[IPV4]: Fix multiple bugs in IGMPv3

1) fix "mld_marksources()" to
        a) send nothing when all queried sources are excluded
        b) send full exclude report when source queried sources are
                not excluded
        c) don't schedule a timer when there's nothing to report

2) fix "add_grec()" to send empty-source records when it should
        The original check doesn't account for a non-empty source
        list with all sources inactive; the new code keeps that
        short-circuit case, and also generates the group header
        with an empty list if needed.

3) fix mca_crcount decrement to be after add_grec(), which needs
        its original value

4) add/remove delete records and prevent current advertisements
        when an exclude-mode filter moves from "active" to "inactive"
        or vice versa based on new filter additions.

        Items 1-3 are just IPv4 versions of the IPv6 bugs found
by Yan Zheng and fixed earlier. Item #4 is a related bug that
affects exclude-mode change records only (but not queries) and
also occurs in IPv6 (IPv6 version coming soon).

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 192092b..d8ce713 100644 (file)
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -233,7 +233,18 @@ static int is_in(struct ip_mc_list *pmc, struct ip_sf_list *psf, int type,
        case IGMPV3_MODE_IS_EXCLUDE:
                if (gdeleted || sdeleted)
                        return 0;
-               return !(pmc->gsquery && !psf->sf_gsresp);
+               if (!(pmc->gsquery && !psf->sf_gsresp)) {
+                       if (pmc->sfmode == MCAST_INCLUDE)
+                               return 1;
+                       /* don't include if this source is excluded
+                        * in all filters
+                        */
+                       if (psf->sf_count[MCAST_INCLUDE])
+                               return type == IGMPV3_MODE_IS_INCLUDE;
+                       return pmc->sfcount[MCAST_EXCLUDE] ==
+                               psf->sf_count[MCAST_EXCLUDE];
+               }
+               return 0;
        case IGMPV3_CHANGE_TO_INCLUDE:
                if (gdeleted || sdeleted)
                        return 0;
@@ -385,7 +396,7 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
        struct igmpv3_report *pih;
        struct igmpv3_grec *pgr = NULL;
        struct ip_sf_list *psf, *psf_next, *psf_prev, **psf_list;
-       int scount, first, isquery, truncate;
+       int scount, stotal, first, isquery, truncate;
 
        if (pmc->multiaddr == IGMP_ALL_HOSTS)
                return skb;
@@ -395,25 +406,13 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
        truncate = type == IGMPV3_MODE_IS_EXCLUDE ||
                    type == IGMPV3_CHANGE_TO_EXCLUDE;
 
+       stotal = scount = 0;
+
        psf_list = sdeleted ? &pmc->tomb : &pmc->sources;
 
-       if (!*psf_list) {
-               if (type == IGMPV3_ALLOW_NEW_SOURCES ||
-                   type == IGMPV3_BLOCK_OLD_SOURCES)
-                       return skb;
-               if (pmc->crcount || isquery) {
-                       /* make sure we have room for group header and at
-                        * least one source.
-                        */
-                       if (skb && AVAILABLE(skb) < sizeof(struct igmpv3_grec)+
-                           sizeof(__u32)) {
-                               igmpv3_sendpack(skb);
-                               skb = NULL; /* add_grhead will get a new one */
-                       }
-                       skb = add_grhead(skb, pmc, type, &pgr);
-               }
-               return skb;
-       }
+       if (!*psf_list)
+               goto empty_source;
+
        pih = skb ? (struct igmpv3_report *)skb->h.igmph : NULL;
 
        /* EX and TO_EX get a fresh packet, if needed */
@@ -426,7 +425,6 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
                }
        }
        first = 1;
-       scount = 0;
        psf_prev = NULL;
        for (psf=*psf_list; psf; psf=psf_next) {
                u32 *psrc;
@@ -460,7 +458,7 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
                }
                psrc = (u32 *)skb_put(skb, sizeof(u32));
                *psrc = psf->sf_inaddr;
-               scount++;
+               scount++; stotal++;
                if ((type == IGMPV3_ALLOW_NEW_SOURCES ||
                     type == IGMPV3_BLOCK_OLD_SOURCES) && psf->sf_crcount) {
                        psf->sf_crcount--;
@@ -475,6 +473,21 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
                }
                psf_prev = psf;
        }
+
+empty_source:
+       if (!stotal) {
+               if (type == IGMPV3_ALLOW_NEW_SOURCES ||
+                   type == IGMPV3_BLOCK_OLD_SOURCES)
+                       return skb;
+               if (pmc->crcount || isquery) {
+                       /* make sure we have room for group header */
+                       if (skb && AVAILABLE(skb)<sizeof(struct igmpv3_grec)) {
+                               igmpv3_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);
 
@@ -557,11 +570,11 @@ static void igmpv3_send_cr(struct in_device *in_dev)
                        skb = add_grec(skb, pmc, dtype, 1, 1);
                }
                if (pmc->crcount) {
-                       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);
@@ -594,12 +607,12 @@ static void igmpv3_send_cr(struct in_device *in_dev)
 
                /* filter mode changes */
                if (pmc->crcount) {
-                       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);
        }
@@ -735,11 +748,43 @@ static void igmp_timer_expire(unsigned long data)
        ip_ma_put(im);
 }
 
-static void igmp_marksources(struct ip_mc_list *pmc, int nsrcs, __u32 *srcs)
+/* mark EXCLUDE-mode sources */
+static int igmp_xmarksources(struct ip_mc_list *pmc, int nsrcs, __u32 *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, __u32 *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)
@@ -751,6 +796,12 @@ static void igmp_marksources(struct ip_mc_list *pmc, int nsrcs, __u32 *srcs)
                                break;
                        }
        }
+       if (!scount) {
+               pmc->gsquery = 0;
+               return 0;
+       }
+       pmc->gsquery = 1;
+       return 1;
 }
 
 static void igmp_heard_report(struct in_device *in_dev, u32 group)
@@ -845,6 +896,8 @@ static void igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
         */
        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)
@@ -854,10 +907,11 @@ static void igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
                        im->gsquery = im->gsquery && mark;
                else
                        im->gsquery = mark;
-               if (im->gsquery)
-                       igmp_marksources(im, ntohs(ih3->nsrcs), ih3->srcs);
+               changed = !im->gsquery ||
+                       igmp_marksources(im, ntohs(ih3->nsrcs), ih3->srcs);
                spin_unlock_bh(&im->lock);
-               igmp_mod_timer(im, max_delay);
+               if (changed)
+                       igmp_mod_timer(im, max_delay);
        }
        read_unlock(&in_dev->mc_list_lock);
 }
@@ -1510,7 +1564,7 @@ static void sf_markstate(struct ip_mc_list *pmc)
 
 static int sf_setstate(struct ip_mc_list *pmc)
 {
-       struct ip_sf_list *psf;
+       struct ip_sf_list *psf, *dpsf;
        int mca_xcount = pmc->sfcount[MCAST_EXCLUDE];
        int qrv = pmc->interface->mr_qrv;
        int new_in, rv;
@@ -1522,8 +1576,46 @@ static int sf_setstate(struct ip_mc_list *pmc)
                                !psf->sf_count[MCAST_INCLUDE];
                } else
                        new_in = psf->sf_count[MCAST_INCLUDE] != 0;
-               if (new_in != psf->sf_oldin) {
-                       psf->sf_crcount = qrv;
+               if (new_in) {
+                       if (!psf->sf_oldin) {
+                               struct ip_sf_list *prev = 0;
+
+                               for (dpsf=pmc->tomb; dpsf; dpsf=dpsf->sf_next) {
+                                       if (dpsf->sf_inaddr == psf->sf_inaddr)
+                                               break;
+                                       prev = dpsf;
+                               }
+                               if (dpsf) {
+                                       if (prev)
+                                               prev->sf_next = dpsf->sf_next;
+                                       else
+                                               pmc->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->tomb; dpsf; dpsf=dpsf->sf_next)
+                               if (dpsf->sf_inaddr == psf->sf_inaddr)
+                                       break;
+                       if (!dpsf) {
+                               dpsf = (struct ip_sf_list *)
+                                       kmalloc(sizeof(*dpsf), GFP_ATOMIC);
+                               if (!dpsf)
+                                       continue;
+                               *dpsf = *psf;
+                               /* pmc->lock held by callers */
+                               dpsf->sf_next = pmc->tomb;
+                               pmc->tomb = dpsf;
+                       }
+                       dpsf->sf_crcount = qrv;
                        rv++;
                }
        }