[IPV6] MIP6: Report to user-space when home address option is rejected.

Report to user-space when home address option is rejected.
In receiving this message user-space application will send Mobile IPv6 binding
error. It is rate-limited by kernel.
Based on MIPL2 kernel patch.

This patch was also written by: Ville Nuorvala <vnuorval@tcs.hut.fi>

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/mip6.c b/net/ipv6/mip6.c
index 7b5f89321482623d9e4e67f4725e49441bb98425..31445d09261e402272444f30d58b914da55b303b 100644 (file)
--- a/net/ipv6/mip6.c
+++ b/net/ipv6/mip6.c
@@ -25,6 +25,7 @@
 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/skbuff.h>
+#include <linux/time.h>
 #include <linux/ipv6.h>
 #include <linux/icmpv6.h>
 #include <net/sock.h>
@@ -138,6 +139,18 @@ int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
        return 0;
 }
 
+struct mip6_report_rate_limiter {
+       spinlock_t lock;
+       struct timeval stamp;
+       int iif;
+       struct in6_addr src;
+       struct in6_addr dst;
+};
+
+static struct mip6_report_rate_limiter mip6_report_rl = {
+       .lock = SPIN_LOCK_UNLOCKED
+};
+
 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
 {
        struct ipv6hdr *iph = skb->nh.ipv6h;
@@ -189,6 +202,75 @@ static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
        return 0;
 }
 
+static inline int mip6_report_rl_allow(struct timeval *stamp,
+                                      struct in6_addr *dst,
+                                      struct in6_addr *src, int iif)
+{
+       int allow = 0;
+
+       spin_lock_bh(&mip6_report_rl.lock);
+       if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
+           mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
+           mip6_report_rl.iif != iif ||
+           !ipv6_addr_equal(&mip6_report_rl.src, src) ||
+           !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
+               mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
+               mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
+               mip6_report_rl.iif = iif;
+               ipv6_addr_copy(&mip6_report_rl.src, src);
+               ipv6_addr_copy(&mip6_report_rl.dst, dst);
+               allow = 1;
+       }
+       spin_unlock_bh(&mip6_report_rl.lock);
+       return allow;
+}
+
+static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct flowi *fl)
+{
+       struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
+       struct ipv6_destopt_hao *hao = NULL;
+       struct xfrm_selector sel;
+       int offset;
+       struct timeval stamp;
+       int err = 0;
+
+       if (likely(opt->dsthao)) {
+               offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
+               if (likely(offset >= 0))
+                       hao = (struct ipv6_destopt_hao *)(skb->nh.raw + offset);
+       }
+
+       skb_get_timestamp(skb, &stamp);
+
+       if (!mip6_report_rl_allow(&stamp, &skb->nh.ipv6h->daddr,
+                                 hao ? &hao->addr : &skb->nh.ipv6h->saddr,
+                                 opt->iif))
+               goto out;
+
+       memset(&sel, 0, sizeof(sel));
+       memcpy(&sel.daddr, (xfrm_address_t *)&skb->nh.ipv6h->daddr,
+              sizeof(sel.daddr));
+       sel.prefixlen_d = 128;
+       memcpy(&sel.saddr, (xfrm_address_t *)&skb->nh.ipv6h->saddr,
+              sizeof(sel.saddr));
+       sel.prefixlen_s = 128;
+       sel.family = AF_INET6;
+       sel.proto = fl->proto;
+       sel.dport = xfrm_flowi_dport(fl);
+       if (sel.dport)
+               sel.dport_mask = ~((__u16)0);
+       sel.sport = xfrm_flowi_sport(fl);
+       if (sel.sport)
+               sel.sport_mask = ~((__u16)0);
+       sel.ifindex = fl->oif;
+
+       err = km_report(IPPROTO_DSTOPTS, &sel,
+                       (hao ? (xfrm_address_t *)&hao->addr : NULL));
+
+ out:
+       return err;
+}
+
 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
                               u8 **nexthdr)
 {
@@ -273,6 +355,7 @@ static struct xfrm_type mip6_destopt_type =
        .destructor     = mip6_destopt_destroy,
        .input          = mip6_destopt_input,
        .output         = mip6_destopt_output,
+       .reject         = mip6_destopt_reject,
        .hdr_offset     = mip6_destopt_offset,
        .local_addr     = mip6_xfrm_addr,
 };