mcast.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,496 行 · 第 1/4 页

static int
mld_scount(struct ifmcaddr6 *pmc, int type, int gdeleted, int sdeleted)
{
	struct ip6_sf_list *psf;
	int scount = 0;

	for (psf=pmc->mca_sources; psf; psf=psf->sf_next) {
		if (!is_in(pmc, psf, type, gdeleted, sdeleted))
			continue;
		scount++;
	}
	return scount;
}

static struct sk_buff *mld_newpack(struct net_device *dev, int size)
{
	struct sock *sk = igmp6_socket->sk;
	struct sk_buff *skb;
	struct mld2_report *pmr;
	struct in6_addr addr_buf;
	int err;
	u8 ra[8] = { IPPROTO_ICMPV6, 0,
		     IPV6_TLV_ROUTERALERT, 2, 0, 0,
		     IPV6_TLV_PADN, 0 };

	/* we assume size > sizeof(ra) here */
	skb = sock_alloc_send_skb(sk, size + LL_RESERVED_SPACE(dev), 1, &err);

	if (skb == 0)
		return NULL;

	skb_reserve(skb, LL_RESERVED_SPACE(dev));
	if (dev->hard_header) {
		unsigned char ha[MAX_ADDR_LEN];

		ndisc_mc_map(&mld2_all_mcr, ha, dev, 1);
		if (dev->hard_header(skb, dev, ETH_P_IPV6,ha,NULL,size) < 0) {
			kfree_skb(skb);
			return NULL;
		}
	}

	if (ipv6_get_lladdr(dev, &addr_buf)) {
		/* <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, &mld2_all_mcr, NEXTHDR_HOP, 0);

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

	pmr =(struct mld2_report *)skb_put(skb, sizeof(*pmr));
	skb->h.raw = (unsigned char *)pmr;
	pmr->type = ICMPV6_MLD2_REPORT;
	pmr->resv1 = 0;
	pmr->csum = 0;
	pmr->resv2 = 0;
	pmr->ngrec = 0;
	return skb;
}

static void mld_sendpack(struct sk_buff *skb)
{
	struct ipv6hdr *pip6 = skb->nh.ipv6h;
	struct mld2_report *pmr = (struct mld2_report *)skb->h.raw;
	int payload_len, mldlen;
	struct inet6_dev *idev = in6_dev_get(skb->dev);
	int err;

	IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
	payload_len = skb->tail - (unsigned char *)skb->nh.ipv6h -
		sizeof(struct ipv6hdr);
	mldlen = skb->tail - skb->h.raw;
	pip6->payload_len = htons(payload_len);

	pmr->csum = csum_ipv6_magic(&pip6->saddr, &pip6->daddr, mldlen,
		IPPROTO_ICMPV6, csum_partial(skb->h.raw, mldlen, 0));
	err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dev,
		dev_queue_xmit);
	if (!err) {
		ICMP6_INC_STATS(idev,ICMP6_MIB_OUTMSGS);
		IP6_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS);
	} else
		IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);

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

static int grec_size(struct ifmcaddr6 *pmc, int type, int gdel, int sdel)
{
	return sizeof(struct mld2_grec) + 4*mld_scount(pmc,type,gdel,sdel);
}

static struct sk_buff *add_grhead(struct sk_buff *skb, struct ifmcaddr6 *pmc,
	int type, struct mld2_grec **ppgr)
{
	struct net_device *dev = pmc->idev->dev;
	struct mld2_report *pmr;
	struct mld2_grec *pgr;

	if (!skb)
		skb = mld_newpack(dev, dev->mtu);
	if (!skb)
		return NULL;
	pgr = (struct mld2_grec *)skb_put(skb, sizeof(struct mld2_grec));
	pgr->grec_type = type;
	pgr->grec_auxwords = 0;
	pgr->grec_nsrcs = 0;
	pgr->grec_mca = pmc->mca_addr;	/* structure copy */
	pmr = (struct mld2_report *)skb->h.raw;
	pmr->ngrec = htons(ntohs(pmr->ngrec)+1);
	*ppgr = pgr;
	return skb;
}

#define AVAILABLE(skb) ((skb) ? ((skb)->dev ? (skb)->dev->mtu - (skb)->len : \
	skb_tailroom(skb)) : 0)

static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,
	int type, int gdeleted, int sdeleted)
{
	struct net_device *dev = pmc->idev->dev;
	struct mld2_report *pmr;
	struct mld2_grec *pgr = NULL;
	struct ip6_sf_list *psf, *psf_next, *psf_prev, **psf_list;
	int scount, first, isquery, truncate;

	if (pmc->mca_flags & MAF_NOREPORT)
		return skb;

	isquery = type == MLD2_MODE_IS_INCLUDE ||
		  type == MLD2_MODE_IS_EXCLUDE;
	truncate = type == MLD2_MODE_IS_EXCLUDE ||
		    type == MLD2_CHANGE_TO_EXCLUDE;

	psf_list = sdeleted ? &pmc->mca_tomb : &pmc->mca_sources;

	if (!*psf_list) {
		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 and at
			 * least one source.
			 */
			if (skb && AVAILABLE(skb) < sizeof(struct mld2_grec)+
			    sizeof(struct in6_addr)) {
				mld_sendpack(skb);
				skb = NULL; /* add_grhead will get a new one */
			}
			skb = add_grhead(skb, pmc, type, &pgr);
		}
		return skb;
	}
	pmr = skb ? (struct mld2_report *)skb->h.raw : NULL;

	/* EX and TO_EX get a fresh packet, if needed */
	if (truncate) {
		if (pmr && pmr->ngrec &&
		    AVAILABLE(skb) < grec_size(pmc, type, gdeleted, sdeleted)) {
			if (skb)
				mld_sendpack(skb);
			skb = mld_newpack(dev, dev->mtu);
		}
	}
	first = 1;
	scount = 0;
	psf_prev = NULL;
	for (psf=*psf_list; psf; psf=psf_next) {
		struct in6_addr *psrc;

		psf_next = psf->sf_next;

		if (!is_in(pmc, psf, type, gdeleted, sdeleted)) {
			psf_prev = psf;
			continue;
		}

		/* clear marks on query responses */
		if (isquery)
			psf->sf_gsresp = 0;

		if (AVAILABLE(skb) < sizeof(*psrc) +
		    first*sizeof(struct mld2_grec)) {
			if (truncate && !first)
				break;	 /* truncate these */
			if (pgr)
				pgr->grec_nsrcs = htons(scount);
			if (skb)
				mld_sendpack(skb);
			skb = mld_newpack(dev, dev->mtu);
			first = 1;
			scount = 0;
		}
		if (first) {
			skb = add_grhead(skb, pmc, type, &pgr);
			first = 0;
		}
		psrc = (struct in6_addr *)skb_put(skb, sizeof(*psrc));
		*psrc = psf->sf_addr;
		scount++;
		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;
	}
	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) {
			pmc->mca_crcount--;
			if (pmc->mca_sfmode == MCAST_EXCLUDE) {
				type = MLD2_CHANGE_TO_INCLUDE;
				skb = add_grec(skb, pmc, type, 1, 0);
			}
			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) {
			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);
		}
		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 };

	IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
	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) {
		IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
		return;
	}

	skb_reserve(skb, LL_RESERVED_SPACE(dev));
	if (dev->hard_header) {
		unsigned char ha[MAX_ADDR_LEN];
		ndisc_mc_map(snd_addr, ha, dev, 1);
		if (dev->hard_header(skb, dev, ETH_P_IPV6, ha, NULL, full_len) < 0)
			goto out;
	}

	if (ipv6_get_lladdr(dev, &addr_buf)) {
		/* <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,
		dev_queue_xmit);
	if (!err) {
		if (type == ICMPV6_MGM_REDUCTION)
			ICMP6_INC_STATS(idev, ICMP6_MIB_OUTGROUPMEMBREDUCTIONS);
		else
			ICMP6_INC_STATS(idev, ICMP6_MIB_OUTGROUPMEMBRESPONSES);
		ICMP6_INC_STATS(idev, ICMP6_MIB_OUTMSGS);
		IP6_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS);
	} else
		IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);

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

out:
	IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
	kfree_skb(skb);
}

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_cmp(&psf->sf_addr, psfsrc) == 0)
			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;
}

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_cmp(pmca, &pmc->mca_addr) == 0)
			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_cmp(&psf->sf_addr, psfsrc) == 0)
			break;
		psf_prev = psf;
	}
	if (!psf) {
		psf = (struct ip6_sf_list *)kmalloc(sizeof(*psf), GFP_ATOMIC);
		if (!psf)
			return -ENOBUFS;
		memset(psf, 0, sizeof(*psf));
		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;
	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 != psf->sf_oldin) {
			psf->sf_crcount = qrv;
			rv++;
		}
	}
	return rv;
}

/*
 * Add multicast source filter list to the interface list
 */
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_cmp(pmca, &pmc->mca_addr) == 0)
			break;
	}
	if (!pmc) {
		/* MCA not found?? bug */
		read_unlock_bh(&idev->lock);
		return -ESRCH;
	}
	spin_lock_bh(&pmc->mca_lock);

	sf_markstate(pmc);