int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
struct ip_comp_hdr *ipch;
struct ipcomp_data *ipcd = x->data;
if (skb->len < ipcd->threshold) {
goto out_ok;
}
if (skb_linearize_cow(skb))
goto out_ok;
err = ipcomp_compress(x, skb);
if (err) {
goto out_ok;
}
ipch = ip_comp_hdr(skb);
ipch->nexthdr = *skb_mac_header(skb);
ipch->flags = 0;
ipch->cpi = htons((u16 )ntohl(x->id.spi));
*skb_mac_header(skb) = IPPROTO_COMP;
out_ok:
skb_push(skb, -skb_network_offset(skb));
return 0;
}
static int ipcomp_output(struct sk_buff *skb)
{
int err;
struct dst_entry *dst = skb->dst;
struct xfrm_state *x = dst->xfrm;
struct iphdr *iph, *top_iph;
struct ip_comp_hdr *ipch;
struct ipcomp_data *ipcd = x->data;
union {
struct iphdr iph;
char buf[60];
} tmp_iph;
int hdr_len = 0;
if (skb->ip_summed == CHECKSUM_HW && skb_checksum_help(skb) == NULL) {
err = -EINVAL;
goto error_nolock;
}
spin_lock_bh(&x->lock);
err = xfrm_check_output(x, skb, AF_INET);
if (err)
goto error;
/* Don't bother compressing */
if (!x->props.mode) {
iph = skb->nh.iph;
hdr_len = iph->ihl * 4;
}
if ((skb->len - hdr_len) < ipcd->threshold) {
if (x->props.mode) {
ipcomp_tunnel_encap(x, skb);
iph = skb->nh.iph;
iph->protocol = IPPROTO_IPIP;
ip_send_check(iph);
}
goto out_ok;
}
if (x->props.mode)
ipcomp_tunnel_encap(x, skb);
if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
skb_linearize(skb, GFP_ATOMIC) != 0) {
err = -ENOMEM;
goto error;
}
err = ipcomp_compress(x, skb);
if (err) {
if (err == -EMSGSIZE) {
if (x->props.mode) {
iph = skb->nh.iph;
iph->protocol = IPPROTO_IPIP;
ip_send_check(iph);
}
goto out_ok;
}
goto error;
}
/* Install ipcomp header, convert into ipcomp datagram. */
iph = skb->nh.iph;
memcpy(&tmp_iph, iph, iph->ihl * 4);
top_iph = (struct iphdr *)skb_push(skb, sizeof(struct ip_comp_hdr));
memcpy(top_iph, &tmp_iph, iph->ihl * 4);
iph = top_iph;
if (x->props.mode && (x->props.flags & XFRM_STATE_NOECN))
IP_ECN_clear(iph);
iph->tot_len = htons(skb->len);
iph->protocol = IPPROTO_COMP;
iph->check = 0;
ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4);
ipch->nexthdr = x->props.mode ? IPPROTO_IPIP : tmp_iph.iph.protocol;
ipch->flags = 0;
ipch->cpi = htons((u16 )ntohl(x->id.spi));
ip_send_check(iph);
skb->nh.raw = skb->data;
out_ok:
x->curlft.bytes += skb->len;
x->curlft.packets++;
spin_unlock_bh(&x->lock);
if ((skb->dst = dst_pop(dst)) == NULL) {
err = -EHOSTUNREACH;
goto error_nolock;
}
err = NET_XMIT_BYPASS;
out_exit:
return err;
error:
spin_unlock_bh(&x->lock);
error_nolock:
kfree_skb(skb);
goto out_exit;
}
