forked from luck/tmp_suning_uos_patched
e9ddbb7707
Add a new program type BPF_PROG_TYPE_SK_LOOKUP with a dedicated attach type
BPF_SK_LOOKUP. The new program kind is to be invoked by the transport layer
when looking up a listening socket for a new connection request for
connection oriented protocols, or when looking up an unconnected socket for
a packet for connection-less protocols.
When called, SK_LOOKUP BPF program can select a socket that will receive
the packet. This serves as a mechanism to overcome the limits of what
bind() API allows to express. Two use-cases driving this work are:
(1) steer packets destined to an IP range, on fixed port to a socket
192.0.2.0/24, port 80 -> NGINX socket
(2) steer packets destined to an IP address, on any port to a socket
198.51.100.1, any port -> L7 proxy socket
In its run-time context program receives information about the packet that
triggered the socket lookup. Namely IP version, L4 protocol identifier, and
address 4-tuple. Context can be further extended to include ingress
interface identifier.
To select a socket BPF program fetches it from a map holding socket
references, like SOCKMAP or SOCKHASH, and calls bpf_sk_assign(ctx, sk, ...)
helper to record the selection. Transport layer then uses the selected
socket as a result of socket lookup.
In its basic form, SK_LOOKUP acts as a filter and hence must return either
SK_PASS or SK_DROP. If the program returns with SK_PASS, transport should
look for a socket to receive the packet, or use the one selected by the
program if available, while SK_DROP informs the transport layer that the
lookup should fail.
This patch only enables the user to attach an SK_LOOKUP program to a
network namespace. Subsequent patches hook it up to run on local delivery
path in ipv4 and ipv6 stacks.
Suggested-by: Marek Majkowski <marek@cloudflare.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200717103536.397595-3-jakub@cloudflare.com
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| .. | ||
| arraymap.c | ||
| bpf_iter.c | ||
| bpf_lru_list.c | ||
| bpf_lru_list.h | ||
| bpf_lsm.c | ||
| bpf_struct_ops_types.h | ||
| bpf_struct_ops.c | ||
| btf.c | ||
| cgroup.c | ||
| core.c | ||
| cpumap.c | ||
| devmap.c | ||
| disasm.c | ||
| disasm.h | ||
| dispatcher.c | ||
| hashtab.c | ||
| helpers.c | ||
| inode.c | ||
| local_storage.c | ||
| lpm_trie.c | ||
| Makefile | ||
| map_in_map.c | ||
| map_in_map.h | ||
| map_iter.c | ||
| net_namespace.c | ||
| offload.c | ||
| percpu_freelist.c | ||
| percpu_freelist.h | ||
| queue_stack_maps.c | ||
| reuseport_array.c | ||
| ringbuf.c | ||
| stackmap.c | ||
| syscall.c | ||
| sysfs_btf.c | ||
| task_iter.c | ||
| tnum.c | ||
| trampoline.c | ||
| verifier.c | ||