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/* $Id: rbldnsd_acl.c,v 1.7 2007-10-07 14:01:44 mjt Exp $
* ACL (Access Control Lists) implementation for rbldnsd.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include "rbldnsd.h"
struct dsdata {
struct ip4trie trie;
const char *def_rr;
const char *def_action;
};
/* special cases for pseudo-RRs */
static const struct {
const char *name;
unsigned long rr;
} keywords[] = {
/* ignore (don't answer) queries from this IP */
#define RR_IGNORE 1
{ "ignore", RR_IGNORE },
{ "blackhole", RR_IGNORE },
/* refuse *data* queries from this IP (but not metadata) */
#define RR_REFUSE 2
{ "refuse", RR_REFUSE },
/* pretend the zone is completely empty */
#define RR_EMPTY 3
{ "empty", RR_EMPTY },
/* a 'whitelist' entry: pretend this netrange isn't here */
#define RR_PASS 4
{ "pass", RR_PASS },
};
static void ds_acl_reset(struct dsdata *dsd, int UNUSED unused_freeall) {
memset(dsd, 0, sizeof(*dsd));
}
static void ds_acl_start(struct dataset *ds) {
ds->ds_dsd->def_rr = def_rr;
ds->ds_dsd->def_action = (char*)RR_IGNORE;
}
static const char *keyword(const char *s) {
const char *k, *p;
unsigned i;
if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z')))
return NULL;
for (i = 0; i < sizeof(keywords)/sizeof(keywords[0]); ++i)
for (k = keywords[i].name, p = s;;)
if ((*p >= 'A' && *p <= 'Z' ? *p - 'A' + 'a' : *p) != *k++)
break;
else if (!*++p || *p == ':' || ISSPACE(*p) || ISCOMMENT(*p))
return (const char *)(keywords[i].rr);
return NULL;
}
static int
ds_acl_parse_val(char *s, const char **rr_p, struct dsdata *dsd,
struct dsctx *dsc) {
int r;
if (*s == '=') {
if ((*rr_p = keyword(s+1)))
return 0;
dswarn(dsc, "invalid keyword");
return -1;
}
if (*s == ':' && (*rr_p = keyword(s+1)))
return 0;
r = parse_a_txt(s, rr_p, dsd->def_rr, dsc);
return r ? r : -1;
}
static int
ds_acl_line(struct dataset *ds, char *s, struct dsctx *dsc) {
struct dsdata *dsd = ds->ds_dsd;
ip4addr_t a;
int bits;
const char *rr;
int rrl;
struct ip4trie_node *node;
if (*s == ':' || *s == '=') {
if ((rrl = ds_acl_parse_val(s, &rr, dsd, dsc)) < 0)
return 1;
else if (!rrl)
dsd->def_action = rr;
else if (!(rr = mp_dmemdup(ds->ds_mp, rr, rrl)))
return 0;
dsd->def_rr = dsd->def_action = rr;
return 1;
}
if ((bits = ip4cidr(s, &a, &s)) <= 0 ||
(*s && !ISSPACE(*s) && !ISCOMMENT(*s) && *s != ':')) {
dswarn(dsc, "invalid address");
return 1;
}
if (accept_in_cidr)
a &= ip4mask(bits);
else if (a & ~ip4mask(bits)) {
dswarn(dsc, "invalid range (non-zero host part)");
return 1;
}
if (dsc->dsc_ip4maxrange && dsc->dsc_ip4maxrange <= ~ip4mask(bits)) {
dswarn(dsc, "too large range (%u) ignored (%u max)",
~ip4mask(bits) + 1, dsc->dsc_ip4maxrange);
return 1;
}
SKIPSPACE(s);
if (!*s || ISCOMMENT(*s))
rr = dsd->def_action;
else if ((rrl = ds_acl_parse_val(s, &rr, dsd, dsc)) < 0)
return 1;
else if (rrl && !(rr = mp_dmemdup(ds->ds_mp, rr, rrl)))
return 0;
node = ip4trie_addnode(&dsd->trie, a, bits, ds->ds_mp);
if (!node)
return 0;
if (node->ip4t_data) {
dswarn(dsc, "duplicated entry for %s/%d", ip4atos(a), bits);
return 1;
}
node->ip4t_data = rr;
++dsd->trie.ip4t_nents;
return 1;
}
static void ds_acl_finish(struct dataset *ds, struct dsctx *dsc) {
struct dsdata *dsd = ds->ds_dsd;
dsloaded(dsc, "ent=%u nodes=%u mem=%lu",
dsd->trie.ip4t_nents, dsd->trie.ip4t_nnodes,
(unsigned long)dsd->trie.ip4t_nnodes * sizeof(struct ip4trie_node));
}
int ds_acl_query(const struct dataset *ds, struct dnspacket *pkt) {
const struct sockaddr_in *sin = (const struct sockaddr_in *)pkt->p_peer;
const char *rr;
if (sin->sin_family != AF_INET || sizeof(*sin) > pkt->p_peerlen)
return 0;
rr = ip4trie_lookup(&ds->ds_dsd->trie, ntohl(sin->sin_addr.s_addr));
switch((unsigned long)rr) {
case 0: return 0;
case RR_IGNORE: return NSQUERY_IGNORE;
case RR_REFUSE: return NSQUERY_REFUSE;
case RR_EMPTY: return NSQUERY_EMPTY;
case RR_PASS: return 0;
}
if (!pkt->p_substrr) {
pkt->p_substrr = rr;
pkt->p_substds = ds;
}
return NSQUERY_ALWAYS;
}
/*definedstype(acl, DSTF_SPECIAL, "Access Control List dataset");*/
const struct dstype dataset_acl_type = {
"acl", DSTF_SPECIAL, sizeof(struct dsdata),
ds_acl_reset, ds_acl_start, ds_acl_line, ds_acl_finish,
NULL, NULL, "Access Control List dataset"
};
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