1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020, Tessares SA. */
/* Copyright (c) 2024, Kylin Software */
/* vmlinux.h, bpf_helpers.h and other 'define' */
#include "bpf_tracing_net.h"
#include "mptcp_bpf.h"
char _license[] SEC("license") = "GPL";
char cc[TCP_CA_NAME_MAX] = "reno";
int pid;
/* Associate a subflow counter to each token */
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(key_size, sizeof(__u32));
__uint(value_size, sizeof(__u32));
__uint(max_entries, 100);
} mptcp_sf SEC(".maps");
SEC("sockops")
int mptcp_subflow(struct bpf_sock_ops *skops)
{
__u32 init = 1, key, mark, *cnt;
struct mptcp_sock *msk;
struct bpf_sock *sk;
int err;
if (skops->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
return 1;
sk = skops->sk;
if (!sk)
return 1;
msk = bpf_skc_to_mptcp_sock(sk);
if (!msk)
return 1;
key = msk->token;
cnt = bpf_map_lookup_elem(&mptcp_sf, &key);
if (cnt) {
/* A new subflow is added to an existing MPTCP connection */
__sync_fetch_and_add(cnt, 1);
mark = *cnt;
} else {
/* A new MPTCP connection is just initiated and this is its primary subflow */
bpf_map_update_elem(&mptcp_sf, &key, &init, BPF_ANY);
mark = init;
}
/* Set the mark of the subflow's socket based on appearance order */
err = bpf_setsockopt(skops, SOL_SOCKET, SO_MARK, &mark, sizeof(mark));
if (err < 0)
return 1;
if (mark == 2)
err = bpf_setsockopt(skops, SOL_TCP, TCP_CONGESTION, cc, TCP_CA_NAME_MAX);
return 1;
}
static int _check_getsockopt_subflow_mark(struct mptcp_sock *msk, struct bpf_sockopt *ctx)
{
struct mptcp_subflow_context *subflow;
int i = 0;
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk;
ssk = mptcp_subflow_tcp_sock(bpf_core_cast(subflow,
struct mptcp_subflow_context));
if (ssk->sk_mark != ++i) {
ctx->retval = -2;
break;
}
}
return 1;
}
static int _check_getsockopt_subflow_cc(struct mptcp_sock *msk, struct bpf_sockopt *ctx)
{
struct mptcp_subflow_context *subflow;
mptcp_for_each_subflow(msk, subflow) {
struct inet_connection_sock *icsk;
struct sock *ssk;
ssk = mptcp_subflow_tcp_sock(bpf_core_cast(subflow,
struct mptcp_subflow_context));
icsk = bpf_core_cast(ssk, struct inet_connection_sock);
if (ssk->sk_mark == 2 &&
__builtin_memcmp(icsk->icsk_ca_ops->name, cc, TCP_CA_NAME_MAX)) {
ctx->retval = -2;
break;
}
}
return 1;
}
SEC("cgroup/getsockopt")
int _getsockopt_subflow(struct bpf_sockopt *ctx)
{
struct bpf_sock *sk = ctx->sk;
struct mptcp_sock *msk;
if (bpf_get_current_pid_tgid() >> 32 != pid)
return 1;
if (!sk || sk->protocol != IPPROTO_MPTCP ||
(!(ctx->level == SOL_SOCKET && ctx->optname == SO_MARK) &&
!(ctx->level == SOL_TCP && ctx->optname == TCP_CONGESTION)))
return 1;
msk = bpf_core_cast(sk, struct mptcp_sock);
if (msk->pm.subflows != 1) {
ctx->retval = -1;
return 1;
}
if (ctx->optname == SO_MARK)
return _check_getsockopt_subflow_mark(msk, ctx);
return _check_getsockopt_subflow_cc(msk, ctx);
}
|
