Then make dhcp_packet_append_ip_headers() just a wrapper of the new
function. Currently, the wrapper is inefficient, but will be removed in
a later commit.
The commit 6d7cb9a6b8 fixes the assignment
of the these options when specified through SendOption=. However, it
breaks when specified through UserClass= or SendVendorOption=.
When UserClass= or SendVendorOption= is specified, the option length is
calculated from the sd_dhcp_client.user_class or .vendor_options. Hence,
we can use 0 for the length in that case.
Follow-up for 6d7cb9a6b8.
This adds a new `Hostname=` option to the [DHCPServerStaticLease]
section in .network files, allowing an administrator to assign a
specific hostname to a client receiving a static lease.
We automatically select the correct DHCP option to use based on the
format of the provided string:
- Single DNS labels are sent as Option 12.
- Names with multiple DNS labels are sent as Option 81 in wire format.
Fixes: #39634
Implements DHCP option 15 (Domain Name) for systemd-networkd's DHCP
server, allowing administrators to configure the DNS default domain that
clients should use.
This addresses the feature request in issue #37077, where users needed
to manually configure domain names using
SendOption=15:string:example.com as a workaround.
This adds two new configuration options to the [DHCPServer] section:
- EmitDomain= (boolean): whether to send domain name to clients
- Domain= (string): the domain name to send (e.g., "example.com")
Example configuration:
[DHCPServer] EmitDomain=yes Domain=example.com
This eliminates the need for manual workarounds using
SendOption=15:string:...
Fixes#37077
For libsystemd's headers, the changes made depend on whether the
header is installed or not. For installed headers, the only change
made is that commonly included headers were moved to _sd-common.h.
For these headers, there should be no noticeable change in behavior
when including them. For non-installed headers, includes were replaced
with forward declarations where possible as usual.
Split out of #37344.
I do not think this is necessary, but all other places in
libsystemd-network we clear buffer before receive. Without this,
Coverity warns about use-of-uninitialized-values.
Let's silence Coverity.
Closes CID#1469721.
Currently, the received hostname is not used for assigning an address to
the host, or options in the subsequent reply message. But, the parsed
hostname is exposed through DBus, and possibly Varlink in the future.
Let's ignore spurious hostname.
Currently, networkd does not change pool size dynamically, so this
should not change behavior. But if networkd does that, then forgetting
leases causes that an address still used by a client may be assigned to
another host.
- Even if we found a matching static lease, check if there is no
conflicting lease.
- Accept an address request that is different from the previous one.
- Also return NAK if the server address is requested.
Those functions take a pointer to a timestamp and return a timestamp pointer,
so the reader would be justified to think that those are just getters. Rename
them to avoid confusion.
It seems that RFC does not say anything about the timestamp of lease
we should use: time that the client sent a request or received a reply.
In DHCPv6 client and NDisc, we use a timestamp that we receive a packet,
rather than we sent something. So, let's consistently use the same
logic for DHCPv4 client.
By using the logic, we will hopefully not forget to set timestamp again,
which is fixed by 089362976c.
This is preparation for #28891, which adds a bunch more helpers around
"struct iovec", at which point this really deserves its own .c/.h file.
The idea is that we sooner or later can consider "struct iovec" as an
entirely generic mechanism to reference some binary blob, and is the
go-to type for this purpose whenever we need one.
DHCP clients often send their own hostname in option 12. It can be useful
to store it with the lease so it can be shown to a human to easily identify
which lease belongs to which device.
RFC: https://www.rfc-editor.org/rfc/rfc2132#section-3.14
If we fail any allocation prior adding the lease to the server lease
hashmap.
==2103==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 128 byte(s) in 2 object(s) allocated from:
#0 0x4a203e in __interceptor_calloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:77:3
#1 0x4f6341 in calloc (/build/fuzz-dhcp-server+0x4f6341)
#2 0x4ec818 in add_lease /work/build/../../src/systemd/src/libsystemd-network/fuzz-dhcp-server.c:26:9
#3 0x4ec2bf in LLVMFuzzerTestOneInput /work/build/../../src/systemd/src/libsystemd-network/fuzz-dhcp-server.c:75:9
#4 0x4f68a8 in NaloFuzzerTestOneInput (/build/fuzz-dhcp-server+0x4f68a8)
#5 0x5158b3 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:611:15
#6 0x51509a in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool, bool*) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:514:3
#7 0x516769 in fuzzer::Fuzzer::MutateAndTestOne() /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:757:19
#8 0x517435 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, std::__Fuzzer::allocator<fuzzer::SizedFile> >&) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:895:5
#9 0x50679f in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:912:6
#10 0x507068 in LLVMFuzzerRunDriver /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:925:10
#11 0x4f6b25 in main (/build/fuzz-dhcp-server+0x4f6b25)
#12 0x7f16084e3082 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24082) (BuildId: 1878e6b475720c7c51969e69ab2d276fae6d1dee)
DEDUP_TOKEN: __interceptor_calloc--calloc--add_lease
SUMMARY: AddressSanitizer: 128 byte(s) leaked in 2 allocation(s).
Found by Nallocufzz.
From RFC 2131 section 4.3.1 (https://www.rfc-editor.org/rfc/rfc2131#section-4.3.1):
----
The server MUST return to the client:
- Parameters requested by the client, according to the following rules:
-- IF the server has been explicitly configured with a default
value for the parameter, the server MUST include that value
in an appropriate option in the 'option' field,
----
The sentence is not only for ACK, but for all (positive) responses, that
is DHCPOFFER and DHCPACK.
Fixes#27471.
DHCP static leases are looked up by the client identifier as send by
the client, while configured based on MAC. As RFC 2131 states the client
identifier is an opaque key and must not be interpreted by the server
this means that DHCP clients can (/will) also use a client identifier
which is not a MAC address. One of these clients actually is
systemd-networkd which uses an RFC 4361 by default to generate the
client identifier. For these kind of DHCP clients static leases thus
don't work because of this mismatch between configuring a MAC address
but the server matching based on client identifier. This adds a fallback
to try to look up a configured static lease based on the "chaddr" of the
DHCP message as this will always contain the MAC address of the client.
Fixes#21368
-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.
Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state
Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.
In some places, initialization is dropped if unnecessary.
Yu Watanabe
Lennart Poettering
Michael Vogt
Lennart Poettering
Chris Down
Govind Venugopal
Colin Foster
Daan De Meyer
Mike Yuan
Zbigniew Jędrzejewski-Szmek
Susant SahaniandYu Watanabe
Rene Hollander
Frantisek Sumsal
Robert Meijers
David Tardon