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authorTom Gundersen <teg@jklm.no>2014-10-27 17:38:03 +0100
committerTom Gundersen <teg@jklm.no>2014-10-27 17:40:24 +0100
commitdf40eee8edccb6bf09a57c2b96f69d233032ce52 (patch)
tree3b2c4fbf001cba0b9a5ea0bb6b152899525c25bd
parent1dfcee5985e8097fdbe0a77ca31fa23f683fadc2 (diff)
shared: in-addr-utils - add default_subnet_mask and default_prefixlen methods
These use the (deprecated) IPv4 address classes to deduce the corresponding subnet masks. This is useful when addresses without subnet masks and prefix lengths are given. Make use of these new functions from sd-dhcp-lease.
-rw-r--r--src/libsystemd-network/sd-dhcp-lease.c24
-rw-r--r--src/shared/in-addr-util.c43
-rw-r--r--src/shared/in-addr-util.h2
3 files changed, 54 insertions, 15 deletions
diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
index 6680d06736..4fb01c0729 100644
--- a/src/libsystemd-network/sd-dhcp-lease.c
+++ b/src/libsystemd-network/sd-dhcp-lease.c
@@ -30,6 +30,7 @@
#include "list.h"
#include "mkdir.h"
#include "fileio.h"
+#include "in-addr-util.h"
#include "dhcp-protocol.h"
#include "dhcp-internal.h"
@@ -803,27 +804,20 @@ int dhcp_lease_load(const char *lease_file, sd_dhcp_lease **ret) {
}
int dhcp_lease_set_default_subnet_mask(sd_dhcp_lease *lease) {
- uint32_t address;
+ struct in_addr address;
+ struct in_addr mask;
+ int r;
assert(lease);
- assert(lease->address != INADDR_ANY);
- address = be32toh(lease->address);
+ address.s_addr = lease->address;
/* fall back to the default subnet masks based on address class */
+ r = in_addr_default_subnet_mask(&address, &mask);
+ if (r < 0)
+ return r;
- if ((address >> 31) == 0x0)
- /* class A, leading bits: 0 */
- lease->subnet_mask = htobe32(0xff000000);
- else if ((address >> 30) == 0x2)
- /* class B, leading bits 10 */
- lease->subnet_mask = htobe32(0xffff0000);
- else if ((address >> 29) == 0x6)
- /* class C, leading bits 110 */
- lease->subnet_mask = htobe32(0xffffff00);
- else
- /* class D or E, no default mask. give up */
- return -ERANGE;
+ lease->subnet_mask = mask.s_addr;
return 0;
}
diff --git a/src/shared/in-addr-util.c b/src/shared/in-addr-util.c
index 457eedd6d8..5fbee6caf2 100644
--- a/src/shared/in-addr-util.c
+++ b/src/shared/in-addr-util.c
@@ -248,3 +248,46 @@ unsigned in_addr_netmask_to_prefixlen(const struct in_addr *addr) {
return 32 - u32ctz(be32toh(addr->s_addr));
}
+
+int in_addr_default_prefixlen(const struct in_addr *addr, unsigned char *prefixlen) {
+ uint32_t address;
+
+ assert(addr);
+ assert(addr->s_addr != INADDR_ANY);
+ assert(prefixlen);
+
+ address = be32toh(addr->s_addr);
+
+ if ((address >> 31) == 0x0)
+ /* class A, leading bits: 0 */
+ *prefixlen = 8;
+ else if ((address >> 30) == 0x2)
+ /* class B, leading bits 10 */
+ *prefixlen = 16;
+ else if ((address >> 29) == 0x6)
+ /* class C, leading bits 110 */
+ *prefixlen = 24;
+ else
+ /* class D or E, no default prefixlen */
+ return -ERANGE;
+
+ return 0;
+}
+
+int in_addr_default_subnet_mask(const struct in_addr *addr, struct in_addr *mask) {
+ unsigned char prefixlen;
+ int r;
+
+ assert(addr);
+ assert(mask);
+
+ r = in_addr_default_prefixlen(addr, &prefixlen);
+ if (r < 0)
+ return r;
+
+ assert(prefixlen > 0 && prefixlen < 32);
+
+ mask->s_addr = htobe32((0xffffffff << (32 - prefixlen)) & 0xffffffff);
+
+ return 0;
+}
diff --git a/src/shared/in-addr-util.h b/src/shared/in-addr-util.h
index 0036acee22..8da030ceb6 100644
--- a/src/shared/in-addr-util.h
+++ b/src/shared/in-addr-util.h
@@ -40,6 +40,8 @@ int in_addr_to_string(int family, const union in_addr_union *u, char **ret);
int in_addr_from_string(int family, const char *s, union in_addr_union *ret);
int in_addr_from_string_auto(const char *s, int *family, union in_addr_union *ret);
unsigned in_addr_netmask_to_prefixlen(const struct in_addr *addr);
+int in_addr_default_prefixlen(const struct in_addr *addr, unsigned char *prefixlen);
+int in_addr_default_subnet_mask(const struct in_addr *addr, struct in_addr *mask);
static inline size_t FAMILY_ADDRESS_SIZE(int family) {
assert(family == AF_INET || family == AF_INET6);