ipft_tx.c revision 172776 
1/*	$FreeBSD: head/contrib/ipfilter/lib/ipft_tx.c 172776 2007-10-18 21:52:14Z darrenr $	*/
2
3/*
4 * Copyright (C) 2000-2006 by Darren Reed.
5 *
6 * See the IPFILTER.LICENCE file for details on licencing.
7 *
8 * $Id: ipft_tx.c,v 1.15.2.10 2007/09/03 21:54:44 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 1.15.2.10 2007/09/03 21:54:44 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;
79
80	if (ISDIGIT(*name))
81		return (u_short)atoi(name);
82	sp = getservbyname(name, tx_proto);
83	if (sp)
84		return ntohs(sp->s_port);
85	(void) fprintf(stderr, "unknown service \"%s\".\n", name);
86	return 0;
87}
88
89
90char	*tx_icmptypes[] = {
91	"echorep", (char *)NULL, (char *)NULL, "unreach", "squench",
92	"redir", (char *)NULL, (char *)NULL, "echo", "routerad",
93	"routersol", "timex", "paramprob", "timest", "timestrep",
94	"inforeq", "inforep", "maskreq", "maskrep", "END"
95};
96
97static	int	text_open(fname)
98char	*fname;
99{
100	if (tfp && tfd != -1) {
101		rewind(tfp);
102		return tfd;
103	}
104
105	if (!strcmp(fname, "-")) {
106		tfd = 0;
107		tfp = stdin;
108	} else {
109		tfd = open(fname, O_RDONLY);
110		if (tfd != -1)
111			tfp = fdopen(tfd, "r");
112	}
113	return tfd;
114}
115
116
117static	int	text_close()
118{
119	int	cfd = tfd;
120
121	tfd = -1;
122	return close(cfd);
123}
124
125
126static	int	text_readip(buf, cnt, ifn, dir)
127char	*buf, **ifn;
128int	cnt, *dir;
129{
130	register char *s;
131	char	line[513];
132	ip_t	*ip;
133
134	*ifn = NULL;
135	while (fgets(line, sizeof(line)-1, tfp)) {
136		if ((s = strchr(line, '\n')))
137			*s = '\0';
138		if ((s = strchr(line, '\r')))
139			*s = '\0';
140		if ((s = strchr(line, '#')))
141			*s = '\0';
142		if (!*line)
143			continue;
144		if ((opts & OPT_DEBUG) != 0)
145			printf("input: %s\n", line);
146		*ifn = NULL;
147		*dir = 0;
148		if (!parseline(line, (ip_t *)buf, ifn, dir)) {
149			ip = (ip_t *)buf;
150			return ntohs(ip->ip_len);
151		}
152	}
153	if (feof(tfp))
154		return 0;
155	return -1;
156}
157
158static	int	parseline(line, ip, ifn, out)
159char	*line;
160ip_t	*ip;
161char	**ifn;
162int	*out;
163{
164	tcphdr_t	th, *tcp = &th;
165	struct	icmp	icmp, *ic = &icmp;
166	char	*cps[20], **cpp, c, ipopts[68];
167	int	i, r;
168
169	if (*ifn)
170		free(*ifn);
171	bzero((char *)ip, MAX(sizeof(*tcp), sizeof(*ic)) + sizeof(*ip));
172	bzero((char *)tcp, sizeof(*tcp));
173	bzero((char *)ic, sizeof(*ic));
174	bzero(ipopts, sizeof(ipopts));
175	IP_HL_A(ip, sizeof(*ip) >> 2);
176	IP_V_A(ip, IPVERSION);
177	for (i = 0, cps[0] = strtok(line, " \b\t\r\n"); cps[i] && i < 19; )
178		cps[++i] = strtok(NULL, " \b\t\r\n");
179
180	cpp = cps;
181	if (!*cpp)
182		return 1;
183
184	c = **cpp;
185	if (!ISALPHA(c) || (TOLOWER(c) != 'o' && TOLOWER(c) != 'i')) {
186		fprintf(stderr, "bad direction \"%s\"\n", *cpp);
187		return 1;
188	}
189	*out = (TOLOWER(c) == 'o') ? 1 : 0;
190	cpp++;
191	if (!*cpp)
192		return 1;
193
194	if (!strcasecmp(*cpp, "on")) {
195		cpp++;
196		if (!*cpp)
197			return 1;
198		*ifn = strdup(*cpp++);
199		if (!*cpp)
200			return 1;
201	}
202
203	c = **cpp;
204	ip->ip_len = sizeof(ip_t);
205	if (!strcasecmp(*cpp, "tcp") || !strcasecmp(*cpp, "udp") ||
206	    !strcasecmp(*cpp, "icmp")) {
207		if (c == 't') {
208			ip->ip_p = IPPROTO_TCP;
209			ip->ip_len += sizeof(struct tcphdr);
210			tx_proto = "tcp";
211		} else if (c == 'u') {
212			ip->ip_p = IPPROTO_UDP;
213			ip->ip_len += sizeof(struct udphdr);
214			tx_proto = "udp";
215		} else {
216			ip->ip_p = IPPROTO_ICMP;
217			ip->ip_len += ICMPERR_IPICMPHLEN;
218			tx_proto = "icmp";
219		}
220		cpp++;
221	} else if (ISDIGIT(**cpp) && !index(*cpp, '.')) {
222		ip->ip_p = atoi(*cpp);
223		cpp++;
224	} else
225		ip->ip_p = IPPROTO_IP;
226
227	if (!*cpp)
228		return 1;
229	if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
230		char	*last;
231
232		last = strchr(*cpp, ',');
233		if (!last) {
234			fprintf(stderr, "tcp/udp with no source port\n");
235			return 1;
236		}
237		*last++ = '\0';
238		tcp->th_sport = htons(tx_portnum(last));
239		if (ip->ip_p == IPPROTO_TCP) {
240			tcp->th_win = htons(4096);
241			TCP_OFF_A(tcp, sizeof(*tcp) >> 2);
242		}
243	}
244	ip->ip_src.s_addr = tx_hostnum(*cpp, &r);
245	cpp++;
246	if (!*cpp)
247		return 1;
248
249	if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
250		char	*last;
251
252		last = strchr(*cpp, ',');
253		if (!last) {
254			fprintf(stderr, "tcp/udp with no destination port\n");
255			return 1;
256		}
257		*last++ = '\0';
258		tcp->th_dport = htons(tx_portnum(last));
259	}
260	ip->ip_dst.s_addr = tx_hostnum(*cpp, &r);
261	cpp++;
262	if (ip->ip_p == IPPROTO_TCP) {
263		if (*cpp != NULL) {
264			char	*s, *t;
265
266			tcp->th_flags = 0;
267			for (s = *cpp; *s; s++)
268				if ((t  = strchr(myflagset, *s)))
269					tcp->th_flags |= myflags[t-myflagset];
270			if (tcp->th_flags)
271				cpp++;
272		}
273
274		if (tcp->th_flags & TH_URG)
275			tcp->th_urp = htons(1);
276
277		if (*cpp && !strncasecmp(*cpp, "seq=", 4)) {
278			tcp->th_seq = htonl(atoi(*cpp + 4));
279			cpp++;
280		}
281
282		if (*cpp && !strncasecmp(*cpp, "ack=", 4)) {
283			tcp->th_ack = htonl(atoi(*cpp + 4));
284			cpp++;
285		}
286	} else if (*cpp && ip->ip_p == IPPROTO_ICMP) {
287		extern	char	*tx_icmptypes[];
288		char	**s, *t;
289		int	i;
290
291		t = strchr(*cpp, ',');
292		if (t != NULL)
293			*t = '\0';
294
295		for (s = tx_icmptypes, i = 0; !*s || strcmp(*s, "END");
296		     s++, i++) {
297			if (*s && !strcasecmp(*cpp, *s)) {
298				ic->icmp_type = i;
299				if (t != NULL)
300					ic->icmp_code = atoi(t + 1);
301				cpp++;
302				break;
303			}
304		}
305		if (t != NULL)
306			*t = ',';
307	}
308
309	if (*cpp && !strcasecmp(*cpp, "opt")) {
310		u_long	olen;
311
312		cpp++;
313		olen = buildopts(*cpp, ipopts, (IP_HL(ip) - 5) << 2);
314		if (olen) {
315			bcopy(ipopts, (char *)(ip + 1), olen);
316			IP_HL_A(ip, IP_HL(ip) + (olen >> 2));
317		}
318	}
319	if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)
320		bcopy((char *)tcp, ((char *)ip) + (IP_HL(ip) << 2),
321			sizeof(*tcp));
322	else if (ip->ip_p == IPPROTO_ICMP)
323		bcopy((char *)ic, ((char *)ip) + (IP_HL(ip) << 2),
324			sizeof(*ic));
325	ip->ip_len = htons(ip->ip_len);
326	return 0;
327}
328