Home | History | Annotate | Line # | Download | only in npfctl
npf_data.c revision 1.26 
      1 /*	$NetBSD: npf_data.c,v 1.26 2016/12/26 23:05:05 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2009-2014 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 /*
     30  * npfctl(8) data manipulation and helper routines.
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 __RCSID("$NetBSD: npf_data.c,v 1.26 2016/12/26 23:05:05 christos Exp $");
     35 
     36 #include <sys/types.h>
     37 #include <sys/null.h>
     38 #include <netinet/in.h>
     39 #include <netinet/in_systm.h>
     40 #include <netinet/ip.h>
     41 #define ICMP_STRINGS
     42 #include <netinet/ip_icmp.h>
     43 #define ICMP6_STRINGS
     44 #include <netinet/icmp6.h>
     45 #define	__FAVOR_BSD
     46 #include <netinet/tcp.h>
     47 #include <net/if.h>
     48 
     49 #include <stdlib.h>
     50 #include <stddef.h>
     51 #include <string.h>
     52 #include <ctype.h>
     53 #include <err.h>
     54 #include <errno.h>
     55 #include <ifaddrs.h>
     56 #include <netdb.h>
     57 
     58 #include "npfctl.h"
     59 
     60 static struct ifaddrs *		ifs_list = NULL;
     61 
     62 void
     63 npfctl_note_interface(const char *ifname)
     64 {
     65 	unsigned long if_idx = if_nametoindex(ifname);
     66 	bool testif = npfctl_debug_addif(ifname);
     67 	const char *p = ifname;
     68 
     69 	/* If such interface exists or if it is a test interface - done. */
     70 	if (if_idx || testif) {
     71 		return;
     72 	}
     73 
     74 	/*
     75 	 * Minimum sanity check.  The interface name shall be non-empty
     76 	 * string shorter than IFNAMSIZ and alphanumeric only.
     77 	 */
     78 	if (*p == '\0') {
     79 		goto invalid;
     80 	}
     81 	while (*p) {
     82 		const size_t len = (ptrdiff_t)p - (ptrdiff_t)ifname;
     83 
     84 		if (!isalnum((unsigned char)*p) || len > IFNAMSIZ) {
     85 invalid:		yyerror("illegitimate interface name '%s'", ifname);
     86 		}
     87 		p++;
     88 	}
     89 
     90 	/* Throw a warning, so that the user could double check. */
     91 	warnx("warning - unknown interface '%s'", ifname);
     92 }
     93 
     94 static unsigned long
     95 npfctl_find_ifindex(const char *ifname)
     96 {
     97 	unsigned long if_idx = if_nametoindex(ifname);
     98 	bool testif = npfctl_debug_addif(ifname);
     99 
    100 	if (!if_idx) {
    101 		if (testif) {
    102 			static u_int dummy_if_idx = (1 << 15);
    103 			return ++dummy_if_idx;
    104 		}
    105 		yyerror("unknown interface '%s'", ifname);
    106 	}
    107 	return if_idx;
    108 }
    109 
    110 static bool
    111 npfctl_copy_address(sa_family_t fam, npf_addr_t *addr, const void *ptr)
    112 {
    113 	memset(addr, 0, sizeof(npf_addr_t));
    114 
    115 	switch (fam) {
    116 	case AF_INET: {
    117 		const struct sockaddr_in *sin = ptr;
    118 		memcpy(addr, &sin->sin_addr, sizeof(sin->sin_addr));
    119 		return true;
    120 	}
    121 	case AF_INET6: {
    122 		const struct sockaddr_in6 *sin6 = ptr;
    123 		memcpy(addr, &sin6->sin6_addr, sizeof(sin6->sin6_addr));
    124 		return true;
    125 	}
    126 	default:
    127 		yyerror("unknown address family %u", fam);
    128 		return false;
    129 	}
    130 }
    131 
    132 static bool
    133 npfctl_parse_fam_addr(const char *name, sa_family_t *fam, npf_addr_t *addr)
    134 {
    135 	static const struct addrinfo hint = {
    136 		.ai_family = AF_UNSPEC,
    137 		.ai_flags = AI_NUMERICHOST
    138 	};
    139 	struct addrinfo *ai;
    140 	int ret;
    141 
    142 	ret = getaddrinfo(name, NULL, &hint, &ai);
    143 	if (ret) {
    144 		yyerror("cannot parse '%s' (%s)", name, gai_strerror(ret));
    145 		return false;
    146 	}
    147 	if (fam) {
    148 		*fam = ai->ai_family;
    149 	}
    150 	if (!npfctl_copy_address(*fam, addr, ai->ai_addr)) {
    151 		return false;
    152 	}
    153 	freeaddrinfo(ai);
    154 	return true;
    155 }
    156 
    157 static bool
    158 npfctl_parse_mask(const char *s, sa_family_t fam, npf_netmask_t *mask)
    159 {
    160 	char *ep = NULL;
    161 	npf_addr_t addr;
    162 	uint8_t *ap;
    163 
    164 	if (s) {
    165 		errno = 0;
    166 		*mask = (npf_netmask_t)strtol(s, &ep, 0);
    167 		if (*ep == '\0' && s != ep && errno != ERANGE)
    168 			return true;
    169 		if (!npfctl_parse_fam_addr(s, &fam, &addr))
    170 			return false;
    171 	}
    172 
    173 	assert(fam == AF_INET || fam == AF_INET6);
    174 	*mask = NPF_NO_NETMASK;
    175 	if (ep == NULL) {
    176 		return true;
    177 	}
    178 
    179 	ap = addr.word8 + (*mask / 8) - 1;
    180 	while (ap >= addr.word8) {
    181 		for (int j = 8; j > 0; j--) {
    182 			if (*ap & 1)
    183 				return true;
    184 			*ap >>= 1;
    185 			(*mask)--;
    186 			if (*mask == 0)
    187 				return true;
    188 		}
    189 		ap--;
    190 	}
    191 	return true;
    192 }
    193 
    194 /*
    195  * npfctl_parse_fam_addr_mask: return address family, address and mask.
    196  *
    197  * => Mask is optional and can be NULL.
    198  * => Returns true on success or false if unable to parse.
    199  */
    200 npfvar_t *
    201 npfctl_parse_fam_addr_mask(const char *addr, const char *mask,
    202     unsigned long *nummask)
    203 {
    204 	fam_addr_mask_t fam;
    205 
    206 	memset(&fam, 0, sizeof(fam));
    207 
    208 	if (!npfctl_parse_fam_addr(addr, &fam.fam_family, &fam.fam_addr))
    209 		return NULL;
    210 
    211 	/*
    212 	 * Note: both mask and nummask may be NULL.  In such case,
    213 	 * npfctl_parse_mask() will handle and will set full mask.
    214 	 */
    215 	if (nummask) {
    216 		fam.fam_mask = *nummask;
    217 	} else if (!npfctl_parse_mask(mask, fam.fam_family, &fam.fam_mask)) {
    218 		return NULL;
    219 	}
    220 	return npfvar_create_element(NPFVAR_FAM, &fam, sizeof(fam));
    221 }
    222 
    223 npfvar_t *
    224 npfctl_parse_table_id(const char *name)
    225 {
    226 	u_int tid;
    227 
    228 	tid = npfctl_table_getid(name);
    229 	if (tid == (unsigned)-1) {
    230 		yyerror("table '%s' is not defined", name);
    231 		return NULL;
    232 	}
    233 	return npfvar_create_element(NPFVAR_TABLE, &tid, sizeof(u_int));
    234 }
    235 
    236 /*
    237  * npfctl_parse_port_range: create a port-range variable.  Note that the
    238  * passed port numbers should be in host byte order.
    239  */
    240 npfvar_t *
    241 npfctl_parse_port_range(in_port_t s, in_port_t e)
    242 {
    243 	port_range_t pr;
    244 
    245 	pr.pr_start = htons(s);
    246 	pr.pr_end = htons(e);
    247 
    248 	return npfvar_create_element(NPFVAR_PORT_RANGE, &pr, sizeof(pr));
    249 }
    250 
    251 npfvar_t *
    252 npfctl_parse_port_range_variable(const char *v)
    253 {
    254 	npfvar_t *vp = npfvar_lookup(v);
    255 	size_t count = npfvar_get_count(vp);
    256 	npfvar_t *pvp = npfvar_create();
    257 	port_range_t *pr;
    258 	in_port_t p;
    259 
    260 	for (size_t i = 0; i < count; i++) {
    261 		int type = npfvar_get_type(vp, i);
    262 		void *data = npfvar_get_data(vp, type, i);
    263 
    264 		switch (type) {
    265 		case NPFVAR_IDENTIFIER:
    266 		case NPFVAR_STRING:
    267 			p = npfctl_portno(data);
    268 			npfvar_add_elements(pvp, npfctl_parse_port_range(p, p));
    269 			break;
    270 		case NPFVAR_PORT_RANGE:
    271 			pr = data;
    272 			npfvar_add_element(pvp, NPFVAR_PORT_RANGE, pr,
    273 			    sizeof(*pr));
    274 			break;
    275 		case NPFVAR_NUM:
    276 			p = *(unsigned long *)data;
    277 			npfvar_add_elements(pvp, npfctl_parse_port_range(p, p));
    278 			break;
    279 		default:
    280 			yyerror("wrong variable '%s' type '%s' for port range",
    281 			    v, npfvar_type(type));
    282 			npfvar_destroy(pvp);
    283 			return NULL;
    284 		}
    285 	}
    286 	return pvp;
    287 }
    288 
    289 npfvar_t *
    290 npfctl_parse_ifnet(const char *ifname, const int family)
    291 {
    292 	struct ifaddrs *ifa;
    293 	ifnet_addr_t ifna;
    294 	npfvar_t *vpa;
    295 
    296 	if (ifs_list == NULL && getifaddrs(&ifs_list) == -1) {
    297 		err(EXIT_FAILURE, "getifaddrs");
    298 	}
    299 
    300 	vpa = npfvar_create();
    301 	ifna.ifna_name = estrdup(ifname);
    302 	ifna.ifna_addrs = vpa;
    303 	ifna.ifna_index = npfctl_find_ifindex(ifname);
    304 	assert(ifna.ifna_index != 0);
    305 
    306 	for (ifa = ifs_list; ifa != NULL; ifa = ifa->ifa_next) {
    307 		fam_addr_mask_t fam;
    308 		struct sockaddr *sa;
    309 
    310 		if (strcmp(ifa->ifa_name, ifname) != 0)
    311 			continue;
    312 
    313 		if ((ifa->ifa_flags & IFF_UP) == 0)
    314 			warnx("interface '%s' is down", ifname);
    315 
    316 		sa = ifa->ifa_addr;
    317 		if (sa->sa_family != AF_INET && sa->sa_family != AF_INET6)
    318 			continue;
    319 		if (family != AF_UNSPEC && sa->sa_family != family)
    320 			continue;
    321 
    322 		memset(&fam, 0, sizeof(fam));
    323 		fam.fam_family = sa->sa_family;
    324 		fam.fam_ifindex = ifna.ifna_index;
    325 
    326 		if (!npfctl_copy_address(sa->sa_family, &fam.fam_addr, sa))
    327 			goto out;
    328 
    329 		if (!npfctl_parse_mask(NULL, fam.fam_family, &fam.fam_mask))
    330 			goto out;
    331 
    332 		if (!npfvar_add_element(vpa, NPFVAR_FAM, &fam, sizeof(fam)))
    333 			goto out;
    334 	}
    335 	if (npfvar_get_count(vpa) == 0) {
    336 		yyerror("no addresses matched for interface '%s'", ifname);
    337 		goto out;
    338 	}
    339 
    340 	return npfvar_create_element(NPFVAR_INTERFACE, &ifna, sizeof(ifna));
    341 out:
    342 	npfvar_destroy(ifna.ifna_addrs);
    343 	return NULL;
    344 }
    345 
    346 bool
    347 npfctl_parse_cidr(char *cidr, fam_addr_mask_t *fam, int *alen)
    348 {
    349 	char *mask, *p;
    350 
    351 	p = strchr(cidr, '\n');
    352 	if (p) {
    353 		*p = '\0';
    354 	}
    355 	mask = strchr(cidr, '/');
    356 	if (mask) {
    357 		*mask++ = '\0';
    358 	}
    359 
    360 	memset(fam, 0, sizeof(*fam));
    361 	if (!npfctl_parse_fam_addr(cidr, &fam->fam_family, &fam->fam_addr)) {
    362 		return false;
    363 	}
    364 	if (!npfctl_parse_mask(mask, fam->fam_family, &fam->fam_mask)) {
    365 		return false;
    366 	}
    367 	switch (fam->fam_family) {
    368 	case AF_INET:
    369 		*alen = sizeof(struct in_addr);
    370 		break;
    371 	case AF_INET6:
    372 		*alen = sizeof(struct in6_addr);
    373 		break;
    374 	default:
    375 		return false;
    376 	}
    377 	return true;
    378 }
    379 
    380 int
    381 npfctl_protono(const char *proto)
    382 {
    383 	struct protoent *pe;
    384 
    385 	pe = getprotobyname(proto);
    386 	if (pe == NULL) {
    387 		yyerror("unknown protocol '%s'", proto);
    388 		return -1;
    389 	}
    390 	return pe->p_proto;
    391 }
    392 
    393 /*
    394  * npfctl_portno: convert port identifier (string) to a number.
    395  *
    396  * => Returns port number in host byte order.
    397  */
    398 in_port_t
    399 npfctl_portno(const char *port)
    400 {
    401 	struct addrinfo *ai, *rai;
    402 	in_port_t p = 0;
    403 	int e;
    404 
    405 	e = getaddrinfo(NULL, port, NULL, &rai);
    406 	if (e != 0) {
    407 		yyerror("invalid port name '%s' (%s)", port, gai_strerror(e));
    408 		return 0;
    409 	}
    410 
    411 	for (ai = rai; ai; ai = ai->ai_next) {
    412 		switch (ai->ai_family) {
    413 		case AF_INET: {
    414 			struct sockaddr_in *sin = (void *)ai->ai_addr;
    415 			p = sin->sin_port;
    416 			goto out;
    417 		}
    418 		case AF_INET6: {
    419 			struct sockaddr_in6 *sin6 = (void *)ai->ai_addr;
    420 			p = sin6->sin6_port;
    421 			goto out;
    422 		}
    423 		default:
    424 			break;
    425 		}
    426 	}
    427 out:
    428 	freeaddrinfo(rai);
    429 	return ntohs(p);
    430 }
    431 
    432 npfvar_t *
    433 npfctl_parse_tcpflag(const char *s)
    434 {
    435 	uint8_t tfl = 0;
    436 
    437 	while (*s) {
    438 		switch (*s) {
    439 		case 'F': tfl |= TH_FIN; break;
    440 		case 'S': tfl |= TH_SYN; break;
    441 		case 'R': tfl |= TH_RST; break;
    442 		case 'P': tfl |= TH_PUSH; break;
    443 		case 'A': tfl |= TH_ACK; break;
    444 		case 'U': tfl |= TH_URG; break;
    445 		case 'E': tfl |= TH_ECE; break;
    446 		case 'W': tfl |= TH_CWR; break;
    447 		default:
    448 			yyerror("invalid flag '%c'", *s);
    449 			return NULL;
    450 		}
    451 		s++;
    452 	}
    453 	return npfvar_create_element(NPFVAR_TCPFLAG, &tfl, sizeof(tfl));
    454 }
    455 
    456 uint8_t
    457 npfctl_icmptype(int proto, const char *type)
    458 {
    459 #ifdef __NetBSD__
    460 	uint8_t ul;
    461 
    462 	switch (proto) {
    463 	case IPPROTO_ICMP:
    464 		for (ul = 0; icmp_type[ul]; ul++)
    465 			if (strcmp(icmp_type[ul], type) == 0)
    466 				return ul;
    467 		break;
    468 	case IPPROTO_ICMPV6:
    469 		for (ul = 0; icmp6_type_err[ul]; ul++)
    470 			if (strcmp(icmp6_type_err[ul], type) == 0)
    471 				return ul;
    472 		for (ul = 0; icmp6_type_info[ul]; ul++)
    473 			if (strcmp(icmp6_type_info[ul], type) == 0)
    474 				return ul + 128;
    475 		break;
    476 	default:
    477 		assert(false);
    478 	}
    479 #endif
    480 	yyerror("unknown icmp-type %s", type);
    481 	return ~0;
    482 }
    483 
    484 uint8_t
    485 npfctl_icmpcode(int proto, uint8_t type, const char *code)
    486 {
    487 #ifdef __NetBSD__
    488 	const char * const *arr;
    489 
    490 	switch (proto) {
    491 	case IPPROTO_ICMP:
    492 		switch (type) {
    493 		case ICMP_ECHOREPLY:
    494 		case ICMP_SOURCEQUENCH:
    495 		case ICMP_ALTHOSTADDR:
    496 		case ICMP_ECHO:
    497 		case ICMP_ROUTERSOLICIT:
    498 		case ICMP_TSTAMP:
    499 		case ICMP_TSTAMPREPLY:
    500 		case ICMP_IREQ:
    501 		case ICMP_IREQREPLY:
    502 		case ICMP_MASKREQ:
    503 		case ICMP_MASKREPLY:
    504 			arr = icmp_code_none;
    505 			break;
    506 		case ICMP_ROUTERADVERT:
    507 			arr = icmp_code_routeradvert;
    508 			break;
    509 		case ICMP_UNREACH:
    510 			arr = icmp_code_unreach;
    511 			break;
    512 		case ICMP_REDIRECT:
    513 			arr = icmp_code_redirect;
    514 			break;
    515 		case ICMP_TIMXCEED:
    516 			arr = icmp_code_timxceed;
    517 			break;
    518 		case ICMP_PARAMPROB:
    519 			arr = icmp_code_paramprob;
    520 			break;
    521 		case ICMP_PHOTURIS:
    522 			arr = icmp_code_photuris;
    523 			break;
    524 		default:
    525 			yyerror("unknown icmp-type %d while parsing code %s",
    526 				type, code);
    527 			return ~0;
    528 		}
    529 		break;
    530 	case IPPROTO_ICMPV6:
    531 		switch (type) {
    532 		case ICMP6_DST_UNREACH:
    533 			arr = icmp6_code_unreach;
    534 			break;
    535 		case ICMP6_TIME_EXCEEDED:
    536 			arr = icmp6_code_timxceed;
    537 			break;
    538 		case ICMP6_PARAM_PROB:
    539 			arr = icmp6_code_paramprob;
    540 			break;
    541 		case ICMP6_PACKET_TOO_BIG:
    542 		/* code-less info ICMPs */
    543 		case ICMP6_ECHO_REQUEST:
    544 		case ICMP6_ECHO_REPLY:
    545 		case MLD_LISTENER_QUERY:
    546 		case MLD_LISTENER_REPORT:
    547 		case MLD_LISTENER_DONE:
    548 		case ND_ROUTER_SOLICIT:
    549 		case ND_ROUTER_ADVERT:
    550 		case ND_NEIGHBOR_SOLICIT:
    551 		case ND_NEIGHBOR_ADVERT:
    552 		case ND_REDIRECT:
    553 			arr = icmp6_code_none;
    554 			break;
    555 		/* XXX TODO: info ICMPs with code values */
    556 		default:
    557 			yyerror("unknown icmp-type %d while parsing code %s",
    558 				type, code);
    559 			return ~0;
    560 		}
    561 		break;
    562 	default:
    563 		assert(false);
    564 	}
    565 
    566 	for (uint8_t ul = 0; arr[ul]; ul++) {
    567 		if (strcmp(arr[ul], code) == 0)
    568 			return ul;
    569 	}
    570 #endif
    571 	yyerror("unknown code %s for icmp-type %d", code, type);
    572 	return ~0;
    573 }
    574 
    575 npfvar_t *
    576 npfctl_parse_icmp(int proto, int type, int code)
    577 {
    578 	npfvar_t *vp = npfvar_create();
    579 
    580 	if (!npfvar_add_element(vp, NPFVAR_ICMP, &type, sizeof(type)))
    581 		goto out;
    582 
    583 	if (!npfvar_add_element(vp, NPFVAR_ICMP, &code, sizeof(code)))
    584 		goto out;
    585 
    586 	return vp;
    587 out:
    588 	npfvar_destroy(vp);
    589 	return NULL;
    590 }
    591 
    592 /*
    593  * npfctl_npt66_calcadj: calculate the adjustment for NPTv6 as per RFC 6296.
    594  */
    595 uint16_t
    596 npfctl_npt66_calcadj(npf_netmask_t len, const npf_addr_t *pref_in,
    597     const npf_addr_t *pref_out)
    598 {
    599 	const uint16_t *addr6_in = (const uint16_t *)pref_in;
    600 	const uint16_t *addr6_out = (const uint16_t *)pref_out;
    601 	unsigned i, remnant, wordmask, preflen = len >> 4;
    602 	uint32_t adj, isum = 0, osum = 0;
    603 
    604 	/*
    605 	 * Extract the bits within a 16-bit word (when prefix length is
    606 	 * not dividable by 16) and include them into the sum.
    607 	 */
    608 	remnant = len - (preflen << 4);
    609 	wordmask = (1U << remnant) - 1;
    610 	assert(wordmask == 0 || (len % 16) != 0);
    611 
    612 	/* Inner prefix - sum and fold. */
    613 	for (i = 0; i < preflen; i++) {
    614 		isum += addr6_in[i];
    615 	}
    616 	isum += addr6_in[i] & wordmask;
    617 	while (isum >> 16) {
    618 		isum = (isum >> 16) + (isum & 0xffff);
    619 	}
    620 
    621 	/* Outer prefix - sum and fold. */
    622 	for (i = 0; i < preflen; i++) {
    623 		osum += addr6_out[i];
    624 	}
    625 	osum += addr6_out[i] & wordmask;
    626 	while (osum >> 16) {
    627 		osum = (osum >> 16) + (osum & 0xffff);
    628 	}
    629 
    630 	/* Calculate 1's complement difference. */
    631 	adj = isum + ~osum;
    632 	while (adj >> 16) {
    633 		adj = (adj >> 16) + (adj & 0xffff);
    634 	}
    635 	return (uint16_t)adj;
    636 }
    637