static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst,
bool fastopen_clear)
{
u32 val;
tm->tcpm_stamp = jiffies;
val = 0;
if (dst_metric_locked(dst, RTAX_RTT))
val |= 1 << TCP_METRIC_RTT;
if (dst_metric_locked(dst, RTAX_RTTVAR))
val |= 1 << TCP_METRIC_RTTVAR;
if (dst_metric_locked(dst, RTAX_SSTHRESH))
val |= 1 << TCP_METRIC_SSTHRESH;
if (dst_metric_locked(dst, RTAX_CWND))
val |= 1 << TCP_METRIC_CWND;
if (dst_metric_locked(dst, RTAX_REORDERING))
val |= 1 << TCP_METRIC_REORDERING;
tm->tcpm_lock = val;
tm->tcpm_vals[TCP_METRIC_RTT] = dst_metric_raw(dst, RTAX_RTT);
tm->tcpm_vals[TCP_METRIC_RTTVAR] = dst_metric_raw(dst, RTAX_RTTVAR);
tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH);
tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND);
tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING);
tm->tcpm_ts = 0;
tm->tcpm_ts_stamp = 0;
if (fastopen_clear) {
tm->tcpm_fastopen.mss = 0;
tm->tcpm_fastopen.syn_loss = 0;
tm->tcpm_fastopen.cookie.len = 0;
}
}
/*
* The decnet standards don't impose a particular minimum mtu, what they
* do insist on is that the routing layer accepts a datagram of at least
* 230 bytes long. Here we have to subtract the routing header length from
* 230 to get the minimum acceptable mtu. If there is no neighbour, then we
* assume the worst and use a long header size.
*
* We update both the mtu and the advertised mss (i.e. the segment size we
* advertise to the other end).
*/
static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
{
u32 min_mtu = 230;
struct dn_dev *dn = dst->neighbour ?
(struct dn_dev *)dst->neighbour->dev->dn_ptr : NULL;
if (dn && dn->use_long == 0)
min_mtu -= 6;
else
min_mtu -= 21;
if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= min_mtu) {
if (!(dst_metric_locked(dst, RTAX_MTU))) {
dst->metrics[RTAX_MTU-1] = mtu;
dst_set_expires(dst, dn_rt_mtu_expires);
}
if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
if (dst->metrics[RTAX_ADVMSS-1] > mss)
dst->metrics[RTAX_ADVMSS-1] = mss;
}
}
}
static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
{
unsigned int mtu;
struct inet6_dev *idev;
if (dst_metric_locked(dst, RTAX_MTU)) {
mtu = dst_metric_raw(dst, RTAX_MTU);
if (mtu)
return mtu;
}
mtu = IPV6_MIN_MTU;
rcu_read_lock();
idev = __in6_dev_get(dst->dev);
if (idev)
mtu = idev->cnf.mtu6;
rcu_read_unlock();
return mtu;
}
