[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>

1 files changed, 83 insertions, 0 deletions

diff --git a/net/ipv6/mip6.c b/net/ipv6/mip6.c
index 7b5f89321482..31445d09261e 100644
--- 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,
 };