/*      $OpenBSD: tcpdump.c,v 1.100 2025/05/16 05:47:30 kn Exp $        */

/*
 * Copyright (c) 1988, 1989, 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.
 */

/*
 * tcpdump - monitor tcp/ip traffic on an ethernet.
 *
 * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory.
 * Mercilessly hacked and occasionally improved since then via the
 * combined efforts of Van, Steve McCanne and Craig Leres of LBL.
 */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <sys/wait.h>

#include <netinet/in.h>

#include <pcap.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>

#include "interface.h"
#include "addrtoname.h"
#include "setsignal.h"
#include "gmt2local.h"

#include <sys/socket.h>
#include <net/if.h>
#include <net/pfvar.h>
#include "extract.h"
#include "pfctl.h"
#include "pfctl_parser.h"
#include "privsep.h"

int Aflag;                      /* dump ascii */
int aflag;                      /* translate network and broadcast addresses */
int Bflag = BPF_FILDROP_PASS;   /* BPF fildrop setting */
int dflag;                      /* print filter code */
int eflag;                      /* print ethernet header */
int fflag;                      /* don't translate "foreign" IP address */
int Iflag;                      /* include interface in output */
int Lflag;                      /* List available link types */
int nflag;                      /* leave addresses as numbers */
int Nflag;                      /* remove domains from printed host names */
int Oflag = 1;                  /* run filter code optimizer */
int oflag;                      /* print passive OS fingerprints */
int pflag;                      /* don't go promiscuous */
int qflag;                      /* quick (shorter) output */
int Sflag;                      /* print raw TCP sequence numbers */
int tflag = 1;                  /* print packet arrival time */
int vflag;                      /* verbose */
int xflag;                      /* print packet in hex */
int Xflag;                      /* print packet in emacs-hexl style */

int packettype;

char *program_name;
char *device = NULL;

int32_t thiszone;               /* seconds offset from gmt to local time */

extern volatile pid_t child_pid;

/* Externs */
extern void bpf_dump(struct bpf_program *, int);
extern int esp_init(char *);

/* Forwards */
void    cleanup(int);
void    gotchld(int);
extern __dead void usage(void);

/* Length of saved portion of packet. */
int snaplen = 0;

struct printer {
        pcap_handler f;
        int type;
};

/* XXX needed if using old bpf.h */
#ifndef DLT_ATM_RFC1483
#define DLT_ATM_RFC1483 11
#endif

static struct printer printers[] = {
        { ether_if_print,               DLT_EN10MB },
        { ether_if_print,               DLT_IEEE802 },
        { sl_if_print,                  DLT_SLIP },
        { sl_bsdos_if_print,            DLT_SLIP_BSDOS },
        { ppp_if_print,                 DLT_PPP },
        { ppp_hdlc_if_print,            DLT_PPP_SERIAL },
        { fddi_if_print,                DLT_FDDI },
        { null_if_print,                DLT_NULL },
        { raw_if_print,                 DLT_RAW },
        { atm_if_print,                 DLT_ATM_RFC1483 },
        { loop_if_print,                DLT_LOOP },
        { enc_if_print,                 DLT_ENC },
        { pflog_if_print,               DLT_PFLOG },
        { pfsync_if_print,              DLT_PFSYNC },
        { ppp_ether_if_print,           DLT_PPP_ETHER },
        { ieee802_11_if_print,          DLT_IEEE802_11 },
        { ieee802_11_radio_if_print,    DLT_IEEE802_11_RADIO },
        { ofp_if_print,                 DLT_OPENFLOW },
        { usbpcap_if_print,             DLT_USBPCAP },
        { NULL,                         0 },
};

static pcap_handler
lookup_printer(int type)
{
        struct printer *p;

        for (p = printers; p->f; ++p) {
                if (type == p->type)
                        return p->f;
        }

        error("unknown data link type 0x%x", type);
        /* NOTREACHED */
}

static int
init_pfosfp(void)
{
        pf_osfp_initialize();
        if (pfctl_file_fingerprints(-1,
            PF_OPT_QUIET|PF_OPT_NOACTION, PF_OSFP_FILE) == 0)
                return 1;
        return 0;
}

static pcap_t *pd;

/* Multiple DLT support */
void             pcap_list_linktypes(pcap_t *);
void             pcap_print_linktype(u_int);

void
pcap_print_linktype(u_int dlt)
{
        const char *name;

        if ((name = pcap_datalink_val_to_name(dlt)) != NULL)
                fprintf(stderr, "%s\n", name);
        else
                fprintf(stderr, "<unknown: %u>\n", dlt);
}

void
pcap_list_linktypes(pcap_t *p)
{
        int fd = p->fd;
        u_int n;

#define MAXDLT  100

        u_int dltlist[MAXDLT];
        struct bpf_dltlist dl = {MAXDLT, dltlist};

        if (fd < 0)
                error("Invalid bpf descriptor");

        if (ioctl(fd, BIOCGDLTLIST, &dl) == -1)
                err(1, "BIOCGDLTLIST");

        if (dl.bfl_len > MAXDLT)
                error("Invalid number of linktypes: %u", dl.bfl_len);

        fprintf(stderr, "%d link type%s supported:\n", dl.bfl_len,
            dl.bfl_len == 1 ? "" : "s");

        for (n = 0; n < dl.bfl_len; n++) {
                fprintf(stderr, "\t");
                pcap_print_linktype(dltlist[n]);
        }
}

int
main(int argc, char **argv)
{
        int cnt = -1, op, i;
        bpf_u_int32 localnet, netmask;
        char *cp, *RFileName = NULL;
        char ebuf[PCAP_ERRBUF_SIZE], *WFileName = NULL;
        pcap_handler printer;
        struct bpf_program *fcode;
        u_char *pcap_userdata;
        u_int dirfilt = 0, dlt = (u_int) -1;
        const char *errstr;

        if ((cp = strrchr(argv[0], '/')) != NULL)
                program_name = cp + 1;
        else
                program_name = argv[0];

        /* '-P' used internally, exec privileged portion */
        if (argc >= 2 && strcmp("-P", argv[1]) == 0)
                priv_exec(argc, argv);

        if (priv_init(argc, argv))
                error("Failed to setup privsep");

        /* state: STATE_INIT */

        opterr = 0;
        while ((op = getopt(argc, argv,
            "AaB:c:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:")) != -1)
                switch (op) {

                case 'A':
                        xflag = 1;
                        Aflag = 1;
                        break;

                case 'a':
                        aflag = 1;
                        break;

                case 'B':
                        if (strcasecmp(optarg, "pass") == 0)
                                Bflag = BPF_FILDROP_PASS;
                        else if (strcasecmp(optarg, "capture") == 0)
                                Bflag = BPF_FILDROP_CAPTURE;
                        else if (strcasecmp(optarg, "drop") == 0)
                                Bflag = BPF_FILDROP_DROP;
                        else {
                                error("invalid BPF fildrop option: %s",
                                    optarg);
                        }
                        break;

                case 'c':
                        cnt = strtonum(optarg, 1, INT_MAX, &errstr);
                        if (errstr)
                                error("invalid packet count %s: %s",
                                    optarg, errstr);
                        break;

                case 'D':
                        if (strcasecmp(optarg, "in") == 0)
                                dirfilt = BPF_DIRECTION_OUT;
                        else if (strcasecmp(optarg, "out") == 0)
                                dirfilt = BPF_DIRECTION_IN;
                        else
                                error("invalid traffic direction %s", optarg);
                        break;

                case 'd':
                        ++dflag;
                        break;
                case 'e':
                        eflag = 1;
                        break;

                case 'f':
                        fflag = 1;
                        break;

                case 'F':
                        break;

                case 'i':
                        device = optarg;
                        break;

                case 'I':
                        Iflag = 1;
                        break;

                case 'l':
                        setvbuf(stdout, NULL, _IOLBF, 0);
                        break;
                case 'L':
                        Lflag = 1;
                        break;
                case 'n':
                        nflag = 1;
                        break;

                case 'N':
                        Nflag = 1;
                        break;

                case 'O':
                        Oflag = 0;
                        break;

                case 'o':
                        oflag = 1;
                        break;

                case 'p':
                        pflag = 1;
                        break;

                case 'q':
                        qflag = 1;
                        break;

                case 'r':
                        RFileName = optarg;
                        break;

                case 's':
                        snaplen = strtonum(optarg, 1, INT_MAX, &errstr);
                        if (errstr)
                                error("invalid snaplen %s: %s", optarg, errstr);
                        break;

                case 'S':
                        Sflag = 1;
                        break;

                case 't':
                        --tflag;
                        break;

                case 'T':
                        if (strcasecmp(optarg, "vat") == 0)
                                packettype = PT_VAT;
                        else if (strcasecmp(optarg, "wb") == 0)
                                packettype = PT_WB;
                        else if (strcasecmp(optarg, "rpc") == 0)
                                packettype = PT_RPC;
                        else if (strcasecmp(optarg, "rtp") == 0)
                                packettype = PT_RTP;
                        else if (strcasecmp(optarg, "rtcp") == 0)
                                packettype = PT_RTCP;
                        else if (strcasecmp(optarg, "cnfp") == 0)
                                packettype = PT_CNFP;
                        else if (strcasecmp(optarg, "vrrp") == 0)
                                packettype = PT_VRRP;
                        else if (strcasecmp(optarg, "tcp") == 0)
                                packettype = PT_TCP;
                        else if (strcasecmp(optarg, "gre") == 0)
                                packettype = PT_GRE;
                        else if (strcasecmp(optarg, "vxlan") == 0)
                                packettype = PT_VXLAN;
                        else if (strcasecmp(optarg, "geneve") == 0)
                                packettype = PT_GENEVE;
                        else if (strcasecmp(optarg, "erspan") == 0)
                                packettype = PT_ERSPAN;
                        else if (strcasecmp(optarg, "mpls") == 0)
                                packettype = PT_MPLS;
                        else if (strcasecmp(optarg, "tftp") == 0)
                                packettype = PT_TFTP;
                        else if (strcasecmp(optarg, "wg") == 0)
                                packettype = PT_WIREGUARD;
                        else if (strcasecmp(optarg, "sack") == 0)
                                /*
                                 * kept for compatibility; DEFAULT_SNAPLEN
                                 * used to be too short to capture SACK.
                                 */
                                ;
                        else
                                error("unknown packet type `%s'", optarg);
                        break;

                case 'v':
                        ++vflag;
                        break;

                case 'w':
                        WFileName = optarg;
                        break;

                case 'y':
                        i = pcap_datalink_name_to_val(optarg);
                        if (i < 0)
                                error("invalid data link type: %s", optarg);
                        dlt = (u_int)i;
                        break;

                case 'x':
                        xflag = 1;
                        break;

                case 'X':
                        Xflag = 1;
                        xflag = 1;
                        break;

                case 'E':
                        if (esp_init(optarg) < 0)
                                error("bad esp specification `%s'", optarg);
                        break;

                default:
                        usage();
                        /* NOTREACHED */
                }

        if (snaplen == 0) {
                switch (dlt) {
                case DLT_IEEE802_11:
                        snaplen = IEEE802_11_SNAPLEN;
                        break;
                case DLT_IEEE802_11_RADIO:
                        snaplen = IEEE802_11_RADIO_SNAPLEN;
                        break;
                default:
                        snaplen = DEFAULT_SNAPLEN;
                        break;
                }
        }

        if (aflag && nflag)
                error("-a and -n options are incompatible");

        if (RFileName != NULL) {
                pd = priv_pcap_offline(RFileName, ebuf);
                if (pd == NULL)
                        error("%s", ebuf);
                /* state: STATE_BPF */
                localnet = 0;
                netmask = 0;
                if (fflag != 0)
                        error("-f and -r options are incompatible");
        } else {
                if (device == NULL) {
                        device = pcap_lookupdev(ebuf);
                        if (device == NULL)
                                error("%s", ebuf);
                }
                pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf,
                    dlt, dirfilt, Bflag);
                if (pd == NULL)
                        error("%s", ebuf);

                /* state: STATE_BPF */
                if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) {
                        if (fflag)
                                warning("%s", ebuf);
                        localnet = 0;
                        netmask = 0;
                }
        }
        i = pcap_snapshot(pd);
        if (snaplen < i) {
                warning("snaplen raised from %d to %d", snaplen, i);
                snaplen = i;
        }

        if (Lflag) {
                pcap_list_linktypes(pd);
                exit(0);
        }

        fcode = priv_pcap_setfilter(pd, Oflag, netmask);
        /* state: STATE_FILTER */
        if (fcode == NULL)
                error("%s", pcap_geterr(pd));
        if (dflag) {
                bpf_dump(fcode, dflag);
                exit(0);
        }
        if (oflag)
                oflag = init_pfosfp();
        init_addrtoname(localnet, netmask);

        if (WFileName) {
                pcap_dumper_t *p;

                p = priv_pcap_dump_open(pd, WFileName);
                /* state: STATE_RUN */
                if (p == NULL)
                        error("%s", pcap_geterr(pd));
                {
                        FILE *fp = (FILE *)p;   /* XXX touching pcap guts! */
                        fflush(fp);
                        setvbuf(fp, NULL, _IONBF, 0);
                }
                printer = pcap_dump;
                pcap_userdata = (u_char *)p;
        } else {
                printer = lookup_printer(pcap_datalink(pd));
                pcap_userdata = NULL;
                priv_init_done();
                /* state: STATE_RUN */
        }
        if (RFileName == NULL) {
                (void)fprintf(stderr, "%s: listening on %s, link-type ",
                    program_name, device);
                pcap_print_linktype(pd->linktype);
                (void)fflush(stderr);
        }

        if (tflag > 0)
                thiszone = gmt2local(0);

        if (pledge("stdio", NULL) == -1)
                err(1, "pledge");

        if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) {
                (void)fprintf(stderr, "%s: pcap_loop: %s\n",
                    program_name, pcap_geterr(pd));
                exit(1);
        }
        pcap_close(pd);
        exit(0);
}

/* make a clean exit on interrupts */
void
cleanup(int signo)
{
        struct pcap_stat stat;
        sigset_t allsigs;

        sigfillset(&allsigs);
        sigprocmask(SIG_BLOCK, &allsigs, NULL);

        /* Can't print the summary if reading from a savefile */
        dprintf(STDERR_FILENO, "\n");
        if (pd != NULL && pcap_file(pd) == NULL) {
                if (priv_pcap_stats(&stat) < 0) {
                        dprintf(STDERR_FILENO,
                            "pcap_stats: %s\n", pcap_geterr(pd));
                } else {
                        dprintf(STDERR_FILENO,
                            "%u packets received by filter\n", stat.ps_recv);
                        dprintf(STDERR_FILENO,
                            "%u packets dropped by kernel\n", stat.ps_drop);
                }
        }
        _exit(0);
}

void
gotchld(int signo)
{
        pid_t pid;
        int status;
        int save_err = errno;

        do {
                pid = waitpid(child_pid, &status, WNOHANG);
                if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status)))
                        cleanup(0);
        } while (pid == -1 && errno == EINTR);

        if (pid == -1)
                _exit(1);

        errno = save_err;
}

/* dump the buffer in `emacs-hexl' style */
void
default_print_hexl(const u_char *cp, unsigned int length)
{
        unsigned int i, j, jm;
        int c;
        char ln[128], buf[128];

        printf("\n");
        for (i = 0; i < length; i += 0x10) {
                snprintf(ln, sizeof(ln), "  %04x: ", (unsigned int)i);
                jm = length - i;
                jm = jm > 16 ? 16 : jm;

                for (j = 0; j < jm; j++) {
                        if ((j % 2) == 1)
                                snprintf(buf, sizeof(buf), "%02x ",
                                    (unsigned int)cp[i+j]);
                        else
                                snprintf(buf, sizeof(buf), "%02x",
                                    (unsigned int)cp[i+j]);
                        strlcat(ln, buf, sizeof ln);
                }
                for (; j < 16; j++) {
                        if ((j % 2) == 1)
                                snprintf(buf, sizeof buf, "   ");
                        else
                                snprintf(buf, sizeof buf, "  ");
                        strlcat(ln, buf, sizeof ln);
                }

                strlcat(ln, " ", sizeof ln);
                for (j = 0; j < jm; j++) {
                        c = cp[i+j];
                        c = isprint(c) ? c : '.';
                        buf[0] = c;
                        buf[1] = '\0';
                        strlcat(ln, buf, sizeof ln);
                }
                printf("%s\n", ln);
        }
}

/* dump the text from the buffer */
void
default_print_ascii(const u_char *cp, unsigned int length)
{
        int c, i;

        printf("\n");
        for (i = 0; i < length; i++) {
                c = cp[i];
                if (isprint(c) || c == '\t' || c == '\n' || c == '\r')
                        putchar(c);
                else
                        putchar('.');
        }
}

void
default_print(const u_char *bp, u_int length)
{
        u_int i;
        int nshorts;

        if (snapend - bp < length)
                length = snapend - bp;

        if (Xflag) {
                /* dump the buffer in `emacs-hexl' style */
                default_print_hexl(bp, length);
        } else if (Aflag) {
                /* dump the text in the buffer */
                default_print_ascii(bp, length);
        } else {
                u_short sp;

                /* dump the buffer in old tcpdump style */
                nshorts = (u_int) length / sizeof(u_short);
                i = 0;
                while (--nshorts >= 0) {
                        if ((i++ % 8) == 0)
                                printf("\n\t\t\t");

                        sp = EXTRACT_16BITS(bp);
                        bp += sizeof(sp);
                        printf(" %04x", sp);
                }
                if (length & 1) {
                        if ((i % 8) == 0)
                                printf("\n\t\t\t");
                        printf(" %02x", *bp);
                }
        }
}

void
set_slave_signals(void)
{
        setsignal(SIGTERM, cleanup);
        setsignal(SIGINT, cleanup);
        setsignal(SIGCHLD, gotchld);
        setsignal(SIGHUP, cleanup);
}

__dead void
usage(void)
{
        (void)fprintf(stderr,
"Usage: %s [-AadefILlNnOopqStvXx] [-B fildrop] [-c count] [-D direction]\n",
            program_name);
        (void)fprintf(stderr,
"\t       [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n");
        (void)fprintf(stderr,
"\t       [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression ...]\n");
        exit(1);
}