Currently the code to translate host side addresses and ports to guest side
addresses and ports, and vice versa, is scattered across the TCP code.
This includes both port redirection as controlled by the -t and -T options,
and our special case NAT controlled by the --no-map-gw option.
Gather this logic into fwd_nat_from_*() functions for each input
interface in fwd.c which take protocol and address information for the
initiating side and generates the pif and address information for the
forwarded side. This performs any NAT or port forwarding needed.
We create a flow_target() helper which applies those forwarding functions
as needed to automatically move a flow from INI to TGT state.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Since we're now constructing socket addresses based on information in the
flowside, we no longer need an explicit flag to tell if we're dealing with
an IPv4 or IPv6 connection. Hence, drop the now unused SPLICE_V6 flag.
As well as just simplifying the code, this allows for possible future
extensions where we could splice an IPv4 connection to an IPv6 connection
or vice versa.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Require the address and port information for the target (non
initiating) side to be populated when a flow enters TGT state.
Implement that for TCP and ICMP. For now this leaves some information
redundantly recorded in both generic and type specific fields. We'll
fix that in later patches.
For TCP we now use the information from the flow to construct the
destination socket address in both tcp_conn_from_tap() and
tcp_splice_connect().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Both the events and flags fields in tcp_splice_conn have several bits
which are per-side, e.g. OUT_WAIT_0 for side 0 and OUT_WAIT_1 for side 1.
This necessitates some rather awkward ternary expressions when we need
to get the relevant bit for a particular side.
Simplify this by using a parameterised macro for the bit values. This
needs a ternary expression inside the macros, but makes the places we use
it substantially clearer.
That simplification in turn allows us to use a loop across each side to
implement several things which are currently open coded to do equivalent
things for each side in turn.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We have a handful of places where we use a loop to step through each side
of a flow or flows, and we're probably going to have mroe in future.
Introduce a macro to implement this loop for convenience.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In various places we have variables named 'side' or similar which always
have the value 0 or 1 (INISIDE or TGTSIDE). Given a flow, this refers to
a specific side of it. Upcoming flow table work will make it more useful
for "side" to refer to a specific side of a specific flow. To make things
less confusing then, prefer the name term "side index" and name 'sidei' for
variables with just the 0 or 1 value.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Fixed minor detail in comment to struct flow_common]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
TCP (both regular and spliced) and ICMP both have macros to retrieve the
relevant protcol specific flow structure from a flow index. In most cases
what we actually want is to get the specific flow from a sidx. Replace
those simple macros with a more precise inline, which also asserts that
the flow is of the type we expect.
While we're they're also add a pif_at_sidx() helper to get the interface of
a specific flow & side, which is useful in some places.
Finally, fix some minor style issues in the comments on some of the
existing sidx related helpers.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Spotted by Coverity, harmless as we would consider that successful
and check on the socket later from the timer, but printing a debug
message in that case is definitely wise, should it ever happen.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
We have several functions which are used as callbacks for NS_CALL() which
only read their void * parameter, they don't write it. The
constParameterCallback warning in cppcheck 2.14.1 complains that this
parameter could be const void *, also pointing out that that would require
casting the function pointer when used as a callback.
Casting the function pointers seems substantially uglier than using a
non-const void * as the parameter, especially since in each case we cast
the void * to a const pointer of specific type immediately. So, suppress
these errors.
I think it would make logical sense to suppress this globally, but that
would cause unmatchedSuppression errors on earlier cppcheck versions. So,
instead individually suppress it, along with unmatchedSuppression in the
relevant places.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We globally disabled this, with a justification lumped together with
several checks about braces. They don't really go together, the others
are essentially a stylistic choice which doesn't match our style. Omitting
brackets on macro parameters can lead to real and hard to track down bugs
if an expression is ever passed to the macro instead of a plain identifier.
We've only gotten away with the macros which trigger the warning, because
of other conventions its been unlikely to invoke them with anything other
than a simple identifier. Fix the macros, and enable the warning for the
future.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently we have no generic information flows apart from the type and
state, everything else is specific to the flow type. Start introducing
generic flow information by recording the pifs which the flow connects.
To keep track of what information is valid, introduce new flow states:
INI for when the initiating side information is complete, and TGT for
when both sides information is complete, but we haven't chosen the
flow type yet. For now, these states don't do an awful lot, but
they'll become more important as we add more generic information.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Each flow in the flow table has two sides, 0 and 1, representing the
two interfaces between which passt/pasta will forward data for that flow.
Which side is which is currently up to the protocol specific code: TCP
uses side 0 for the host/"sock" side and 1 for the guest/"tap" side, except
for spliced connections where it uses 0 for the initiating side and 1 for
the target side. ICMP also uses 0 for the host/"sock" side and 1 for the
guest/"tap" side, but in its case the latter is always also the initiating
side.
Make this generically consistent by always using side 0 for the initiating
side and 1 for the target side. This doesn't simplify a lot for now, and
arguably makes TCP slightly more complex, since we add an extra field to
the connection structure to record which is the guest facing side. This is
an interim change, which we'll be able to remove later.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>q
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Flows move over several different states in their lifetime. The rules for
these are documented in comments, but they're pretty complex and a number
of the transitions are implicit, which makes this pretty fragile and
error prone.
Change the code to explicitly track the states in a field. Make all
transitions explicit and logged. To the extent that it's practical in C,
enforce what can and can't be done in various states with ASSERT()s.
While we're at it, tweak the docs to clarify the restrictions on each state
a bit.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The flow dispatches deferred and timer handling for flows centrally, but
needs to call into protocol specific code for the handling of individual
flows. Currently this passes a general union flow *. It makes more sense
to pass the specific relevant flow type structure. That brings the check
on the flow type adjacent to casting to the union variant which it tags.
Arguably, this is a slight abstraction violation since it involves the
generic flow code using protocol specific types. It's already calling into
protocol specific functions, so I don't think this really makes any
difference.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In tcp_splice_sock_handler(), if we get EAGAIN on the second splice(),
from pipe to receiving socket, that doesn't necessarily mean that the
pipe is empty: the receiver buffer might be full instead.
Hence, we can't use the 'never_read' flag to decide that there's
nothing to wait for: even if we didn't read anything from the sending
side in a given iteration, we might still have data to send in the
pipe. Use read/written counters, instead.
This fixes an issue where large bulk transfers would occasionally
hang. From a corresponding strace:
0.000061 epoll_wait(4, [{events=EPOLLOUT, data={u32=29442, u64=12884931330}}], 8, 1000) = 1
0.005003 epoll_ctl(4, EPOLL_CTL_MOD, 211, {events=EPOLLIN|EPOLLRDHUP, data={u32=54018, u64=8589988610}}) = 0
0.000089 epoll_ctl(4, EPOLL_CTL_MOD, 115, {events=EPOLLIN|EPOLLRDHUP, data={u32=29442, u64=12884931330}}) = 0
0.000081 splice(211, NULL, 151, NULL, 1048576, SPLICE_F_MOVE|SPLICE_F_NONBLOCK) = -1 EAGAIN (Resource temporarily unavailable)
0.000073 splice(150, NULL, 115, NULL, 1048576, SPLICE_F_MOVE|SPLICE_F_NONBLOCK) = 1048576
0.000087 splice(211, NULL, 151, NULL, 1048576, SPLICE_F_MOVE|SPLICE_F_NONBLOCK) = -1 EAGAIN (Resource temporarily unavailable)
0.000045 splice(150, NULL, 115, NULL, 1048576, SPLICE_F_MOVE|SPLICE_F_NONBLOCK) = 520415
0.000060 splice(211, NULL, 151, NULL, 1048576, SPLICE_F_MOVE|SPLICE_F_NONBLOCK) = -1 EAGAIN (Resource temporarily unavailable)
0.000044 splice(150, NULL, 115, NULL, 1048576, SPLICE_F_MOVE|SPLICE_F_NONBLOCK) = -1 EAGAIN (Resource temporarily unavailable)
0.000044 epoll_wait(4, [], 8, 1000) = 0
we're reading from socket 211 into to the pipe end numbered 151,
which connects to pipe end 150, and from there we're writing into
socket 115.
We initially drop EPOLLOUT from the set of monitored flags for socket
115, because it already signaled it's ready for output. Then we read
nothing from socket 211 (the sender had nothing to send), and we keep
emptying the pipe into socket 115 (first 1048576 bytes, then 520415
bytes).
This call of tcp_splice_sock_handler() ends with EAGAIN on the writing
side, and we just exit this function without setting the OUT_WAIT_1
flag (and, in turn, EPOLLOUT for socket 115). However, it turns out,
the pipe wasn't actually emptied, and while socket 211 had nothing
more to send, we should have waited on socket 115 to be ready for
output again.
As a further step, we could consider not clearing EPOLLOUT at all,
unless the read/written counters match, but I'm first trying to fix
this ugly issue with a minimal patch.
Link: https://github.com/containers/podman/issues/22575
Link: https://github.com/containers/podman/issues/22593
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
When I switched from 'uname -m' to 'gcc -dumpmachine' to fetch the
architecture name for, among others, seccomp.sh, I didn't realise
that "armv6l" and "armv7l" are just Linux kernel names -- compilers
just call that "arm".
Fix the "syscalls" annotation we use to define seccomp profiles
accordingly, otherwise pasta will be terminated on sigreturn() on
armv6l and armv7l.
Fixes: 213c397492 ("passt, pasta: Run-time selection of AVX2 build")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Introduce ip.[ch] file to encapsulate IP protocol handling functions and
structures. Modify various files to include the new header ip.h when
it's needed.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-ID: <20240303135114.1023026-5-lvivier@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
tcp_listen_handler() uses the epoll reference for the listening socket
it handles, and also passes on one variant of it to
tcp_tap_conn_from_sock() and tcp_splice_conn_from_sock(). The latter
two functions only need a couple of specific fields from the
reference.
Pass those specific values instead of the whole reference, which
localises the handling of the listening (as opposed to accepted)
socket and its reference entirely within tcp_listen_handler().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This makes several tweaks to improve the logic which decides whether
we're able to use the splice method for a new connection.
* Rather than only calling tcp_splice_conn_from_sock() in pasta mode, we
check for pasta mode within it, better localising the checks.
* Previously if we got a connection from a non-loopback address we'd
always fall back to the "tap" path, even if the connection was on a
socket in the namespace. If we did get a non-loopback address on a
namespace socket, something has gone wrong and the "tap" path certainly
won't be able to handle it. Report the error and close, rather than
passing it along to tap.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This makes a number of changes to improve error reporting while
connecting a new spliced socket:
* We use flow_err() and similar functions so all messages include info
on which specific flow was affected
* We use strerror() to interpret raw error values
* We now report errors on connection (at "trace" level, since this would
allow spamming the logs)
* We also look up and report some details on EPOLLERR events, which can
include connection errors, since we use a non-blocking connect(). Again
we use "trace" level since this can spam the logs.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently creating the connected socket for a splice is split between
tcp_splice_conn_from_sock(), which opens the socket, and
tcp_splice_connect() which connects it. Alter tcp_splice_connect() to
open its own socket based on an address family and pif we pass it.
This does require a second conditional on pif, but makes for a more
logical split of functionality: tcp_splice_conn_from_sock() picks the
target, tcp_splice_connect() creates the connection. While we're
there improve reporting of errors
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The only caller of tcp_splice_new() is tcp_splice_conn_from_sock().
Both are quite short, and the division of responsibilities between the
two isn't particularly obvious. Simplify by merging the former into
the latter.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In tcp_splice_conn_from_sock(), the 'port' variable stores the source
port of the connection on the originating side. In tcp_splice_new(),
called directly from it, the 'port' parameter gives the _destination_
port of the originating connection and is then updated to the
destination port of the connection on the other side.
Similarly, in tcp_splice_conn_from_sock(), 's' is the fd of the
accetped socket (on side 0), whereas in tcp_splice_new(), 's' is the
fd of the connecting socket (side 1).
I, for one, find having the same variable name with different meanings
in such close proximity in the flow of control pretty confusing.
Alter the names for greater specificity and clarity.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Our allocation scheme for flow entries means there are some
non-obvious constraints on when what things can be done with an entry.
Add a big doc comment explaining the life cycle.
In addition, make a FLOW_START() macro to mark one of the important
transitions. This encourages correct usage, by making it natural to
only access the flow type specific structure after calling it. It
also logs that a new flow has been created, which is useful for
debugging.
We also add logging when a flow's lifecycle ends. This doesn't need a
new helper, because it can only happen either from flow_alloc_cancel()
or from the flow deferred handler.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In tcp_splice_conn_from_sock() we can call flow_trace() if there's an
error setting TCP_QUICKACK. However, we do so before we've set the
flow type in the flow entry. That means that flow_trace() will print
nonsense when it tries to print the flow type.
There's no reason the setsockopt() has to happen before initialising
the flow entry, so just move it after.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently tcp_splice_flow_defer() contains specific logic to determine
if we're far enough initialised that we need to close pipes and/or
sockets. This is potentially fragile if we change something about the
order in which we do things. We can simplify this by initialising the
pipe and socket fields to -1 very early, then close()ing them if and
only if they're non-negative.
This lets us remove a special case cleanup if our connect() fails.
This will already trigger a CLOSING event, and the socket fd in
question is populated in the connection structure. Thus we can let
the new cleanup logic handle it rather than requiring an explicit
close().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The epoll references for both TCP listening sockets and UDP sockets
includes a port number. This gives the destination port that traffic
to that socket will be sent to on the other side. That will usually
be the same as the socket's bound port, but might not if the -t, -u,
-T or -U options are given with different original and forwarded port
numbers.
As we move towards a more flexible forwarding model for passt, it's
going to become possible for that destination port to vary depending
on more things (for example the source or destination address). So,
it will no longer make sense to have a fixed value for a listening
socket.
Change to simpler semantics where this field in the reference gives
the bound port of the socket. We apply the translations to the
correct destination port later on, when we're actually forwarding.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
There are a number of places where we want to handle either a
sockaddr_in or a sockaddr_in6. In some of those we use a void *,
which works ok and matches some standard library interfaces, but
doesn't give a signature level hint that we're dealing with only
sockaddr_in or sockaddr_in6, not (say) sockaddr_un or another type of
socket address. Other places we use a sockaddr_storage, which also
works, but has the same problem in addition to allocating more on the
stack than we need to.
Introduce union sockaddr_inany to explictly handle this case: it has
variants for sockaddr_in and sockaddr_in6. Use it in a number of
places where it's easy to do so.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Add helpers to determine if an inany is loopback, unspecified or
multicast, regardless of whether it's a "true" IPv6 address or an IPv4
address represented as v4-mapped.
Use the loopback helper to simplify tcp_splice_conn_from_sock() slightly.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We maintain pools of ready-to-connect sockets in both the original and
(for pasta) guest namespace to reduce latency when starting new TCP
connections. If we exhaust those pools we have to take a higher
latency path to get a new socket.
Currently we open-code that fallback in the places we need it. To improve
clarity encapsulate that into helper functions. While we're at it, give
those helpers clearer error reporting.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently if tcp_sock_refill_pool() is unable to fill all the slots in the
pool, it will silently exit. This might lead to a later attempt to get
fds from the pool to fail at which point it will be harder to tell what
originally went wrong.
Instead add warnings if we're unable to refill any of the socket pools when
requested. We have tcp_sock_refill_pool() return an error and report it
in the callers, because those callers have more context allowing for a
more useful message.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Sometimes we use sa_family_t for variables and parameters containing a
socket address family, other times we use a plain int. Since sa_family_t
is what's actually used in struct sockaddr and friends, standardise on
that.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently we always keep the flow table maximally compact: that is all the
active entries are contiguous at the start of the table. Doing this
sometimes requires moving an entry when one is freed. That's kind of
fiddly, and potentially expensive: it requires updating the hash table for
the new location, and depending on flow type, it may require EPOLL_CTL_MOD,
system calls to update epoll tags with the new location too.
Implement a new way of managing the flow table that doesn't ever move
entries. It attempts to maintain some compactness by always using the
first free slot for a new connection, and mitigates the effect of non
compactness by cheaply skipping over contiguous blocks of free entries.
See the "theory of operation" comment in flow.c for details.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>b
[sbrivio: additional ASSERT(flow_first_free <= FLOW_MAX - 2) to avoid
Coverity Scan false positive]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently, flows are only evern finally freed (and the table compacted)
from the deferred handlers. Some future ways we want to optimise managing
the flow table will rely on this, so enforce it: rather than having the
TCP code directly call flow_table_compact(), add a boolean return value to
the per-flow deferred handlers. If true, this indicates that the flow
code itself should free the flow.
This forces all freeing of flows to occur during the flow code's scan of
the table in flow_defer_handler() which opens possibilities for future
optimisations.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In general, the passt code is a bit haphazard about what's a true global
variable and what's in the quasi-global 'context structure'. The
flow_count field is one such example: it's in the context structure,
although it's really part of the same data structure as flowtab[], which
is a genuine global.
Move flow_count to be a regular global to match. For now it needs to be
public, rather than static, but we expect to be able to change that in
future.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently connected TCP sockets have the same epoll type, whether they're
for a "tap" connection or a spliced connection. This means that
tcp_sock_handler() has to do a secondary check on the type of the
connection to call the right function. We can avoid this by adding a new
epoll type and dispatching directly to the right thing.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
tcp_conn_destroy() and tcp_splice_destroy() are always called conditionally
on the connection being closed or closing. Move that logic into the
"destroy" functions themselves, renaming them tcp_flow_defer() and
tcp_splice_flow_defer().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
tcp_timer() scans the connection table, expiring "tap" connections and
calling tcp_splice_timer() for "splice" connections. tcp_splice_timer()
expires spliced connections and then does some other processing.
However, tcp_timer() is always called shortly after tcp_defer_handler()
(from post_handler()), which also scans the flow table expiring both tap
and spliced connections. So remove the redundant handling, and only do
the extra tcp_splice_timer() work from tcp_timer().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
flow_table.h, the lower level flow header relies on having the struct
definitions for every protocol specific flow type - so far that means
tcp_conn.h. It doesn't include it itself, so tcp_conn.h must be included
before flow_table.h.
That's ok for now, but as we use the flow table for more things,
flow_table.h will need the structs for all of them, which means the
protocol specific .c files would need to include tcp_conn.h _and_ the
equivalents for every other flow type before flow_table.h every time,
which is weird.
So, although we *mostly* lean towards the include style where .c files need
to handle the include dependencies, in this case it makes more sense to
have flow_table.h include all the protocol specific headers it needs.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Sufficiently recent cppcheck (I'm using 2.13.0) seems to have added another
warning for pointer variables which could be pointer to const but aren't.
Use this to make a bunch of variables const pointers where they previously
weren't for no particular reason.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We already define IN4ADDR_LOOPBACK_INIT to initialise a struct in_addr to
the loopback address without delving into its internals. However there are
some places we don't use it, and explicitly look at the internal structure
of struct in_addr, which we generally want to avoid. Use the define more
widely to avoid that.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently TCP uses the 'flow' epoll_ref field for both connected
sockets and timers, which consists of just the index of the relevant
flow (connection).
This is just fine for timers, for while it obviously works, it's
subtly incomplete for sockets on spliced connections. In that case we
want to know which side of the connection the event is occurring on as
well as which connection. At present, we deduce that information by
looking at the actual fd, and comparing it to the fds of the sockets
on each side.
When we use the flow table for more things, we expect more cases where
something will need to know a specific side of a specific flow for an
event, but nothing more.
Therefore add a new 'flowside' epoll_ref field, with exactly that
information. We use it for TCP connected sockets. This allows us to
directly know the side for spliced connections. For "tap"
connections, it's pretty meaningless, since the side is always the
socket side. It still makes logical sense though, and it may become
important for future flow table work.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently, we use 'int' values to represent the "side" of a connection,
which must always be 0 or 1. This turns out to be dangerous.
In some cases we're going to want to put the side into a 1-bit bitfield.
However, if that bitfield has type 'int', when we copy it out to a regular
'int' variable, it will be sign-extended and so have values 0 and -1,
instead of 0 and 1.
To avoid this, always use unsigned variables for the side.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
TCP uses three different epoll object types: one for connected sockets, one
for timers and one for listening sockets. Listening sockets really need
information that's specific to TCP, so need their own epoll_ref field.
Timers and connected sockets, however, only need the connection (flow)
they're associated with. As we expand the use of the flow table, we expect
that to be true for more epoll fds. So, rename the "TCP" epoll_ref field
to be a "flow" epoll_ref field that can be used both for TCP and for other
future cases.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Most of the messages logged by the TCP code (be they errors, debug or
trace messages) are related to a specific connection / flow. We're fairly
consistent about prefixing these with the type of connection and the
connection / flow index. However there are a few places where we put the
index later in the message or omit it entirely. The template with the
prefix is also a little bulky to carry around for every message,
particularly for spliced connections.
To help keep this consistent, introduce some helpers to log messages
linked to a specific flow. It takes the flow as a parameter and adds a
uniform prefix to each message. This makes things slightly neater now, but
more importantly will help keep formatting consistent as we add more things
to the flow table.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
tcp_table_compact() will move entries in the connection/flow table to keep
it compact when other entries are removed. The moved entries need not have
the same type as the flow removed, so it needs to be able to handle moving
any type of flow. Therefore, move it to flow.c rather than being
purportedly TCP specific.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Both tcp.c and tcp_splice.c define CONN_IDX() variants to find the index
of their connection structures in the connection table, now become the
unified flow table. We can easily combine these into a common helper.
While we're there, add some trickery for some additional type safety.
They also define their own CONN() versions, which aren't so easily combined
since they need to return different types, but we can have them use a
common helper.
In the process, we standardise on always using an unsigned type to store
the connection / flow index, which makes more sense. tcp.c's conn_at_idx()
remains for now, but we change its parameter to unsigned to match. That in
turn means we can remove a check for negative values from it.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We want to generalise "connection" tracking to things other than true TCP
connections. Continue implenenting this by renaming the TCP connection
table to the "flow table" and moving it to flow.c. The definitions are
split between flow.h and flow_table.h - we need this separation to avoid
circular dependencies: the definitions in flow.h will be needed by many
headers using the flow mechanism, but flow_table.h needs all those protocol
specific headers in order to define the full flow table entry.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently TCP connections use a 1-bit selector, 'spliced', to determine the
rest of the contents of the structure. We want to generalise the TCP
connection table to other types of flows in other protocols. Make a start
on this by replacing the tcp_conn_common structure with a new flow_common
structure with an enum rather than a simple boolean indicating the type of
flow.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Types size_t and ssize_t are not necessarily long, it depends on the
architecture.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
