igmp.c

linux 内核源代码

		}
		read_unlock(&in_dev->mc_list_lock);
	} else {
		spin_lock_bh(&pmc->lock);
		if (pmc->sfcount[MCAST_EXCLUDE])
			type = IGMPV3_MODE_IS_EXCLUDE;
		else
			type = IGMPV3_MODE_IS_INCLUDE;
		skb = add_grec(skb, pmc, type, 0, 0);
		spin_unlock_bh(&pmc->lock);
	}
	if (!skb)
		return 0;
	return igmpv3_sendpack(skb);
}

/*
 * remove zero-count source records from a source filter list
 */
static void igmpv3_clear_zeros(struct ip_sf_list **ppsf)
{
	struct ip_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 igmpv3_send_cr(struct in_device *in_dev)
{
	struct ip_mc_list *pmc, *pmc_prev, *pmc_next;
	struct sk_buff *skb = NULL;
	int type, dtype;

	read_lock(&in_dev->mc_list_lock);
	spin_lock_bh(&in_dev->mc_tomb_lock);

	/* deleted MCA's */
	pmc_prev = NULL;
	for (pmc=in_dev->mc_tomb; pmc; pmc=pmc_next) {
		pmc_next = pmc->next;
		if (pmc->sfmode == MCAST_INCLUDE) {
			type = IGMPV3_BLOCK_OLD_SOURCES;
			dtype = IGMPV3_BLOCK_OLD_SOURCES;
			skb = add_grec(skb, pmc, type, 1, 0);
			skb = add_grec(skb, pmc, dtype, 1, 1);
		}
		if (pmc->crcount) {
			if (pmc->sfmode == MCAST_EXCLUDE) {
				type = IGMPV3_CHANGE_TO_INCLUDE;
				skb = add_grec(skb, pmc, type, 1, 0);
			}
			pmc->crcount--;
			if (pmc->crcount == 0) {
				igmpv3_clear_zeros(&pmc->tomb);
				igmpv3_clear_zeros(&pmc->sources);
			}
		}
		if (pmc->crcount == 0 && !pmc->tomb && !pmc->sources) {
			if (pmc_prev)
				pmc_prev->next = pmc_next;
			else
				in_dev->mc_tomb = pmc_next;
			in_dev_put(pmc->interface);
			kfree(pmc);
		} else
			pmc_prev = pmc;
	}
	spin_unlock_bh(&in_dev->mc_tomb_lock);

	/* change recs */
	for (pmc=in_dev->mc_list; pmc; pmc=pmc->next) {
		spin_lock_bh(&pmc->lock);
		if (pmc->sfcount[MCAST_EXCLUDE]) {
			type = IGMPV3_BLOCK_OLD_SOURCES;
			dtype = IGMPV3_ALLOW_NEW_SOURCES;
		} else {
			type = IGMPV3_ALLOW_NEW_SOURCES;
			dtype = IGMPV3_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->crcount) {
			if (pmc->sfmode == MCAST_EXCLUDE)
				type = IGMPV3_CHANGE_TO_EXCLUDE;
			else
				type = IGMPV3_CHANGE_TO_INCLUDE;
			skb = add_grec(skb, pmc, type, 0, 0);
			pmc->crcount--;
		}
		spin_unlock_bh(&pmc->lock);
	}
	read_unlock(&in_dev->mc_list_lock);

	if (!skb)
		return;
	(void) igmpv3_sendpack(skb);
}

static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
	int type)
{
	struct sk_buff *skb;
	struct iphdr *iph;
	struct igmphdr *ih;
	struct rtable *rt;
	struct net_device *dev = in_dev->dev;
	__be32	group = pmc ? pmc->multiaddr : 0;
	__be32	dst;

	if (type == IGMPV3_HOST_MEMBERSHIP_REPORT)
		return igmpv3_send_report(in_dev, pmc);
	else if (type == IGMP_HOST_LEAVE_MESSAGE)
		dst = IGMP_ALL_ROUTER;
	else
		dst = group;

	{
		struct flowi fl = { .oif = dev->ifindex,
				    .nl_u = { .ip4_u = { .daddr = dst } },
				    .proto = IPPROTO_IGMP };
		if (ip_route_output_key(&rt, &fl))
			return -1;
	}
	if (rt->rt_src == 0) {
		ip_rt_put(rt);
		return -1;
	}

	skb=alloc_skb(IGMP_SIZE+LL_RESERVED_SPACE(dev), GFP_ATOMIC);
	if (skb == NULL) {
		ip_rt_put(rt);
		return -1;
	}

	skb->dst = &rt->u.dst;

	skb_reserve(skb, LL_RESERVED_SPACE(dev));

	skb_reset_network_header(skb);
	iph = ip_hdr(skb);
	skb_put(skb, sizeof(struct iphdr) + 4);

	iph->version  = 4;
	iph->ihl      = (sizeof(struct iphdr)+4)>>2;
	iph->tos      = 0xc0;
	iph->frag_off = htons(IP_DF);
	iph->ttl      = 1;
	iph->daddr    = dst;
	iph->saddr    = rt->rt_src;
	iph->protocol = IPPROTO_IGMP;
	iph->tot_len  = htons(IGMP_SIZE);
	ip_select_ident(iph, &rt->u.dst, NULL);
	((u8*)&iph[1])[0] = IPOPT_RA;
	((u8*)&iph[1])[1] = 4;
	((u8*)&iph[1])[2] = 0;
	((u8*)&iph[1])[3] = 0;
	ip_send_check(iph);

	ih = (struct igmphdr *)skb_put(skb, sizeof(struct igmphdr));
	ih->type=type;
	ih->code=0;
	ih->csum=0;
	ih->group=group;
	ih->csum=ip_compute_csum((void *)ih, sizeof(struct igmphdr));

	return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev,
		       dst_output);
}

static void igmp_gq_timer_expire(unsigned long data)
{
	struct in_device *in_dev = (struct in_device *)data;

	in_dev->mr_gq_running = 0;
	igmpv3_send_report(in_dev, NULL);
	__in_dev_put(in_dev);
}

static void igmp_ifc_timer_expire(unsigned long data)
{
	struct in_device *in_dev = (struct in_device *)data;

	igmpv3_send_cr(in_dev);
	if (in_dev->mr_ifc_count) {
		in_dev->mr_ifc_count--;
		igmp_ifc_start_timer(in_dev, IGMP_Unsolicited_Report_Interval);
	}
	__in_dev_put(in_dev);
}

static void igmp_ifc_event(struct in_device *in_dev)
{
	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev))
		return;
	in_dev->mr_ifc_count = in_dev->mr_qrv ? in_dev->mr_qrv :
		IGMP_Unsolicited_Report_Count;
	igmp_ifc_start_timer(in_dev, 1);
}


static void igmp_timer_expire(unsigned long data)
{
	struct ip_mc_list *im=(struct ip_mc_list *)data;
	struct in_device *in_dev = im->interface;

	spin_lock(&im->lock);
	im->tm_running=0;

	if (im->unsolicit_count) {
		im->unsolicit_count--;
		igmp_start_timer(im, IGMP_Unsolicited_Report_Interval);
	}
	im->reporter = 1;
	spin_unlock(&im->lock);

	if (IGMP_V1_SEEN(in_dev))
		igmp_send_report(in_dev, im, IGMP_HOST_MEMBERSHIP_REPORT);
	else if (IGMP_V2_SEEN(in_dev))
		igmp_send_report(in_dev, im, IGMPV2_HOST_MEMBERSHIP_REPORT);
	else
		igmp_send_report(in_dev, im, IGMPV3_HOST_MEMBERSHIP_REPORT);

	ip_ma_put(im);
}

/* mark EXCLUDE-mode sources */
static int igmp_xmarksources(struct ip_mc_list *pmc, int nsrcs, __be32 *srcs)
{
	struct ip_sf_list *psf;
	int i, scount;

	scount = 0;
	for (psf=pmc->sources; psf; psf=psf->sf_next) {
		if (scount == nsrcs)
			break;
		for (i=0; i<nsrcs; i++) {
			/* skip inactive filters */
			if (pmc->sfcount[MCAST_INCLUDE] ||
			    pmc->sfcount[MCAST_EXCLUDE] !=
			    psf->sf_count[MCAST_EXCLUDE])
				continue;
			if (srcs[i] == psf->sf_inaddr) {
				scount++;
				break;
			}
		}
	}
	pmc->gsquery = 0;
	if (scount == nsrcs)	/* all sources excluded */
		return 0;
	return 1;
}

static int igmp_marksources(struct ip_mc_list *pmc, int nsrcs, __be32 *srcs)
{
	struct ip_sf_list *psf;
	int i, scount;

	if (pmc->sfmode == MCAST_EXCLUDE)
		return igmp_xmarksources(pmc, nsrcs, srcs);

	/* mark INCLUDE-mode sources */
	scount = 0;
	for (psf=pmc->sources; psf; psf=psf->sf_next) {
		if (scount == nsrcs)
			break;
		for (i=0; i<nsrcs; i++)
			if (srcs[i] == psf->sf_inaddr) {
				psf->sf_gsresp = 1;
				scount++;
				break;
			}
	}
	if (!scount) {
		pmc->gsquery = 0;
		return 0;
	}
	pmc->gsquery = 1;
	return 1;
}

static void igmp_heard_report(struct in_device *in_dev, __be32 group)
{
	struct ip_mc_list *im;

	/* Timers are only set for non-local groups */

	if (group == IGMP_ALL_HOSTS)
		return;

	read_lock(&in_dev->mc_list_lock);
	for (im=in_dev->mc_list; im!=NULL; im=im->next) {
		if (im->multiaddr == group) {
			igmp_stop_timer(im);
			break;
		}
	}
	read_unlock(&in_dev->mc_list_lock);
}

static void igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
	int len)
{
	struct igmphdr 		*ih = igmp_hdr(skb);
	struct igmpv3_query *ih3 = igmpv3_query_hdr(skb);
	struct ip_mc_list	*im;
	__be32			group = ih->group;
	int			max_delay;
	int			mark = 0;


	if (len == 8) {
		if (ih->code == 0) {
			/* Alas, old v1 router presents here. */

			max_delay = IGMP_Query_Response_Interval;
			in_dev->mr_v1_seen = jiffies +
				IGMP_V1_Router_Present_Timeout;
			group = 0;
		} else {
			/* v2 router present */
			max_delay = ih->code*(HZ/IGMP_TIMER_SCALE);
			in_dev->mr_v2_seen = jiffies +
				IGMP_V2_Router_Present_Timeout;
		}
		/* cancel the interface change timer */
		in_dev->mr_ifc_count = 0;
		if (del_timer(&in_dev->mr_ifc_timer))
			__in_dev_put(in_dev);
		/* clear deleted report items */
		igmpv3_clear_delrec(in_dev);
	} else if (len < 12) {
		return;	/* ignore bogus packet; freed by caller */
	} else { /* v3 */
		if (!pskb_may_pull(skb, sizeof(struct igmpv3_query)))
			return;

		ih3 = igmpv3_query_hdr(skb);
		if (ih3->nsrcs) {
			if (!pskb_may_pull(skb, sizeof(struct igmpv3_query)
					   + ntohs(ih3->nsrcs)*sizeof(__be32)))
				return;
			ih3 = igmpv3_query_hdr(skb);
		}

		max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE);
		if (!max_delay)
			max_delay = 1;	/* can't mod w/ 0 */
		in_dev->mr_maxdelay = max_delay;
		if (ih3->qrv)
			in_dev->mr_qrv = ih3->qrv;
		if (!group) { /* general query */
			if (ih3->nsrcs)
				return;	/* no sources allowed */
			igmp_gq_start_timer(in_dev);
			return;
		}
		/* mark sources to include, if group & source-specific */
		mark = ih3->nsrcs != 0;
	}

	/*
	 * - Start the timers in all of our membership records
	 *   that the query applies to for the interface on
	 *   which the query arrived excl. those that belong
	 *   to a "local" group (224.0.0.X)
	 * - For timers already running check if they need to
	 *   be reset.
	 * - Use the igmp->igmp_code field as the maximum
	 *   delay possible
	 */
	read_lock(&in_dev->mc_list_lock);
	for (im=in_dev->mc_list; im!=NULL; im=im->next) {
		int changed;

		if (group && group != im->multiaddr)
			continue;
		if (im->multiaddr == IGMP_ALL_HOSTS)
			continue;
		spin_lock_bh(&im->lock);
		if (im->tm_running)
			im->gsquery = im->gsquery && mark;
		else
			im->gsquery = mark;
		changed = !im->gsquery ||
			igmp_marksources(im, ntohs(ih3->nsrcs), ih3->srcs);
		spin_unlock_bh(&im->lock);
		if (changed)
			igmp_mod_timer(im, max_delay);
	}
	read_unlock(&in_dev->mc_list_lock);
}

int igmp_rcv(struct sk_buff *skb)
{
	/* This basically follows the spec line by line -- see RFC1112 */
	struct igmphdr *ih;
	struct in_device *in_dev = in_dev_get(skb->dev);
	int len = skb->len;

	if (in_dev==NULL) {
		kfree_skb(skb);
		return 0;
	}

	if (!pskb_may_pull(skb, sizeof(struct igmphdr)))
		goto drop;

	switch (skb->ip_summed) {
	case CHECKSUM_COMPLETE:
		if (!csum_fold(skb->csum))
			break;
		/* fall through */
	case CHECKSUM_NONE:
		skb->csum = 0;
		if (__skb_checksum_complete(skb))
			goto drop;
	}

	ih = igmp_hdr(skb);
	switch (ih->type) {
	case IGMP_HOST_MEMBERSHIP_QUERY:
		igmp_heard_query(in_dev, skb, len);
		break;
	case IGMP_HOST_MEMBERSHIP_REPORT:
	case IGMPV2_HOST_MEMBERSHIP_REPORT:
	case IGMPV3_HOST_MEMBERSHIP_REPORT:
		/* Is it our report looped back? */
		if (((struct rtable*)skb->dst)->fl.iif == 0)
			break;
		/* don't rely on MC router hearing unicast reports */
		if (skb->pkt_type == PACKET_MULTICAST ||
		    skb->pkt_type == PACKET_BROADCAST)
			igmp_heard_report(in_dev, ih->group);
		break;
	case IGMP_PIM:
#ifdef CONFIG_IP_PIMSM_V1
		in_dev_put(in_dev);
		return pim_rcv_v1(skb);
#endif
	case IGMP_DVMRP:
	case IGMP_TRACE:
	case IGMP_HOST_LEAVE_MESSAGE:
	case IGMP_MTRACE:
	case IGMP_MTRACE_RESP:
		break;
	default:
		break;
	}

drop:
	in_dev_put(in_dev);
	kfree_skb(skb);
	return 0;
}

#endif


/*
 *	Add a filter to a device
 */

static void ip_mc_filter_add(struct in_device *in_dev, __be32 addr)
{
	char buf[MAX_ADDR_LEN];
	struct net_device *dev = in_dev->dev;

	/* Checking for IFF_MULTICAST here is WRONG-WRONG-WRONG.
	   We will get multicast token leakage, when IFF_MULTICAST
	   is changed. This check should be done in dev->set_multicast_list
	   routine. Something sort of:
	   if (dev->mc_list && dev->flags&IFF_MULTICAST) { do it; }
	   --ANK
	   */
	if (arp_mc_map(addr, buf, dev, 0) == 0)
		dev_mc_add(dev,buf,dev->addr_len,0);
}

/*
 *	Remove a filter from a device
 */

static void ip_mc_filter_del(struct in_device *in_dev, __be32 addr)
{
	char buf[MAX_ADDR_LEN];
	struct net_device *dev = in_dev->dev;

	if (arp_mc_map(addr, buf, dev, 0) == 0)
		dev_mc_delete(dev,buf,dev->addr_len,0);
}

#ifdef CONFIG_IP_MULTICAST
/*
 * deleted ip_mc_list manipulation
 */
static void igmpv3_add_delrec(struct in_device *in_dev, struct ip_mc_list *im)
{
	struct ip_mc_list *pmc;

	/* this is an "ip_mc_list" for convenience; only the fields below
	 * are actually used. In particular, the refcnt and users are not
	 * used for management of the delete list. Using the same structure
	 * for deleted items allows change reports to use common code with
	 * non-deleted or query-response MCA's.
	 */
	pmc = kzalloc(sizeof(*pmc), GFP_KERNEL);
	if (!pmc)