net: Add compat ioctl support for the ipv4 multicast ioctl SIOCGETSGCNT

SIOCGETSGCNT is not a unique ioctl value as it it maps tio SIOCPROTOPRIVATE +1,
which unfortunately means the existing infrastructure for compat networking
ioctls is insufficient.  A trivial compact ioctl implementation would conflict
with:

SIOCAX25ADDUID
SIOCAIPXPRISLT
SIOCGETSGCNT_IN6
SIOCGETSGCNT
SIOCRSSCAUSE
SIOCX25SSUBSCRIP
SIOCX25SDTEFACILITIES

To make this work I have updated the compat_ioctl decode path to mirror the
the normal ioctl decode path.  I have added an ipv4 inet_compat_ioctl function
so that I can have ipv4 specific compat ioctls.   I have added a compat_ioctl
function into struct proto so I can break out ioctls by which kind of ip socket
I am using.  I have added a compat_raw_ioctl function because SIOCGETSGCNT only
works on raw sockets.  I have added a ipmr_compat_ioctl that mirrors the normal
ipmr_ioctl.

This was necessary because unfortunately the struct layout for the SIOCGETSGCNT
has unsigned longs in it so changes between 32bit and 64bit kernels.

This change was sufficient to run a 32bit ip multicast routing daemon on a
64bit kernel.

Reported-by: Bill Fenner <fenner@aristanetworks.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 46 insertions, 0 deletions

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 3f3a9afd73e0..7e41ac0b9260 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -60,6 +60,7 @@
 #include <linux/notifier.h>
 #include <linux/if_arp.h>
 #include <linux/netfilter_ipv4.h>
+#include <linux/compat.h>
 #include <net/ipip.h>
 #include <net/checksum.h>
 #include <net/netlink.h>
@@ -1434,6 +1435,51 @@ int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
         }
 }
 
+#ifdef CONFIG_COMPAT
+struct compat_sioc_sg_req {
+        struct in_addr src;
+        struct in_addr grp;
+        compat_ulong_t pktcnt;
+        compat_ulong_t bytecnt;
+        compat_ulong_t wrong_if;
+};
+
+int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+        struct sioc_sg_req sr;
+        struct mfc_cache *c;
+        struct net *net = sock_net(sk);
+        struct mr_table *mrt;
+
+        mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);
+        if (mrt == NULL)
+                return -ENOENT;
+
+        switch (cmd) {
+        case SIOCGETSGCNT:
+                if (copy_from_user(&sr, arg, sizeof(sr)))
+                        return -EFAULT;
+
+                rcu_read_lock();
+                c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr);
+                if (c) {
+                        sr.pktcnt = c->mfc_un.res.pkt;
+                        sr.bytecnt = c->mfc_un.res.bytes;
+                        sr.wrong_if = c->mfc_un.res.wrong_if;
+                        rcu_read_unlock();
+
+                        if (copy_to_user(arg, &sr, sizeof(sr)))
+                                return -EFAULT;
+                        return 0;
+                }
+                rcu_read_unlock();
+                return -EADDRNOTAVAIL;
+        default:
+                return -ENOIOCTLCMD;
+        }
+}
+#endif
+
 
 static int ipmr_device_event(struct notifier_block *this, unsigned long event, void *ptr)
 {