57dc6f3b41
Andrey pointed out that we can use reno instead of dctcp for CC
tests and drop CONFIG_TCP_CONG_DCTCP=y requirement.
Fixes: beecf11bc218 ("bpf: Bpf_{g,s}etsockopt for struct bpf_sock_addr")
Suggested-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200501224320.28441-1-sdf@google.com
123 lines
2.6 KiB
C
123 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2018 Facebook
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#include <string.h>
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#include <linux/stddef.h>
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#include <linux/bpf.h>
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#include <linux/in.h>
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#include <linux/in6.h>
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#include <sys/socket.h>
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#include <netinet/tcp.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_endian.h>
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#define SRC_REWRITE_IP4 0x7f000004U
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#define DST_REWRITE_IP4 0x7f000001U
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#define DST_REWRITE_PORT4 4444
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#ifndef TCP_CA_NAME_MAX
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#define TCP_CA_NAME_MAX 16
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#endif
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int _version SEC("version") = 1;
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__attribute__ ((noinline))
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int do_bind(struct bpf_sock_addr *ctx)
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{
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struct sockaddr_in sa = {};
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sa.sin_family = AF_INET;
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sa.sin_port = bpf_htons(0);
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sa.sin_addr.s_addr = bpf_htonl(SRC_REWRITE_IP4);
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if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
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return 0;
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return 1;
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}
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static __inline int verify_cc(struct bpf_sock_addr *ctx,
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char expected[TCP_CA_NAME_MAX])
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{
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char buf[TCP_CA_NAME_MAX];
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int i;
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if (bpf_getsockopt(ctx, SOL_TCP, TCP_CONGESTION, &buf, sizeof(buf)))
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return 1;
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for (i = 0; i < TCP_CA_NAME_MAX; i++) {
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if (buf[i] != expected[i])
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return 1;
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if (buf[i] == 0)
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break;
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}
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return 0;
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}
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static __inline int set_cc(struct bpf_sock_addr *ctx)
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{
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char reno[TCP_CA_NAME_MAX] = "reno";
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char cubic[TCP_CA_NAME_MAX] = "cubic";
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if (bpf_setsockopt(ctx, SOL_TCP, TCP_CONGESTION, &reno, sizeof(reno)))
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return 1;
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if (verify_cc(ctx, reno))
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return 1;
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if (bpf_setsockopt(ctx, SOL_TCP, TCP_CONGESTION, &cubic, sizeof(cubic)))
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return 1;
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if (verify_cc(ctx, cubic))
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return 1;
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return 0;
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}
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SEC("cgroup/connect4")
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int connect_v4_prog(struct bpf_sock_addr *ctx)
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{
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struct bpf_sock_tuple tuple = {};
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struct bpf_sock *sk;
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/* Verify that new destination is available. */
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memset(&tuple.ipv4.saddr, 0, sizeof(tuple.ipv4.saddr));
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memset(&tuple.ipv4.sport, 0, sizeof(tuple.ipv4.sport));
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tuple.ipv4.daddr = bpf_htonl(DST_REWRITE_IP4);
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tuple.ipv4.dport = bpf_htons(DST_REWRITE_PORT4);
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if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
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return 0;
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else if (ctx->type == SOCK_STREAM)
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sk = bpf_sk_lookup_tcp(ctx, &tuple, sizeof(tuple.ipv4),
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BPF_F_CURRENT_NETNS, 0);
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else
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sk = bpf_sk_lookup_udp(ctx, &tuple, sizeof(tuple.ipv4),
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BPF_F_CURRENT_NETNS, 0);
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if (!sk)
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return 0;
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if (sk->src_ip4 != tuple.ipv4.daddr ||
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sk->src_port != DST_REWRITE_PORT4) {
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bpf_sk_release(sk);
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return 0;
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}
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bpf_sk_release(sk);
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/* Rewrite congestion control. */
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if (ctx->type == SOCK_STREAM && set_cc(ctx))
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return 0;
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/* Rewrite destination. */
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ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
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ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
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return do_bind(ctx) ? 1 : 0;
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}
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char _license[] SEC("license") = "GPL";
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