/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2017-2018 Covalent IO, Inc. http://covalent.io */
#include <stddef.h>
#include <string.h>
#include <linux/bpf.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/in.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <linux/pkt_cls.h>
#include <sys/socket.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
#include "bpf_misc.h"

/* Sockmap sample program connects a client and a backend together
 * using cgroups.
 *
 *    client:X <---> frontend:80 client:X <---> backend:80
 *
 * For simplicity we hard code values here and bind 1:1. The hard
 * coded values are part of the setup in sockmap.sh script that
 * is associated with this BPF program.
 *
 * The bpf_printk is verbose and prints information as connections
 * are established and verdicts are decided.
 */

struct {
        __uint(type, TEST_MAP_TYPE);
        __uint(max_entries, 20);
        __uint(key_size, sizeof(int));
        __uint(value_size, sizeof(int));
} sock_map SEC(".maps");

struct {
        __uint(type, TEST_MAP_TYPE);
        __uint(max_entries, 20);
        __uint(key_size, sizeof(int));
        __uint(value_size, sizeof(int));
} sock_map_txmsg SEC(".maps");

struct {
        __uint(type, TEST_MAP_TYPE);
        __uint(max_entries, 20);
        __uint(key_size, sizeof(int));
        __uint(value_size, sizeof(int));
} sock_map_redir SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 1);
        __type(key, int);
        __type(value, int);
} sock_apply_bytes SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 1);
        __type(key, int);
        __type(value, int);
} sock_cork_bytes SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 6);
        __type(key, int);
        __type(value, int);
} sock_bytes SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 1);
        __type(key, int);
        __type(value, int);
} sock_redir_flags SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 3);
        __type(key, int);
        __type(value, int);
} sock_skb_opts SEC(".maps");

struct {
        __uint(type, TEST_MAP_TYPE);
        __uint(max_entries, 20);
        __uint(key_size, sizeof(int));
        __uint(value_size, sizeof(int));
} tls_sock_map SEC(".maps");

SEC("sk_skb/stream_parser")
int bpf_prog1(struct __sk_buff *skb)
{
        int *f, two = 2;

        f = bpf_map_lookup_elem(&sock_skb_opts, &two);
        if (f && *f) {
                return *f;
        }
        return skb->len;
}

SEC("sk_skb/stream_verdict")
int bpf_prog2(struct __sk_buff *skb)
{
        __u32 lport = skb->local_port;
        __u32 rport = skb->remote_port;
        int len, *f, ret, zero = 0;
        __u64 flags = 0;

        __sink(rport);
        if (lport == 10000)
                ret = 10;
        else
                ret = 1;

        len = (__u32)skb->data_end - (__u32)skb->data;
        __sink(len);

        f = bpf_map_lookup_elem(&sock_skb_opts, &zero);
        if (f && *f) {
                ret = 3;
                flags = *f;
        }

#ifdef SOCKMAP
        return bpf_sk_redirect_map(skb, &sock_map, ret, flags);
#else
        return bpf_sk_redirect_hash(skb, &sock_map, &ret, flags);
#endif

}

static inline void bpf_write_pass(struct __sk_buff *skb, int offset)
{
        int err = bpf_skb_pull_data(skb, 6 + offset);
        void *data_end;
        char *c;

        if (err)
                return;

        c = (char *)(long)skb->data;
        data_end = (void *)(long)skb->data_end;

        if (c + 5 + offset < data_end)
                memcpy(c + offset, "PASS", 4);
}

SEC("sk_skb/stream_verdict")
int bpf_prog3(struct __sk_buff *skb)
{
        int err, *f, ret = SK_PASS;
        const int one = 1;

        f = bpf_map_lookup_elem(&sock_skb_opts, &one);
        if (f && *f) {
                __u64 flags = 0;

                ret = 0;
                flags = *f;

                err = bpf_skb_adjust_room(skb, -13, 0, 0);
                if (err)
                        return SK_DROP;
                err = bpf_skb_adjust_room(skb, 4, 0, 0);
                if (err)
                        return SK_DROP;
                bpf_write_pass(skb, 0);
#ifdef SOCKMAP
                return bpf_sk_redirect_map(skb, &tls_sock_map, ret, flags);
#else
                return bpf_sk_redirect_hash(skb, &tls_sock_map, &ret, flags);
#endif
        }
        err = bpf_skb_adjust_room(skb, 4, 0, 0);
        if (err)
                return SK_DROP;
        bpf_write_pass(skb, 13);
        return ret;
}

SEC("sockops")
int bpf_sockmap(struct bpf_sock_ops *skops)
{
        __u32 lport, rport;
        int op, ret;

        op = (int) skops->op;

        switch (op) {
        case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
                lport = skops->local_port;
                rport = skops->remote_port;

                if (lport == 10000) {
                        ret = 1;
#ifdef SOCKMAP
                        bpf_sock_map_update(skops, &sock_map, &ret,
                                                  BPF_NOEXIST);
#else
                        bpf_sock_hash_update(skops, &sock_map, &ret,
                                                   BPF_NOEXIST);
#endif
                }
                break;
        case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
                lport = skops->local_port;
                rport = skops->remote_port;

                if (bpf_ntohl(rport) == 10001) {
                        ret = 10;
#ifdef SOCKMAP
                        bpf_sock_map_update(skops, &sock_map, &ret,
                                                  BPF_NOEXIST);
#else
                        bpf_sock_hash_update(skops, &sock_map, &ret,
                                                   BPF_NOEXIST);
#endif
                }
                break;
        default:
                break;
        }

        return 0;
}

SEC("sk_msg")
int bpf_prog4(struct sk_msg_md *msg)
{
        int *bytes, zero = 0, one = 1, two = 2, three = 3, four = 4, five = 5;
        int *start, *end, *start_push, *end_push, *start_pop, *pop, err = 0;

        bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
        if (bytes)
                bpf_msg_apply_bytes(msg, *bytes);
        bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
        if (bytes)
                bpf_msg_cork_bytes(msg, *bytes);
        start = bpf_map_lookup_elem(&sock_bytes, &zero);
        end = bpf_map_lookup_elem(&sock_bytes, &one);
        if (start && end)
                bpf_msg_pull_data(msg, *start, *end, 0);
        start_push = bpf_map_lookup_elem(&sock_bytes, &two);
        end_push = bpf_map_lookup_elem(&sock_bytes, &three);
        if (start_push && end_push) {
                err = bpf_msg_push_data(msg, *start_push, *end_push, 0);
                if (err)
                        return SK_DROP;
        }
        start_pop = bpf_map_lookup_elem(&sock_bytes, &four);
        pop = bpf_map_lookup_elem(&sock_bytes, &five);
        if (start_pop && pop)
                bpf_msg_pop_data(msg, *start_pop, *pop, 0);
        return SK_PASS;
}

SEC("sk_msg")
int bpf_prog6(struct sk_msg_md *msg)
{
        int zero = 0, one = 1, two = 2, three = 3, four = 4, five = 5, key = 0;
        int *bytes, *start, *end, *start_push, *end_push, *start_pop, *pop, *f;
        int err = 0;
        __u64 flags = 0;

        bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
        if (bytes)
                bpf_msg_apply_bytes(msg, *bytes);
        bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
        if (bytes)
                bpf_msg_cork_bytes(msg, *bytes);

        start = bpf_map_lookup_elem(&sock_bytes, &zero);
        end = bpf_map_lookup_elem(&sock_bytes, &one);
        if (start && end)
                bpf_msg_pull_data(msg, *start, *end, 0);

        start_push = bpf_map_lookup_elem(&sock_bytes, &two);
        end_push = bpf_map_lookup_elem(&sock_bytes, &three);
        if (start_push && end_push) {
                err = bpf_msg_push_data(msg, *start_push, *end_push, 0);
                if (err)
                        return SK_DROP;
        }

        start_pop = bpf_map_lookup_elem(&sock_bytes, &four);
        pop = bpf_map_lookup_elem(&sock_bytes, &five);
        if (start_pop && pop)
                bpf_msg_pop_data(msg, *start_pop, *pop, 0);

        f = bpf_map_lookup_elem(&sock_redir_flags, &zero);
        if (f && *f) {
                key = 2;
                flags = *f;
        }
#ifdef SOCKMAP
        return bpf_msg_redirect_map(msg, &sock_map_redir, key, flags);
#else
        return bpf_msg_redirect_hash(msg, &sock_map_redir, &key, flags);
#endif
}

SEC("sk_msg")
int bpf_prog8(struct sk_msg_md *msg)
{
        void *data_end = (void *)(long) msg->data_end;
        void *data = (void *)(long) msg->data;
        int ret = 0, *bytes, zero = 0;

        bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
        if (bytes) {
                ret = bpf_msg_apply_bytes(msg, *bytes);
                if (ret)
                        return SK_DROP;
        } else {
                return SK_DROP;
        }

        __sink(data_end);
        __sink(data);

        return SK_PASS;
}

SEC("sk_msg")
int bpf_prog9(struct sk_msg_md *msg)
{
        void *data_end = (void *)(long) msg->data_end;
        void *data = (void *)(long) msg->data;
        int ret = 0, *bytes, zero = 0;

        bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
        if (bytes) {
                if (((__u64)data_end - (__u64)data) >= *bytes)
                        return SK_PASS;
                ret = bpf_msg_cork_bytes(msg, *bytes);
                if (ret)
                        return SK_DROP;
        }
        return SK_PASS;
}

SEC("sk_msg")
int bpf_prog10(struct sk_msg_md *msg)
{
        int *bytes, *start, *end, *start_push, *end_push, *start_pop, *pop;
        int zero = 0, one = 1, two = 2, three = 3, four = 4, five = 5, err = 0;

        bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
        if (bytes)
                bpf_msg_apply_bytes(msg, *bytes);
        bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
        if (bytes)
                bpf_msg_cork_bytes(msg, *bytes);
        start = bpf_map_lookup_elem(&sock_bytes, &zero);
        end = bpf_map_lookup_elem(&sock_bytes, &one);
        if (start && end)
                bpf_msg_pull_data(msg, *start, *end, 0);
        start_push = bpf_map_lookup_elem(&sock_bytes, &two);
        end_push = bpf_map_lookup_elem(&sock_bytes, &three);
        if (start_push && end_push) {
                err = bpf_msg_push_data(msg, *start_push, *end_push, 0);
                if (err)
                        return SK_PASS;
        }
        start_pop = bpf_map_lookup_elem(&sock_bytes, &four);
        pop = bpf_map_lookup_elem(&sock_bytes, &five);
        if (start_pop && pop)
                bpf_msg_pop_data(msg, *start_pop, *pop, 0);
        return SK_DROP;
}

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