linux/net/rxrpc/output.c
David Howells 4e255721d1 rxrpc: Add service upgrade support for client connections
Make it possible for a client to use AuriStor's service upgrade facility.

The client does this by adding an RXRPC_UPGRADE_SERVICE control message to
the first sendmsg() of a call.  This takes no parameters.

When recvmsg() starts returning data from the call, the service ID field in
the returned msg_name will reflect the result of the upgrade attempt.  If
the upgrade was ignored, srx_service will match what was set in the
sendmsg(); if the upgrade happened the srx_service will be altered to
indicate the service the server upgraded to.

Note that:

 (1) The choice of upgrade service is up to the server

 (2) Further client calls to the same server that would share a connection
     are blocked if an upgrade probe is in progress.

 (3) This should only be used to probe the service.  Clients should then
     use the returned service ID in all subsequent communications with that
     server (and not set the upgrade).  Note that the kernel will not
     retain this information should the connection expire from its cache.

 (4) If a server that supports upgrading is replaced by one that doesn't,
     whilst a connection is live, and if the replacement is running, say,
     OpenAFS 1.6.4 or older or an older IBM AFS, then the replacement
     server will not respond to packets sent to the upgraded connection.

     At this point, calls will time out and the server must be reprobed.

Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05 14:30:49 +01:00

468 lines
12 KiB
C

/* RxRPC packet transmission
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/net.h>
#include <linux/gfp.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
struct rxrpc_ack_buffer {
struct rxrpc_wire_header whdr;
struct rxrpc_ackpacket ack;
u8 acks[255];
u8 pad[3];
struct rxrpc_ackinfo ackinfo;
};
struct rxrpc_abort_buffer {
struct rxrpc_wire_header whdr;
__be32 abort_code;
};
/*
* Fill out an ACK packet.
*/
static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
struct rxrpc_ack_buffer *pkt,
rxrpc_seq_t *_hard_ack,
rxrpc_seq_t *_top,
u8 reason)
{
rxrpc_serial_t serial;
rxrpc_seq_t hard_ack, top, seq;
int ix;
u32 mtu, jmax;
u8 *ackp = pkt->acks;
/* Barrier against rxrpc_input_data(). */
serial = call->ackr_serial;
hard_ack = READ_ONCE(call->rx_hard_ack);
top = smp_load_acquire(&call->rx_top);
*_hard_ack = hard_ack;
*_top = top;
pkt->ack.bufferSpace = htons(8);
pkt->ack.maxSkew = htons(call->ackr_skew);
pkt->ack.firstPacket = htonl(hard_ack + 1);
pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
pkt->ack.serial = htonl(serial);
pkt->ack.reason = reason;
pkt->ack.nAcks = top - hard_ack;
if (reason == RXRPC_ACK_PING)
pkt->whdr.flags |= RXRPC_REQUEST_ACK;
if (after(top, hard_ack)) {
seq = hard_ack + 1;
do {
ix = seq & RXRPC_RXTX_BUFF_MASK;
if (call->rxtx_buffer[ix])
*ackp++ = RXRPC_ACK_TYPE_ACK;
else
*ackp++ = RXRPC_ACK_TYPE_NACK;
seq++;
} while (before_eq(seq, top));
}
mtu = call->conn->params.peer->if_mtu;
mtu -= call->conn->params.peer->hdrsize;
jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
pkt->ackinfo.rxMTU = htonl(rxrpc_rx_mtu);
pkt->ackinfo.maxMTU = htonl(mtu);
pkt->ackinfo.rwind = htonl(call->rx_winsize);
pkt->ackinfo.jumbo_max = htonl(jmax);
*ackp++ = 0;
*ackp++ = 0;
*ackp++ = 0;
return top - hard_ack + 3;
}
/*
* Send an ACK call packet.
*/
int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping)
{
struct rxrpc_connection *conn = NULL;
struct rxrpc_ack_buffer *pkt;
struct msghdr msg;
struct kvec iov[2];
rxrpc_serial_t serial;
rxrpc_seq_t hard_ack, top;
size_t len, n;
int ret;
u8 reason;
spin_lock_bh(&call->lock);
if (call->conn)
conn = rxrpc_get_connection_maybe(call->conn);
spin_unlock_bh(&call->lock);
if (!conn)
return -ECONNRESET;
pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
if (!pkt) {
rxrpc_put_connection(conn);
return -ENOMEM;
}
msg.msg_name = &call->peer->srx.transport;
msg.msg_namelen = call->peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
pkt->whdr.epoch = htonl(conn->proto.epoch);
pkt->whdr.cid = htonl(call->cid);
pkt->whdr.callNumber = htonl(call->call_id);
pkt->whdr.seq = 0;
pkt->whdr.type = RXRPC_PACKET_TYPE_ACK;
pkt->whdr.flags = RXRPC_SLOW_START_OK | conn->out_clientflag;
pkt->whdr.userStatus = 0;
pkt->whdr.securityIndex = call->security_ix;
pkt->whdr._rsvd = 0;
pkt->whdr.serviceId = htons(call->service_id);
spin_lock_bh(&call->lock);
if (ping) {
reason = RXRPC_ACK_PING;
} else {
reason = call->ackr_reason;
if (!call->ackr_reason) {
spin_unlock_bh(&call->lock);
ret = 0;
goto out;
}
call->ackr_reason = 0;
}
n = rxrpc_fill_out_ack(call, pkt, &hard_ack, &top, reason);
spin_unlock_bh(&call->lock);
iov[0].iov_base = pkt;
iov[0].iov_len = sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
iov[1].iov_base = &pkt->ackinfo;
iov[1].iov_len = sizeof(pkt->ackinfo);
len = iov[0].iov_len + iov[1].iov_len;
serial = atomic_inc_return(&conn->serial);
pkt->whdr.serial = htonl(serial);
trace_rxrpc_tx_ack(call, serial,
ntohl(pkt->ack.firstPacket),
ntohl(pkt->ack.serial),
pkt->ack.reason, pkt->ack.nAcks);
if (ping) {
call->ping_serial = serial;
smp_wmb();
/* We need to stick a time in before we send the packet in case
* the reply gets back before kernel_sendmsg() completes - but
* asking UDP to send the packet can take a relatively long
* time, so we update the time after, on the assumption that
* the packet transmission is more likely to happen towards the
* end of the kernel_sendmsg() call.
*/
call->ping_time = ktime_get_real();
set_bit(RXRPC_CALL_PINGING, &call->flags);
trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
}
ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
if (ping)
call->ping_time = ktime_get_real();
if (call->state < RXRPC_CALL_COMPLETE) {
if (ret < 0) {
if (ping)
clear_bit(RXRPC_CALL_PINGING, &call->flags);
rxrpc_propose_ACK(call, pkt->ack.reason,
ntohs(pkt->ack.maxSkew),
ntohl(pkt->ack.serial),
true, true,
rxrpc_propose_ack_retry_tx);
} else {
spin_lock_bh(&call->lock);
if (after(hard_ack, call->ackr_consumed))
call->ackr_consumed = hard_ack;
if (after(top, call->ackr_seen))
call->ackr_seen = top;
spin_unlock_bh(&call->lock);
}
}
out:
rxrpc_put_connection(conn);
kfree(pkt);
return ret;
}
/*
* Send an ABORT call packet.
*/
int rxrpc_send_abort_packet(struct rxrpc_call *call)
{
struct rxrpc_connection *conn = NULL;
struct rxrpc_abort_buffer pkt;
struct msghdr msg;
struct kvec iov[1];
rxrpc_serial_t serial;
int ret;
spin_lock_bh(&call->lock);
if (call->conn)
conn = rxrpc_get_connection_maybe(call->conn);
spin_unlock_bh(&call->lock);
if (!conn)
return -ECONNRESET;
msg.msg_name = &call->peer->srx.transport;
msg.msg_namelen = call->peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
pkt.whdr.epoch = htonl(conn->proto.epoch);
pkt.whdr.cid = htonl(call->cid);
pkt.whdr.callNumber = htonl(call->call_id);
pkt.whdr.seq = 0;
pkt.whdr.type = RXRPC_PACKET_TYPE_ABORT;
pkt.whdr.flags = conn->out_clientflag;
pkt.whdr.userStatus = 0;
pkt.whdr.securityIndex = call->security_ix;
pkt.whdr._rsvd = 0;
pkt.whdr.serviceId = htons(call->service_id);
pkt.abort_code = htonl(call->abort_code);
iov[0].iov_base = &pkt;
iov[0].iov_len = sizeof(pkt);
serial = atomic_inc_return(&conn->serial);
pkt.whdr.serial = htonl(serial);
ret = kernel_sendmsg(conn->params.local->socket,
&msg, iov, 1, sizeof(pkt));
rxrpc_put_connection(conn);
return ret;
}
/*
* send a packet through the transport endpoint
*/
int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
bool retrans)
{
struct rxrpc_connection *conn = call->conn;
struct rxrpc_wire_header whdr;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct msghdr msg;
struct kvec iov[2];
rxrpc_serial_t serial;
size_t len;
bool lost = false;
int ret, opt;
_enter(",{%d}", skb->len);
/* Each transmission of a Tx packet needs a new serial number */
serial = atomic_inc_return(&conn->serial);
whdr.epoch = htonl(conn->proto.epoch);
whdr.cid = htonl(call->cid);
whdr.callNumber = htonl(call->call_id);
whdr.seq = htonl(sp->hdr.seq);
whdr.serial = htonl(serial);
whdr.type = RXRPC_PACKET_TYPE_DATA;
whdr.flags = sp->hdr.flags;
whdr.userStatus = 0;
whdr.securityIndex = call->security_ix;
whdr._rsvd = htons(sp->hdr._rsvd);
whdr.serviceId = htons(call->service_id);
if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
sp->hdr.seq == 1)
whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
iov[0].iov_base = &whdr;
iov[0].iov_len = sizeof(whdr);
iov[1].iov_base = skb->head;
iov[1].iov_len = skb->len;
len = iov[0].iov_len + iov[1].iov_len;
msg.msg_name = &call->peer->srx.transport;
msg.msg_namelen = call->peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
/* If our RTT cache needs working on, request an ACK. Also request
* ACKs if a DATA packet appears to have been lost.
*/
if (!(sp->hdr.flags & RXRPC_LAST_PACKET) &&
(retrans ||
call->cong_mode == RXRPC_CALL_SLOW_START ||
(call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
ktime_get_real())))
whdr.flags |= RXRPC_REQUEST_ACK;
if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
static int lose;
if ((lose++ & 7) == 7) {
ret = 0;
lost = true;
goto done;
}
}
_proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
/* send the packet with the don't fragment bit set if we currently
* think it's small enough */
if (iov[1].iov_len >= call->peer->maxdata)
goto send_fragmentable;
down_read(&conn->params.local->defrag_sem);
/* send the packet by UDP
* - returns -EMSGSIZE if UDP would have to fragment the packet
* to go out of the interface
* - in which case, we'll have processed the ICMP error
* message and update the peer record
*/
ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
up_read(&conn->params.local->defrag_sem);
if (ret == -EMSGSIZE)
goto send_fragmentable;
done:
trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
retrans, lost);
if (ret >= 0) {
ktime_t now = ktime_get_real();
skb->tstamp = now;
smp_wmb();
sp->hdr.serial = serial;
if (whdr.flags & RXRPC_REQUEST_ACK) {
call->peer->rtt_last_req = now;
trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
}
}
_leave(" = %d [%u]", ret, call->peer->maxdata);
return ret;
send_fragmentable:
/* attempt to send this message with fragmentation enabled */
_debug("send fragment");
down_write(&conn->params.local->defrag_sem);
switch (conn->params.local->srx.transport.family) {
case AF_INET:
opt = IP_PMTUDISC_DONT;
ret = kernel_setsockopt(conn->params.local->socket,
SOL_IP, IP_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
if (ret == 0) {
ret = kernel_sendmsg(conn->params.local->socket, &msg,
iov, 2, len);
opt = IP_PMTUDISC_DO;
kernel_setsockopt(conn->params.local->socket, SOL_IP,
IP_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
}
break;
#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
opt = IPV6_PMTUDISC_DONT;
ret = kernel_setsockopt(conn->params.local->socket,
SOL_IPV6, IPV6_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
if (ret == 0) {
ret = kernel_sendmsg(conn->params.local->socket, &msg,
iov, 1, iov[0].iov_len);
opt = IPV6_PMTUDISC_DO;
kernel_setsockopt(conn->params.local->socket,
SOL_IPV6, IPV6_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
}
break;
#endif
}
up_write(&conn->params.local->defrag_sem);
goto done;
}
/*
* reject packets through the local endpoint
*/
void rxrpc_reject_packets(struct rxrpc_local *local)
{
struct sockaddr_rxrpc srx;
struct rxrpc_skb_priv *sp;
struct rxrpc_wire_header whdr;
struct sk_buff *skb;
struct msghdr msg;
struct kvec iov[2];
size_t size;
__be32 code;
_enter("%d", local->debug_id);
iov[0].iov_base = &whdr;
iov[0].iov_len = sizeof(whdr);
iov[1].iov_base = &code;
iov[1].iov_len = sizeof(code);
size = sizeof(whdr) + sizeof(code);
msg.msg_name = &srx.transport;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
memset(&whdr, 0, sizeof(whdr));
whdr.type = RXRPC_PACKET_TYPE_ABORT;
while ((skb = skb_dequeue(&local->reject_queue))) {
rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
sp = rxrpc_skb(skb);
if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
msg.msg_namelen = srx.transport_len;
code = htonl(skb->priority);
whdr.epoch = htonl(sp->hdr.epoch);
whdr.cid = htonl(sp->hdr.cid);
whdr.callNumber = htonl(sp->hdr.callNumber);
whdr.serviceId = htons(sp->hdr.serviceId);
whdr.flags = sp->hdr.flags;
whdr.flags ^= RXRPC_CLIENT_INITIATED;
whdr.flags &= RXRPC_CLIENT_INITIATED;
kernel_sendmsg(local->socket, &msg, iov, 2, size);
}
rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
}
_leave("");
}