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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <stdio.h>
#include <stdlib.h>
#include "alloc-util.h"
#include "bpf-firewall.h"
#include "extract-word.h"
#include "hostname-util.h"
#include "ip-address-access.h"
#include "parse-util.h"
#include "string-util.h"
int config_parse_ip_address_access(
const char *unit,
const char *filename,
unsigned line,
const char *section,
unsigned section_line,
const char *lvalue,
int ltype,
const char *rvalue,
void *data,
void *userdata) {
IPAddressAccessItem **list = data;
const char *p;
int r;
assert(list);
if (isempty(rvalue)) {
*list = ip_address_access_free_all(*list);
return 0;
}
p = rvalue;
for (;;) {
_cleanup_free_ IPAddressAccessItem *a = NULL;
_cleanup_free_ char *word = NULL;
r = extract_first_word(&p, &word, NULL, 0);
if (r == 0)
break;
if (r == -ENOMEM)
return log_oom();
if (r < 0) {
log_syntax(unit, LOG_WARNING, filename, line, r, "Invalid syntax, ignoring: %s", rvalue);
break;
}
a = new0(IPAddressAccessItem, 1);
if (!a)
return log_oom();
if (streq(word, "any")) {
/* "any" is a shortcut for 0.0.0.0/0 and ::/0 */
a->family = AF_INET;
LIST_APPEND(items, *list, a);
a = new0(IPAddressAccessItem, 1);
if (!a)
return log_oom();
a->family = AF_INET6;
} else if (is_localhost(word)) {
/* "localhost" is a shortcut for 127.0.0.0/8 and ::1/128 */
a->family = AF_INET;
a->address.in.s_addr = htobe32(0x7f000000);
a->prefixlen = 8;
LIST_APPEND(items, *list, a);
a = new0(IPAddressAccessItem, 1);
if (!a)
return log_oom();
a->family = AF_INET6;
a->address.in6 = (struct in6_addr) IN6ADDR_LOOPBACK_INIT;
a->prefixlen = 128;
} else if (streq(word, "link-local")) {
/* "link-local" is a shortcut for 169.254.0.0/16 and fe80::/64 */
a->family = AF_INET;
a->address.in.s_addr = htobe32((UINT32_C(169) << 24 | UINT32_C(254) << 16));
a->prefixlen = 16;
LIST_APPEND(items, *list, a);
a = new0(IPAddressAccessItem, 1);
if (!a)
return log_oom();
a->family = AF_INET6;
a->address.in6 = (struct in6_addr) {
.s6_addr32[0] = htobe32(0xfe800000)
};
a->prefixlen = 64;
} else if (streq(word, "multicast")) {
/* "multicast" is a shortcut for 224.0.0.0/4 and ff00::/8 */
a->family = AF_INET;
a->address.in.s_addr = htobe32((UINT32_C(224) << 24));
a->prefixlen = 4;
LIST_APPEND(items, *list, a);
a = new0(IPAddressAccessItem, 1);
if (!a)
return log_oom();
a->family = AF_INET6;
a->address.in6 = (struct in6_addr) {
.s6_addr32[0] = htobe32(0xff000000)
};
a->prefixlen = 8;
} else {
r = in_addr_prefix_from_string_auto(word, &a->family, &a->address, &a->prefixlen);
if (r < 0) {
log_syntax(unit, LOG_WARNING, filename, line, r, "Address prefix is invalid, ignoring assignment: %s", word);
return 0;
}
}
LIST_APPEND(items, *list, a);
a = NULL;
}
*list = ip_address_access_reduce(*list);
return 0;
}
IPAddressAccessItem* ip_address_access_free_all(IPAddressAccessItem *first) {
IPAddressAccessItem *next, *p = first;
while (p) {
next = p->items_next;
free(p);
p = next;
}
return NULL;
}
IPAddressAccessItem* ip_address_access_reduce(IPAddressAccessItem *first) {
IPAddressAccessItem *a, *b, *tmp;
int r;
/* Drops all entries from the list that are covered by another entry in full, thus removing all redundant
* entries. */
LIST_FOREACH_SAFE(items, a, tmp, first) {
/* Drop irrelevant bits */
(void) in_addr_mask(a->family, &a->address, a->prefixlen);
LIST_FOREACH(items, b, first) {
if (a == b)
continue;
if (a->family != b->family)
continue;
if (b->prefixlen > a->prefixlen)
continue;
r = in_addr_prefix_covers(b->family,
&b->address,
b->prefixlen,
&a->address);
if (r > 0) {
/* b covers a fully, then let's drop a */
LIST_REMOVE(items, first, a);
free(a);
break;
}
}
}
return first;
}
bool ip_address_access_item_is_any(IPAddressAccessItem *first) {
/* Check for exactly two entries */
if (!first || !first->items_next || first->items_next->items_next)
return false;
/* Check both entries cover the full range */
if (first->prefixlen != 0 || first->items_next->prefixlen != 0)
return false;
/* Check that one of them is the IPv4 and the other IPv6 */
if (!((first->family == AF_INET && first->items_next->family == AF_INET6) ||
(first->family == AF_INET6 && first->items_next->family == AF_INET)))
return false;
/* No need to check the actual addresses, they don't matter if the prefix is zero */
return true;
}
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