/*      $OpenBSD: print-null.c,v 1.25 2021/12/01 18:28:46 deraadt Exp $ */

/*
 * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997
 *      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: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <sys/time.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/ioctl.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/if_ether.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/tcp.h>

#include <pcap.h>
#include <stdio.h>
#include <string.h>

#include "interface.h"
#include "addrtoname.h"

#ifndef AF_NS
#define AF_NS           6               /* XEROX NS protocols */
#endif

/*
 * The DLT_NULL packet header is 4 bytes long. It contains a host
 * order 32 bit integer that specifies the family, e.g. AF_INET
 */
#define NULL_HDRLEN 4

static void
null_print(const u_char *p, const struct ip *ip, u_int length)
{
        u_int family;

        memcpy((char *)&family, (char *)p, sizeof(family));

        if (nflag && family != AF_LINK) {
                /* XXX just dump the header */
                return;
        }
        switch (family) {

        case AF_INET:
                printf("ip: ");
                break;

        case AF_INET6:
                printf("ip6: ");
                break;

        case AF_NS:
                printf("ns: ");
                break;

#ifdef __OpenBSD__
        case AF_LINK:
                ether_print(p + NULL_HDRLEN, length);
                break;
#endif
        case AF_MPLS:
                printf("mpls: ");
                break;

        default:
                printf("AF %d: ", family);
                break;
        }
}

void
loop_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
{
        *(u_int *)p = ntohl(*(u_int *)p);

        null_if_print(user, h, p);
}

void
null_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
{
        u_int length = h->len;
        u_int caplen = h->caplen;
        u_int family = *(u_int *)p;

#ifdef __OpenBSD__
        struct ether_header *ep;
        u_short ether_type;
        extern u_short extracted_ethertype;
#endif

        ts_print(&h->ts);

        if (caplen < NULL_HDRLEN) {
                printf("[|null]");
                goto out;
        }

        /*
         * Some printers want to get back at the link level addresses,
         * and/or check that they're not walking off the end of the packet.
         * Rather than pass them all the way down, we set these globals.
         */
        packetp = p;
        snapend = p + caplen;

        length -= NULL_HDRLEN;

        if (eflag)
                null_print(p, (struct ip *)(p + NULL_HDRLEN), length);

        switch (family) {
        case AF_INET:
                ip_print(p + NULL_HDRLEN, length);
                break;

        case AF_INET6:
                ip6_print(p + NULL_HDRLEN, length);
                break;

        case AF_MPLS:
                mpls_print(p + NULL_HDRLEN, length);
                break;

#ifdef __OpenBSD__
        case AF_LINK:
                if (caplen < sizeof(struct ether_header) + NULL_HDRLEN) {
                        printf("[|ether]");
                        goto out;
                }

                length -= sizeof(struct ether_header);
                caplen -= sizeof(struct ether_header);
                ep = (struct ether_header *)(p + NULL_HDRLEN);
                p += NULL_HDRLEN + sizeof(struct ether_header);
                packetp += sizeof(struct ether_header);
                ether_type = ntohs(ep->ether_type);

                extracted_ethertype = 0;
                if (ether_type <= ETHERMTU) {
                        /* Try to print the LLC-layer header & higher layers */
                        if (llc_print(p, length, caplen, ESRC(ep),
                            EDST(ep)) == 0) {
                                /* ether_type not known, print raw packet */
                                if (!eflag)
                                        ether_print((u_char *)ep, length);
                                if (extracted_ethertype) {
                                        printf("(LLC %s) ",
                                               etherproto_string(htons(extracted_ethertype)));
                                }
                                if (!xflag && !qflag)
                                        default_print(p, caplen - NULL_HDRLEN);
                        }
                } else if (ether_encap_print(ether_type, p, length,
                           caplen) == 0) {
                        /* ether_type not known, print raw packet */
                        if (!eflag)
                                ether_print((u_char *)ep, length +
                                    sizeof(*ep));
                        if (!xflag && !qflag)
                                default_print(p, caplen - NULL_HDRLEN);
                }
                break;
#endif /* __OpenBSD__ */
        }

        if (xflag)
                default_print((const u_char *)(packetp + NULL_HDRLEN),
                    caplen - NULL_HDRLEN);
 out:
        putchar('\n');
}