*/
#include <linux/ip.h>
#include <linux/module.h>
+#include <linux/percpu.h>
#include <linux/route.h>
#include <linux/skbuff.h>
+#include <linux/notifier.h>
#include <net/checksum.h>
#include <net/icmp.h>
#include <net/ip.h>
# define WITH_IPV6 1
#endif
+struct xt_tee_priv {
+ struct notifier_block notifier;
+ struct xt_tee_tginfo *tginfo;
+ int oif;
+};
+
static const union nf_inet_addr tee_zero_address;
+static DEFINE_PER_CPU(bool, tee_active);
static struct net *pick_net(struct sk_buff *skb)
{
return &init_net;
}
-static bool tee_tg_route_oif(struct flowi *f, struct net *net,
- const struct xt_tee_tginfo *info)
-{
- const struct net_device *dev;
-
- if (*info->oif != '\0')
- return true;
- dev = dev_get_by_name(net, info->oif);
- if (dev == NULL)
- return false;
- f->oif = dev->ifindex;
- return true;
-}
-
static bool
tee_tg_route4(struct sk_buff *skb, const struct xt_tee_tginfo *info)
{
struct flowi fl;
memset(&fl, 0, sizeof(fl));
- if (!tee_tg_route_oif(&fl, net, info))
- return false;
+ if (info->priv) {
+ if (info->priv->oif == -1)
+ return false;
+ fl.oif = info->priv->oif;
+ }
fl.nl_u.ip4_u.daddr = info->gw.ip;
fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
fl.nl_u.ip4_u.scope = RT_SCOPE_UNIVERSE;
if (ip_route_output_key(net, &rt, &fl) != 0)
return false;
- dst_release(skb_dst(skb));
- skb_dst_set(skb, &rt->u.dst);
- skb->dev = rt->u.dst.dev;
+ skb_dst_drop(skb);
+ skb_dst_set(skb, &rt->dst);
+ skb->dev = rt->dst.dev;
skb->protocol = htons(ETH_P_IP);
return true;
}
static unsigned int
-tee_tg4(struct sk_buff *skb, const struct xt_target_param *par)
+tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_tee_tginfo *info = par->targinfo;
struct iphdr *iph;
+ if (percpu_read(tee_active))
+ return XT_CONTINUE;
/*
* Copy the skb, and route the copy. Will later return %XT_CONTINUE for
* the original skb, which should continue on its way as if nothing has
--iph->ttl;
ip_send_check(iph);
- /*
- * Xtables is not reentrant currently, so a choice has to be made:
- * 1. return absolute verdict for the original and let the cloned
- * packet travel through the chains
- * 2. let the original continue travelling and not pass the clone
- * to Xtables.
- * #2 is chosen. Normally, we would use ip_local_out for the clone.
- * Because iph->check is already correct and we don't pass it to
- * Xtables anyway, a shortcut to dst_output [forwards to ip_output] can
- * be taken. %IPSKB_REROUTED needs to be set so that ip_output does not
- * invoke POSTROUTING on the cloned packet.
- */
- IPCB(skb)->flags |= IPSKB_REROUTED;
- if (tee_tg_route4(skb, info))
- ip_output(skb);
- else
+ if (tee_tg_route4(skb, info)) {
+ percpu_write(tee_active, true);
+ ip_local_out(skb);
+ percpu_write(tee_active, false);
+ } else {
kfree_skb(skb);
-
+ }
return XT_CONTINUE;
}
struct flowi fl;
memset(&fl, 0, sizeof(fl));
- if (!tee_tg_route_oif(&fl, net, info))
- return false;
+ if (info->priv) {
+ if (info->priv->oif == -1)
+ return false;
+ fl.oif = info->priv->oif;
+ }
fl.nl_u.ip6_u.daddr = info->gw.in6;
fl.nl_u.ip6_u.flowlabel = ((iph->flow_lbl[0] & 0xF) << 16) |
(iph->flow_lbl[1] << 8) | iph->flow_lbl[2];
if (dst == NULL)
return false;
- dst_release(skb_dst(skb));
+ skb_dst_drop(skb);
skb_dst_set(skb, dst);
skb->dev = dst->dev;
skb->protocol = htons(ETH_P_IPV6);
}
static unsigned int
-tee_tg6(struct sk_buff *skb, const struct xt_target_param *par)
+tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_tee_tginfo *info = par->targinfo;
+ if (percpu_read(tee_active))
+ return XT_CONTINUE;
skb = pskb_copy(skb, GFP_ATOMIC);
if (skb == NULL)
return XT_CONTINUE;
struct ipv6hdr *iph = ipv6_hdr(skb);
--iph->hop_limit;
}
- IP6CB(skb)->flags |= IP6SKB_REROUTED;
- if (tee_tg_route6(skb, info))
- ip6_output(skb);
- else
+ if (tee_tg_route6(skb, info)) {
+ percpu_write(tee_active, true);
+ ip6_local_out(skb);
+ percpu_write(tee_active, false);
+ } else {
kfree_skb(skb);
-
+ }
return XT_CONTINUE;
}
#endif /* WITH_IPV6 */
+static int tee_netdev_event(struct notifier_block *this, unsigned long event,
+ void *ptr)
+{
+ struct net_device *dev = ptr;
+ struct xt_tee_priv *priv;
+
+ priv = container_of(this, struct xt_tee_priv, notifier);
+ switch (event) {
+ case NETDEV_REGISTER:
+ if (!strcmp(dev->name, priv->tginfo->oif))
+ priv->oif = dev->ifindex;
+ break;
+ case NETDEV_UNREGISTER:
+ if (dev->ifindex == priv->oif)
+ priv->oif = -1;
+ break;
+ case NETDEV_CHANGENAME:
+ if (!strcmp(dev->name, priv->tginfo->oif))
+ priv->oif = dev->ifindex;
+ else if (dev->ifindex == priv->oif)
+ priv->oif = -1;
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
static int tee_tg_check(const struct xt_tgchk_param *par)
{
- const struct xt_tee_tginfo *info = par->targinfo;
+ struct xt_tee_tginfo *info = par->targinfo;
+ struct xt_tee_priv *priv;
- if (info->oif[sizeof(info->oif)-1] != '\0')
- return -EINVAL;
/* 0.0.0.0 and :: not allowed */
- return (memcmp(&info->gw, &tee_zero_address,
- sizeof(tee_zero_address)) == 0) ? -EINVAL : 0;
+ if (memcmp(&info->gw, &tee_zero_address,
+ sizeof(tee_zero_address)) == 0)
+ return -EINVAL;
+
+ if (info->oif[0]) {
+ if (info->oif[sizeof(info->oif)-1] != '\0')
+ return -EINVAL;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (priv == NULL)
+ return -ENOMEM;
+
+ priv->tginfo = info;
+ priv->oif = -1;
+ priv->notifier.notifier_call = tee_netdev_event;
+ info->priv = priv;
+
+ register_netdevice_notifier(&priv->notifier);
+ } else
+ info->priv = NULL;
+
+ return 0;
+}
+
+static void tee_tg_destroy(const struct xt_tgdtor_param *par)
+{
+ struct xt_tee_tginfo *info = par->targinfo;
+
+ if (info->priv) {
+ unregister_netdevice_notifier(&info->priv->notifier);
+ kfree(info->priv);
+ }
}
static struct xt_target tee_tg_reg[] __read_mostly = {
.target = tee_tg4,
.targetsize = sizeof(struct xt_tee_tginfo),
.checkentry = tee_tg_check,
+ .destroy = tee_tg_destroy,
.me = THIS_MODULE,
},
#ifdef WITH_IPV6
.target = tee_tg6,
.targetsize = sizeof(struct xt_tee_tginfo),
.checkentry = tee_tg_check,
+ .destroy = tee_tg_destroy,
.me = THIS_MODULE,
},
#endif