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authorTom Gundersen <teg@jklm.no>2015-08-28 20:29:10 +0200
committerTom Gundersen <teg@jklm.no>2015-08-31 21:34:58 +0200
commit99634696183dfabae20104e58157c69029a11594 (patch)
treebaa3505182666eaf47944ce6b1d4c0fd93ce28a7 /src/libsystemd-network
parentd728d7faa6c60f185be72510d87bcc565bc0846a (diff)
sd-dhcp-server: simplify pool creation
Merge sd_dhcp_server_set_address() and sd_dhcp_server_set_lease_pool() into sd_dhcp_server_configure_pool() as the behavior of the two former depends on the order they are called in. The flexibility is not needed, so let's just do this in one call.
Diffstat (limited to 'src/libsystemd-network')
-rw-r--r--src/libsystemd-network/dhcp-server-internal.h6
-rw-r--r--src/libsystemd-network/sd-dhcp-server.c85
-rw-r--r--src/libsystemd-network/test-dhcp-server.c27
3 files changed, 75 insertions, 43 deletions
diff --git a/src/libsystemd-network/dhcp-server-internal.h b/src/libsystemd-network/dhcp-server-internal.h
index 268210fc50..5dc3c7aa26 100644
--- a/src/libsystemd-network/dhcp-server-internal.h
+++ b/src/libsystemd-network/dhcp-server-internal.h
@@ -57,8 +57,9 @@ struct sd_dhcp_server {
int ifindex;
be32_t address;
be32_t netmask;
- be32_t pool_start;
- size_t pool_size;
+ be32_t subnet;
+ uint32_t pool_offset;
+ uint32_t pool_size;
char *timezone;
@@ -67,6 +68,7 @@ struct sd_dhcp_server {
Hashmap *leases_by_client_id;
DHCPLease **bound_leases;
+ DHCPLease invalid_lease;
uint32_t max_lease_time, default_lease_time;
};
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
index 89b9a4c6be..7a8b298b51 100644
--- a/src/libsystemd-network/sd-dhcp-server.c
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -22,6 +22,7 @@
#include <sys/ioctl.h>
+#include "in-addr-util.h"
#include "siphash24.h"
#include "sd-dhcp-server.h"
@@ -31,38 +32,63 @@
#define DHCP_DEFAULT_LEASE_TIME_USEC USEC_PER_HOUR
#define DHCP_MAX_LEASE_TIME_USEC (USEC_PER_HOUR*12)
-int sd_dhcp_server_set_lease_pool(sd_dhcp_server *server,
- struct in_addr *address,
- size_t size) {
+/* configures the server's address and subnet, and optionally the pool's size and offset into the subnet
+ * the whole pool must fit into the subnet, and may not contain the first (any) nor last (broadcast) address
+ * moreover, the server's own address may be in the pool, and is in that case reserved in order not to
+ * accidentally hand it out */
+int sd_dhcp_server_configure_pool(sd_dhcp_server *server, struct in_addr *address, unsigned char prefixlen, uint32_t offset, uint32_t size) {
+ struct in_addr netmask_addr;
+ be32_t netmask;
+ uint32_t server_off, broadcast_off, size_max;
+
assert_return(server, -EINVAL);
assert_return(address, -EINVAL);
- assert_return(address->s_addr, -EINVAL);
- assert_return(size, -EINVAL);
- assert_return(server->pool_start == htobe32(INADDR_ANY), -EBUSY);
- assert_return(!server->pool_size, -EBUSY);
- assert_return(!server->bound_leases, -EBUSY);
+ assert_return(address->s_addr != INADDR_ANY, -EINVAL);
+ assert_return(prefixlen <= 32, -ERANGE);
+ assert_return(server->address == INADDR_ANY, -EBUSY);
+
+ assert_se(in_addr_prefixlen_to_netmask(&netmask_addr, prefixlen));
+ netmask = netmask_addr.s_addr;
+
+ server_off = be32toh(address->s_addr & ~netmask);
+ broadcast_off = be32toh(~netmask);
+
+ /* the server address cannot be the subnet address */
+ assert_return(server_off != 0, -ERANGE);
+
+ /* nor the broadcast address */
+ assert_return(server_off != broadcast_off, -ERANGE);
+
+ /* 0 offset means we should set a default, we skip the first (subnet) address
+ and take the next one */
+ if (offset == 0)
+ offset = 1;
+
+ size_max = (broadcast_off + 1) /* the number of addresses in the subnet */
+ - offset /* exclude the addresses before the offset */
+ - 1; /* exclude the last (broadcast) address */
+
+ /* The pool must contain at least one address */
+ assert_return(size_max >= 1, -ERANGE);
+
+ if (size != 0)
+ assert_return(size <= size_max, -ERANGE);
+ else
+ size = size_max;
server->bound_leases = new0(DHCPLease*, size);
if (!server->bound_leases)
return -ENOMEM;
- server->pool_start = address->s_addr;
+ server->pool_offset = offset;
server->pool_size = size;
- return 0;
-}
-
-int sd_dhcp_server_set_address(sd_dhcp_server *server, struct in_addr *address,
- unsigned char prefixlen) {
- assert_return(server, -EINVAL);
- assert_return(address, -EINVAL);
- assert_return(address->s_addr, -EINVAL);
- assert_return(prefixlen <= 32, -ERANGE);
- assert_return(server->address == htobe32(INADDR_ANY), -EBUSY);
- assert_return(server->netmask == htobe32(INADDR_ANY), -EBUSY);
-
server->address = address->s_addr;
- server->netmask = htobe32(0xfffffffflu << (32 - prefixlen));
+ server->netmask = netmask;
+ server->subnet = address->s_addr & netmask;
+
+ if (server_off >= offset && server_off - offset < size)
+ server->bound_leases[server_off - offset] = &server->invalid_lease;
return 0;
}
@@ -661,12 +687,11 @@ static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) {
if (!server->pool_size)
return -EINVAL;
- if (be32toh(requested_ip) < be32toh(server->pool_start) ||
- be32toh(requested_ip) >= be32toh(server->pool_start) +
- + server->pool_size)
- return -EINVAL;
+ if (be32toh(requested_ip) < (be32toh(server->subnet) | server->pool_offset) ||
+ be32toh(requested_ip) >= (be32toh(server->subnet) | (server->pool_offset + server->pool_size)))
+ return -ERANGE;
- return be32toh(requested_ip) - be32toh(server->pool_start);
+ return be32toh(requested_ip & ~server->netmask) - server->pool_offset;
}
#define HASH_KEY SD_ID128_MAKE(0d,1d,fe,bd,f1,24,bd,b3,47,f1,dd,6e,73,21,93,30)
@@ -718,7 +743,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
if (existing_lease)
address = existing_lease->address;
else {
- size_t next_offer;
+ uint32_t next_offer;
/* even with no persistence of leases, we try to offer the same client
the same IP address. we do this by using the hash of the client id
@@ -728,7 +753,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
for (i = 0; i < server->pool_size; i++) {
if (!server->bound_leases[next_offer]) {
- address = htobe32(be32toh(server->pool_start) + next_offer);
+ address = server->subnet | htobe32(server->pool_offset + next_offer);
break;
} else
next_offer = (next_offer + 1) % server->pool_size;
@@ -1022,7 +1047,7 @@ int sd_dhcp_server_forcerenew(sd_dhcp_server *server) {
for (i = 0; i < server->pool_size; i++) {
DHCPLease *lease = server->bound_leases[i];
- if (!lease)
+ if (!lease || lease == &server->invalid_lease)
continue;
r = server_send_forcerenew(server, lease->address,
diff --git a/src/libsystemd-network/test-dhcp-server.c b/src/libsystemd-network/test-dhcp-server.c
index 9f60ab761e..7d8a1f6bd9 100644
--- a/src/libsystemd-network/test-dhcp-server.c
+++ b/src/libsystemd-network/test-dhcp-server.c
@@ -28,6 +28,14 @@
#include "sd-dhcp-server.h"
#include "dhcp-server-internal.h"
+static void test_pool(struct in_addr *address, unsigned size, int ret) {
+ _cleanup_dhcp_server_unref_ sd_dhcp_server *server = NULL;
+
+ assert_se(sd_dhcp_server_new(&server, 1) >= 0);
+
+ assert_se(sd_dhcp_server_configure_pool(server, address, 8, 0, size) == ret);
+}
+
static int test_basic(sd_event *event) {
_cleanup_dhcp_server_unref_ sd_dhcp_server *server = NULL;
struct in_addr address_lo = {
@@ -54,15 +62,14 @@ static int test_basic(sd_event *event) {
assert_se(!sd_dhcp_server_unref(server));
assert_se(sd_dhcp_server_start(server) == -EUNATCH);
- assert_se(sd_dhcp_server_set_address(server, &address_any, 28) == -EINVAL);
- assert_se(sd_dhcp_server_set_address(server, &address_lo, 38) == -ERANGE);
- assert_se(sd_dhcp_server_set_address(server, &address_lo, 8) >= 0);
- assert_se(sd_dhcp_server_set_address(server, &address_lo, 8) == -EBUSY);
- assert_se(sd_dhcp_server_set_lease_pool(server, &address_any, 1) == -EINVAL);
- assert_se(sd_dhcp_server_set_lease_pool(server, &address_lo, 0) == -EINVAL);
- assert_se(sd_dhcp_server_set_lease_pool(server, &address_lo, 1) >= 0);
- assert_se(sd_dhcp_server_set_lease_pool(server, &address_lo, 1) == -EBUSY);
+ assert_se(sd_dhcp_server_configure_pool(server, &address_any, 28, 0, 0) == -EINVAL);
+ assert_se(sd_dhcp_server_configure_pool(server, &address_lo, 38, 0, 0) == -ERANGE);
+ assert_se(sd_dhcp_server_configure_pool(server, &address_lo, 8, 0, 0) >= 0);
+ assert_se(sd_dhcp_server_configure_pool(server, &address_lo, 8, 0, 0) == -EBUSY);
+
+ test_pool(&address_any, 1, -EINVAL);
+ test_pool(&address_lo, 1, 0);
r = sd_dhcp_server_start(server);
@@ -119,12 +126,10 @@ static void test_message_handler(void) {
};
assert_se(sd_dhcp_server_new(&server, 1) >= 0);
- assert_se(sd_dhcp_server_set_address(server, &address_lo, 8) >= 0);
+ assert_se(sd_dhcp_server_configure_pool(server, &address_lo, 8, 0, 0) >= 0);
assert_se(sd_dhcp_server_attach_event(server, NULL, 0) >= 0);
assert_se(sd_dhcp_server_start(server) >= 0);
- assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
- assert_se(sd_dhcp_server_set_lease_pool(server, &address_lo, 10) >= 0);
assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
test.end = 0;