[IPV6] MROUTE: Support PIM-SM (SSM).

Based on ancient patch by Mickael Hoerdt
<hoerdt@clarinet.u-strasbg.fr>, which is available at
<http://www-r2.u-strasbg.fr/~hoerdt/dev/linux_ipv6_mforwarding/patch-linux-ipv6-mforwarding-0.1a>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

2 files changed, 281 insertions, 1 deletions

diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index 9a2ea81e499f..82f987b4ef84 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -216,3 +216,10 @@ config IPV6_MROUTE
           Experimental support for IPv6 multicast forwarding.
           If unsure, say N.
 
+config IPV6_PIMSM_V2
+        bool "IPv6: PIM-SM version 2 support (EXPERIMENTAL)"
+        depends on IPV6_MROUTE
+        ---help---
+          Support for IPv6 PIM multicast routing protocol PIM-SMv2.
+          If unsure, say N.
+
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 1bdf3c177d58..2b70774be61f 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -54,6 +54,7 @@
 #include <net/ipv6.h>
 #include <net/ip6_route.h>
 #include <linux/mroute6.h>
+#include <linux/pim.h>
 #include <net/addrconf.h>
 #include <linux/netfilter_ipv6.h>
 
@@ -75,6 +76,13 @@ static int maxvif;
 
 #define MIF_EXISTS(idx) (vif6_table[idx].dev != NULL)
 
+static int mroute_do_assert;                            /* Set in PIM assert    */
+#ifdef CONFIG_IPV6_PIMSM_V2
+static int mroute_do_pim;
+#else
+#define mroute_do_pim 0
+#endif
+
 static struct mfc6_cache *mfc6_cache_array[MFC_LINES];  /* Forwarding cache     */
 
 static struct mfc6_cache *mfc_unres_queue;              /* Queue of unresolved entries */
@@ -97,6 +105,10 @@ static int ip6_mr_forward(struct sk_buff *skb, struct mfc6_cache *cache);
 static int ip6mr_cache_report(struct sk_buff *pkt, vifi_t vifi, int assert);
 static int ip6mr_fill_mroute(struct sk_buff *skb, struct mfc6_cache *c, struct rtmsg *rtm);
 
+#ifdef CONFIG_IPV6_PIMSM_V2
+static struct inet6_protocol pim6_protocol;
+#endif
+
 static struct timer_list ipmr_expire_timer;
 
 
@@ -339,6 +351,132 @@ static struct file_operations ip6mr_mfc_fops = {
 };
 #endif
 
+#ifdef CONFIG_IPV6_PIMSM_V2
+static int reg_vif_num = -1;
+
+static int pim6_rcv(struct sk_buff *skb)
+{
+        struct pimreghdr *pim;
+        struct ipv6hdr   *encap;
+        struct net_device  *reg_dev = NULL;
+
+        if (!pskb_may_pull(skb, sizeof(*pim) + sizeof(*encap)))
+                goto drop;
+
+        pim = (struct pimreghdr *)skb_transport_header(skb);
+        if (pim->type != ((PIM_VERSION << 4) | PIM_REGISTER) ||
+            (pim->flags & PIM_NULL_REGISTER) ||
+            (ip_compute_csum((void *)pim, sizeof(*pim)) != 0 &&
+             (u16)csum_fold(skb_checksum(skb, 0, skb->len, 0))))
+                goto drop;
+
+        /* check if the inner packet is destined to mcast group */
+        encap = (struct ipv6hdr *)(skb_transport_header(skb) +
+                                   sizeof(*pim));
+
+        if (!ipv6_addr_is_multicast(&encap->daddr) ||
+            encap->payload_len == 0 ||
+            ntohs(encap->payload_len) + sizeof(*pim) > skb->len)
+                goto drop;
+
+        read_lock(&mrt_lock);
+        if (reg_vif_num >= 0)
+                reg_dev = vif6_table[reg_vif_num].dev;
+        if (reg_dev)
+                dev_hold(reg_dev);
+        read_unlock(&mrt_lock);
+
+        if (reg_dev == NULL)
+                goto drop;
+
+        skb->mac_header = skb->network_header;
+        skb_pull(skb, (u8 *)encap - skb->data);
+        skb_reset_network_header(skb);
+        skb->dev = reg_dev;
+        skb->protocol = htons(ETH_P_IP);
+        skb->ip_summed = 0;
+        skb->pkt_type = PACKET_HOST;
+        dst_release(skb->dst);
+        ((struct net_device_stats *)netdev_priv(reg_dev))->rx_bytes += skb->len;
+        ((struct net_device_stats *)netdev_priv(reg_dev))->rx_packets++;
+        skb->dst = NULL;
+        nf_reset(skb);
+        netif_rx(skb);
+        dev_put(reg_dev);
+        return 0;
+ drop:
+        kfree_skb(skb);
+        return 0;
+}
+
+static struct inet6_protocol pim6_protocol = {
+        .handler        =       pim6_rcv,
+};
+
+/* Service routines creating virtual interfaces: PIMREG */
+
+static int reg_vif_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        read_lock(&mrt_lock);
+        ((struct net_device_stats *)netdev_priv(dev))->tx_bytes += skb->len;
+        ((struct net_device_stats *)netdev_priv(dev))->tx_packets++;
+        ip6mr_cache_report(skb, reg_vif_num, MRT6MSG_WHOLEPKT);
+        read_unlock(&mrt_lock);
+        kfree_skb(skb);
+        return 0;
+}
+
+static struct net_device_stats *reg_vif_get_stats(struct net_device *dev)
+{
+        return (struct net_device_stats *)netdev_priv(dev);
+}
+
+static void reg_vif_setup(struct net_device *dev)
+{
+        dev->type               = ARPHRD_PIMREG;
+        dev->mtu                = 1500 - sizeof(struct ipv6hdr) - 8;
+        dev->flags              = IFF_NOARP;
+        dev->hard_start_xmit    = reg_vif_xmit;
+        dev->get_stats          = reg_vif_get_stats;
+        dev->destructor         = free_netdev;
+}
+
+static struct net_device *ip6mr_reg_vif(void)
+{
+        struct net_device *dev;
+        struct inet6_dev *in_dev;
+
+        dev = alloc_netdev(sizeof(struct net_device_stats), "pim6reg",
+                           reg_vif_setup);
+
+        if (dev == NULL)
+                return NULL;
+
+        if (register_netdevice(dev)) {
+                free_netdev(dev);
+                return NULL;
+        }
+        dev->iflink = 0;
+
+        in_dev = ipv6_find_idev(dev);
+        if (!in_dev)
+                goto failure;
+
+        if (dev_open(dev))
+                goto failure;
+
+        return dev;
+
+failure:
+        /* allow the register to be completed before unregistering. */
+        rtnl_unlock();
+        rtnl_lock();
+
+        unregister_netdevice(dev);
+        return NULL;
+}
+#endif
+
 /*
  *      Delete a VIF entry
  */
@@ -361,6 +499,11 @@ static int mif6_delete(int vifi)
                 return -EADDRNOTAVAIL;
         }
 
+#ifdef CONFIG_IPV6_PIMSM_V2
+        if (vifi == reg_vif_num)
+                reg_vif_num = -1;
+#endif
+
         if (vifi + 1 == maxvif) {
                 int tmp;
                 for (tmp = vifi - 1; tmp >= 0; tmp--) {
@@ -480,6 +623,19 @@ static int mif6_add(struct mif6ctl *vifc, int mrtsock)
                 return -EADDRINUSE;
 
         switch (vifc->mif6c_flags) {
+#ifdef CONFIG_IPV6_PIMSM_V2
+        case MIFF_REGISTER:
+                /*
+                 * Special Purpose VIF in PIM
+                 * All the packets will be sent to the daemon
+                 */
+                if (reg_vif_num >= 0)
+                        return -EADDRINUSE;
+                dev = ip6mr_reg_vif();
+                if (!dev)
+                        return -ENOBUFS;
+                break;
+#endif
         case 0:
                 dev = dev_get_by_index(&init_net, vifc->mif6c_pifi);
                 if (!dev)
@@ -512,6 +668,10 @@ static int mif6_add(struct mif6ctl *vifc, int mrtsock)
         write_lock_bh(&mrt_lock);
         dev_hold(dev);
         v->dev = dev;
+#ifdef CONFIG_IPV6_PIMSM_V2
+        if (v->flags & MIFF_REGISTER)
+                reg_vif_num = vifi;
+#endif
         if (vifi + 1 > maxvif)
                 maxvif = vifi + 1;
         write_unlock_bh(&mrt_lock);
@@ -599,7 +759,13 @@ static int ip6mr_cache_report(struct sk_buff *pkt, vifi_t vifi, int assert)
         struct mrt6msg *msg;
         int ret;
 
-        skb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(*msg), GFP_ATOMIC);
+#ifdef CONFIG_IPV6_PIMSM_V2
+        if (assert == MRT6MSG_WHOLEPKT)
+                skb = skb_realloc_headroom(pkt, -skb_network_offset(pkt)
+                                                +sizeof(*msg));
+        else
+#endif
+                skb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(*msg), GFP_ATOMIC);
 
         if (!skb)
                 return -ENOBUFS;
@@ -609,6 +775,29 @@ static int ip6mr_cache_report(struct sk_buff *pkt, vifi_t vifi, int assert)
 
         skb->ip_summed = CHECKSUM_UNNECESSARY;
 
+#ifdef CONFIG_IPV6_PIMSM_V2
+        if (assert == MRT6MSG_WHOLEPKT) {
+                /* Ugly, but we have no choice with this interface.
+                   Duplicate old header, fix length etc.
+                   And all this only to mangle msg->im6_msgtype and
+                   to set msg->im6_mbz to "mbz" :-)
+                 */
+                skb_push(skb, -skb_network_offset(pkt));
+
+                skb_push(skb, sizeof(*msg));
+                skb_reset_transport_header(skb);
+                msg = (struct mrt6msg *)skb_transport_header(skb);
+                msg->im6_mbz = 0;
+                msg->im6_msgtype = MRT6MSG_WHOLEPKT;
+                msg->im6_mif = reg_vif_num;
+                msg->im6_pad = 0;
+                ipv6_addr_copy(&msg->im6_src, &ipv6_hdr(pkt)->saddr);
+                ipv6_addr_copy(&msg->im6_dst, &ipv6_hdr(pkt)->daddr);
+
+                skb->ip_summed = CHECKSUM_UNNECESSARY;
+        } else
+#endif
+        {
         /*
          *      Copy the IP header
          */
@@ -635,6 +824,7 @@ static int ip6mr_cache_report(struct sk_buff *pkt, vifi_t vifi, int assert)
         skb->ip_summed = CHECKSUM_UNNECESSARY;
 
         skb_pull(skb, sizeof(struct ipv6hdr));
+        }
 
         if (mroute6_socket == NULL) {
                 kfree_skb(skb);
@@ -1034,6 +1224,44 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, int
                 return ret;
 
         /*
+         *      Control PIM assert (to activate pim will activate assert)
+         */
+        case MRT6_ASSERT:
+        {
+                int v;
+                if (get_user(v, (int __user *)optval))
+                        return -EFAULT;
+                mroute_do_assert = !!v;
+                return 0;
+        }
+
+#ifdef CONFIG_IPV6_PIMSM_V2
+        case MRT6_PIM:
+        {
+                int v, ret;
+                if (get_user(v, (int __user *)optval))
+                        return -EFAULT;
+                v = !!v;
+                rtnl_lock();
+                ret = 0;
+                if (v != mroute_do_pim) {
+                        mroute_do_pim = v;
+                        mroute_do_assert = v;
+                        if (mroute_do_pim)
+                                ret = inet6_add_protocol(&pim6_protocol,
+                                                         IPPROTO_PIM);
+                        else
+                                ret = inet6_del_protocol(&pim6_protocol,
+                                                         IPPROTO_PIM);
+                        if (ret < 0)
+                                ret = -EAGAIN;
+                }
+                rtnl_unlock();
+                return ret;
+        }
+
+#endif
+        /*
          *      Spurious command, or MRT_VERSION which you cannot
          *      set.
          */
@@ -1056,6 +1284,14 @@ int ip6_mroute_getsockopt(struct sock *sk, int optname, char __user *optval,
         case MRT6_VERSION:
                 val = 0x0305;
                 break;
+#ifdef CONFIG_IPV6_PIMSM_V2
+        case MRT6_PIM:
+                val = mroute_do_pim;
+                break;
+#endif
+        case MRT6_ASSERT:
+                val = mroute_do_assert;
+                break;
         default:
                 return -ENOPROTOOPT;
         }
@@ -1151,6 +1387,18 @@ static int ip6mr_forward2(struct sk_buff *skb, struct mfc6_cache *c, int vifi)
         if (vif->dev == NULL)
                 goto out_free;
 
+#ifdef CONFIG_IPV6_PIMSM_V2
+        if (vif->flags & MIFF_REGISTER) {
+                vif->pkt_out++;
+                vif->bytes_out += skb->len;
+                ((struct net_device_stats *)netdev_priv(vif->dev))->tx_bytes += skb->len;
+                ((struct net_device_stats *)netdev_priv(vif->dev))->tx_packets++;
+                ip6mr_cache_report(skb, vifi, MRT6MSG_WHOLEPKT);
+                kfree_skb(skb);
+                return 0;
+        }
+#endif
+
         ipv6h = ipv6_hdr(skb);
 
         fl = (struct flowi) {
@@ -1220,6 +1468,30 @@ static int ip6_mr_forward(struct sk_buff *skb, struct mfc6_cache *cache)
         cache->mfc_un.res.pkt++;
         cache->mfc_un.res.bytes += skb->len;
 
+        /*
+         * Wrong interface: drop packet and (maybe) send PIM assert.
+         */
+        if (vif6_table[vif].dev != skb->dev) {
+                int true_vifi;
+
+                cache->mfc_un.res.wrong_if++;
+                true_vifi = ip6mr_find_vif(skb->dev);
+
+                if (true_vifi >= 0 && mroute_do_assert &&
+                    /* pimsm uses asserts, when switching from RPT to SPT,
+                       so that we cannot check that packet arrived on an oif.
+                       It is bad, but otherwise we would need to move pretty
+                       large chunk of pimd to kernel. Ough... --ANK
+                     */
+                    (mroute_do_pim || cache->mfc_un.res.ttls[true_vifi] < 255) &&
+                    time_after(jiffies,
+                               cache->mfc_un.res.last_assert + MFC_ASSERT_THRESH)) {
+                        cache->mfc_un.res.last_assert = jiffies;
+                        ip6mr_cache_report(skb, true_vifi, MRT6MSG_WRONGMIF);
+                }
+                goto dont_forward;
+        }
+
         vif6_table[vif].pkt_in++;
         vif6_table[vif].bytes_in += skb->len;
 
@@ -1241,6 +1513,7 @@ static int ip6_mr_forward(struct sk_buff *skb, struct mfc6_cache *cache)
                 return 0;
         }
 
+dont_forward:
         kfree_skb(skb);
         return 0;
 }