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path: root/net/rds/tcp_connect.c
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2017-07-16rds: cancel send/recv work before queuing connection shutdownSowmini Varadhan
We could end up executing rds_conn_shutdown before the rds_recv_worker thread, then rds_conn_shutdown -> rds_tcp_conn_shutdown can do a sock_release and set sock->sk to null, which may interleave in bad ways with rds_recv_worker, e.g., it could result in: "BUG: unable to handle kernel NULL pointer dereference at 0000000000000078" [ffff881769f6fd70] release_sock at ffffffff815f337b [ffff881769f6fd90] rds_tcp_recv at ffffffffa043c888 [rds_tcp] [ffff881769f6fdb0] rds_recv_worker at ffffffffa04a4810 [rds] [ffff881769f6fde0] process_one_work at ffffffff810a14c1 [ffff881769f6fe40] worker_thread at ffffffff810a1940 [ffff881769f6fec0] kthread at ffffffff810a6b1e Also, do not enqueue any new shutdown workq items when the connection is shutting down (this may happen for rds-tcp in softirq mode, if a FIN or CLOSE is received while the modules is in the middle of an unload) Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-22rds: tcp: set linger to 1 when unloading a rds-tcpSowmini Varadhan
If we are unloading the rds_tcp module, we can set linger to 1 and drop pending packets to accelerate reconnect. The peer will end up resetting the connection based on new generation numbers of the new incarnation, so hanging on to unsent TCP packets via linger is mostly pointless in this case. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Tested-by: Jenny Xu <jenny.x.xu@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-16rds: tcp: various endian-ness fixesSowmini Varadhan
Found when testing between sparc and x86 machines on different subnets, so the address comparison patterns hit the corner cases and brought out some bugs fixed by this patch. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Tested-by: Imanti Mendez <imanti.mendez@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-16rds: tcp: remove cp_outgoingSowmini Varadhan
After commit 1a0e100fb2c9 ("RDS: TCP: Force every connection to be initiated by numerically smaller IP address") we no longer need the logic associated with cp_outgoing, so clean up usage of this field. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Tested-by: Imanti Mendez <imanti.mendez@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-17RDS: TCP: Force every connection to be initiated by numerically smaller IP ↵Sowmini Varadhan
address When 2 RDS peers initiate an RDS-TCP connection simultaneously, there is a potential for "duelling syns" on either/both sides. See commit 241b271952eb ("RDS-TCP: Reset tcp callbacks if re-using an outgoing socket in rds_tcp_accept_one()") for a description of this condition, and the arbitration logic which ensures that the numerically large IP address in the TCP connection is bound to the RDS_TCP_PORT ("canonical ordering"). The rds_connection should not be marked as RDS_CONN_UP until the arbitration logic has converged for the following reason. The sender may start transmitting RDS datagrams as soon as RDS_CONN_UP is set, and since the sender removes all datagrams from the rds_connection's cp_retrans queue based on TCP acks. If the TCP ack was sent from a tcp socket that got reset as part of duel aribitration (but before data was delivered to the receivers RDS socket layer), the sender may end up prematurely freeing the datagram, and the datagram is no longer reliably deliverable. This patch remedies that condition by making sure that, upon receipt of 3WH completion state change notification of TCP_ESTABLISHED in rds_tcp_state_change, we mark the rds_connection as RDS_CONN_UP if, and only if, the IP addresses and ports for the connection are canonically ordered. In all other cases, rds_tcp_state_change will force an rds_conn_path_drop(), and rds_queue_reconnect() on both peers will restart the connection to ensure canonical ordering. A side-effect of enforcing this condition in rds_tcp_state_change() is that rds_tcp_accept_one_path() can now be refactored for simplicity. It is also no longer possible to encounter an RDS_CONN_UP connection in the arbitration logic in rds_tcp_accept_one(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-15RDS: TCP: Enable multipath RDS for TCPSowmini Varadhan
Use RDS probe-ping to compute how many paths may be used with the peer, and to synchronously start the multiple paths. If mprds is supported, hash outgoing traffic to one of multiple paths in rds_sendmsg() when multipath RDS is supported by the transport. CC: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01RDS: TCP: Hooks to set up a single connection pathSowmini Varadhan
This patch adds ->conn_path_connect callbacks in the rds_transport that are used to set up a single connection path. Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01RDS: TCP: make ->sk_user_data point to a rds_conn_pathSowmini Varadhan
The socket callbacks should all operate on a struct rds_conn_path, in preparation for a MP capable RDS-TCP. Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01RDS: TCP: Make rds_tcp_connection track the rds_conn_pathSowmini Varadhan
The struct rds_tcp_connection is the transport-specific private data structure that tracks TCP information per rds_conn_path. Modify this structure to have a back-pointer to the rds_conn_path for which it is the ->cp_transport_data. Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01RDS: Rework path specific indirectionsSowmini Varadhan
Refactor code to avoid separate indirections for single-path and multipath transports. All transports (both single and mp-capable) will get a pointer to the rds_conn_path, and can trivially derive the rds_connection from the ->cp_conn. Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Several cases of overlapping changes, except the packet scheduler conflicts which deal with the addition of the free list parameter to qdisc_enqueue(). Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-18net: rds: fix coding style issuesJoshua Houghton
Fix coding style issues in the following files: ib_cm.c: add space loop.c: convert spaces to tabs sysctl.c: add space tcp.h: convert spaces to tabs tcp_connect.c:remove extra indentation in switch statement tcp_recv.c: convert spaces to tabs tcp_send.c: convert spaces to tabs transport.c: move brace up one line on for statement Signed-off-by: Joshua Houghton <josh@awful.name> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-14RDS: split out connection specific state from rds_connection to rds_conn_pathSowmini Varadhan
In preparation for multipath RDS, split the rds_connection structure into a base structure, and a per-path struct rds_conn_path. The base structure tracks information and locks common to all paths. The workqs for send/recv/shutdown etc are tracked per rds_conn_path. Thus the workq callbacks now work with rds_conn_path. This commit allows for one rds_conn_path per rds_connection, and will be extended into multiple conn_paths in subsequent commits. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-07RDS: TCP: fix race windows in send-path quiescence by rds_tcp_accept_one()Sowmini Varadhan
The send path needs to be quiesced before resetting callbacks from rds_tcp_accept_one(), and commit eb192840266f ("RDS:TCP: Synchronize rds_tcp_accept_one with rds_send_xmit when resetting t_sock") achieves this using the c_state and RDS_IN_XMIT bit following the pattern used by rds_conn_shutdown(). However this leaves the possibility of a race window as shown in the sequence below take t_conn_lock in rds_tcp_conn_connect send outgoing syn to peer drop t_conn_lock in rds_tcp_conn_connect incoming from peer triggers rds_tcp_accept_one, conn is marked CONNECTING wait for RDS_IN_XMIT to quiesce any rds_send_xmit threads call rds_tcp_reset_callbacks [.. race-window where incoming syn-ack can cause the conn to be marked UP from rds_tcp_state_change ..] lock_sock called from rds_tcp_reset_callbacks, and we set t_sock to null As soon as the conn is marked UP in the race-window above, rds_send_xmit() threads will proceed to rds_tcp_xmit and may encounter a null-pointer deref on the t_sock. Given that rds_tcp_state_change() is invoked in softirq context, whereas rds_tcp_reset_callbacks() is in workq context, and testing for RDS_IN_XMIT after lock_sock could result in a deadlock with tcp_sendmsg, this commit fixes the race by using a new c_state, RDS_TCP_RESETTING, which will prevent a transition to RDS_CONN_UP from rds_tcp_state_change(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-19rds: tcp: block BH in TCP callbacksEric Dumazet
TCP stack can now run from process context. Use read_lock_bh(&sk->sk_callback_lock) variant to restore previous assumption. Fixes: 5413d1babe8f ("net: do not block BH while processing socket backlog") Fixes: d41a69f1d390 ("tcp: make tcp_sendmsg() aware of socket backlog") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-03RDS: TCP: Synchronize accept() and connect() paths on t_conn_lock.Sowmini Varadhan
An arbitration scheme for duelling SYNs is implemented as part of commit 241b271952eb ("RDS-TCP: Reset tcp callbacks if re-using an outgoing socket in rds_tcp_accept_one()") which ensures that both nodes involved will arrive at the same arbitration decision. However, this needs to be synchronized with an outgoing SYN to be generated by rds_tcp_conn_connect(). This commit achieves the synchronization through the t_conn_lock mutex in struct rds_tcp_connection. The rds_conn_state is checked in rds_tcp_conn_connect() after acquiring the t_conn_lock mutex. A SYN is sent out only if the RDS connection is not already UP (an UP would indicate that rds_tcp_accept_one() has completed 3WH, so no SYN needs to be generated). Similarly, the rds_conn_state is checked in rds_tcp_accept_one() after acquiring the t_conn_lock mutex. The only acceptable states (to allow continuation of the arbitration logic) are UP (i.e., outgoing SYN was SYN-ACKed by peer after it sent us the SYN) or CONNECTING (we sent outgoing SYN before we saw incoming SYN). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-07RDS-TCP: Support multiple RDS-TCP listen endpoints, one per netns.Sowmini Varadhan
Register pernet subsys init/stop functions that will set up and tear down per-net RDS-TCP listen endpoints. Unregister pernet subusys functions on 'modprobe -r' to clean up these end points. Enable keepalive on both accept and connect socket endpoints. The keepalive timer expiration will ensure that client socket endpoints will be removed as appropriate from the netns when an interface is removed from a namespace. Register a device notifier callback that will clean up all sockets (and thus avoid the need to wait for keepalive timeout) when the loopback device is unregistered from the netns indicating that the netns is getting deleted. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-07RDS-TCP: Make RDS-TCP work correctly when it is set up in a netns other than ↵Sowmini Varadhan
init_net Open the sockets calling sock_create_kern() with the correct struct net pointer, and use that struct net pointer when verifying the address passed to rds_bind(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-09net/rds: RDS-TCP: Always create a new rds_sock for an incoming connection.Sowmini Varadhan
When running RDS over TCP, the active (client) side connects to the listening ("passive") side at the RDS_TCP_PORT. After the connection is established, if the client side reboots (potentially without even sending a FIN) the server still has a TCP socket in the esablished state. If the server-side now gets a new SYN comes from the client with a different client port, TCP will create a new socket-pair, but the RDS layer will incorrectly pull up the old rds_connection (which is still associated with the stale t_sock and RDS socket state). This patch corrects this behavior by having rds_tcp_accept_one() always create a new connection for an incoming TCP SYN. The rds and tcp state associated with the old socket-pair is cleaned up via the rds_tcp_state_change() callback which would typically be invoked in most cases when the client-TCP sends a FIN on TCP restart, triggering a transition to CLOSE_WAIT state. In the rarer event of client death without a FIN, TCP_KEEPALIVE probes on the socket will detect the stale socket, and the TCP transition to CLOSE state will trigger the RDS state cleanup. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-03net/rds: do proper house keeping if connection fails in rds_tcp_conn_connectHerton R. Krzesinski
I see two problems if we consider the sock->ops->connect attempt to fail in rds_tcp_conn_connect. The first issue is that for example we don't remove the previously added rds_tcp_connection item to rds_tcp_tc_list at rds_tcp_set_callbacks, which means that on a next reconnect attempt for the same rds_connection, when rds_tcp_conn_connect is called we can again call rds_tcp_set_callbacks, resulting in duplicated items on rds_tcp_tc_list, leading to list corruption: to avoid this just make sure we call properly rds_tcp_restore_callbacks before we exit. The second issue is that we should also release the sock properly, by setting sock = NULL only if we are returning without error. Signed-off-by: Herton R. Krzesinski <herton@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-22rds: Don't disable BH on BH contextYing Xue
Since we have already in BH context when *_write_space(), *_data_ready() as well as *_state_change() are called, it's unnecessary to disable BH. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-27Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/qlcnic/qlcnic_init.c net/ipv4/ip_output.c
2010-09-24net: fix a lockdep splatEric Dumazet
We have for each socket : One spinlock (sk_slock.slock) One rwlock (sk_callback_lock) Possible scenarios are : (A) (this is used in net/sunrpc/xprtsock.c) read_lock(&sk->sk_callback_lock) (without blocking BH) <BH> spin_lock(&sk->sk_slock.slock); ... read_lock(&sk->sk_callback_lock); ... (B) write_lock_bh(&sk->sk_callback_lock) stuff write_unlock_bh(&sk->sk_callback_lock) (C) spin_lock_bh(&sk->sk_slock) ... write_lock_bh(&sk->sk_callback_lock) stuff write_unlock_bh(&sk->sk_callback_lock) spin_unlock_bh(&sk->sk_slock) This (C) case conflicts with (A) : CPU1 [A] CPU2 [C] read_lock(callback_lock) <BH> spin_lock_bh(slock) <wait to spin_lock(slock)> <wait to write_lock_bh(callback_lock)> We have one problematic (C) use case in inet_csk_listen_stop() : local_bh_disable(); bh_lock_sock(child); // spin_lock_bh(&sk->sk_slock) WARN_ON(sock_owned_by_user(child)); ... sock_orphan(child); // write_lock_bh(&sk->sk_callback_lock) lockdep is not happy with this, as reported by Tetsuo Handa It seems only way to deal with this is to use read_lock_bh(callbacklock) everywhere. Thanks to Jarek for pointing a bug in my first attempt and suggesting this solution. Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Jarek Poplawski <jarkao2@gmail.com> Tested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-08RDS: cleanup: remove "== NULL"s and "!= NULL"s in ptr comparisonsAndy Grover
Favor "if (foo)" style over "if (foo != NULL)". Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-05-17net: Remove unnecessary semicolons after switch statementsJoe Perches
Also added an explicit break; to avoid a fallthrough in net/ipv4/tcp_input.c Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-02-03net/rds: remove uses of NIPQUAD, use %pI4Joe Perches
Signed-off-by: Joe Perches <joe@perches.com> Cc: Andy Grover <andy.grover@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-08-23RDS: Add TCP transport to RDSAndy Grover
This code allows RDS to be tunneled over a TCP connection. RDMA operations are disabled when using TCP transport, but this frees RDS from the IB/RDMA stack dependency, and allows it to be used with standard Ethernet adapters, or in a VM. Signed-off-by: Andy Grover <andy.grover@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>