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-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;
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-12-12 17:52:21 +0000