As a consequence of the recently introduced serialized access
to the socket in commit 8d94168a761819d10252bab1f8de6d7b202c3baa
("tipc: same receive code path for connection protocol and data
messages") we can make a number of simplifications in the
detection and handling of connection congestion situations.
- We don't need to keep two counters, one for sent messages and one
for acked messages. There is no longer any risk for races between
acknowledge messages arriving in BH and data message sending
running in user context. So we merge this into one counter,
'sent_unacked', which is incremented at sending and subtracted
from at acknowledge reception.
- We don't need to set the 'congested' field in tipc_port to
true before we sent the message, and clear it when sending
is successful. (As a matter of fact, it was never necessary;
the field was set in link_schedule_port() before any wakeup
could arrive anyway.)
- We keep the conditions for link congestion and connection connection
congestion separated. There would otherwise be a risk that an arriving
acknowledge message may wake up a user sleeping because of link
congestion.
- We can simplify reception of acknowledge messages.
We also make some cosmetic/structural changes:
- We rename the 'congested' field to the more correct 'link_cong´.
- We rename 'conn_unacked' to 'rcv_unacked'
- We move the above mentioned fields from struct tipc_port to
struct tipc_sock.
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>
We simplify the code for receiving connection probes, leveraging the
recently introduced tipc_msg_reverse() function. We also stick to
the principle of sending a possible response message directly from
the calling (tipc_sk_rcv or backlog_rcv) functions, hence making
the call chain shallower and easier to follow.
We make one small protocol change here, allowed according to
the spec. If a protocol message arrives from a remote socket that
is not the one we are connected to, we are currently generating a
connection abort message and send it to the source. This behavior
is unnecessary, and might even be a security risk, so instead we
now choose to only ignore the message. The consequnce for the sender
is that he will need longer time to discover his mistake (until the
next timeout), but this is an extreme corner case, and may happen
anyway under other circumstances, so we deem this change acceptable.
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>
In order to reduce complexity and save a call level during message
reception at port/socket level, we remove the function tipc_port_rcv()
and merge its functionality into tipc_sk_rcv().
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The function net/core/sock.c::__release_sock() runs a tight loop
to move buffers from the socket backlog queue to the receive queue.
As a security measure, sk_backlog.len of the receiving socket
is not set to zero until after the loop is finished, i.e., until
the whole backlog queue has been transferred to the receive queue.
During this transfer, the data that has already been moved is counted
both in the backlog queue and the receive queue, hence giving an
incorrect picture of the available queue space for new arriving buffers.
This leads to unnecessary rejection of buffers by sk_add_backlog(),
which in TIPC leads to unnecessarily broken connections.
In this commit, we compensate for this double accounting by adding
a counter that keeps track of it. The function socket.c::backlog_rcv()
receives buffers one by one from __release_sock(), and adds them to the
socket receive queue. If the transfer is successful, it increases a new
atomic counter 'tipc_sock::dupl_rcvcnt' with 'truesize' of the
transferred buffer. If a new buffer arrives during this transfer and
finds the socket busy (owned), we attempt to add it to the backlog.
However, when sk_add_backlog() is called, we adjust the 'limit'
parameter with the value of the new counter, so that the risk of
inadvertent rejection is eliminated.
It should be noted that this change does not invalidate the original
purpose of zeroing 'sk_backlog.len' after the full transfer. We set an
upper limit for dupl_rcvcnt, so that if a 'wild' sender (i.e., one that
doesn't respect the send window) keeps pumping in buffers to
sk_add_backlog(), he will eventually reach an upper limit,
(2 x TIPC_CONN_OVERLOAD_LIMIT). After that, no messages can be added
to the backlog, and the connection will be broken. Ordinary, well-
behaved senders will never reach this buffer limit at all.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The practice of naming variables in TIPC is inconistent, sometimes
even within the same file.
In this commit we align variable names and declarations within
socket.c, and function and macro names within socket.h. We also
reduce the number of conversion macros to two, in order to make
usage less obsure.
These changes are purely cosmetic.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Due to the original one-to-many relation between port and user API
layers, upcalls to the API have been performed via function pointers,
installed in struct tipc_port at creation. Since this relation now
always is one-to-one, we can instead use ordinary function calls.
We remove the function pointers 'dispatcher' and ´wakeup' from
struct tipc_port, and replace them with calls to the renamed
functions tipc_sk_rcv() and tipc_sk_wakeup().
At the same time we change the name and signature of the functions
tipc_createport() and tipc_deleteport() to reflect their new role
as mere initialization/destruction functions.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After the removal of the tipc native API the relation between
a tipc_port and its API types is strictly one-to-one, i.e, the
latter can now only be a socket API. There is therefore no need
to allocate struct tipc_port and struct sock independently.
In this commit, we aggregate struct tipc_port into struct tipc_sock,
hence saving both CPU cycles and structure complexity.
There are no functional changes in this commit, except for the
elimination of the separate allocation/freeing of tipc_port.
All other changes are just adaptatons to the new data structure.
This commit also opens up for further code simplifications and
code volume reduction, something we will do in later commits.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Jon Paul Maloy