Spotted by Coverity just recently. Not that it really matters as
MAXDNSRCH always appears to be defined as 1025, while a full domain
name can have up to 253 characters: it would be a bit pointless to
have a longer search domain.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
If a log file is configured, we would otherwise open a connection to
the system logger (if any), print any message that we might have
before we initialise the log file, and then keep that connection
around for no particular reason.
Call __openlog() as an alternative to the log file setup, instead.
This way, we might skip printing some messages during the
initialisation phase, but they're probably not really valuable to
have in a system log, and we're going to print them to standard
error anyway.
Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Now that we have logging functions embedding perror() functionality,
we can make _some_ calls more terse by using them. In many places,
the strerror() calls are still more convenient because, for example,
they are used in flow debugging functions, or because the return code
variable of interest is not 'errno'.
While at it, convert a few error messages from a scant perror style
to proper failure descriptions.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
perror() prints directly to standard error, but in many cases standard
error might be already closed, or we might want to skip logging, based
on configuration. Our logging functions provide all that.
While at it, make errors more descriptive, replacing some of the
existing basic perror-style messages.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
We currently use a LOG_EMERG log mask to represent the fact that we
don't know yet what the mask resulting from configuration should be,
before the command line is parsed.
However, we have the necessity of representing another phase as well,
that is, configuration is parsed but we didn't daemonise yet, or
we're not ready for operation yet. The next patch will add that
notion explicitly.
Mapping these cases to further log levels isn't really practical.
Introduce boolean log flags to represent them, instead of abusing
log priorities.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
The original behaviour of printing messages to standard error by
default when running from a non-interactive terminal was introduced
because the first KubeVirt integration draft used to start passt in
foreground and get messages via standard error.
For development purposes, the system logger was more convenient at
that point, and passt was running from interactive terminals only if
not started by the KubeVirt integration.
This behaviour was introduced by 84a62b79a2 ("passt: Also log to
stderr, don't fork to background if not interactive").
Later, I added command-line options in 1e49d194d0 ("passt, pasta:
Introduce command-line options and port re-mapping") and accidentally
reversed this condition, which wasn't a problem as --stderr could
force printing to standard error anyway (and it was used by KubeVirt).
Nowadays, the KubeVirt integration uses a log file (requested via
libvirt configuration), and the same applies for Podman if one
actually needs to look at runtime logs. There are no use cases left,
as far as I know, where passt runs in foreground in non-interactive
terminals.
Seize the chance to reintroduce some sanity here. If we fork to
background, standard error is closed, so --stderr is useless in that
case.
If we run in foreground, there's no harm in printing messages to
standard error, and that accidentally became the default behaviour
anyway, so --stderr is not needed in that case.
It would be needed for non-interactive terminals, but there are no
use cases, and if there were, let's log to standard error anyway:
the user can always redirect standard error to /dev/null if needed.
Before we're up and running, we need to print to standard error anyway
if something happens, otherwise we can't report failure to start in
any kind of usage, stand-alone or in integrations.
So, make --stderr do nothing, and deprecate it.
While at it, drop a left-over comment about --foreground being the
default only for interactive terminals, because it's not the case
anymore.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
If we don't run in foreground, we close standard error as we
daemonise, so it makes no sense to check if the controlling terminal
is an interactive terminal or if --force-stderr was given, to decide
if we want to log to standard error.
Make --force-stderr depend on --foreground.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
In multiple occasions, especially when passt(1) and pasta(1) are used
in integrations such as the one with Podman, the ability to override
earlier options on the command line with later one would have been
convenient.
Recently, to debug a number of issues happening with Podman, I would
have liked to ask users to share a debug log by passing --debug as
additional option, but pasta refuses --quiet (always passed by Podman)
and --debug at the same time.
On top of this, Podman lets users specify other pasta options in its
containers.conf(5) file, as well as on the command line.
The options from the configuration files are appended together with
the ones from the command line, which makes it impossible for users to
override options from the configuration file, if duplicated options
are refused, unless Podman takes care of sorting them, which is
clearly not sustainable.
For --debug and --trace, somebody took care of this on Podman side at:
https://github.com/containers/common/pull/2052
but this doesn't fix the issue with other options, and we'll have
anyway older versions of Podman around, too.
I think there's some value in telling users about duplicated or
conflicting options, because that might reveal issues in integrations
or accidental misconfigurations, but by now I'm fairly convinced that
the downsides outweigh this.
Drop checks about duplicate options and mutually exclusive ones. In
some cases, we need to also undo a couple of initialisations caused
by earlier options, but this looks like a simplification, overall.
Notable exception: --stderr still conflicts with --log-file, because
users might have the expectation that they don't actually conflict.
But they do conflict in the existing implementation, so it's safer
to make sure that the users notice that.
Suggested-by: Paul Holzinger <pholzing@redhat.com>
Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: Paul Holzinger <pholzing@redhat.com>
As we are going to introduce the MODE_VU that will act like
the mode MODE_PASST, compare to MODE_PASTA rather than to add
a comparison to MODE_VU when we check for MODE_PASST.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Functions and structures in lineread.c use plain int to record and report
the length of lines we receive. This means we truncate the result from
read(2) in some circumstances. Use ssize_t to avoid that.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In conf() we parse a MAC address in two places, for the --ns-mac-addr and
the -M options. As well as duplicating code, the logic for this parsing
has several bugs:
* The most serious is that if the given string is shorter than a MAC
address should be, we'll access past the end of it.
* We don't check the endptr supplied by strtol() which means we could
ignore certain erroneous contents
* We never check the separator characters between each octet
* We ignore certain sorts of garbage that follow the MAC address
Correct all these bugs in a new parse_mac() helper.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The message from usage() when given invalid options, or the -h / --help
option is currently printed by many calls to the info() function, also
used for runtime logging of informational messages.
That isn't useful: the usage message should always go to the terminal
(stdout or stderr), never syslog or a logfile. It should never be
filtered by priority. Really the only thing using the common logging
functions does is give more opportunities for something to go wrong.
Replace all the info() calls with direct fprintf() calls. This does mean
manually adding "\n" to each message. A little messy, but worth it for the
simplicity in other dimensions. While we're there make much heavier use
of single strings containing multiple lines of output text. That reduces
the number of fprintf calls, reducing visual clutter and making it easier
to see what the output will look like from the source.
Link: https://bugs.passt.top/show_bug.cgi?id=90
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
usage() does nothing but call print_usage() with EXIT_FAILURE as a
parameter. It's no more complex to just give that parameter at the single
call site. Eliminate it and rename print_usage() to just usage().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We have pidfile_fd now, pid_file_fd would be quite ugly.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Otherwise, if the user runs us as root, and gives us paths that are
only accessible by root, we'll fail to open them, which might in turn
encourage users to change permissions or ownerships: definitely a bad
idea in terms of security.
Reported-by: Minxi Hou <mhou@redhat.com>
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Acked-by: Richard W.M. Jones <rjones@redhat.com>
libguestfs tools have a good reason to run as root: if the guest image
is owned by root, it would be counterproductive to encourage users to
invoke them as non-root, as it would require changing permissions or
ownership of the image file.
And if they run as root, we'll start as root, too. Warn users we'll
switch to 'nobody', but don't tell them what to do.
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
In conf() we temporarily set the forwarding mode variables to 0 - an
invalid value, so that we can check later if they've been set by the
intervening logic. clang-tidy 18.1.1 in Fedora 40 now complains about
this. Satisfy it by giving an name in the enum to the 0 value.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
...simply resort to using locally-administered address (LAA) as
host-side source, instead.
Pick 02:00:00:00:00:00, to make it clear that we don't actually care
about that address, and also to match the 00 (Administratively
Assigned Identifier) quadrant of SLAP (RFC 8948).
Otherwise, pasta refuses to start if the template is a tun or
Wireguard interface.
Link: https://bugs.passt.top/show_bug.cgi?id=49
Link: https://github.com/containers/podman/issues/22320
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Since f919dc7a4b ("conf, netlink: Don't require a default route to
start"), if there is only one host interface with routes, we will pick that
as the template interface, even if there are no default routes for an IP
version. Unfortunately this selection had a serious flaw: in some cases
it would 'return' in the middle of an nl_foreach() loop, meaning we
wouldn't consume all the netlink responses for our query. This could cause
later netlink operations to fail as we read leftover responses from the
aborted query.
Rewrite the interface detection to avoid this problem. While we're there:
* Perform detection of both default and non-default routes in a single
pass, avoiding an ugly goto
* Give more detail on error and working but unusual paths about the
situation (no suitable interface, multiple possible candidates, etc.).
Fixes: f919dc7a4b ("conf, netlink: Don't require a default route to start")
Link: https://bugs.passt.top/show_bug.cgi?id=83
Link: https://github.com/containers/podman/issues/22052
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2270257
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Use info(), not warn() for somewhat expected cases where one
IP version has no default routes, or no routes at all]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
There might be isolated testing environments where default routes and
global connectivity are not needed, a single interface has all
non-loopback addresses and routes, and still passt and pasta are
expected to work.
In this case, it's pretty obvious what our upstream interface should
be, so go ahead and select the only interface with at least one
route, disabling DHCP and implying --no-map-gw as the documentation
already states.
If there are multiple interfaces with routes, though, refuse to start,
because at that point it's really not clear what we should do.
Reported-by: Martin Pitt <mpitt@redhat.com>
Link: https://github.com/containers/podman/issues/21896
Signed-off-by: Stefano brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
We might have read from resolv.conf, or from the command line, a
resolver that's reachable via loopback address, but that doesn't mean
we can offer that via DHCP, NDP or DHCPv6: warn if there are no
resolvers we can offer for a given IP version.
Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
...that is, call add_dns4() and add_dns6() instead of simply adding
those to the list of servers we advertise.
Most importantly, this will set the 'dns_host' field for the matching
IP version, so that, as mentioned in the man page, servers passed via
--dns are used for DNS mapping as well, if used in combination with
--dns-forward.
Reported-by: Paul Holzinger <pholzing@redhat.com>
Link: https://bugs.passt.top/show_bug.cgi?id=82
Fixes: 89678c5157 ("conf, udp: Introduce basic DNS forwarding")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Paul Holzinger <pholzing@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Starting from commit 3a2afde87d ("conf, udp: Drop mostly duplicated
dns_send arrays, rename related fields"), we won't add to c->ip4.dns
and c->ip6.dns nameservers that can't be used by the guest or
container, and we won't advertise them.
However, the fact that we don't advertise any nameserver doesn't mean
that we didn't find any, and we should warn only if we couldn't find
any.
This is particularly relevant in case both --dns-forward and
--no-map-gw are passed, and a single loopback address is listed in
/etc/resolv.conf: we'll forward queries directed to the address
specified by --dns-forward to the loopback address we found, we
won't advertise that address, so we shouldn't warn: this is a
perfectly legitimate usage.
Reported-by: Paul Holzinger <pholzing@redhat.com>
Link: https://github.com/containers/podman/issues/19213
Fixes: 3a2afde87d ("conf, udp: Drop mostly duplicated dns_send arrays, rename related fields")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Paul Holzinger <pholzing@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>
Currently port_fwd.[ch] contains helpers related to port forwarding,
particular automatic port forwarding. We're planning to allow much more
flexible sorts of forwarding, including both port translation and NAT based
on the flow table. This will subsume the existing port forwarding logic,
so rename port_fwd.[ch] to fwd.[ch] with matching updates to all the names
within.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
...instead of implying that by stating that there's no routable
interface for a given IP version. There might be interfaces with
non-default routes.
Suggested-by: Paul Holzinger <pholzing@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Paul Holzinger <pholzing@redhat.com>
--quiet is supposed to silence the "No routable interface" message but
it does not work because the log level was set long after conf_ip4/6()
was called which means it uses the default level which logs everything.
To address this move the log level logic directly after the option
parsing in conf().
Signed-off-by: Paul Holzinger <pholzing@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
...Podman users might get confused by the fact that if we can't
find a default route for a given IP version, we'll report that as a
warning message and possibly just before actual error messages.
However, a lack of routable interface for IPv4 or IPv6 can be a
normal circumstance: don't warn about it, just state that as
informational message, if those are displayed (they're not in
non-error paths in Podman, for example).
While at it, make it clear that we're disabling IPv4 or IPv6 if
there's no routable interface for the corresponding IP version.
Reported-by: Paul Holzinger <pholzing@redhat.com>
Link: https://github.com/containers/podman/pull/21563#issuecomment-1937024642
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
...or similar, that is, if only excluded ranges are given (implying
we'll forward any other available port). In that case, we'll usually
forward large sets of ports, and it might be inconvenient for the
user to skip excluding single ports that are already taken.
The existing behaviour, that is, exiting only if we fail to bind all
the ports for one given forwarding option, turns out to be
problematic for several aspects raised by Paul:
- Podman merges ranges anyway, so we might fail to bind all the ports
from a specific range given by the user, but we'll not fail anyway
because Podman merges it with another one where we succeed to bind
at least one port. At the same time, there should be no semantic
difference between multiple ranges given by a single option and
multiple ranges given as multiple options: it's unexpected and
not documented
- the user might actually rely on a given port to be forwarded to a
given container or a virtual machine, and if connections are
forwarded to an unrelated process, this might raise security
concerns
- given that we can try and fail to bind multiple ports before
exiting (in case we can't bind any), we don't have a specific error
code we can return to the user, so we don't give the user helpful
indication as to why we couldn't bind ports.
Exit as soon as we fail to create or bind a socket for a given
forwarded port, and report the actual error.
Keep the current behaviour, however, in case the user wants to
forward all the (available) ports for a given protocol, or all the
ports with excluded ranges only. There, it's more reasonable that
the user is expecting partial failures, and it's probably convenient
that we continue with the ports we could forward.
Update the manual page to reflect the new behaviour, and the old
behaviour too in the cases where we keep it.
Suggested-by: Paul Holzinger <pholzing@redhat.com>
Link: https://github.com/containers/podman/pull/21563#issuecomment-1937024642
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Paul Holzinger <pholzing@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
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>
udp uses the udp_tap_map, udp_splice_ns and udp_splice_init tables to keep
track of already opened sockets bound to specific ports. We need a way to
indicate entries where a socket hasn't been opened, but the code isn't
consistent if this is indicated by a 0 or a -1:
* udp_splice_sendfrom() and udp_tap_handler() assume that 0 indicates
an unopened socket
* udp_sock_init() fills in -1 for a failure to open a socket
* udp_timer_one() is somewhere in between, treating only strictly
positive fds as valid
-1 (or, at least, negative) is really the correct choice here, since 0 is
a theoretically valid fd value (if very unlikely in practice). Change to
use that consistently throughout.
The table does need to be initialised to all -1 values before any calls to
udp_sock_init() which can happen from conf_ports(). Because C doesn't make
it easy to statically initialise non zero values in large tables, this does
require a somewhat awkward call to initialise the table from conf(). This
is the best approach I could see for the short term, with any luck it will
go away at some point when those socket tables are replaced by a unified
flow table.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
logmsg() takes printf like arguments, but because it's not a built in, the
compiler won't generate warnings if the format string and parameters don't
match. Enable those by using the format attribute.
Strictly speaking this is a gcc extension, but I believe it is also
supported by some other common compilers. We already use some other
attributes in various places. For now, just use it and we can worry about
compilers that don't support it if it comes up.
This exposes some warnings from existing callers, both in gcc and in
clang-tidy:
- Some are straight out bugs, which we correct
- It's occasionally useful to invoke the logging functions with an empty
string, which gcc objects to, so disable that specific warning in the
Makefile
- Strictly speaking the C standard requires that the parameter for a %p
be a (void *), not some other pointer type. That's only likely to cause
problems in practice on weird architectures with different sized
representations for pointers to different types. Nonetheless add the
casts to make it happy.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The implementation of scanning /proc files to do automatic port forwarding
is a bit awkwardly split between procfs_scan_listen() in util.c,
get_bound_ports() and related functions in conf.c and the initial setup
code in conf().
Consolidate all of this into port_fwd.h, which already has some related
definitions, and a new port_fwd.c.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Initialisation of the forwarding mode variables is complicated a bit by the
fact that we have different defaults for passt and pasta modes. This leads
to some debateably duplicated code between those two cases.
More significantly, however, currently the final setting of the mode
variable is interleaved with the code to actually start automatic scanning
when that's selected. This essentially mingles "policy" code (setting the
default mode), with implementation code (making that happen). That's a bit
inflexible if we want to change policies in future.
Disentangle these two pieces, and use a slightly different construction to
make things briefer as well.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In a couple of places in conf(), we use a local 'fwd' variable to reference
one of our forwarding tables. The value depends on which command line
option we're currently looking at, and is initialized rather cryptically
from an assignment side-effect within the if condition checking that
option.
Newer versions of cppcheck complain about this assignment being an always
true condition, but in any case it's both clearer and slightly shorter to
use separate if branches for the two cases and set the forwarding parameter
more directly.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Newer versions of cppcheck (as of 2.12.0, at least) added a warning for
pointers which could be declared to point at const data, but aren't.
Based on that, make many pointers throughout the codebase const.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We give a fatal error if the port ranges from any port forwarding
specifiers overlap. This occurs even if those port ranges are specifically
bound to different addresses, so there's not really any overlap.
Right now, we can't 100% handle this case correctly, because our data
structures don't have a way to represent per-address forwarding. However,
there are a number of cases that will actually work just fine: e.g. mapping
the same port to the same port on two different addresses (say :: and
127.0.0.1).
We have long term plans to fix this properly, but that is still some time
away. For the time being, demote this error to a warning so that the cases
that already work will be allowed.
Link: https://bugs.passt.top/show_bug.cgi?id=56
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently if we receive any netlink errors while discovering network
configuration from the host, we'll just ignore it and carry on. This
might lead to cryptic error messages later on, or even silent
misconfiguration.
We now have the mechanisms to detect errors from get/dump netlink
operations. Propgate these errors up to the callers and report them usefully.
Link: https://bugs.passt.top/show_bug.cgi?id=60
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
All the netlink operations currently implicitly use one of the two global
netlink sockets, sometimes depending on an 'ns' parameter. Change them
all to explicitly take the socket to use (or two sockets to use in the case
of the *_dup() functions). As well as making these functions strictly more
general, it makes the callers easier to follow because we're passing a
socket variable with a name rather than an unexplained '0' or '1' for the
ns parameter.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Minor formatting changes in pasta_ns_conf()]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
nl_route() can perform 3 quite different operations based on the 'op'
parameter. Split this into separate functions for each one. This requires
more lines of code, but makes the internal logic of each operation much
easier to follow.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
nl_addr() can perform three quite different operations based on the 'op'
parameter, each of which uses a different subset of the parameters. Split
them up into a function for each operation. This does use more lines of
code, but the overlap wasn't that great, and the separated logic is much
easier to follow.
It's also clearer in the callers what we expect the netlink operations to
do, and what information it uses.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Minor formatting fixes in pasta_ns_conf()]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
nl_link() performs a number of functions: it can bring links up, set MAC
address and MTU and also retrieve the existing MAC. This makes for a small
number of lines of code, but high conceptual complexity: it's quite hard
to follow what's going on both in nl_link() itself and it's also not very
obvious which function its callers are intending to use.
Clarify this, by splitting nl_link() into nl_link_up(), nl_link_set_mac(),
and nl_link_get_mac(). The first brings up a link, optionally setting the
MTU, the others get or set the MAC address.
This fixes an arguable bug in pasta_ns_conf(): it looks as though that was
intended to retrieve the guest MAC whether or not c->pasta_conf_ns is set.
However, it only actually does so in the !c->pasta_conf_ns case: the fact
that we set up==1 means we would only ever set, never get, the MAC in the
nl_link() call in the other path. We get away with this because the MAC
will quickly be discovered once we receive packets on the tap interface.
Still, it's neater to always get the MAC address here.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
ns_enter() returns an integer... but it's always zero. If we actually fail
the function doesn't return. Therefore it makes more sense for this to be
a function returning void, and we can remove the cases where we pointlessly
checked its return value.
In addition ns_enter() is usually called from an ephemeral thread created
by NS_CALL(). That means that the exit(EXIT_FAILURE) there usually won't
be reported (since NS_CALL() doesn't wait() for the thread). So, use die()
instead to print out some information in the unlikely event that our
setns() here does fail.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
When interface names are specified in forwarding specs, we need to check
the length of the given interface name against the limit of IFNAMSIZ - 1
(15) characters. However, we managed to have 3 separate off-by-one errors
here meaning we only accepted interface names up to 12 characters.
1. At the point of the check 'ifname' was still on the '%' character, not
the first character of the name, meaning we overestimated the length by
one
2. At the point of the check 'spec' had been advanced one character past
the '/' which terminates the interface name, meaning we overestimated
the length by another one
3. We checked if the (miscalculated) length was >= IFNAMSIZ - 1, that is
>= 15, whereas lengths equal to 15 should be accepted.
Correct all 3 errors.
Link: https://bugs.passt.top/show_bug.cgi?id=61
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Network interface names must fit in a buffer of IFNAMSIZ bytes, including
the terminating \0. IFNAMSIZ is 16 on Linux, so interface names can be
up to (and including) 15 characters long.
We validate this for the -I option, but we have an off by one error. We
pass (IFNAMSIZ - 1) as the buffer size to snprintf(), but that buffer size
already includes the terminating \0, so this actually truncates the value
to 14 characters. The return value returned from snprintf() however, is
the number of characters that would have been printed *excluding* the
terminating \0, so by comparing it >= IFNAMSIZ - 1 we are giving an error
on names >= 15 characters rather than strictly > 15 characters.
Link: https://bugs.passt.top/show_bug.cgi?id=61
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
While --no-copy-addrs and --no-copy-routes only make sense with
--config-net, and they are implied on -g and -a, respectively, that
doesn't mean we should refuse -a or -g without --config-net: they are
still relevant for a number of things (including DHCP/DHCPv6/NDP
configuration).
Reported-by: Gianluca Stivan <me@yawnt.com>
Fixes: cc9d16758b ("conf, pasta: With --config-net, copy all addresses by default")
Fixes: da54641f14 ("conf, pasta: With --config-net, copy all routes by default")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
I wrote it in commit message and man page, but not in conf()...
Note that -g/--gateway correctly implies --no-copy-routes already.
This fixes Podman's tests:
podman networking with pasta(1) - IPv4 address assignment
podman networking with pasta(1) - IPv4 default route assignment
where we pass -a and -g to assign an address and a default gateway
that's compatible with it, but -a doesn't disable the copy of
addresses, so we ignore -a, and the default gateway is incompatible
with the addresses we copy -- hence no routes in the container.
Link: https://github.com/containers/podman/pull/18612
Fixes: cc9d16758b ("conf, pasta: With --config-net, copy all addresses by default")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Erik suggests that this makes it easier to grep for options, and with
--help we're anyway printing usage information as expected, not as
part of an error report.
While at it: on -h, we should exit with 0.
Reported-by: Erik Sjölund <erik.sjolund@gmail.com>
Link: https://bugs.passt.top/show_bug.cgi?id=52
Link: https://bugs.passt.top/show_bug.cgi?id=53
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
a7359f0948 ("conf: Don't exit if sourced default route has no gateway")
was supposed to allow passt/pasta to run even if given a template interface
which has no default gateway. However a mistake in the patch means it
still requires the gateway, but doesn't require a global address for the
guest which we really do need.
This is one part (but not the only part) of the problem seen in
https://bugs.passt.top/show_bug.cgi?id=50.
Reported-by: Justin Jereza <justinjereza@gmail.com>
Fixes: a7359f0948 ("conf: Don't exit if sourced default route has no gateway")
Link: https://bugs.passt.top/show_bug.cgi?id=50
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
