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2017-06-22rds: tcp: set linger to 1 when unloading a rds-tcpSowmini Varadhan1-0/+1
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>
2017-03-07rds: tcp: Sequence teardown of listen and acceptor sockets to avoid racesSowmini Varadhan1-1/+1
Commit a93d01f5777e ("RDS: TCP: avoid bad page reference in rds_tcp_listen_data_ready") added the function rds_tcp_listen_sock_def_readable() to handle the case when a partially set-up acceptor socket drops into rds_tcp_listen_data_ready(). However, if the listen socket (rtn->rds_tcp_listen_sock) is itself going through a tear-down via rds_tcp_listen_stop(), the (*ready)() will be null and we would hit a panic of the form BUG: unable to handle kernel NULL pointer dereference at (null) IP: (null) : ? rds_tcp_listen_data_ready+0x59/0xb0 [rds_tcp] tcp_data_queue+0x39d/0x5b0 tcp_rcv_established+0x2e5/0x660 tcp_v4_do_rcv+0x122/0x220 tcp_v4_rcv+0x8b7/0x980 : In the above case, it is not fatal to encounter a NULL value for ready- we should just drop the packet and let the flush of the acceptor thread finish gracefully. In general, the tear-down sequence for listen() and accept() socket that is ensured by this commit is: rtn->rds_tcp_listen_sock = NULL; /* prevent any new accepts */ In rds_tcp_listen_stop(): serialize with, and prevent, further callbacks using lock_sock() flush rds_wq flush acceptor workq sock_release(listen socket) Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-15RDS: TCP: avoid bad page reference in rds_tcp_listen_data_readySowmini Varadhan1-0/+1
As the existing comments in rds_tcp_listen_data_ready() indicate, it is possible under some race-windows to get to this function with the accept() socket. If that happens, we could run into a sequence whereby thread 1 thread 2 rds_tcp_accept_one() thread sets up new_sock via ->accept(). The sk_user_data is now sock_def_readable data comes in for new_sock, ->sk_data_ready is called, and we land in rds_tcp_listen_data_ready rds_tcp_set_callbacks() takes the sk_callback_lock and sets up sk_user_data to be the cp read_lock sk_callback_lock ready = cp unlock sk_callback_lock page fault on ready In the above sequence, we end up with a panic on a bad page reference when trying to execute (*ready)(). Instead we need to call sock_def_readable() safely, which is what this patch achieves. 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: Hooks to set up a single connection pathSowmini Varadhan1-2/+2
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 receive path use the rds_conn_pathSowmini Varadhan1-1/+1
The ->sk_user_data contains a pointer to the rds_conn_path for the socket. Use this consistently in the rds_tcp_data_ready callbacks to get the rds_conn_path for rds_recv_incoming. 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 Varadhan1-2/+2
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 Varadhan1-3/+3
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 Varadhan1-3/+3
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>
2016-06-18net: rds: fix coding style issuesJoshua Houghton1-1/+1
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>
2016-06-07RDS: TCP: Add/use rds_tcp_reset_callbacks to reset tcp socket safelySowmini Varadhan1-0/+1
When rds_tcp_accept_one() has to replace the existing tcp socket with a newer tcp socket (duelling-syn resolution), it must lock_sock() to suppress the rds_tcp_data_recv() path while callbacks are being changed. Also, existing RDS datagram reassembly state must be reset, so that the next datagram on the new socket does not have corrupted state. Similarly when resetting the newly accepted socket, appropriate locks and synchronization is needed. This commit ensures correct synchronization by invoking kernel_sock_shutdown to reset a newly accepted sock, and by taking appropriate lock_sock()s (for old and new sockets) when resetting existing callbacks. 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>
2016-05-03RDS: TCP: Synchronize accept() and connect() paths on t_conn_lock.Sowmini Varadhan1-0/+4
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 Varadhan1-2/+5
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>
2014-11-24rds: switch ->inc_copy_to_user() to passing iov_iterAl Viro1-2/+1
instances get considerably simpler from that... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-11net: Fix use after free by removing length arg from sk_data_ready callbacks.David S. Miller1-2/+2
Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-21rds: make local functions/variables staticstephen hemminger1-2/+0
The RDS protocol has lots of functions that should be declared static. rds_message_get/add_version_extension is removed since it defined but never used. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-08RDS: remove __init and __exit annotationZach Brown1-3/+3
The trivial amount of memory saved isn't worth the cost of dealing with section mismatches. Signed-off-by: Zach Brown <zach.brown@oracle.com>
2010-09-08RDS: Stop supporting old cong map sending methodAndy Grover1-2/+0
We now ask the transport to give us a rm for the congestion map, and then we handle it normally. Previously, the transport defined a function that we would call to send a congestion map. Convert TCP and loop transports to new cong map method. Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08RDS: inc_purge() transport function unused - remove itAndy Grover1-1/+0
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2009-08-23RDS: Add TCP transport to RDSAndy Grover1-0/+93
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>