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rxrpc: Perform terminal call ACK/ABORT retransmission from conn processor

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Perform terminal call ACK/ABORT retransmission in the connection processor
rather than in the call processor.  With this change, once last_call is
set, no more incoming packets will be routed to the corresponding call or
any earlier calls on that channel (call IDs must only increase on a channel
on a connection).

Further, if a packet's callNumber is before the last_call ID or a packet is
aimed at successfully completed service call then that packet is discarded
and ignored.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2016-08-23 15:27:25 +01:00
parent 563ea7d5d4
commit 18bfeba50d
4 changed files with 157 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
net/rxrpc/ar-internal.h
View File

@ -295,7 +295,12 @@ struct rxrpc_connection {
u32 call_id; /* ID of current call */
u32 call_counter; /* Call ID counter */
u32 last_call; /* ID of last call */
u32 last_result; /* Result of last call (0/abort) */
u8 last_type; /* Type of last packet */
u16 last_service_id;
union {
u32 last_seq;
u32 last_abort;
};
} channels[RXRPC_MAXCALLS];
wait_queue_head_t channel_wq; /* queue to wait for channel to become available */

113
net/rxrpc/conn_event.c
View File

@ -24,6 +24,113 @@
#include <net/ip.h>
#include "ar-internal.h"
/*
* Retransmit terminal ACK or ABORT of the previous call.
*/
static void rxrpc_conn_retransmit(struct rxrpc_connection *conn,
struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct rxrpc_channel *chan;
struct msghdr msg;
struct kvec iov;
struct {
struct rxrpc_wire_header whdr;
union {
struct {
__be32 code;
} abort;
struct {
struct rxrpc_ackpacket ack;
struct rxrpc_ackinfo info;
};
};
} __attribute__((packed)) pkt;
size_t len;
u32 serial, mtu, call_id;
_enter("%d", conn->debug_id);
chan = &conn->channels[sp->hdr.cid & RXRPC_CHANNELMASK];
/* If the last call got moved on whilst we were waiting to run, just
* ignore this packet.
*/
call_id = READ_ONCE(chan->last_call);
/* Sync with __rxrpc_disconnect_call() */
smp_rmb();
if (call_id != sp->hdr.callNumber)
return;
msg.msg_name = &conn->params.peer->srx.transport;
msg.msg_namelen = conn->params.peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
pkt.whdr.epoch = htonl(sp->hdr.epoch);
pkt.whdr.cid = htonl(sp->hdr.cid);
pkt.whdr.callNumber = htonl(sp->hdr.callNumber);
pkt.whdr.seq = 0;
pkt.whdr.type = chan->last_type;
pkt.whdr.flags = conn->out_clientflag;
pkt.whdr.userStatus = 0;
pkt.whdr.securityIndex = conn->security_ix;
pkt.whdr._rsvd = 0;
pkt.whdr.serviceId = htons(chan->last_service_id);
len = sizeof(pkt.whdr);
switch (chan->last_type) {
case RXRPC_PACKET_TYPE_ABORT:
pkt.abort.code = htonl(chan->last_abort);
len += sizeof(pkt.abort);
break;
case RXRPC_PACKET_TYPE_ACK:
mtu = conn->params.peer->if_mtu;
mtu -= conn->params.peer->hdrsize;
pkt.ack.bufferSpace = 0;
pkt.ack.maxSkew = htons(skb->priority);
pkt.ack.firstPacket = htonl(chan->last_seq);
pkt.ack.previousPacket = htonl(chan->last_seq - 1);
pkt.ack.serial = htonl(sp->hdr.serial);
pkt.ack.reason = RXRPC_ACK_DUPLICATE;
pkt.ack.nAcks = 0;
pkt.info.rxMTU = htonl(rxrpc_rx_mtu);
pkt.info.maxMTU = htonl(mtu);
pkt.info.rwind = htonl(rxrpc_rx_window_size);
pkt.info.jumbo_max = htonl(rxrpc_rx_jumbo_max);
len += sizeof(pkt.ack) + sizeof(pkt.info);
break;
}
/* Resync with __rxrpc_disconnect_call() and check that the last call
* didn't get advanced whilst we were filling out the packets.
*/
smp_rmb();
if (READ_ONCE(chan->last_call) != call_id)
return;
iov.iov_base = &pkt;
iov.iov_len = len;
serial = atomic_inc_return(&conn->serial);
pkt.whdr.serial = htonl(serial);
switch (chan->last_type) {
case RXRPC_PACKET_TYPE_ABORT:
_proto("Tx ABORT %%%u { %d } [re]", serial, conn->local_abort);
break;
case RXRPC_PACKET_TYPE_ACK:
_proto("Tx ACK %%%u [re]", serial);
break;
}
kernel_sendmsg(conn->params.local->socket, &msg, &iov, 1, len);
_leave("");
return;
}
/*
* pass a connection-level abort onto all calls on that connection
*/
@ -166,6 +273,12 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
_enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
switch (sp->hdr.type) {
case RXRPC_PACKET_TYPE_DATA:
case RXRPC_PACKET_TYPE_ACK:
rxrpc_conn_retransmit(conn, skb);
rxrpc_free_skb(skb);
return 0;
case RXRPC_PACKET_TYPE_ABORT:
if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
return -EPROTO;

10
net/rxrpc/conn_object.c
View File

@ -166,7 +166,15 @@ void __rxrpc_disconnect_call(struct rxrpc_call *call)
/* Save the result of the call so that we can repeat it if necessary
* through the channel, whilst disposing of the actual call record.
*/
chan->last_result = call->local_abort;
chan->last_service_id = call->service_id;
if (call->local_abort) {
chan->last_abort = call->local_abort;
chan->last_type = RXRPC_PACKET_TYPE_ABORT;
} else {
chan->last_seq = call->rx_data_eaten;
chan->last_type = RXRPC_PACKET_TYPE_ACK;
}
/* Sync with rxrpc_conn_retransmit(). */
smp_wmb();
chan->last_call = chan->call_id;
chan->call_id = chan->call_counter;

31
net/rxrpc/input.c
View File

@ -566,7 +566,8 @@ done:
/*
* post connection-level events to the connection
* - this includes challenges, responses and some aborts
* - this includes challenges, responses, some aborts and call terminal packet
* retransmission.
*/
static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
struct sk_buff *skb)
@ -716,18 +717,44 @@ void rxrpc_data_ready(struct sock *sk)
/* Connection-level packet */
_debug("CONN %p {%d}", conn, conn->debug_id);
rxrpc_post_packet_to_conn(conn, skb);
goto out_unlock;
} else {
/* Call-bound packets are routed by connection channel. */
unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
struct rxrpc_channel *chan = &conn->channels[channel];
struct rxrpc_call *call = rcu_dereference(chan->call);
struct rxrpc_call *call;
/* Ignore really old calls */
if (sp->hdr.callNumber < chan->last_call)
goto discard_unlock;
if (sp->hdr.callNumber == chan->last_call) {
/* For the previous service call, if completed
* successfully, we discard all further packets.
*/
if (rxrpc_conn_is_service(call->conn) &&
(chan->last_type == RXRPC_PACKET_TYPE_ACK ||
sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
goto discard_unlock;
/* But otherwise we need to retransmit the final packet
* from data cached in the connection record.
*/
rxrpc_post_packet_to_conn(conn, skb);
goto out_unlock;
}
call = rcu_dereference(chan->call);
if (!call || atomic_read(&call->usage) == 0)
goto cant_route_call;
rxrpc_post_packet_to_call(call, skb);
goto out_unlock;
}
discard_unlock:
rxrpc_free_skb(skb);
out_unlock:
rcu_read_unlock();
out:
return;