// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020, Tessares SA. */
/* Copyright (c) 2022, SUSE. */

#include "bpf_tracing_net.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>

char _license[] SEC("license") = "GPL";
__u32 token = 0;

struct mptcp_storage {
        __u32 invoked;
        __u32 is_mptcp;
        struct sock *sk;
        __u32 token;
        struct sock *first;
        char ca_name[TCP_CA_NAME_MAX];
};

struct {
        __uint(type, BPF_MAP_TYPE_SK_STORAGE);
        __uint(map_flags, BPF_F_NO_PREALLOC);
        __type(key, int);
        __type(value, struct mptcp_storage);
} socket_storage_map SEC(".maps");

SEC("sockops")
int _sockops(struct bpf_sock_ops *ctx)
{
        struct mptcp_storage *storage;
        struct mptcp_sock *msk;
        int op = (int)ctx->op;
        struct tcp_sock *tsk;
        struct bpf_sock *sk;
        bool is_mptcp;

        if (op != BPF_SOCK_OPS_TCP_CONNECT_CB)
                return 1;

        sk = ctx->sk;
        if (!sk)
                return 1;

        tsk = bpf_skc_to_tcp_sock(sk);
        if (!tsk)
                return 1;

        is_mptcp = bpf_core_field_exists(tsk->is_mptcp) ? tsk->is_mptcp : 0;
        if (!is_mptcp) {
                storage = bpf_sk_storage_get(&socket_storage_map, sk, 0,
                                             BPF_SK_STORAGE_GET_F_CREATE);
                if (!storage)
                        return 1;

                storage->token = 0;
                __builtin_memset(storage->ca_name, 0, TCP_CA_NAME_MAX);
                storage->first = NULL;
        } else {
                msk = bpf_skc_to_mptcp_sock(sk);
                if (!msk)
                        return 1;

                storage = bpf_sk_storage_get(&socket_storage_map, msk, 0,
                                             BPF_SK_STORAGE_GET_F_CREATE);
                if (!storage)
                        return 1;

                storage->token = msk->token;
                __builtin_memcpy(storage->ca_name, msk->ca_name, TCP_CA_NAME_MAX);
                storage->first = msk->first;
        }
        storage->invoked++;
        storage->is_mptcp = is_mptcp;
        storage->sk = (struct sock *)sk;

        return 1;
}

SEC("fentry/mptcp_pm_new_connection")
int BPF_PROG(trace_mptcp_pm_new_connection, struct mptcp_sock *msk,
             const struct sock *ssk, int server_side)
{
        if (!server_side)
                token = msk->token;

        return 0;
}