static void ip_tunnel_update(struct ip_tunnel_net *itn,
struct ip_tunnel *t,
struct net_device *dev,
struct ip_tunnel_parm *p,
bool set_mtu)
{
ip_tunnel_del(itn, t);
t->parms.iph.saddr = p->iph.saddr;
t->parms.iph.daddr = p->iph.daddr;
t->parms.i_key = p->i_key;
t->parms.o_key = p->o_key;
if (dev->type != ARPHRD_ETHER) {
memcpy(dev->dev_addr, &p->iph.saddr, 4);
memcpy(dev->broadcast, &p->iph.daddr, 4);
}
ip_tunnel_add(itn, t);
t->parms.iph.ttl = p->iph.ttl;
t->parms.iph.tos = p->iph.tos;
t->parms.iph.frag_off = p->iph.frag_off;
if (t->parms.link != p->link) {
int mtu;
t->parms.link = p->link;
mtu = ip_tunnel_bind_dev(dev);
if (set_mtu)
dev->mtu = mtu;
}
dst_cache_reset(&t->dst_cache);
netdev_state_change(dev);
}
void ip_tunnel_uninit(struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
struct net *net = tunnel->net;
struct ip_tunnel_net *itn;
itn = net_generic(net, tunnel->ip_tnl_net_id);
/* fb_tunnel_dev will be unregisted in net-exit call. */
if (itn->fb_tunnel_dev != dev)
ip_tunnel_del(itn, netdev_priv(dev));
dst_cache_reset(&tunnel->dst_cache);
}
static int ip_tunnel_bind_dev(struct net_device *dev)
{
struct net_device *tdev = NULL;
struct ip_tunnel *tunnel = netdev_priv(dev);
const struct iphdr *iph;
int hlen = LL_MAX_HEADER;
int mtu = ETH_DATA_LEN;
int t_hlen = tunnel->hlen + sizeof(struct iphdr);
iph = &tunnel->parms.iph;
/* Guess output device to choose reasonable mtu and needed_headroom */
if (iph->daddr) {
struct flowi4 fl4;
struct rtable *rt;
init_tunnel_flow(&fl4, iph->protocol, iph->daddr,
iph->saddr, tunnel->parms.o_key,
RT_TOS(iph->tos), tunnel->parms.link);
rt = ip_route_output_key(tunnel->net, &fl4);
if (!IS_ERR(rt)) {
tdev = rt->dst.dev;
ip_rt_put(rt);
}
if (dev->type != ARPHRD_ETHER)
dev->flags |= IFF_POINTOPOINT;
dst_cache_reset(&tunnel->dst_cache);
}
if (!tdev && tunnel->parms.link)
tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
if (tdev) {
hlen = tdev->hard_header_len + tdev->needed_headroom;
mtu = tdev->mtu;
}
dev->needed_headroom = t_hlen + hlen;
mtu -= (dev->hard_header_len + t_hlen);
if (mtu < 68)
mtu = 68;
return mtu;
}
