ipmr.c

Linux Kernel 2.6.9 for OMAP1710

			kfree_skb(skb);
			return -ENOBUFS;
		}

		/*
		 *	Fill in the new cache entry
		 */
		c->mfc_parent=-1;
		c->mfc_origin=skb->nh.iph->saddr;
		c->mfc_mcastgrp=skb->nh.iph->daddr;

		/*
		 *	Reflect first query at mrouted.
		 */
		if ((err = ipmr_cache_report(skb, vifi, IGMPMSG_NOCACHE))<0) {
			/* If the report failed throw the cache entry 
			   out - Brad Parker
			 */
			spin_unlock_bh(&mfc_unres_lock);

			kmem_cache_free(mrt_cachep, c);
			kfree_skb(skb);
			return err;
		}

		atomic_inc(&cache_resolve_queue_len);
		c->next = mfc_unres_queue;
		mfc_unres_queue = c;

		mod_timer(&ipmr_expire_timer, c->mfc_un.unres.expires);
	}

	/*
	 *	See if we can append the packet
	 */
	if (c->mfc_un.unres.unresolved.qlen>3) {
		kfree_skb(skb);
		err = -ENOBUFS;
	} else {
		skb_queue_tail(&c->mfc_un.unres.unresolved,skb);
		err = 0;
	}

	spin_unlock_bh(&mfc_unres_lock);
	return err;
}

/*
 *	MFC cache manipulation by user space mroute daemon
 */

static int ipmr_mfc_delete(struct mfcctl *mfc)
{
	int line;
	struct mfc_cache *c, **cp;

	line=MFC_HASH(mfc->mfcc_mcastgrp.s_addr, mfc->mfcc_origin.s_addr);

	for (cp=&mfc_cache_array[line]; (c=*cp) != NULL; cp = &c->next) {
		if (c->mfc_origin == mfc->mfcc_origin.s_addr &&
		    c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr) {
			write_lock_bh(&mrt_lock);
			*cp = c->next;
			write_unlock_bh(&mrt_lock);

			kmem_cache_free(mrt_cachep, c);
			return 0;
		}
	}
	return -ENOENT;
}

static int ipmr_mfc_add(struct mfcctl *mfc, int mrtsock)
{
	int line;
	struct mfc_cache *uc, *c, **cp;

	line=MFC_HASH(mfc->mfcc_mcastgrp.s_addr, mfc->mfcc_origin.s_addr);

	for (cp=&mfc_cache_array[line]; (c=*cp) != NULL; cp = &c->next) {
		if (c->mfc_origin == mfc->mfcc_origin.s_addr &&
		    c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr)
			break;
	}

	if (c != NULL) {
		write_lock_bh(&mrt_lock);
		c->mfc_parent = mfc->mfcc_parent;
		ipmr_update_threshoulds(c, mfc->mfcc_ttls);
		if (!mrtsock)
			c->mfc_flags |= MFC_STATIC;
		write_unlock_bh(&mrt_lock);
		return 0;
	}

	if(!MULTICAST(mfc->mfcc_mcastgrp.s_addr))
		return -EINVAL;

	c=ipmr_cache_alloc();
	if (c==NULL)
		return -ENOMEM;

	c->mfc_origin=mfc->mfcc_origin.s_addr;
	c->mfc_mcastgrp=mfc->mfcc_mcastgrp.s_addr;
	c->mfc_parent=mfc->mfcc_parent;
	ipmr_update_threshoulds(c, mfc->mfcc_ttls);
	if (!mrtsock)
		c->mfc_flags |= MFC_STATIC;

	write_lock_bh(&mrt_lock);
	c->next = mfc_cache_array[line];
	mfc_cache_array[line] = c;
	write_unlock_bh(&mrt_lock);

	/*
	 *	Check to see if we resolved a queued list. If so we
	 *	need to send on the frames and tidy up.
	 */
	spin_lock_bh(&mfc_unres_lock);
	for (cp = &mfc_unres_queue; (uc=*cp) != NULL;
	     cp = &uc->next) {
		if (uc->mfc_origin == c->mfc_origin &&
		    uc->mfc_mcastgrp == c->mfc_mcastgrp) {
			*cp = uc->next;
			if (atomic_dec_and_test(&cache_resolve_queue_len))
				del_timer(&ipmr_expire_timer);
			break;
		}
	}
	spin_unlock_bh(&mfc_unres_lock);

	if (uc) {
		ipmr_cache_resolve(uc, c);
		kmem_cache_free(mrt_cachep, uc);
	}
	return 0;
}

/*
 *	Close the multicast socket, and clear the vif tables etc
 */
 
static void mroute_clean_tables(struct sock *sk)
{
	int i;
		
	/*
	 *	Shut down all active vif entries
	 */
	for(i=0; i<maxvif; i++) {
		if (!(vif_table[i].flags&VIFF_STATIC))
			vif_delete(i);
	}

	/*
	 *	Wipe the cache
	 */
	for (i=0;i<MFC_LINES;i++) {
		struct mfc_cache *c, **cp;

		cp = &mfc_cache_array[i];
		while ((c = *cp) != NULL) {
			if (c->mfc_flags&MFC_STATIC) {
				cp = &c->next;
				continue;
			}
			write_lock_bh(&mrt_lock);
			*cp = c->next;
			write_unlock_bh(&mrt_lock);

			kmem_cache_free(mrt_cachep, c);
		}
	}

	if (atomic_read(&cache_resolve_queue_len) != 0) {
		struct mfc_cache *c;

		spin_lock_bh(&mfc_unres_lock);
		while (mfc_unres_queue != NULL) {
			c = mfc_unres_queue;
			mfc_unres_queue = c->next;
			spin_unlock_bh(&mfc_unres_lock);

			ipmr_destroy_unres(c);

			spin_lock_bh(&mfc_unres_lock);
		}
		spin_unlock_bh(&mfc_unres_lock);
	}
}

static void mrtsock_destruct(struct sock *sk)
{
	rtnl_lock();
	if (sk == mroute_socket) {
		ipv4_devconf.mc_forwarding--;

		write_lock_bh(&mrt_lock);
		mroute_socket=NULL;
		write_unlock_bh(&mrt_lock);

		mroute_clean_tables(sk);
	}
	rtnl_unlock();
}

/*
 *	Socket options and virtual interface manipulation. The whole
 *	virtual interface system is a complete heap, but unfortunately
 *	that's how BSD mrouted happens to think. Maybe one day with a proper
 *	MOSPF/PIM router set up we can clean this up.
 */
 
int ip_mroute_setsockopt(struct sock *sk,int optname,char __user *optval,int optlen)
{
	int ret;
	struct vifctl vif;
	struct mfcctl mfc;
	
	if(optname!=MRT_INIT)
	{
		if(sk!=mroute_socket && !capable(CAP_NET_ADMIN))
			return -EACCES;
	}

	switch(optname)
	{
		case MRT_INIT:
			if (sk->sk_type != SOCK_RAW ||
			    inet_sk(sk)->num != IPPROTO_IGMP)
				return -EOPNOTSUPP;
			if(optlen!=sizeof(int))
				return -ENOPROTOOPT;

			rtnl_lock();
			if (mroute_socket) {
				rtnl_unlock();
				return -EADDRINUSE;
			}

			ret = ip_ra_control(sk, 1, mrtsock_destruct);
			if (ret == 0) {
				write_lock_bh(&mrt_lock);
				mroute_socket=sk;
				write_unlock_bh(&mrt_lock);

				ipv4_devconf.mc_forwarding++;
			}
			rtnl_unlock();
			return ret;
		case MRT_DONE:
			if (sk!=mroute_socket)
				return -EACCES;
			return ip_ra_control(sk, 0, NULL);
		case MRT_ADD_VIF:
		case MRT_DEL_VIF:
			if(optlen!=sizeof(vif))
				return -EINVAL;
			if (copy_from_user(&vif,optval,sizeof(vif)))
				return -EFAULT; 
			if(vif.vifc_vifi >= MAXVIFS)
				return -ENFILE;
			rtnl_lock();
			if (optname==MRT_ADD_VIF) {
				ret = vif_add(&vif, sk==mroute_socket);
			} else {
				ret = vif_delete(vif.vifc_vifi);
			}
			rtnl_unlock();
			return ret;

		/*
		 *	Manipulate the forwarding caches. These live
		 *	in a sort of kernel/user symbiosis.
		 */
		case MRT_ADD_MFC:
		case MRT_DEL_MFC:
			if(optlen!=sizeof(mfc))
				return -EINVAL;
			if (copy_from_user(&mfc,optval, sizeof(mfc)))
				return -EFAULT;
			rtnl_lock();
			if (optname==MRT_DEL_MFC)
				ret = ipmr_mfc_delete(&mfc);
			else
				ret = ipmr_mfc_add(&mfc, sk==mroute_socket);
			rtnl_unlock();
			return ret;
		/*
		 *	Control PIM assert.
		 */
		case MRT_ASSERT:
		{
			int v;
			if(get_user(v,(int __user *)optval))
				return -EFAULT;
			mroute_do_assert=(v)?1:0;
			return 0;
		}
#ifdef CONFIG_IP_PIMSM
		case MRT_PIM:
		{
			int v, ret;
			if(get_user(v,(int __user *)optval))
				return -EFAULT;
			v = (v)?1:0;
			rtnl_lock();
			ret = 0;
			if (v != mroute_do_pim) {
				mroute_do_pim = v;
				mroute_do_assert = v;
#ifdef CONFIG_IP_PIMSM_V2
				if (mroute_do_pim)
					ret = inet_add_protocol(&pim_protocol,
								IPPROTO_PIM);
				else
					ret = inet_del_protocol(&pim_protocol,
								IPPROTO_PIM);
				if (ret < 0)
					ret = -EAGAIN;
#endif
			}
			rtnl_unlock();
			return ret;
		}
#endif
		/*
		 *	Spurious command, or MRT_VERSION which you cannot
		 *	set.
		 */
		default:
			return -ENOPROTOOPT;
	}
}

/*
 *	Getsock opt support for the multicast routing system.
 */
 
int ip_mroute_getsockopt(struct sock *sk,int optname,char __user *optval,int __user *optlen)
{
	int olr;
	int val;

	if(optname!=MRT_VERSION && 
#ifdef CONFIG_IP_PIMSM
	   optname!=MRT_PIM &&
#endif
	   optname!=MRT_ASSERT)
		return -ENOPROTOOPT;

	if (get_user(olr, optlen))
		return -EFAULT;

	olr = min_t(unsigned int, olr, sizeof(int));
	if (olr < 0)
		return -EINVAL;
		
	if(put_user(olr,optlen))
		return -EFAULT;
	if(optname==MRT_VERSION)
		val=0x0305;
#ifdef CONFIG_IP_PIMSM
	else if(optname==MRT_PIM)
		val=mroute_do_pim;
#endif
	else
		val=mroute_do_assert;
	if(copy_to_user(optval,&val,olr))
		return -EFAULT;
	return 0;
}

/*
 *	The IP multicast ioctl support routines.
 */
 
int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
{
	struct sioc_sg_req sr;
	struct sioc_vif_req vr;
	struct vif_device *vif;
	struct mfc_cache *c;
	
	switch(cmd)
	{
		case SIOCGETVIFCNT:
			if (copy_from_user(&vr,arg,sizeof(vr)))
				return -EFAULT; 
			if(vr.vifi>=maxvif)
				return -EINVAL;
			read_lock(&mrt_lock);
			vif=&vif_table[vr.vifi];
			if(VIF_EXISTS(vr.vifi))	{
				vr.icount=vif->pkt_in;
				vr.ocount=vif->pkt_out;
				vr.ibytes=vif->bytes_in;
				vr.obytes=vif->bytes_out;
				read_unlock(&mrt_lock);

				if (copy_to_user(arg,&vr,sizeof(vr)))
					return -EFAULT;
				return 0;
			}
			read_unlock(&mrt_lock);
			return -EADDRNOTAVAIL;
		case SIOCGETSGCNT:
			if (copy_from_user(&sr,arg,sizeof(sr)))
				return -EFAULT;

			read_lock(&mrt_lock);
			c = ipmr_cache_find(sr.src.s_addr, sr.grp.s_addr);
			if (c) {
				sr.pktcnt = c->mfc_un.res.pkt;
				sr.bytecnt = c->mfc_un.res.bytes;
				sr.wrong_if = c->mfc_un.res.wrong_if;
				read_unlock(&mrt_lock);

				if (copy_to_user(arg,&sr,sizeof(sr)))
					return -EFAULT;
				return 0;
			}
			read_unlock(&mrt_lock);
			return -EADDRNOTAVAIL;
		default:
			return -ENOIOCTLCMD;
	}
}


static int ipmr_device_event(struct notifier_block *this, unsigned long event, void *ptr)
{
	struct vif_device *v;
	int ct;
	if (event != NETDEV_UNREGISTER)
		return NOTIFY_DONE;
	v=&vif_table[0];
	for(ct=0;ct<maxvif;ct++,v++) {
		if (v->dev==ptr)
			vif_delete(ct);
	}
	return NOTIFY_DONE;
}


static struct notifier_block ip_mr_notifier={
	.notifier_call = ipmr_device_event,
};

/*
 * 	Encapsulate a packet by attaching a valid IPIP header to it.
 *	This avoids tunnel drivers and other mess and gives us the speed so
 *	important for multicast video.
 */
 
static void ip_encap(struct sk_buff *skb, u32 saddr, u32 daddr)
{
	struct iphdr *iph = (struct iphdr *)skb_push(skb,sizeof(struct iphdr));

	iph->version	= 	4;
	iph->tos	=	skb->nh.iph->tos;
	iph->ttl	=	skb->nh.iph->ttl;
	iph->frag_off	=	0;
	iph->daddr	=	daddr;
	iph->saddr	=	saddr;
	iph->protocol	=	IPPROTO_IPIP;
	iph->ihl	=	5;
	iph->tot_len	=	htons(skb->len);
	ip_select_ident(iph, skb->dst, NULL);
	ip_send_check(iph);

	skb->h.ipiph = skb->nh.iph;
	skb->nh.iph = iph;
	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
	nf_reset(skb);
}

static inline int ipmr_forward_finish(struct sk_buff *skb)
{
	struct ip_options * opt	= &(IPCB(skb)->opt);

	IP_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS);

	if (unlikely(opt->optlen))
		ip_forward_options(skb);

	return dst_output(skb);
}

/*
 *	Processing handlers for ipmr_forward
 */

static void ipmr_queue_xmit(struct sk_buff *skb, struct mfc_cache *c, int vifi)
{
	struct iphdr *iph = skb->nh.iph;
	struct vif_device *vif = &vif_table[vifi];
	struct net_device *dev;
	struct rtable *rt;
	int    encap = 0;

	if (vif->dev == NULL)
		goto out_free;

#ifdef CONFIG_IP_PIMSM
	if (vif->flags & VIFF_REGISTER) {
		vif->pkt_out++;
		vif->bytes_out+=skb->len;
		((struct net_device_stats*)vif->dev->priv)->tx_bytes += skb->len;
		((struct net_device_stats*)vif->dev->priv)->tx_packets++;
		ipmr_cache_report(skb, vifi, IGMPMSG_WHOLEPKT);
		kfree_skb(skb);
		return;
	}
#endif

	if (vif->flags&VIFF_TUNNEL) {
		struct flowi fl = { .oif = vif->link,
				    .nl_u = { .ip4_u =
					      { .daddr = vif->remote,
						.saddr = vif->local,
						.tos = RT_TOS(iph->tos) } },
				    .proto = IPPROTO_IPIP };
		if (ip_route_output_key(&rt, &fl))
			goto out_free;
		encap = sizeof(struct iphdr);
	} else {
		struct flowi fl = { .oif = vif->link,
				    .nl_u = { .ip4_u =
					      { .daddr = iph->daddr,
						.tos = RT_TOS(iph->tos) } },
				    .proto = IPPROTO_IPIP };
		if (ip_route_output_key(&rt, &fl))
			goto out_free;
	}

	dev = rt->u.dst.dev;

	if (skb->len+encap > dst_pmtu(&rt->u.dst) && (ntohs(iph->frag_off) & IP_DF)) {
		/* Do not fragment multicasts. Alas, IPv4 does not
		   allow to send ICMP, so that packets will disappear
		   to blackhole.
		 */

		IP_INC_STATS_BH(IPSTATS_MIB_FRAGFAILS);
		ip_rt_put(rt);
		goto out_free;
	}

	encap += LL_RESERVED_SPACE(dev) + rt->u.dst.header_len;

	if (skb_cow(skb, encap)) {
 		ip_rt_put(rt);
		goto out_free;
	}

	vif->pkt_out++;
	vif->bytes_out+=skb->len;

	dst_release(skb->dst);
	skb->dst = &rt->u.dst;
	iph = skb->nh.iph;
	ip_decrease_ttl(iph);

	/* FIXME: forward and output firewalls used to be called here.
	 * What do we do with netfilter? -- RR */
	if (vif->flags & VIFF_TUNNEL) {
		ip_encap(skb, vif->local, vif->remote);
		/* FIXME: extra output firewall step used to be here. --RR */
		((struct ip_tunnel *)vif->dev->priv)->stat.tx_packets++;
		((struct ip_tunnel *)vif->dev->priv)->stat.tx_bytes+=skb->len;
	}

	IPCB(skb)->flags |= IPSKB_FORWARDED;

	/*
	 * RFC1584 teaches, that DVMRP/PIM router must deliver packets locally
	 * not only before forwarding, but after forwarding on all output
	 * interfaces. It is clear, if mrouter runs a multicasting
	 * program, it should receive packets not depending to what interface
	 * program is joined.
	 * If we will not make it, the program will have to join on all
	 * interfaces. On the other hand, multihoming host (or router, but
	 * not mrouter) cannot join to more than one interface - it will
	 * result in receiving multiple packets.
	 */
	NF_HOOK(PF_INET, NF_IP_FORWARD, skb, skb->dev, dev, 
		ipmr_forward_finish);
	return;

out_free:
	kfree_skb(skb);
	return;
}

static int ipmr_find_vif(struct net_device *dev)
{
	int ct;
	for (ct=maxvif-1; ct>=0; ct--) {
		if (vif_table[ct].dev == dev)
			break;
	}
	return ct;
}

/* "local" means that we should preserve one skb (for local delivery) */

static int ip_mr_forward(struct sk_buff *skb, struct mfc_cache *cache, int local)
{
	int psend = -1;
	int vif, ct;

	vif = cache->mfc_parent;
	cache->mfc_un.res.pkt++;
	cache->mfc_un.res.bytes += skb->len;

	/*
	 * Wrong interface: drop packet and (maybe) send PIM assert.
	 */
	if (vif_table[vif].dev != skb->dev) {
		int true_vifi;

		if (((struct rtable*)skb->dst)->fl.iif == 0) {
			/* It is our own packet, looped back.
			   Very complicated situation...

			   The best workaround until routing daemons will be
			   fixed is not to redistribute packet, if it was
			   send through wrong interface. It means, that
			   multicast applications WILL NOT work for
			   (S,G), which have default multicast route pointing
			   to wrong oif. In any case, it is not a good
			   idea to use multicasting applications on router.