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ipv6/mcast: init as INCLUDE when join SSM INCLUDE group
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This an IPv6 version patch of "ipv4/igmp: init group mode as INCLUDE when
join source group". From RFC3810, part 6.1:

   If no per-interface state existed for that
   multicast address before the change (i.e., the change consisted of
   creating a new per-interface record), or if no state exists after the
   change (i.e., the change consisted of deleting a per-interface
   record), then the "non-existent" state is considered to have an
   INCLUDE filter mode and an empty source list.

Which means a new multicast group should start with state IN(). Currently,
for MLDv2 SSM JOIN_SOURCE_GROUP mode, we first call ipv6_sock_mc_join(),
then ip6_mc_source(), which will trigger a TO_IN() message instead of
ALLOW().

The issue was exposed by commit a052517 ("net/multicast: should not
send source list records when have filter mode change"). Before this change,
we sent both ALLOW(A) and TO_IN(A). Now, we only send TO_IN(A).

Fix it by adding a new parameter to init group mode. Also add some wrapper
functions to avoid changing too much code.

v1 -> v2:
In the first version I only cleared the group change record. But this is not
enough. Because when a new group join, it will init as EXCLUDE and trigger
a filter mode change in ip/ip6_mc_add_src(), which will clear all source
addresses sf_crcount. This will prevent early joined address sending state
change records if multi source addressed joined at the same time.

In v2 patch, I fixed it by directly initializing the mode to INCLUDE for SSM
JOIN_SOURCE_GROUP. I also split the original patch into two separated patches
for IPv4 and IPv6.

There is also a difference between v4 and v6 version. For IPv6, when the
interface goes down and up, we will send correct state change record with
unspecified IPv6 address (::) with function ipv6_mc_up(). But after DAD is
completed, we resend the change record TO_IN() in mld_send_initial_cr().
Fix it by sending ALLOW() for INCLUDE mode in mld_send_initial_cr().

Fixes: a052517 ("net/multicast: should not send source list records when have filter mode change")
Reviewed-by: Stefano Brivio <[email protected]>
Signed-off-by: Hangbin Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@liuhangbin @davem330
liuhangbin authored and davem330 committed Jul 16, 2018
1 parent 6e2059b commit c7ea20c
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Showing 3 changed files with 50 additions and 21 deletions.
2 changes: 2 additions & 0 deletions include/net/ipv6.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1100,6 +1100,8 @@ void ipv6_sysctl_unregister(void);

int ipv6_sock_mc_join(struct sock *sk, int ifindex,
const struct in6_addr *addr);
int ipv6_sock_mc_join_ssm(struct sock *sk, int ifindex,
const struct in6_addr *addr, unsigned int mode);
int ipv6_sock_mc_drop(struct sock *sk, int ifindex,
const struct in6_addr *addr);
#endif /* _NET_IPV6_H */
5 changes: 3 additions & 2 deletions net/ipv6/ipv6_sockglue.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -729,8 +729,9 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
struct sockaddr_in6 *psin6;

psin6 = (struct sockaddr_in6 *)&greqs.gsr_group;
retv = ipv6_sock_mc_join(sk, greqs.gsr_interface,
&psin6->sin6_addr);
retv = ipv6_sock_mc_join_ssm(sk, greqs.gsr_interface,
&psin6->sin6_addr,
MCAST_INCLUDE);
/* prior join w/ different source is ok */
if (retv && retv != -EADDRINUSE)
break;
Expand Down
64 changes: 45 additions & 19 deletions net/ipv6/mcast.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -95,6 +95,8 @@ static int ip6_mc_add_src(struct inet6_dev *idev, const struct in6_addr *pmca,
int delta);
static int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
struct inet6_dev *idev);
static int __ipv6_dev_mc_inc(struct net_device *dev,
const struct in6_addr *addr, unsigned int mode);

#define MLD_QRV_DEFAULT 2
/* RFC3810, 9.2. Query Interval */
Expand Down Expand Up @@ -132,7 +134,8 @@ static int unsolicited_report_interval(struct inet6_dev *idev)
return iv > 0 ? iv : 1;
}

int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
static int __ipv6_sock_mc_join(struct sock *sk, int ifindex,
const struct in6_addr *addr, unsigned int mode)
{
struct net_device *dev = NULL;
struct ipv6_mc_socklist *mc_lst;
Expand Down Expand Up @@ -179,15 +182,15 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
}

mc_lst->ifindex = dev->ifindex;
mc_lst->sfmode = MCAST_EXCLUDE;
mc_lst->sfmode = mode;
rwlock_init(&mc_lst->sflock);
mc_lst->sflist = NULL;

/*
* now add/increase the group membership on the device
*/

err = ipv6_dev_mc_inc(dev, addr);
err = __ipv6_dev_mc_inc(dev, addr, mode);

if (err) {
sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
Expand All @@ -199,8 +202,19 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)

return 0;
}

int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
{
return __ipv6_sock_mc_join(sk, ifindex, addr, MCAST_EXCLUDE);
}
EXPORT_SYMBOL(ipv6_sock_mc_join);

int ipv6_sock_mc_join_ssm(struct sock *sk, int ifindex,
const struct in6_addr *addr, unsigned int mode)
{
return __ipv6_sock_mc_join(sk, ifindex, addr, mode);
}

/*
* socket leave on multicast group
*/
Expand Down Expand Up @@ -646,7 +660,7 @@ bool inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr,
return rv;
}

static void igmp6_group_added(struct ifmcaddr6 *mc)
static void igmp6_group_added(struct ifmcaddr6 *mc, unsigned int mode)
{
struct net_device *dev = mc->idev->dev;
char buf[MAX_ADDR_LEN];
Expand All @@ -672,7 +686,13 @@ static void igmp6_group_added(struct ifmcaddr6 *mc)
}
/* else v2 */

mc->mca_crcount = mc->idev->mc_qrv;
/* Based on RFC3810 6.1, for newly added INCLUDE SSM, we
* should not send filter-mode change record as the mode
* should be from IN() to IN(A).
*/
if (mode == MCAST_EXCLUDE)
mc->mca_crcount = mc->idev->mc_qrv;

mld_ifc_event(mc->idev);
}

Expand Down Expand Up @@ -770,13 +790,14 @@ static void mld_del_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
spin_lock_bh(&im->mca_lock);
if (pmc) {
im->idev = pmc->idev;
im->mca_crcount = idev->mc_qrv;
im->mca_sfmode = pmc->mca_sfmode;
if (pmc->mca_sfmode == MCAST_INCLUDE) {
im->mca_tomb = pmc->mca_tomb;
im->mca_sources = pmc->mca_sources;
for (psf = im->mca_sources; psf; psf = psf->sf_next)
psf->sf_crcount = im->mca_crcount;
psf->sf_crcount = idev->mc_qrv;
} else {
im->mca_crcount = idev->mc_qrv;
}
in6_dev_put(pmc->idev);
kfree(pmc);
Expand Down Expand Up @@ -831,7 +852,8 @@ static void ma_put(struct ifmcaddr6 *mc)
}

static struct ifmcaddr6 *mca_alloc(struct inet6_dev *idev,
const struct in6_addr *addr)
const struct in6_addr *addr,
unsigned int mode)
{
struct ifmcaddr6 *mc;

Expand All @@ -849,9 +871,8 @@ static struct ifmcaddr6 *mca_alloc(struct inet6_dev *idev,
refcount_set(&mc->mca_refcnt, 1);
spin_lock_init(&mc->mca_lock);

/* initial mode is (EX, empty) */
mc->mca_sfmode = MCAST_EXCLUDE;
mc->mca_sfcount[MCAST_EXCLUDE] = 1;
mc->mca_sfmode = mode;
mc->mca_sfcount[mode] = 1;

if (ipv6_addr_is_ll_all_nodes(&mc->mca_addr) ||
IPV6_ADDR_MC_SCOPE(&mc->mca_addr) < IPV6_ADDR_SCOPE_LINKLOCAL)
Expand All @@ -863,7 +884,8 @@ static struct ifmcaddr6 *mca_alloc(struct inet6_dev *idev,
/*
* device multicast group inc (add if not found)
*/
int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr)
static int __ipv6_dev_mc_inc(struct net_device *dev,
const struct in6_addr *addr, unsigned int mode)
{
struct ifmcaddr6 *mc;
struct inet6_dev *idev;
Expand All @@ -887,14 +909,13 @@ int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr)
if (ipv6_addr_equal(&mc->mca_addr, addr)) {
mc->mca_users++;
write_unlock_bh(&idev->lock);
ip6_mc_add_src(idev, &mc->mca_addr, MCAST_EXCLUDE, 0,
NULL, 0);
ip6_mc_add_src(idev, &mc->mca_addr, mode, 0, NULL, 0);
in6_dev_put(idev);
return 0;
}
}

mc = mca_alloc(idev, addr);
mc = mca_alloc(idev, addr, mode);
if (!mc) {
write_unlock_bh(&idev->lock);
in6_dev_put(idev);
Expand All @@ -911,11 +932,16 @@ int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr)
write_unlock_bh(&idev->lock);

mld_del_delrec(idev, mc);
igmp6_group_added(mc);
igmp6_group_added(mc, mode);
ma_put(mc);
return 0;
}

int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr)
{
return __ipv6_dev_mc_inc(dev, addr, MCAST_EXCLUDE);
}

/*
* device multicast group del
*/
Expand Down Expand Up @@ -1751,7 +1777,7 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,

psf_next = psf->sf_next;

if (!is_in(pmc, psf, type, gdeleted, sdeleted)) {
if (!is_in(pmc, psf, type, gdeleted, sdeleted) && !crsend) {
psf_prev = psf;
continue;
}
Expand Down Expand Up @@ -2066,7 +2092,7 @@ static void mld_send_initial_cr(struct inet6_dev *idev)
if (pmc->mca_sfcount[MCAST_EXCLUDE])
type = MLD2_CHANGE_TO_EXCLUDE;
else
type = MLD2_CHANGE_TO_INCLUDE;
type = MLD2_ALLOW_NEW_SOURCES;
skb = add_grec(skb, pmc, type, 0, 0, 1);
spin_unlock_bh(&pmc->mca_lock);
}
Expand Down Expand Up @@ -2546,7 +2572,7 @@ void ipv6_mc_up(struct inet6_dev *idev)
ipv6_mc_reset(idev);
for (i = idev->mc_list; i; i = i->next) {
mld_del_delrec(idev, i);
igmp6_group_added(i);
igmp6_group_added(i, i->mca_sfmode);
}
read_unlock_bh(&idev->lock);
}
Expand Down

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