RIP: Modernize packet parsing style.

[tcpdump] / addrtoname.c

/*
 * Copyright (c) 1990, 1991, 1992, 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.
 *
 *  Internet, ethernet, port, and protocol string to address
 *  and address to string conversion routines
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_CASPER
#include <libcasper.h>
#include <casper/cap_dns.h>
#endif /* HAVE_CASPER */

#include "netdissect-stdinc.h"

#ifdef _WIN32
  /*
   * We have our own ether_ntohost(), reading from the system's
   * Ethernet address file.
   */
  #include "missing/win_ether_ntohost.h"
#else
  #ifdef USE_ETHER_NTOHOST
    #if defined(NET_ETHERNET_H_DECLARES_ETHER_NTOHOST)
      /*
       * OK, just include <net/ethernet.h>.
       */
      #include <net/ethernet.h>
    #elif defined(NETINET_ETHER_H_DECLARES_ETHER_NTOHOST)
      /*
       * OK, just include <netinet/ether.h>
       */
      #include <netinet/ether.h>
    #elif defined(SYS_ETHERNET_H_DECLARES_ETHER_NTOHOST)
      /*
       * OK, just include <sys/ethernet.h>
       */
      #include <sys/ethernet.h>
    #elif defined(ARPA_INET_H_DECLARES_ETHER_NTOHOST)
      /*
       * OK, just include <arpa/inet.h>
       */
      #include <arpa/inet.h>
    #elif defined(NETINET_IF_ETHER_H_DECLARES_ETHER_NTOHOST)
      /*
       * OK, include <netinet/if_ether.h>, after all the other stuff we
       * need to include or define for its benefit.
       */
      #define NEED_NETINET_IF_ETHER_H
    #else
      /*
       * We'll have to declare it ourselves.
       * If <netinet/if_ether.h> defines struct ether_addr, include
       * it.  Otherwise, define it ourselves.
       */
      #ifdef HAVE_STRUCT_ETHER_ADDR
        #define NEED_NETINET_IF_ETHER_H
      #else /* HAVE_STRUCT_ETHER_ADDR */
        struct ether_addr {
                unsigned char ether_addr_octet[MAC_ADDR_LEN];
        };
      #endif /* HAVE_STRUCT_ETHER_ADDR */
    #endif /* what declares ether_ntohost() */

    #ifdef NEED_NETINET_IF_ETHER_H
      #include <net/if.h>       /* Needed on some platforms */
      #include <netinet/in.h>   /* Needed on some platforms */
      #include <netinet/if_ether.h>
    #endif /* NEED_NETINET_IF_ETHER_H */

    #ifndef HAVE_DECL_ETHER_NTOHOST
      /*
       * No header declares it, so declare it ourselves.
       */
      extern int ether_ntohost(char *, const struct ether_addr *);
    #endif /* !defined(HAVE_DECL_ETHER_NTOHOST) */
  #endif /* USE_ETHER_NTOHOST */
#endif /* _WIN32 */

#include <pcap.h>
#include <pcap-namedb.h>
#ifndef HAVE_GETSERVENT
#include <getservent.h>
#endif
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "netdissect.h"
#include "addrtoname.h"
#include "addrtostr.h"
#include "ethertype.h"
#include "llc.h"
#include "extract.h"
#include "oui.h"

/*
 * hash tables for whatever-to-name translations
 *
 * ndo_error() called on strdup(3) failure with S_ERR_ND_MEM_ALLOC status
 */

#define HASHNAMESIZE 4096

struct hnamemem {
        uint32_t addr;
        const char *name;
        struct hnamemem *nxt;
};

static struct hnamemem hnametable[HASHNAMESIZE];
static struct hnamemem tporttable[HASHNAMESIZE];
static struct hnamemem uporttable[HASHNAMESIZE];
static struct hnamemem eprototable[HASHNAMESIZE];
static struct hnamemem dnaddrtable[HASHNAMESIZE];
static struct hnamemem ipxsaptable[HASHNAMESIZE];

#ifdef _WIN32
/*
 * fake gethostbyaddr for Win2k/XP
 * gethostbyaddr() returns incorrect value when AF_INET6 is passed
 * to 3rd argument.
 *
 * h_name in struct hostent is only valid.
 */
static struct hostent *
win32_gethostbyaddr(const char *addr, int len, int type)
{
        static struct hostent host;
        static char hostbuf[NI_MAXHOST];
        char hname[NI_MAXHOST];
        struct sockaddr_in6 addr6;

        host.h_name = hostbuf;
        switch (type) {
        case AF_INET:
                return gethostbyaddr(addr, len, type);
                break;
        case AF_INET6:
                memset(&addr6, 0, sizeof(addr6));
                addr6.sin6_family = AF_INET6;
                memcpy(&addr6.sin6_addr, addr, len);
                if (getnameinfo((struct sockaddr *)&addr6, sizeof(addr6),
                    hname, sizeof(hname), NULL, 0, 0)) {
                        return NULL;
                } else {
                        strlcpy(host.h_name, hname, NI_MAXHOST);
                        return &host;
                }
                break;
        default:
                return NULL;
        }
}
#define gethostbyaddr win32_gethostbyaddr
#endif /* _WIN32 */

struct h6namemem {
        nd_ipv6 addr;
        char *name;
        struct h6namemem *nxt;
};

static struct h6namemem h6nametable[HASHNAMESIZE];

struct enamemem {
        u_short e_addr0;
        u_short e_addr1;
        u_short e_addr2;
        const char *e_name;
        u_char *e_nsap;                 /* used only for nsaptable[] */
        struct enamemem *e_nxt;
};

static struct enamemem enametable[HASHNAMESIZE];
static struct enamemem nsaptable[HASHNAMESIZE];

struct bsnamemem {
        u_short bs_addr0;
        u_short bs_addr1;
        u_short bs_addr2;
        const char *bs_name;
        u_char *bs_bytes;
        unsigned int bs_nbytes;
        struct bsnamemem *bs_nxt;
};

static struct bsnamemem bytestringtable[HASHNAMESIZE];

struct protoidmem {
        uint32_t p_oui;
        u_short p_proto;
        const char *p_name;
        struct protoidmem *p_nxt;
};

static struct protoidmem protoidtable[HASHNAMESIZE];

/*
 * A faster replacement for inet_ntoa().
 */
const char *
intoa(uint32_t addr)
{
        char *cp;
        u_int byte;
        int n;
        static char buf[sizeof(".xxx.xxx.xxx.xxx")];

        addr = ntohl(addr);
        cp = buf + sizeof(buf);
        *--cp = '\0';

        n = 4;
        do {
                byte = addr & 0xff;
                *--cp = (char)(byte % 10) + '0';
                byte /= 10;
                if (byte > 0) {
                        *--cp = (char)(byte % 10) + '0';
                        byte /= 10;
                        if (byte > 0)
                                *--cp = (char)byte + '0';
                }
                *--cp = '.';
                addr >>= 8;
        } while (--n > 0);

        return cp + 1;
}

static uint32_t f_netmask;
static uint32_t f_localnet;
#ifdef HAVE_CASPER
extern cap_channel_t *capdns;
#endif

/*
 * Return a name for the IP address pointed to by ap.  This address
 * is assumed to be in network byte order.
 *
 * NOTE: ap is *NOT* necessarily part of the packet data, so you
 * *CANNOT* use the ND_TCHECK_* or ND_TTEST_* macros on it.  Furthermore,
 * even in cases where it *is* part of the packet data, the caller
 * would still have to check for a null return value, even if it's
 * just printing the return value with "%s" - not all versions of
 * printf print "(null)" with "%s" and a null pointer, some of them
 * don't check for a null pointer and crash in that case.
 *
 * The callers of this routine should, before handing this routine
 * a pointer to packet data, be sure that the data is present in
 * the packet buffer.  They should probably do those checks anyway,
 * as other data at that layer might not be IP addresses, and it
 * also needs to check whether they're present in the packet buffer.
 */
const char *
ipaddr_string(netdissect_options *ndo, const u_char *ap)
{
        struct hostent *hp;
        uint32_t addr;
        struct hnamemem *p;

        memcpy(&addr, ap, sizeof(addr));
        p = &hnametable[addr & (HASHNAMESIZE-1)];
        for (; p->nxt; p = p->nxt) {
                if (p->addr == addr)
                        return (p->name);
        }
        p->addr = addr;
        p->nxt = newhnamemem(ndo);

        /*
         * Print names unless:
         *      (1) -n was given.
         *      (2) Address is foreign and -f was given. (If -f was not
         *          given, f_netmask and f_localnet are 0 and the test
         *          evaluates to true)
         */
        if (!ndo->ndo_nflag &&
            (addr & f_netmask) == f_localnet) {
#ifdef HAVE_CASPER
                if (capdns != NULL) {
                        hp = cap_gethostbyaddr(capdns, (char *)&addr, 4,
                            AF_INET);
                } else
#endif
                        hp = gethostbyaddr((char *)&addr, 4, AF_INET);
                if (hp) {
                        char *dotp;

                        p->name = strdup(hp->h_name);
                        if (p->name == NULL)
                                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                        "%s: strdup(hp->h_name)", __func__);
                        if (ndo->ndo_Nflag) {
                                /* Remove domain qualifications */
                                dotp = strchr(p->name, '.');
                                if (dotp)
                                        *dotp = '\0';
                        }
                        return (p->name);
                }
        }
        p->name = strdup(intoa(addr));
        if (p->name == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: strdup(intoa(addr))", __func__);
        return (p->name);
}

/*
 * Return a name for the IP6 address pointed to by ap.  This address
 * is assumed to be in network byte order.
 */
const char *
ip6addr_string(netdissect_options *ndo, const u_char *ap)
{
        struct hostent *hp;
        union {
                nd_ipv6 addr;
                struct for_hash_addr {
                        char fill[14];
                        uint16_t d;
                } addra;
        } addr;
        struct h6namemem *p;
        const char *cp;
        char ntop_buf[INET6_ADDRSTRLEN];

        memcpy(&addr, ap, sizeof(addr));
        p = &h6nametable[addr.addra.d & (HASHNAMESIZE-1)];
        for (; p->nxt; p = p->nxt) {
                if (memcmp(&p->addr, &addr, sizeof(addr)) == 0)
                        return (p->name);
        }
        memcpy(p->addr, addr.addr, sizeof(nd_ipv6));
        p->nxt = newh6namemem(ndo);

        /*
         * Do not print names if -n was given.
         */
        if (!ndo->ndo_nflag) {
#ifdef HAVE_CASPER
                if (capdns != NULL) {
                        hp = cap_gethostbyaddr(capdns, (char *)&addr,
                            sizeof(addr), AF_INET6);
                } else
#endif
                        hp = gethostbyaddr((char *)&addr, sizeof(addr),
                            AF_INET6);
                if (hp) {
                        char *dotp;

                        p->name = strdup(hp->h_name);
                        if (p->name == NULL)
                                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                        "%s: strdup(hp->h_name)", __func__);
                        if (ndo->ndo_Nflag) {
                                /* Remove domain qualifications */
                                dotp = strchr(p->name, '.');
                                if (dotp)
                                        *dotp = '\0';
                        }
                        return (p->name);
                }
        }
        cp = addrtostr6(ap, ntop_buf, sizeof(ntop_buf));
        p->name = strdup(cp);
        if (p->name == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: strdup(cp)", __func__);
        return (p->name);
}

static const char hex[16] = {
        '0', '1', '2', '3', '4', '5', '6', '7',
        '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
};

/*
 * Convert an octet to two hex digits.
 *
 * Coverity appears either:
 *
 *    not to believe the C standard when it asserts that a uint8_t is
 *    exactly 8 bits in size;
 *
 *    not to believe that an unsigned type of exactly 8 bits has a value
 *    in the range of 0 to 255;
 *
 *    not to believe that, for a range of unsigned values, if you shift
 *    one of those values right by 4 bits, the maximum result value is
 *    the maximum value shifted right by 4 bits, with no stray 1's shifted
 *    in;
 *
 *    not to believe that 255 >> 4 is 15;
 *
 * so it gets upset that we're taking a "tainted" unsigned value, shifting
 * it right 4 bits, and using it as an index into a 16-element array.
 *
 * So we do a stupid pointless masking of the result of the shift with
 * 0xf, to hammer the point home to Coverity.
 */
static inline char *
octet_to_hex(char *cp, uint8_t octet)
{
        *cp++ = hex[(octet >> 4) & 0xf];
        *cp++ = hex[(octet >> 0) & 0xf];
        return (cp);
}

/* Find the hash node that corresponds the ether address 'ep' */

static struct enamemem *
lookup_emem(netdissect_options *ndo, const u_char *ep)
{
        u_int i, j, k;
        struct enamemem *tp;

        k = (ep[0] << 8) | ep[1];
        j = (ep[2] << 8) | ep[3];
        i = (ep[4] << 8) | ep[5];

        tp = &enametable[(i ^ j) & (HASHNAMESIZE-1)];
        while (tp->e_nxt)
                if (tp->e_addr0 == i &&
                    tp->e_addr1 == j &&
                    tp->e_addr2 == k)
                        return tp;
                else
                        tp = tp->e_nxt;
        tp->e_addr0 = (u_short)i;
        tp->e_addr1 = (u_short)j;
        tp->e_addr2 = (u_short)k;
        tp->e_nxt = (struct enamemem *)calloc(1, sizeof(*tp));
        if (tp->e_nxt == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, "%s: calloc", __func__);

        return tp;
}

/*
 * Find the hash node that corresponds to the bytestring 'bs'
 * with length 'nlen'
 */

static struct bsnamemem *
lookup_bytestring(netdissect_options *ndo, const u_char *bs,
                  const unsigned int nlen)
{
        struct bsnamemem *tp;
        u_int i, j, k;

        if (nlen >= 6) {
                k = (bs[0] << 8) | bs[1];
                j = (bs[2] << 8) | bs[3];
                i = (bs[4] << 8) | bs[5];
        } else if (nlen >= 4) {
                k = (bs[0] << 8) | bs[1];
                j = (bs[2] << 8) | bs[3];
                i = 0;
        } else
                i = j = k = 0;

        tp = &bytestringtable[(i ^ j) & (HASHNAMESIZE-1)];
        while (tp->bs_nxt)
                if (nlen == tp->bs_nbytes &&
                    tp->bs_addr0 == i &&
                    tp->bs_addr1 == j &&
                    tp->bs_addr2 == k &&
                    memcmp((const char *)bs, (const char *)(tp->bs_bytes), nlen) == 0)
                        return tp;
                else
                        tp = tp->bs_nxt;

        tp->bs_addr0 = (u_short)i;
        tp->bs_addr1 = (u_short)j;
        tp->bs_addr2 = (u_short)k;

        tp->bs_bytes = (u_char *) calloc(1, nlen);
        if (tp->bs_bytes == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: calloc", __func__);

        memcpy(tp->bs_bytes, bs, nlen);
        tp->bs_nbytes = nlen;
        tp->bs_nxt = (struct bsnamemem *)calloc(1, sizeof(*tp));
        if (tp->bs_nxt == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: calloc", __func__);

        return tp;
}

/* Find the hash node that corresponds the NSAP 'nsap' */

static struct enamemem *
lookup_nsap(netdissect_options *ndo, const u_char *nsap,
            u_int nsap_length)
{
        u_int i, j, k;
        struct enamemem *tp;
        const u_char *ensap;

        if (nsap_length > 6) {
                ensap = nsap + nsap_length - 6;
                k = (ensap[0] << 8) | ensap[1];
                j = (ensap[2] << 8) | ensap[3];
                i = (ensap[4] << 8) | ensap[5];
        }
        else
                i = j = k = 0;

        tp = &nsaptable[(i ^ j) & (HASHNAMESIZE-1)];
        while (tp->e_nxt)
                if (nsap_length == tp->e_nsap[0] &&
                    tp->e_addr0 == i &&
                    tp->e_addr1 == j &&
                    tp->e_addr2 == k &&
                    memcmp((const char *)nsap,
                        (char *)&(tp->e_nsap[1]), nsap_length) == 0)
                        return tp;
                else
                        tp = tp->e_nxt;
        tp->e_addr0 = (u_short)i;
        tp->e_addr1 = (u_short)j;
        tp->e_addr2 = (u_short)k;
        tp->e_nsap = (u_char *)malloc(nsap_length + 1);
        if (tp->e_nsap == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, "%s: malloc", __func__);
        tp->e_nsap[0] = (u_char)nsap_length;    /* guaranteed < ISONSAP_MAX_LENGTH */
        memcpy((char *)&tp->e_nsap[1], (const char *)nsap, nsap_length);
        tp->e_nxt = (struct enamemem *)calloc(1, sizeof(*tp));
        if (tp->e_nxt == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, "%s: calloc", __func__);

        return tp;
}

/* Find the hash node that corresponds the protoid 'pi'. */

static struct protoidmem *
lookup_protoid(netdissect_options *ndo, const u_char *pi)
{
        u_int i, j;
        struct protoidmem *tp;

        /* 5 octets won't be aligned */
        i = (((pi[0] << 8) + pi[1]) << 8) + pi[2];
        j =   (pi[3] << 8) + pi[4];
        /* XXX should be endian-insensitive, but do big-endian testing  XXX */

        tp = &protoidtable[(i ^ j) & (HASHNAMESIZE-1)];
        while (tp->p_nxt)
                if (tp->p_oui == i && tp->p_proto == j)
                        return tp;
                else
                        tp = tp->p_nxt;
        tp->p_oui = i;
        tp->p_proto = (u_short)j;
        tp->p_nxt = (struct protoidmem *)calloc(1, sizeof(*tp));
        if (tp->p_nxt == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, "%s: calloc", __func__);

        return tp;
}

const char *
etheraddr_string(netdissect_options *ndo, const uint8_t *ep)
{
        int i;
        char *cp;
        struct enamemem *tp;
        int oui;
        char buf[BUFSIZE];

        tp = lookup_emem(ndo, ep);
        if (tp->e_name)
                return (tp->e_name);
#ifdef USE_ETHER_NTOHOST
        if (!ndo->ndo_nflag) {
                char buf2[BUFSIZE];

                if (ether_ntohost(buf2, (const struct ether_addr *)ep) == 0) {
                        tp->e_name = strdup(buf2);
                        if (tp->e_name == NULL)
                                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                        "%s: strdup(buf2)", __func__);
                        return (tp->e_name);
                }
        }
#endif
        cp = buf;
        oui = EXTRACT_BE_U_3(ep);
        cp = octet_to_hex(cp, *ep++);
        for (i = 5; --i >= 0;) {
                *cp++ = ':';
                cp = octet_to_hex(cp, *ep++);
        }

        if (!ndo->ndo_nflag) {
                snprintf(cp, BUFSIZE - (2 + 5*3), " (oui %s)",
                    tok2str(oui_values, "Unknown", oui));
        } else
                *cp = '\0';
        tp->e_name = strdup(buf);
        if (tp->e_name == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: strdup(buf)", __func__);
        return (tp->e_name);
}

const char *
le64addr_string(netdissect_options *ndo, const uint8_t *ep)
{
        const unsigned int len = 8;
        u_int i;
        char *cp;
        struct bsnamemem *tp;
        char buf[BUFSIZE];

        tp = lookup_bytestring(ndo, ep, len);
        if (tp->bs_name)
                return (tp->bs_name);

        cp = buf;
        for (i = len; i > 0 ; --i) {
                cp = octet_to_hex(cp, *(ep + i - 1));
                *cp++ = ':';
        }
        cp --;

        *cp = '\0';

        tp->bs_name = strdup(buf);
        if (tp->bs_name == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: strdup(buf)", __func__);

        return (tp->bs_name);
}

const char *
linkaddr_string(netdissect_options *ndo, const uint8_t *ep,
                const unsigned int type, const unsigned int len)
{
        u_int i;
        char *cp;
        struct bsnamemem *tp;

        if (len == 0)
                return ("<empty>");

        if (type == LINKADDR_ETHER && len == MAC_ADDR_LEN)
                return (etheraddr_string(ndo, ep));

        if (type == LINKADDR_FRELAY)
                return (q922_string(ndo, ep, len));

        tp = lookup_bytestring(ndo, ep, len);
        if (tp->bs_name)
                return (tp->bs_name);

        tp->bs_name = cp = (char *)malloc(len*3);
        if (tp->bs_name == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: malloc", __func__);
        cp = octet_to_hex(cp, *ep++);
        for (i = len-1; i > 0 ; --i) {
                *cp++ = ':';
                cp = octet_to_hex(cp, *ep++);
        }
        *cp = '\0';
        return (tp->bs_name);
}

#define ISONSAP_MAX_LENGTH 20
const char *
isonsap_string(netdissect_options *ndo, const uint8_t *nsap,
               u_int nsap_length)
{
        u_int nsap_idx;
        char *cp;
        struct enamemem *tp;

        if (nsap_length < 1 || nsap_length > ISONSAP_MAX_LENGTH)
                return ("isonsap_string: illegal length");

        tp = lookup_nsap(ndo, nsap, nsap_length);
        if (tp->e_name)
                return tp->e_name;

        tp->e_name = cp = (char *)malloc(sizeof("xx.xxxx.xxxx.xxxx.xxxx.xxxx.xxxx.xxxx.xxxx.xxxx.xx"));
        if (cp == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: malloc", __func__);

        for (nsap_idx = 0; nsap_idx < nsap_length; nsap_idx++) {
                cp = octet_to_hex(cp, *nsap++);
                if (((nsap_idx & 1) == 0) &&
                     (nsap_idx + 1 < nsap_length)) {
                        *cp++ = '.';
                }
        }
        *cp = '\0';
        return (tp->e_name);
}

const char *
tcpport_string(netdissect_options *ndo, u_short port)
{
        struct hnamemem *tp;
        uint32_t i = port;
        char buf[sizeof("00000")];

        for (tp = &tporttable[i & (HASHNAMESIZE-1)]; tp->nxt; tp = tp->nxt)
                if (tp->addr == i)
                        return (tp->name);

        tp->addr = i;
        tp->nxt = newhnamemem(ndo);

        (void)snprintf(buf, sizeof(buf), "%u", i);
        tp->name = strdup(buf);
        if (tp->name == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: strdup(buf)", __func__);
        return (tp->name);
}

const char *
udpport_string(netdissect_options *ndo, u_short port)
{
        struct hnamemem *tp;
        uint32_t i = port;
        char buf[sizeof("00000")];

        for (tp = &uporttable[i & (HASHNAMESIZE-1)]; tp->nxt; tp = tp->nxt)
                if (tp->addr == i)
                        return (tp->name);

        tp->addr = i;
        tp->nxt = newhnamemem(ndo);

        (void)snprintf(buf, sizeof(buf), "%u", i);
        tp->name = strdup(buf);
        if (tp->name == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: strdup(buf)", __func__);
        return (tp->name);
}

const char *
ipxsap_string(netdissect_options *ndo, u_short port)
{
        char *cp;
        struct hnamemem *tp;
        uint32_t i = port;
        char buf[sizeof("0000")];

        for (tp = &ipxsaptable[i & (HASHNAMESIZE-1)]; tp->nxt; tp = tp->nxt)
                if (tp->addr == i)
                        return (tp->name);

        tp->addr = i;
        tp->nxt = newhnamemem(ndo);

        cp = buf;
        port = ntohs(port);
        *cp++ = hex[port >> 12 & 0xf];
        *cp++ = hex[port >> 8 & 0xf];
        *cp++ = hex[port >> 4 & 0xf];
        *cp++ = hex[port & 0xf];
        *cp++ = '\0';
        tp->name = strdup(buf);
        if (tp->name == NULL)
                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                  "%s: strdup(buf)", __func__);
        return (tp->name);
}

static void
init_servarray(netdissect_options *ndo)
{
        struct servent *sv;
        struct hnamemem *table;
        int i;
        char buf[sizeof("0000000000")];

        while ((sv = getservent()) != NULL) {
                int port = ntohs(sv->s_port);
                i = port & (HASHNAMESIZE-1);
                if (strcmp(sv->s_proto, "tcp") == 0)
                        table = &tporttable[i];
                else if (strcmp(sv->s_proto, "udp") == 0)
                        table = &uporttable[i];
                else
                        continue;

                while (table->name)
                        table = table->nxt;
                if (ndo->ndo_nflag) {
                        (void)snprintf(buf, sizeof(buf), "%d", port);
                        table->name = strdup(buf);
                } else
                        table->name = strdup(sv->s_name);
                if (table->name == NULL)
                        (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                          "%s: strdup", __func__);

                table->addr = port;
                table->nxt = newhnamemem(ndo);
        }
        endservent();
}

static const struct eproto {
        const char *s;
        u_short p;
} eproto_db[] = {
        { "aarp", ETHERTYPE_AARP },
        { "arp", ETHERTYPE_ARP },
        { "atalk", ETHERTYPE_ATALK },
        { "decnet", ETHERTYPE_DN },
        { "ip", ETHERTYPE_IP },
        { "ip6", ETHERTYPE_IPV6 },
        { "lat", ETHERTYPE_LAT },
        { "loopback", ETHERTYPE_LOOPBACK },
        { "mopdl", ETHERTYPE_MOPDL },
        { "moprc", ETHERTYPE_MOPRC },
        { "rarp", ETHERTYPE_REVARP },
        { "sca", ETHERTYPE_SCA },
        { (char *)0, 0 }
};

static void
init_eprotoarray(netdissect_options *ndo)
{
        int i;
        struct hnamemem *table;

        for (i = 0; eproto_db[i].s; i++) {
                int j = htons(eproto_db[i].p) & (HASHNAMESIZE-1);
                table = &eprototable[j];
                while (table->name)
                        table = table->nxt;
                table->name = eproto_db[i].s;
                table->addr = htons(eproto_db[i].p);
                table->nxt = newhnamemem(ndo);
        }
}

static const struct protoidlist {
        const u_char protoid[5];
        const char *name;
} protoidlist[] = {
        {{ 0x00, 0x00, 0x0c, 0x01, 0x07 }, "CiscoMLS" },
        {{ 0x00, 0x00, 0x0c, 0x20, 0x00 }, "CiscoCDP" },
        {{ 0x00, 0x00, 0x0c, 0x20, 0x01 }, "CiscoCGMP" },
        {{ 0x00, 0x00, 0x0c, 0x20, 0x03 }, "CiscoVTP" },
        {{ 0x00, 0xe0, 0x2b, 0x00, 0xbb }, "ExtremeEDP" },
        {{ 0x00, 0x00, 0x00, 0x00, 0x00 }, NULL }
};

/*
 * SNAP proto IDs with org code 0:0:0 are actually encapsulated Ethernet
 * types.
 */
static void
init_protoidarray(netdissect_options *ndo)
{
        int i;
        struct protoidmem *tp;
        const struct protoidlist *pl;
        u_char protoid[5];

        protoid[0] = 0;
        protoid[1] = 0;
        protoid[2] = 0;
        for (i = 0; eproto_db[i].s; i++) {
                u_short etype = htons(eproto_db[i].p);

                memcpy((char *)&protoid[3], (char *)&etype, 2);
                tp = lookup_protoid(ndo, protoid);
                tp->p_name = strdup(eproto_db[i].s);
                if (tp->p_name == NULL)
                        (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                "%s: strdup(eproto_db[i].s)", __func__);
        }
        /* Hardwire some SNAP proto ID names */
        for (pl = protoidlist; pl->name != NULL; ++pl) {
                tp = lookup_protoid(ndo, pl->protoid);
                /* Don't override existing name */
                if (tp->p_name != NULL)
                        continue;

                tp->p_name = pl->name;
        }
}

static const struct etherlist {
        const nd_mac_addr addr;
        const char *name;
} etherlist[] = {
        {{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }, "Broadcast" },
        {{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, NULL }
};

/*
 * Initialize the ethers hash table.  We take two different approaches
 * depending on whether or not the system provides the ethers name
 * service.  If it does, we just wire in a few names at startup,
 * and etheraddr_string() fills in the table on demand.  If it doesn't,
 * then we suck in the entire /etc/ethers file at startup.  The idea
 * is that parsing the local file will be fast, but spinning through
 * all the ethers entries via NIS & next_etherent might be very slow.
 *
 * XXX pcap_next_etherent doesn't belong in the pcap interface, but
 * since the pcap module already does name-to-address translation,
 * it's already does most of the work for the ethernet address-to-name
 * translation, so we just pcap_next_etherent as a convenience.
 */
static void
init_etherarray(netdissect_options *ndo)
{
        const struct etherlist *el;
        struct enamemem *tp;
#ifdef USE_ETHER_NTOHOST
        char name[256];
#else
        struct pcap_etherent *ep;
        FILE *fp;

        /* Suck in entire ethers file */
        fp = fopen(PCAP_ETHERS_FILE, "r");
        if (fp != NULL) {
                while ((ep = pcap_next_etherent(fp)) != NULL) {
                        tp = lookup_emem(ndo, ep->addr);
                        tp->e_name = strdup(ep->name);
                        if (tp->e_name == NULL)
                                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                        "%s: strdup(ep->addr)", __func__);
                }
                (void)fclose(fp);
        }
#endif

        /* Hardwire some ethernet names */
        for (el = etherlist; el->name != NULL; ++el) {
                tp = lookup_emem(ndo, el->addr);
                /* Don't override existing name */
                if (tp->e_name != NULL)
                        continue;

#ifdef USE_ETHER_NTOHOST
                /*
                 * Use YP/NIS version of name if available.
                 */
                if (ether_ntohost(name, (const struct ether_addr *)el->addr) == 0) {
                        tp->e_name = strdup(name);
                        if (tp->e_name == NULL)
                                (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                        "%s: strdup(name)", __func__);
                        continue;
                }
#endif
                tp->e_name = el->name;
        }
}

static const struct ipxsap_ent {
        uint16_t        v;
        const char      *s;
} ipxsap_db[] = {
        { 0x0000, "Unknown" },
        { 0x0001, "User" },
        { 0x0002, "User Group" },
        { 0x0003, "PrintQueue" },
        { 0x0004, "FileServer" },
        { 0x0005, "JobServer" },
        { 0x0006, "Gateway" },
        { 0x0007, "PrintServer" },
        { 0x0008, "ArchiveQueue" },
        { 0x0009, "ArchiveServer" },
        { 0x000a, "JobQueue" },
        { 0x000b, "Administration" },
        { 0x000F, "Novell TI-RPC" },
        { 0x0017, "Diagnostics" },
        { 0x0020, "NetBIOS" },
        { 0x0021, "NAS SNA Gateway" },
        { 0x0023, "NACS AsyncGateway" },
        { 0x0024, "RemoteBridge/RoutingService" },
        { 0x0026, "BridgeServer" },
        { 0x0027, "TCP/IP Gateway" },
        { 0x0028, "Point-to-point X.25 BridgeServer" },
        { 0x0029, "3270 Gateway" },
        { 0x002a, "CHI Corp" },
        { 0x002c, "PC Chalkboard" },
        { 0x002d, "TimeSynchServer" },
        { 0x002e, "ARCserve5.0/PalindromeBackup" },
        { 0x0045, "DI3270 Gateway" },
        { 0x0047, "AdvertisingPrintServer" },
        { 0x004a, "NetBlazerModems" },
        { 0x004b, "BtrieveVAP" },
        { 0x004c, "NetwareSQL" },
        { 0x004d, "XtreeNetwork" },
        { 0x0050, "BtrieveVAP4.11" },
        { 0x0052, "QuickLink" },
        { 0x0053, "PrintQueueUser" },
        { 0x0058, "Multipoint X.25 Router" },
        { 0x0060, "STLB/NLM" },
        { 0x0064, "ARCserve" },
        { 0x0066, "ARCserve3.0" },
        { 0x0072, "WAN CopyUtility" },
        { 0x007a, "TES-NetwareVMS" },
        { 0x0092, "WATCOM Debugger/EmeraldTapeBackupServer" },
        { 0x0095, "DDA OBGYN" },
        { 0x0098, "NetwareAccessServer" },
        { 0x009a, "Netware for VMS II/NamedPipeServer" },
        { 0x009b, "NetwareAccessServer" },
        { 0x009e, "PortableNetwareServer/SunLinkNVT" },
        { 0x00a1, "PowerchuteAPC UPS" },
        { 0x00aa, "LAWserve" },
        { 0x00ac, "CompaqIDA StatusMonitor" },
        { 0x0100, "PIPE STAIL" },
        { 0x0102, "LAN ProtectBindery" },
        { 0x0103, "OracleDataBaseServer" },
        { 0x0107, "Netware386/RSPX RemoteConsole" },
        { 0x010f, "NovellSNA Gateway" },
        { 0x0111, "TestServer" },
        { 0x0112, "HP PrintServer" },
        { 0x0114, "CSA MUX" },
        { 0x0115, "CSA LCA" },
        { 0x0116, "CSA CM" },
        { 0x0117, "CSA SMA" },
        { 0x0118, "CSA DBA" },
        { 0x0119, "CSA NMA" },
        { 0x011a, "CSA SSA" },
        { 0x011b, "CSA STATUS" },
        { 0x011e, "CSA APPC" },
        { 0x0126, "SNA TEST SSA Profile" },
        { 0x012a, "CSA TRACE" },
        { 0x012b, "NetwareSAA" },
        { 0x012e, "IKARUS VirusScan" },
        { 0x0130, "CommunicationsExecutive" },
        { 0x0133, "NNS DomainServer/NetwareNamingServicesDomain" },
        { 0x0135, "NetwareNamingServicesProfile" },
        { 0x0137, "Netware386 PrintQueue/NNS PrintQueue" },
        { 0x0141, "LAN SpoolServer" },
        { 0x0152, "IRMALAN Gateway" },
        { 0x0154, "NamedPipeServer" },
        { 0x0166, "NetWareManagement" },
        { 0x0168, "Intel PICKIT CommServer/Intel CAS TalkServer" },
        { 0x0173, "Compaq" },
        { 0x0174, "Compaq SNMP Agent" },
        { 0x0175, "Compaq" },
        { 0x0180, "XTreeServer/XTreeTools" },
        { 0x018A, "NASI ServicesBroadcastServer" },
        { 0x01b0, "GARP Gateway" },
        { 0x01b1, "Binfview" },
        { 0x01bf, "IntelLanDeskManager" },
        { 0x01ca, "AXTEC" },
        { 0x01cb, "ShivaNetModem/E" },
        { 0x01cc, "ShivaLanRover/E" },
        { 0x01cd, "ShivaLanRover/T" },
        { 0x01ce, "ShivaUniversal" },
        { 0x01d8, "CastelleFAXPressServer" },
        { 0x01da, "CastelleLANPressPrintServer" },
        { 0x01dc, "CastelleFAX/Xerox7033 FaxServer/ExcelLanFax" },
        { 0x01f0, "LEGATO" },
        { 0x01f5, "LEGATO" },
        { 0x0233, "NMS Agent/NetwareManagementAgent" },
        { 0x0237, "NMS IPX Discovery/LANternReadWriteChannel" },
        { 0x0238, "NMS IP Discovery/LANternTrapAlarmChannel" },
        { 0x023a, "LANtern" },
        { 0x023c, "MAVERICK" },
        { 0x023f, "NovellSMDR" },
        { 0x024e, "NetwareConnect" },
        { 0x024f, "NASI ServerBroadcast Cisco" },
        { 0x026a, "NMS ServiceConsole" },
        { 0x026b, "TimeSynchronizationServer Netware 4.x" },
        { 0x0278, "DirectoryServer Netware 4.x" },
        { 0x027b, "NetwareManagementAgent" },
        { 0x0280, "Novell File and Printer Sharing Service for PC" },
        { 0x0304, "NovellSAA Gateway" },
        { 0x0308, "COM/VERMED" },
        { 0x030a, "GalacticommWorldgroupServer" },
        { 0x030c, "IntelNetport2/HP JetDirect/HP Quicksilver" },
        { 0x0320, "AttachmateGateway" },
        { 0x0327, "MicrosoftDiagnostiocs" },
        { 0x0328, "WATCOM SQL Server" },
        { 0x0335, "MultiTechSystems MultisynchCommServer" },
        { 0x0343, "Xylogics RemoteAccessServer/LANModem" },
        { 0x0355, "ArcadaBackupExec" },
        { 0x0358, "MSLCD1" },
        { 0x0361, "NETINELO" },
        { 0x037e, "Powerchute UPS Monitoring" },
        { 0x037f, "ViruSafeNotify" },
        { 0x0386, "HP Bridge" },
        { 0x0387, "HP Hub" },
        { 0x0394, "NetWare SAA Gateway" },
        { 0x039b, "LotusNotes" },
        { 0x03b7, "CertusAntiVirus" },
        { 0x03c4, "ARCserve4.0" },
        { 0x03c7, "LANspool3.5" },
        { 0x03d7, "LexmarkPrinterServer" },
        { 0x03d8, "LexmarkXLE PrinterServer" },
        { 0x03dd, "BanyanENS NetwareClient" },
        { 0x03de, "GuptaSequelBaseServer/NetWareSQL" },
        { 0x03e1, "UnivelUnixware" },
        { 0x03e4, "UnivelUnixware" },
        { 0x03fc, "IntelNetport" },
        { 0x03fd, "PrintServerQueue" },
        { 0x040A, "ipnServer" },
        { 0x040D, "LVERRMAN" },
        { 0x040E, "LVLIC" },
        { 0x0414, "NET Silicon (DPI)/Kyocera" },
        { 0x0429, "SiteLockVirus" },
        { 0x0432, "UFHELPR???" },
        { 0x0433, "Synoptics281xAdvancedSNMPAgent" },
        { 0x0444, "MicrosoftNT SNA Server" },
        { 0x0448, "Oracle" },
        { 0x044c, "ARCserve5.01" },
        { 0x0457, "CanonGP55" },
        { 0x045a, "QMS Printers" },
        { 0x045b, "DellSCSI Array" },
        { 0x0491, "NetBlazerModems" },
        { 0x04ac, "OnTimeScheduler" },
        { 0x04b0, "CD-Net" },
        { 0x0513, "EmulexNQA" },
        { 0x0520, "SiteLockChecks" },
        { 0x0529, "SiteLockChecks" },
        { 0x052d, "CitrixOS2 AppServer" },
        { 0x0535, "Tektronix" },
        { 0x0536, "Milan" },
        { 0x055d, "Attachmate SNA gateway" },
        { 0x056b, "IBM8235 ModemServer" },
        { 0x056c, "ShivaLanRover/E PLUS" },
        { 0x056d, "ShivaLanRover/T PLUS" },
        { 0x0580, "McAfeeNetShield" },
        { 0x05B8, "NLM to workstation communication (Revelation Software)" },
        { 0x05BA, "CompatibleSystemsRouters" },
        { 0x05BE, "CheyenneHierarchicalStorageManager" },
        { 0x0606, "JCWatermarkImaging" },
        { 0x060c, "AXISNetworkPrinter" },
        { 0x0610, "AdaptecSCSIManagement" },
        { 0x0621, "IBM AntiVirus" },
        { 0x0640, "Windows95 RemoteRegistryService" },
        { 0x064e, "MicrosoftIIS" },
        { 0x067b, "Microsoft Win95/98 File and Print Sharing for NetWare" },
        { 0x067c, "Microsoft Win95/98 File and Print Sharing for NetWare" },
        { 0x076C, "Xerox" },
        { 0x079b, "ShivaLanRover/E 115" },
        { 0x079c, "ShivaLanRover/T 115" },
        { 0x07B4, "CubixWorldDesk" },
        { 0x07c2, "Quarterdeck IWare Connect V2.x NLM" },
        { 0x07c1, "Quarterdeck IWare Connect V3.x NLM" },
        { 0x0810, "ELAN License Server Demo" },
        { 0x0824, "ShivaLanRoverAccessSwitch/E" },
        { 0x086a, "ISSC Collector" },
        { 0x087f, "ISSC DAS AgentAIX" },
        { 0x0880, "Intel Netport PRO" },
        { 0x0881, "Intel Netport PRO" },
        { 0x0b29, "SiteLock" },
        { 0x0c29, "SiteLockApplications" },
        { 0x0c2c, "LicensingServer" },
        { 0x2101, "PerformanceTechnologyInstantInternet" },
        { 0x2380, "LAI SiteLock" },
        { 0x238c, "MeetingMaker" },
        { 0x4808, "SiteLockServer/SiteLockMetering" },
        { 0x5555, "SiteLockUser" },
        { 0x6312, "Tapeware" },
        { 0x6f00, "RabbitGateway" },
        { 0x7703, "MODEM" },
        { 0x8002, "NetPortPrinters" },
        { 0x8008, "WordPerfectNetworkVersion" },
        { 0x85BE, "Cisco EIGRP" },
        { 0x8888, "WordPerfectNetworkVersion/QuickNetworkManagement" },
        { 0x9000, "McAfeeNetShield" },
        { 0x9604, "CSA-NT_MON" },
        { 0xb6a8, "OceanIsleReachoutRemoteControl" },
        { 0xf11f, "SiteLockMetering" },
        { 0xf1ff, "SiteLock" },
        { 0xf503, "Microsoft SQL Server" },
        { 0xF905, "IBM TimeAndPlace" },
        { 0xfbfb, "TopCallIII FaxServer" },
        { 0xffff, "AnyService/Wildcard" },
        { 0, (char *)0 }
};

static void
init_ipxsaparray(netdissect_options *ndo)
{
        int i;
        struct hnamemem *table;

        for (i = 0; ipxsap_db[i].s != NULL; i++) {
                u_int j = htons(ipxsap_db[i].v) & (HASHNAMESIZE-1);
                table = &ipxsaptable[j];
                while (table->name)
                        table = table->nxt;
                table->name = ipxsap_db[i].s;
                table->addr = htons(ipxsap_db[i].v);
                table->nxt = newhnamemem(ndo);
        }
}

/*
 * Initialize the address to name translation machinery.  We map all
 * non-local IP addresses to numeric addresses if ndo->ndo_fflag is true
 * (i.e., to prevent blocking on the nameserver).  localnet is the IP address
 * of the local network.  mask is its subnet mask.
 */
void
init_addrtoname(netdissect_options *ndo, uint32_t localnet, uint32_t mask)
{
        if (ndo->ndo_fflag) {
                f_localnet = localnet;
                f_netmask = mask;
        }
        if (ndo->ndo_nflag)
                /*
                 * Simplest way to suppress names.
                 */
                return;

        init_etherarray(ndo);
        init_servarray(ndo);
        init_eprotoarray(ndo);
        init_protoidarray(ndo);
        init_ipxsaparray(ndo);
}

const char *
dnaddr_string(netdissect_options *ndo, u_short dnaddr)
{
        struct hnamemem *tp;

        for (tp = &dnaddrtable[dnaddr & (HASHNAMESIZE-1)]; tp->nxt != NULL;
             tp = tp->nxt)
                if (tp->addr == dnaddr)
                        return (tp->name);

        tp->addr = dnaddr;
        tp->nxt = newhnamemem(ndo);
        tp->name = dnnum_string(ndo, dnaddr);

        return(tp->name);
}

/* Return a zero'ed hnamemem struct and cuts down on calloc() overhead */
struct hnamemem *
newhnamemem(netdissect_options *ndo)
{
        struct hnamemem *p;
        static struct hnamemem *ptr = NULL;
        static u_int num = 0;

        if (num  <= 0) {
                num = 64;
                ptr = (struct hnamemem *)calloc(num, sizeof (*ptr));
                if (ptr == NULL)
                        (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                          "%s: calloc", __func__);
        }
        --num;
        p = ptr++;
        return (p);
}

/* Return a zero'ed h6namemem struct and cuts down on calloc() overhead */
struct h6namemem *
newh6namemem(netdissect_options *ndo)
{
        struct h6namemem *p;
        static struct h6namemem *ptr = NULL;
        static u_int num = 0;

        if (num  <= 0) {
                num = 64;
                ptr = (struct h6namemem *)calloc(num, sizeof (*ptr));
                if (ptr == NULL)
                        (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
                                          "%s: calloc", __func__);
        }
        --num;
        p = ptr++;
        return (p);
}

/* Represent TCI part of the 802.1Q 4-octet tag as text. */
const char *
ieee8021q_tci_string(const uint16_t tci)
{
        static char buf[128];
        snprintf(buf, sizeof(buf), "vlan %u, p %u%s",
                 tci & 0xfff,
                 tci >> 13,
                 (tci & 0x1000) ? ", DEI" : "");
        return buf;
}