blob: 3fc5348d9092de701072bbedf15f6e47243ac83f [file] [log] [blame] [raw]
/*
* Copyright (C) 1995-2001 by Darren Reed.
*
* See the IPFILTER.LICENCE file for details on licencing.
*
* $Id$
*/
#if !defined(lint)
static const char sccsid[] = "@(#)ipft_tx.c 1.7 6/5/96 (C) 1993 Darren Reed";
static const char rcsid[] = "@(#)$Id$";
#endif
#include <ctype.h>
#include "ipf.h"
#include "ipt.h"
#ifndef linux
#include <netinet/ip_var.h>
#endif
#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 myflagset[] = "FSRPAUEC";
static u_char myflags[] = { 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;
{
u_32_t ipa;
*resolved = 0;
if (!strcasecmp("any", host))
return 0L;
if (ISDIGIT(*host))
return inet_addr(host);
if (gethost(host, &ipa) == -1) {
*resolved = -1;
fprintf(stderr, "can't resolve hostname: %s\n", host);
return 0;
}
return ipa;
}
/*
* 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;
if (ISDIGIT(*name))
return (u_short)atoi(name);
sp = getservbyname(name, tx_proto);
if (sp)
return ntohs(sp->s_port);
(void) fprintf(stderr, "unknown service \"%s\".\n", name);
return 0;
}
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];
ip_t *ip;
*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_DEBUG) != 0)
printf("input: %s\n", line);
*ifn = NULL;
*dir = 0;
if (!parseline(line, (ip_t *)buf, ifn, dir)) {
ip = (ip_t *)buf;
return ntohs(ip->ip_len);
}
}
if (feof(tfp))
return 0;
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));
if (ip->ip_p == IPPROTO_TCP) {
tcp->th_win = htons(4096);
TCP_OFF_A(tcp, sizeof(*tcp) >> 2);
}
}
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) {
char *s, *t;
tcp->th_flags = 0;
for (s = *cpp; *s; s++)
if ((t = strchr(myflagset, *s)))
tcp->th_flags |= myflags[t - myflagset];
if (tcp->th_flags)
cpp++;
if (tcp->th_flags == 0)
abort();
if (tcp->th_flags & TH_URG)
tcp->th_urp = htons(1);
} else if (*cpp && ip->ip_p == IPPROTO_ICMP) {
extern char *tx_icmptypes[];
char **s, *t;
int i;
t = strchr(*cpp, ',');
if (t != NULL)
*t = '\0';
for (s = tx_icmptypes, i = 0; !*s || strcmp(*s, "END");
s++, i++) {
if (*s && !strcasecmp(*cpp, *s)) {
ic->icmp_type = i;
if (t != NULL)
ic->icmp_code = atoi(t + 1);
cpp++;
break;
}
}
if (t != NULL)
*t = ',';
}
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;
}