/*      $NetBSD: pf.c,v 1.14 2026/04/08 16:51:27 htodd Exp $    */

/*
 * Copyright (c) 1993-95 Mats O Jansson.  All rights reserved.
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is partly derived from rarpd.
 *
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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 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 "port.h"
#ifndef lint
__RCSID("$NetBSD: pf.c,v 1.14 2026/04/08 16:51:27 htodd Exp $");
#endif

#include "os.h"

#include <paths.h>
#include <sys/uio.h>
#include <net/bpf.h>

#include "mopdef.h"
#include "pf.h"
#include "log.h"

/*
 * Variables
 */

extern int promisc;

/*
 * Return information to device.c how to open device.
 * In this case the driver can handle both Ethernet type II and
 * IEEE 802.3 frames (SNAP) in a single pfOpen.
 */

int
pfTrans(const char *interface)
{
        return TRANS_ETHER+TRANS_8023+TRANS_AND;
}

/*
 * Open and initialize packet filter.
 */

int
pfInit(const char *interface, int mode, u_short protocol, int typ)
{
        int     fd;
        struct ifreq ifr;
        u_int   dlt;
        int     immediate;
        u_int   bufsize;
        const char *device = _PATH_BPF;

        static struct bpf_insn insns[] = {
                BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 12),
                BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 4, 0),
                BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 20),
                BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 0, 3),
                BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 14),
                BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0xaaaa, 0, 1),
                BPF_STMT(BPF_RET | BPF_K, 1520),
                BPF_STMT(BPF_RET | BPF_K, 0),
        };
        static struct bpf_program filter = {
                sizeof insns / sizeof(insns[0]),
                insns
        };
        
        fd = open(device, mode);
        if (fd < 0) {
                mopLogWarn("pfInit: open %s", device);
                return(-1);
        }
  
        /* Set immediate mode so packets are processed as they arrive. */
        immediate = 1;
        if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) {
                mopLogWarn("pfInit: BIOCIMMEDIATE");
                return(-1);
        }
        bufsize = 32768;
        if (ioctl(fd, BIOCSBLEN, &bufsize) < 0) {
                mopLogWarn("pfInit: BIOCSBLEN(%d)", bufsize);
        }
        (void) strncpy(ifr.ifr_name, interface, sizeof ifr.ifr_name);
        if (ioctl(fd, BIOCSETIF, (caddr_t) & ifr) < 0) {
                mopLogWarn("pfInit: BIOCSETIF");
                return(-1);
        }
        /* Check that the data link layer is an Ethernet; this code won't work
         * with anything else. */
        if (ioctl(fd, BIOCGDLT, (caddr_t) & dlt) < 0) {
                mopLogWarn("pfInit: BIOCGDLT");
                return(-1);
        }
        if (dlt != DLT_EN10MB) {
                mopLogWarnX("pfInit: %s is not Ethernet", device);
                return(-1);
        }
        if (promisc) {
                /* Set promiscuous mode. */
                if (ioctl(fd, BIOCPROMISC, (caddr_t)0) < 0) {
                        mopLogWarn("pfInit: BIOCPROMISC");
                        return(-1);
                }
        }
        /* Set filter program. */
        insns[1].k = protocol;
        insns[3].k = protocol;

        if (ioctl(fd, BIOCSETF, (caddr_t) & filter) < 0) {
                mopLogWarn("pfInit: BIOCSETF");
                return(-1);
        }
        return(fd);
}

/*
 * Add a Multicast address to the interface
 */

int
pfAddMulti(int s, const char *interface, const char *addr)
{
        struct ifreq ifr;
        int     fd;
        
        strncpy(ifr.ifr_name, interface, sizeof(ifr.ifr_name));

        ifr.ifr_addr.sa_family = AF_UNSPEC;
        memmove(ifr.ifr_addr.sa_data, addr, 6);
        
        /*
         * open a socket, temporarily, to use for SIOC* ioctls
         *
         */
        if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
                mopLogWarn("pfAddMulti: socket");
                return(-1);
        }
        if (ioctl(fd, SIOCADDMULTI, (caddr_t)&ifr) < 0) {
                mopLogWarn("pfAddMulti: SIOCADDMULTI");
                close(fd);
                return(-1);
        }
        close(fd);
        
        return(0);
}

/*
 * Delete a Multicast address from the interface
 */

int
pfDelMulti(int s, const char *interface, const char *addr)
{
        struct ifreq ifr;
        int     fd;
        
        strncpy(ifr.ifr_name, interface, sizeof(ifr.ifr_name));
        
        ifr.ifr_addr.sa_family = AF_UNSPEC;
        memmove(ifr.ifr_addr.sa_data, addr, 6);
        
        /*
         * open a socket, temporarily, to use for SIOC* ioctls
         *
         */
        if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
                mopLogWarn("pfDelMulti: socket");
                return(-1);
        }
        if (ioctl(fd, SIOCDELMULTI, (caddr_t)&ifr) < 0) {
                mopLogWarn("pfAddMulti: SIOCDELMULTI");
                close(fd);
                return(-1);
        }
        close(fd);
        
        return(0);
}

/*
 * read a packet
 */

int
pfRead(int fd, u_char *buf, int len)
{
        return(read(fd, buf, len));
}

/*
 * write a packet
 */

int
pfWrite(int fd, const u_char *buf, int len, int trans)
{
        
        struct iovec iov[2];
        
        switch (trans) {
        case TRANS_8023:
                iov[0].iov_base = (caddr_t)__UNCONST(buf);
                iov[0].iov_len = 22;
                iov[1].iov_base = (caddr_t)__UNCONST(buf+22);
                iov[1].iov_len = len-22;
                break;
        default:
                iov[0].iov_base = (caddr_t)__UNCONST(buf);
                iov[0].iov_len = 14;
                iov[1].iov_base = (caddr_t)__UNCONST(buf+14);
                iov[1].iov_len = len-14;
                break;
        }

        if (writev(fd, iov, 2) == len)
                return(len);
        
        return(-1);
}