bpf_smc.c

  1// SPDX-License-Identifier: GPL-2.0
  2
  3#include "vmlinux.h"
  4
  5#include <bpf/bpf_helpers.h>
  6#include <bpf/bpf_tracing.h>
  7#include "bpf_tracing_net.h"
  8
  9char _license[] SEC("license") = "GPL";
 10
 11enum {
 12	BPF_SMC_LISTEN	= 10,
 13};
 14
 15struct smc_sock___local {
 16	struct sock sk;
 17	struct smc_sock *listen_smc;
 18	bool use_fallback;
 19} __attribute__((preserve_access_index));
 20
 21int smc_cnt = 0;
 22int fallback_cnt = 0;
 23
 24SEC("fentry/smc_release")
 25int BPF_PROG(bpf_smc_release, struct socket *sock)
 26{
 27	/* only count from one side (client) */
 28	if (sock->sk->__sk_common.skc_state == BPF_SMC_LISTEN)
 29		return 0;
 30	smc_cnt++;
 31	return 0;
 32}
 33
 34SEC("fentry/smc_switch_to_fallback")
 35int BPF_PROG(bpf_smc_switch_to_fallback, struct smc_sock___local *smc)
 36{
 37	/* only count from one side (client) */
 38	if (smc && !smc->listen_smc)
 39		fallback_cnt++;
 40	return 0;
 41}
 42
 43/* go with default value if no strat was found */
 44bool default_ip_strat_value = true;
 45
 46struct smc_policy_ip_key {
 47	__u32	sip;
 48	__u32	dip;
 49};
 50
 51struct smc_policy_ip_value {
 52	__u8	mode;
 53};
 54
 55struct {
 56	__uint(type, BPF_MAP_TYPE_HASH);
 57	__uint(key_size, sizeof(struct smc_policy_ip_key));
 58	__uint(value_size, sizeof(struct smc_policy_ip_value));
 59	__uint(max_entries, 128);
 60	__uint(map_flags, BPF_F_NO_PREALLOC);
 61} smc_policy_ip SEC(".maps");
 62
 63static bool smc_check(__u32 src, __u32 dst)
 64{
 65	struct smc_policy_ip_value *value;
 66	struct smc_policy_ip_key key = {
 67		.sip = src,
 68		.dip = dst,
 69	};
 70
 71	value = bpf_map_lookup_elem(&smc_policy_ip, &key);
 72	return value ? value->mode : default_ip_strat_value;
 73}
 74
 75SEC("fmod_ret/update_socket_protocol")
 76int BPF_PROG(smc_run, int family, int type, int protocol)
 77{
 78	struct task_struct *task;
 79
 80	if (family != AF_INET && family != AF_INET6)
 81		return protocol;
 82
 83	if ((type & 0xf) != SOCK_STREAM)
 84		return protocol;
 85
 86	if (protocol != 0 && protocol != IPPROTO_TCP)
 87		return protocol;
 88
 89	task = bpf_get_current_task_btf();
 90	/* Prevent from affecting other tests */
 91	if (!task || !task->nsproxy->net_ns->smc.hs_ctrl)
 92		return protocol;
 93
 94	return IPPROTO_SMC;
 95}
 96
 97SEC("struct_ops")
 98int BPF_PROG(bpf_smc_set_tcp_option_cond, const struct tcp_sock *tp,
 99	     struct inet_request_sock *ireq)
100{
101	return smc_check(ireq->req.__req_common.skc_daddr,
102			 ireq->req.__req_common.skc_rcv_saddr);
103}
104
105SEC("struct_ops")
106int BPF_PROG(bpf_smc_set_tcp_option, struct tcp_sock *tp)
107{
108	return smc_check(tp->inet_conn.icsk_inet.sk.__sk_common.skc_rcv_saddr,
109			 tp->inet_conn.icsk_inet.sk.__sk_common.skc_daddr);
110}
111
112SEC(".struct_ops")
113struct smc_hs_ctrl  linkcheck = {
114	.name		= "linkcheck",
115	.syn_option	= (void *)bpf_smc_set_tcp_option,
116	.synack_option	= (void *)bpf_smc_set_tcp_option_cond,
117};