Kuniyuki Iwashima d5e4ddaeb6 bpf: Support socket migration by eBPF. ... This patch introduces a new bpf_attach_type for BPF_PROG_TYPE_SK_REUSEPORT to check if the attached eBPF program is capable of migrating sockets. When the eBPF program is attached, we run it for socket migration if the expected_attach_type is BPF_SK_REUSEPORT_SELECT_OR_MIGRATE or net.ipv4.tcp_migrate_req is enabled. Currently, the expected_attach_type is not enforced for the BPF_PROG_TYPE_SK_REUSEPORT type of program. Thus, this commit follows the earlier idea in the commit aac3fc320d ("bpf: Post-hooks for sys_bind") to fix up the zero expected_attach_type in bpf_prog_load_fixup_attach_type(). Moreover, this patch adds a new field (migrating_sk) to sk_reuseport_md to select a new listener based on the child socket. migrating_sk varies depending on if it is migrating a request in the accept queue or during 3WHS. - accept_queue : sock (ESTABLISHED/SYN_RECV) - 3WHS : request_sock (NEW_SYN_RECV) In the eBPF program, we can select a new listener by BPF_FUNC_sk_select_reuseport(). Also, we can cancel migration by returning SK_DROP. This feature is useful when listeners have different settings at the socket API level or when we want to free resources as soon as possible. - SK_PASS with selected_sk, select it as a new listener - SK_PASS with selected_sk NULL, fallbacks to the random selection - SK_DROP, cancel the migration. There is a noteworthy point. We select a listening socket in three places, but we do not have struct skb at closing a listener or retransmitting a SYN+ACK. On the other hand, some helper functions do not expect skb is NULL (e.g. skb_header_pointer() in BPF_FUNC_skb_load_bytes(), skb_tail_pointer() in BPF_FUNC_skb_load_bytes_relative()). So we allocate an empty skb temporarily before running the eBPF program. Suggested-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/netdev/20201123003828.xjpjdtk4ygl6tg6h@kafai-mbp.dhcp.thefacebook.com/ Link: https://lore.kernel.org/netdev/20201203042402.6cskdlit5f3mw4ru@kafai-mbp.dhcp.thefacebook.com/ Link: https://lore.kernel.org/netdev/20201209030903.hhow5r53l6fmozjn@kafai-mbp.dhcp.thefacebook.com/ Link: https://lore.kernel.org/bpf/20210612123224.12525-10-kuniyu@amazon.co.jp		2021-06-15 18:01:06 +02:00
..
acpi	…
asm-generic	mm: remove xlate_dev_kmem_ptr()	2021-05-07 00:26:34 -07:00
clocksource	…
crypto	…
drm	…
dt-bindings	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2021-05-06 23:37:55 -07:00
keys	integrity-v5.13	2021-05-01 15:32:18 -07:00
kunit	…
kvm	…
linux	bpf: Support socket migration by eBPF.	2021-06-15 18:01:06 +02:00
math-emu	…
media	…
memory	…
misc	…
net	tcp: Add reuseport_migrate_sock() to select a new listener.	2021-06-15 18:01:05 +02:00
pcmcia	…
ras	…
rdma	…
scsi	…
soc	…
sound	…
target	…
trace	xdp: Extend xdp_redirect_map with broadcast support	2021-05-26 09:46:16 +02:00
uapi	bpf: Support socket migration by eBPF.	2021-06-15 18:01:06 +02:00
vdso	…
video	…
xen	Merge branch 'akpm' (patches from Andrew)	2021-05-07 00:34:51 -07:00