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2018-08-08rxrpc: Fix the keepalive generator [ver #2]David Howells
AF_RXRPC has a keepalive message generator that generates a message for a peer ~20s after the last transmission to that peer to keep firewall ports open. The implementation is incorrect in the following ways: (1) It mixes up ktime_t and time64_t types. (2) It uses ktime_get_real(), the output of which may jump forward or backward due to adjustments to the time of day. (3) If the current time jumps forward too much or jumps backwards, the generator function will crank the base of the time ring round one slot at a time (ie. a 1s period) until it catches up, spewing out VERSION packets as it goes. Fix the problem by: (1) Only using time64_t. There's no need for sub-second resolution. (2) Use ktime_get_seconds() rather than ktime_get_real() so that time isn't perceived to go backwards. (3) Simplifying rxrpc_peer_keepalive_worker() by splitting it into two parts: (a) The "worker" function that manages the buckets and the timer. (b) The "dispatch" function that takes the pending peers and potentially transmits a keepalive packet before putting them back in the ring into the slot appropriate to the revised last-Tx time. (4) Taking everything that's pending out of the ring and splicing it into a temporary collector list for processing. In the case that there's been a significant jump forward, the ring gets entirely emptied and then the time base can be warped forward before the peers are processed. The warping can't happen if the ring isn't empty because the slot a peer is in is keepalive-time dependent, relative to the base time. (5) Limit the number of iterations of the bucket array when scanning it. (6) Set the timer to skip any empty slots as there's no point waking up if there's nothing to do yet. This can be triggered by an incoming call from a server after a reboot with AF_RXRPC and AFS built into the kernel causing a peer record to be set up before userspace is started. The system clock is then adjusted by userspace, thereby potentially causing the keepalive generator to have a meltdown - which leads to a message like: watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:23] ... Workqueue: krxrpcd rxrpc_peer_keepalive_worker EIP: lock_acquire+0x69/0x80 ... Call Trace: ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? _raw_spin_lock_bh+0x29/0x60 ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? __lock_acquire+0x3d3/0x870 ? process_one_work+0x110/0x340 ? process_one_work+0x166/0x340 ? process_one_work+0x110/0x340 ? worker_thread+0x39/0x3c0 ? kthread+0xdb/0x110 ? cancel_delayed_work+0x90/0x90 ? kthread_stop+0x70/0x70 ? ret_from_fork+0x19/0x24 Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-30rxrpc: Fix leak of rxrpc_peer objectsDavid Howells
When a new client call is requested, an rxrpc_conn_parameters struct object is passed in with a bunch of parameters set, such as the local endpoint to use. A pointer to the target peer record is also placed in there by rxrpc_get_client_conn() - and this is removed if and only if a new connection object is allocated. Thus it leaks if a new connection object isn't allocated. Fix this by putting any peer object attached to the rxrpc_conn_parameters object in the function that allocated it. Fixes: 19ffa01c9c45 ("rxrpc: Use structs to hold connection params and protocol info") Signed-off-by: David Howells <dhowells@redhat.com>
2018-03-30rxrpc: Add a tracepoint to track rxrpc_peer refcountingDavid Howells
Add a tracepoint to track reference counting on the rxrpc_peer struct. Signed-off-by: David Howells <dhowells@redhat.com>
2018-03-30rxrpc: Fix firewall route keepaliveDavid Howells
Fix the firewall route keepalive part of AF_RXRPC which is currently function incorrectly by replying to VERSION REPLY packets from the server with VERSION REQUEST packets. Instead, send VERSION REPLY packets to the peers of service connections to act as keep-alives 20s after the latest packet was transmitted to that peer. Also, just discard VERSION REPLY packets rather than replying to them. Signed-off-by: David Howells <dhowells@redhat.com>
2017-10-18rxrpc: Provide functions for allowing cleaner handling of signalsDavid Howells
Provide a couple of functions to allow cleaner handling of signals in a kernel service. They are: (1) rxrpc_kernel_get_rtt() This allows the kernel service to find out the RTT time for a call, so as to better judge how large a timeout to employ. Note, though, that whilst this returns a value in nanoseconds, the timeouts can only actually be in jiffies. (2) rxrpc_kernel_check_life() This returns a number that is updated when ACKs are received from the peer (notably including PING RESPONSE ACKs which we can elicit by sending PING ACKs to see if the call still exists on the server). The caller should compare the numbers of two calls to see if the call is still alive. These can be used to provide an extending timeout rather than returning immediately in the case that a signal occurs that would otherwise abort an RPC operation. The timeout would be extended if the server is still responsive and the call is still apparently alive on the server. For most operations this isn't that necessary - but for FS.StoreData it is: OpenAFS writes the data to storage as it comes in without making a backup, so if we immediately abort it when partially complete on a CTRL+C, say, we have no idea of the state of the file after the abort. Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-14rxrpc: Cache the congestion window settingDavid Howells
Cache the congestion window setting that was determined during a call's transmission phase when it finishes so that it can be used by the next call to the same peer, thereby shortcutting the slow-start algorithm. The value is stored in the rxrpc_peer struct and is accessed without locking. Each call takes the value that happens to be there when it starts and just overwrites the value when it finishes. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-25rxrpc: Support network namespacingDavid Howells
Support network namespacing in AF_RXRPC with the following changes: (1) All the local endpoint, peer and call lists, locks, counters, etc. are moved into the per-namespace record. (2) All the connection tracking is moved into the per-namespace record with the exception of the client connection ID tree, which is kept global so that connection IDs are kept unique per-machine. (3) Each namespace gets its own epoch. This allows each network namespace to pretend to be a separate client machine. (4) The /proc/net/rxrpc_xxx files are now called /proc/net/rxrpc/xxx and the contents reflect the namespace. fs/afs/ should be okay with this patch as it explicitly requires the current net namespace to be init_net to permit a mount to proceed at the moment. It will, however, need updating so that cells, IP addresses and DNS records are per-namespace also. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13rxrpc: Fix checking of error from ip6_route_output()David Howells
ip6_route_output() doesn't return a negative error when it fails, rather the ->error field of the returned dst_entry struct needs to be checked. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: 75b54cb57ca3 ("rxrpc: Add IPv6 support") Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-22rxrpc: Reduce the number of ACK-Requests sentDavid Howells
Reduce the number of ACK-Requests we set on DATA packets that we're sending to reduce network traffic. We set the flag on odd-numbered DATA packets to start off the RTT cache until we have at least three entries in it and then probe once per second thereafter to keep it topped up. This could be made tunable in future. Note that from this point, the RXRPC_REQUEST_ACK flag is set on DATA packets as we transmit them and not stored statically in the sk_buff. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-17rxrpc: Make IPv6 support conditional on CONFIG_IPV6David Howells
Add CONFIG_AF_RXRPC_IPV6 and make the IPv6 support code conditional on it. This is then made conditional on CONFIG_IPV6. Without this, the following can be seen: net/built-in.o: In function `rxrpc_init_peer': >> peer_object.c:(.text+0x18c3c8): undefined reference to `ip6_route_output_flags' Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-13rxrpc: Add IPv6 supportDavid Howells
Add IPv6 support to AF_RXRPC. With this, AF_RXRPC sockets can be created: service = socket(AF_RXRPC, SOCK_DGRAM, PF_INET6); instead of: service = socket(AF_RXRPC, SOCK_DGRAM, PF_INET); The AFS filesystem doesn't support IPv6 at the moment, though, since that requires upgrades to some of the RPC calls. Note that a good portion of this patch is replacing "%pI4:%u" in print statements with "%pISpc" which is able to handle both protocols and print the port. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-13rxrpc: Make sure we initialise the peer hash keyDavid Howells
Peer records created for incoming connections weren't getting their hash key set. This meant that incoming calls wouldn't see more than one DATA packet - which is not a problem for AFS CM calls with small request data blobs. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-08rxrpc: Rewrite the data and ack handling codeDavid Howells
Rewrite the data and ack handling code such that: (1) Parsing of received ACK and ABORT packets and the distribution and the filing of DATA packets happens entirely within the data_ready context called from the UDP socket. This allows us to process and discard ACK and ABORT packets much more quickly (they're no longer stashed on a queue for a background thread to process). (2) We avoid calling skb_clone(), pskb_pull() and pskb_trim(). We instead keep track of the offset and length of the content of each packet in the sk_buff metadata. This means we don't do any allocation in the receive path. (3) Jumbo DATA packet parsing is now done in data_ready context. Rather than cloning the packet once for each subpacket and pulling/trimming it, we file the packet multiple times with an annotation for each indicating which subpacket is there. From that we can directly calculate the offset and length. (4) A call's receive queue can be accessed without taking locks (memory barriers do have to be used, though). (5) Incoming calls are set up from preallocated resources and immediately made live. They can than have packets queued upon them and ACKs generated. If insufficient resources exist, DATA packet #1 is given a BUSY reply and other DATA packets are discarded). (6) sk_buffs no longer take a ref on their parent call. To make this work, the following changes are made: (1) Each call's receive buffer is now a circular buffer of sk_buff pointers (rxtx_buffer) rather than a number of sk_buff_heads spread between the call and the socket. This permits each sk_buff to be in the buffer multiple times. The receive buffer is reused for the transmit buffer. (2) A circular buffer of annotations (rxtx_annotations) is kept parallel to the data buffer. Transmission phase annotations indicate whether a buffered packet has been ACK'd or not and whether it needs retransmission. Receive phase annotations indicate whether a slot holds a whole packet or a jumbo subpacket and, if the latter, which subpacket. They also note whether the packet has been decrypted in place. (3) DATA packet window tracking is much simplified. Each phase has just two numbers representing the window (rx_hard_ack/rx_top and tx_hard_ack/tx_top). The hard_ack number is the sequence number before base of the window, representing the last packet the other side says it has consumed. hard_ack starts from 0 and the first packet is sequence number 1. The top number is the sequence number of the highest-numbered packet residing in the buffer. Packets between hard_ack+1 and top are soft-ACK'd to indicate they've been received, but not yet consumed. Four macros, before(), before_eq(), after() and after_eq() are added to compare sequence numbers within the window. This allows for the top of the window to wrap when the hard-ack sequence number gets close to the limit. Two flags, RXRPC_CALL_RX_LAST and RXRPC_CALL_TX_LAST, are added also to indicate when rx_top and tx_top point at the packets with the LAST_PACKET bit set, indicating the end of the phase. (4) Calls are queued on the socket 'receive queue' rather than packets. This means that we don't need have to invent dummy packets to queue to indicate abnormal/terminal states and we don't have to keep metadata packets (such as ABORTs) around (5) The offset and length of a (sub)packet's content are now passed to the verify_packet security op. This is currently expected to decrypt the packet in place and validate it. However, there's now nowhere to store the revised offset and length of the actual data within the decrypted blob (there may be a header and padding to skip) because an sk_buff may represent multiple packets, so a locate_data security op is added to retrieve these details from the sk_buff content when needed. (6) recvmsg() now has to handle jumbo subpackets, where each subpacket is individually secured and needs to be individually decrypted. The code to do this is broken out into rxrpc_recvmsg_data() and shared with the kernel API. It now iterates over the call's receive buffer rather than walking the socket receive queue. Additional changes: (1) The timers are condensed to a single timer that is set for the soonest of three timeouts (delayed ACK generation, DATA retransmission and call lifespan). (2) Transmission of ACK and ABORT packets is effected immediately from process-context socket ops/kernel API calls that cause them instead of them being punted off to a background work item. The data_ready handler still has to defer to the background, though. (3) A shutdown op is added to the AF_RXRPC socket so that the AFS filesystem can shut down the socket and flush its own work items before closing the socket to deal with any in-progress service calls. Future additional changes that will need to be considered: (1) Make sure that a call doesn't hog the front of the queue by receiving data from the network as fast as userspace is consuming it to the exclusion of other calls. (2) Transmit delayed ACKs from within recvmsg() when we've consumed sufficiently more packets to avoid the background work item needing to run. Signed-off-by: David Howells <dhowells@redhat.com>
2016-08-30rxrpc: Provide a way for AFS to ask for the peer address of a callDavid Howells
Provide a function so that kernel users, such as AFS, can ask for the peer address of a call: void rxrpc_kernel_get_peer(struct rxrpc_call *call, struct sockaddr_rxrpc *_srx); In the future the kernel service won't get sk_buffs to look inside. Further, this allows us to hide any canonicalisation inside AF_RXRPC for when IPv6 support is added. Also propagate this through to afs_find_server() and issue a warning if we can't handle the address family yet. Signed-off-by: David Howells <dhowells@redhat.com>
2016-07-06rxrpc: Use RCU to access a peer's service connection treeDavid Howells
Move to using RCU access to a peer's service connection tree when routing an incoming packet. This is done using a seqlock to trigger retrying of the tree walk if a change happened. Further, we no longer get a ref on the connection looked up in the data_ready handler unless we queue the connection's work item - and then only if the refcount > 0. Note that I'm avoiding the use of a hash table for service connections because each service connection is addressed by a 62-bit number (constructed from epoch and connection ID >> 2) that would allow the client to engage in bucket stuffing, given knowledge of the hash algorithm. Peers, however, are hashed as the network address is less controllable by the client. The total number of peers will also be limited in a future commit. Signed-off-by: David Howells <dhowells@redhat.com>
2016-06-22rxrpc: Kill off the rxrpc_transport structDavid Howells
The rxrpc_transport struct is now redundant, given that the rxrpc_peer struct is now per peer port rather than per peer host, so get rid of it. Service connection lists are transferred to the rxrpc_peer struct, as is the conn_lock. Previous patches moved the client connection handling out of the rxrpc_transport struct and discarded the connection bundling code. Signed-off-by: David Howells <dhowells@redhat.com>
2016-06-22rxrpc: fix uninitialized variable useArnd Bergmann
Hashing the peer key was introduced for AF_INET, but gcc warns about the rxrpc_peer_hash_key function returning uninitialized data for any other value of srx->transport.family: net/rxrpc/peer_object.c: In function 'rxrpc_peer_hash_key': net/rxrpc/peer_object.c:57:15: error: 'p' may be used uninitialized in this function [-Werror=maybe-uninitialized] Assuming that nothing else can be set here, this changes the function to just return zero in case of an unknown address family. Fixes: be6e6707f6ee ("rxrpc: Rework peer object handling to use hash table and RCU") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David Howells <dhowells@redhat.com>
2016-06-15rxrpc: Use the peer record to distribute network errorsDavid Howells
Use the peer record to distribute network errors rather than the transport object (which I want to get rid of). An error from a particular peer terminates all calls on that peer. For future consideration: (1) For ICMP-induced errors it might be worth trying to extract the RxRPC header from the offending packet, if one is returned attached to the ICMP packet, to better direct the error. This may be overkill, though, since an ICMP packet would be expected to be relating to the destination port, machine or network. RxRPC ABORT and BUSY packets give notice at RxRPC level. (2) To also abort connection-level communications (such as CHALLENGE packets) where indicted by an error - but that requires some revamping of the connection event handling first. Signed-off-by: David Howells <dhowells@redhat.com>
2016-06-15rxrpc: Rework peer object handling to use hash table and RCUDavid Howells
Rework peer object handling to use a hash table instead of a flat list and to use RCU. Peer objects are no longer destroyed by passing them to a workqueue to process, but rather are just passed to the RCU garbage collector as kfree'able objects. The hash function uses the local endpoint plus all the components of the remote address, except for the RxRPC service ID. Peers thus represent a UDP port on the remote machine as contacted by a UDP port on this machine. The RCU read lock is used to handle non-creating lookups so that they can be called from bottom half context in the sk_error_report handler without having to lock the hash table against modification. rxrpc_lookup_peer_rcu() *does* take a reference on the peer object as in the future, this will be passed to a work item for error distribution in the error_report path and this function will cease being used in the data_ready path. Creating lookups are done under spinlock rather than mutex as they might be set up due to an external stimulus if the local endpoint is a server. Captured network error messages (ICMP) are handled with respect to this struct and MTU size and RTT are cached here. Signed-off-by: David Howells <dhowells@redhat.com>
2016-06-13rxrpc: Rename files matching ar-*.c to git rid of the "ar-" prefixDavid Howells
Rename files matching net/rxrpc/ar-*.c to get rid of the "ar-" prefix. This will aid splitting those files by making easier to come up with new names. Note that the not all files are simply renamed from ar-X.c to X.c. The following exceptions are made: (*) ar-call.c -> call_object.c ar-ack.c -> call_event.c call_object.c is going to contain the core of the call object handling. Call event handling is all going to be in call_event.c. (*) ar-accept.c -> call_accept.c Incoming call handling is going to be here. (*) ar-connection.c -> conn_object.c ar-connevent.c -> conn_event.c The former file is going to have the basic connection object handling, but there will likely be some differentiation between client connections and service connections in additional files later. The latter file will have all the connection-level event handling. (*) ar-local.c -> local_object.c This will have the local endpoint object handling code. The local endpoint event handling code will later be split out into local_event.c. (*) ar-peer.c -> peer_object.c This will have the peer endpoint object handling code. Peer event handling code will be placed in peer_event.c (for the moment, there is none). (*) ar-error.c -> peer_event.c This will become the peer event handling code, though for the moment it's actually driven from the local endpoint's perspective. Note that I haven't renamed ar-transport.c to transport_object.c as the intention is to delete it when the rxrpc_transport struct is excised. The only file that actually has its contents changed is net/rxrpc/Makefile. net/rxrpc/ar-internal.h will need its section marker comments updating, but I'll do that in a separate patch to make it easier for git to follow the history across the rename. I may also want to rename ar-internal.h at some point - but that would mean updating all the #includes and I'd rather do that in a separate step. Signed-off-by: David Howells <dhowells@redhat.com.