network: several cleanups and fixes for DHCPv4 client

src/basic/in-addr-util.c

@@ -727,17 +727,21 @@ int in_addr_mask(int family, union in_addr_union *addr, unsigned char prefixlen)
         }
 }
 
-int in4_addr_prefix_covers(
+int in4_addr_prefix_covers_full(
                 const struct in_addr *prefix,
                 unsigned char prefixlen,
-                const struct in_addr *address) {
+                const struct in_addr *address,
+                unsigned char address_prefixlen) {
 
         struct in_addr masked_prefix, masked_address;
         int r;
 
         assert(prefix);
         assert(address);
 
+        if (prefixlen > address_prefixlen)
+                return false;
+
         masked_prefix = *prefix;
         r = in4_addr_mask(&masked_prefix, prefixlen);
         if (r < 0)
@@ -751,17 +755,21 @@ int in4_addr_prefix_covers(
         return in4_addr_equal(&masked_prefix, &masked_address);
 }
 
-int in6_addr_prefix_covers(
+int in6_addr_prefix_covers_full(
                 const struct in6_addr *prefix,
                 unsigned char prefixlen,
-                const struct in6_addr *address) {
+                const struct in6_addr *address,
+                unsigned char address_prefixlen) {
 
         struct in6_addr masked_prefix, masked_address;
         int r;
 
         assert(prefix);
         assert(address);
 
+        if (prefixlen > address_prefixlen)
+                return false;
+
         masked_prefix = *prefix;
         r = in6_addr_mask(&masked_prefix, prefixlen);
         if (r < 0)
@@ -775,20 +783,21 @@ int in6_addr_prefix_covers(
         return in6_addr_equal(&masked_prefix, &masked_address);
 }
 
-int in_addr_prefix_covers(
+int in_addr_prefix_covers_full(
                 int family,
                 const union in_addr_union *prefix,
                 unsigned char prefixlen,
-                const union in_addr_union *address) {
+                const union in_addr_union *address,
+                unsigned char address_prefixlen) {
 
         assert(prefix);
         assert(address);
 
         switch (family) {
         case AF_INET:
-                return in4_addr_prefix_covers(&prefix->in, prefixlen, &address->in);
+                return in4_addr_prefix_covers_full(&prefix->in, prefixlen, &address->in, address_prefixlen);
         case AF_INET6:
-                return in6_addr_prefix_covers(&prefix->in6, prefixlen, &address->in6);
+                return in6_addr_prefix_covers_full(&prefix->in6, prefixlen, &address->in6, address_prefixlen);
         default:
                 return -EAFNOSUPPORT;
         }

src/basic/in-addr-util.h

@@ -144,9 +144,18 @@ int in4_addr_default_subnet_mask(const struct in_addr *addr, struct in_addr *mas
 int in4_addr_mask(struct in_addr *addr, unsigned char prefixlen);
 int in6_addr_mask(struct in6_addr *addr, unsigned char prefixlen);
 int in_addr_mask(int family, union in_addr_union *addr, unsigned char prefixlen);
-int in4_addr_prefix_covers(const struct in_addr *prefix, unsigned char prefixlen, const struct in_addr *address);
-int in6_addr_prefix_covers(const struct in6_addr *prefix, unsigned char prefixlen, const struct in6_addr *address);
-int in_addr_prefix_covers(int family, const union in_addr_union *prefix, unsigned char prefixlen, const union in_addr_union *address);
+int in4_addr_prefix_covers_full(const struct in_addr *prefix, unsigned char prefixlen, const struct in_addr *address, unsigned char address_prefixlen);
+int in6_addr_prefix_covers_full(const struct in6_addr *prefix, unsigned char prefixlen, const struct in6_addr *address, unsigned char address_prefixlen);
+int in_addr_prefix_covers_full(int family, const union in_addr_union *prefix, unsigned char prefixlen, const union in_addr_union *address, unsigned char address_prefixlen);
+static inline int in4_addr_prefix_covers(const struct in_addr *prefix, unsigned char prefixlen, const struct in_addr *address) {
+        return in4_addr_prefix_covers_full(prefix, prefixlen, address, 32);
+}
+static inline int in6_addr_prefix_covers(const struct in6_addr *prefix, unsigned char prefixlen, const struct in6_addr *address) {
+        return in6_addr_prefix_covers_full(prefix, prefixlen, address, 128);
+}
+static inline int in_addr_prefix_covers(int family, const union in_addr_union *prefix, unsigned char prefixlen, const union in_addr_union *address) {
+        return in_addr_prefix_covers_full(family, prefix, prefixlen, address, family == AF_INET ? 32 : family == AF_INET6 ? 128 : 0);
+}
 int in_addr_parse_prefixlen(int family, const char *p, unsigned char *ret);
 int in_addr_prefix_from_string(const char *p, int family, union in_addr_union *ret_prefix, unsigned char *ret_prefixlen);
 

src/libsystemd-network/sd-dhcp-lease.c

@@ -201,6 +201,34 @@ int sd_dhcp_lease_get_netmask(sd_dhcp_lease *lease, struct in_addr *addr) {
         return 0;
 }
 
+int sd_dhcp_lease_get_prefix(sd_dhcp_lease *lease, struct in_addr *ret_prefix, uint8_t *ret_prefixlen) {
+        struct in_addr address, netmask;
+        uint8_t prefixlen;
+        int r;
+
+        assert_return(lease, -EINVAL);
+
+        r = sd_dhcp_lease_get_address(lease, &address);
+        if (r < 0)
+                return r;
+
+        r = sd_dhcp_lease_get_netmask(lease, &netmask);
+        if (r < 0)
+                return r;
+
+        prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
+
+        r = in4_addr_mask(&address, prefixlen);
+        if (r < 0)
+                return r;
+
+        if (ret_prefix)
+                *ret_prefix = address;
+        if (ret_prefixlen)
+                *ret_prefixlen = prefixlen;
+        return 0;
+}
+
 int sd_dhcp_lease_get_server_identifier(sd_dhcp_lease *lease, struct in_addr *addr) {
         assert_return(lease, -EINVAL);
         assert_return(addr, -EINVAL);