see linux commit 7fd3253a7de6a317a0683f83739479fb880bffc8 net: Introduce preferred busy-polling linux commit 7c951cafc0cb2e575f1d58677b95ac387ac0a5bd net: Add SO_BUSY_POLL_BUDGET socket option
see linux commit 99f3a064bc2e4bd5fe50218646c5be342f2ad18c bpf: net: Add SO_DETACH_REUSEPORT_BPF
now that all 32-bit archs have 64-bit time types, the values for the time-related socket option macros can be treated as universal for 32-bit archs. the sys/socket.h mechanism for this predates arch/generic and is instead in the top-level header. x32, which does not use the new time64 values of the macros, already has its own overrides, so this commit does not affect it.
these structures can now be defined generically in terms of endianness and long size. previously, the 32-bit archs all shared a common definition from the generic bits header, and each 64-bit arch had to repeat the 64-bit version, with endian conditionals if the arch had variants of each endianness. I would prefer getting rid of the preprocessor conditionals for padding and instead using unnamed bitfield members, like commit 9b2921bea1d5017832e1b45d1fd64220047a9802 did for struct timespec. however, at present sendmsg, recvmsg, and recvmmsg need access to the padding members by name to zero them. this could perhaps be cleaned up in the future.
SO_RCVTIMEO and SO_SNDTIMEO already were, but only in aggregate with SO_DEBUG and all of the other low/traditional options that varied per arch. SO_TIMESTAMP* are newly overridable. the two groups have to be done separately since mips64 and powerpc64 will override the former but not the latter. at some point this should be cleaned up to use bits headers more idiomatically.
a _REDIR_TIME64 macro is introduced, which the arch's alltypes.h is expected to define, to control redirection of symbol names for interfaces that involve time_t and derived types. this ensures that object files will only be linked to libc interfaces matching the ABI whose headers they were compiled against. along with time32 compat shims, which will be introduced separately, the redirection also makes it possible for a single libc (static or shared) to be used with object files produced with either the old (32-bit time_t) headers or the new ones after 64-bit time_t switchover takes place. mixing of such object files (or shared libraries) in the same program will also be possible, but must be done with care; ABI between libc and a consumer of the libc interfaces is guaranteed to match by the the symbol name redirection, but pairwise ABI between consumers of libc that define interfaces between each other in terms of time_t is not guaranteed to match. this change adds a dependency on an additional "GNU C" feature to the public headers for existing 32-bit archs, which is generally undesirable; however, the feature is one which glibc has depended on for a long time, and thus which any viable alternative compiler is going to need to provide. 64-bit archs are not affected, nor will future 32-bit archs be, regardless of whether they are "new" on the kernel side (e.g. riscv32) or just newly-added (e.g. a new sparc or xtensa port). the same applies to newly-added ABIs for existing machine-level archs.
SO_BINDTOIFINDEX behaves similar to SO_BINDTODEVICE, but takes a network interface index as argument, rather than the network interface name. see linux commit f5dd3d0c9638a9d9a02b5964c4ad636f06cf7e2c net: introduce SO_BINDTOIFINDEX sockopt
added in linux commit 80b14dee2bea128928537d61c333f24cb8cbb62f
new address family and related macros were added in linux commit 68e8b849b221b37a78a110a0307717d45e3593a0
adapted from patch by Matthias Schiffer.