m_pedit.c revision ebf32083e0a15b416357087362738e123cd0df9f 
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
36explain(void)
37{
38	fprintf(stderr, "Usage: ... pedit munge <MUNGE>\n");
39	fprintf(stderr,
40		"Where: MUNGE := <RAW>|<LAYERED>\n"
41		"\t<RAW>:= <OFFSETC>[ATC]<CMD>\n "
42		"\t\tOFFSETC:= offset <offval> <u8|u16|u32>\n "
43		"\t\tATC:= at <atval> offmask <maskval> shift <shiftval>\n "
44		"\t\tNOTE: offval is byte offset, must be multiple of 4\n "
45		"\t\tNOTE: maskval is a 32 bit hex number\n "
46		"\t\tNOTE: shiftval is a is a shift value\n "
47		"\t\tCMD:= clear | invert | set <setval>| retain\n "
48		"\t<LAYERED>:= ip <ipdata> | ip6 <ip6data> \n "
49		" \t\t| udp <udpdata> | tcp <tcpdata> | icmp <icmpdata> \n"
50		"For Example usage look at the examples directory\n");
51
52}
53
54static void
55usage(void)
56{
57	explain();
58	exit(-1);
59}
60
61static int
62pedit_parse_nopopt (int *argc_p, char ***argv_p,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
63{
64	int argc = *argc_p;
65	char **argv = *argv_p;
66
67	if (argc) {
68		fprintf(stderr, "Unknown action  hence option \"%s\" is unparsable\n", *argv);
69			return -1;
70	}
71
72	return 0;
73
74}
75
76struct m_pedit_util
77*get_pedit_kind(char *str)
78{
79	static void *pBODY;
80	void *dlh;
81	char buf[256];
82	struct  m_pedit_util *p;
83
84	for (p = pedit_list; p; p = p->next) {
85		if (strcmp(p->id, str) == 0)
86			return p;
87	}
88
89	snprintf(buf, sizeof(buf), "p_%s.so", str);
90	dlh = dlopen(buf, RTLD_LAZY);
91	if (dlh == NULL) {
92		dlh = pBODY;
93		if (dlh == NULL) {
94			dlh = pBODY = dlopen(NULL, RTLD_LAZY);
95			if (dlh == NULL)
96				goto noexist;
97		}
98	}
99
100	snprintf(buf, sizeof(buf), "p_pedit_%s", str);
101	p = dlsym(dlh, buf);
102	if (p == NULL)
103		goto noexist;
104
105reg:
106	p->next = pedit_list;
107	pedit_list = p;
108	return p;
109
110noexist:
111	p = malloc(sizeof(*p));
112	if (p) {
113		memset(p, 0, sizeof(*p));
114		strncpy(p->id, str, sizeof(p->id)-1);
115		p->parse_peopt = pedit_parse_nopopt;
116		goto reg;
117	}
118	return p;
119}
120
121int
122pack_key(struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
123{
124	int hwm = sel->nkeys;
125
126	if (hwm >= MAX_OFFS)
127		return -1;
128
129	if (tkey->off % 4) {
130		fprintf(stderr, "offsets MUST be in 32 bit boundaries\n");
131		return -1;
132	}
133
134	sel->keys[hwm].val = tkey->val;
135	sel->keys[hwm].mask = tkey->mask;
136	sel->keys[hwm].off = tkey->off;
137	sel->keys[hwm].at = tkey->at;
138	sel->keys[hwm].offmask = tkey->offmask;
139	sel->keys[hwm].shift = tkey->shift;
140	sel->nkeys++;
141	return 0;
142}
143
144
145int
146pack_key32(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
147{
148	if (tkey->off > (tkey->off & ~3)) {
149		fprintf(stderr,
150			"pack_key32: 32 bit offsets must begin in 32bit boundaries\n");
151		return -1;
152	}
153
154	tkey->val = htonl(tkey->val & retain);
155	tkey->mask = htonl(tkey->mask | ~retain);
156	/* jamal remove this - it is not necessary given the if check above */
157	tkey->off &= ~3;
158	return pack_key(sel,tkey);
159}
160
161int
162pack_key16(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
163{
164	int ind = 0, stride = 0;
165	__u32 m[4] = {0xFFFF0000,0xFF0000FF,0x0000FFFF};
166
167	if (0 > tkey->off) {
168		ind = tkey->off + 1;
169		if (0 > ind)
170			ind = -1*ind;
171	} else {
172		ind = tkey->off;
173	}
174
175	if (tkey->val > 0xFFFF || tkey->mask > 0xFFFF) {
176		fprintf(stderr, "pack_key16 bad value\n");
177		return -1;
178	}
179
180	ind = tkey->off & 3;
181
182	if (0 > ind || 2 < ind) {
183		fprintf(stderr, "pack_key16 bad index value %d\n",ind);
184		return -1;
185	}
186
187	stride = 8 * ind;
188	tkey->val = htons(tkey->val);
189	if (stride > 0) {
190		tkey->val <<= stride;
191		tkey->mask <<= stride;
192		retain <<= stride;
193	}
194	tkey->mask = retain|m[ind];
195
196	tkey->off &= ~3;
197
198	if (pedit_debug)
199		printf("pack_key16: Final val %08x mask %08x \n",tkey->val,tkey->mask);
200	return pack_key(sel,tkey);
201
202}
203
204int
205pack_key8(__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
206{
207	int ind = 0, stride = 0;
208	__u32 m[4] = {0xFFFFFF00,0xFFFF00FF,0xFF00FFFF,0x00FFFFFF};
209
210	if (0 > tkey->off) {
211		ind = tkey->off + 1;
212		if (0 > ind)
213			ind = -1*ind;
214	} else {
215		ind = tkey->off;
216	}
217
218	if (tkey->val > 0xFF || tkey->mask > 0xFF) {
219		fprintf(stderr, "pack_key8 bad value (val %x mask %x\n", tkey->val, tkey->mask);
220		return -1;
221	}
222
223	ind = tkey->off & 3;
224	stride = 8 * ind;
225	tkey->val <<= stride;
226	tkey->mask <<= stride;
227	retain <<= stride;
228	tkey->mask = retain|m[ind];
229	tkey->off &= ~3;
230
231	if (pedit_debug)
232		printf("pack_key8: Final word off %d  val %08x mask %08x \n",tkey->off , tkey->val,tkey->mask);
233	return pack_key(sel,tkey);
234}
235
236int
237parse_val(int *argc_p, char ***argv_p, __u32 * val, int type)
238{
239	int argc = *argc_p;
240	char **argv = *argv_p;
241
242	if (argc <= 0)
243		return -1;
244
245	if (TINT == type)
246		return get_integer((int *) val, *argv, 0);
247
248	if (TU32 == type)
249		return get_u32(val, *argv, 0);
250
251	if (TIPV4 == type) {
252		inet_prefix addr;
253		if (get_prefix_1(&addr, *argv, AF_INET)) {
254			return -1;
255		}
256		*val=addr.data[0];
257		return 0;
258	}
259	if (TIPV6 == type) {
260		/* not implemented yet */
261		return -1;
262	}
263
264	return -1;
265}
266
267int
268parse_cmd(int *argc_p, char ***argv_p, __u32 len, int type,__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
269{
270	__u32 mask = 0, val = 0;
271	__u32 o = 0xFF;
272	int res = -1;
273	int argc = *argc_p;
274	char **argv = *argv_p;
275
276	if (argc <= 0)
277		return -1;
278
279	if (pedit_debug)
280		printf("parse_cmd argc %d %s offset %d length %d\n",argc,*argv,tkey->off,len);
281
282	if (len == 2)
283		o = 0xFFFF;
284	if (len == 4)
285		o = 0xFFFFFFFF;
286
287	if (matches(*argv, "invert") == 0) {
288		retain = val = mask = o;
289	} else if (matches(*argv, "set") == 0) {
290		NEXT_ARG();
291		if (parse_val(&argc, &argv, &val, type))
292			return -1;
293	} else if (matches(*argv, "preserve") == 0) {
294		retain = mask = o;
295	} else {
296		if (matches(*argv, "clear") != 0)
297			return -1;
298	}
299
300	argc--; argv++;
301
302	if (argc && matches(*argv, "retain") == 0) {
303		NEXT_ARG();
304		if (parse_val(&argc, &argv, &retain, TU32))
305			return -1;
306		argc--; argv++;
307	}
308
309	tkey->val = val;
310
311	if (len == 1) {
312		tkey->mask = 0xFF;
313		res = pack_key8(retain,sel,tkey);
314		goto done;
315	}
316	if (len == 2) {
317		tkey->mask = mask;
318		res = pack_key16(retain,sel,tkey);
319		goto done;
320	}
321	if (len == 4) {
322		tkey->mask = mask;
323		res = pack_key32(retain,sel,tkey);
324		goto done;
325	}
326
327	return -1;
328done:
329	if (pedit_debug)
330		printf("parse_cmd done argc %d %s offset %d length %d\n",argc,*argv,tkey->off,len);
331	*argc_p = argc;
332	*argv_p = argv;
333	return res;
334
335}
336
337int
338parse_offset(int *argc_p, char ***argv_p,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
339{
340	int off;
341	__u32 len, retain;
342	int argc = *argc_p;
343	char **argv = *argv_p;
344	int res = -1;
345
346	if (argc <= 0)
347		return -1;
348
349	if (get_integer(&off, *argv, 0))
350		return -1;
351	tkey->off = off;
352
353	argc--;
354	argv++;
355
356	if (argc <= 0)
357		return -1;
358
359
360	if (matches(*argv, "u32") == 0) {
361		len = 4;
362		retain = 0xFFFFFFFF;
363		goto done;
364	}
365	if (matches(*argv, "u16") == 0) {
366		len = 2;
367		retain = 0x0;
368		goto done;
369	}
370	if (matches(*argv, "u8") == 0) {
371		len = 1;
372		retain = 0x0;
373		goto done;
374	}
375
376	return -1;
377
378done:
379
380	NEXT_ARG();
381
382	/* [at <someval> offmask <maskval> shift <shiftval>] */
383	if (matches(*argv, "at") == 0) {
384
385		__u32 atv=0,offmask=0x0,shift=0;
386
387		NEXT_ARG();
388		if (get_u32(&atv, *argv, 0))
389			return -1;
390		tkey->at = atv;
391
392		NEXT_ARG();
393
394		if (get_u32(&offmask, *argv, 16))
395			return -1;
396		tkey->offmask = offmask;
397
398		NEXT_ARG();
399
400		if (get_u32(&shift, *argv, 0))
401			return -1;
402		tkey->shift = shift;
403
404		NEXT_ARG();
405	}
406
407	res = parse_cmd(&argc, &argv, len, TU32,retain,sel,tkey);
408
409	*argc_p = argc;
410	*argv_p = argv;
411	return res;
412}
413
414int
415parse_munge(int *argc_p, char ***argv_p,struct tc_pedit_sel *sel)
416{
417	struct tc_pedit_key tkey;
418	int argc = *argc_p;
419	char **argv = *argv_p;
420	int res = -1;
421
422	if (argc <= 0)
423		return -1;
424
425	memset(&tkey, 0, sizeof(tkey));
426
427	if (matches(*argv, "offset") == 0) {
428		NEXT_ARG();
429		res = parse_offset(&argc, &argv,sel,&tkey);
430		goto done;
431	} else {
432		char k[16];
433		struct m_pedit_util *p = NULL;
434
435		strncpy(k, *argv, sizeof (k) - 1);
436
437		if (argc > 0 ) {
438			p = get_pedit_kind(k);
439			if (NULL == p)
440				goto bad_val;
441			res = p->parse_peopt(&argc, &argv, sel,&tkey);
442			if (res < 0) {
443				fprintf(stderr,"bad pedit parsing\n");
444				goto bad_val;
445			}
446			goto done;
447		}
448	}
449
450bad_val:
451	return -1;
452
453done:
454
455	*argc_p = argc;
456	*argv_p = argv;
457	return res;
458}
459
460int
461parse_pedit(struct action_util *a, int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n)
462{
463	struct {
464		struct tc_pedit_sel sel;
465		struct tc_pedit_key keys[MAX_OFFS];
466	} sel;
467
468	int argc = *argc_p;
469	char **argv = *argv_p;
470	int ok = 0, iok = 0;
471	struct rtattr *tail;
472
473	memset(&sel, 0, sizeof(sel));
474
475	while (argc > 0) {
476		if (pedit_debug > 1)
477			fprintf(stderr, "while pedit (%d:%s)\n",argc, *argv);
478		if (matches(*argv, "pedit") == 0) {
479			NEXT_ARG();
480			ok++;
481			continue;
482		} else if (matches(*argv, "help") == 0) {
483			usage();
484		} else if (matches(*argv, "munge") == 0) {
485			if (!ok) {
486				fprintf(stderr, "Illegal pedit construct (%s) \n", *argv);
487				explain();
488				return -1;
489			}
490			NEXT_ARG();
491			if (parse_munge(&argc, &argv,&sel.sel)) {
492				fprintf(stderr, "Illegal pedit construct (%s) \n", *argv);
493				explain();
494				return -1;
495			}
496			ok++;
497		} else {
498			break;
499		}
500
501	}
502
503	if (!ok) {
504		explain();
505		return -1;
506	}
507
508	if (argc) {
509		if (matches(*argv, "reclassify") == 0) {
510			sel.sel.action = TC_ACT_RECLASSIFY;
511			NEXT_ARG();
512		} else if (matches(*argv, "pipe") == 0) {
513			sel.sel.action = TC_ACT_PIPE;
514			NEXT_ARG();
515		} else if (matches(*argv, "drop") == 0 ||
516			matches(*argv, "shot") == 0) {
517			sel.sel.action = TC_ACT_SHOT;
518			NEXT_ARG();
519		} else if (matches(*argv, "continue") == 0) {
520			sel.sel.action = TC_ACT_UNSPEC;
521			NEXT_ARG();
522		} else if (matches(*argv, "pass") == 0) {
523			sel.sel.action = TC_ACT_OK;
524			NEXT_ARG();
525		}
526	}
527
528	if (argc) {
529		if (matches(*argv, "index") == 0) {
530			NEXT_ARG();
531			if (get_u32(&sel.sel.index, *argv, 10)) {
532				fprintf(stderr, "Pedit: Illegal \"index\"\n");
533				return -1;
534			}
535			argc--;
536			argv++;
537			iok++;
538		}
539	}
540
541	tail = NLMSG_TAIL(n);
542	addattr_l(n, MAX_MSG, tca_id, NULL, 0);
543	addattr_l(n, MAX_MSG, TCA_PEDIT_PARMS,&sel, sizeof(sel.sel)+sel.sel.nkeys*sizeof(struct tc_pedit_key));
544	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
545
546	*argc_p = argc;
547	*argv_p = argv;
548	return 0;
549}
550
551int
552print_pedit(struct action_util *au,FILE * f, struct rtattr *arg)
553{
554	struct tc_pedit_sel *sel;
555	struct rtattr *tb[TCA_PEDIT_MAX + 1];
556	SPRINT_BUF(b1);
557
558	if (arg == NULL)
559		return -1;
560
561	parse_rtattr_nested(tb, TCA_PEDIT_MAX, arg);
562
563	if (tb[TCA_PEDIT_PARMS] == NULL) {
564		fprintf(f, "[NULL pedit parameters]");
565		return -1;
566	}
567	sel = RTA_DATA(tb[TCA_PEDIT_PARMS]);
568
569	fprintf(f, " pedit action %s keys %d\n ", action_n2a(sel->action, b1, sizeof (b1)),sel->nkeys);
570	fprintf(f, "\t index %d ref %d bind %d", sel->index,sel->refcnt, sel->bindcnt);
571
572	if (show_stats) {
573		if (tb[TCA_PEDIT_TM]) {
574			struct tcf_t *tm = RTA_DATA(tb[TCA_PEDIT_TM]);
575			print_tm(f,tm);
576		}
577	}
578	if (sel->nkeys) {
579		int i;
580		struct tc_pedit_key *key = sel->keys;
581
582		for (i=0; i<sel->nkeys; i++, key++) {
583			fprintf(f, "\n\t key #%d",i);
584			fprintf(f, "  at %d: val %08x mask %08x",
585			(unsigned int)key->off,
586			(unsigned int)ntohl(key->val),
587			(unsigned int)ntohl(key->mask));
588		}
589	} else {
590		fprintf(f, "\npedit %x keys %d is not LEGIT", sel->index,sel->nkeys);
591	}
592
593
594	fprintf(f, "\n ");
595	return 0;
596}
597
598int
599pedit_print_xstats(struct action_util *au, FILE *f, struct rtattr *xstats)
600{
601	return 0;
602}
603
604struct action_util pedit_action_util = {
605	.id = "pedit",
606	.parse_aopt = parse_pedit,
607	.print_aopt = print_pedit,
608};
609