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ipv4: Generalize ip_do_redirect() and hook into new dst_ops->redirect.

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All of the redirect acceptance policy is now contained within.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2012-07-11 20:55:47 -07:00
parent 94206125c4
commit e47a185b31
2 changed files with 55 additions and 40 deletions
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1
include/net/dst_ops.h
View File

@ -25,6 +25,7 @@ struct dst_ops {
struct dst_entry * (*negative_advice)(struct dst_entry *);
void (*link_failure)(struct sk_buff *);
void (*update_pmtu)(struct dst_entry *dst, u32 mtu);
void (*redirect)(struct dst_entry *dst, struct sk_buff *skb);
int (*local_out)(struct sk_buff *skb);
struct neighbour * (*neigh_lookup)(const struct dst_entry *dst,
struct sk_buff *skb,

94
net/ipv4/route.c
View File

@ -149,6 +149,7 @@ static void ipv4_dst_destroy(struct dst_entry *dst);
static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
static void ipv4_link_failure(struct sk_buff *skb);
static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
static void ip_do_redirect(struct dst_entry *dst, struct sk_buff *skb);
static int rt_garbage_collect(struct dst_ops *ops);
static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
@ -179,6 +180,7 @@ static struct dst_ops ipv4_dst_ops = {
.negative_advice = ipv4_negative_advice,
.link_failure = ipv4_link_failure,
.update_pmtu = ip_rt_update_pmtu,
.redirect = ip_do_redirect,
.local_out = __ip_local_out,
.neigh_lookup = ipv4_neigh_lookup,
};
@ -1271,42 +1273,18 @@ static void rt_del(unsigned int hash, struct rtable *rt)
spin_unlock_bh(rt_hash_lock_addr(hash));
}
static void ip_do_redirect(struct rtable *rt, __be32 old_gw, __be32 new_gw)
{
struct neighbour *n;
if (rt->rt_gateway != old_gw)
return;
n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
if (n) {
if (!(n->nud_state & NUD_VALID)) {
neigh_event_send(n, NULL);
} else {
rt->rt_gateway = new_gw;
rt->rt_flags |= RTCF_REDIRECTED;
call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
}
neigh_release(n);
}
}
/* called in rcu_read_lock() section */
void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
static void ip_do_redirect(struct dst_entry *dst, struct sk_buff *skb)
{
const struct iphdr *iph = (const struct iphdr *) skb->data;
__be32 new_gw = icmp_hdr(skb)->un.gateway;
__be32 old_gw = ip_hdr(skb)->saddr;
struct net_device *dev = skb->dev;
__be32 daddr = iph->daddr;
__be32 saddr = iph->saddr;
struct net_device *dev = skb->dev;
struct in_device *in_dev = __in_dev_get_rcu(dev);
int ikeys[2] = { dev->ifindex, 0 };
__be32 skeys[2] = { saddr, 0 };
struct in_device *in_dev;
struct neighbour *n;
struct rtable *rt;
struct net *net;
int s, i;
if (!in_dev)
return;
switch (icmp_hdr(skb)->code & 7) {
case ICMP_REDIR_NET:
@ -1319,6 +1297,14 @@ void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
return;
}
rt = (struct rtable *) dst;
if (rt->rt_gateway != old_gw)
return;
in_dev = __in_dev_get_rcu(dev);
if (!in_dev)
return;
net = dev_net(dev);
if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
@ -1335,6 +1321,43 @@ void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
goto reject_redirect;
}
n = ipv4_neigh_lookup(dst, NULL, &new_gw);
if (n) {
if (!(n->nud_state & NUD_VALID)) {
neigh_event_send(n, NULL);
} else {
rt->rt_gateway = new_gw;
rt->rt_flags |= RTCF_REDIRECTED;
call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
}
neigh_release(n);
}
return;
reject_redirect:
#ifdef CONFIG_IP_ROUTE_VERBOSE
if (IN_DEV_LOG_MARTIANS(in_dev))
net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
" Advised path = %pI4 -> %pI4\n",
&old_gw, dev->name, &new_gw,
&saddr, &daddr);
#endif
;
}
/* called in rcu_read_lock() section */
void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
{
const struct iphdr *iph = (const struct iphdr *) skb->data;
__be32 daddr = iph->daddr;
__be32 saddr = iph->saddr;
struct net_device *dev = skb->dev;
int ikeys[2] = { dev->ifindex, 0 };
__be32 skeys[2] = { saddr, 0 };
struct net *net;
int s, i;
net = dev_net(dev);
for (s = 0; s < 2; s++) {
for (i = 0; i < 2; i++) {
unsigned int hash;
@ -1358,21 +1381,12 @@ void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
rt->dst.dev != dev)
continue;
ip_do_redirect(rt, old_gw, new_gw);
ip_do_redirect(&rt->dst, skb);
}
}
}
return;
reject_redirect:
#ifdef CONFIG_IP_ROUTE_VERBOSE
if (IN_DEV_LOG_MARTIANS(in_dev))
net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
" Advised path = %pI4 -> %pI4\n",
&old_gw, dev->name, &new_gw,
&saddr, &daddr);
#endif
;
}
static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)