m_pedit.c revision 6107d297aca301a0e2fdefce63a451131a98d66f 
1/*
2 * m_pedit.c		generic packet editor actions module
3 *
4 *		This program is free software; you can distribute it and/or
5 *		modify it under the terms of the GNU General Public License
6 *		as published by the Free Software Foundation; either version
7 *		2 of the License, or (at your option) any later version.
8 *
9 * Authors:  J Hadi Salim (hadi@cyberus.ca)
10 *
11 * TODO:
12 * 	1) Big endian broken in some spots
13 * 	2) A lot of this stuff was added on the fly; get a big double-double
14 * 	and clean it up at some point.
15 *
16 */
17
18#include <stdio.h>
19#include <stdlib.h>
20#include <unistd.h>
21#include <syslog.h>
22#include <fcntl.h>
23#include <sys/socket.h>
24#include <netinet/in.h>
25#include <arpa/inet.h>
26#include <string.h>
27#include <dlfcn.h>
28#include "utils.h"
29#include "tc_util.h"
30#include "m_pedit.h"
31
32static struct m_pedit_util *pedit_list;
33int pedit_debug = 1;
34
35static void
36p_explain(void)
37{
38	fprintf(stderr, "Usage: ... pedit <MUNGE>\n");
39	fprintf(stderr,
40		"Where: MUNGE := <RAW>|<LAYERED>\n"
41		"<RAW>:= <OFFSETC>[ATC]<CMD>\n "
42		"OFFSETC:= offset <offval> <u8|u16|u32>\n "
43		"ATC:= at <atval> offmask <maskval> shift <shiftval>\n "
44		"NOTE: offval is byte offset, must be multiple of 4\n "
45		"NOTE: maskval is a 32 bit hex number\n "
46		"NOTE: shiftval is a is a shift value\n "
47		"CMD:= clear | invert | set <setval>| retain\n "
48		"<LAYERED>:= ip <ipdata> | ip6 <ip6data> \n "
49		" | udp <udpdata> | tcp <tcpdata> | icmp <icmpdata> \n"
50		"For Example usage look at the examples directory");
51
52}
53
54#define usage() return(-1)
55
56static int
57pedit_parse_nopopt (int *argc_p, char ***argv_p,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
58{
59	int argc = *argc_p;
60	char **argv = *argv_p;
61
62	if (argc) {
63		fprintf(stderr, "Unknown action  hence option \"%s\" is unparsable\n", *argv);
64			return -1;
65	}
66
67	return 0;
68
69}
70
71struct m_pedit_util
72*get_pedit_kind(char *str)
73{
74	static void *pBODY;
75	void *dlh;
76	char buf[256];
77	struct  m_pedit_util *p;
78
79	for (p = pedit_list; p; p = p->next) {
80		if (strcmp(p->id, str) == 0)
81			return p;
82	}
83
84	snprintf(buf, sizeof(buf), "p_%s.so", str);
85	dlh = dlopen(buf, RTLD_LAZY);
86	if (dlh == NULL) {
87		dlh = pBODY;
88		if (dlh == NULL) {
89			dlh = pBODY = dlopen(NULL, RTLD_LAZY);
90			if (dlh == NULL)
91				goto noexist;
92		}
93	}
94
95	snprintf(buf, sizeof(buf), "p_pedit_%s", str);
96	p = dlsym(dlh, buf);
97	if (p == NULL)
98		goto noexist;
99
100reg:
101	p->next = pedit_list;
102	pedit_list = p;
103	return p;
104
105noexist:
106	p = malloc(sizeof(*p));
107	if (p) {
108		memset(p, 0, sizeof(*p));
109		strncpy(p->id, str, sizeof(p->id)-1);
110		p->parse_peopt = pedit_parse_nopopt;
111		goto reg;
112	}
113	return p;
114}
115
116int
117pack_key(struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
118{
119	int hwm = sel->nkeys;
120
121	if (hwm >= MAX_OFFS)
122		return -1;
123
124	if (tkey->off % 4) {
125		fprintf(stderr, "offsets MUST be in 32 bit boundaries\n");
126		return -1;
127	}
128
129	sel->keys[hwm].val = tkey->val;
130	sel->keys[hwm].mask = tkey->mask;
131	sel->keys[hwm].off = tkey->off;
132	sel->keys[hwm].at = tkey->at;
133	sel->keys[hwm].offmask = tkey->offmask;
134	sel->keys[hwm].shift = tkey->shift;
135	sel->nkeys++;
136	return 0;
137}
138
139
140int
141pack_key32(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
142{
143	if (tkey->off > (tkey->off & ~3)) {
144		fprintf(stderr,
145			"pack_key32: 32 bit offsets must begin in 32bit boundaries\n");
146		return -1;
147	}
148
149	tkey->val = htonl(tkey->val & retain);
150	tkey->mask = htonl(tkey->mask | ~retain);
151	/* jamal remove this - it is not necessary given the if check above */
152	tkey->off &= ~3;
153	return pack_key(sel,tkey);
154}
155
156int
157pack_key16(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
158{
159	int ind = 0, stride = 0;
160	__u32 m[4] = {0xFFFF0000,0xFF0000FF,0x0000FFFF};
161
162	if (0 > tkey->off) {
163		ind = tkey->off + 1;
164		if (0 > ind)
165			ind = -1*ind;
166	} else {
167		ind = tkey->off;
168	}
169
170	if (tkey->val > 0xFFFF || tkey->mask > 0xFFFF) {
171		fprintf(stderr, "pack_key16 bad value\n");
172		return -1;
173	}
174
175	ind = tkey->off & 3;
176
177	if (0 > ind || 2 < ind) {
178		fprintf(stderr, "pack_key16 bad index value %d\n",ind);
179		return -1;
180	}
181
182	stride = 8 * ind;
183	tkey->val = htons(tkey->val);
184	if (stride > 0) {
185		tkey->val <<= stride;
186		tkey->mask <<= stride;
187		retain <<= stride;
188	}
189	tkey->mask = retain|m[ind];
190
191	tkey->off &= ~3;
192
193	if (pedit_debug)
194		printf("pack_key16: Final val %08x mask %08x \n",tkey->val,tkey->mask);
195	return pack_key(sel,tkey);
196
197}
198
199int
200pack_key8(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
201{
202	int ind = 0, stride = 0;
203	__u32 m[4] = {0xFFFFFF00,0xFFFF00FF,0xFF00FFFF,0x00FFFFFF};
204
205	if (0 > tkey->off) {
206		ind = tkey->off + 1;
207		if (0 > ind)
208			ind = -1*ind;
209	} else {
210		ind = tkey->off;
211	}
212
213	if (tkey->val > 0xFF || tkey->mask > 0xFF) {
214		fprintf(stderr, "pack_key8 bad value (val %x mask %x\n", tkey->val, tkey->mask);
215		return -1;
216	}
217
218	ind = tkey->off & 3;
219	stride = 8 * ind;
220	tkey->val <<= stride;
221	tkey->mask <<= stride;
222	retain <<= stride;
223	tkey->mask = retain|m[ind];
224	tkey->off &= ~3;
225
226	if (pedit_debug)
227		printf("pack_key8: Final word off %d  val %08x mask %08x \n",tkey->off , tkey->val,tkey->mask);
228	return pack_key(sel,tkey);
229}
230
231int
232parse_val(int *argc_p, char ***argv_p, __u32 * val, int type)
233{
234	int argc = *argc_p;
235	char **argv = *argv_p;
236
237	if (argc <= 0)
238		return -1;
239
240	if (TINT == type)
241		return get_integer(val, *argv, 0);
242	if (TU32 == type)
243		return get_u32(val, *argv, 0);
244	if (TIPV4 == type) {
245		inet_prefix addr;
246		if (get_prefix_1(&addr, *argv, AF_INET)) {
247			return -1;
248		}
249		*val=addr.data[0];
250		return 0;
251	}
252	if (TIPV6 == type) {
253		/* not implemented yet */
254		return -1;
255	}
256
257	return -1;
258}
259
260int
261parse_cmd(int *argc_p, char ***argv_p, __u32 len, int type,__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
262{
263	__u32 mask = 0, val = 0;
264	__u32 o = 0xFF;
265	int res = -1;
266	int argc = *argc_p;
267	char **argv = *argv_p;
268
269	if (argc <= 0)
270		return -1;
271
272	if (pedit_debug)
273		printf("parse_cmd argc %d %s offset %d length %d\n",argc,*argv,tkey->off,len);
274
275	if (len == 2)
276		o = 0xFFFF;
277	if (len == 4)
278		o = 0xFFFFFFFF;
279
280	if (matches(*argv, "invert") == 0) {
281		retain = val = mask = o;
282	} else if (matches(*argv, "set") == 0) {
283		NEXT_ARG();
284		if (parse_val(&argc, &argv, &val, type))
285			return -1;
286	} else if (matches(*argv, "preserve") == 0) {
287		retain = mask = o;
288	} else {
289		if (matches(*argv, "clear") != 0)
290			return -1;
291	}
292
293	argc--; argv++;
294
295	if (argc && matches(*argv, "retain") == 0) {
296		NEXT_ARG();
297		if (parse_val(&argc, &argv, &retain, TU32))
298			return -1;
299		argc--; argv++;
300	}
301
302	tkey->val = val;
303
304	if (len == 1) {
305		tkey->mask = 0xFF;
306		res = pack_key8(retain,sel,tkey);
307		goto done;
308	}
309	if (len == 2) {
310		tkey->mask = mask;
311		res = pack_key16(retain,sel,tkey);
312		goto done;
313	}
314	if (len == 4) {
315		tkey->mask = mask;
316		res = pack_key32(retain,sel,tkey);
317		goto done;
318	}
319
320	return -1;
321done:
322	if (pedit_debug)
323		printf("parse_cmd done argc %d %s offset %d length %d\n",argc,*argv,tkey->off,len);
324	*argc_p = argc;
325	*argv_p = argv;
326	return res;
327
328}
329
330int
331parse_offset(int *argc_p, char ***argv_p,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
332{
333	int off;
334	__u32 len, retain;
335	int argc = *argc_p;
336	char **argv = *argv_p;
337	int res = -1;
338
339	if (argc <= 0)
340		return -1;
341
342	if (get_integer(&off, *argv, 0))
343		return -1;
344	tkey->off = off;
345
346	argc--;
347	argv++;
348
349	if (argc <= 0)
350		return -1;
351
352
353	if (matches(*argv, "u32") == 0) {
354		len = 4;
355		retain = 0xFFFFFFFF;
356		goto done;
357	}
358	if (matches(*argv, "u16") == 0) {
359		len = 2;
360		retain = 0x0;
361		goto done;
362	}
363	if (matches(*argv, "u8") == 0) {
364		len = 1;
365		retain = 0x0;
366		goto done;
367	}
368
369	return -1;
370
371done:
372
373	NEXT_ARG();
374
375	/* [at <someval> offmask <maskval> shift <shiftval>] */
376	if (matches(*argv, "at") == 0) {
377
378		__u32 atv=0,offmask=0x0,shift=0;
379
380		NEXT_ARG();
381		if (get_u32(&atv, *argv, 0))
382			return -1;
383		tkey->at = atv;
384
385		NEXT_ARG();
386
387		if (get_u32(&offmask, *argv, 16))
388			return -1;
389		tkey->offmask = offmask;
390
391		NEXT_ARG();
392
393		if (get_u32(&shift, *argv, 0))
394			return -1;
395		tkey->shift = shift;
396
397		NEXT_ARG();
398	}
399
400	res = parse_cmd(&argc, &argv, len, TU32,retain,sel,tkey);
401
402	*argc_p = argc;
403	*argv_p = argv;
404	return res;
405}
406
407int
408parse_munge(int *argc_p, char ***argv_p,struct tc_pedit_sel *sel)
409{
410	struct tc_pedit_key tkey;
411	int argc = *argc_p;
412	char **argv = *argv_p;
413	int res = -1;
414
415	if (argc <= 0)
416		return -1;
417
418	memset(&tkey, 0, sizeof(tkey));
419
420	if (matches(*argv, "offset") == 0) {
421		NEXT_ARG();
422		res = parse_offset(&argc, &argv,sel,&tkey);
423		goto done;
424#if jamal
425	} else if (strcmp(*argv, "help") == 0) {
426		p_explain();
427		return -1;
428#endif
429	} else {
430		char k[16];
431		struct m_pedit_util *p = NULL;
432
433		strncpy(k, *argv, sizeof (k) - 1);
434
435		if (argc > 0 ) {
436			p = get_pedit_kind(k);
437			if (NULL == p)
438				goto bad_val;
439			res = p->parse_peopt(&argc, &argv, sel,&tkey);
440			if (res < 0) {
441				fprintf(stderr,"bad pedit parsing\n");
442				goto bad_val;
443			}
444			goto done;
445		}
446	}
447
448bad_val:
449	return -1;
450
451done:
452
453	*argc_p = argc;
454	*argv_p = argv;
455	return res;
456}
457
458int
459parse_pedit(struct action_util *a, int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n)
460{
461	struct {
462		struct tc_pedit_sel sel;
463		struct tc_pedit_key keys[MAX_OFFS];
464	} sel;
465
466	int argc = *argc_p;
467	char **argv = *argv_p;
468	int ok = 0, iok = 0;
469	struct rtattr *tail;
470
471	memset(&sel, 0, sizeof(sel));
472
473	while (argc > 0) {
474		if (pedit_debug > 1)
475			fprintf(stderr, "while pedit (%d:%s)\n",argc, *argv);
476		if (matches(*argv, "pedit") == 0) {
477			NEXT_ARG();
478			ok++;
479			continue;
480		} else if (matches(*argv, "munge") == 0) {
481			if (!ok) {
482				fprintf(stderr, "Illegal pedit construct (%s) \n", *argv);
483				p_explain();
484				return -1;
485			}
486			NEXT_ARG();
487			if (parse_munge(&argc, &argv,&sel.sel)) {
488				fprintf(stderr, "Illegal pedit construct (%s) \n", *argv);
489				p_explain();
490				return -1;
491			}
492			ok++;
493		} else {
494			break;
495		}
496
497	}
498
499	if (!ok) {
500		p_explain();
501		return -1;
502	}
503
504	if (argc) {
505		if (matches(*argv, "reclassify") == 0) {
506			sel.sel.action = TC_ACT_RECLASSIFY;
507			NEXT_ARG();
508		} else if (matches(*argv, "pipe") == 0) {
509			sel.sel.action = TC_ACT_PIPE;
510			NEXT_ARG();
511		} else if (matches(*argv, "drop") == 0 ||
512			matches(*argv, "shot") == 0) {
513			sel.sel.action = TC_ACT_SHOT;
514			NEXT_ARG();
515		} else if (matches(*argv, "continue") == 0) {
516			sel.sel.action = TC_ACT_UNSPEC;
517			NEXT_ARG();
518		} else if (matches(*argv, "pass") == 0) {
519			sel.sel.action = TC_ACT_OK;
520			NEXT_ARG();
521		}
522	}
523
524	if (argc) {
525		if (matches(*argv, "index") == 0) {
526			NEXT_ARG();
527			if (get_u32(&sel.sel.index, *argv, 10)) {
528				fprintf(stderr, "Pedit: Illegal \"index\"\n");
529				return -1;
530			}
531			argc--;
532			argv++;
533			iok++;
534		}
535	}
536
537	tail = (struct rtattr *) (((void *) n) + NLMSG_ALIGN(n->nlmsg_len));
538	addattr_l(n, MAX_MSG, tca_id, NULL, 0);
539	addattr_l(n, MAX_MSG, TCA_PEDIT_PARMS,&sel, sizeof(sel.sel)+sel.sel.nkeys*sizeof(struct tc_pedit_key));
540	tail->rta_len =
541	    (((void *) n) + NLMSG_ALIGN(n->nlmsg_len)) - (void *) tail;
542
543	*argc_p = argc;
544	*argv_p = argv;
545	return 0;
546}
547
548int
549print_pedit(struct action_util *au,FILE * f, struct rtattr *arg)
550{
551	struct tc_pedit_sel *sel;
552	struct rtattr *tb[TCA_PEDIT_MAX + 1];
553	SPRINT_BUF(b1);
554
555	if (arg == NULL)
556		return -1;
557
558	memset(tb, 0, sizeof (tb));
559	parse_rtattr(tb, TCA_PEDIT_MAX, RTA_DATA(arg), RTA_PAYLOAD(arg));
560
561	if (tb[TCA_PEDIT_PARMS] == NULL) {
562		fprintf(f, "[NULL pedit parameters]");
563		return -1;
564	}
565	sel = RTA_DATA(tb[TCA_PEDIT_PARMS]);
566
567	fprintf(f, " pedit action %s keys %d\n ", action_n2a(sel->action, b1, sizeof (b1)),sel->nkeys);
568	fprintf(f, "\t index %d ref %d bind %d", sel->index,sel->refcnt, sel->bindcnt);
569
570	if (show_stats) {
571		if (tb[TCA_PEDIT_TM]) {
572			struct tcf_t *tm = RTA_DATA(tb[TCA_PEDIT_TM]);
573			print_tm(f,tm);
574		}
575	}
576	if (sel->nkeys) {
577		int i;
578		struct tc_pedit_key *key = sel->keys;
579
580		for (i=0; i<sel->nkeys; i++, key++) {
581			fprintf(f, "\n\t key #%d",i);
582			fprintf(f, "  at %d: val %08x mask %08x",
583			(unsigned int)key->off,
584			(unsigned int)ntohl(key->val),
585			(unsigned int)ntohl(key->mask));
586		}
587	} else {
588		fprintf(f, "\npedit %x keys %d is not LEGIT", sel->index,sel->nkeys);
589	}
590
591
592	fprintf(f, "\n ");
593	return 0;
594}
595
596int
597pedit_print_xstats(struct action_util *au, FILE *f, struct rtattr *xstats)
598{
599	return 0;
600}
601
602struct action_util pedit_action_util = {
603	.id = "pedit",
604	.parse_aopt = parse_pedit,
605	.print_aopt = print_pedit,
606};
607