34f79502bb
SK_SKB BPF programs are run from the socket/tcp context but early in the stack before much of the TCP metadata is needed in tcp_skb_cb. So we can use some unused fields to place BPF metadata needed for SK_SKB programs when implementing the redirect function. This allows us to drop the preempt disable logic. It does however require an API change so sk_redirect_map() has been updated to additionally provide ctx_ptr to skb. Note, we do however continue to disable/enable preemption around actual BPF program running to account for map updates. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
109 lines
2.7 KiB
C
109 lines
2.7 KiB
C
/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <uapi/linux/bpf.h>
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#include <uapi/linux/if_ether.h>
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#include <uapi/linux/if_packet.h>
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#include <uapi/linux/ip.h>
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#include "../../tools/testing/selftests/bpf/bpf_helpers.h"
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#include "../../tools/testing/selftests/bpf/bpf_endian.h"
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/* Sockmap sample program connects a client and a backend together
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* using cgroups.
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*
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* client:X <---> frontend:80 client:X <---> backend:80
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*
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* For simplicity we hard code values here and bind 1:1. The hard
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* coded values are part of the setup in sockmap.sh script that
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* is associated with this BPF program.
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*
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* The bpf_printk is verbose and prints information as connections
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* are established and verdicts are decided.
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*/
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#define bpf_printk(fmt, ...) \
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({ \
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char ____fmt[] = fmt; \
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bpf_trace_printk(____fmt, sizeof(____fmt), \
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##__VA_ARGS__); \
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})
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struct bpf_map_def SEC("maps") sock_map = {
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.type = BPF_MAP_TYPE_SOCKMAP,
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.key_size = sizeof(int),
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.value_size = sizeof(int),
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.max_entries = 20,
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};
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SEC("sk_skb1")
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int bpf_prog1(struct __sk_buff *skb)
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{
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return skb->len;
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}
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SEC("sk_skb2")
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int bpf_prog2(struct __sk_buff *skb)
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{
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__u32 lport = skb->local_port;
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__u32 rport = skb->remote_port;
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int ret = 0;
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if (lport == 10000)
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ret = 10;
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else
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ret = 1;
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bpf_printk("sockmap: %d -> %d @ %d\n", lport, bpf_ntohl(rport), ret);
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return bpf_sk_redirect_map(skb, &sock_map, ret, 0);
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}
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SEC("sockops")
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int bpf_sockmap(struct bpf_sock_ops *skops)
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{
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__u32 lport, rport;
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int op, err = 0, index, key, ret;
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op = (int) skops->op;
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switch (op) {
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case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
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lport = skops->local_port;
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rport = skops->remote_port;
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if (lport == 10000) {
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ret = 1;
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err = bpf_sock_map_update(skops, &sock_map, &ret,
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BPF_NOEXIST);
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bpf_printk("passive(%i -> %i) map ctx update err: %d\n",
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lport, bpf_ntohl(rport), err);
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}
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break;
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case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
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lport = skops->local_port;
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rport = skops->remote_port;
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if (bpf_ntohl(rport) == 10001) {
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ret = 10;
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err = bpf_sock_map_update(skops, &sock_map, &ret,
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BPF_NOEXIST);
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bpf_printk("active(%i -> %i) map ctx update err: %d\n",
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lport, bpf_ntohl(rport), err);
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}
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break;
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default:
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break;
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}
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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