This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
kernel >= 4.5 (with commit 32bc201e19) supports
RTA_EXPIRES netlink attribute to set router lifetime. This simply detect
the kernel version (>=4.5) and set the lifetime properly, fallback to
expiring route in userspace for kernel that doesnt support it.
Signed-off-by: Daniel Dao <dqminh89@gmail.com>
This adds some paranoia code that moves some of the fds we allocate for
longer periods of times to fds > 2 if they are allocated below this
boundary. This is a paranoid safety thing, in order to avoid that
external code might end up erroneously use our fds under the assumption
they were valid stdin/stdout/stderr. Think: some app closes
stdin/stdout/stderr and then invokes 'fprintf(stderr, …' which causes
writes on our fds.
This both adds the helper to do the moving as well as ports over a
number of users to this new logic. Since we don't want to litter all our
code with invocations of this I tried to strictly focus on fds we keep
open for long periods of times only and only in code that is frequently
loaded into foreign programs (under the assumptions that in our own
codebase we are smart enough to always keep stdin/stdout/stderr
allocated to avoid this pitfall). Specifically this means all code used
by NSS and our sd-xyz API:
1. our logging APIs
2. sd-event
3. sd-bus
4. sd-resolve
5. sd-netlink
This changed was inspired by this:
https://github.com/systemd/systemd/issues/8075#issuecomment-363689755
This shows that apparently IRL there are programs that do close
stdin/stdout/stderr, and we should accomodate for that.
Note that this won't fix any bugs, this just makes sure that buggy
programs are less likely to interfere with out own code.
Some routes (such as those using "nexthop") don't have an RTA_OIF
attribute. We need to handle that gracefully, by simply ignoring the
route.
Fixes: #7854
log.h really should only include the bare minimum of other headers, as
it is really pulled into pretty much everything else and already in
itself one of the most basic pieces of code we have.
Let's hence drop inclusion of:
1. sd-id128.h because it's entirely unneeded in current log.h
2. errno.h, dito.
3. sys/signalfd.h which we can replace by a simple struct forward
declaration
4. process-util.h which was needed for getpid_cached() which we now hide
in a funciton log_emergency_level() instead, which nicely abstracts
the details away.
5. sys/socket.h which was needed for struct iovec, but a simple struct
forward declaration suffices for that too.
Ultimately this actually makes our source tree larger (since users of
the functionality above must now include it themselves, log.h won't do
that for them), but I think it helps to untangle our web of includes a
tiny bit.
(Background: I'd like to isolate the generic bits of src/basic/ enough
so that we can do a git submodule import into casync for it)
Let's include netinet/in.h instead of linux/in6.h, as the former is the
official libc location for these definitions, and the latter is a
linux-specific version that conflicts.
This hopefully makes systemd compile on current Semaphore again.
This takes e410b07d2a into consideration,
but makes us use glibc rather than kernel headers.
While we are at it, let's also sort our #include lines. Since kernel
headers are notoriously crappy we won't strictly order them globally,
but first include non-kernel headers in a sorted way, and then include
kernel headers in a somewhat sorted way (i.e. generic stuff first and
somewhat alphabetical, and specific stuff last)
This also adds the ability to incorporate arrays into netlink messages
and to determine when a netlink message is too big, used by some generic
netlink protocols.
Similar to the virtual ethernet driver veth, vxcan implements a
local CAN traffic tunnel between two virtual CAN network devices.
When creating a vxcan, two vxcan devices are created as pair
When one end receives the packet it appears on its pair and vice
versa. The vxcan can be used for cross namespace communication.
Routing Policy rule manipulates rules in the routing policy database control the
route selection algorithm.
This work supports to configure Rule
```
[RoutingPolicyRule]
TypeOfService=0x08
Table=7
From= 192.168.100.18
```
```
ip rule show
0: from all lookup local
0: from 192.168.100.18 tos 0x08 lookup 7
```
V2 changes:
1. Added logic to handle duplicate rules.
2. If rules are changed or deleted and networkd restarted
then those are deleted when networkd restarts next time
V3:
1. Add parse_fwmark_fwmask
This moves pretty much all uses of getpid() over to getpid_raw(). I
didn't specifically check whether the optimization is worth it for each
replacement, but in order to keep things simple and systematic I
switched over everything at once.
If our netlink input buffer overruns the kernel will send us ENOBUFS on
the next recvmsg(). Don't consider this a complete failure resulting in
closing of the netlink socket. Instead, simply continue (after debug
logging).
Of course, ideally we'd have a better strategy for this, and would have
a way to resync if this happens (as well as a scheme for cancelling all
ongoing asynchronous transactions), but for now let's at least not choke
fatally, and simply accept that we lost some messages and continue.
Note that if we lose messages when synchronously waiting for an
operation to complete, we'll still propagate the ENOBUFS up, to make the
individual transaction fail.
See: #5398
(This bug does not properly fix the issue, hence we should leave the bug
open.)
We don't have plural in the name of any other -util files and this
inconsistency trips me up every time I try to type this file name
from memory. "formats-util" is even hard to pronounce.
On larger systems we might very well see messages with thousands of parts.
When we free them, we must avoid recursing into each part, otherwise we
very likely get stack overflows.
Fix sd_netlink_message_unref() to use an iterative approach rather than
recursion (also avoid tail-recursion in case it is not optimized by the
compiler).
Introduce
1. sd_rtnl_message_route_set_table to set table ID
2. sd_rtnl_message_route_set_family to set family
Both required to configure route properties.
* sd-netlink: permit RTM_DELLINK messages with no ifindex
This is useful for removing network interfaces by name.
* nspawn: explicitly remove veth links we created after use
Sometimes the kernel keeps veth links pinned after the namespace they have been
joined to died. Let's hence explicitly remove veth links after use.
Fixes: #2173
Throughout the tree there's spurious use of spaces separating ++ and --
operators from their respective operands. Make ++ and -- operator
consistent with the majority of existing uses; discard the spaces.
