_ls_upd_packet_new (struct list *update, struct ospf_interface *oi)
return NULL;
}
return ospf_packet_new (size);
/* IP header is built up separately by ospf_write(). This means, that we must
* reduce the "affordable" size just calculated by length of an IP header.
* This makes sure, that even if we manage to fill the payload with LSA data
* completely, the final packet (our data plus IP header) still fits into
* outgoing interface MTU. This correction isn't really meaningful for an
* oversized LSA, but for consistency the correction is done for both cases.
*
* P.S. OSPF_MAX_PACKET_SIZE above already includes IP header size
*/
return ospf_packet_new (size - sizeof (struct ip));
}
static void