Now when __sctp_lookup_association is running in BH, it will try to
check if t->dead is set, but meanwhile other CPUs may be freeing this
transport and this assoc and if it happens that
__sctp_lookup_association checked t->dead a bit too early, it may think
that the association is still good while it was already freed.
So we fix this race by using atomic_add_unless in sctp_transport_hold.
After we get one transport from hashtable, we will hold it only when
this transport's refcnt is not 0, so that we can make sure t->asoc
cannot be freed before we hold the asoc again.
Note that sctp association is not freed using RCU so we can't use
atomic_add_unless() with it as it may just be too late for that either.
Fixes: 4f00878126 ("sctp: apply rhashtable api to send/recv path")
Reported-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
transport hashtable will replace the association hashtable,
so association hashtable is not used in sctp any more, so
drop the codes about that.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tranport hashtbale will replace the association hashtable to do the
lookup for transport, and then get association by t->assoc, rhashtable
apis will be used because of it's resizable, scalable and using rcu.
lport + rport + paddr will be the base hashkey to locate the chain,
with net to protect one netns from another, then plus the laddr to
compare to get the target.
this patch will provider the lookup functions:
- sctp_epaddr_lookup_transport
- sctp_addrs_lookup_transport
hash/unhash functions:
- sctp_hash_transport
- sctp_unhash_transport
init/destroy functions:
- sctp_transport_hashtable_init
- sctp_transport_hashtable_destroy
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
when A sends a data to B, then A close() and enter into SHUTDOWN_PENDING
state, if B neither claim his rwnd is 0 nor send SACK for this data, A
will keep retransmitting this data until t5 timeout, Max.Retrans times
can't work anymore, which is bad.
if B's rwnd is not 0, it should send abort after Max.Retrans times, only
when B's rwnd == 0 and A's retransmitting beyonds Max.Retrans times, A
will start t5 timer, which is also commit f8d9605243 ("sctp: Enforce
retransmission limit during shutdown") means, but it lacks the condition
peer rwnd == 0.
so fix it by adding a bit (zero_window_announced) in peer to record if
the last rwnd is 0. If it was, zero_window_announced will be set. and use
this bit to decide if start t5 timer when local.state is SHUTDOWN_PENDING.
Fixes: commit f8d9605243 ("sctp: Enforce retransmission limit during shutdown")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
They don't need to be any bigger than that and with this we start a new
bitfield for tracking association runtime stuff, like zero window
situation.
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
->auto_asconf_splist is per namespace and mangled by functions like
sctp_setsockopt_auto_asconf() which doesn't guarantee any serialization.
Also, the call to inet_sk_copy_descendant() was backuping
->auto_asconf_list through the copy but was not honoring
->do_auto_asconf, which could lead to list corruption if it was
different between both sockets.
This commit thus fixes the list handling by using ->addr_wq_lock
spinlock to protect the list. A special handling is done upon socket
creation and destruction for that. Error handlig on sctp_init_sock()
will never return an error after having initialized asconf, so
sctp_destroy_sock() can be called without addrq_wq_lock. The lock now
will be take on sctp_close_sock(), before locking the socket, so we
don't do it in inverse order compared to sctp_addr_wq_timeout_handler().
Instead of taking the lock on sctp_sock_migrate() for copying and
restoring the list values, it's preferred to avoid rewritting it by
implementing sctp_copy_descendant().
Issue was found with a test application that kept flipping sysctl
default_auto_asconf on and off, but one could trigger it by issuing
simultaneous setsockopt() calls on multiple sockets or by
creating/destroying sockets fast enough. This is only triggerable
locally.
Fixes: 9f7d653b67 ("sctp: Add Auto-ASCONF support (core).")
Reported-by: Ji Jianwen <jiji@redhat.com>
Suggested-by: Neil Horman <nhorman@tuxdriver.com>
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_addr_is_valid() only appeared in its definition.
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Sébastien Barré <sebastien.barre@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
The SCTP socket extensions API document describes the v4mapping option as
follows:
8.1.15. Set/Clear IPv4 Mapped Addresses (SCTP_I_WANT_MAPPED_V4_ADDR)
This socket option is a Boolean flag which turns on or off the
mapping of IPv4 addresses. If this option is turned on, then IPv4
addresses will be mapped to V6 representation. If this option is
turned off, then no mapping will be done of V4 addresses and a user
will receive both PF_INET6 and PF_INET type addresses on the socket.
See [RFC3542] for more details on mapped V6 addresses.
This description isn't really in line with what the code does though.
Introduce addr_to_user (renamed addr_v4map), which should be called
before any sockaddr is passed back to user space. The new function
places the sockaddr into the correct format depending on the
SCTP_I_WANT_MAPPED_V4_ADDR option.
Audit all places that touched v4mapped and either sanely construct
a v4 or v6 address then call addr_to_user, or drop the
unnecessary v4mapped check entirely.
Audit all places that call addr_to_user and verify they are on a sycall
return path.
Add a custom getname that formats the address properly.
Several bugs are addressed:
- SCTP_I_WANT_MAPPED_V4_ADDR=0 often returned garbage for
addresses to user space
- The addr_len returned from recvmsg was not correct when
returning AF_INET on a v6 socket
- flowlabel and scope_id were not zerod when promoting
a v4 to v6
- Some syscalls like bind and connect behaved differently
depending on v4mapped
Tested bind, getpeername, getsockname, connect, and recvmsg for proper
behaviour in v4mapped = 1 and 0 cases.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements section 5.3.6. of RFC6458, that is, support
for 'SCTP Next Receive Information Structure' (SCTP_NXTINFO) which
is placed into ancillary data cmsghdr structure for each recvmsg()
call, if this information is already available when delivering the
current message.
This option can be enabled/disabled via setsockopt(2) on SOL_SCTP
level by setting an int value with 1/0 for SCTP_RECVNXTINFO in
user space applications as per RFC6458, section 8.1.30.
The sctp_nxtinfo structure is defined as per RFC as below ...
struct sctp_nxtinfo {
uint16_t nxt_sid;
uint16_t nxt_flags;
uint32_t nxt_ppid;
uint32_t nxt_length;
sctp_assoc_t nxt_assoc_id;
};
... and provided under cmsg_level IPPROTO_SCTP, cmsg_type
SCTP_NXTINFO, while cmsg_data[] contains struct sctp_nxtinfo.
Joint work with Daniel Borkmann.
Signed-off-by: Geir Ola Vaagland <geirola@gmail.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements section 5.3.5. of RFC6458, that is, support
for 'SCTP Receive Information Structure' (SCTP_RCVINFO) which is
placed into ancillary data cmsghdr structure for each recvmsg()
call.
This option can be enabled/disabled via setsockopt(2) on SOL_SCTP
level by setting an int value with 1/0 for SCTP_RECVRCVINFO in user
space applications as per RFC6458, section 8.1.29.
The sctp_rcvinfo structure is defined as per RFC as below ...
struct sctp_rcvinfo {
uint16_t rcv_sid;
uint16_t rcv_ssn;
uint16_t rcv_flags;
<-- 2 bytes hole -->
uint32_t rcv_ppid;
uint32_t rcv_tsn;
uint32_t rcv_cumtsn;
uint32_t rcv_context;
sctp_assoc_t rcv_assoc_id;
};
... and provided under cmsg_level IPPROTO_SCTP, cmsg_type
SCTP_RCVINFO, while cmsg_data[] contains struct sctp_rcvinfo.
An sctp_rcvinfo item always corresponds to the data in msg_iov.
Joint work with Daniel Borkmann.
Signed-off-by: Geir Ola Vaagland <geirola@gmail.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements section 5.3.4. of RFC6458, that is, support
for 'SCTP Send Information Structure' (SCTP_SNDINFO) which can be
placed into ancillary data cmsghdr structure for sendmsg() calls.
The sctp_sndinfo structure is defined as per RFC as below ...
struct sctp_sndinfo {
uint16_t snd_sid;
uint16_t snd_flags;
uint32_t snd_ppid;
uint32_t snd_context;
sctp_assoc_t snd_assoc_id;
};
... and supplied under cmsg_level IPPROTO_SCTP, cmsg_type
SCTP_SNDINFO, while cmsg_data[] contains struct sctp_sndinfo.
An sctp_sndinfo item always corresponds to the data in msg_iov.
Joint work with Daniel Borkmann.
Signed-off-by: Geir Ola Vaagland <geirola@gmail.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Be more precise in transport path selection and use ktime
helpers instead of jiffies to compare and pick the better
primary and secondary recently used transports. This also
avoids any side-effects during a possible roll-over, and
could lead to better path decision-making.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, it is possible to create an SCTP socket, then switch
auth_enable via sysctl setting to 1 and crash the system on connect:
Oops[#1]:
CPU: 0 PID: 0 Comm: swapper Not tainted 3.14.1-mipsgit-20140415 #1
task: ffffffff8056ce80 ti: ffffffff8055c000 task.ti: ffffffff8055c000
[...]
Call Trace:
[<ffffffff8043c4e8>] sctp_auth_asoc_set_default_hmac+0x68/0x80
[<ffffffff8042b300>] sctp_process_init+0x5e0/0x8a4
[<ffffffff8042188c>] sctp_sf_do_5_1B_init+0x234/0x34c
[<ffffffff804228c8>] sctp_do_sm+0xb4/0x1e8
[<ffffffff80425a08>] sctp_endpoint_bh_rcv+0x1c4/0x214
[<ffffffff8043af68>] sctp_rcv+0x588/0x630
[<ffffffff8043e8e8>] sctp6_rcv+0x10/0x24
[<ffffffff803acb50>] ip6_input+0x2c0/0x440
[<ffffffff8030fc00>] __netif_receive_skb_core+0x4a8/0x564
[<ffffffff80310650>] process_backlog+0xb4/0x18c
[<ffffffff80313cbc>] net_rx_action+0x12c/0x210
[<ffffffff80034254>] __do_softirq+0x17c/0x2ac
[<ffffffff800345e0>] irq_exit+0x54/0xb0
[<ffffffff800075a4>] ret_from_irq+0x0/0x4
[<ffffffff800090ec>] rm7k_wait_irqoff+0x24/0x48
[<ffffffff8005e388>] cpu_startup_entry+0xc0/0x148
[<ffffffff805a88b0>] start_kernel+0x37c/0x398
Code: dd0900b8 000330f8 0126302d <dcc60000> 50c0fff1 0047182a a48306a0
03e00008 00000000
---[ end trace b530b0551467f2fd ]---
Kernel panic - not syncing: Fatal exception in interrupt
What happens while auth_enable=0 in that case is, that
ep->auth_hmacs is initialized to NULL in sctp_auth_init_hmacs()
when endpoint is being created.
After that point, if an admin switches over to auth_enable=1,
the machine can crash due to NULL pointer dereference during
reception of an INIT chunk. When we enter sctp_process_init()
via sctp_sf_do_5_1B_init() in order to respond to an INIT chunk,
the INIT verification succeeds and while we walk and process
all INIT params via sctp_process_param() we find that
net->sctp.auth_enable is set, therefore do not fall through,
but invoke sctp_auth_asoc_set_default_hmac() instead, and thus,
dereference what we have set to NULL during endpoint
initialization phase.
The fix is to make auth_enable immutable by caching its value
during endpoint initialization, so that its original value is
being carried along until destruction. The bug seems to originate
from the very first days.
Fix in joint work with Daniel Borkmann.
Reported-by: Joshua Kinard <kumba@gentoo.org>
Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Tested-by: Joshua Kinard <kumba@gentoo.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implementation of (a)rwnd calculation might lead to severe performance issues
and associations completely stalling. These problems are described and solution
is proposed which improves lksctp's robustness in congestion state.
1) Sudden drop of a_rwnd and incomplete window recovery afterwards
Data accounted in sctp_assoc_rwnd_decrease takes only payload size (sctp data),
but size of sk_buff, which is blamed against receiver buffer, is not accounted
in rwnd. Theoretically, this should not be the problem as actual size of buffer
is double the amount requested on the socket (SO_RECVBUF). Problem here is
that this will have bad scaling for data which is less then sizeof sk_buff.
E.g. in 4G (LTE) networks, link interfacing radio side will have a large portion
of traffic of this size (less then 100B).
An example of sudden drop and incomplete window recovery is given below. Node B
exhibits problematic behavior. Node A initiates association and B is configured
to advertise rwnd of 10000. A sends messages of size 43B (size of typical sctp
message in 4G (LTE) network). On B data is left in buffer by not reading socket
in userspace.
Lets examine when we will hit pressure state and declare rwnd to be 0 for
scenario with above stated parameters (rwnd == 10000, chunk size == 43, each
chunk is sent in separate sctp packet)
Logic is implemented in sctp_assoc_rwnd_decrease:
socket_buffer (see below) is maximum size which can be held in socket buffer
(sk_rcvbuf). current_alloced is amount of data currently allocated (rx_count)
A simple expression is given for which it will be examined after how many
packets for above stated parameters we enter pressure state:
We start by condition which has to be met in order to enter pressure state:
socket_buffer < currently_alloced;
currently_alloced is represented as size of sctp packets received so far and not
yet delivered to userspace. x is the number of chunks/packets (since there is no
bundling, and each chunk is delivered in separate packet, we can observe each
chunk also as sctp packet, and what is important here, having its own sk_buff):
socket_buffer < x*each_sctp_packet;
each_sctp_packet is sctp chunk size + sizeof(struct sk_buff). socket_buffer is
twice the amount of initially requested size of socket buffer, which is in case
of sctp, twice the a_rwnd requested:
2*rwnd < x*(payload+sizeof(struc sk_buff));
sizeof(struct sk_buff) is 190 (3.13.0-rc4+). Above is stated that rwnd is 10000
and each payload size is 43
20000 < x(43+190);
x > 20000/233;
x ~> 84;
After ~84 messages, pressure state is entered and 0 rwnd is advertised while
received 84*43B ~= 3612B sctp data. This is why external observer notices sudden
drop from 6474 to 0, as it will be now shown in example:
IP A.34340 > B.12345: sctp (1) [INIT] [init tag: 1875509148] [rwnd: 81920] [OS: 10] [MIS: 65535] [init TSN: 1096057017]
IP B.12345 > A.34340: sctp (1) [INIT ACK] [init tag: 3198966556] [rwnd: 10000] [OS: 10] [MIS: 10] [init TSN: 902132839]
IP A.34340 > B.12345: sctp (1) [COOKIE ECHO]
IP B.12345 > A.34340: sctp (1) [COOKIE ACK]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057017] [SID: 0] [SSEQ 0] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057017] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057018] [SID: 0] [SSEQ 1] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057018] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057019] [SID: 0] [SSEQ 2] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057019] [a_rwnd 9914] [#gap acks 0] [#dup tsns 0]
<...>
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057098] [SID: 0] [SSEQ 81] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057098] [a_rwnd 6517] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057099] [SID: 0] [SSEQ 82] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057099] [a_rwnd 6474] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057100] [SID: 0] [SSEQ 83] [PPID 0x18]
--> Sudden drop
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
At this point, rwnd_press stores current rwnd value so it can be later restored
in sctp_assoc_rwnd_increase. This however doesn't happen as condition to start
slowly increasing rwnd until rwnd_press is returned to rwnd is never met. This
condition is not met since rwnd, after it hit 0, must first reach rwnd_press by
adding amount which is read from userspace. Let us observe values in above
example. Initial a_rwnd is 10000, pressure was hit when rwnd was ~6500 and the
amount of actual sctp data currently waiting to be delivered to userspace
is ~3500. When userspace starts to read, sctp_assoc_rwnd_increase will be blamed
only for sctp data, which is ~3500. Condition is never met, and when userspace
reads all data, rwnd stays on 3569.
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 1505] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 3010] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057101] [SID: 0] [SSEQ 84] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057101] [a_rwnd 3569] [#gap acks 0] [#dup tsns 0]
--> At this point userspace read everything, rwnd recovered only to 3569
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057102] [SID: 0] [SSEQ 85] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057102] [a_rwnd 3569] [#gap acks 0] [#dup tsns 0]
Reproduction is straight forward, it is enough for sender to send packets of
size less then sizeof(struct sk_buff) and receiver keeping them in its buffers.
2) Minute size window for associations sharing the same socket buffer
In case multiple associations share the same socket, and same socket buffer
(sctp.rcvbuf_policy == 0), different scenarios exist in which congestion on one
of the associations can permanently drop rwnd of other association(s).
Situation will be typically observed as one association suddenly having rwnd
dropped to size of last packet received and never recovering beyond that point.
Different scenarios will lead to it, but all have in common that one of the
associations (let it be association from 1)) nearly depleted socket buffer, and
the other association blames socket buffer just for the amount enough to start
the pressure. This association will enter pressure state, set rwnd_press and
announce 0 rwnd.
When data is read by userspace, similar situation as in 1) will occur, rwnd will
increase just for the size read by userspace but rwnd_press will be high enough
so that association doesn't have enough credit to reach rwnd_press and restore
to previous state. This case is special case of 1), being worse as there is, in
the worst case, only one packet in buffer for which size rwnd will be increased.
Consequence is association which has very low maximum rwnd ('minute size', in
our case down to 43B - size of packet which caused pressure) and as such
unusable.
Scenario happened in the field and labs frequently after congestion state (link
breaks, different probabilities of packet drop, packet reordering) and with
scenario 1) preceding. Here is given a deterministic scenario for reproduction:
>From node A establish two associations on the same socket, with rcvbuf_policy
being set to share one common buffer (sctp.rcvbuf_policy == 0). On association 1
repeat scenario from 1), that is, bring it down to 0 and restore up. Observe
scenario 1). Use small payload size (here we use 43). Once rwnd is 'recovered',
bring it down close to 0, as in just one more packet would close it. This has as
a consequence that association number 2 is able to receive (at least) one more
packet which will bring it in pressure state. E.g. if association 2 had rwnd of
10000, packet received was 43, and we enter at this point into pressure,
rwnd_press will have 9957. Once payload is delivered to userspace, rwnd will
increase for 43, but conditions to restore rwnd to original state, just as in
1), will never be satisfied.
--> Association 1, between A.y and B.12345
IP A.55915 > B.12345: sctp (1) [INIT] [init tag: 836880897] [rwnd: 10000] [OS: 10] [MIS: 65535] [init TSN: 4032536569]
IP B.12345 > A.55915: sctp (1) [INIT ACK] [init tag: 2873310749] [rwnd: 81920] [OS: 10] [MIS: 10] [init TSN: 3799315613]
IP A.55915 > B.12345: sctp (1) [COOKIE ECHO]
IP B.12345 > A.55915: sctp (1) [COOKIE ACK]
--> Association 2, between A.z and B.12346
IP A.55915 > B.12346: sctp (1) [INIT] [init tag: 534798321] [rwnd: 10000] [OS: 10] [MIS: 65535] [init TSN: 2099285173]
IP B.12346 > A.55915: sctp (1) [INIT ACK] [init tag: 516668823] [rwnd: 81920] [OS: 10] [MIS: 10] [init TSN: 3676403240]
IP A.55915 > B.12346: sctp (1) [COOKIE ECHO]
IP B.12346 > A.55915: sctp (1) [COOKIE ACK]
--> Deplete socket buffer by sending messages of size 43B over association 1
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315613] [SID: 0] [SSEQ 0] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315613] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
<...>
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315696] [a_rwnd 6388] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315697] [SID: 0] [SSEQ 84] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315697] [a_rwnd 6345] [#gap acks 0] [#dup tsns 0]
--> Sudden drop on 1
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315698] [SID: 0] [SSEQ 85] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315698] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Here userspace read, rwnd 'recovered' to 3698, now deplete again using
association 1 so there is place in buffer for only one more packet
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315799] [SID: 0] [SSEQ 186] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315799] [a_rwnd 86] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315800] [SID: 0] [SSEQ 187] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 43] [#gap acks 0] [#dup tsns 0]
--> Socket buffer is almost depleted, but there is space for one more packet,
send them over association 2, size 43B
IP B.12346 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3676403240] [SID: 0] [SSEQ 0] [PPID 0x18]
IP A.55915 > B.12346: sctp (1) [SACK] [cum ack 3676403240] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Immediate drop
IP A.60995 > B.12346: sctp (1) [SACK] [cum ack 387491510] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Read everything from the socket, both association recover up to maximum rwnd
they are capable of reaching, note that association 1 recovered up to 3698,
and association 2 recovered only to 43
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 1548] [#gap acks 0] [#dup tsns 0]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 3053] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315801] [SID: 0] [SSEQ 188] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315801] [a_rwnd 3698] [#gap acks 0] [#dup tsns 0]
IP B.12346 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3676403241] [SID: 0] [SSEQ 1] [PPID 0x18]
IP A.55915 > B.12346: sctp (1) [SACK] [cum ack 3676403241] [a_rwnd 43] [#gap acks 0] [#dup tsns 0]
A careful reader might wonder why it is necessary to reproduce 1) prior
reproduction of 2). It is simply easier to observe when to send packet over
association 2 which will push association into the pressure state.
Proposed solution:
Both problems share the same root cause, and that is improper scaling of socket
buffer with rwnd. Solution in which sizeof(sk_buff) is taken into concern while
calculating rwnd is not possible due to fact that there is no linear
relationship between amount of data blamed in increase/decrease with IP packet
in which payload arrived. Even in case such solution would be followed,
complexity of the code would increase. Due to nature of current rwnd handling,
slow increase (in sctp_assoc_rwnd_increase) of rwnd after pressure state is
entered is rationale, but it gives false representation to the sender of current
buffer space. Furthermore, it implements additional congestion control mechanism
which is defined on implementation, and not on standard basis.
Proposed solution simplifies whole algorithm having on mind definition from rfc:
o Receiver Window (rwnd): This gives the sender an indication of the space
available in the receiver's inbound buffer.
Core of the proposed solution is given with these lines:
sctp_assoc_rwnd_update:
if ((asoc->base.sk->sk_rcvbuf - rx_count) > 0)
asoc->rwnd = (asoc->base.sk->sk_rcvbuf - rx_count) >> 1;
else
asoc->rwnd = 0;
We advertise to sender (half of) actual space we have. Half is in the braces
depending whether you would like to observe size of socket buffer as SO_RECVBUF
or twice the amount, i.e. size is the one visible from userspace, that is,
from kernelspace.
In this way sender is given with good approximation of our buffer space,
regardless of the buffer policy - we always advertise what we have. Proposed
solution fixes described problems and removes necessity for rwnd restoration
algorithm. Finally, as proposed solution is simplification, some lines of code,
along with some bytes in struct sctp_association are saved.
Version 2 of the patch addressed comments from Vlad. Name of the function is set
to be more descriptive, and two parts of code are changed, in one removing the
superfluous call to sctp_assoc_rwnd_update since call would not result in update
of rwnd, and the other being reordering of the code in a way that call to
sctp_assoc_rwnd_update updates rwnd. Version 3 corrected change introduced in v2
in a way that existing function is not reordered/copied in line, but it is
correctly called. Thanks Vlad for suggesting.
Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nsn.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_pf.c
net/ipv6/ip6_tunnel.c
net/ipv6/ip6_vti.c
ipv6 tunnel statistic bug fixes conflicting with consolidation into
generic sw per-cpu net stats.
qlogic conflict between queue counting bug fix and the addition
of multiple MAC address support.
Signed-off-by: David S. Miller <davem@davemloft.net>
The SCTP outqueue structure maintains a data chunks
that are pending transmission, the list of chunks that
are pending a retransmission and a length of data in
flight. It also tries to keep the emtpy state so that
it can performe shutdown sequence or notify user.
The problem is that the empy state is inconsistently
tracked. It is possible to completely drain the queue
without sending anything when using PR-SCTP. In this
case, the empty state will not be correctly state as
report by Jamal Hadi Salim <jhs@mojatatu.com>. This
can cause an association to be perminantly stuck in the
SHUTDOWN_PENDING state.
Additionally, SCTP is incredibly inefficient when setting
the empty state. Even though all the data is availaible
in the outqueue structure, we ignore it and walk a list
of trasnports.
In the end, we can completely remove the extra empty
state and figure out if the queue is empty by looking
at 3 things: length of pending data, length of in-flight
data, and exisiting of retransmit data. All of these
are already in the strucutre.
Reported-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/ethernet/intel/i40e/i40e_main.c
drivers/net/macvtap.c
Both minor merge hassles, simple overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
Members of 'struct association' are not in appropriate order to
reuse compiler added padding on 64bit architectures. In this patch
we reorder those struct members and help reduce the size of the
structure from 2776 bytes to 2720 bytes on 64 bit architectures.
Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, sctp associations latch a sockets autoclose value to an association
at association init time, subject to capping constraints from the max_autoclose
sysctl value. This leads to an odd situation where an application may set a
socket level autoclose timeout, but sliently sctp will limit the autoclose
timeout to something less than that.
Fix this by modifying the autoclose setsockopt function to check the limit, cap
it and warn the user via syslog that the timeout is capped. This will allow
getsockopt to return valid autoclose timeout values that reflect what subsequent
associations actually use.
While were at it, also elimintate the assoc->autoclose variable, it duplicates
whats in the timeout array, which leads to multiple sources for the same
information, that may differ (as the former isn't subject to any capping). This
gives us the timeout information in a canonical place and saves some space in
the association structure as well.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
CC: Wang Weidong <wangweidong1@huawei.com>
CC: David Miller <davem@davemloft.net>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Several files refer to an old address for the Free Software Foundation
in the file header comment. Resolve by replacing the address with
the URL <http://www.gnu.org/licenses/> so that we do not have to keep
updating the header comments anytime the address changes.
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently retransmitted DATA chunks could also be used for
RTT measurements since there are no flag to identify whether
the transmitted DATA chunk is a new one or a retransmitted one.
This problem is introduced by commit ae19c5486 ("sctp: remove
'resent' bit from the chunk") which inappropriately removed the
'resent' bit completely, instead of doing this, we should set
the resent bit only for the retransmitted DATA chunks.
Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reduce cacheline usage from 2 to 1 cacheline for sctp_globals structure. By
reordering elements, we can close gaps and simply achieve the following:
Current situation:
/* size: 80, cachelines: 2, members: 10 */
/* sum members: 57, holes: 4, sum holes: 16 */
/* padding: 7 */
/* last cacheline: 16 bytes */
Afterwards:
/* size: 64, cachelines: 1, members: 10 */
/* padding: 7 */
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the restructuring of the lksctp.org site, we only allow bug
reports through the SCTP mailing list linux-sctp@vger.kernel.org,
not via SF, as SF is only used for web hosting and nothing more.
While at it, also remove the obvious statement that bugs will be
fixed and incooperated into the kernel.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Get rid of the last module parameter for SCTP and make this
configurable via sysctl for SCTP like all the rest of SCTP's
configuration knobs.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When sctp sits on IPv6, sctp_transport_dst_check pass cookie as ZERO,
as a result ip6_dst_check always fail out. This behaviour makes
transport->dst useless, because every sctp_packet_transmit must look
for valid dst.
Add a dst_cookie into sctp_transport, and set the cookie whenever we
get new dst for sctp_transport. So dst validness could be checked
against it.
Since I have split genid for IPv4 and IPv6, also delete/add IPv6 address
will also bump IPv6 genid. So issues we discussed in:
http://marc.info/?l=linux-netdev&m=137404469219410&w=4
have all been sloved for this patch.
Signed-off-by: Fan Du <fan.du@windriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The SCTP mailing list address to send patches or questions
to is linux-sctp@vger.kernel.org and not
lksctp-developers@lists.sourceforge.net anymore. Therefore,
update all occurences.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, SCTP code defines its own timeval functions (since timeval
is rarely used inside the kernel by others), namely tv_lt() and
TIMEVAL_ADD() macros, that operate on SCTP cookie expiration.
We might as well remove all those, and operate directly on ktime
structures for a couple of reasons: ktime is available on all archs;
complexity of ktime calculations depending on the arch is less than
(reduces to a simple arithmetic operations on archs with
BITS_PER_LONG == 64 or CONFIG_KTIME_SCALAR) or equal to timeval
functions (other archs); code becomes more readable; macros can be
thrown out.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
struct sctp_packet is currently embedded into sctp_transport or
sits on the stack as 'singleton' in sctp_outq_flush(). Therefore,
its member 'malloced' is always 0, thus a kfree() is never called.
Because of that, we can just remove this code.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The sctp_bind_addr structure has a 'malloced' member that is
always set to 0, thus in sctp_bind_addr_free() the kfree()
part can never be called. This part is embedded into
sctp_ep_common anyway and never alloced.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_transport's member 'malloced' is set to 1, never evaluated
and the structure is kfreed anyway. So just remove it.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_outq is embedded into sctp_association, and thus never
kmalloced in any way. Also, malloced is always 0, thus kfree()
is never called. Therefore, remove that dead piece of code.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_inq is never kmalloced, since it's integrated into sctp_ep_common
and only initialized from eps and assocs. Therefore, remove the dead
code from there.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_ssnmap_init() can only be called from sctp_ssnmap_new()
where malloced is always set to 1. Thus, when we call
sctp_ssnmap_free() the test for map->malloced evaluates always
to true.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since dead only holds two states (0,1), make it a bool instead
of a 'char', which is more appropriate for its purpose.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is actually no need to keep this member in the structure, because
after init it's always 1 anyway, thus always kfree called. This seems to
be an ancient leftover from the very initial implementation from 2.5
times. Only in case the initialization of an association fails, we leave
base.malloced as 0, but we nevertheless kfree it in the error path in
sctp_association_new().
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Vlad says: The whole multiple cookie keys code is completely unused
and has been all this time. Noone uses anything other then the
secret_key[0] since there is no changeover support anywhere.
Thus, for now clean up its left-over fragments.
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
peer.transport_addr_list is currently only protected by sk_sock
which is inpractical to acquire for procfs dumping purposes.
This patch adds RCU protection allowing for the procfs readers to
enter RCU read-side critical sections.
Modification of the list continues to be serialized via sk_lock.
V2: Use list_del_rcu() in sctp_association_free() to be safe
Skip transports marked dead when dumping for procfs
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The current SCTP stack is lacking a mechanism to have per association
statistics. This is an implementation modeled after OpenSolaris'
SCTP_GET_ASSOC_STATS.
Userspace part will follow on lksctp if/when there is a general ACK on
this.
V4:
- Move ipackets++ before q->immediate.func() for consistency reasons
- Move sctp_max_rto() at the end of sctp_transport_update_rto() to avoid
returning bogus RTO values
- return asoc->rto_min when max_obs_rto value has not changed
V3:
- Increase ictrlchunks in sctp_assoc_bh_rcv() as well
- Move ipackets++ to sctp_inq_push()
- return 0 when no rto updates took place since the last call
V2:
- Implement partial retrieval of stat struct to cope for future expansion
- Kill the rtxpackets counter as it cannot be precise anyway
- Rename outseqtsns to outofseqtsns to make it clearer that these are out
of sequence unexpected TSNs
- Move asoc->ipackets++ under a lock to avoid potential miscounts
- Fold asoc->opackets++ into the already existing asoc check
- Kill unneeded (q->asoc) test when increasing rtxchunks
- Do not count octrlchunks if sending failed (SCTP_XMIT_OK != 0)
- Don't count SHUTDOWNs as SACKs
- Move SCTP_GET_ASSOC_STATS to the private space API
- Adjust the len check in sctp_getsockopt_assoc_stats() to allow for
future struct growth
- Move association statistics in their own struct
- Update idupchunks when we send a SACK with dup TSNs
- return min_rto in max_rto when RTO has not changed. Also return the
transport when max_rto last changed.
Signed-off: Michele Baldessari <michele@acksyn.org>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently sctp allows for the optional use of md5 of sha1 hmac algorithms to
generate cookie values when establishing new connections via two build time
config options. Theres no real reason to make this a static selection. We can
add a sysctl that allows for the dynamic selection of these algorithms at run
time, with the default value determined by the corresponding crypto library
availability.
This comes in handy when, for example running a system in FIPS mode, where use
of md5 is disallowed, but SHA1 is permitted.
Note: This new sysctl has no corresponding socket option to select the cookie
hmac algorithm. I chose not to implement that intentionally, as RFC 6458
contains no option for this value, and I opted not to pollute the socket option
namespace.
Change notes:
v2)
* Updated subject to have the proper sctp prefix as per Dave M.
* Replaced deafult selection options with new options that allow
developers to explicitly select available hmac algs at build time
as per suggestion by Vlad Y.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Suppose we have an SCTP connection with two paths. After connection is
established, path1 is not available, thus this path is marked as inactive. Then
traffic goes through path2, but for some reasons packets are delayed (after
rto.max). Because packets are delayed, the retransmit mechanism will switch
again to path1. At this time, we receive a delayed SACK from path2. When we
update the state of the path in sctp_check_transmitted(), we do not take into
account the source address of the SACK, hence we update the wrong path.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add struct net as a parameter to sctp_verify_param so it can be passed
to sctp_verify_ext_param where struct net will be needed when the sctp
tunables become per net tunables.
Add struct net as a parameter to sctp_verify_init so struct net can be
passed to sctp_verify_param.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
struct net will be needed shortly when the tunables are made per network
namespace.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
- Move the address lists into struct net
- Add per network namespace initialization and cleanup
- Pass around struct net so it is everywhere I need it.
- Rename all of the global variable references into references
to the variables moved into struct net
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
