/*      $OpenBSD: print-icmp.c,v 1.27 2021/12/01 18:28:46 deraadt Exp $ */

/*
 * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
 *      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 <net/if.h>

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

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

#include "interface.h"
#include "addrtoname.h"
#include "extract.h"                    /* must come after interface.h */

/* rfc1700 */
#ifndef ICMP_UNREACH_NET_UNKNOWN
#define ICMP_UNREACH_NET_UNKNOWN        6       /* destination net unknown */
#endif
#ifndef ICMP_UNREACH_HOST_UNKNOWN
#define ICMP_UNREACH_HOST_UNKNOWN       7       /* destination host unknown */
#endif
#ifndef ICMP_UNREACH_ISOLATED
#define ICMP_UNREACH_ISOLATED           8       /* source host isolated */
#endif
#ifndef ICMP_UNREACH_NET_PROHIB
#define ICMP_UNREACH_NET_PROHIB         9       /* admin prohibited net */
#endif
#ifndef ICMP_UNREACH_HOST_PROHIB
#define ICMP_UNREACH_HOST_PROHIB        10      /* admin prohibited host */
#endif
#ifndef ICMP_UNREACH_TOSNET
#define ICMP_UNREACH_TOSNET             11      /* tos prohibited net */
#endif
#ifndef ICMP_UNREACH_TOSHOST
#define ICMP_UNREACH_TOSHOST            12      /* tos prohibited host */
#endif

/* rfc1716 */
#ifndef ICMP_UNREACH_FILTER_PROHIB
#define ICMP_UNREACH_FILTER_PROHIB      13      /* admin prohibited filter */
#endif
#ifndef ICMP_UNREACH_HOST_PRECEDENCE
#define ICMP_UNREACH_HOST_PRECEDENCE    14      /* host precedence violation */
#endif
#ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
#define ICMP_UNREACH_PRECEDENCE_CUTOFF  15      /* precedence cutoff */
#endif

/* rfc1256 */
#ifndef ICMP_ROUTERADVERT
#define ICMP_ROUTERADVERT               9       /* router advertisement */
#endif
#ifndef ICMP_ROUTERSOLICIT
#define ICMP_ROUTERSOLICIT              10      /* router solicitation */
#endif

#define ICMP_INFOTYPE(type) \
    ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
    (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
    (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
    (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
    (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)

/* Most of the icmp types */
static struct tok icmp2str[] = {
        { ICMP_ECHOREPLY,               "echo reply" },
        { ICMP_SOURCEQUENCH,            "source quench" },
        { ICMP_ECHO,                    "echo request" },
        { ICMP_ROUTERSOLICIT,           "router solicitation" },
        { ICMP_TSTAMP,                  "time stamp request" },
        { ICMP_TSTAMPREPLY,             "time stamp reply" },
        { ICMP_IREQ,                    "information request" },
        { ICMP_IREQREPLY,               "information reply" },
        { ICMP_MASKREQ,                 "address mask request" },
        { 0,                            NULL }
};

/* Formats for most of the ICMP_UNREACH codes */
static struct tok unreach2str[] = {
        { ICMP_UNREACH_NET,             "net %s unreachable" },
        { ICMP_UNREACH_HOST,            "host %s unreachable" },
        { ICMP_UNREACH_SRCFAIL,
            "%s unreachable - source route failed" },
        { ICMP_UNREACH_NET_UNKNOWN,     "net %s unreachable - unknown" },
        { ICMP_UNREACH_HOST_UNKNOWN,    "host %s unreachable - unknown" },
        { ICMP_UNREACH_ISOLATED,
            "%s unreachable - source host isolated" },
        { ICMP_UNREACH_NET_PROHIB,
            "net %s unreachable - admin prohibited" },
        { ICMP_UNREACH_HOST_PROHIB,
            "host %s unreachable - admin prohibited" },
        { ICMP_UNREACH_TOSNET,
            "net %s unreachable - tos prohibited" },
        { ICMP_UNREACH_TOSHOST,
            "host %s unreachable - tos prohibited" },
        { ICMP_UNREACH_FILTER_PROHIB,
            "host %s unreachable - admin prohibited filter" },
        { ICMP_UNREACH_HOST_PRECEDENCE,
            "host %s unreachable - host precedence violation" },
        { ICMP_UNREACH_PRECEDENCE_CUTOFF,
            "host %s unreachable - precedence cutoff" },
        { 0,                            NULL }
};

/* Formats for the ICMP_REDIRECT codes */
static struct tok type2str[] = {
        { ICMP_REDIRECT_NET,            "redirect %s to net %s" },
        { ICMP_REDIRECT_HOST,           "redirect %s to host %s" },
        { ICMP_REDIRECT_TOSNET,         "redirect-tos %s to net %s" },
        { ICMP_REDIRECT_TOSHOST,        "redirect-tos %s to net %s" },
        { 0,                            NULL }
};

/* rfc1191 */
struct mtu_discovery {
        short unused;
        short nexthopmtu;
};

/* rfc1256 */
struct ih_rdiscovery {
        u_char ird_addrnum;
        u_char ird_addrsiz;
        u_short ird_lifetime;
};

struct id_rdiscovery {
        u_int32_t ird_addr;
        u_int32_t ird_pref;
};

void
icmp_print(const u_char *bp, u_int length, const u_char *bp2)
{
        const struct icmp *dp;
        const struct ip *ip;
        const char *str, *fmt;
        const struct ip *oip;
        const struct udphdr *ouh;
        u_int hlen, dport, mtu;
        char buf[HOST_NAME_MAX+1+256];
        char buf2[HOST_NAME_MAX+1+256];

        dp = (struct icmp *)bp;
        ip = (struct ip *)bp2;
        str = buf;

        printf("%s > %s: ",
            ipaddr_string(&ip->ip_src),
            ipaddr_string(&ip->ip_dst));

        TCHECK(dp->icmp_code);
        if (qflag) 
                (void) snprintf(buf, sizeof buf, "%u %u", dp->icmp_type,
                    dp->icmp_code);
        else switch (dp->icmp_type) {

        case ICMP_ECHOREPLY:
        case ICMP_ECHO:
                if (vflag) {
                        TCHECK(dp->icmp_seq);
                        (void)snprintf(buf, sizeof buf,
                                       "echo %s (id:%04x seq:%u)",
                                       (dp->icmp_type == ICMP_ECHO)?
                                       "request": "reply",
                                       ntohs(dp->icmp_id),
                                       ntohs(dp->icmp_seq));
                } else
                        str = tok2str(icmp2str, "type-#%u", dp->icmp_type);
                break;

        case ICMP_UNREACH:
                TCHECK(dp->icmp_ip.ip_dst);
                switch (dp->icmp_code) {

                case ICMP_UNREACH_PROTOCOL:
                        TCHECK(dp->icmp_ip.ip_p);
                        (void)snprintf(buf, sizeof buf,
                                       "%s protocol %u unreachable",
                                       ipaddr_string(&dp->icmp_ip.ip_dst),
                                       dp->icmp_ip.ip_p);
                        break;

                case ICMP_UNREACH_PORT:
                        TCHECK(dp->icmp_ip.ip_p);
                        oip = &dp->icmp_ip;
                        hlen = oip->ip_hl * 4;
                        ouh = (struct udphdr *)(((u_char *)oip) + hlen);
                        TCHECK(ouh->uh_dport);
                        dport = ntohs(ouh->uh_dport);
                        switch (oip->ip_p) {

                        case IPPROTO_TCP:
                                (void)snprintf(buf, sizeof buf,
                                        "%s tcp port %s unreachable",
                                        ipaddr_string(&oip->ip_dst),
                                        tcpport_string(dport));
                                break;

                        case IPPROTO_UDP:
                                (void)snprintf(buf, sizeof buf,
                                        "%s udp port %s unreachable",
                                        ipaddr_string(&oip->ip_dst),
                                        udpport_string(dport));
                                break;

                        default:
                                (void)snprintf(buf, sizeof buf,
                                        "%s protocol %u port %u unreachable",
                                        ipaddr_string(&oip->ip_dst),
                                        oip->ip_p, dport);
                                break;
                        }
                        break;

                case ICMP_UNREACH_NEEDFRAG:
                        {
                        const struct mtu_discovery *mp;

                        mp = (struct mtu_discovery *)&dp->icmp_void;
                        mtu = EXTRACT_16BITS(&mp->nexthopmtu);
                        if (mtu)
                            (void)snprintf(buf, sizeof buf,
                                "%s unreachable - need to frag (mtu %u)",
                                ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
                        else
                            (void)snprintf(buf, sizeof buf,
                                "%s unreachable - need to frag",
                                ipaddr_string(&dp->icmp_ip.ip_dst));
                        }
                        break;

                default:
                        fmt = tok2str(unreach2str, "#%u %%s unreachable",
                            dp->icmp_code);
                        (void)snprintf(buf, sizeof buf, fmt,
                            ipaddr_string(&dp->icmp_ip.ip_dst));
                        break;
                }
                break;

        case ICMP_REDIRECT:
                TCHECK(dp->icmp_ip.ip_dst);
                fmt = tok2str(type2str, "redirect-#%u %%s to net %%s",
                    dp->icmp_code);
                (void)snprintf(buf, sizeof buf, fmt,
                    ipaddr_string(&dp->icmp_ip.ip_dst),
                    ipaddr_string(&dp->icmp_gwaddr));
                break;

        case ICMP_ROUTERADVERT:
                {
                const struct ih_rdiscovery *ihp;
                const struct id_rdiscovery *idp;
                u_int lifetime, num, size;

                (void)strlcpy(buf, "router advertisement", sizeof(buf));

                ihp = (struct ih_rdiscovery *)&dp->icmp_void;
                TCHECK(*ihp);
                (void)strlcat(buf, " lifetime ", sizeof(buf));
                lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
                if (lifetime < 60)
                        (void)snprintf(buf2, sizeof(buf2), "%u", lifetime);
                else if (lifetime < 60 * 60)
                        (void)snprintf(buf2, sizeof(buf2), "%u:%02u",
                            lifetime / 60, lifetime % 60);
                else
                        (void)snprintf(buf2, sizeof(buf2), "%u:%02u:%02u",
                            lifetime / 3600, (lifetime % 3600) / 60,
                            lifetime % 60);
                strlcat(buf, buf2, sizeof(buf));

                num = ihp->ird_addrnum;
                (void)snprintf(buf2, sizeof(buf2), " %u:", num);
                strlcat(buf, buf2, sizeof(buf));

                size = ihp->ird_addrsiz;
                if (size != 2) {
                        (void)snprintf(buf2, sizeof(buf2), " [size %u]", size);
                        strlcat(buf, buf2, sizeof(buf));
                        break;
                }
                idp = (struct id_rdiscovery *)&dp->icmp_data;
                while (num-- > 0) {
                        TCHECK(*idp);
                        (void)snprintf(buf2, sizeof(buf2), " {%s %u}",
                            ipaddr_string(&idp->ird_addr),
                            EXTRACT_32BITS(&idp->ird_pref));
                        strlcat(buf, buf2, sizeof(buf));
                }
                }
                break;

        case ICMP_TIMXCEED:
                TCHECK(dp->icmp_ip.ip_dst);
                switch (dp->icmp_code) {

                case ICMP_TIMXCEED_INTRANS:
                        str = "time exceeded in-transit";
                        break;

                case ICMP_TIMXCEED_REASS:
                        str = "ip reassembly time exceeded";
                        break;

                default:
                        (void)snprintf(buf, sizeof buf,
                                "time exceeded-#%u", dp->icmp_code);
                        break;
                }
                break;

        case ICMP_PARAMPROB:
                switch (dp->icmp_code) {
                case ICMP_PARAMPROB_OPTABSENT:
                        str = "requested option absent";
                        break;
                case ICMP_PARAMPROB_LENGTH:
                        snprintf(buf, sizeof buf, "bad length %u", dp->icmp_pptr);
                        break;
                default:
                        TCHECK(dp->icmp_pptr);
                        (void)snprintf(buf, sizeof buf,
                                "parameter problem - octet %u",
                                dp->icmp_pptr);
                        break;
                }
                break;

        case ICMP_MASKREPLY:
                TCHECK(dp->icmp_mask);
                (void)snprintf(buf, sizeof buf, "address mask is 0x%08x",
                    (u_int32_t)ntohl(dp->icmp_mask));
                break;

        default:
                str = tok2str(icmp2str, "type-#%u", dp->icmp_type);
                break;
        }
        printf("icmp: %s", str);
        if (vflag) {
                if (TTEST2(dp->icmp_type, length)) {
                        u_int16_t sum, icmp_sum;
                        sum = in_cksum((const u_short *)dp, length, 0);
                        if (sum != 0) {
                                icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
                                printf(" [bad icmp cksum %x! -> %x]", icmp_sum,
                                    in_cksum_shouldbe(icmp_sum, sum));
                        }
                        else
                                printf(" [icmp cksum ok]");
                }
        }
        if (vflag > 1 && !ICMP_INFOTYPE(dp->icmp_type) &&
            TTEST(dp->icmp_ip)) {
                printf(" for ");
                oip = &dp->icmp_ip;
                ip_print((u_char *)oip, ntohs(oip->ip_len));
        }
        return;
trunc:
        printf("[|icmp]");
}