/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright 2013 Google Inc.
 * Author: Willem de Bruijn <willemb@google.com>
 *         Daniel Borkmann <dborkman@redhat.com>
 */

#ifndef PSOCK_LIB_H
#define PSOCK_LIB_H

#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>

#include "kselftest.h"

#define DATA_LEN                        100
#define DATA_CHAR                       'a'
#define DATA_CHAR_1                     'b'

#define PORT_BASE                       8000

static __maybe_unused void pair_udp_setfilter(int fd)
{
        /* the filter below checks for all of the following conditions that
         * are based on the contents of create_payload()
         *  ether type 0x800 and
         *  ip proto udp     and
         *  skb->len == DATA_LEN and
         *  udp[38] == 'a' or udp[38] == 'b'
         * It can be generated from the following bpf_asm input:
         *      ldh [12]
         *      jne #0x800, drop        ; ETH_P_IP
         *      ldb [23]
         *      jneq #17, drop          ; IPPROTO_UDP
         *      ld len                  ; ld skb->len
         *      jlt #100, drop          ; DATA_LEN
         *      ldb [80]
         *      jeq #97, pass           ; DATA_CHAR
         *      jne #98, drop           ; DATA_CHAR_1
         *      pass:
         *        ret #-1
         *      drop:
         *        ret #0
         */
        struct sock_filter bpf_filter[] = {
                { 0x28,  0,  0, 0x0000000c },
                { 0x15,  0,  8, 0x00000800 },
                { 0x30,  0,  0, 0x00000017 },
                { 0x15,  0,  6, 0x00000011 },
                { 0x80,  0,  0, 0000000000 },
                { 0x35,  0,  4, 0x00000064 },
                { 0x30,  0,  0, 0x00000050 },
                { 0x15,  1,  0, 0x00000061 },
                { 0x15,  0,  1, 0x00000062 },
                { 0x06,  0,  0, 0xffffffff },
                { 0x06,  0,  0, 0000000000 },
        };
        struct sock_fprog bpf_prog;

        bpf_prog.filter = bpf_filter;
        bpf_prog.len = ARRAY_SIZE(bpf_filter);

        if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf_prog,
                       sizeof(bpf_prog))) {
                perror("setsockopt SO_ATTACH_FILTER");
                exit(1);
        }
}

static __maybe_unused void pair_udp_open(int fds[], uint16_t port)
{
        struct sockaddr_in saddr, daddr;

        fds[0] = socket(PF_INET, SOCK_DGRAM, 0);
        fds[1] = socket(PF_INET, SOCK_DGRAM, 0);
        if (fds[0] == -1 || fds[1] == -1) {
                fprintf(stderr, "ERROR: socket dgram\n");
                exit(1);
        }

        memset(&saddr, 0, sizeof(saddr));
        saddr.sin_family = AF_INET;
        saddr.sin_port = htons(port);
        saddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

        memset(&daddr, 0, sizeof(daddr));
        daddr.sin_family = AF_INET;
        daddr.sin_port = htons(port + 1);
        daddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

        /* must bind both to get consistent hash result */
        if (bind(fds[1], (void *) &daddr, sizeof(daddr))) {
                perror("bind");
                exit(1);
        }
        if (bind(fds[0], (void *) &saddr, sizeof(saddr))) {
                perror("bind");
                exit(1);
        }
        if (connect(fds[0], (void *) &daddr, sizeof(daddr))) {
                perror("connect");
                exit(1);
        }
}

static __maybe_unused void pair_udp_send_char(int fds[], int num, char payload)
{
        char buf[DATA_LEN], rbuf[DATA_LEN];

        memset(buf, payload, sizeof(buf));
        while (num--) {
                /* Should really handle EINTR and EAGAIN */
                if (write(fds[0], buf, sizeof(buf)) != sizeof(buf)) {
                        fprintf(stderr, "ERROR: send failed left=%d\n", num);
                        exit(1);
                }
                if (read(fds[1], rbuf, sizeof(rbuf)) != sizeof(rbuf)) {
                        fprintf(stderr, "ERROR: recv failed left=%d\n", num);
                        exit(1);
                }
                if (memcmp(buf, rbuf, sizeof(buf))) {
                        fprintf(stderr, "ERROR: data failed left=%d\n", num);
                        exit(1);
                }
        }
}

static __maybe_unused void pair_udp_send(int fds[], int num)
{
        return pair_udp_send_char(fds, num, DATA_CHAR);
}

static __maybe_unused void pair_udp_close(int fds[])
{
        close(fds[0]);
        close(fds[1]);
}

#endif /* PSOCK_LIB_H */