[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
 */
#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /tcpdump/master/tcpdump/addrtoname.c,v 1.85 2001-11-15 08:06:37 itojun Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>

struct mbuf;
struct rtentry;
#include <net/if.h>

#include <netinet/in.h>
#ifdef HAVE_NETINET_IF_ETHER_H
#include <netinet/if_ether.h>
#endif

#include <arpa/inet.h>

#include <ctype.h>
#include <netdb.h>
#include <pcap.h>
#include <pcap-namedb.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#include "interface.h"
#include "addrtoname.h"
#include "llc.h"
#include "setsignal.h"

/*
 * hash tables for whatever-to-name translations
 *
 * XXX there has to be error checks against strdup(3) failure
 */

#define HASHNAMESIZE 4096

struct hnamemem {
        u_int32_t addr;
        const char *name;
        struct hnamemem *nxt;
};

struct hnamemem hnametable[HASHNAMESIZE];
struct hnamemem tporttable[HASHNAMESIZE];
struct hnamemem uporttable[HASHNAMESIZE];
struct hnamemem eprototable[HASHNAMESIZE];
struct hnamemem dnaddrtable[HASHNAMESIZE];
struct hnamemem llcsaptable[HASHNAMESIZE];

#ifdef INET6
struct h6namemem {
        struct in6_addr addr;
        char *name;
        struct h6namemem *nxt;
};

struct h6namemem h6nametable[HASHNAMESIZE];
#endif /* INET6 */

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[] */
#define e_bs e_nsap                     /* for bytestringtable */
        struct enamemem *e_nxt;
};

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

struct protoidmem {
        u_int32_t p_oui;
        u_short p_proto;
        const char *p_name;
        struct protoidmem *p_nxt;
};

struct protoidmem protoidtable[HASHNAMESIZE];

/*
 * A faster replacement for inet_ntoa().
 */
const char *
intoa(u_int32_t addr)
{
        register char *cp;
        register u_int byte;
        register int n;
        static char buf[sizeof(".xxx.xxx.xxx.xxx")];

        NTOHL(addr);
        cp = &buf[sizeof buf];
        *--cp = '\0';

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

        return cp + 1;
}

static u_int32_t f_netmask;
static u_int32_t f_localnet;
static u_int32_t netmask;

/*
 * Return a name for the IP address pointed to by ap.  This address
 * is assumed to be in network byte order.
 */
const char *
getname(const u_char *ap)
{
        register struct hostent *hp;
        u_int32_t addr;
        static struct hnamemem *p;              /* static for longjmp() */

        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();

        /*
         * Only print names when:
         *      (1) -n was not given.
         *      (2) Address is foreign and -f was given. (If -f was not
         *          give, f_netmask and f_local are 0 and the test
         *          evaluates to true)
         *      (3) -a was given or the host portion is not all ones
         *          nor all zeros (i.e. not a network or broadcast address)
         */
        if (!nflag &&
            (addr & f_netmask) == f_localnet &&
            (aflag ||
            !((addr & ~netmask) == 0 || (addr | netmask) == 0xffffffff))) {
                hp = gethostbyaddr((char *)&addr, 4, AF_INET);
                if (hp) {
                        char *dotp;

                        p->name = strdup(hp->h_name);
                        if (Nflag) {
                                /* Remove domain qualifications */
                                dotp = strchr(p->name, '.');
                                if (dotp)
                                        *dotp = '\0';
                        }
                        return (p->name);
                }
        }
        p->name = strdup(intoa(addr));
        return (p->name);
}

#ifdef INET6
/*
 * Return a name for the IP6 address pointed to by ap.  This address
 * is assumed to be in network byte order.
 */
const char *
getname6(const u_char *ap)
{
        register struct hostent *hp;
        struct in6_addr addr;
        static struct h6namemem *p;             /* static for longjmp() */
        register const char *cp;
        char ntop_buf[INET6_ADDRSTRLEN];

        memcpy(&addr, ap, sizeof(addr));
        p = &h6nametable[*(u_int16_t *)&addr.s6_addr[14] & (HASHNAMESIZE-1)];
        for (; p->nxt; p = p->nxt) {
                if (memcmp(&p->addr, &addr, sizeof(addr)) == 0)
                        return (p->name);
        }
        p->addr = addr;
        p->nxt = newh6namemem();

        /*
         * Only print names when:
         *      (1) -n was not given.
         *      (2) Address is foreign and -f was given. (If -f was not
         *          give, f_netmask and f_local are 0 and the test
         *          evaluates to true)
         *      (3) -a was given or the host portion is not all ones
         *          nor all zeros (i.e. not a network or broadcast address)
         */
        if (!nflag
#if 0
        &&
            (addr & f_netmask) == f_localnet &&
            (aflag ||
            !((addr & ~netmask) == 0 || (addr | netmask) == 0xffffffff))
#endif
            ) {
                hp = gethostbyaddr((char *)&addr, sizeof(addr), AF_INET6);
                if (hp) {
                        char *dotp;

                        p->name = strdup(hp->h_name);
                        if (Nflag) {
                                /* Remove domain qualifications */
                                dotp = strchr(p->name, '.');
                                if (dotp)
                                        *dotp = '\0';
                        }
                        return (p->name);
                }
        }
        cp = inet_ntop(AF_INET6, &addr, ntop_buf, sizeof(ntop_buf));
        p->name = strdup(cp);
        return (p->name);
}
#endif /* INET6 */

static char hex[] = "0123456789abcdef";


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

static inline struct enamemem *
lookup_emem(const u_char *ep)
{
        register 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 = i;
        tp->e_addr1 = j;
        tp->e_addr2 = k;
        tp->e_nxt = (struct enamemem *)calloc(1, sizeof(*tp));
        if (tp->e_nxt == NULL)
                error("lookup_emem: calloc");

        return tp;
}

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

static inline struct enamemem *
lookup_bytestring(register const u_char *bs, const unsigned int nlen)
{
        struct enamemem *tp;
        register 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->e_nxt)
                if (tp->e_addr0 == i &&
                    tp->e_addr1 == j &&
                    tp->e_addr2 == k &&
                    memcmp((const char *)bs, (const char *)(tp->e_bs), nlen) == 0)
                        return tp;
                else
                        tp = tp->e_nxt;

        tp->e_addr0 = i;
        tp->e_addr1 = j;
        tp->e_addr2 = k;

        tp->e_bs = (u_char *) calloc(1, nlen + 1);
        memcpy(tp->e_bs, bs, nlen);
        tp->e_nxt = (struct enamemem *)calloc(1, sizeof(*tp));
        if (tp->e_nxt == NULL)
                error("lookup_bytestring: calloc");

        return tp;
}

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

static inline struct enamemem *
lookup_nsap(register const u_char *nsap)
{
        register u_int i, j, k;
        unsigned int nlen = *nsap;
        struct enamemem *tp;
        const u_char *ensap = nsap + nlen - 6;

        if (nlen > 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 (tp->e_addr0 == i &&
                    tp->e_addr1 == j &&
                    tp->e_addr2 == k &&
                    tp->e_nsap[0] == nlen &&
                    memcmp((const char *)&(nsap[1]),
                        (char *)&(tp->e_nsap[1]), nlen) == 0)
                        return tp;
                else
                        tp = tp->e_nxt;
        tp->e_addr0 = i;
        tp->e_addr1 = j;
        tp->e_addr2 = k;
        tp->e_nsap = (u_char *)malloc(nlen + 1);
        if (tp->e_nsap == NULL)
                error("lookup_nsap: malloc");
        memcpy((char *)tp->e_nsap, (const char *)nsap, nlen + 1);
        tp->e_nxt = (struct enamemem *)calloc(1, sizeof(*tp));
        if (tp->e_nxt == NULL)
                error("lookup_nsap: calloc");

        return tp;
}

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

static inline struct protoidmem *
lookup_protoid(const u_char *pi)
{
        register 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 = j;
        tp->p_nxt = (struct protoidmem *)calloc(1, sizeof(*tp));
        if (tp->p_nxt == NULL)
                error("lookup_protoid: calloc");

        return tp;
}

const char *
etheraddr_string(register const u_char *ep)
{
        register u_int i, j;
        register char *cp;
        register struct enamemem *tp;
        char buf[sizeof("00:00:00:00:00:00")];

        tp = lookup_emem(ep);
        if (tp->e_name)
                return (tp->e_name);
#ifdef USE_ETHER_NTOHOST
        if (!nflag) {
                char buf[128];
                if (ether_ntohost(buf, (const struct ether_addr *)ep) == 0) {
                        tp->e_name = strdup(buf);
                        return (tp->e_name);
                }
        }
#endif
        cp = buf;
        if ((j = *ep >> 4) != 0)
                *cp++ = hex[j];
        *cp++ = hex[*ep++ & 0xf];
        for (i = 5; (int)--i >= 0;) {
                *cp++ = ':';
                if ((j = *ep >> 4) != 0)
                        *cp++ = hex[j];
                *cp++ = hex[*ep++ & 0xf];
        }
        *cp = '\0';
        tp->e_name = strdup(buf);
        return (tp->e_name);
}

const char *
linkaddr_string(const u_char *ep, const unsigned int len)
{
        register u_int i, j;
        register char *cp;
        register struct enamemem *tp;

        if (len == 6)   /* XXX not totally correct... */
                return etheraddr_string(ep);
        
        tp = lookup_bytestring(ep, len);
        if (tp->e_name)
                return (tp->e_name);

        tp->e_name = cp = (char *)malloc(len*3);
        if (tp->e_name == NULL)
                error("linkaddr_string: malloc");
        if ((j = *ep >> 4) != 0)
                *cp++ = hex[j];
        *cp++ = hex[*ep++ & 0xf];
        for (i = len-1; i > 0 ; --i) {
                *cp++ = ':';
                if ((j = *ep >> 4) != 0)
                        *cp++ = hex[j];
                *cp++ = hex[*ep++ & 0xf];
        }
        *cp = '\0';
        return (tp->e_name);
}

const char *
etherproto_string(u_short port)
{
        register char *cp;
        register struct hnamemem *tp;
        register u_int32_t i = port;
        char buf[sizeof("0000")];

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

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

        cp = buf;
        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);
        return (tp->name);
}

const char *
protoid_string(register const u_char *pi)
{
        register u_int i, j;
        register char *cp;
        register struct protoidmem *tp;
        char buf[sizeof("00:00:00:00:00")];

        tp = lookup_protoid(pi);
        if (tp->p_name)
                return tp->p_name;

        cp = buf;
        if ((j = *pi >> 4) != 0)
                *cp++ = hex[j];
        *cp++ = hex[*pi++ & 0xf];
        for (i = 4; (int)--i >= 0;) {
                *cp++ = ':';
                if ((j = *pi >> 4) != 0)
                        *cp++ = hex[j];
                *cp++ = hex[*pi++ & 0xf];
        }
        *cp = '\0';
        tp->p_name = strdup(buf);
        return (tp->p_name);
}

const char *
llcsap_string(u_char sap)
{
        register struct hnamemem *tp;
        register u_int32_t i = sap;
        char buf[sizeof("sap 00")];

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

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

        snprintf(buf, sizeof(buf), "sap %02x", sap & 0xff);
        tp->name = strdup(buf);
        return (tp->name);
}

const char *
isonsap_string(const u_char *nsap)
{
        register u_int i, nlen = nsap[0];
        register char *cp;
        register struct enamemem *tp;

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

        tp->e_name = cp = (char *)malloc(nlen * 2 + 2);
        if (cp == NULL)
                error("isonsap_string: malloc");

        nsap++;
        *cp++ = '/';
        for (i = nlen; (int)--i >= 0;) {
                *cp++ = hex[*nsap >> 4];
                *cp++ = hex[*nsap++ & 0xf];
        }
        *cp = '\0';
        return (tp->e_name);
}

const char *
tcpport_string(u_short port)
{
        register struct hnamemem *tp;
        register u_int32_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();

        (void)snprintf(buf, sizeof(buf), "%u", i);
        tp->name = strdup(buf);
        return (tp->name);
}

const char *
udpport_string(register u_short port)
{
        register struct hnamemem *tp;
        register u_int32_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();

        (void)snprintf(buf, sizeof(buf), "%u", i);
        tp->name = strdup(buf);
        return (tp->name);
}

static void
init_servarray(void)
{
        struct servent *sv;
        register struct hnamemem *table;
        register 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 (nflag) {
                        (void)snprintf(buf, sizeof(buf), "%d", port);
                        table->name = strdup(buf);
                } else
                        table->name = strdup(sv->s_name);
                table->addr = port;
                table->nxt = newhnamemem();
        }
        endservent();
}

/*XXX from libbpfc.a */
extern struct eproto {
        char *s;
        u_short p;
} eproto_db[];

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

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

static 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(void)
{
        register int i;
        register struct protoidmem *tp;
        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(protoid);
                tp->p_name = strdup(eproto_db[i].s);
        }
        /* Hardwire some SNAP proto ID names */
        for (pl = protoidlist; pl->name != NULL; ++pl) {
                tp = lookup_protoid(pl->protoid);
                /* Don't override existing name */
                if (tp->p_name != NULL)
                        continue;

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

static struct etherlist {
        const u_char addr[6];
        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(void)
{
        register struct etherlist *el;
        register struct enamemem *tp;
#ifdef USE_ETHER_NTOHOST
        char name[256];
#else
        register struct pcap_etherent *ep;
        register 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(ep->addr);
                        tp->e_name = strdup(ep->name);
                }
                (void)fclose(fp);
        }
#endif

        /* Hardwire some ethernet names */
        for (el = etherlist; el->name != NULL; ++el) {
                tp = lookup_emem(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);
                        continue;
                }
#endif
                tp->e_name = el->name;
        }
}

static struct tok llcsap_db[] = {
        { LLCSAP_NULL,          "null" },
        { LLCSAP_8021B_I,       "802.1b-gsap" },
        { LLCSAP_8021B_G,       "802.1b-isap" },
        { LLCSAP_IP,            "ip-sap" },
        { LLCSAP_PROWAYNM,      "proway-nm" },
        { LLCSAP_8021D,         "802.1d" },
        { LLCSAP_RS511,         "eia-rs511" },
        { LLCSAP_ISO8208,       "x.25/llc2" },
        { LLCSAP_PROWAY,        "proway" },
        { LLCSAP_SNAP,          "snap" },
        { LLCSAP_IPX,           "IPX" },
        { LLCSAP_NETBEUI,       "netbeui" },
        { LLCSAP_ISONS,         "iso-clns" },
        { LLCSAP_GLOBAL,        "global" },
        { 0,                    NULL }
};

static void
init_llcsaparray(void)
{
        register int i;
        register struct hnamemem *table;

        for (i = 0; llcsap_db[i].s != NULL; i++) {
                table = &llcsaptable[llcsap_db[i].v];
                while (table->name)
                        table = table->nxt;
                table->name = llcsap_db[i].s;
                table->addr = llcsap_db[i].v;
                table->nxt = newhnamemem();
        }
}

/*
 * Initialize the address to name translation machinery.  We map all
 * non-local IP addresses to numeric addresses if 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(u_int32_t localnet, u_int32_t mask)
{
        netmask = mask;
        if (fflag) {
                f_localnet = localnet;
                f_netmask = mask;
        }
        if (nflag)
                /*
                 * Simplest way to suppress names.
                 */
                return;

        init_etherarray();
        init_servarray();
        init_eprotoarray();
        init_llcsaparray();
        init_protoidarray();
}

const char *
dnaddr_string(u_short dnaddr)
{
        register struct hnamemem *tp;

        for (tp = &dnaddrtable[dnaddr & (HASHNAMESIZE-1)]; tp->nxt != 0;
             tp = tp->nxt)
                if (tp->addr == dnaddr)
                        return (tp->name);

        tp->addr = dnaddr;
        tp->nxt = newhnamemem();
        if (nflag)
                tp->name = dnnum_string(dnaddr);
        else
                tp->name = dnname_string(dnaddr);

        return(tp->name);
}

/* Return a zero'ed hnamemem struct and cuts down on calloc() overhead */
struct hnamemem *
newhnamemem(void)
{
        register 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)
                        error("newhnamemem: calloc");
        }
        --num;
        p = ptr++;
        return (p);
}

#ifdef INET6
/* Return a zero'ed h6namemem struct and cuts down on calloc() overhead */
struct h6namemem *
newh6namemem(void)
{
        register 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)
                        error("newh6namemem: calloc");
        }
        --num;
        p = ptr++;
        return (p);
}
#endif /* INET6 */