mcast.c

linux 内核源代码

			return NULL;
		psrc = (struct in6_addr *)skb_put(skb, sizeof(*psrc));
		*psrc = psf->sf_addr;
		scount++; stotal++;
		if ((type == MLD2_ALLOW_NEW_SOURCES ||
		     type == MLD2_BLOCK_OLD_SOURCES) && psf->sf_crcount) {
			psf->sf_crcount--;
			if ((sdeleted || gdeleted) && psf->sf_crcount == 0) {
				if (psf_prev)
					psf_prev->sf_next = psf->sf_next;
				else
					*psf_list = psf->sf_next;
				kfree(psf);
				continue;
			}
		}
		psf_prev = psf;
	}

empty_source:
	if (!stotal) {
		if (type == MLD2_ALLOW_NEW_SOURCES ||
		    type == MLD2_BLOCK_OLD_SOURCES)
			return skb;
		if (pmc->mca_crcount || isquery) {
			/* make sure we have room for group header */
			if (skb && AVAILABLE(skb) < sizeof(struct mld2_grec)) {
				mld_sendpack(skb);
				skb = NULL; /* add_grhead will get a new one */
			}
			skb = add_grhead(skb, pmc, type, &pgr);
		}
	}
	if (pgr)
		pgr->grec_nsrcs = htons(scount);

	if (isquery)
		pmc->mca_flags &= ~MAF_GSQUERY;	/* clear query state */
	return skb;
}

static void mld_send_report(struct inet6_dev *idev, struct ifmcaddr6 *pmc)
{
	struct sk_buff *skb = NULL;
	int type;

	if (!pmc) {
		read_lock_bh(&idev->lock);
		for (pmc=idev->mc_list; pmc; pmc=pmc->next) {
			if (pmc->mca_flags & MAF_NOREPORT)
				continue;
			spin_lock_bh(&pmc->mca_lock);
			if (pmc->mca_sfcount[MCAST_EXCLUDE])
				type = MLD2_MODE_IS_EXCLUDE;
			else
				type = MLD2_MODE_IS_INCLUDE;
			skb = add_grec(skb, pmc, type, 0, 0);
			spin_unlock_bh(&pmc->mca_lock);
		}
		read_unlock_bh(&idev->lock);
	} else {
		spin_lock_bh(&pmc->mca_lock);
		if (pmc->mca_sfcount[MCAST_EXCLUDE])
			type = MLD2_MODE_IS_EXCLUDE;
		else
			type = MLD2_MODE_IS_INCLUDE;
		skb = add_grec(skb, pmc, type, 0, 0);
		spin_unlock_bh(&pmc->mca_lock);
	}
	if (skb)
		mld_sendpack(skb);
}

/*
 * remove zero-count source records from a source filter list
 */
static void mld_clear_zeros(struct ip6_sf_list **ppsf)
{
	struct ip6_sf_list *psf_prev, *psf_next, *psf;

	psf_prev = NULL;
	for (psf=*ppsf; psf; psf = psf_next) {
		psf_next = psf->sf_next;
		if (psf->sf_crcount == 0) {
			if (psf_prev)
				psf_prev->sf_next = psf->sf_next;
			else
				*ppsf = psf->sf_next;
			kfree(psf);
		} else
			psf_prev = psf;
	}
}

static void mld_send_cr(struct inet6_dev *idev)
{
	struct ifmcaddr6 *pmc, *pmc_prev, *pmc_next;
	struct sk_buff *skb = NULL;
	int type, dtype;

	read_lock_bh(&idev->lock);
	write_lock_bh(&idev->mc_lock);

	/* deleted MCA's */
	pmc_prev = NULL;
	for (pmc=idev->mc_tomb; pmc; pmc=pmc_next) {
		pmc_next = pmc->next;
		if (pmc->mca_sfmode == MCAST_INCLUDE) {
			type = MLD2_BLOCK_OLD_SOURCES;
			dtype = MLD2_BLOCK_OLD_SOURCES;
			skb = add_grec(skb, pmc, type, 1, 0);
			skb = add_grec(skb, pmc, dtype, 1, 1);
		}
		if (pmc->mca_crcount) {
			if (pmc->mca_sfmode == MCAST_EXCLUDE) {
				type = MLD2_CHANGE_TO_INCLUDE;
				skb = add_grec(skb, pmc, type, 1, 0);
			}
			pmc->mca_crcount--;
			if (pmc->mca_crcount == 0) {
				mld_clear_zeros(&pmc->mca_tomb);
				mld_clear_zeros(&pmc->mca_sources);
			}
		}
		if (pmc->mca_crcount == 0 && !pmc->mca_tomb &&
		    !pmc->mca_sources) {
			if (pmc_prev)
				pmc_prev->next = pmc_next;
			else
				idev->mc_tomb = pmc_next;
			in6_dev_put(pmc->idev);
			kfree(pmc);
		} else
			pmc_prev = pmc;
	}
	write_unlock_bh(&idev->mc_lock);

	/* change recs */
	for (pmc=idev->mc_list; pmc; pmc=pmc->next) {
		spin_lock_bh(&pmc->mca_lock);
		if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
			type = MLD2_BLOCK_OLD_SOURCES;
			dtype = MLD2_ALLOW_NEW_SOURCES;
		} else {
			type = MLD2_ALLOW_NEW_SOURCES;
			dtype = MLD2_BLOCK_OLD_SOURCES;
		}
		skb = add_grec(skb, pmc, type, 0, 0);
		skb = add_grec(skb, pmc, dtype, 0, 1);	/* deleted sources */

		/* filter mode changes */
		if (pmc->mca_crcount) {
			if (pmc->mca_sfmode == MCAST_EXCLUDE)
				type = MLD2_CHANGE_TO_EXCLUDE;
			else
				type = MLD2_CHANGE_TO_INCLUDE;
			skb = add_grec(skb, pmc, type, 0, 0);
			pmc->mca_crcount--;
		}
		spin_unlock_bh(&pmc->mca_lock);
	}
	read_unlock_bh(&idev->lock);
	if (!skb)
		return;
	(void) mld_sendpack(skb);
}

static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
{
	struct sock *sk = igmp6_socket->sk;
	struct inet6_dev *idev;
	struct sk_buff *skb;
	struct icmp6hdr *hdr;
	struct in6_addr *snd_addr;
	struct in6_addr *addrp;
	struct in6_addr addr_buf;
	struct in6_addr all_routers;
	int err, len, payload_len, full_len;
	u8 ra[8] = { IPPROTO_ICMPV6, 0,
		     IPV6_TLV_ROUTERALERT, 2, 0, 0,
		     IPV6_TLV_PADN, 0 };

	rcu_read_lock();
	IP6_INC_STATS(__in6_dev_get(dev),
		      IPSTATS_MIB_OUTREQUESTS);
	rcu_read_unlock();
	snd_addr = addr;
	if (type == ICMPV6_MGM_REDUCTION) {
		snd_addr = &all_routers;
		ipv6_addr_all_routers(&all_routers);
	}

	len = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
	payload_len = len + sizeof(ra);
	full_len = sizeof(struct ipv6hdr) + payload_len;

	skb = sock_alloc_send_skb(sk, LL_RESERVED_SPACE(dev) + full_len, 1, &err);

	if (skb == NULL) {
		rcu_read_lock();
		IP6_INC_STATS(__in6_dev_get(dev),
			      IPSTATS_MIB_OUTDISCARDS);
		rcu_read_unlock();
		return;
	}

	skb_reserve(skb, LL_RESERVED_SPACE(dev));

	if (ipv6_get_lladdr(dev, &addr_buf, IFA_F_TENTATIVE)) {
		/* <draft-ietf-magma-mld-source-05.txt>:
		 * use unspecified address as the source address
		 * when a valid link-local address is not available.
		 */
		memset(&addr_buf, 0, sizeof(addr_buf));
	}

	ip6_nd_hdr(sk, skb, dev, &addr_buf, snd_addr, NEXTHDR_HOP, payload_len);

	memcpy(skb_put(skb, sizeof(ra)), ra, sizeof(ra));

	hdr = (struct icmp6hdr *) skb_put(skb, sizeof(struct icmp6hdr));
	memset(hdr, 0, sizeof(struct icmp6hdr));
	hdr->icmp6_type = type;

	addrp = (struct in6_addr *) skb_put(skb, sizeof(struct in6_addr));
	ipv6_addr_copy(addrp, addr);

	hdr->icmp6_cksum = csum_ipv6_magic(&addr_buf, snd_addr, len,
					   IPPROTO_ICMPV6,
					   csum_partial((__u8 *) hdr, len, 0));

	idev = in6_dev_get(skb->dev);

	err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dev,
		mld_dev_queue_xmit);
	if (!err) {
		ICMP6MSGOUT_INC_STATS(idev, type);
		ICMP6_INC_STATS(idev, ICMP6_MIB_OUTMSGS);
		IP6_INC_STATS(idev, IPSTATS_MIB_OUTMCASTPKTS);
	} else
		IP6_INC_STATS(idev, IPSTATS_MIB_OUTDISCARDS);

	if (likely(idev != NULL))
		in6_dev_put(idev);
	return;
}

static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
	struct in6_addr *psfsrc)
{
	struct ip6_sf_list *psf, *psf_prev;
	int rv = 0;

	psf_prev = NULL;
	for (psf=pmc->mca_sources; psf; psf=psf->sf_next) {
		if (ipv6_addr_equal(&psf->sf_addr, psfsrc))
			break;
		psf_prev = psf;
	}
	if (!psf || psf->sf_count[sfmode] == 0) {
		/* source filter not found, or count wrong =>  bug */
		return -ESRCH;
	}
	psf->sf_count[sfmode]--;
	if (!psf->sf_count[MCAST_INCLUDE] && !psf->sf_count[MCAST_EXCLUDE]) {
		struct inet6_dev *idev = pmc->idev;

		/* no more filters for this source */
		if (psf_prev)
			psf_prev->sf_next = psf->sf_next;
		else
			pmc->mca_sources = psf->sf_next;
		if (psf->sf_oldin && !(pmc->mca_flags & MAF_NOREPORT) &&
		    !MLD_V1_SEEN(idev)) {
			psf->sf_crcount = idev->mc_qrv;
			psf->sf_next = pmc->mca_tomb;
			pmc->mca_tomb = psf;
			rv = 1;
		} else
			kfree(psf);
	}
	return rv;
}

static int ip6_mc_del_src(struct inet6_dev *idev, struct in6_addr *pmca,
			  int sfmode, int sfcount, struct in6_addr *psfsrc,
			  int delta)
{
	struct ifmcaddr6 *pmc;
	int	changerec = 0;
	int	i, err;

	if (!idev)
		return -ENODEV;
	read_lock_bh(&idev->lock);
	for (pmc=idev->mc_list; pmc; pmc=pmc->next) {
		if (ipv6_addr_equal(pmca, &pmc->mca_addr))
			break;
	}
	if (!pmc) {
		/* MCA not found?? bug */
		read_unlock_bh(&idev->lock);
		return -ESRCH;
	}
	spin_lock_bh(&pmc->mca_lock);
	sf_markstate(pmc);
	if (!delta) {
		if (!pmc->mca_sfcount[sfmode]) {
			spin_unlock_bh(&pmc->mca_lock);
			read_unlock_bh(&idev->lock);
			return -EINVAL;
		}
		pmc->mca_sfcount[sfmode]--;
	}
	err = 0;
	for (i=0; i<sfcount; i++) {
		int rv = ip6_mc_del1_src(pmc, sfmode, &psfsrc[i]);

		changerec |= rv > 0;
		if (!err && rv < 0)
			err = rv;
	}
	if (pmc->mca_sfmode == MCAST_EXCLUDE &&
	    pmc->mca_sfcount[MCAST_EXCLUDE] == 0 &&
	    pmc->mca_sfcount[MCAST_INCLUDE]) {
		struct ip6_sf_list *psf;

		/* filter mode change */
		pmc->mca_sfmode = MCAST_INCLUDE;
		pmc->mca_crcount = idev->mc_qrv;
		idev->mc_ifc_count = pmc->mca_crcount;
		for (psf=pmc->mca_sources; psf; psf = psf->sf_next)
			psf->sf_crcount = 0;
		mld_ifc_event(pmc->idev);
	} else if (sf_setstate(pmc) || changerec)
		mld_ifc_event(pmc->idev);
	spin_unlock_bh(&pmc->mca_lock);
	read_unlock_bh(&idev->lock);
	return err;
}

/*
 * Add multicast single-source filter to the interface list
 */
static int ip6_mc_add1_src(struct ifmcaddr6 *pmc, int sfmode,
	struct in6_addr *psfsrc, int delta)
{
	struct ip6_sf_list *psf, *psf_prev;

	psf_prev = NULL;
	for (psf=pmc->mca_sources; psf; psf=psf->sf_next) {
		if (ipv6_addr_equal(&psf->sf_addr, psfsrc))
			break;
		psf_prev = psf;
	}
	if (!psf) {
		psf = kzalloc(sizeof(*psf), GFP_ATOMIC);
		if (!psf)
			return -ENOBUFS;

		psf->sf_addr = *psfsrc;
		if (psf_prev) {
			psf_prev->sf_next = psf;
		} else
			pmc->mca_sources = psf;
	}
	psf->sf_count[sfmode]++;
	return 0;
}

static void sf_markstate(struct ifmcaddr6 *pmc)
{
	struct ip6_sf_list *psf;
	int mca_xcount = pmc->mca_sfcount[MCAST_EXCLUDE];

	for (psf=pmc->mca_sources; psf; psf=psf->sf_next)
		if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
			psf->sf_oldin = mca_xcount ==
				psf->sf_count[MCAST_EXCLUDE] &&
				!psf->sf_count[MCAST_INCLUDE];
		} else
			psf->sf_oldin = psf->sf_count[MCAST_INCLUDE] != 0;
}

static int sf_setstate(struct ifmcaddr6 *pmc)
{
	struct ip6_sf_list *psf, *dpsf;
	int mca_xcount = pmc->mca_sfcount[MCAST_EXCLUDE];
	int qrv = pmc->idev->mc_qrv;
	int new_in, rv;

	rv = 0;
	for (psf=pmc->mca_sources; psf; psf=psf->sf_next) {
		if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
			new_in = mca_xcount == psf->sf_count[MCAST_EXCLUDE] &&
				!psf->sf_count[MCAST_INCLUDE];
		} else
			new_in = psf->sf_count[MCAST_INCLUDE] != 0;
		if (new_in) {
			if (!psf->sf_oldin) {
				struct ip6_sf_list *prev = NULL;

				for (dpsf=pmc->mca_tomb; dpsf;
				     dpsf=dpsf->sf_next) {
					if (ipv6_addr_equal(&dpsf->sf_addr,
					    &psf->sf_addr))
						break;
					prev = dpsf;
				}
				if (dpsf) {
					if (prev)
						prev->sf_next = dpsf->sf_next;
					else
						pmc->mca_tomb = dpsf->sf_next;
					kfree(dpsf);
				}
				psf->sf_crcount = qrv;
				rv++;
			}
		} else if (psf->sf_oldin) {
			psf->sf_crcount = 0;
			/*
			 * add or update "delete" records if an active filter
			 * is now inactive
			 */
			for (dpsf=pmc->mca_tomb; dpsf; dpsf=dpsf->sf_next)
				if (ipv6_addr_equal(&dpsf->sf_addr,
				    &psf->sf_addr))
					break;
			if (!dpsf) {
				dpsf = (struct ip6_sf_list *)
					kmalloc(sizeof(*dpsf), GFP_ATOMIC);
				if (!dpsf)
					continue;
				*dpsf = *psf;
				/* pmc->mca_lock held by callers */
				dpsf->sf_next = pmc->mca_tomb;
				pmc->mca_tomb = dpsf;
			}
			dpsf->sf_crcount = qrv;
			rv++;
		}
	}
	return rv;
}

/*
 * Add multicast source filter list to the interface list
 */
static int ip6_mc_add_src(struct inet6_dev *idev, struct in6_addr *pmca,
			  int sfmode, int sfcount, struct in6_addr *psfsrc,
			  int delta)
{
	struct ifmcaddr6 *pmc;
	int	isexclude;
	int	i, err;

	if (!idev)
		return -ENODEV;
	read_lock_bh(&idev->lock);
	for (pmc=idev->mc_list; pmc; pmc=pmc->next) {
		if (ipv6_addr_equal(pmca, &pmc->mca_addr))
			break;
	}
	if (!pmc) {
		/* MCA not found?? bug */
		read_unlock_bh(&idev->lock);
		return -ESRCH;
	}
	spin_lock_bh(&pmc->mca_lock);

	sf_markstate(pmc);
	isexclude = pmc->mca_sfmode == MCAST_EXCLUDE;
	if (!delta)
		pmc->mca_sfcount[sfmode]++;
	err = 0;
	for (i=0; i<sfcount; i++) {
		err = ip6_mc_add1_src(pmc, sfmode, &psfsrc[i], delta);
		if (err)
			break;
	}
	if (err) {
		int j;

		if (!delta)
			pmc->mca_sfcount[sfmode]--;
		for (j=0; j<i; j++)
			(void) ip6_mc_del1_src(pmc, sfmode, &psfsrc[i]);
	} else if (isexclude != (pmc->mca_sfcount[MCAST_EXCLUDE] != 0)) {
		struct inet6_dev *idev = pmc->idev;
		struct ip6_sf_list *psf;

		/* filter mode change */
		if (pmc->mca_sfcount[MCAST_EXCLUDE])
			pmc->mca_sfmode = MCAST_EXCLUDE;
		else if (pmc->mca_sfcount[MCAST_INCLUDE])
			pmc->mca_sfmode = MCAST_INCLUDE;
		/* else no filters; keep old mode for reports */

		pmc->mca_crcount = idev->mc_qrv;
		idev->mc_ifc_count = pmc->mca_crcount;
		for (psf=pmc->mca_sources; psf; psf = psf->sf_next)
			psf->sf_crcount = 0;
		mld_ifc_event(idev);
	} else if (sf_setstate(pmc))
		mld_ifc_event(idev);
	spin_unlock_bh(&pmc->mca_lock);
	read_unlock_bh(&idev->lock);
	return err;
}

static void ip6_mc_clear_src(struct ifmcaddr6 *pmc)
{
	struct ip6_sf_list *psf, *nextpsf;

	for (psf=pmc->mca_tomb; psf; psf=nextpsf) {
		nextpsf = psf->sf_next;
		kfree(psf);
	}
	pmc->mca_tomb = NULL;
	for (psf=pmc->mca_sources; psf; psf=nextpsf) {
		nextpsf = psf->sf_next;
		kfree(psf);
	}
	pmc->mca_sources = NULL;
	pmc->mca_sfmode = MCAST_EXCLUDE;
	pmc->mca_sfcount[MCAST_INCLUDE] = 0;
	pmc->mca_sfcount[MCAST_EXCLUDE] = 1;