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((int *) val, *argv, 0);
242
243	if (TU32 == type)
244		return get_u32(val, *argv, 0);
245
246	if (TIPV4 == type) {
247		inet_prefix addr;
248		if (get_prefix_1(&addr, *argv, AF_INET)) {
249			return -1;
250		}
251		*val=addr.data[0];
252		return 0;
253	}
254	if (TIPV6 == type) {
255		/* not implemented yet */
256		return -1;
257	}
258
259	return -1;
260}
261
262int
263parse_cmd(int *argc_p, char ***argv_p, __u32 len, int type,__u32 retain,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
264{
265	__u32 mask = 0, val = 0;
266	__u32 o = 0xFF;
267	int res = -1;
268	int argc = *argc_p;
269	char **argv = *argv_p;
270
271	if (argc <= 0)
272		return -1;
273
274	if (pedit_debug)
275		printf("parse_cmd argc %d %s offset %d length %d\n",argc,*argv,tkey->off,len);
276
277	if (len == 2)
278		o = 0xFFFF;
279	if (len == 4)
280		o = 0xFFFFFFFF;
281
282	if (matches(*argv, "invert") == 0) {
283		retain = val = mask = o;
284	} else if (matches(*argv, "set") == 0) {
285		NEXT_ARG();
286		if (parse_val(&argc, &argv, &val, type))
287			return -1;
288	} else if (matches(*argv, "preserve") == 0) {
289		retain = mask = o;
290	} else {
291		if (matches(*argv, "clear") != 0)
292			return -1;
293	}
294
295	argc--; argv++;
296
297	if (argc && matches(*argv, "retain") == 0) {
298		NEXT_ARG();
299		if (parse_val(&argc, &argv, &retain, TU32))
300			return -1;
301		argc--; argv++;
302	}
303
304	tkey->val = val;
305
306	if (len == 1) {
307		tkey->mask = 0xFF;
308		res = pack_key8(retain,sel,tkey);
309		goto done;
310	}
311	if (len == 2) {
312		tkey->mask = mask;
313		res = pack_key16(retain,sel,tkey);
314		goto done;
315	}
316	if (len == 4) {
317		tkey->mask = mask;
318		res = pack_key32(retain,sel,tkey);
319		goto done;
320	}
321
322	return -1;
323done:
324	if (pedit_debug)
325		printf("parse_cmd done argc %d %s offset %d length %d\n",argc,*argv,tkey->off,len);
326	*argc_p = argc;
327	*argv_p = argv;
328	return res;
329
330}
331
332int
333parse_offset(int *argc_p, char ***argv_p,struct tc_pedit_sel *sel,struct tc_pedit_key *tkey)
334{
335	int off;
336	__u32 len, retain;
337	int argc = *argc_p;
338	char **argv = *argv_p;
339	int res = -1;
340
341	if (argc <= 0)
342		return -1;
343
344	if (get_integer(&off, *argv, 0))
345		return -1;
346	tkey->off = off;
347
348	argc--;
349	argv++;
350
351	if (argc <= 0)
352		return -1;
353
354
355	if (matches(*argv, "u32") == 0) {
356		len = 4;
357		retain = 0xFFFFFFFF;
358		goto done;
359	}
360	if (matches(*argv, "u16") == 0) {
361		len = 2;
362		retain = 0x0;
363		goto done;
364	}
365	if (matches(*argv, "u8") == 0) {
366		len = 1;
367		retain = 0x0;
368		goto done;
369	}
370
371	return -1;
372
373done:
374
375	NEXT_ARG();
376
377	/* [at <someval> offmask <maskval> shift <shiftval>] */
378	if (matches(*argv, "at") == 0) {
379
380		__u32 atv=0,offmask=0x0,shift=0;
381
382		NEXT_ARG();
383		if (get_u32(&atv, *argv, 0))
384			return -1;
385		tkey->at = atv;
386
387		NEXT_ARG();
388
389		if (get_u32(&offmask, *argv, 16))
390			return -1;
391		tkey->offmask = offmask;
392
393		NEXT_ARG();
394
395		if (get_u32(&shift, *argv, 0))
396			return -1;
397		tkey->shift = shift;
398
399		NEXT_ARG();
400	}
401
402	res = parse_cmd(&argc, &argv, len, TU32,retain,sel,tkey);
403
404	*argc_p = argc;
405	*argv_p = argv;
406	return res;
407}
408
409int
410parse_munge(int *argc_p, char ***argv_p,struct tc_pedit_sel *sel)
411{
412	struct tc_pedit_key tkey;
413	int argc = *argc_p;
414	char **argv = *argv_p;
415	int res = -1;
416
417	if (argc <= 0)
418		return -1;
419
420	memset(&tkey, 0, sizeof(tkey));
421
422	if (matches(*argv, "offset") == 0) {
423		NEXT_ARG();
424		res = parse_offset(&argc, &argv,sel,&tkey);
425		goto done;
426#if jamal
427	} else if (strcmp(*argv, "help") == 0) {
428		p_explain();
429		return -1;
430#endif
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, "munge") == 0) {
483			if (!ok) {
484				fprintf(stderr, "Illegal pedit construct (%s) \n", *argv);
485				p_explain();
486				return -1;
487			}
488			NEXT_ARG();
489			if (parse_munge(&argc, &argv,&sel.sel)) {
490				fprintf(stderr, "Illegal pedit construct (%s) \n", *argv);
491				p_explain();
492				return -1;
493			}
494			ok++;
495		} else {
496			break;
497		}
498
499	}
500
501	if (!ok) {
502		p_explain();
503		return -1;
504	}
505
506	if (argc) {
507		if (matches(*argv, "reclassify") == 0) {
508			sel.sel.action = TC_ACT_RECLASSIFY;
509			NEXT_ARG();
510		} else if (matches(*argv, "pipe") == 0) {
511			sel.sel.action = TC_ACT_PIPE;
512			NEXT_ARG();
513		} else if (matches(*argv, "drop") == 0 ||
514			matches(*argv, "shot") == 0) {
515			sel.sel.action = TC_ACT_SHOT;
516			NEXT_ARG();
517		} else if (matches(*argv, "continue") == 0) {
518			sel.sel.action = TC_ACT_UNSPEC;
519			NEXT_ARG();
520		} else if (matches(*argv, "pass") == 0) {
521			sel.sel.action = TC_ACT_OK;
522			NEXT_ARG();
523		}
524	}
525
526	if (argc) {
527		if (matches(*argv, "index") == 0) {
528			NEXT_ARG();
529			if (get_u32(&sel.sel.index, *argv, 10)) {
530				fprintf(stderr, "Pedit: Illegal \"index\"\n");
531				return -1;
532			}
533			argc--;
534			argv++;
535			iok++;
536		}
537	}
538
539	tail = NLMSG_TAIL(n);
540	addattr_l(n, MAX_MSG, tca_id, NULL, 0);
541	addattr_l(n, MAX_MSG, TCA_PEDIT_PARMS,&sel, sizeof(sel.sel)+sel.sel.nkeys*sizeof(struct tc_pedit_key));
542	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
543
544	*argc_p = argc;
545	*argv_p = argv;
546	return 0;
547}
548
549int
550print_pedit(struct action_util *au,FILE * f, struct rtattr *arg)
551{
552	struct tc_pedit_sel *sel;
553	struct rtattr *tb[TCA_PEDIT_MAX + 1];
554	SPRINT_BUF(b1);
555
556	if (arg == NULL)
557		return -1;
558
559	parse_rtattr_nested(tb, TCA_PEDIT_MAX, 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