ipft_tx.c revision 153881 
1/*	$FreeBSD: head/contrib/ipfilter/lib/ipft_tx.c 153881 2005-12-30 11:52:26Z guido $	*/
2
3/*
4 * Copyright (C) 1995-2001 by Darren Reed.
5 *
6 * See the IPFILTER.LICENCE file for details on licencing.
7 *
8 * $Id: ipft_tx.c,v 1.15.2.6 2005/12/04 10:07:22 darrenr Exp $
9 */
10#if !defined(lint)
11static const char sccsid[] = "@(#)ipft_tx.c	1.7 6/5/96 (C) 1993 Darren Reed";
12static const char rcsid[] = "@(#)$Id: ipft_tx.c,v 1.15.2.6 2005/12/04 10:07:22 darrenr Exp $";
13#endif
14
15#include <ctype.h>
16
17#include "ipf.h"
18#include "ipt.h"
19
20#ifndef linux
21#include <netinet/ip_var.h>
22#endif
23#include <netinet/tcpip.h>
24
25
26extern	int	opts;
27
28static	char	*tx_proto = "";
29
30static	int	text_open __P((char *)), text_close __P((void));
31static	int	text_readip __P((char *, int, char **, int *));
32static	int	parseline __P((char *, ip_t *, char **, int *));
33
34static	char	myflagset[] = "FSRPAUEC";
35static	u_char	myflags[] = { TH_FIN, TH_SYN, TH_RST, TH_PUSH,
36				TH_ACK, TH_URG, TH_ECN, TH_CWR };
37
38struct	ipread	iptext = { text_open, text_close, text_readip, R_DO_CKSUM };
39static	FILE	*tfp = NULL;
40static	int	tfd = -1;
41
42static	u_32_t	tx_hostnum __P((char *, int *));
43static	u_short	tx_portnum __P((char *));
44
45
46/*
47 * returns an ip address as a long var as a result of either a DNS lookup or
48 * straight inet_addr() call
49 */
50static	u_32_t	tx_hostnum(host, resolved)
51char	*host;
52int	*resolved;
53{
54	u_32_t	ipa;
55
56	*resolved = 0;
57	if (!strcasecmp("any", host))
58		return 0L;
59	if (ISDIGIT(*host))
60		return inet_addr(host);
61
62	if (gethost(host, &ipa) == -1) {
63		*resolved = -1;
64		fprintf(stderr, "can't resolve hostname: %s\n", host);
65		return 0;
66	}
67	return ipa;
68}
69
70
71/*
72 * find the port number given by the name, either from getservbyname() or
73 * straight atoi()
74 */
75static	u_short	tx_portnum(name)
76char	*name;
77{
78	struct	servent	*sp, *sp2;
79	u_short	p1 = 0;
80
81	if (ISDIGIT(*name))
82		return (u_short)atoi(name);
83	if (!tx_proto)
84		tx_proto = "tcp/udp";
85	if (strcasecmp(tx_proto, "tcp/udp")) {
86		sp = getservbyname(name, tx_proto);
87		if (sp)
88			return ntohs(sp->s_port);
89		(void) fprintf(stderr, "unknown service \"%s\".\n", name);
90		return 0;
91	}
92	sp = getservbyname(name, "tcp");
93	if (sp)
94		p1 = sp->s_port;
95	sp2 = getservbyname(name, "udp");
96	if (!sp || !sp2) {
97		(void) fprintf(stderr, "unknown tcp/udp service \"%s\".\n",
98			name);
99		return 0;
100	}
101	if (p1 != sp2->s_port) {
102		(void) fprintf(stderr, "%s %d/tcp is a different port to ",
103			name, p1);
104		(void) fprintf(stderr, "%s %d/udp\n", name, sp->s_port);
105		return 0;
106	}
107	return ntohs(p1);
108}
109
110
111char	*tx_icmptypes[] = {
112	"echorep", (char *)NULL, (char *)NULL, "unreach", "squench",
113	"redir", (char *)NULL, (char *)NULL, "echo", "routerad",
114	"routersol", "timex", "paramprob", "timest", "timestrep",
115	"inforeq", "inforep", "maskreq", "maskrep", "END"
116};
117
118static	int	text_open(fname)
119char	*fname;
120{
121	if (tfp && tfd != -1) {
122		rewind(tfp);
123		return tfd;
124	}
125
126	if (!strcmp(fname, "-")) {
127		tfd = 0;
128		tfp = stdin;
129	} else {
130		tfd = open(fname, O_RDONLY);
131		if (tfd != -1)
132			tfp = fdopen(tfd, "r");
133	}
134	return tfd;
135}
136
137
138static	int	text_close()
139{
140	int	cfd = tfd;
141
142	tfd = -1;
143	return close(cfd);
144}
145
146
147static	int	text_readip(buf, cnt, ifn, dir)
148char	*buf, **ifn;
149int	cnt, *dir;
150{
151	register char *s;
152	char	line[513];
153
154	*ifn = NULL;
155	while (fgets(line, sizeof(line)-1, tfp)) {
156		if ((s = strchr(line, '\n')))
157			*s = '\0';
158		if ((s = strchr(line, '\r')))
159			*s = '\0';
160		if ((s = strchr(line, '#')))
161			*s = '\0';
162		if (!*line)
163			continue;
164		if ((opts & OPT_DEBUG) != 0)
165			printf("input: %s\n", line);
166		*ifn = NULL;
167		*dir = 0;
168		if (!parseline(line, (ip_t *)buf, ifn, dir))
169#if 0
170			return sizeof(ip_t) + sizeof(tcphdr_t);
171#else
172			return sizeof(ip_t);
173#endif
174	}
175	if (feof(tfp))
176		return 0;
177	return -1;
178}
179
180static	int	parseline(line, ip, ifn, out)
181char	*line;
182ip_t	*ip;
183char	**ifn;
184int	*out;
185{
186	tcphdr_t	th, *tcp = &th;
187	struct	icmp	icmp, *ic = &icmp;
188	char	*cps[20], **cpp, c, ipopts[68];
189	int	i, r;
190
191	if (*ifn)
192		free(*ifn);
193	bzero((char *)ip, MAX(sizeof(*tcp), sizeof(*ic)) + sizeof(*ip));
194	bzero((char *)tcp, sizeof(*tcp));
195	bzero((char *)ic, sizeof(*ic));
196	bzero(ipopts, sizeof(ipopts));
197	IP_HL_A(ip, sizeof(*ip) >> 2);
198	IP_V_A(ip, IPVERSION);
199	for (i = 0, cps[0] = strtok(line, " \b\t\r\n"); cps[i] && i < 19; )
200		cps[++i] = strtok(NULL, " \b\t\r\n");
201
202	cpp = cps;
203	if (!*cpp)
204		return 1;
205
206	c = **cpp;
207	if (!ISALPHA(c) || (TOLOWER(c) != 'o' && TOLOWER(c) != 'i')) {
208		fprintf(stderr, "bad direction \"%s\"\n", *cpp);
209		return 1;
210	}
211	*out = (TOLOWER(c) == 'o') ? 1 : 0;
212	cpp++;
213	if (!*cpp)
214		return 1;
215
216	if (!strcasecmp(*cpp, "on")) {
217		cpp++;
218		if (!*cpp)
219			return 1;
220		*ifn = strdup(*cpp++);
221		if (!*cpp)
222			return 1;
223	}
224
225	c = **cpp;
226	ip->ip_len = sizeof(ip_t);
227	if (!strcasecmp(*cpp, "tcp") || !strcasecmp(*cpp, "udp") ||
228	    !strcasecmp(*cpp, "icmp")) {
229		if (c == 't') {
230			ip->ip_p = IPPROTO_TCP;
231			ip->ip_len += sizeof(struct tcphdr);
232			tx_proto = "tcp";
233		} else if (c == 'u') {
234			ip->ip_p = IPPROTO_UDP;
235			ip->ip_len += sizeof(struct udphdr);
236			tx_proto = "udp";
237		} else {
238			ip->ip_p = IPPROTO_ICMP;
239			ip->ip_len += ICMPERR_IPICMPHLEN;
240			tx_proto = "icmp";
241		}
242		cpp++;
243	} else if (ISDIGIT(**cpp) && !index(*cpp, '.')) {
244		ip->ip_p = atoi(*cpp);
245		cpp++;
246	} else
247		ip->ip_p = IPPROTO_IP;
248
249	if (!*cpp)
250		return 1;
251	if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
252		char	*last;
253
254		last = strchr(*cpp, ',');
255		if (!last) {
256			fprintf(stderr, "tcp/udp with no source port\n");
257			return 1;
258		}
259		*last++ = '\0';
260		tcp->th_sport = htons(tx_portnum(last));
261		if (ip->ip_p == IPPROTO_TCP) {
262			tcp->th_win = htons(4096);
263			TCP_OFF_A(tcp, sizeof(*tcp) >> 2);
264		}
265	}
266	ip->ip_src.s_addr = tx_hostnum(*cpp, &r);
267	cpp++;
268	if (!*cpp)
269		return 1;
270
271	if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
272		char	*last;
273
274		last = strchr(*cpp, ',');
275		if (!last) {
276			fprintf(stderr, "tcp/udp with no destination port\n");
277			return 1;
278		}
279		*last++ = '\0';
280		tcp->th_dport = htons(tx_portnum(last));
281	}
282	ip->ip_dst.s_addr = tx_hostnum(*cpp, &r);
283	cpp++;
284	if (*cpp && ip->ip_p == IPPROTO_TCP) {
285		char	*s, *t;
286
287		tcp->th_flags = 0;
288		for (s = *cpp; *s; s++)
289			if ((t  = strchr(myflagset, *s)))
290				tcp->th_flags |= myflags[t - myflagset];
291		if (tcp->th_flags)
292			cpp++;
293		if (tcp->th_flags == 0)
294			abort();
295		if (tcp->th_flags & TH_URG)
296			tcp->th_urp = htons(1);
297	} else if (*cpp && ip->ip_p == IPPROTO_ICMP) {
298		extern	char	*tx_icmptypes[];
299		char	**s, *t;
300		int	i;
301
302		t = strchr(*cpp, ',');
303		if (t != NULL)
304			*t = '\0';
305
306		for (s = tx_icmptypes, i = 0; !*s || strcmp(*s, "END");
307		     s++, i++) {
308			if (*s && !strcasecmp(*cpp, *s)) {
309				ic->icmp_type = i;
310				if (t != NULL)
311					ic->icmp_code = atoi(t + 1);
312				cpp++;
313				break;
314			}
315		}
316		if (t != NULL)
317			*t = ',';
318	}
319
320	if (*cpp && !strcasecmp(*cpp, "opt")) {
321		u_long	olen;
322
323		cpp++;
324		olen = buildopts(*cpp, ipopts, (IP_HL(ip) - 5) << 2);
325		if (olen) {
326			bcopy(ipopts, (char *)(ip + 1), olen);
327			IP_HL_A(ip, IP_HL(ip) + (olen >> 2));
328		}
329	}
330	if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)
331		bcopy((char *)tcp, ((char *)ip) + (IP_HL(ip) << 2),
332			sizeof(*tcp));
333	else if (ip->ip_p == IPPROTO_ICMP)
334		bcopy((char *)ic, ((char *)ip) + (IP_HL(ip) << 2),
335			sizeof(*ic));
336	ip->ip_len = htons(ip->ip_len);
337	return 0;
338}
339