[secnet] / ipaddr.c

/* The 'ipset' data structure and related algorithms in this file were
   inspired by the 'ipaddr.py' library from Cendio Systems AB. */

#include "secnet.h"
#include <limits.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include "ipaddr.h"

#define DEFAULT_ALLOC 2
#define EXTEND_ALLOC_BY 4

struct subnet_list *subnet_list_new(void)
{
    struct subnet_list *r;
    r=safe_malloc(sizeof(*r),"subnet_list_new:list");
    r->entries=0;
    r->alloc=DEFAULT_ALLOC;
    r->list=safe_malloc_ary(sizeof(*r->list),r->alloc,"subnet_list_new:data");
    return r;
}

void subnet_list_free(struct subnet_list *a)
{
    if (a->list) free(a->list);
    free(a);
}

static void subnet_list_set_len(struct subnet_list *a, uint32_t l)
{
    struct subnet *nd;
    uint32_t na;

    if (l>a->alloc) {
	assert(a->alloc < (int)(INT_MAX/sizeof(*nd))-EXTEND_ALLOC_BY);
	na=a->alloc+EXTEND_ALLOC_BY;
	nd=realloc(a->list,sizeof(*nd)*na);
	if (!nd) {
	    fatal_perror("subnet_list_set_len: realloc");
	}
	a->alloc=na;
	a->list=nd;
    }
    a->entries=l;
}

void subnet_list_append(struct subnet_list *a, uint32_t prefix, uint32_t len)
{
    struct subnet *sn;
    assert(a->entries < INT_MAX);
    subnet_list_set_len(a,a->entries+1);
    sn=&a->list[a->entries-1];
    sn->prefix=prefix;
    sn->len=len;
    sn->mask=len?(0xffffffff << (32-len)):0;
}

struct ipset *ipset_new(void)
{
    struct ipset *r;
    r=safe_malloc(sizeof(*r),"ipset_new:set");
    r->l=0;
    r->a=DEFAULT_ALLOC;
    r->d=safe_malloc(sizeof(*r->d)*r->a,"ipset_new:data");
    return r;
}

void ipset_free(struct ipset *a)
{
    if (a->d) free(a->d);
    free(a);
}

#ifdef DEBUG
static void ipset_dump(struct ipset *a, string_t name)
{
    uint32_t i;

    printf("%s: ",name);
    for (i=0; i<a->l; i++) {
	printf("[%08x-%08x] ",a->d[i].a,a->d[i].b);
    }
    printf("\n");
}
#endif

struct ipset *ipset_from_subnet(struct subnet s)
{
    struct ipset *r;

    r=ipset_new();
    r->l=1;
    r->d[0].a=s.prefix;
    r->d[0].b=s.prefix | (~s.mask);
    return r;
}

struct ipset *ipset_from_subnet_list(struct subnet_list *l)
{
    struct ipset *r, *a, *b;
    uint32_t i;

    r=ipset_new();
    for (i=0; i<l->entries; i++) {
	a=ipset_from_subnet(l->list[i]);
	b=ipset_union(r,a);
	ipset_free(a);
	ipset_free(r);
	r=b;
    }
    return r;
}

static void ipset_set_len(struct ipset *a, uint32_t l)
{
    struct iprange *nd;
    uint32_t na;

    if (l>a->a) {
	assert(a->a < INT_MAX-EXTEND_ALLOC_BY);
	na=a->a+EXTEND_ALLOC_BY;
	nd=realloc(a->d,sizeof(*nd)*na);
	if (!nd) {
	    fatal_perror("ipset_set_len: realloc");
	}
	a->a=na;
	a->d=nd;
    }
    a->l=l;
}

static void ipset_append_range(struct ipset *a, struct iprange r)
{
    ipset_set_len(a,a->l+1);
    a->d[a->l-1]=r;
}

#define max(a,b) (a>b?a:b)
struct ipset *ipset_union(struct ipset *a, struct ipset *b)
{
    struct ipset *c;
    struct iprange r;
    uint32_t ia,ib;

    c=ipset_new();
    ia=0; ib=0;
    while (ia<a->l || ib<b->l) {
	if (ia<a->l)
	    if (ib<b->l)
		if (a->d[ia].a < b->d[ib].a)
		    r=a->d[ia++];
		else
		    r=b->d[ib++];
	    else
		r=a->d[ia++];
	else
	    r=b->d[ib++];

	if (c->l==0)
	    ipset_append_range(c,r);
	else if (r.a <= c->d[c->l-1].b+1)
	    /* Extends (or is consumed by) the last range */
	    c->d[c->l-1].b=max(c->d[c->l-1].b, r.b);
	else
	    ipset_append_range(c,r);
    }
    return c;
}

struct ipset *ipset_intersection(struct ipset *a, struct ipset *b)
{
    struct ipset *r;
    struct iprange ra, rb;
    uint32_t ia,ib;

    r=ipset_new();
    ia=0; ib=0;

    while (ia<a->l && ib<b->l) {
	ra=a->d[ia];
	rb=b->d[ib];
	if (ra.b < rb.a)
	    /* The first entry of a doesn't overlap with any part of b */
	    ia++;
	else if (ra.a > rb.b)
	    /* The first entry of b doesn't overlap with any part of a */
	    ib++;
	else {
	    /* Trim away any leading edges */
	    if (ra.a < rb.a)
		/* a starts before b */
		ra.a=rb.a;
	    else if (ra.a > rb.a)
		/* b starts before a */
		rb.a=ra.a;

	    /* Now the ranges start at the same point */
	    if (ra.b == rb.b) {
		/* The ranges are equal */
		ipset_append_range(r,ra);
		ia++;
		ib++;
	    } else if (ra.b < rb.b) {
		/* a is the smaller range */
		ipset_append_range(r,ra);
		ia++;
	    } else {
		/* y is the smaller range */
		ipset_append_range(r,rb);
		ib++;
	    }
	}
    }
    return r;
}

struct ipset *ipset_complement(struct ipset *a)
{
    struct ipset *r;
    struct iprange n;
    int64_t pre;
    uint32_t i,lo,hi;

    r=ipset_new();
    pre=-1;
    for (i=0; i<a->l; i++) {
	lo=a->d[i].a;
	hi=a->d[i].b;
	if (lo!=0) {
	    n.a=pre+1;
	    n.b=lo-1;
	    ipset_append_range(r,n);
	}
	pre=hi;
    }
    if (pre!=0xffffffff) {
	n.a=pre+1;
	n.b=0xffffffff;
	ipset_append_range(r,n);
    }
    return r;
}

/* Return a-b */
struct ipset *ipset_subtract(struct ipset *a, struct ipset *b)
{
    struct ipset *c, *r;
    c=ipset_complement(b);
    r=ipset_intersection(a,c);
    ipset_free(c);
    return r;
}

bool_t ipset_is_empty(struct ipset *a)
{
   return (a->l==0);
}

bool_t ipset_contains_addr(struct ipset *a, uint32_t addr)
{
    uint32_t i;
    struct iprange r;

    for (i=0; i<a->l; i++) {
	r=a->d[i];
	if (addr>=r.a && addr<=r.b) return True;
	if (addr<r.a) return False;
    }
    return False;
}

/* sub is a subset of super if it does not intersect with the complement 
   of super */
bool_t ipset_is_subset(struct ipset *super, struct ipset *sub)
{
    struct ipset *superc;
    struct ipset *inter;
    bool_t empty;

    superc=ipset_complement(super);
    inter=ipset_intersection(superc,sub);
    empty=ipset_is_empty(inter);
    ipset_free(inter);
    ipset_free(superc);
    return empty;
}

struct subnet_list *ipset_to_subnet_list(struct ipset *is)
{
    struct subnet_list *r;
    int64_t a,b,lobit,himask,lomask;
    int32_t bits;
    uint32_t i;

    r=subnet_list_new();
    for (i=0; i<is->l; i++) {
	a=is->d[i].a;
	b=is->d[i].b;

	lomask=1;
	lobit=1;
	himask=0xfffffffe;
	bits=32;
	while (a<=b) {
	    if ((a & lomask) != 0) {
		subnet_list_append(r,a,bits);
		a=a+lobit;
	    } else if ((b & lomask) != lomask) {
		subnet_list_append(r,b&himask,bits);
		b=b-lobit;
	    } else {
		lomask = (lomask << 1) | 1;
		lobit = (lobit << 1);
		himask = himask ^ lobit;
		bits = bits - 1;
		ASSERT(bits>=0);
	    }
	}
    }
    /* Sort the list? */
    return r;
}

/* The string buffer must be at least 16 bytes long */
string_t ipaddr_to_string(uint32_t addr)
{
    uint8_t a,b,c,d;
    string_t s;

    s=safe_malloc(16,"ipaddr_to_string");
    a=addr>>24;
    b=addr>>16;
    c=addr>>8;
    d=addr;
    snprintf(s, 16, "%d.%d.%d.%d", a, b, c, d);
    return s;
}

string_t subnet_to_string(struct subnet sn)
{
    uint32_t addr=sn.prefix;
    uint8_t a,b,c,d;
    string_t s;

    s=safe_malloc(19,"subnet_to_string");
    a=addr>>24;
    b=addr>>16;
    c=addr>>8;
    d=addr;
    snprintf(s, 19, "%d.%d.%d.%d/%d", a, b, c, d, sn.len);
    return s;
}

static struct subnet string_item_to_subnet(item_t *i, cstring_t desc,
					   bool_t *invert)
{
    struct subnet s;
    uint32_t a, b, c, d, n;
    uint32_t match;
    cstring_t in;

    *invert=False;

    /* i is not guaranteed to be a string */
    if (i->type!=t_string) {
	cfgfatal(i->loc,desc,"expecting a string (subnet specification)\n");
    }
    in=i->data.string;

    if (strcmp(in,"default")==0) {
	s.prefix=0;
	s.mask=0;
	s.len=0;
	return s;
    }

    if (*in=='!') {
	*invert=True;
	in++;
    }
    /* We expect strings of the form "a.b.c.d[/n]", i.e. the dots are
       NOT optional. The subnet mask is optional; if missing it is assumed
       to be /32. */
    match=sscanf(in,"%u.%u.%u.%u/%u", &a, &b, &c, &d, &n);
    if (match<4) {
	cfgfatal(i->loc,desc,"\"%s\" is not a valid "
		 "subnet specification\n",in);
    }
    if (match<5) {
	n=32;
    }
    if (a>255 || b>255 || c>255 || d>255 || n>32) {
	cfgfatal(i->loc,desc,"\"%s\": range error\n",in);
    }
    s.prefix=(a<<24)|(b<<16)|(c<<8)|(d);
    s.mask=n?(~0UL << (32-n)):0;
    s.len=n;
    if (s.prefix & ~s.mask) {
	cfgfatal(i->loc,desc,"\"%s\": prefix not fully contained "
		 "in mask\n",in);
    }
    return s;
}

uint32_t string_item_to_ipaddr(item_t *i, cstring_t desc)
{
    uint32_t a, b, c, d;
    uint32_t match;

    /* i is not guaranteed to be a string */
    if (i->type!=t_string) {
	cfgfatal(i->loc,desc,"expecting a string (IP address)\n");
    }

    match=sscanf(i->data.string,"%u.%u.%u.%u", &a, &b, &c, &d);
    if (match<4) {
	cfgfatal(i->loc,desc,"\"%s\" is not a valid "
		 "IP address\n",i->data.string);
    }
    if (a>255 || b>255 || c>255 || d>255) {
	cfgfatal(i->loc,desc,"\"%s\": range error\n",i->data.string);
    }
    return (a<<24)|(b<<16)|(c<<8)|(d);
}

struct ipset *string_list_to_ipset(list_t *l, struct cloc loc,
				   cstring_t module, cstring_t param)
{
    struct ipset *r, *n, *isn;
    uint32_t e,i;
    item_t *item;
    bool_t inv;

    r=ipset_new();
    e=list_length(l);
    for (i=0; i<e; i++) {
	item=list_elem(l,i);
	isn=ipset_from_subnet(string_item_to_subnet(item,param,&inv));
	if (inv) {
	    n=ipset_subtract(r,isn);
	} else {
	    n=ipset_union(r,isn);
	}
	ipset_free(r);
	ipset_free(isn);
	r=n;
    }
    return r;
}
Commit	Line	Data
794f2398 SE	1	/* The 'ipset' data structure and related algorithms in this file were
	2	inspired by the 'ipaddr.py' library from Cendio Systems AB. */
	3
7138d0c5	4	#include "secnet.h"
59230b9b IJ	5	#include <limits.h>
59230b9b IJ	6	#include <assert.h>
7138d0c5	7	#include <stdio.h>
3b83c932	8	#include <string.h>
794f2398 SE	9	#include "ipaddr.h"
	10
	11	#define DEFAULT_ALLOC 2
	12	#define EXTEND_ALLOC_BY 4
	13
	14	struct subnet_list *subnet_list_new(void)
	15	{
	16	struct subnet_list *r;
	17	r=safe_malloc(sizeof(*r),"subnet_list_new:list");
	18	r->entries=0;
	19	r->alloc=DEFAULT_ALLOC;
bb9d0561	20	r->list=safe_malloc_ary(sizeof(*r->list),r->alloc,"subnet_list_new:data");
794f2398 SE	21	return r;
	22	}
	23
	24	void subnet_list_free(struct subnet_list *a)
	25	{
	26	if (a->list) free(a->list);
	27	free(a);
	28	}
	29
	30	static void subnet_list_set_len(struct subnet_list *a, uint32_t l)
	31	{
	32	struct subnet *nd;
	33	uint32_t na;
	34
	35	if (l>a->alloc) {
59230b9b	36	assert(a->alloc < (int)(INT_MAX/sizeof(*nd))-EXTEND_ALLOC_BY);
794f2398 SE	37	na=a->alloc+EXTEND_ALLOC_BY;
	38	nd=realloc(a->list,sizeof(nd)na);
	39	if (!nd) {
	40	fatal_perror("subnet_list_set_len: realloc");
	41	}
	42	a->alloc=na;
	43	a->list=nd;
	44	}
	45	a->entries=l;
	46	}
	47
	48	void subnet_list_append(struct subnet_list *a, uint32_t prefix, uint32_t len)
	49	{
	50	struct subnet *sn;
59230b9b	51	assert(a->entries < INT_MAX);
794f2398 SE	52	subnet_list_set_len(a,a->entries+1);
	53	sn=&a->list[a->entries-1];
	54	sn->prefix=prefix;
	55	sn->len=len;
	56	sn->mask=len?(0xffffffff << (32-len)):0;
	57	}
7138d0c5	58
794f2398 SE	59	struct ipset *ipset_new(void)
	60	{
	61	struct ipset *r;
	62	r=safe_malloc(sizeof(*r),"ipset_new:set");
	63	r->l=0;
	64	r->a=DEFAULT_ALLOC;
	65	r->d=safe_malloc(sizeof(r->d)r->a,"ipset_new:data");
	66	return r;
	67	}
7138d0c5	68
794f2398	69	void ipset_free(struct ipset *a)
7138d0c5	70	{
794f2398 SE	71	if (a->d) free(a->d);
794f2398 SE	72	free(a);
7138d0c5 SE	73	}
7138d0c5 SE	74
794f2398 SE	75	#ifdef DEBUG
794f2398 SE	76	static void ipset_dump(struct ipset *a, string_t name)
7138d0c5 SE	77	{
7138d0c5 SE	78	uint32_t i;
794f2398 SE	79
	80	printf("%s: ",name);
	81	for (i=0; i<a->l; i++) {
	82	printf("[%08x-%08x] ",a->d[i].a,a->d[i].b);
7138d0c5	83	}
794f2398	84	printf("\n");
7138d0c5	85	}
794f2398	86	#endif
7138d0c5	87
794f2398	88	struct ipset *ipset_from_subnet(struct subnet s)
7138d0c5	89	{
794f2398 SE	90	struct ipset *r;
	91
	92	r=ipset_new();
	93	r->l=1;
	94	r->d[0].a=s.prefix;
	95	r->d[0].b=s.prefix \| (~s.mask);
	96	return r;
7138d0c5 SE	97	}
7138d0c5 SE	98
794f2398	99	struct ipset ipset_from_subnet_list(struct subnet_list l)
7138d0c5	100	{
794f2398	101	struct ipset r, a, *b;
7138d0c5 SE	102	uint32_t i;
7138d0c5 SE	103
794f2398 SE	104	r=ipset_new();
	105	for (i=0; i<l->entries; i++) {
	106	a=ipset_from_subnet(l->list[i]);
	107	b=ipset_union(r,a);
	108	ipset_free(a);
	109	ipset_free(r);
	110	r=b;
7138d0c5	111	}
794f2398	112	return r;
7138d0c5 SE	113	}
7138d0c5 SE	114
794f2398 SE	115	static void ipset_set_len(struct ipset *a, uint32_t l)
	116	{
	117	struct iprange *nd;
	118	uint32_t na;
	119
	120	if (l>a->a) {
59230b9b	121	assert(a->a < INT_MAX-EXTEND_ALLOC_BY);
794f2398 SE	122	na=a->a+EXTEND_ALLOC_BY;
	123	nd=realloc(a->d,sizeof(nd)na);
	124	if (!nd) {
	125	fatal_perror("ipset_set_len: realloc");
	126	}
	127	a->a=na;
	128	a->d=nd;
	129	}
	130	a->l=l;
	131	}
	132
	133	static void ipset_append_range(struct ipset *a, struct iprange r)
	134	{
	135	ipset_set_len(a,a->l+1);
	136	a->d[a->l-1]=r;
	137	}
	138
	139	#define max(a,b) (a>b?a:b)
	140	struct ipset ipset_union(struct ipset a, struct ipset *b)
	141	{
	142	struct ipset *c;
	143	struct iprange r;
	144	uint32_t ia,ib;
	145
	146	c=ipset_new();
	147	ia=0; ib=0;
	148	while (ia<a->l \|\| ib<b->l) {
	149	if (ia<a->l)
	150	if (ib<b->l)
	151	if (a->d[ia].a < b->d[ib].a)
	152	r=a->d[ia++];
	153	else
	154	r=b->d[ib++];
	155	else
	156	r=a->d[ia++];
	157	else
	158	r=b->d[ib++];
	159
	160	if (c->l==0)
	161	ipset_append_range(c,r);
	162	else if (r.a <= c->d[c->l-1].b+1)
	163	/* Extends (or is consumed by) the last range */
	164	c->d[c->l-1].b=max(c->d[c->l-1].b, r.b);
	165	else
	166	ipset_append_range(c,r);
	167	}
	168	return c;
	169	}
	170
	171	struct ipset ipset_intersection(struct ipset a, struct ipset *b)
	172	{
	173	struct ipset *r;
	174	struct iprange ra, rb;
	175	uint32_t ia,ib;
	176
	177	r=ipset_new();
	178	ia=0; ib=0;
	179
	180	while (ia<a->l && ib<b->l) {
	181	ra=a->d[ia];
	182	rb=b->d[ib];
	183	if (ra.b < rb.a)
	184	/* The first entry of a doesn't overlap with any part of b */
	185	ia++;
186	else if (ra.a > rb.b)
187	/* The first entry of b doesn't overlap with any part of a */
188	ib++;
189	else {
190	/* Trim away any leading edges */
191	if (ra.a < rb.a)
192	/* a starts before b */
193	ra.a=rb.a;
194	else if (ra.a > rb.a)
195	/* b starts before a */
196	rb.a=ra.a;
197
198	/* Now the ranges start at the same point */
199	if (ra.b == rb.b) {
200	/* The ranges are equal */
201	ipset_append_range(r,ra);
202	ia++;
203	ib++;
204	} else if (ra.b < rb.b) {
205	/* a is the smaller range */
206	ipset_append_range(r,ra);
207	ia++;
208	} else {
209	/* y is the smaller range */
210	ipset_append_range(r,rb);
211	ib++;
212	}
213	}
214	}
215	return r;
216	}
217
218	struct ipset ipset_complement(struct ipset a)
219	{
220	struct ipset *r;
221	struct iprange n;
222	int64_t pre;
223	uint32_t i,lo,hi;
224
225	r=ipset_new();
226	pre=-1;
227	for (i=0; i<a->l; i++) {
228	lo=a->d[i].a;
229	hi=a->d[i].b;
230	if (lo!=0) {
231	n.a=pre+1;
232	n.b=lo-1;
233	ipset_append_range(r,n);
234	}
235	pre=hi;
236	}
237	if (pre!=0xffffffff) {
238	n.a=pre+1;
239	n.b=0xffffffff;
240	ipset_append_range(r,n);
241	}
242	return r;
243	}
244
245	/* Return a-b */
246	struct ipset ipset_subtract(struct ipset a, struct ipset *b)
247	{
248	struct ipset c, r;
249	c=ipset_complement(b);
250	r=ipset_intersection(a,c);
251	ipset_free(c);
252	return r;
253	}
254
255	bool_t ipset_is_empty(struct ipset *a)
256	{
257	return (a->l==0);
258	}
259
260	bool_t ipset_contains_addr(struct ipset *a, uint32_t addr)
7138d0c5 SE	261	{
7138d0c5 SE	262	uint32_t i;
794f2398 SE	263	struct iprange r;
	264
	265	for (i=0; i<a->l; i++) {
	266	r=a->d[i];
	267	if (addr>=r.a && addr<=r.b) return True;
	268	if (addr<r.a) return False;
7138d0c5 SE	269	}
	270	return False;
	271	}
	272
794f2398 SE	273	/* sub is a subset of super if it does not intersect with the complement
	274	of super */
	275	bool_t ipset_is_subset(struct ipset super, struct ipset sub)
	276	{
	277	struct ipset *superc;
	278	struct ipset *inter;
	279	bool_t empty;
	280
	281	superc=ipset_complement(super);
	282	inter=ipset_intersection(superc,sub);
	283	empty=ipset_is_empty(inter);
	284	ipset_free(inter);
	285	ipset_free(superc);
	286	return empty;
	287	}
	288
	289	struct subnet_list ipset_to_subnet_list(struct ipset is)
	290	{
	291	struct subnet_list *r;
ff05a229 SE	292	int64_t a,b,lobit,himask,lomask;
ff05a229 SE	293	int32_t bits;
794f2398	294	uint32_t i;
794f2398 SE	295
	296	r=subnet_list_new();
	297	for (i=0; i<is->l; i++) {
	298	a=is->d[i].a;
	299	b=is->d[i].b;
	300
	301	lomask=1;
	302	lobit=1;
	303	himask=0xfffffffe;
	304	bits=32;
	305	while (a<=b) {
	306	if ((a & lomask) != 0) {
	307	subnet_list_append(r,a,bits);
	308	a=a+lobit;
	309	} else if ((b & lomask) != lomask) {
	310	subnet_list_append(r,b&himask,bits);
	311	b=b-lobit;
	312	} else {
	313	lomask = (lomask << 1) \| 1;
	314	lobit = (lobit << 1);
	315	himask = himask ^ lobit;
	316	bits = bits - 1;
	317	ASSERT(bits>=0);
	318	}
	319	}
	320	}
	321	/* Sort the list? */
	322	return r;
	323	}
	324
7138d0c5 SE	325	/* The string buffer must be at least 16 bytes long */
	326	string_t ipaddr_to_string(uint32_t addr)
	327	{
	328	uint8_t a,b,c,d;
	329	string_t s;
	330
	331	s=safe_malloc(16,"ipaddr_to_string");
	332	a=addr>>24;
	333	b=addr>>16;
	334	c=addr>>8;
	335	d=addr;
	336	snprintf(s, 16, "%d.%d.%d.%d", a, b, c, d);
	337	return s;
	338	}
	339
794f2398	340	string_t subnet_to_string(struct subnet sn)
7138d0c5	341	{
794f2398	342	uint32_t addr=sn.prefix;
7138d0c5 SE	343	uint8_t a,b,c,d;
7138d0c5 SE	344	string_t s;
7138d0c5 SE	345
	346	s=safe_malloc(19,"subnet_to_string");
	347	a=addr>>24;
	348	b=addr>>16;
	349	c=addr>>8;
	350	d=addr;
794f2398 SE	351	snprintf(s, 19, "%d.%d.%d.%d/%d", a, b, c, d, sn.len);
	352	return s;
	353	}
	354
fe5e9cc4	355	static struct subnet string_item_to_subnet(item_t *i, cstring_t desc,
794f2398 SE	356	bool_t *invert)
	357	{
	358	struct subnet s;
	359	uint32_t a, b, c, d, n;
	360	uint32_t match;
fe5e9cc4	361	cstring_t in;
794f2398 SE	362
	363	*invert=False;
	364
	365	/* i is not guaranteed to be a string */
	366	if (i->type!=t_string) {
	367	cfgfatal(i->loc,desc,"expecting a string (subnet specification)\n");
	368	}
	369	in=i->data.string;
	370
	371	if (strcmp(in,"default")==0) {
	372	s.prefix=0;
	373	s.mask=0;
	374	s.len=0;
	375	return s;
	376	}
	377
	378	if (*in=='!') {
	379	*invert=True;
	380	in++;
	381	}
	382	/* We expect strings of the form "a.b.c.d[/n]", i.e. the dots are
	383	NOT optional. The subnet mask is optional; if missing it is assumed
	384	to be /32. */
	385	match=sscanf(in,"%u.%u.%u.%u/%u", &a, &b, &c, &d, &n);
	386	if (match<4) {
	387	cfgfatal(i->loc,desc,"\"%s\" is not a valid "
	388	"subnet specification\n",in);
	389	}
	390	if (match<5) {
	391	n=32;
7138d0c5	392	}
794f2398 SE	393	if (a>255 \|\| b>255 \|\| c>255 \|\| d>255 \|\| n>32) {
	394	cfgfatal(i->loc,desc,"\"%s\": range error\n",in);
	395	}
	396	s.prefix=(a<<24)\|(b<<16)\|(c<<8)\|(d);
	397	s.mask=n?(~0UL << (32-n)):0;
	398	s.len=n;
	399	if (s.prefix & ~s.mask) {
	400	cfgfatal(i->loc,desc,"\"%s\": prefix not fully contained "
	401	"in mask\n",in);
7138d0c5	402	}
7138d0c5 SE	403	return s;
7138d0c5 SE	404	}
794f2398	405
fe5e9cc4	406	uint32_t string_item_to_ipaddr(item_t *i, cstring_t desc)
794f2398 SE	407	{
	408	uint32_t a, b, c, d;
	409	uint32_t match;
	410
	411	/* i is not guaranteed to be a string */
	412	if (i->type!=t_string) {
	413	cfgfatal(i->loc,desc,"expecting a string (IP address)\n");
	414	}
	415
	416	match=sscanf(i->data.string,"%u.%u.%u.%u", &a, &b, &c, &d);
	417	if (match<4) {
	418	cfgfatal(i->loc,desc,"\"%s\" is not a valid "
	419	"IP address\n",i->data.string);
	420	}
	421	if (a>255 \|\| b>255 \|\| c>255 \|\| d>255) {
	422	cfgfatal(i->loc,desc,"\"%s\": range error\n",i->data.string);
	423	}
	424	return (a<<24)\|(b<<16)\|(c<<8)\|(d);
	425	}
	426
	427	struct ipset string_list_to_ipset(list_t l, struct cloc loc,
fe5e9cc4	428	cstring_t module, cstring_t param)
794f2398 SE	429	{
	430	struct ipset r, n, *isn;
	431	uint32_t e,i;
	432	item_t *item;
	433	bool_t inv;
	434
	435	r=ipset_new();
	436	e=list_length(l);
	437	for (i=0; i<e; i++) {
	438	item=list_elem(l,i);
	439	isn=ipset_from_subnet(string_item_to_subnet(item,param,&inv));
	440	if (inv) {
	441	n=ipset_subtract(r,isn);
	442	} else {
	443	n=ipset_union(r,isn);
	444	}
	445	ipset_free(r);
	446	ipset_free(isn);
	447	r=n;
	448	}
	449	return r;
	450	}