/*      $NetBSD: t_bpfilter.c,v 1.11 2017/01/13 21:30:42 christos Exp $ */

/*-
 * Copyright (c) 2012 The NetBSD Foundation, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include <sys/cdefs.h>
__RCSID("$NetBSD: t_bpfilter.c,v 1.11 2017/01/13 21:30:42 christos Exp $");

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/mbuf.h>
#include <sys/sysctl.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <unistd.h>

#include <net/if.h>
#include <net/if_ether.h>
#include <net/bpf.h>

#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#include <rump/rump.h>
#include <rump/rump_syscalls.h>

/* XXX: atf-c.h has collisions with mbuf */
#undef m_type
#undef m_data
#include <atf-c.h>

#include "h_macros.h"
#include "../config/netconfig.c"


#define SNAPLEN UINT32_MAX

#define BMAGIC UINT32_C(0x37)
#define HMAGIC UINT32_C(0xc2c2)
#define WMAGIC UINT32_C(0x7d7d7d7d)

static const char magic_echo_reply_tail[7] = {
        BMAGIC,
        HMAGIC & 0xff,
        HMAGIC & 0xff,
        WMAGIC & 0xff,
        WMAGIC & 0xff,
        WMAGIC & 0xff,
        WMAGIC & 0xff
};

/*
 * Match ICMP_ECHOREPLY packet with 7 magic bytes at the end.
 */
static struct bpf_insn magic_echo_reply_prog[] = {
        BPF_STMT(BPF_LD+BPF_ABS+BPF_B,
            sizeof(struct ip) + offsetof(struct icmp, icmp_type)),
        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, ICMP_ECHOREPLY, 1, 0),
        BPF_STMT(BPF_RET+BPF_K, 0),

        BPF_STMT(BPF_LD+BPF_W+BPF_LEN, 0),  /* A <- len   */
        BPF_STMT(BPF_ALU+BPF_SUB+BPF_K, 7), /* A <- A - 7 */
        BPF_STMT(BPF_MISC+BPF_TAX, 0),      /* X <- A     */

        BPF_STMT(BPF_LD+BPF_IND+BPF_B, 0),
        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, BMAGIC, 1, 0),
        BPF_STMT(BPF_RET+BPF_K, 0),

        BPF_STMT(BPF_LD+BPF_IND+BPF_H, 1),
        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, HMAGIC, 1, 0),
        BPF_STMT(BPF_RET+BPF_K, 0),

        BPF_STMT(BPF_LD+BPF_IND+BPF_W, 3),
        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, WMAGIC, 1, 0),
        BPF_STMT(BPF_RET+BPF_K, 0),

        BPF_STMT(BPF_RET+BPF_K, SNAPLEN)
};

static struct bpf_insn badmem_prog[] = {
        BPF_STMT(BPF_LD+BPF_MEM, 5),
        BPF_STMT(BPF_RET+BPF_A, 0),
};

static struct bpf_insn noinitA_prog[] = {
        BPF_STMT(BPF_RET+BPF_A, 0),
};

static struct bpf_insn noinitX_prog[] = {
        BPF_STMT(BPF_MISC+BPF_TXA, 0),
        BPF_STMT(BPF_RET+BPF_A, 0),
};

static struct bpf_insn badjmp_prog[] = {
        BPF_STMT(BPF_JMP+BPF_JA, 5),
        BPF_STMT(BPF_RET+BPF_A, 0),
};

static struct bpf_insn negjmp_prog[] = {
        BPF_STMT(BPF_JMP+BPF_JA, 0),
        BPF_STMT(BPF_JMP+BPF_JA, UINT32_MAX - 1), // -2
        BPF_STMT(BPF_RET+BPF_A, 0),
};

static struct bpf_insn badret_prog[] = {
        BPF_STMT(BPF_RET+BPF_A+0x8000, 0),
};

static uint16_t
in_cksum(void *data, size_t len)
{
        uint16_t *buf = data;
        unsigned sum;

        for (sum = 0; len > 1; len -= 2)
                sum += *buf++;
        if (len)
                sum += *(uint8_t *)buf;

        sum = (sum >> 16) + (sum & 0xffff);
        sum += (sum >> 16);

        return ~sum;
}

/*
 * Based on netcfg_rump_pingtest().
 */
static bool __unused
pingtest(const char *dst, unsigned int wirelen, const char tail[7])
{
        struct timeval tv;
        struct sockaddr_in sin;
        struct icmp *icmp;
        char *pkt;
        unsigned int pktsize;
        socklen_t slen;
        int s;
        bool rv = false;

        if (wirelen < ETHER_HDR_LEN + sizeof(struct ip))
                return false;

        pktsize = wirelen - ETHER_HDR_LEN - sizeof(struct ip);
        if (pktsize < sizeof(struct icmp) + 7)
                return false;

        s = rump_sys_socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
        if (s == -1)
                return false;

        pkt = NULL;

        tv.tv_sec = 1;
        tv.tv_usec = 0;
        if (rump_sys_setsockopt(s, SOL_SOCKET, SO_RCVTIMEO,
            &tv, sizeof(tv)) == -1)
                goto out;

        memset(&sin, 0, sizeof(sin));
        sin.sin_len = sizeof(sin);
        sin.sin_family = AF_INET;
        sin.sin_addr.s_addr = inet_addr(dst);

        pkt = calloc(1, pktsize);
        icmp = (struct icmp *)pkt;
        if (pkt == NULL)
                goto out;

        memcpy(pkt + pktsize - 7, tail, 7);
        icmp->icmp_type = ICMP_ECHO;
        icmp->icmp_id = htons(37);
        icmp->icmp_seq = htons(1);
        icmp->icmp_cksum = in_cksum(pkt, pktsize);

        slen = sizeof(sin);
        if (rump_sys_sendto(s, pkt, pktsize, 0,
            (struct sockaddr *)&sin, slen) == -1) {
                goto out;
        }

        if (rump_sys_recvfrom(s, pkt, pktsize, 0,
            (struct sockaddr *)&sin, &slen) == -1)
                goto out;

        rv = true;
 out:
        if (pkt != NULL)
                free(pkt);
        rump_sys_close(s);
        return rv;
}

static void
magic_ping_test(const char *name, unsigned int wirelen)
{
        struct bpf_program prog;
        struct bpf_stat bstat;
        struct ifreq ifr;
        struct timeval tv;
        unsigned int bufsize;
        bool pinged;
        ssize_t n;
        char *buf;
        pid_t child;
        int bpfd;
        char token;
        int channel[2];

        struct bpf_hdr *hdr;

        RL(pipe(channel));

        prog.bf_len = __arraycount(magic_echo_reply_prog);
        prog.bf_insns = magic_echo_reply_prog;

        child = fork();
        RZ(rump_init());
        netcfg_rump_makeshmif(name, ifr.ifr_name);

        switch (child) {
        case -1:
                atf_tc_fail_errno("fork failed");
        case 0:
                netcfg_rump_if(ifr.ifr_name, "10.1.1.10", "255.0.0.0");
                close(channel[0]);
                ATF_CHECK(write(channel[1], "U", 1) == 1);
                close(channel[1]);
                pause();
                return;
        default:
                break;
        }

        netcfg_rump_if(ifr.ifr_name, "10.1.1.20", "255.0.0.0");

        RL(bpfd = rump_sys_open("/dev/bpf", O_RDONLY));

        tv.tv_sec = 0;
        tv.tv_usec = 500;
        RL(rump_sys_ioctl(bpfd, BIOCSRTIMEOUT, &tv));

        RL(rump_sys_ioctl(bpfd, BIOCGBLEN, &bufsize));
        RL(rump_sys_ioctl(bpfd, BIOCSETF, &prog));
        RL(rump_sys_ioctl(bpfd, BIOCSETIF, &ifr));

        close(channel[1]);
        ATF_CHECK(read(channel[0], &token, 1) == 1 && token == 'U');

        pinged = pingtest("10.1.1.10", wirelen, magic_echo_reply_tail);
        ATF_CHECK(pinged);

        buf = malloc(bufsize);
        hdr = (struct bpf_hdr *)buf;
        ATF_REQUIRE(buf != NULL);
        ATF_REQUIRE(bufsize > sizeof(struct bpf_hdr));

        n = rump_sys_read(bpfd, buf, bufsize);

        ATF_CHECK(n > (int)sizeof(struct bpf_hdr));
        ATF_CHECK(hdr->bh_caplen == MIN(SNAPLEN, wirelen));

        RL(rump_sys_ioctl(bpfd, BIOCGSTATS, &bstat));
        ATF_CHECK(bstat.bs_capt >= 1); /* XXX == 1 */

        rump_sys_close(bpfd);
        free(buf);

        close(channel[0]);

        kill(child, SIGKILL);
}

static int
send_bpf_prog(const char *ifname, struct bpf_program *prog)
{
        struct ifreq ifr;
        int bpfd, e, rv;

        RZ(rump_init());
        netcfg_rump_makeshmif(ifname, ifr.ifr_name);
        netcfg_rump_if(ifr.ifr_name, "10.1.1.20", "255.0.0.0");

        RL(bpfd = rump_sys_open("/dev/bpf", O_RDONLY));

        rv = rump_sys_ioctl(bpfd, BIOCSETF, prog);
        e = errno;

        rump_sys_close(bpfd);
        errno = e;

        return rv;
}

ATF_TC(bpfiltercontig);
ATF_TC_HEAD(bpfiltercontig, tc)
{

        atf_tc_set_md_var(tc, "descr", "Checks that bpf program "
            "can read bytes from contiguous buffer.");
        atf_tc_set_md_var(tc, "timeout", "30");
}

ATF_TC_BODY(bpfiltercontig, tc)
{

        magic_ping_test("bpfiltercontig", 128);
}


ATF_TC(bpfiltermchain);
ATF_TC_HEAD(bpfiltermchain, tc)
{

        atf_tc_set_md_var(tc, "descr", "Checks that bpf program "
            "can read bytes from mbuf chain.");
        atf_tc_set_md_var(tc, "timeout", "30");
}

ATF_TC_BODY(bpfiltermchain, tc)
{

        magic_ping_test("bpfiltermchain", MINCLSIZE + 1);
}


ATF_TC(bpfilterbadmem);
ATF_TC_HEAD(bpfilterbadmem, tc)
{

        atf_tc_set_md_var(tc, "descr", "Checks that bpf program that "
            "doesn't initialize memomy store is rejected by the kernel");
        atf_tc_set_md_var(tc, "timeout", "30");
}

ATF_TC_BODY(bpfilterbadmem, tc)
{
        struct bpf_program prog;

        prog.bf_len = __arraycount(badmem_prog);
        prog.bf_insns = badmem_prog;
        ATF_CHECK_ERRNO(EINVAL, send_bpf_prog("bpfilterbadmem", &prog) == -1);
}

ATF_TC(bpfilternoinitA);
ATF_TC_HEAD(bpfilternoinitA, tc)
{

        atf_tc_set_md_var(tc, "descr", "Checks that bpf program that "
            "doesn't initialize the A register is accepted by the kernel");
        atf_tc_set_md_var(tc, "timeout", "30");
}

ATF_TC_BODY(bpfilternoinitA, tc)
{
        struct bpf_program prog;

        prog.bf_len = __arraycount(noinitA_prog);
        prog.bf_insns = noinitA_prog;
        RL(send_bpf_prog("bpfilternoinitA", &prog));
}

ATF_TC(bpfilternoinitX);
ATF_TC_HEAD(bpfilternoinitX, tc)
{

        atf_tc_set_md_var(tc, "descr", "Checks that bpf program that "
            "doesn't initialize the X register is accepted by the kernel");
        atf_tc_set_md_var(tc, "timeout", "30");
}

ATF_TC_BODY(bpfilternoinitX, tc)
{
        struct bpf_program prog;

        prog.bf_len = __arraycount(noinitX_prog);
        prog.bf_insns = noinitX_prog;
        RL(send_bpf_prog("bpfilternoinitX", &prog));
}

ATF_TC(bpfilterbadjmp);
ATF_TC_HEAD(bpfilterbadjmp, tc)
{

        atf_tc_set_md_var(tc, "descr", "Checks that bpf program that "
            "jumps to invalid destination is rejected by the kernel");
        atf_tc_set_md_var(tc, "timeout", "30");
}

ATF_TC_BODY(bpfilterbadjmp, tc)
{
        struct bpf_program prog;

        prog.bf_len = __arraycount(badjmp_prog);
        prog.bf_insns = badjmp_prog;
        ATF_CHECK_ERRNO(EINVAL, send_bpf_prog("bpfilterbadjmp", &prog) == -1);
}

ATF_TC(bpfilternegjmp);
ATF_TC_HEAD(bpfilternegjmp, tc)
{

        atf_tc_set_md_var(tc, "descr", "Checks that bpf program that "
            "jumps backwards is rejected by the kernel");
        atf_tc_set_md_var(tc, "timeout", "30");
}

ATF_TC_BODY(bpfilternegjmp, tc)
{
        struct bpf_program prog;

        prog.bf_len = __arraycount(negjmp_prog);
        prog.bf_insns = negjmp_prog;
        ATF_CHECK_ERRNO(EINVAL, send_bpf_prog("bpfilternegjmp", &prog) == -1);
}

ATF_TC(bpfilterbadret);
ATF_TC_HEAD(bpfilterbadret, tc)
{

        atf_tc_set_md_var(tc, "descr", "Checks that bpf program that "
            "ends with invalid BPF_RET instruction is rejected by the kernel");
        atf_tc_set_md_var(tc, "timeout", "30");
}

ATF_TC_BODY(bpfilterbadret, tc)
{
        struct bpf_program prog;
        struct bpf_insn *last;

        prog.bf_len = __arraycount(badret_prog);
        prog.bf_insns = badret_prog;

        /*
         * The point of this test is checking a bad instruction of
         * a valid class and with a valid BPF_RVAL data.
         */
        last = &prog.bf_insns[prog.bf_len - 1];
        ATF_CHECK(BPF_CLASS(last->code) == BPF_RET &&
            (BPF_RVAL(last->code) == BPF_K || BPF_RVAL(last->code) == BPF_A));

        ATF_CHECK_ERRNO(EINVAL, send_bpf_prog("bpfilterbadret", &prog) == -1);
}

ATF_TP_ADD_TCS(tp)
{

        ATF_TP_ADD_TC(tp, bpfiltercontig);
        ATF_TP_ADD_TC(tp, bpfiltermchain);
        ATF_TP_ADD_TC(tp, bpfilterbadmem);
        ATF_TP_ADD_TC(tp, bpfilternoinitA);
        ATF_TP_ADD_TC(tp, bpfilternoinitX);
        ATF_TP_ADD_TC(tp, bpfilterbadjmp);
        ATF_TP_ADD_TC(tp, bpfilternegjmp);
        ATF_TP_ADD_TC(tp, bpfilterbadret);

        return atf_no_error();
}