linux/net/tipc/msg.c
Jon Paul Maloy 50100a5e39 tipc: use pseudo message to wake up sockets after link congestion
The current link implementation keeps a linked list of blocked ports/
sockets that is populated when there is link congestion. The purpose
of this is to let the link know which users to wake up when the
congestion abates.

This adds unnecessary complexity to the data structure and the code,
since it forces us to involve the link each time we want to delete
a socket. It also forces us to grab the spinlock port_lock within
the scope of node_lock. We want to get rid of this direct dependence,
as well as the deadlock hazard resulting from the usage of port_lock.

In this commit, we instead let the link keep list of a "wakeup" pseudo
messages for use in such situations. Those messages are sent to the
pending sockets via the ordinary message reception path, and wake up
the socket's owner when they are received.

This enables us to get rid of the 'waiting_ports' linked lists in struct
tipc_port that manifest this direct reference. As a consequence, we can
eliminate another BH entry into the socket, and hence the need to grab
port_lock. This is a further step in our effort to remove port_lock
altogether.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-23 11:18:33 -07:00

463 lines
12 KiB
C

/*
* net/tipc/msg.c: TIPC message header routines
*
* Copyright (c) 2000-2006, 2014, Ericsson AB
* Copyright (c) 2005, 2010-2011, Wind River Systems
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "core.h"
#include "msg.h"
#include "addr.h"
#include "name_table.h"
#define MAX_FORWARD_SIZE 1024
static unsigned int align(unsigned int i)
{
return (i + 3) & ~3u;
}
void tipc_msg_init(struct tipc_msg *m, u32 user, u32 type, u32 hsize,
u32 destnode)
{
memset(m, 0, hsize);
msg_set_version(m);
msg_set_user(m, user);
msg_set_hdr_sz(m, hsize);
msg_set_size(m, hsize);
msg_set_prevnode(m, tipc_own_addr);
msg_set_type(m, type);
if (hsize > SHORT_H_SIZE) {
msg_set_orignode(m, tipc_own_addr);
msg_set_destnode(m, destnode);
}
}
struct sk_buff *tipc_msg_create(uint user, uint type, uint hdr_sz,
uint data_sz, u32 dnode, u32 onode,
u32 dport, u32 oport, int errcode)
{
struct tipc_msg *msg;
struct sk_buff *buf;
buf = tipc_buf_acquire(hdr_sz + data_sz);
if (unlikely(!buf))
return NULL;
msg = buf_msg(buf);
tipc_msg_init(msg, user, type, hdr_sz, dnode);
msg_set_size(msg, hdr_sz + data_sz);
msg_set_prevnode(msg, onode);
msg_set_origport(msg, oport);
msg_set_destport(msg, dport);
msg_set_errcode(msg, errcode);
if (hdr_sz > SHORT_H_SIZE) {
msg_set_orignode(msg, onode);
msg_set_destnode(msg, dnode);
}
return buf;
}
/* tipc_buf_append(): Append a buffer to the fragment list of another buffer
* @*headbuf: in: NULL for first frag, otherwise value returned from prev call
* out: set when successful non-complete reassembly, otherwise NULL
* @*buf: in: the buffer to append. Always defined
* out: head buf after sucessful complete reassembly, otherwise NULL
* Returns 1 when reassembly complete, otherwise 0
*/
int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
{
struct sk_buff *head = *headbuf;
struct sk_buff *frag = *buf;
struct sk_buff *tail;
struct tipc_msg *msg;
u32 fragid;
int delta;
bool headstolen;
if (!frag)
goto err;
msg = buf_msg(frag);
fragid = msg_type(msg);
frag->next = NULL;
skb_pull(frag, msg_hdr_sz(msg));
if (fragid == FIRST_FRAGMENT) {
if (unlikely(head))
goto err;
if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
goto err;
head = *headbuf = frag;
skb_frag_list_init(head);
TIPC_SKB_CB(head)->tail = NULL;
*buf = NULL;
return 0;
}
if (!head)
goto err;
if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
kfree_skb_partial(frag, headstolen);
} else {
tail = TIPC_SKB_CB(head)->tail;
if (!skb_has_frag_list(head))
skb_shinfo(head)->frag_list = frag;
else
tail->next = frag;
head->truesize += frag->truesize;
head->data_len += frag->len;
head->len += frag->len;
TIPC_SKB_CB(head)->tail = frag;
}
if (fragid == LAST_FRAGMENT) {
*buf = head;
TIPC_SKB_CB(head)->tail = NULL;
*headbuf = NULL;
return 1;
}
*buf = NULL;
return 0;
err:
pr_warn_ratelimited("Unable to build fragment list\n");
kfree_skb(*buf);
kfree_skb(*headbuf);
*buf = *headbuf = NULL;
return 0;
}
/**
* tipc_msg_build - create buffer chain containing specified header and data
* @mhdr: Message header, to be prepended to data
* @iov: User data
* @offset: Posision in iov to start copying from
* @dsz: Total length of user data
* @pktmax: Max packet size that can be used
* @chain: Buffer or chain of buffers to be returned to caller
* Returns message data size or errno: -ENOMEM, -EFAULT
*/
int tipc_msg_build(struct tipc_msg *mhdr, struct iovec const *iov,
int offset, int dsz, int pktmax , struct sk_buff **chain)
{
int mhsz = msg_hdr_sz(mhdr);
int msz = mhsz + dsz;
int pktno = 1;
int pktsz;
int pktrem = pktmax;
int drem = dsz;
struct tipc_msg pkthdr;
struct sk_buff *buf, *prev;
char *pktpos;
int rc;
uint chain_sz = 0;
msg_set_size(mhdr, msz);
/* No fragmentation needed? */
if (likely(msz <= pktmax)) {
buf = tipc_buf_acquire(msz);
*chain = buf;
if (unlikely(!buf))
return -ENOMEM;
skb_copy_to_linear_data(buf, mhdr, mhsz);
pktpos = buf->data + mhsz;
TIPC_SKB_CB(buf)->chain_sz = 1;
if (!dsz || !memcpy_fromiovecend(pktpos, iov, offset, dsz))
return dsz;
rc = -EFAULT;
goto error;
}
/* Prepare reusable fragment header */
tipc_msg_init(&pkthdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
INT_H_SIZE, msg_destnode(mhdr));
msg_set_size(&pkthdr, pktmax);
msg_set_fragm_no(&pkthdr, pktno);
/* Prepare first fragment */
*chain = buf = tipc_buf_acquire(pktmax);
if (!buf)
return -ENOMEM;
chain_sz = 1;
pktpos = buf->data;
skb_copy_to_linear_data(buf, &pkthdr, INT_H_SIZE);
pktpos += INT_H_SIZE;
pktrem -= INT_H_SIZE;
skb_copy_to_linear_data_offset(buf, INT_H_SIZE, mhdr, mhsz);
pktpos += mhsz;
pktrem -= mhsz;
do {
if (drem < pktrem)
pktrem = drem;
if (memcpy_fromiovecend(pktpos, iov, offset, pktrem)) {
rc = -EFAULT;
goto error;
}
drem -= pktrem;
offset += pktrem;
if (!drem)
break;
/* Prepare new fragment: */
if (drem < (pktmax - INT_H_SIZE))
pktsz = drem + INT_H_SIZE;
else
pktsz = pktmax;
prev = buf;
buf = tipc_buf_acquire(pktsz);
if (!buf) {
rc = -ENOMEM;
goto error;
}
chain_sz++;
prev->next = buf;
msg_set_type(&pkthdr, FRAGMENT);
msg_set_size(&pkthdr, pktsz);
msg_set_fragm_no(&pkthdr, ++pktno);
skb_copy_to_linear_data(buf, &pkthdr, INT_H_SIZE);
pktpos = buf->data + INT_H_SIZE;
pktrem = pktsz - INT_H_SIZE;
} while (1);
TIPC_SKB_CB(*chain)->chain_sz = chain_sz;
msg_set_type(buf_msg(buf), LAST_FRAGMENT);
return dsz;
error:
kfree_skb_list(*chain);
*chain = NULL;
return rc;
}
/**
* tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
* @bbuf: the existing buffer ("bundle")
* @buf: buffer to be appended
* @mtu: max allowable size for the bundle buffer
* Consumes buffer if successful
* Returns true if bundling could be performed, otherwise false
*/
bool tipc_msg_bundle(struct sk_buff *bbuf, struct sk_buff *buf, u32 mtu)
{
struct tipc_msg *bmsg = buf_msg(bbuf);
struct tipc_msg *msg = buf_msg(buf);
unsigned int bsz = msg_size(bmsg);
unsigned int msz = msg_size(msg);
u32 start = align(bsz);
u32 max = mtu - INT_H_SIZE;
u32 pad = start - bsz;
if (likely(msg_user(msg) == MSG_FRAGMENTER))
return false;
if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))
return false;
if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
return false;
if (likely(msg_user(bmsg) != MSG_BUNDLER))
return false;
if (likely(msg_type(bmsg) != BUNDLE_OPEN))
return false;
if (unlikely(skb_tailroom(bbuf) < (pad + msz)))
return false;
if (unlikely(max < (start + msz)))
return false;
skb_put(bbuf, pad + msz);
skb_copy_to_linear_data_offset(bbuf, start, buf->data, msz);
msg_set_size(bmsg, start + msz);
msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
bbuf->next = buf->next;
kfree_skb(buf);
return true;
}
/**
* tipc_msg_make_bundle(): Create bundle buf and append message to its tail
* @buf: buffer to be appended and replaced
* @mtu: max allowable size for the bundle buffer, inclusive header
* @dnode: destination node for message. (Not always present in header)
* Replaces buffer if successful
* Returns true if sucess, otherwise false
*/
bool tipc_msg_make_bundle(struct sk_buff **buf, u32 mtu, u32 dnode)
{
struct sk_buff *bbuf;
struct tipc_msg *bmsg;
struct tipc_msg *msg = buf_msg(*buf);
u32 msz = msg_size(msg);
u32 max = mtu - INT_H_SIZE;
if (msg_user(msg) == MSG_FRAGMENTER)
return false;
if (msg_user(msg) == CHANGEOVER_PROTOCOL)
return false;
if (msg_user(msg) == BCAST_PROTOCOL)
return false;
if (msz > (max / 2))
return false;
bbuf = tipc_buf_acquire(max);
if (!bbuf)
return false;
skb_trim(bbuf, INT_H_SIZE);
bmsg = buf_msg(bbuf);
tipc_msg_init(bmsg, MSG_BUNDLER, BUNDLE_OPEN, INT_H_SIZE, dnode);
msg_set_seqno(bmsg, msg_seqno(msg));
msg_set_ack(bmsg, msg_ack(msg));
msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
bbuf->next = (*buf)->next;
tipc_msg_bundle(bbuf, *buf, mtu);
*buf = bbuf;
return true;
}
/**
* tipc_msg_reverse(): swap source and destination addresses and add error code
* @buf: buffer containing message to be reversed
* @dnode: return value: node where to send message after reversal
* @err: error code to be set in message
* Consumes buffer if failure
* Returns true if success, otherwise false
*/
bool tipc_msg_reverse(struct sk_buff *buf, u32 *dnode, int err)
{
struct tipc_msg *msg = buf_msg(buf);
uint imp = msg_importance(msg);
struct tipc_msg ohdr;
uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE);
if (skb_linearize(buf))
goto exit;
if (msg_dest_droppable(msg))
goto exit;
if (msg_errcode(msg))
goto exit;
memcpy(&ohdr, msg, msg_hdr_sz(msg));
imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
if (msg_isdata(msg))
msg_set_importance(msg, imp);
msg_set_errcode(msg, err);
msg_set_origport(msg, msg_destport(&ohdr));
msg_set_destport(msg, msg_origport(&ohdr));
msg_set_prevnode(msg, tipc_own_addr);
if (!msg_short(msg)) {
msg_set_orignode(msg, msg_destnode(&ohdr));
msg_set_destnode(msg, msg_orignode(&ohdr));
}
msg_set_size(msg, msg_hdr_sz(msg) + rdsz);
skb_trim(buf, msg_size(msg));
skb_orphan(buf);
*dnode = msg_orignode(&ohdr);
return true;
exit:
kfree_skb(buf);
return false;
}
/**
* tipc_msg_eval: determine fate of message that found no destination
* @buf: the buffer containing the message.
* @dnode: return value: next-hop node, if message to be forwarded
* @err: error code to use, if message to be rejected
*
* Does not consume buffer
* Returns 0 (TIPC_OK) if message ok and we can try again, -TIPC error
* code if message to be rejected
*/
int tipc_msg_eval(struct sk_buff *buf, u32 *dnode)
{
struct tipc_msg *msg = buf_msg(buf);
u32 dport;
if (msg_type(msg) != TIPC_NAMED_MSG)
return -TIPC_ERR_NO_PORT;
if (skb_linearize(buf))
return -TIPC_ERR_NO_NAME;
if (msg_data_sz(msg) > MAX_FORWARD_SIZE)
return -TIPC_ERR_NO_NAME;
if (msg_reroute_cnt(msg) > 0)
return -TIPC_ERR_NO_NAME;
*dnode = addr_domain(msg_lookup_scope(msg));
dport = tipc_nametbl_translate(msg_nametype(msg),
msg_nameinst(msg),
dnode);
if (!dport)
return -TIPC_ERR_NO_NAME;
msg_incr_reroute_cnt(msg);
msg_set_destnode(msg, *dnode);
msg_set_destport(msg, dport);
return TIPC_OK;
}
/* tipc_msg_reassemble() - clone a buffer chain of fragments and
* reassemble the clones into one message
*/
struct sk_buff *tipc_msg_reassemble(struct sk_buff *chain)
{
struct sk_buff *buf = chain;
struct sk_buff *frag = buf;
struct sk_buff *head = NULL;
int hdr_sz;
/* Copy header if single buffer */
if (!buf->next) {
hdr_sz = skb_headroom(buf) + msg_hdr_sz(buf_msg(buf));
return __pskb_copy(buf, hdr_sz, GFP_ATOMIC);
}
/* Clone all fragments and reassemble */
while (buf) {
frag = skb_clone(buf, GFP_ATOMIC);
if (!frag)
goto error;
frag->next = NULL;
if (tipc_buf_append(&head, &frag))
break;
if (!head)
goto error;
buf = buf->next;
}
return frag;
error:
pr_warn("Failed do clone local mcast rcv buffer\n");
kfree_skb(head);
return NULL;
}