/*      $OpenBSD: inet.c,v 1.28 2024/08/28 11:41:42 op Exp $    */

/*
 * Copyright (c) 1994, 1995, 1996, 1997, 1998
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the Computer Systems
 *      Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS 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/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#include <sys/time.h>                           /* concession to AIX */

#include <net/if.h>
#include <netinet/in.h>

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifdef HAVE_IFADDRS_H
#include <ifaddrs.h>
#endif

#include "pcap-int.h"

#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

/*
 * Free a list of interfaces.
 */
void
pcap_freealldevs(pcap_if_t *alldevs)
{
        pcap_if_t *curdev, *nextdev;
        pcap_addr_t *curaddr, *nextaddr;

        for (curdev = alldevs; curdev != NULL; curdev = nextdev) {
                nextdev = curdev->next;

                /*
                 * Free all addresses.
                 */
                for (curaddr = curdev->addresses; curaddr != NULL;
                    curaddr = nextaddr) {
                        nextaddr = curaddr->next;
                        free(curaddr->addr);
                        free(curaddr->netmask);
                        free(curaddr->broadaddr);
                        free(curaddr->dstaddr);
                        free(curaddr);
                }

                /*
                 * Free the name string.
                 */
                free(curdev->name);

                /*
                 * Free the description string, if any.
                 */
                free(curdev->description);

                /*
                 * Free the interface.
                 */
                free(curdev);
        }
}

/*
 * Return the name of a network interface attached to the system, or NULL
 * if none can be found.  The interface must be configured up; the
 * lowest unit number is preferred; loopback is ignored.
 */
char *
pcap_lookupdev(char *errbuf)
{
#ifdef HAVE_IFADDRS_H
        struct ifaddrs *ifap, *ifa, *mp;
        int n, minunit;
        char *cp;
        const char *errstr;
        static char device[IF_NAMESIZE + 1];

        if (getifaddrs(&ifap) != 0) {
                (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                    "getifaddrs: %s", pcap_strerror(errno));
                return NULL;
        }

        mp = NULL;
        minunit = 666;
        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                if ((ifa->ifa_flags & IFF_UP) == 0)
                        continue;
                if (ISLOOPBACK(ifa->ifa_name, ifa->ifa_flags))
                        continue;
                for (cp = ifa->ifa_name; !isdigit((unsigned char)*cp); ++cp)
                        continue;
                n = strtonum(cp, 0, INT_MAX, &errstr);
                if (errstr != NULL)
                        continue;
                if (n < minunit) {
                        minunit = n;
                        mp = ifa;
                }
        }
        if (mp == NULL) {
                (void)strlcpy(errbuf, "no suitable device found",
                    PCAP_ERRBUF_SIZE);
                freeifaddrs(ifap);
                return (NULL);
        }

        (void)strlcpy(device, mp->ifa_name, sizeof(device));
        freeifaddrs(ifap);
        return (device);
#else
        int fd, minunit, n;
        char *cp;
        const char *errstr;
        struct ifreq *ifrp, *ifend, *ifnext, *mp;
        struct ifconf ifc;
        struct ifreq ibuf[16], ifr;
        static char device[sizeof(ifrp->ifr_name) + 1];

        fd = socket(AF_INET, SOCK_DGRAM, 0);
        if (fd == -1) {
                (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
                    pcap_strerror(errno));
                return (NULL);
        }
        ifc.ifc_len = sizeof ibuf;
        ifc.ifc_buf = (caddr_t)ibuf;

        memset((char *)ibuf, 0, sizeof(ibuf));
        if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) == -1 ||
            ifc.ifc_len < sizeof(struct ifreq)) {
                (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s",
                    pcap_strerror(errno));
                (void)close(fd);
                return (NULL);
        }
        ifrp = ibuf;
        ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);

        mp = NULL;
        minunit = 666;
        for (; ifrp < ifend; ifrp = ifnext) {
#ifdef HAVE_SOCKADDR_SA_LEN
                n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
                if (n < sizeof(*ifrp))
                        ifnext = ifrp + 1;
                else
                        ifnext = (struct ifreq *)((char *)ifrp + n);
                if (ifrp->ifr_addr.sa_family != AF_INET)
                        continue;
#else
                ifnext = ifrp + 1;
#endif
                /*
                 * Need a template to preserve address info that is
                 * used below to locate the next entry.  (Otherwise,
                 * SIOCGIFFLAGS stomps over it because the requests
                 * are returned in a union.)
                 */
                (void)strlcpy(ifr.ifr_name, ifrp->ifr_name,
                    sizeof(ifr.ifr_name));
                if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) == -1) {
                        if (errno == ENXIO)
                                continue;
                        (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                            "SIOCGIFFLAGS: %.*s: %s",
                            (int)sizeof(ifr.ifr_name), ifr.ifr_name,
                            pcap_strerror(errno));
                        (void)close(fd);
                        return (NULL);
                }

                /* Must be up and not the loopback */
                if ((ifr.ifr_flags & IFF_UP) == 0 || 
                    ISLOOPBACK(ifr.ifr_name, ifr.ifr_flags))
                        continue;

                for (cp = ifrp->ifr_name; !isdigit((unsigned char)*cp); ++cp)
                        continue;
                n = strtonum(cp, 0, INT_MAX, &errstr);
                if (errstr != NULL)
                        continue;
                if (n < minunit) {
                        minunit = n;
                        mp = ifrp;
                }
        }
        (void)close(fd);
        if (mp == NULL) {
                (void)strlcpy(errbuf, "no suitable device found",
                    PCAP_ERRBUF_SIZE);
                return (NULL);
        }

        (void)strlcpy(device, mp->ifr_name, sizeof(device));
        return (device);
#endif
}

int
pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp,
    char *errbuf)
{
        int fd;
        struct sockaddr_in *sin;
        struct ifreq ifr;

        fd = socket(AF_INET, SOCK_DGRAM, 0);
        if (fd == -1) {
                (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
                    pcap_strerror(errno));
                return (-1);
        }
        memset(&ifr, 0, sizeof(ifr));
#ifdef linux
        /* XXX Work around Linux kernel bug */
        ifr.ifr_addr.sa_family = AF_INET;
#endif
        (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
        if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) == -1) {
                if (errno == EADDRNOTAVAIL) {
                        (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                            "%s: no IPv4 address assigned", device);
                } else {
                        (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                            "SIOCGIFADDR: %s: %s",
                            device, pcap_strerror(errno));
                }
                (void)close(fd);
                return (-1);
        }
        sin = (struct sockaddr_in *)&ifr.ifr_addr;
        *netp = sin->sin_addr.s_addr;
        if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) == -1) {
                (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                    "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno));
                (void)close(fd);
                return (-1);
        }
        (void)close(fd);
        *maskp = sin->sin_addr.s_addr;
        if (*maskp == 0) {
                if (IN_CLASSA(*netp))
                        *maskp = IN_CLASSA_NET;
                else if (IN_CLASSB(*netp))
                        *maskp = IN_CLASSB_NET;
                else if (IN_CLASSC(*netp))
                        *maskp = IN_CLASSC_NET;
                else {
                        (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                            "inet class for 0x%x unknown", *netp);
                        return (-1);
                }
        }
        *netp &= *maskp;
        return (0);
}