Otherwise, other applications cannot bind to port 0.0.0.0:68 at the same time.
This is for example what dhclient wants to do. So even when running
dhclient on another, unrelated interface, it would fail to bind the UDP
socket and quit.
Note that also systemd-networkd's DHCPv4 client sets this socket option.
Presumably for the same reasons.
Signed-off-by: Thomas Haller <thaller@redhat.com>
https://github.com/nettools/n-dhcp4/pull/12
In some cases it is useful to have the library log what it is doing
for debugging purposes; add a simple API that allows setting a
syslog-style logging level and specifying a logging function.
https://github.com/nettools/n-dhcp4/pull/8
Currently in any of the BOUND, RENEWING and REBINDING states the probe
checks the expiration of T1, T2 and lifetime. This is not correct
because, for example, if the timer fires in the RENEWING state, the
probe must not transition to RENEWING again (i.e. check again that
now >= T1). Note that there is no guarantee that the timer triggers
exactly once for T1, T2 and lifetime expirations because the timer is
also used for the retransmission logic in NDhcp4CConnection.
Therefore, add some checks to ensure that only correct transitions are
allowed.
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/merge_requests/341https://bugzilla.redhat.com/show_bug.cgi?id=1773456
The API already had n_dhcp4_client_lease_get_lifetime(), which is the CLOCK_BOOTTIME
when the lease expires (or ((uint64_t)-1)). But it might be interesting to
know the actual lease duration and when the lease was received (and the
time started to count).
Expose an API for that. With this, one can also calculate the original, exact lease
lifetime, by subtracting n_dhcp4_client_lease_get_basetime() from n_dhcp4_client_lease_get_lifetime(),
while taking care of ((uint64_t)-1).
First of all, from the naming of n_dhcp4_incoming_query_u32() it is
confusing to coerce 0xFFFFFFFF to zero. It should just return the
plain value.
Also note that n_dhcp4_incoming_query_u32() only has three callers:
n_dhcp4_incoming_query_lifetime(), n_dhcp4_incoming_query_t1() and
n_dhcp4_incoming_query_t2().
Looking further, those three functions only have one caller:
n_dhcp4_incoming_get_timeouts(). Note how the code there already tries
to handle UINT32_MAX and interprets it as infinity (UINT64_MAX).
But as it was, UINT32_MAX never actually was returned.
It seems that RFC [1] does not specially define the meanings of
0xFFFFFFFF and 0. It sounds reasonable to assume that 0 just means
0 lifetime, and 0xFFFFFFFF means infinity. On the other hand, compare
this to systemd's code [2], which coerces 0 to 1. This does not seem
right to me though. Note how systemd returns 0xFFFFFFFF as-is.
Drop the special handling of 0xFFFFFFFF from n_dhcp4_incoming_query_u32().
It now just returns the plain value and it's up to n_dhcp4_incoming_get_timeouts()
to make sense of that. This will fix behavior, so that 0xFFFFFFFF will be
reported as infinity, and not as zero.
[1] https://tools.ietf.org/html/rfc2132#section-9.2
[2] 68c2b5ddb1/src/libsystemd-network/sd-dhcp-lease.c (L553)
It is error prone when a function consumes an input only in certain
cases (and telling the caller via the return code). At least in these
cases, the message is never used afterwards, and we can always pass
it on.
When we build n-dhcp4 for NetworkManager we get a compiler warning.
This can also be reproduced by building n-dhcp4 alone:
$ CFLAGS='-Werror=declaration-after-statement' meson build && ninja -C build
...
[36/47] Compiling C object 'src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o'.
FAILED: src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o
ccache cc -Isrc/25a6634@@ndhcp4-private@sta -Isrc -I../src -Isubprojects/c-list/src -I../subprojects/c-list/src -Isubprojects/c-siphash/src -I../subprojects/c-siphash/src -Isubprojects/c-stdaux/src -I../subprojects/c-stdaux/src -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=c11 -g -D_GNU_SOURCE -Werror=declaration-after-statement -fPIC -fvisibility=hidden -fno-common -MD -MQ 'src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o' -MF 'src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o.d' -o 'src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o' -c ../src/n-dhcp4-outgoing.c
../src/n-dhcp4-outgoing.c: In function ‘n_dhcp4_outgoing_new’:
../src/n-dhcp4-outgoing.c:63:9: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
63 | static_assert(N_DHCP4_NETWORK_IP_MINIMUM_MAX_SIZE >= N_DHCP4_OUTGOING_MAX_PHDR +
| ^~~~~~~~~~~~~
(cherry picked from commit 9e7ca3e091)
The probe takes a reference to the current lease and so it must
release it upon destruction.
Signed-off-by: Beniamino Galvani <bgalvani@redhat.com>
https://github.com/nettools/n-dhcp4/pull/1
In particular, avoid including linux/netdevice.h from headers. This is
not a problem on newer distros, but required for CentOS 7.6.
Signed-off-by: Tom Gundersen <teg@jklm.no>
