/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright (c) 2017, Joyent, Inc.
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <net/if.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/ip.h>
#include <netdb.h>
#include <string.h>
#include <signal.h>
#include <setjmp.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include "snoop.h"

static sigjmp_buf nisjmp;
static hrtime_t snoop_lastwarn;         /* Last time NS warning fired */
static unsigned snoop_warninter = 60;   /* Time in seconds between warnings */

#define MAXHASH 1024  /* must be a power of 2 */

#define SEPARATORS " \t\n"

struct hostdata {
        struct hostdata *h_next;
        char            *h_hostname;
        int             h_pktsout;
        int             h_pktsin;
};

struct hostdata4 {
        struct hostdata4        *h4_next;
        char            *h4_hostname;
        int             h4_pktsout;
        int             h4_pktsin;
        struct in_addr  h4_addr;
};

struct hostdata6 {
        struct hostdata6        *h6_next;
        char            *h6_hostname;
        int             h6_pktsout;
        int             h6_pktsin;
        struct in6_addr h6_addr;
};

static struct hostdata *addhost(int, const void *, const char *, char **);

static struct hostdata4 *h_table4[MAXHASH];
static struct hostdata6 *h_table6[MAXHASH];

#define iphash(e)  ((e) & (MAXHASH-1))

/* ARGSUSED */
static void
wakeup(int n)
{
        siglongjmp(nisjmp, 1);
}

extern char *inet_ntoa();

static void
snoop_nswarn(void)
{
        hrtime_t now = gethrtime();

        if (now - snoop_lastwarn >= snoop_warninter * NANOSEC) {
                snoop_lastwarn = now;
                (void) fprintf(stderr, "snoop: warning: packets captured, but "
                    "name service lookups are timing out. Use snoop -r to "
                    "disable name service lookups\n");
        }
}

static struct hostdata *
iplookup(struct in_addr ipaddr)
{
        register struct hostdata4 *h;
        struct hostent *hp = NULL;
        struct netent *np;
        int error_num;
        struct hostdata *retval;

        for (h = h_table4[iphash(ipaddr.s_addr)]; h; h = h->h4_next) {
                if (h->h4_addr.s_addr == ipaddr.s_addr)
                        return ((struct hostdata *)h);
        }

        /* not found.  Put it in */

        if (ipaddr.s_addr == htonl(INADDR_BROADCAST))
                return (addhost(AF_INET, &ipaddr, "BROADCAST", NULL));
        if (ipaddr.s_addr == htonl(INADDR_ANY))
                return (addhost(AF_INET, &ipaddr, "OLD-BROADCAST", NULL));

        /*
         * Set an alarm here so we don't get held up by
         * an unresponsive name server.
         * Give it 3 sec to do its work.
         */
        if (!rflg) {
                if (sigsetjmp(nisjmp, 1) == 0) {
                        (void) snoop_alarm(3, wakeup);
                        hp = getipnodebyaddr((char *)&ipaddr, sizeof (int),
                            AF_INET, &error_num);
                        if (hp == NULL && inet_lnaof(ipaddr) == 0) {
                                np = getnetbyaddr(inet_netof(ipaddr), AF_INET);
                                if (np)
                                        return (addhost(AF_INET, &ipaddr,
                                            np->n_name, np->n_aliases));
                        }
                        (void) snoop_alarm(0, wakeup);
                } else {
                        snoop_nswarn();
                }
        }

        retval = addhost(AF_INET, &ipaddr,
            hp ? hp->h_name : inet_ntoa(ipaddr),
            hp ? hp->h_aliases : NULL);
        if (hp != NULL)
                freehostent(hp);
        return (retval);
}

static struct hostdata *
ip6lookup(const struct in6_addr *ip6addr)
{
        struct hostdata6 *h;
        struct hostent *hp = NULL;
        int error_num;
        char addrstr[INET6_ADDRSTRLEN];
        char *addname;
        struct hostdata *retval;

        for (h = h_table6[iphash(((uint32_t *)ip6addr)[3])]; h;
            h = h->h6_next) {
                if (IN6_ARE_ADDR_EQUAL(&h->h6_addr, ip6addr))
                        return ((struct hostdata *)h);
        }

        /* not in the hash table, put it in */
        if (IN6_IS_ADDR_UNSPECIFIED(ip6addr))
                return (addhost(AF_INET6, ip6addr, "UNSPECIFIED", NULL));

        /*
         * Set an alarm here so we don't get held up by
         * an unresponsive name server.
         * Give it 3 sec to do its work.
         */
        if (!rflg) {
                if (sigsetjmp(nisjmp, 1) == 0) {
                        (void) snoop_alarm(3, wakeup);
                        hp = getipnodebyaddr(ip6addr, sizeof (struct in6_addr),
                            AF_INET6, &error_num);
                        (void) snoop_alarm(0, wakeup);
                } else {
                        snoop_nswarn();
                }
        } else {
                hp = NULL;
        }

        if (hp != NULL)
                addname = hp->h_name;
        else {
                (void) inet_ntop(AF_INET6, ip6addr, addrstr, INET6_ADDRSTRLEN);
                addname = addrstr;
        }

        retval = addhost(AF_INET6, ip6addr, addname, hp ? hp->h_aliases : NULL);
        if (hp != NULL)
                freehostent(hp);
        return (retval);
}

static struct hostdata *
addhost(int family, const void *ipaddr, const char *name, char **aliases)
{
        struct hostdata **hp, *n = NULL;
        extern FILE *namefile;
        int hashval;
        static char aname[128];
        char *np;
        static struct hostdata h;
        int ind;

        switch (family) {
        case AF_INET:
                n = (struct hostdata *)malloc(sizeof (struct hostdata4));
                if (n == NULL)
                        goto alloc_failed;

                memset(n, 0, sizeof (struct hostdata4));
                n->h_hostname = strdup(name);
                if (n->h_hostname == NULL)
                        goto alloc_failed;

                ((struct hostdata4 *)n)->h4_addr =
                    *(const struct in_addr *)ipaddr;
                hashval = ((struct in_addr *)ipaddr)->s_addr;
                hp = (struct hostdata **)&h_table4[iphash(hashval)];
                break;
        case AF_INET6:
                n = (struct hostdata *)malloc(sizeof (struct hostdata6));
                if (n == NULL)
                        goto alloc_failed;

                memset(n, 0, sizeof (struct hostdata6));
                n->h_hostname = strdup(name);
                if (n->h_hostname == NULL)
                        goto alloc_failed;

                memcpy(&((struct hostdata6 *)n)->h6_addr, ipaddr,
                    sizeof (struct in6_addr));
                hashval = ((const int *)ipaddr)[3];
                hp = (struct hostdata **)&h_table6[iphash(hashval)];
                break;
        default:
                fprintf(stderr, "snoop: ERROR: Unknown address family: %d",
                    family);
                exit(1);
        }

        n->h_next = *hp;
        *hp = n;

        if (namefile != NULL) {
                if (family == AF_INET) {
                        np = inet_ntoa(*(const struct in_addr *)ipaddr);
                        if (np) {
                                (void) fprintf(namefile, "%s\t%s", np, name);
                                if (aliases) {
                                        for (ind = 0;
                                            aliases[ind] != NULL;
                                            ind++) {
                                                (void) fprintf(namefile, " %s",
                                                    aliases[ind]);
                                        }
                                }
                                (void) fprintf(namefile, "\n");
                        }
                } else if (family == AF_INET6) {
                        np = (char *)inet_ntop(AF_INET6, (void *)ipaddr, aname,
                            sizeof (aname));
                        if (np) {
                                (void) fprintf(namefile, "%s\t%s", np, name);
                                if (aliases) {
                                        for (ind = 0;
                                            aliases[ind] != NULL;
                                            ind++) {
                                                (void) fprintf(namefile, " %s",
                                                    aliases[ind]);
                                        }
                                }
                                (void) fprintf(namefile, "\n");
                        }
                } else {
                        (void) fprintf(stderr, "addhost: unknown family %d\n",
                            family);
                }
        }
        return (n);

alloc_failed:
        if (n)
                free(n);
        (void) fprintf(stderr, "addhost: no mem\n");

        aname[0] = '\0';
        memset(&h, 0, sizeof (struct hostdata));
        h.h_hostname = aname;
        return (&h);
}

char *
addrtoname(int family, const void *ipaddr)
{
        switch (family) {
        case AF_INET:
                return (iplookup(*(const struct in_addr *)ipaddr)->h_hostname);
        case AF_INET6:
                return (ip6lookup((const struct in6_addr *)ipaddr)->h_hostname);
        }
        (void) fprintf(stderr, "snoop: ERROR: unknown address family: %d\n",
            family);
        exit(1);
        /* NOTREACHED */
}

void
load_names(char *fname)
{
        char buf[1024];
        char *addr, *name, *alias;
        FILE *f;
        unsigned int addrv4;
        struct in6_addr addrv6;
        int family;
        void *naddr;

        (void) fprintf(stderr, "Loading name file %s\n", fname);
        f = fopen(fname, "r");
        if (f == NULL) {
                perror(fname);
                return;
        }

        while (fgets(buf, 1024, f) != NULL) {
                addr = strtok(buf, SEPARATORS);
                if (addr == NULL || *addr == '#')
                        continue;
                if (inet_pton(AF_INET6, addr, (void *)&addrv6) == 1) {
                        family = AF_INET6;
                        naddr = (void *)&addrv6;
                } else if ((addrv4 = inet_addr(addr)) != (ulong_t)-1) {
                        family = AF_INET;
                        naddr = (void *)&addrv4;
                }
                name = strtok(NULL, SEPARATORS);
                if (name == NULL)
                        continue;
                while ((alias = strtok(NULL, SEPARATORS)) != NULL &&
                    (*alias != '#')) {
                        (void) addhost(family, naddr, alias, NULL);
                }
                (void) addhost(family, naddr, name, NULL);
                /* Note: certain addresses such as broadcast are skipped */
        }

        (void) fclose(f);
}

/*
 * lgetipnodebyname: looks up hostname in cached address data. This allows
 * filtering on hostnames from the .names file to work properly, and
 * avoids name clashes between domains. Note that only the first of the
 * ipv4, ipv6, or v4mapped address will be returned, because the
 * cache does not contain information on multi-homed hosts.
 */
/*ARGSUSED*/
struct hostent *
lgetipnodebyname(const char *name, int af, int flags, int *error_num)
{
        int i;
        struct hostdata4 *h;
        struct hostdata6 *h6;
        static struct hostent he;               /* host entry */
        static struct in6_addr h46_addr[MAXADDRS];      /* v4mapped address */
        static char h_name[MAXHOSTNAMELEN];     /* hostname */
        static char *list[MAXADDRS];            /* addr_list array */
        struct hostent *hp = &he;
        int ind;

        (void) memset((char *)hp, 0, sizeof (struct hostent));
        hp->h_name = h_name;
        h_name[0] = '\0';
        strcpy(h_name, name);

        hp->h_addrtype = AF_INET6;

        hp->h_addr_list = list;
        for (i = 0; i < MAXADDRS; i++)
                hp->h_addr_list[i] = NULL;
        ind = 0;

        /* ipv6 lookup */
        if (af == AF_INET6) {
                hp->h_length = sizeof (struct in6_addr);
                for (i = 0; i < MAXHASH; i++) {
                        for (h6 = h_table6[i]; h6; h6 = h6->h6_next) {
                                if (strcmp(name, h6->h6_hostname) == 0) {
                                        if (ind >= MAXADDRS - 1) {
                                                /* too many addresses */
                                                return (hp);
                                        }
                                        /* found ipv6 addr */
                                        hp->h_addr_list[ind] =
                                            (char *)&h6->h6_addr;
                                        ind++;
                                }
                        }
                }
        }
        /* ipv4 or v4mapped lookup */
        if (af == AF_INET || (flags & AI_ALL)) {
                for (i = 0; i < MAXHASH; i++) {
                        for (h = h_table4[i]; h; h = h->h4_next) {
                                if (strcmp(name, h->h4_hostname) == 0) {
                                        if (ind >= MAXADDRS - 1) {
                                                /* too many addresses */
                                                return (hp);
                                        }
                                        if (af == AF_INET) {
                                                /* found ipv4 addr */
                                                hp->h_addrtype = AF_INET;
                                                hp->h_length =
                                                    sizeof (struct in_addr);
                                                hp->h_addr_list[ind] =
                                                    (char *)&h->h4_addr;
                                                ind++;
                                        } else {
                                                /* found v4mapped addr */
                                                hp->h_length =
                                                    sizeof (struct in6_addr);
                                                hp->h_addr_list[ind] =
                                                    (char *)&h46_addr[ind];
                                                IN6_INADDR_TO_V4MAPPED(
                                                    &h->h4_addr,
                                                    &h46_addr[ind]);
                                                ind++;
                                        }
                                }
                        }
                }
        }
        return (ind > 0 ? hp : NULL);
}