eigrpd: Correctly set the mtu for eigrp packets sent

This version of eigrp pre-calculated the eigrp metric
to be a default of 1500 bytes, but unfortunately it
had entered the byte order wrong.

Modify the code to properly set the byte order
according to the eigrp rfc as well as actually
read in and transmit the mtu of the interface
instead of hard coding it to 1500 bytes.

Fixes: #7986
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
This commit is contained in:
Donald Sharp 2021-01-31 08:32:15 -05:00
parent 127949a9af
commit 7c6ff2c54f
2 changed files with 16 additions and 4 deletions

View File

@ -229,6 +229,20 @@ void eigrp_del_if_params(struct eigrp_if_params *eip)
free(eip->auth_keychain); free(eip->auth_keychain);
} }
/*
* Set the network byte order of the 3 bytes we send
* of the mtu of the link.
*/
static void eigrp_mtu_convert(struct eigrp_metrics *metric, uint32_t host_mtu)
{
uint32_t network_mtu = htonl(host_mtu);
uint8_t *nm = (uint8_t *)&network_mtu;
metric->mtu[0] = nm[1];
metric->mtu[1] = nm[2];
metric->mtu[2] = nm[3];
}
int eigrp_if_up(struct eigrp_interface *ei) int eigrp_if_up(struct eigrp_interface *ei)
{ {
struct eigrp_prefix_descriptor *pe; struct eigrp_prefix_descriptor *pe;
@ -256,9 +270,7 @@ int eigrp_if_up(struct eigrp_interface *ei)
metric.delay = eigrp_delay_to_scaled(ei->params.delay); metric.delay = eigrp_delay_to_scaled(ei->params.delay);
metric.load = ei->params.load; metric.load = ei->params.load;
metric.reliability = ei->params.reliability; metric.reliability = ei->params.reliability;
metric.mtu[0] = 0xDC; eigrp_mtu_convert(&metric, ei->ifp->mtu);
metric.mtu[1] = 0x05;
metric.mtu[2] = 0x00;
metric.hop_count = 0; metric.hop_count = 0;
metric.flags = 0; metric.flags = 0;
metric.tag = 0; metric.tag = 0;

View File

@ -40,7 +40,7 @@
struct eigrp_metrics { struct eigrp_metrics {
uint32_t delay; uint32_t delay;
uint32_t bandwidth; uint32_t bandwidth;
unsigned char mtu[3]; uint8_t mtu[3];
uint8_t hop_count; uint8_t hop_count;
uint8_t reliability; uint8_t reliability;
uint8_t load; uint8_t load;