networkd: add a number of calls to manipulate in_addr_union structs

2 files changed, 194 insertions, 0 deletions

diff --git a/src/shared/socket-util.c b/src/shared/socket-util.c
index 92564e3193..f8c6795e7c 100644
--- a/src/shared/socket-util.c
+++ b/src/shared/socket-util.c
@@ -640,6 +640,193 @@ int socket_address_unlink(SocketAddress *a) {
         return 1;
 }
 
+int in_addr_null(unsigned family, union in_addr_union *u) {
+        assert(u);
+
+        if (family == AF_INET)
+                return u->in.s_addr == 0;
+
+        if (family == AF_INET6)
+                return
+                        u->in6.s6_addr32[0] == 0 &&
+                        u->in6.s6_addr32[1] == 0 &&
+                        u->in6.s6_addr32[2] == 0 &&
+                        u->in6.s6_addr32[3] == 0;
+
+        return -EAFNOSUPPORT;
+}
+
+
+int in_addr_equal(unsigned family, union in_addr_union *a, union in_addr_union *b) {
+        assert(a);
+        assert(b);
+
+        if (family == AF_INET)
+                return a->in.s_addr == b->in.s_addr;
+
+        if (family == AF_INET6)
+                return
+                        a->in6.s6_addr32[0] == b->in6.s6_addr32[0] &&
+                        a->in6.s6_addr32[1] == b->in6.s6_addr32[1] &&
+                        a->in6.s6_addr32[2] == b->in6.s6_addr32[2] &&
+                        a->in6.s6_addr32[3] == b->in6.s6_addr32[3];
+
+        return -EAFNOSUPPORT;
+}
+
+int in_addr_prefix_intersect(
+                unsigned family,
+                const union in_addr_union *a,
+                unsigned aprefixlen,
+                const union in_addr_union *b,
+                unsigned bprefixlen) {
+
+        unsigned m;
+
+        assert(a);
+        assert(b);
+
+        /* Checks whether there are any addresses that are in both
+         * networks */
+
+        m = MIN(aprefixlen, bprefixlen);
+
+        if (family == AF_INET) {
+                uint32_t x, nm;
+
+                x = be32toh(a->in.s_addr ^ b->in.s_addr);
+                nm = 0xFFFFFFFFUL << (32 - m);
+
+                return (x & nm) == 0;
+        }
+
+        if (family == AF_INET6) {
+                unsigned i;
+
+                if (m > 128)
+                        m = 128;
+
+                for (i = 0; i < 16; i++) {
+                        uint8_t x, nm;
+
+                        x = a->in6.s6_addr[i] ^ b->in6.s6_addr[i];
+
+                        if (m < 8)
+                                nm = 0xFF << (8 - m);
+                        else
+                                nm = 0xFF;
+
+                        if ((x & nm) != 0)
+                                return 0;
+
+                        if (m > 8)
+                                m -= 8;
+                        else
+                                m = 0;
+                }
+
+                return 1;
+        }
+
+        return -EAFNOSUPPORT;
+}
+
+int in_addr_prefix_next(unsigned family, union in_addr_union *u, unsigned prefixlen) {
+        assert(u);
+
+        /* Increases the network part of an address by one. Returns
+         * positive it that succeeds, or 0 if this overflows. */
+
+        if (prefixlen <= 0)
+                return 0;
+
+        if (family == AF_INET) {
+                uint32_t c, n;
+
+                if (prefixlen > 32)
+                        prefixlen = 32;
+
+                c = be32toh(u->in.s_addr);
+                n = c + (1UL << (32 - prefixlen));
+                if (n < c)
+                        return 0;
+                n &= 0xFFFFFFFFUL << (32 - prefixlen);
+
+                u->in.s_addr = htobe32(n);
+                return 1;
+        }
+
+        if (family == AF_INET6) {
+                struct in6_addr add = {}, result;
+                uint8_t overflow = 0;
+                unsigned i;
+
+                if (prefixlen > 128)
+                        prefixlen = 128;
+
+                /* First calculate what we have to add */
+                add.s6_addr[(prefixlen-1) / 8] = 1 << (7 - (prefixlen-1) % 8);
+
+                for (i = 16; i > 0; i--) {
+                        unsigned j = i - 1;
+
+                        result.s6_addr[j] = u->in6.s6_addr[j] + add.s6_addr[j] + overflow;
+                        overflow = (result.s6_addr[j] < u->in6.s6_addr[j]);
+                }
+
+                if (overflow)
+                        return 0;
+
+                u->in6 = result;
+                return 1;
+        }
+
+        return -EAFNOSUPPORT;
+}
+
+int in_addr_to_string(unsigned family, const union in_addr_union *u, char **ret) {
+        char *x;
+        size_t l;
+
+        assert(u);
+        assert(ret);
+
+        if (family == AF_INET)
+                l = INET_ADDRSTRLEN;
+        else if (family == AF_INET6)
+                l = INET6_ADDRSTRLEN;
+        else
+                return -EAFNOSUPPORT;
+
+        x = new(char, l);
+        if (!x)
+                return -ENOMEM;
+
+        errno = 0;
+        if (!inet_ntop(family, u, x, l)) {
+                free(x);
+                return errno ? -errno : -EINVAL;
+        }
+
+        *ret = x;
+        return 0;
+}
+
+int in_addr_from_string(unsigned family, const char *s, union in_addr_union *ret) {
+
+        assert(s);
+        assert(ret);
+
+        if (!IN_SET(family, AF_INET, AF_INET6))
+                return -EAFNOSUPPORT;
+
+        errno = 0;
+        if (inet_pton(family, s, ret) <= 0)
+                return errno ? -errno : -EINVAL;
+
+        return 0;
+}
+
 static const char* const netlink_family_table[] = {
         [NETLINK_ROUTE] = "route",
         [NETLINK_FIREWALL] = "firewall",
diff --git a/src/shared/socket-util.h b/src/shared/socket-util.h
index d125fca83f..25c4a7e4f9 100644
--- a/src/shared/socket-util.h
+++ b/src/shared/socket-util.h
@@ -111,3 +111,10 @@ SocketAddressBindIPv6Only socket_address_bind_ipv6_only_from_string(const char *
 
 int netlink_family_to_string_alloc(int b, char **s);
 int netlink_family_from_string(const char *s) _pure_;
+
+int in_addr_null(unsigned family, union in_addr_union *u);
+int in_addr_equal(unsigned family, union in_addr_union *a, union in_addr_union *b);
+int in_addr_prefix_intersect(unsigned family, const union in_addr_union *a, unsigned aprefixlen, const union in_addr_union *b, unsigned bprefixlen);
+int in_addr_prefix_next(unsigned family, union in_addr_union *u, unsigned prefixlen);
+int in_addr_to_string(unsigned family, const union in_addr_union *u, char **ret);
+int in_addr_from_string(unsigned family, const char *s, union in_addr_union *ret);