struct dst_ops tracks number of allocated dst in an atomic_t field,
subject to high cache line contention in stress workload.
Switch to a percpu_counter, to reduce number of time we need to dirty a
central location. Place it on a separate cache line to avoid dirtying
read only fields.
Stress test :
(Sending 160.000.000 UDP frames,
IP route cache disabled, dual E5540 @2.53GHz,
32bit kernel, FIB_TRIE, SLUB/NUMA)
Before:
real 0m51.179s
user 0m15.329s
sys 10m15.942s
After:
real 0m45.570s
user 0m15.525s
sys 9m56.669s
With a small reordering of struct neighbour fields, subject of a
following patch, (to separate refcnt from other read mostly fields)
real 0m41.841s
user 0m15.261s
sys 8m45.949s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a seqlock in struct neighbour to protect neigh->ha[], and avoid
dirtying neighbour in stress situation (many different flows / dsts)
Dirtying takes place because of read_lock(&n->lock) and n->used writes.
Switching to a seqlock, and writing n->used only on jiffies changes
permits less dirtying.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit "fib: RCU conversion of fib_lookup()" removed rcu_read_lock() from
__mkroute_output but left a couple of calls to rcu_read_unlock() in there.
This causes lockdep to complain that the rcu_read_unlock() call in
__ip_route_output_key causes a lock inbalance and quickly crashes the
kernel. The below fixes this for me.
Signed-off-by: Dimitris Michailidis <dm@chelsio.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This looks like a simple typo that has gone unnoticed for some time. The
impact is relatively low but it's clearly wrong.
Signed-off-by: John Heffner <johnwheffner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The IGMP specs states that if the system receives a
membership report, it shouldn't send another for the
next minute. However, if a link failure happens right
after that, the backup slave and the switch connected
to this slave will not know about the multicast and
the traffic will hang for about a minute.
This patch fixes it to rejoin multicast groups immediately
after a failover restoring the multicast traffic.
Signed-off-by: Flavio Leitner <fleitner@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
David
This is the first step for RCU conversion of neigh code.
Next patches will convert hash_buckets[] and "struct neighbour" to RCU
protected objects.
Thanks
[PATCH net-next] net neigh: RCU conversion of neigh hash table
Instead of storing hash_buckets, hash_mask and hash_rnd in "struct
neigh_table", a new structure is defined :
struct neigh_hash_table {
struct neighbour **hash_buckets;
unsigned int hash_mask;
__u32 hash_rnd;
struct rcu_head rcu;
};
And "struct neigh_table" has an RCU protected pointer to such a
neigh_hash_table.
This means the signature of (*hash)() function changed: We need to add a
third parameter with the actual hash_rnd value, since this is not
anymore a neigh_table field.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In various situations, a device provides a packet to our stack and we
drop it before it enters protocol stack :
- softnet backlog full (accounted in /proc/net/softnet_stat)
- bad vlan tag (not accounted)
- unknown/unregistered protocol (not accounted)
We can handle a per-device counter of such dropped frames at core level,
and automatically adds it to the device provided stats (rx_dropped), so
that standard tools can be used (ifconfig, ip link, cat /proc/net/dev)
This is a generalization of commit 8990f468a (net: rx_dropped
accounting), thus reverting it.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Code style cleanups before upcoming functional changes.
C99 initializer for fib_props array.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While doing stress tests with IP route cache disabled, and multi queue
devices, I noticed a very high contention on one rwlock used in
neighbour code.
When many cpus are trying to send frames (possibly using a high
performance multiqueue device) to the same neighbour, they fight for the
neigh->lock rwlock in order to call neigh_hh_init(), and fight on
hh->hh_refcnt (a pair of atomic_inc/atomic_dec_and_test())
But we dont need to call neigh_hh_init() for dst that are used only
once. It costs four atomic operations at least, on two contended cache
lines, plus the high contention on neigh->lock rwlock.
Introduce a new dst flag, DST_NOCACHE, that is set when dst was not
inserted in route cache.
With the stress test bench, sending 160000000 frames on one neighbour,
results are :
Before patch:
real 2m28.406s
user 0m11.781s
sys 36m17.964s
After patch:
real 1m26.532s
user 0m12.185s
sys 20m3.903s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A recent patch to allow IGMPv2 responses to IGMPv3 queries
bypasses length checks for valid query lengths, incorrectly
resets the v2_seen timer, and does not support IGMPv1.
The following patch responds with a v2 report as required
by IGMPv2 while correcting the other problems introduced
by the patch.
Signed-Off-By: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use RCU & RTNL protection for mfc_cache_array[]
ipmr_cache_find() is called under rcu_read_lock();
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use RCU and RTNL to protect (struct mr_table)->mroute_sk
Readers use RCU, writers use RTNL.
ip_ra_control() already use an RCU grace period before
ip_ra_destroy_rcu(), so we dont need synchronize_rcu() in
mrtsock_destruct()
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
No need to get a reference on reg_dev and release it, we are in a
rcu_read_lock() protected section.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit e81963b180.
LRO is now deprecated in favour of GRO, and only a few drivers use it,
so it is desirable to build it as a module in distribution kernels.
The original change to prevent building it as a module was made in an
attempt to avoid the case where some dependents are set to y and some
to m, and INET_LRO can be set to m rather than y. However, the
Kconfig system will reliably set INET_LRO=y in this case.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_dev_find(net, addr) finds a device given an IPv4 source address and
takes a reference on it.
Introduce __ip_dev_find(), taking a third argument, to optionally take
the device reference. Callers not asking the reference to be taken
should be in an rcu_read_lock() protected section.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While doing stress tests with a disabled IP route cache, I found
__mkroute_output() was touching three times in_device atomic refcount.
Use RCU to touch it once to reduce cache line ping pongs.
Before patch
time to perform the test
real 1m42.009s
user 0m12.545s
sys 25m0.726s
Profile :
16109.00 26.4% ip_route_output_slow vmlinux
7434.00 12.2% dst_destroy vmlinux
3280.00 5.4% fib_rules_lookup vmlinux
3252.00 5.3% fib_semantic_match vmlinux
2622.00 4.3% fib_table_lookup vmlinux
2535.00 4.1% dst_alloc vmlinux
1750.00 2.9% _raw_read_lock vmlinux
1532.00 2.5% rt_set_nexthop vmlinux
After patch
real 1m36.503s
user 0m12.977s
sys 23m25.608s
14234.00 22.4% ip_route_output_slow vmlinux
8717.00 13.7% dst_destroy vmlinux
4052.00 6.4% fib_rules_lookup vmlinux
3951.00 6.2% fib_semantic_match vmlinux
3191.00 5.0% dst_alloc vmlinux
1764.00 2.8% fib_table_lookup vmlinux
1692.00 2.7% _raw_read_lock vmlinux
1605.00 2.5% rt_set_nexthop vmlinux
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
HARD_TX_LOCK no longer protects tunnels from dead loops,
but xmit_recursion percpu counter.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
IPIP tunnels can benefit from lockless xmits, using NETIF_F_LLTX
Bench on a 16 cpus machine (dual E5540 cpus), 16 threads sending
10000000 UDP frames via one ipip tunnel (size:200 bytes per frame)
Before patch :
real 2m53.321s
user 0m10.277s
sys 46m0.597s
After patch:
real 0m32.063s
user 0m9.237s
sys 8m16.255s
Last problem to solve is the contention on dst :
16118.00 28.3% __ip_route_output_key vmlinux
6135.00 10.8% dst_release vmlinux
3220.00 5.6% ip_finish_output vmlinux
2149.00 3.8% ip_route_output_flow vmlinux
1575.00 2.8% ip_append_data vmlinux
1481.00 2.6% ip_push_pending_frames vmlinux
1349.00 2.4% __xfrm_lookup vmlinux
1216.00 2.1% csum_partial_copy_generic vmlinux
1208.00 2.1% udp_sendmsg vmlinux
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
GRE tunnels can benefit from lockless xmits, using NETIF_F_LLTX
Note: If tunnels are created with the "oseq" option, LLTX is not
enabled :
Even using an atomic_t o_seq, we would increase chance for packets being
out of order at receiver.
Bench on a 16 cpus machine (dual E5540 cpus), 16 threads sending
10000000 UDP frames via one gre tunnel (size:200 bytes per frame)
Before patch :
real 3m0.094s
user 0m9.365s
sys 47m50.103s
After patch:
real 0m29.756s
user 0m11.097s
sys 7m33.012s
Last problem to solve is the contention on dst :
38660.00 21.4% __ip_route_output_key vmlinux
20786.00 11.5% dst_release vmlinux
14191.00 7.8% __xfrm_lookup vmlinux
12410.00 6.9% ip_finish_output vmlinux
4540.00 2.5% ip_push_pending_frames vmlinux
4427.00 2.4% ip_append_data vmlinux
4265.00 2.4% __alloc_skb vmlinux
4140.00 2.3% __ip_local_out vmlinux
3991.00 2.2% dev_queue_xmit vmlinux
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 3c97af99a5 (ipip: percpu stats accounting) forgot the fallback
tunnel case (tunl0), and can crash pretty fast.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch allows a host to be configured to respond to any address in
a specified range as if it were local, without actually needing to
configure the address on an interface. This is done through routing
table configuration. For instance, to configure a host to respond
to any address in 10.1/16 received on eth0 as a local address we can do:
ip rule add from all iif eth0 lookup 200
ip route add local 10.1/16 dev lo proto kernel scope host src 127.0.0.1 table 200
This host is now reachable by any 10.1/16 address (route lookup on
input for packets received on eth0 can find the route). On output, the
rule will not be matched so that this host can still send packets to
10.1/16 (not sent on loopback). Presumably, external routing can be
configured to make sense out of this.
To make this work, we needed to modify the logic in finding the
interface which is assigned a given source address for output
(dev_ip_find). We perform a normal fib_lookup instead of just a
lookup on the local table, and in the lookup we ignore the input
interface for matching.
This patch is useful to implement IP-anycast for subnets of virtual
addresses.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The GRE tunnel driver needs to invoke icmpv6 helpers in the
ipv6 stack when ipv6 support is enabled.
Therefore if IPV6 is enabled, we have to enforce that GRE's
enabling (modular or static) matches that of ipv6.
Reported-by: Patrick McHardy <kaber@trash.net>
Reported-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixes kernel Bugzilla Bug 18952
This patch adds a syn_set parameter to the retransmits_timed_out()
routine and updates its callers. If not set, TCP_RTO_MIN is taken
as the calculation basis as before. If set, TCP_TIMEOUT_INIT is
used instead, so that sysctl_syn_retries represents the actual
amount of SYN retransmissions in case no SYNACKs are received when
establishing a new connection.
Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Maintain per_cpu tx_bytes, tx_packets, rx_bytes, rx_packets.
Other seldom used fields are kept in netdev->stats structure, possibly
unsafe.
This is a preliminary work to support lockless transmit path, and
correct RX stats, that are already unsafe.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Le lundi 27 septembre 2010 à 14:29 +0100, Ben Hutchings a écrit :
> > diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
> > index 5d6ddcb..de39b22 100644
> > --- a/net/ipv4/ip_gre.c
> > +++ b/net/ipv4/ip_gre.c
> [...]
> > @@ -377,7 +405,7 @@ static struct ip_tunnel *ipgre_tunnel_locate(struct net *net,
> > if (parms->name[0])
> > strlcpy(name, parms->name, IFNAMSIZ);
> > else
> > - sprintf(name, "gre%%d");
> > + strcpy(name, "gre%d");
> >
> > dev = alloc_netdev(sizeof(*t), name, ipgre_tunnel_setup);
> > if (!dev)
> [...]
>
> This is a valid fix, but doesn't belong in this patch!
>
Sorry ? It was not a fix, but at most a cleanup ;)
Anyway I forgot the gretap case...
[PATCH 2/4 v2] ip_gre: percpu stats accounting
Maintain per_cpu tx_bytes, tx_packets, rx_bytes, rx_packets.
Other seldom used fields are kept in netdev->stats structure, possibly
unsafe.
This is a preliminary work to support lockless transmit path, and
correct RX stats, that are already unsafe.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixes kernel bugzilla #16603
tcp_sendmsg() truncates iov_len to an 'int' which a 4GB write to write
zero bytes, for example.
There is also the problem higher up of how verify_iovec() works. It
wants to prevent the total length from looking like an error return
value.
However it does this using 'int', but syscalls return 'long' (and
thus signed 64-bit on 64-bit machines). So it could trigger
false-positives on 64-bit as written. So fix it to use 'long'.
Reported-by: Olaf Bonorden <bono@onlinehome.de>
Reported-by: Daniel Büse <dbuese@gmx.de>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
IPv4 and IPv6 have separate neighbour tables, so
the warning messages should be distinguishable.
[ Add a suitable message prefix on the ipv4 side as well -DaveM ]
Signed-off-by: Ulrich Weber <uweber@astaro.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When TCP uses FACK algorithm to mark lost packets in
tcp_mark_head_lost(), if the number of packets in the (TSO) skb is
greater than the number of packets that should be marked lost, TCP
incorrectly exits the loop and marks no packets lost in the skb. This
underestimates tp->lost_out and affects the recovery/retransmission.
This patch fargments the skb and marks the correct amount of packets
lost.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
__in_dev_get_rtnl(dev_out) is called while RTNL is not held, thus
triggers a lockdep fault.
At this point, we only perform a raw test of dev_out->ip_ptr being NULL,
we dont need to make sure ip_ptr cant changed right after.
We can use rcu_dereference_raw() for this.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While investigating a bit, I found ip_fragment() slow path was taken
because ip_append_data() provides following layout for a send(MTU +
N*(MTU - 20)) syscall :
- one skb with 1500 (mtu) bytes
- N fragments of 1480 (mtu-20) bytes (before adding IP header)
last fragment gets 17 bytes of trail data because of following bit:
if (datalen == length + fraggap)
alloclen += rt->dst.trailer_len;
Then esp4 adds 16 bytes of data (while trailer_len is 17... hmm...
another bug ?)
In ip_fragment(), we notice last fragment is too big (1496 + 20) > mtu,
so we take slow path, building another skb chain.
In order to avoid taking slow path, we should correct ip_append_data()
to make sure last fragment has real trail space, under mtu...
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change "return (EXPR);" to "return EXPR;"
return is not a function, parentheses are not required.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
otherwise ECT(1) bit will get interpreted as RTO_ONLINK
and routing will fail with XfrmOutBundleGenError.
Signed-off-by: Ulrich Weber <uweber@astaro.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
we need to check proper socket type within ipv4_conntrack_defrag
function before referencing the nodefrag flag.
For example the tun driver receive path produces skbs with
AF_UNSPEC socket type, and so current code is causing unwanted
fragmented packets going out.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix checksum calculation in nf_nat_snmp_basic.
Based on patches by Clark Wang <wtweeker@163.com> and
Stephen Hemminger <shemminger@vyatta.com>.
https://bugzilla.kernel.org/show_bug.cgi?id=17622
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_route_me_harder can't create the route cache when the outdev is the same
with the indev for the skbs whichout a valid protocol set.
__mkroute_input functions has this check:
1998 if (skb->protocol != htons(ETH_P_IP)) {
1999 /* Not IP (i.e. ARP). Do not create route, if it is
2000 * invalid for proxy arp. DNAT routes are always valid.
2001 *
2002 * Proxy arp feature have been extended to allow, ARP
2003 * replies back to the same interface, to support
2004 * Private VLAN switch technologies. See arp.c.
2005 */
2006 if (out_dev == in_dev &&
2007 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
2008 err = -EINVAL;
2009 goto cleanup;
2010 }
2011 }
This patch gives the new skb a valid protocol to bypass this check. In order
to make ipt_REJECT work with bridges, you also need to enable ip_forward.
This patch also fixes a regression. When we used skb_copy_expand(), we
didn't have this issue stated above, as the protocol was properly set.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Special care should be taken when slow path is hit in ip_fragment() :
When walking through frags, we transfert truesize ownership from skb to
frags. Then if we hit a slow_path condition, we must undo this or risk
uncharging frags->truesize twice, and in the end, having negative socket
sk_wmem_alloc counter, or even freeing socket sooner than expected.
Many thanks to Nick Bowler, who provided a very clean bug report and
test program.
Thanks to Jarek for reviewing my first patch and providing a V2
While Nick bisection pointed to commit 2b85a34e91 (net: No more
expensive sock_hold()/sock_put() on each tx), underlying bug is older
(2.6.12-rc5)
A side effect is to extend work done in commit b2722b1c3a
(ip_fragment: also adjust skb->truesize for packets not owned by a
socket) to ipv6 as well.
Reported-and-bisected-by: Nick Bowler <nbowler@elliptictech.com>
Tested-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Jarek Poplawski <jarkao2@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
If a RST comes in immediately after checking sk->sk_err, tcp_poll will
return POLLIN but not POLLOUT. Fix this by checking sk->sk_err at the end
of tcp_poll. Additionally, ensure the correct order of operations on SMP
machines with memory barriers.
Signed-off-by: Tom Marshall <tdm.code@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The family parameter xfrm_state_find is used to find a state matching a
certain policy. This value is set to the template's family
(encap_family) right before xfrm_state_find is called.
The family parameter is however also used to construct a temporary state
in xfrm_state_find itself which is wrong for inter-family scenarios
because it produces a selector for the wrong family. Since this selector
is included in the xfrm_user_acquire structure, user space programs
misinterpret IPv6 addresses as IPv4 and vice versa.
This patch splits up the original init_tempsel function into a part that
initializes the selector respectively the props and id of the temporary
state, to allow for differing ip address families whithin the state.
Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Under load, netif_rx() can drop incoming packets but administrators dont
have a chance to spot which device needs some tuning (RPS activation for
example)
This patch adds rx_dropped accounting in vlans and tunnels.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6 can be a module, we should test CONFIG_IPV6 and CONFIG_IPV6_MODULE
to enable ipv6 bits in ip_gre.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Related dicussion here : http://lkml.org/lkml/2010/9/3/16
Introduce a function br_parse_ip_options that will audit the
skb and possibly refill IP options before a packet enters the
IP stack. If no options are present, the function will zero out
the skb cb area so that it is not misinterpreted as options by some
unsuspecting IP layer routine. If packet consistency fails, drop it.
Signed-off-by: Bandan Das <bandan.das@stratus.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
dev->ip_ptr is protected by rtnl and rcu.
Yet some places dont use appropriate primitives and/or locking rules.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Dumazet
Dimitris Michailidis
John Heffner
Flavio Leitner
David S. Miller
David Stevens
stephen hemminger
Ben Hutchings
Tom Herbert
Damian Lukowski
Ulrich Weber
Yuchung Cheng
Jiri Olsa
Patrick McHardy
Changli Gao
Tom Marshall
Thomas Egerer
Bandan Das