static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
__be16 proto)
{
struct ip_tunnel_info *tun_info;
const struct ip_tunnel_key *key;
struct rtable *rt = NULL;
struct flowi4 fl;
int min_headroom;
int tunnel_hlen;
__be16 df, flags;
bool use_cache;
int err;
tun_info = skb_tunnel_info(skb);
if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
ip_tunnel_info_af(tun_info) != AF_INET))
goto err_free_skb;
key = &tun_info->key;
use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
if (use_cache)
rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl.saddr);
if (!rt) {
rt = gre_get_rt(skb, dev, &fl, key);
if (IS_ERR(rt))
goto err_free_skb;
if (use_cache)
dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
fl.saddr);
}
tunnel_hlen = gre_calc_hlen(key->tun_flags);
min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
+ tunnel_hlen + sizeof(struct iphdr);
if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
int head_delta = SKB_DATA_ALIGN(min_headroom -
skb_headroom(skb) +
16);
err = pskb_expand_head(skb, max_t(int, head_delta, 0),
0, GFP_ATOMIC);
if (unlikely(err))
goto err_free_rt;
}
static struct rtable *prepare_fb_xmit(struct sk_buff *skb,
struct net_device *dev,
struct flowi4 *fl,
int tunnel_hlen)
{
struct ip_tunnel_info *tun_info;
const struct ip_tunnel_key *key;
struct rtable *rt = NULL;
int min_headroom;
bool use_cache;
int err;
tun_info = skb_tunnel_info(skb);
key = &tun_info->key;
use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
if (use_cache)
rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl->saddr);
if (!rt) {
rt = gre_get_rt(skb, dev, fl, key);
if (IS_ERR(rt))
goto err_free_skb;
if (use_cache)
dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
fl->saddr);
}
min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
+ tunnel_hlen + sizeof(struct iphdr);
if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
int head_delta = SKB_DATA_ALIGN(min_headroom -
skb_headroom(skb) +
16);
err = pskb_expand_head(skb, max_t(int, head_delta, 0),
0, GFP_ATOMIC);
if (unlikely(err))
goto err_free_rt;
}