lib/common/ipft_tx.c

	ipft_tx.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * Copyright (C) 1995-2001 by Darren Reed.
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * $Id: ipft_tx.c,v 1.11 2003/02/16 02:32:01 darrenr Exp $
 */
#if !defined(lint)
static const char sccsid[] = "@(#)ipft_tx.c 1.7 6/5/96 (C) 1993 Darren Reed";
static const char rcsid[] = "@(#)$Id: ipft_tx.c,v 1.11 2003/02/16 02:32:01 darrenr Exp $";
#endif

#include <ctype.h>

#include "ipf.h"
#include "ipt.h"

#undef  ICMP_MAXTYPE
#include <netinet/ip_icmp.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/tcpip.h>


extern  int opts;

static  char    *tx_proto = "";

static  int text_open __P((char *)), text_close __P((void));
static  int text_readip __P((char *, int, char **, int *));
static  int parseline __P((char *, ip_t *, char **, int *));

static  char    _tcp_flagset[] = "FSRPAUEC";
static  u_char  _tcp_flags[] = { TH_FIN, TH_SYN, TH_RST, TH_PUSH,
                TH_ACK, TH_URG, TH_ECN, TH_CWR };

struct  ipread  iptext = { text_open, text_close, text_readip, R_DO_CKSUM };
static  FILE    *tfp = NULL;
static  int tfd = -1;

static  u_32_t  tx_hostnum __P((char *, int *));
static  u_short tx_portnum __P((char *));


/*
 * returns an ip address as a long var as a result of either a DNS lookup or
 * straight inet_addr() call
 */
static  u_32_t  tx_hostnum(host, resolved)
char    *host;
int *resolved;
{
    struct  hostent *hp;
    struct  netent  *np;

    *resolved = 0;
    if (!strcasecmp("any",host))
        return 0L;
    if (isdigit(*host))
        return inet_addr(host);

    if (!(hp = gethostbyname(host))) {
        if (!(np = getnetbyname(host))) {
            *resolved = -1;
            fprintf(stderr, "can't resolve hostname: %s\n", host);
            return 0;
        }
        return htonl(np->n_net);
    }
    return *(u_32_t *)hp->h_addr;
}


/*
 * find the port number given by the name, either from getservbyname() or
 * straight atoi()
 */
static  u_short tx_portnum(name)
char    *name;
{
    struct  servent *sp, *sp2;
    u_short p1 = 0;

    if (isdigit(*name))
        return (u_short)atoi(name);
    if (!tx_proto)
        tx_proto = "tcp/udp";
    if (strcasecmp(tx_proto, "tcp/udp")) {
        sp = getservbyname(name, tx_proto);
        if (sp)
            return ntohs(sp->s_port);
        (void) fprintf(stderr, "unknown service \"%s\".\n", name);
        return 0;
    }
    sp = getservbyname(name, "tcp");
    if (sp)
        p1 = sp->s_port;
    sp2 = getservbyname(name, "udp");
    if (!sp || !sp2) {
        (void) fprintf(stderr, "unknown tcp/udp service \"%s\".\n",
            name);
        return 0;
    }
    if (p1 != sp2->s_port) {
        (void) fprintf(stderr, "%s %d/tcp is a different port to ",
            name, p1);
        (void) fprintf(stderr, "%s %d/udp\n", name, sp->s_port);
        return 0;
    }
    return ntohs(p1);
}


char    *tx_icmptypes[] = {
    "echorep", (char *)NULL, (char *)NULL, "unreach", "squench",
    "redir", (char *)NULL, (char *)NULL, "echo", "routerad",
    "routersol", "timex", "paramprob", "timest", "timestrep",
    "inforeq", "inforep", "maskreq", "maskrep", "END"
};

static  int text_open(fname)
char    *fname;
{
    if (tfp && tfd != -1) {
        rewind(tfp);
        return tfd;
    }

    if (!strcmp(fname, "-")) {
        tfd = 0;
        tfp = stdin;
    } else {
        tfd = open(fname, O_RDONLY);
        if (tfd != -1)
            tfp = fdopen(tfd, "r");
    }
    return tfd;
}


static  int text_close()
{
    int cfd = tfd;

    tfd = -1;
    return close(cfd);
}


static  int text_readip(buf, cnt, ifn, dir)
char    *buf, **ifn;
int cnt, *dir;
{
    register char *s;
    char    line[513];

    *ifn = NULL;
    while (fgets(line, sizeof(line)-1, tfp)) {
        if ((s = strchr(line, '\n')))
            *s = '\0';
        if ((s = strchr(line, '\r')))
            *s = '\0';
        if ((s = strchr(line, '#')))
            *s = '\0';
        if (!*line)
            continue;
        if (!(opts & OPT_BRIEF))
            printf("input: %s\n", line);
        *ifn = NULL;
        *dir = 0;
        if (!parseline(line, (ip_t *)buf, ifn, dir))
#if 0
            return sizeof(ip_t) + sizeof(tcphdr_t);
#else
            return sizeof(ip_t);
#endif
    }
    return -1;
}

static  int parseline(line, ip, ifn, out)
char    *line;
ip_t    *ip;
char    **ifn;
int *out;
{
    tcphdr_t    th, *tcp = &th;
    struct  icmp    icmp, *ic = &icmp;
    char    *cps[20], **cpp, c, ipopts[68];
    int i, r;

    if (*ifn)
        free(*ifn);
    bzero((char *)ip, MAX(sizeof(*tcp), sizeof(*ic)) + sizeof(*ip));
    bzero((char *)tcp, sizeof(*tcp));
    bzero((char *)ic, sizeof(*ic));
    bzero(ipopts, sizeof(ipopts));
    IP_HL_A(ip, sizeof(*ip) >> 2);
    IP_V_A(ip, IPVERSION);
    for (i = 0, cps[0] = strtok(line, " \b\t\r\n"); cps[i] && i < 19; )
        cps[++i] = strtok(NULL, " \b\t\r\n");

    cpp = cps;
    if (!*cpp)
        return 1;

    c = **cpp;
    if (!isalpha(c) || (tolower(c) != 'o' && tolower(c) != 'i')) {
        fprintf(stderr, "bad direction \"%s\"\n", *cpp);
        return 1;
    }
    *out = (tolower(c) == 'o') ? 1 : 0;
    cpp++;
    if (!*cpp)
        return 1;

    if (!strcasecmp(*cpp, "on")) {
        cpp++;
        if (!*cpp)
            return 1;
        *ifn = strdup(*cpp++);
        if (!*cpp)
            return 1;
    }

    c = **cpp;
    ip->ip_len = sizeof(ip_t);
    if (!strcasecmp(*cpp, "tcp") || !strcasecmp(*cpp, "udp") ||
        !strcasecmp(*cpp, "icmp")) {
        if (c == 't') {
            ip->ip_p = IPPROTO_TCP;
            ip->ip_len += sizeof(struct tcphdr);
            tx_proto = "tcp";
        } else if (c == 'u') {
            ip->ip_p = IPPROTO_UDP;
            ip->ip_len += sizeof(struct udphdr);
            tx_proto = "udp";
        } else {
            ip->ip_p = IPPROTO_ICMP;
            ip->ip_len += ICMPERR_IPICMPHLEN;
            tx_proto = "icmp";
        }
        cpp++;
    } else if (isdigit(**cpp) && !index(*cpp, '.')) {
        ip->ip_p = atoi(*cpp);
        cpp++;
    } else
        ip->ip_p = IPPROTO_IP;

    if (!*cpp)
        return 1;
    if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
        char    *last;

        last = strchr(*cpp, ',');
        if (!last) {
            fprintf(stderr, "tcp/udp with no source port\n");
            return 1;
        }
        *last++ = '\0';
        tcp->th_sport = htons(tx_portnum(last));
    }
    ip->ip_src.s_addr = tx_hostnum(*cpp, &r);
    cpp++;
    if (!*cpp)
        return 1;

    if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
        char    *last;

        last = strchr(*cpp, ',');
        if (!last) {
            fprintf(stderr, "tcp/udp with no destination port\n");
            return 1;
        }
        *last++ = '\0';
        tcp->th_dport = htons(tx_portnum(last));
    }
    ip->ip_dst.s_addr = tx_hostnum(*cpp, &r);
    cpp++;
    if (*cpp && ip->ip_p == IPPROTO_TCP) {
        extern  char    _tcp_flagset[];
        extern  u_char  _tcp_flags[];
        char    *s, *t;

        for (s = *cpp; *s; s++)
            if ((t  = strchr(_tcp_flagset, *s)))
                tcp->th_flags |= _tcp_flags[t - _tcp_flagset];
        if (tcp->th_flags)
            cpp++;
        if (tcp->th_flags == 0)
            abort();
        tcp->th_win = htons(4096);
        TCP_OFF_A(tcp, sizeof(*tcp) >> 2);
    } else if (*cpp && ip->ip_p == IPPROTO_ICMP) {
        extern  char    *tx_icmptypes[];
        char    **s, *t;
        int i;

        for (s = tx_icmptypes, i = 0; !*s || strcmp(*s, "END");
             s++, i++)
            if (*s && !strncasecmp(*cpp, *s, strlen(*s))) {
                ic->icmp_type = i;
                if ((t = strchr(*cpp, ',')))
                    ic->icmp_code = atoi(t+1);
                cpp++;
                break;
            }
    }

    if (*cpp && !strcasecmp(*cpp, "opt")) {
        u_long  olen;

        cpp++;
        olen = buildopts(*cpp, ipopts, (IP_HL(ip) - 5) << 2);
        if (olen) {
            bcopy(ipopts, (char *)(ip + 1), olen);
            IP_HL_A(ip, IP_HL(ip) + (olen >> 2));
        }
    }
    if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)
        bcopy((char *)tcp, ((char *)ip) + (IP_HL(ip) << 2),
            sizeof(*tcp));
    else if (ip->ip_p == IPPROTO_ICMP)
        bcopy((char *)ic, ((char *)ip) + (IP_HL(ip) << 2),
            sizeof(*ic));
    ip->ip_len = htons(ip->ip_len);
    return 0;
}