Merge pull request #18653 from yuwata/in-addr-prefix-nth

in-addr-util: fix in_addr_prefix_nth() and use the function to get ip address range in firewall-util

src/basic/in-addr-util.c

@@ -189,8 +189,8 @@ int in_addr_prefix_intersect(
 int in_addr_prefix_next(int family, union in_addr_union *u, unsigned prefixlen) {
         assert(u);
 
-        /* Increases the network part of an address by one. Returns
+        /* Increases the network part of an address by one. Returns 0 if that succeeds, or -ERANGE if
-         * positive if that succeeds, or -ERANGE if this overflows. */
+         * this overflows. */
 
         return in_addr_prefix_nth(family, u, prefixlen, 1);
 }
@@ -198,19 +198,17 @@ int in_addr_prefix_next(int family, union in_addr_union *u, unsigned prefixlen)
 /*
  * Calculates the nth prefix of size prefixlen starting from the address denoted by u.
  *
- * On success 1 will be returned and the calculated prefix will be available in
+ * On success 0 will be returned and the calculated prefix will be available in
- * u. In the case nth == 0 the input will be left unchanged and 1 will be returned.
+ * u. In case the calculation cannot be performed (invalid prefix length,
- * In case the calculation cannot be performed (invalid prefix length,
  * overflows would occur) -ERANGE is returned. If the address family given isn't
  * supported -EAFNOSUPPORT will be returned.
  *
- *
  * Examples:
- *   - in_addr_prefix_nth(AF_INET, 192.168.0.0, 24, 2), returns 1, writes 192.168.2.0 to u
+ *   - in_addr_prefix_nth(AF_INET, 192.168.0.0, 24, 2), returns 0, writes 192.168.2.0 to u
- *   - in_addr_prefix_nth(AF_INET, 192.168.0.0, 24, 0), returns 1, no data written
+ *   - in_addr_prefix_nth(AF_INET, 192.168.0.0, 24, 0), returns 0, no data written
  *   - in_addr_prefix_nth(AF_INET, 255.255.255.0, 24, 1), returns -ERANGE, no data written
  *   - in_addr_prefix_nth(AF_INET, 255.255.255.0, 0, 1), returns -ERANGE, no data written
- *   - in_addr_prefix_nth(AF_INET6, 2001:db8, 64, 0xff00) returns 1, writes 2001:0db8:0000:ff00:: to u
+ *   - in_addr_prefix_nth(AF_INET6, 2001:db8, 64, 0xff00) returns 0, writes 2001:0db8:0000:ff00:: to u
  */
 int in_addr_prefix_nth(int family, union in_addr_union *u, unsigned prefixlen, uint64_t nth) {
         assert(u);
@@ -218,13 +216,11 @@ int in_addr_prefix_nth(int family, union in_addr_union *u, unsigned prefixlen, u
         if (prefixlen <= 0)
                 return -ERANGE;
 
-        if (nth == 0)
-                return 1;
-
         if (family == AF_INET) {
                 uint32_t c, n, t;
+
                 if (prefixlen > 32)
-                        prefixlen = 32;
+                        return -ERANGE;
 
                 c = be32toh(u->in.s_addr);
 
@@ -238,44 +234,40 @@ int in_addr_prefix_nth(int family, union in_addr_union *u, unsigned prefixlen, u
 
                 n &= UINT32_C(0xFFFFFFFF) << (32 - prefixlen);
                 u->in.s_addr = htobe32(n);
-                return 1;
+                return 0;
         }
 
         if (family == AF_INET6) {
-                struct in6_addr result = {};
+                bool overflow = false;
-                uint8_t overflow = 0;
-                uint64_t delta;  /* this assumes that we only ever have to up to 1<<64 subnets */
-                unsigned start_byte = (prefixlen - 1) / 8;
 
                 if (prefixlen > 128)
-                        prefixlen = 128;
-
-                /* First calculate what we have to add */
-                delta = nth << ((128 - prefixlen) % 8);
-
-                for (unsigned i = 16; i > 0; i--) {
-                        unsigned j = i - 1;
-                        unsigned d = 0;
-
-                        if (j <= start_byte) {
-                                int16_t t;
-
-                                d = delta & 0xFF;
-                                delta >>= 8;
-
-                                t = u->in6.s6_addr[j] + d + overflow;
-                                overflow = t > UINT8_MAX ? t - UINT8_MAX : 0;
-
-                                result.s6_addr[j] = (uint8_t)t;
-                        } else
-                                result.s6_addr[j] = u->in6.s6_addr[j];
-                }
-
-                if (overflow || delta != 0)
                         return -ERANGE;
 
-                u->in6 = result;
+                for (unsigned i = 16; i > 0; i--) {
-                return 1;
+                        unsigned t, j = i - 1, p = j * 8;
+
+                        if (p >= prefixlen) {
+                                u->in6.s6_addr[j] = 0;
+                                continue;
+                        }
+
+                        if (prefixlen - p < 8) {
+                                u->in6.s6_addr[j] &= 0xff << (8 - (prefixlen - p));
+                                t = u->in6.s6_addr[j] + ((nth & 0xff) << (8 - (prefixlen - p)));
+                                nth >>= prefixlen - p;
+                        } else {
+                                t = u->in6.s6_addr[j] + (nth & 0xff) + overflow;
+                                nth >>= 8;
+                        }
+
+                        overflow = t > UINT8_MAX;
+                        u->in6.s6_addr[j] = (uint8_t) (t & 0xff);
+                }
+
+                if (overflow || nth != 0)
+                        return -ERANGE;
+
+                return 0;
         }
 
         return -EAFNOSUPPORT;
@@ -358,6 +350,43 @@ int in_addr_random_prefix(
         return -EAFNOSUPPORT;
 }
 
+int in_addr_prefix_range(
+                int family,
+                const union in_addr_union *in,
+                unsigned prefixlen,
+                union in_addr_union *ret_start,
+                union in_addr_union *ret_end) {
+
+        union in_addr_union start, end;
+        int r;
+
+        assert(in);
+
+        if (!IN_SET(family, AF_INET, AF_INET6))
+                return -EAFNOSUPPORT;
+
+        if (ret_start) {
+                start = *in;
+                r = in_addr_prefix_nth(family, &start, prefixlen, 0);
+                if (r < 0)
+                        return r;
+        }
+
+        if (ret_end) {
+                end = *in;
+                r = in_addr_prefix_nth(family, &end, prefixlen, 1);
+                if (r < 0)
+                        return r;
+        }
+
+        if (ret_start)
+                *ret_start = start;
+        if (ret_end)
+                *ret_end = end;
+
+        return 0;
+}
+
 int in_addr_to_string(int family, const union in_addr_union *u, char **ret) {
         _cleanup_free_ char *x = NULL;
         size_t l;

src/basic/in-addr-util.h

@@ -41,6 +41,12 @@ int in_addr_prefix_intersect(int family, const union in_addr_union *a, unsigned
 int in_addr_prefix_next(int family, union in_addr_union *u, unsigned prefixlen);
 int in_addr_prefix_nth(int family, union in_addr_union *u, unsigned prefixlen, uint64_t nth);
 int in_addr_random_prefix(int family, union in_addr_union *u, unsigned prefixlen_fixed_part, unsigned prefixlen);
+int in_addr_prefix_range(
+                int family,
+                const union in_addr_union *in,
+                unsigned prefixlen,
+                union in_addr_union *ret_start,
+                union in_addr_union *ret_end);
 int in_addr_to_string(int family, const union in_addr_union *u, char **ret);
 int in_addr_prefix_to_string(int family, const union in_addr_union *u, unsigned prefixlen, char **ret);
 int in_addr_port_ifindex_name_to_string(int family, const union in_addr_union *u, uint16_t port, int ifindex, const char *server_name, char **ret);

src/shared/firewall-util-nft.c

@@ -18,7 +18,6 @@
 #include "firewall-util-private.h"
 #include "in-addr-util.h"
 #include "macro.h"
-#include "memory-util.h"
 #include "socket-util.h"
 #include "time-util.h"
 
@@ -30,9 +29,6 @@
 
 #define UDP_DPORT_OFFSET 2
 
-void nft_in6addr_to_range(const union in_addr_union *source, unsigned int prefixlen,
-                          struct in6_addr *start, struct in6_addr *end);
-
 static int nfnl_netlink_sendv(sd_netlink *nfnl,
                               sd_netlink_message *messages[],
                               size_t msgcount) {
@@ -848,55 +844,19 @@ static int fw_nftables_recreate_table(sd_netlink *nfnl, int af, sd_netlink_messa
         return 0;
 }
 
-void nft_in6addr_to_range(const union in_addr_union *source, unsigned int prefixlen,
+static int nft_message_add_setelem_ip6range(
-                          struct in6_addr *ret_start, struct in6_addr *ret_end) {
+                sd_netlink_message *m,
-        uint8_t carry = 0;
-        int i, j;
-
-        assert(prefixlen <= 128);
-
-        for (i = 0, j = 15; i < 16; i++) {
-                uint8_t nm;
-
-                nm = 0xFF;
-                if (prefixlen < 8)
-                        nm = 0xFF << (8 - prefixlen);
-
-                ret_start->s6_addr[i] = source->in6.s6_addr[i] & nm;
-                if (prefixlen <= 8 && j == 15) {
-                         carry = 1u << (8 - prefixlen);
-                         j = i;
-                }
-
-                if (prefixlen >= 8)
-                         prefixlen -= 8;
-                else
-                         prefixlen = 0;
-        }
-        *ret_end = *ret_start;
-
-        for (; j >= 0; j--) {
-                uint16_t overflow = ret_end->s6_addr[j] + carry;
-
-                ret_end->s6_addr[j] = overflow;
-                if (overflow <= 0xff)
-                        break;
-                carry = 1;
-        }
-
-        if (memcmp(ret_start, ret_end, sizeof(*ret_start)) > 0)
-                zero(ret_end);
-}
-
-static int nft_message_add_setelem_ip6range(sd_netlink_message *m,
                 const union in_addr_union *source,
                 unsigned int prefixlen) {
-        struct in6_addr start, end;
+
+        union in_addr_union start, end;
         int r;
 
-        nft_in6addr_to_range(source, prefixlen, &start, &end);
+        r = in_addr_prefix_range(AF_INET6, source, prefixlen, &start, &end);
+        if (r < 0)
+                return r;
 
-        r = sd_nfnl_nft_message_add_setelem(m, 0, &start, sizeof(start), NULL, 0);
+        r = sd_nfnl_nft_message_add_setelem(m, 0, &start.in6, sizeof(start.in6), NULL, 0);
         if (r < 0)
                 return r;
 
@@ -904,7 +864,7 @@ static int nft_message_add_setelem_ip6range(sd_netlink_message *m,
         if (r < 0)
                 return r;
 
-        r = sd_nfnl_nft_message_add_setelem(m, 1, &end, sizeof(end), NULL, 0);
+        r = sd_nfnl_nft_message_add_setelem(m, 1, &end.in6, sizeof(end.in6), NULL, 0);
         if (r < 0)
                 return r;
 

src/test/test-firewall-util.c

@@ -1,6 +1,4 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
-#include <arpa/inet.h>
-#include <stdlib.h>
 
 #include "firewall-util.h"
 #include "log.h"
@@ -8,32 +6,14 @@
 #include "tests.h"
 
 #define MAKE_IN_ADDR_UNION(a,b,c,d) (union in_addr_union) { .in.s_addr = htobe32((uint32_t) (a) << 24 | (uint32_t) (b) << 16 | (uint32_t) (c) << 8 | (uint32_t) (d))}
-
+#define MAKE_IN6_ADDR_UNION(str, u) assert_se(in_addr_from_string(AF_INET6, str, u) >= 0)
-void nft_in6addr_to_range(const union in_addr_union *source, unsigned int prefixlen,
-                          struct in6_addr *start, struct in6_addr *end);
-
-static void make_in6_addr_union(const char *addr, union in_addr_union *u) {
-        assert_se(inet_pton(AF_INET6, addr, &u->in6) >= 0);
-}
-
-static bool test_in6_eq(const char *addr, const union in_addr_union *u) {
-        union in_addr_union tmp;
-
-        make_in6_addr_union(addr, &tmp);
-
-        return memcmp(&tmp.in6, &u->in6, sizeof(tmp.in6)) == 0;
-}
-
-static void assert_in6_eq(const union in_addr_union *a, const union in_addr_union *b) {
-        assert_se(memcmp(&a->in6, &b->in6, sizeof(a->in6)) == 0);
-}
 
 static void test_v6(FirewallContext **ctx) {
         union in_addr_union u = {}, u2 = {};
         uint8_t prefixlen;
         int r;
 
-        make_in6_addr_union("dead::beef", &u);
+        MAKE_IN6_ADDR_UNION("dead::beef", &u);
 
         r = fw_add_masquerade(ctx, true, AF_INET6, &u, 128);
         if (r < 0)
@@ -55,7 +35,7 @@ static void test_v6(FirewallContext **ctx) {
         if (r < 0)
                 log_error_errno(r, "Failed to modify firewall: %m");
 
-        make_in6_addr_union("1c3::c01d", &u2);
+        MAKE_IN6_ADDR_UNION("1c3::c01d", &u2);
         r = fw_add_local_dnat(ctx, true, AF_INET6, IPPROTO_TCP, 4711, &u2, 815, &u);
         if (r < 0)
                 log_error_errno(r, "Failed to modify firewall: %m");
@@ -77,52 +57,6 @@ static void test_v6(FirewallContext **ctx) {
                 log_error_errno(r, "Failed to modify ipv6 firewall: %m");
 }
 
-static void test_v6_range(void) {
-        unsigned int prefixlen = 64;
-        union in_addr_union a, b, s;
-
-        make_in6_addr_union("dead:0:0:beef::", &s);
-
-        nft_in6addr_to_range(&s, prefixlen, &a.in6, &b.in6);
-
-        assert_in6_eq(&s, &a);
-        assert_se(test_in6_eq("dead:0:0:bef0::", &b));
-
-        make_in6_addr_union("2001::", &s);
-        prefixlen = 56;
-        nft_in6addr_to_range(&s, prefixlen, &a.in6, &b.in6);
-        assert_in6_eq(&s, &a);
-        assert_se(test_in6_eq("2001:0:0:0100::", &b));
-
-        prefixlen = 48;
-        nft_in6addr_to_range(&s, prefixlen, &a.in6, &b.in6);
-        assert_in6_eq(&s, &a);
-
-        assert_se(test_in6_eq("2001:0:0001::", &b));
-
-        prefixlen = 65;
-        nft_in6addr_to_range(&s, prefixlen, &a.in6, &b.in6);
-        assert_se(test_in6_eq("2001::", &a));
-
-        assert_se(test_in6_eq("2001::8000:0:0:0", &b));
-
-        prefixlen = 66;
-        nft_in6addr_to_range(&s, prefixlen, &a.in6, &b.in6);
-        assert_in6_eq(&s, &a);
-
-        assert_se(test_in6_eq("2001::4000:0:0:0", &b));
-
-        prefixlen = 127;
-        nft_in6addr_to_range(&s, prefixlen, &a.in6, &b.in6);
-        assert_in6_eq(&s, &a);
-        assert_se(test_in6_eq("2001::0002", &b));
-
-        make_in6_addr_union("dead:beef::1", &s);
-        prefixlen = 64;
-        nft_in6addr_to_range(&s, prefixlen, &a.in6, &b.in6);
-        assert_se(test_in6_eq("dead:beef::", &a));
-}
-
 int main(int argc, char *argv[]) {
         _cleanup_(fw_ctx_freep) FirewallContext *ctx;
         int r;
@@ -175,7 +109,6 @@ int main(int argc, char *argv[]) {
                 log_error_errno(r, "Failed to modify firewall: %m");
 
         test_v6(&ctx);
-        test_v6_range();
 
         return 0;
 }

src/test/test-in-addr-util.c

@@ -238,10 +238,12 @@ static void test_in_addr_prefix_intersect(void) {
 static void test_in_addr_prefix_next_one(unsigned f, const char *before, unsigned pl, const char *after) {
         union in_addr_union ubefore, uafter, t;
 
+        log_info("/* %s(%s, prefixlen=%u) */", __func__, before, pl);
+
         assert_se(in_addr_from_string(f, before, &ubefore) >= 0);
 
         t = ubefore;
-        assert_se((in_addr_prefix_next(f, &t, pl) > 0) == !!after);
+        assert_se((in_addr_prefix_next(f, &t, pl) >= 0) == !!after);
 
         if (after) {
                 assert_se(in_addr_from_string(f, after, &uafter) >= 0);
@@ -250,13 +252,12 @@ static void test_in_addr_prefix_next_one(unsigned f, const char *before, unsigne
 }
 
 static void test_in_addr_prefix_next(void) {
-        log_info("/* %s */", __func__);
-
         test_in_addr_prefix_next_one(AF_INET, "192.168.0.0", 24, "192.168.1.0");
         test_in_addr_prefix_next_one(AF_INET, "192.168.0.0", 16, "192.169.0.0");
         test_in_addr_prefix_next_one(AF_INET, "192.168.0.0", 20, "192.168.16.0");
 
         test_in_addr_prefix_next_one(AF_INET, "0.0.0.0", 32, "0.0.0.1");
+        test_in_addr_prefix_next_one(AF_INET, "255.255.255.254", 32, "255.255.255.255");
         test_in_addr_prefix_next_one(AF_INET, "255.255.255.255", 32, NULL);
         test_in_addr_prefix_next_one(AF_INET, "255.255.255.0", 24, NULL);
 
@@ -275,10 +276,12 @@ static void test_in_addr_prefix_next(void) {
 static void test_in_addr_prefix_nth_one(unsigned f, const char *before, unsigned pl, uint64_t nth, const char *after) {
         union in_addr_union ubefore, uafter, t;
 
+        log_info("/* %s(%s, prefixlen=%u, nth=%"PRIu64") */", __func__, before, pl, nth);
+
         assert_se(in_addr_from_string(f, before, &ubefore) >= 0);
 
         t = ubefore;
-        assert_se((in_addr_prefix_nth(f, &t, pl, nth) > 0) == !!after);
+        assert_se((in_addr_prefix_nth(f, &t, pl, nth) >= 0) == !!after);
 
         if (after) {
                 assert_se(in_addr_from_string(f, after, &uafter) >= 0);
@@ -287,10 +290,9 @@ static void test_in_addr_prefix_nth_one(unsigned f, const char *before, unsigned
 }
 
 static void test_in_addr_prefix_nth(void) {
-        log_info("/* %s */", __func__);
-
         test_in_addr_prefix_nth_one(AF_INET, "192.168.0.0", 24, 0, "192.168.0.0");
-        test_in_addr_prefix_nth_one(AF_INET, "192.168.0.0", 24, 1, "192.168.1.0");
+        test_in_addr_prefix_nth_one(AF_INET, "192.168.0.123", 24, 0, "192.168.0.0");
+        test_in_addr_prefix_nth_one(AF_INET, "192.168.0.123", 24, 1, "192.168.1.0");
         test_in_addr_prefix_nth_one(AF_INET, "192.168.0.0", 24, 4, "192.168.4.0");
         test_in_addr_prefix_nth_one(AF_INET, "192.168.0.0", 25, 1, "192.168.0.128");
         test_in_addr_prefix_nth_one(AF_INET, "192.168.255.0", 25, 1, "192.168.255.128");
@@ -309,6 +311,48 @@ static void test_in_addr_prefix_nth(void) {
         test_in_addr_prefix_nth_one(AF_INET6, "0000::", 8, 256, NULL);
         test_in_addr_prefix_nth_one(AF_INET6, "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", 128, 1, NULL);
         test_in_addr_prefix_nth_one(AF_INET6, "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", 0, 1, NULL);
+        test_in_addr_prefix_nth_one(AF_INET6, "1234:5678:90ab:cdef:1234:5678:90ab:cdef", 12, 1, "1240::");
+}
+
+static void test_in_addr_prefix_range_one(
+                int family,
+                const char *in,
+                unsigned prefixlen,
+                const char *expected_start,
+                const char *expected_end) {
+
+        union in_addr_union a, s, e;
+
+        log_info("/* %s(%s, prefixlen=%u) */", __func__, in, prefixlen);
+
+        assert_se(in_addr_from_string(family, in, &a) >= 0);
+        assert_se((in_addr_prefix_range(family, &a, prefixlen, &s, &e) >= 0) == !!expected_start);
+
+        if (expected_start) {
+                union in_addr_union es;
+
+                assert_se(in_addr_from_string(family, expected_start, &es) >= 0);
+                assert_se(in_addr_equal(family, &s, &es) > 0);
+        }
+        if (expected_end) {
+                union in_addr_union ee;
+
+                assert_se(in_addr_from_string(family, expected_end, &ee) >= 0);
+                assert_se(in_addr_equal(family, &e, &ee) > 0);
+        }
+}
+
+static void test_in_addr_prefix_range(void) {
+        test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 24, "192.168.123.0", "192.168.124.0");
+        test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 16, "192.168.0.0", "192.169.0.0");
+
+        test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 64, "dead:beef::", "dead:beef:0:1::");
+        test_in_addr_prefix_range_one(AF_INET6, "dead:0:0:beef::", 64, "dead:0:0:beef::", "dead:0:0:bef0::");
+        test_in_addr_prefix_range_one(AF_INET6, "2001::",  48, "2001::", "2001:0:1::");
+        test_in_addr_prefix_range_one(AF_INET6, "2001::",  56, "2001::", "2001:0:0:0100::");
+        test_in_addr_prefix_range_one(AF_INET6, "2001::",  65, "2001::", "2001::8000:0:0:0");
+        test_in_addr_prefix_range_one(AF_INET6, "2001::",  66, "2001::", "2001::4000:0:0:0");
+        test_in_addr_prefix_range_one(AF_INET6, "2001::", 127, "2001::", "2001::2");
 }
 
 static void test_in_addr_to_string_one(int f, const char *addr) {
@@ -339,6 +383,7 @@ int main(int argc, char *argv[]) {
         test_in_addr_prefix_intersect();
         test_in_addr_prefix_next();
         test_in_addr_prefix_nth();
+        test_in_addr_prefix_range();
         test_in_addr_to_string();
 
         return 0;