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[IPV4]: Fix multiple bugs in IGMPv3
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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>
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David L Stevens authored and David S. Miller committed Jan 18, 2006
1 parent 7ac5459 commit ad12583
Showing 1 changed file with 122 additions and 30 deletions.
152 changes: 122 additions & 30 deletions net/ipv4/igmp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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 */
Expand All @@ -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;
Expand Down Expand Up @@ -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--;
Expand All @@ -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);

Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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);
}
Expand Down Expand Up @@ -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)
Expand All @@ -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)
Expand Down Expand Up @@ -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)
Expand All @@ -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);
}
Expand Down Expand Up @@ -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;
Expand All @@ -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++;
}
}
Expand Down

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