mptcpd: add package

[dangowrt]

Maintainer: me
Compile tested: aarch64/cortex-a53
Run tested: -

Description:
Package the Multipath TCP daemon as well as the Embedded Linux Library (ell) it depends on.
Loosely based on prior work of @jeff277

Requires openwrt/openwrt#16786

[vortexilation]

Thanks but I have failed to see on how ell will take over some parts of libc related functionalities.
Is it automatically work on it's own ?.
Isn't it ell is 'only' a shared library?, or do we need application which also supports ell lib?.

[EDIT]
Looking again at the mptcpd Makefile, so it through mptcpd ?.

[dangowrt]

ell is simply a shared library providing additional functions as well as alternative implementations (under different names).
mptcpd and mptcpize uses some of the functions provided by ell.

[vortexilation]

getting error (x86_64, glibc, gcc 14.2.0) :

_dir/toolchain-x86_64_gcc-14.2.0_glibc/usr/include -I/home/user/works/openwrt/staging_dir/toolchain-x86_64_gcc-14.2.0_glibc/include -I/home/user/works/openwrt/staging_dir/target-x86_64_glibc_custom/usr/include -Wall -mtune=tigerlake -march=tigerlake -O3 -funsafe-math-optimizations -ffp-contract=fast -ftree-vectorize -fno-caller-saves -fno-plt -mtune=tigerlake -march=tigerlake -O3 -funsafe-math-optimizations -ffp-contract=fast -ftree-vectorize -fhonour-copts -fmacro-prefix-map=/home/user/works/openwrt/build_dir/target-x86_64_glibc_custom/mptcpd-0.12=mptcpd-0.12 -fstack-protector -D_FORTIFY_SOURCE=1 -O2 -fvisibility=hidden -Wextra -Werror -pedantic -fstack-protector-strong -c path_manager.c  -fPIC -DPIC -o .libs/libmptcpd_la-path_manager.o
In file included from path_manager.c:21:
/home/user/works/openwrt/staging_dir/target-x86_64_glibc_custom/usr/include/ell/genl.h: In function 'l_genl_attr_next':
/home/user/works/openwrt/staging_dir/target-x86_64_glibc_custom/usr/include/ell/genl.h:98:16: error: implicit declaration of function 'l_netlink_attr_next'; did you mean 'l_genl_attr_next'? [-Wimplicit-function-declaration]
   98 |         return l_netlink_attr_next((struct l_netlink_attr *) attr,
      |                ^~~~~~~~~~~~~~~~~~~
      |                l_genl_attr_next
/home/user/works/openwrt/staging_dir/target-x86_64_glibc_custom/usr/include/ell/genl.h: In function 'l_genl_attr_recurse':
/home/user/works/openwrt/staging_dir/target-x86_64_glibc_custom/usr/include/ell/genl.h:105:16: error: implicit declaration of function 'l_netlink_attr_recurse'; did you mean 'l_genl_attr_recurse'? [-Wimplicit-function-declaration]
  105 |         return l_netlink_attr_recurse((struct l_netlink_attr *) attr,
      |                ^~~~~~~~~~~~~~~~~~~~~~
      |                l_genl_attr_recurse
make[4]: *** [Makefile:597: libmptcpd_la-path_manager.lo] Error 1

[dangowrt]

Ok, thanks for testing with glibc. What does _custom stand for in your toolchain path?
I'm trying to reproduce this when buildong with glibc now...

[vortexilation]

It's only the folder named from CONFIG_BUILD_SUFFIX . Normally i am just testing around with glibc trunk/main/master version/2.41, seems faster by general on 2.41.

[EDIT]
Looks like someone already reported in before on here.

[vortexilation]

Based on the changelog, they have moved out the function declaration into other header file "netlink.h", the fix is simple :

diff -Naur a/ell/genl.h b/ell/genl.h
--- a/ell/genl.h
+++ b/ell/genl.h
@@ -11,6 +11,7 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
+#include "netlink.h"
 
 #ifdef __cplusplus
 extern "C" {

[Neustradamus]

@dangowrt: Nice PR, thanks!

[dangowrt]

@vortexilation I managed to reproduce the problem with GCC-14 and included your fix. Please also post your patch to the ell@lists.linux.dev mailing list for inclusion in future versions. See https://subspace.kernel.org/lists.linux.dev.html on how to join the mailing lists and post there. Thank you!

[matttbe]

Thank you for packaging ell and mptcpd (and enabling MPTCP in the kernel config!)

@vortexilation @dangowrt : Regarding the error with GCC 14, it looks like the issue comes from mptcpd, because it was including only the header files it needed. Even if that sounds like the proper thing to do, that's apparently not what is supposed to be done with ell. See multipath-tcp/mptcpd#309

In other words, no need to send a patch to ELL devs I suppose. (Or send a patch to have a proper documentation for ELL ;-) )