Let's replace usage of fputc_unlocked() and friends by __fsetlocking(f,
FSETLOCKING_BYCALLER). This turns off locking for the entire FILE*,
instead of doing individual per-call decision whether to use normal
calls or _unlocked() calls.
This has various benefits:
1. It's easier to read and easier not to forget
2. It's more comprehensive, as fprintf() and friends are covered too
(as these functions have no _unlocked() counterpart)
3. Philosophically, it's a bit more correct, because it's more a
property of the file handle really whether we ever pass it on to another
thread, not of the operations we then apply to it.
This patch reworks all pieces of codes that so far used fxyz_unlocked()
calls to use __fsetlocking() instead. It also reworks all places that
use open_memstream(), i.e. use stdio FILE* for string manipulations.
Note that this in some way a revert of 4b61c87511.
Using strlen() to declare a buffer results in a variable-length array,
even if the compiler likely optimizes it to be a compile time constant.
When building with -Wvla, certain versions of gcc complain about such
buffers. Compiling with -Wvla has the advantage of preventing variably
length array, which defeat static asserts that are implemented by
declaring an array of negative length.
So far I avoided adding license headers to meson files, but they are pretty
big and important and should carry license headers like everything else.
I added my own copyright, even though other people modified those files too.
But this is mostly symbolic, so I hope that's OK.
Implement DHCPv6 option to exchange information about the Fully
Qualified Domain Name (FQDN) according to RFC 4704.
The RFC 4704 describes two models of operations in section 3,
currently only the second model is supported (DHCPv6 server
updates both the AAAA and the PTR RRs).
The existing DHCP Section Options SendHostname and Hostname are
sent as FQDN to the server. According to section 4.2 sending
only parts of its FQDN is allowed.
Fixes#4682.
Technically DNS allows any ASCII character to be used in the
domain name. Also the DHCP specification for the FQDN option
(RFC 4702) does not put restriction on labels.
However, hostnames do have stricter requirements and typically
should only use characters from a-z (case insensitve), 0-9 and
minus.
Currently we require hostname/FQDN to be either a hostname or
a valid DNS name. Since dns_name_is_valid() allows any ASCII
characters this allows to specify hostnames which are typically
not valid.
Check hostname/FQDN more strictly and require them to pass both
tests. Specifically this requires the entire FQDN to be below 63.
When EmitDNS or EmitDomains is set, automatically look up values
for Router Advertisement DNS and DNS search domain options starting
with the values in the IPv6PrefixDelegationsection, if any. If none
are found, use the values set for the network, and as a last resort
try with the preferred upstream network.
The default DNS lifetime and therefore Router Advertisement interval
is added to the public sd_radv.h header as the DNS lifetime depends
on the maximum advertisement interval.
Let's rename all our functions that process IPv4 in_addr structures
in4_addr_xyz(), following the already establishing naming logic for
this.
Leave the in_addr_xyz() prefix for functions that process the IPv4/IPv6
in_addr_union union instead.
Add Router Advertisement DNS Search List option as specified
in RFC 8106. The search list option uses and identical option
header as the RDNSS option and therefore the option header
structure can be reused.
If systemd is compiled with IDNA support, internationalization
of the provided search domain is applied, after which the search
list is written in wire format into the DNSSL option.
An infiniband hardware address is 20 bytes, but sockaddr_ll.sll_addr is only 8
bytes. Explicitly ensure that sockaddr_union has enough space for infiniband
addresses, even if they run over sockaddr_ll and add a macro to compute the
proper size to pass to kernel.
As a follow-up for db3f45e2d2 let's do the
same for all other cases where we create a FILE* with local scope and
know that no other threads hence can have access to it.
For most cases this shouldn't change much really, but this should speed
dbus introspection and calender time formatting up a bit.
In normal operation this would trigger an assertion
when a DHCP server is configured every time the link goes up.
This change makes sd_dhcp_server_configure_pool idempotent
and stops the DHCP server when the link loses carrier.
In addition to this stopping the assertion being triggered,
this has the useful side-effect of allowing the link to be taken down
and then brought back up as a way to have it use DNS from an "upstream"
interface that got its DNS configuration via DHCP
after the downstream link was configured.
Test ICMPv6 Router Solicitation exponential backoff timer by
computing the minimum and maximum values according to RFC 7559,
Section 2 and the algorithm itself described in RFC 3315, Section
14. Reset the sd_ndisc timer to trigger after a zero second delay,
which causes the ndisc timeout to be triggered immediately once
the caller of the "sending" function returns to the main loop.
Move ICMPv6 Router Solicitation sending after timer computation so
that timers are already set up when the packet is being sent. This
makes it possible to create a test that inspects Router
Solicitation timer values when the Router Solicitation is sent out
on the network.
Instead of sending a fixed amount of Router Solicitiations, implement
the backoff algorithm proposed in RFC 7559. The backoff algorithm is
the same as used by DHCPv6.
Time out after 12s as specified in RFC 4861 in order not to delay
setting up a link for too long while sending Router Solicitations
in the background. Notice that after this change the callback will
receive a SD_NDISC_EVENT_TIMEOUT timeout event, and at a later point
when a router appears, a received Router Advertisment will cause the
callback to be called again with the SD_NDISC_EVENT_ROUTER event.
Let's downgrade the warning introduced by
955d99edc7 to debug, as we really
shouldn't log at more than debug level from library code.
(And while we are at it, print the MTU as the right (unsigned) type in
the format string.)
All those uses were correct, but I think it's better to be explicit.
Using implicit errno is too error prone, and with this change we can require
(in the sense of a style guideline) that the code is always specified.
Helpful query: git grep -n -P 'log_[^s][a-z]+\(.*%m'
Add tests for prefix creation, router variable setting and finally
verify that a Router Advertisement is properly formatted when sending.
Also check that there is a Router Advertisment with zero lifetime
when Router Advertisement sending is stopped.
Receive Router Solicitations and send a unicast Router Advertisment
in response. Refactor ICMPv6 packet handling code so that the common
ICMPv6 validation parts are reused between the existing router
discovery and the new functionality adding reception of Router
Solicitation messages.
Lennart Poettering
Thomas Haller
Zbigniew Jędrzejewski-Szmek
Daniel Lockyer
Shawn Landden
Stefan Agner
Yu Watanabe
Patrik Flykt
Florian Klink
Andreas Rammhold
juga0
bengal
hecke
Richard Maw
Matthias Greiner