#include <sys/ioctl.h>
#include <netinet/if_ether.h>
+#include "siphash24.h"
+
#include "sd-dhcp-server.h"
#include "dhcp-server-internal.h"
#include "dhcp-internal.h"
-#define DHCP_DEFAULT_LEASE_TIME 60
+#define DHCP_DEFAULT_LEASE_TIME 3600 /* one hour */
int sd_dhcp_server_set_lease_pool(sd_dhcp_server *server, struct in_addr *address,
size_t size) {
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);
+
+ server->bound_leases = new0(DHCPLease*, size);
+ if (!server->bound_leases)
+ return -ENOMEM;
server->pool_start = address->s_addr;
server->pool_size = size;
return 0;
}
+bool sd_dhcp_server_is_running(sd_dhcp_server *server) {
+ assert_return(server, -EINVAL);
+
+ return !!server->receive_message;
+}
+
sd_dhcp_server *sd_dhcp_server_ref(sd_dhcp_server *server) {
if (server)
assert_se(REFCNT_INC(server->n_ref) >= 2);
return server;
}
+unsigned long client_id_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
+ uint64_t u;
+ const DHCPClientId *id = p;
+
+ assert(id);
+ assert(id->length);
+ assert(id->data);
+
+ siphash24((uint8_t*) &u, id->data, id->length, hash_key);
+
+ return (unsigned long) u;
+}
+
+int client_id_compare_func(const void *_a, const void *_b) {
+ const DHCPClientId *a, *b;
+
+ a = _a;
+ b = _b;
+
+ assert(!a->length || a->data);
+ assert(!b->length || b->data);
+
+ if (a->length != b->length)
+ return a->length < b->length ? -1 : 1;
+
+ return memcmp(a->data, b->data, a->length);
+}
+
+static void dhcp_lease_free(DHCPLease *lease) {
+ if (!lease)
+ return;
+
+ free(lease->client_id.data);
+ free(lease);
+}
+
sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) {
- if (server && REFCNT_DEC(server->n_ref) <= 0) {
- log_dhcp_server(server, "UNREF");
+ DHCPLease *lease;
- sd_dhcp_server_stop(server);
+ if (!server)
+ return NULL;
- sd_event_unref(server->event);
- free(server);
- }
+ if (REFCNT_DEC(server->n_ref) > 0)
+ return NULL;
+
+ log_dhcp_server(server, "UNREF");
+
+ sd_dhcp_server_stop(server);
+
+ sd_event_unref(server->event);
+
+ while ((lease = hashmap_steal_first(server->leases_by_client_id)))
+ dhcp_lease_free(lease);
+ hashmap_free(server->leases_by_client_id);
+
+ free(server->bound_leases);
+ free(server);
return NULL;
}
server->fd = -1;
server->address = htobe32(INADDR_ANY);
server->index = ifindex;
+ server->leases_by_client_id = hashmap_new(client_id_hash_func, client_id_compare_func);
*ret = server;
server = NULL;
} else if (req->message->ciaddr && type != DHCP_NAK)
destination = req->message->ciaddr;
- if (destination || requested_broadcast(req) || type == DHCP_NAK)
+ if (destination != INADDR_ANY)
return dhcp_server_send_udp(server, destination, &packet->dhcp,
sizeof(DHCPMessage) + optoffset);
+ else if (requested_broadcast(req) || type == DHCP_NAK)
+ return dhcp_server_send_udp(server, INADDR_BROADCAST, &packet->dhcp,
+ sizeof(DHCPMessage) + optoffset);
else
/* we cannot send UDP packet to specific MAC address when the address is
not yet configured, so must fall back to raw packets */
assert(server);
assert(ret);
assert(_optoffset);
- assert(IN_SET(type, DHCP_OFFER, DHCP_ACK));
+ assert(IN_SET(type, DHCP_OFFER, DHCP_ACK, DHCP_NAK));
packet = malloc0(sizeof(DHCPPacket) + req->max_optlen);
if (!packet)
packet->dhcp.yiaddr = address;
- /* for one minute */
- lease_time = htobe32(DHCP_DEFAULT_LEASE_TIME);
+ lease_time = htobe32(req->lifetime);
r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, &lease_time);
if (r < 0)
packet->dhcp.yiaddr = address;
- /* for ten seconds */
- lease_time = htobe32(DHCP_DEFAULT_LEASE_TIME);
+ lease_time = htobe32(req->lifetime);
r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, &lease_time);
if (r < 0)
return 0;
}
+static int server_send_nak(sd_dhcp_server *server, DHCPRequest *req) {
+ _cleanup_free_ DHCPPacket *packet = NULL;
+ size_t offset;
+ int r;
+
+ r = server_message_init(server, &packet, DHCP_NAK, &offset, req);
+ if (r < 0)
+ return r;
+
+ r = dhcp_server_send_packet(server, req, packet, DHCP_NAK, offset);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
static int parse_request(uint8_t code, uint8_t len, const uint8_t *option,
void *user_data) {
DHCPRequest *req = user_data;
assert(req);
switch(code) {
+ case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
+ if (len == 4)
+ req->lifetime = be32toh(*(be32_t*)option);
+
+ break;
case DHCP_OPTION_REQUESTED_IP_ADDRESS:
if (len == 4)
req->requested_ip = *(be32_t*)option;
if (req->max_optlen < DHCP_MIN_OPTIONS_SIZE)
req->max_optlen = DHCP_MIN_OPTIONS_SIZE;
+ if (!req->lifetime)
+ req->lifetime = DHCP_DEFAULT_LEASE_TIME;
+
return 0;
}
+static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) {
+ assert(server);
+
+ 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;
+
+ return be32toh(requested_ip) - be32toh(server->pool_start);
+}
+
int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
size_t length) {
_cleanup_dhcp_request_free_ DHCPRequest *req = NULL;
+ DHCPLease *existing_lease;
int type, r;
assert(server);
/* this only fails on critical errors */
return r;
+ existing_lease = hashmap_get(server->leases_by_client_id, &req->client_id);
+
switch(type) {
case DHCP_DISCOVER:
{
- be32_t address;
+ be32_t address = INADDR_ANY;
+ unsigned i;
log_dhcp_server(server, "DISCOVER (0x%x)",
be32toh(req->message->xid));
/* no pool allocated */
return 0;
- /* for now pick a random address from the pool */
- address = htobe32(be32toh(server->pool_start) +
- (random_u32() % server->pool_size));
+ /* for now pick a random free address from the pool */
+ if (existing_lease)
+ address = existing_lease->address;
+ else {
+ for (i = 0; i < server->pool_size; i++) {
+ if (!server->bound_leases[server->next_offer]) {
+ address = htobe32(be32toh(server->pool_start) + server->next_offer);
+ break;
+ } else
+ server->next_offer = (server->next_offer + 1) % server->pool_size;
+ }
+ }
+
+ if (address == INADDR_ANY)
+ /* no free addresses left */
+ return 0;
r = server_send_offer(server, req, address);
if (r < 0) {
break;
}
+ case DHCP_DECLINE:
+ log_dhcp_server(server, "DECLINE (0x%x)",
+ be32toh(req->message->xid));
+
+ /* TODO: make sure we don't offer this address again */
+
+ return 1;
+
+ break;
case DHCP_REQUEST:
{
be32_t address;
+ bool init_reboot = false;
+ int pool_offset;
/* see RFC 2131, section 4.3.2 */
/* this MUST be zero */
return 0;
- /* TODO: check if requested IP is correct, NAK if not */
+ /* TODO: check more carefully if IP is correct */
address = req->requested_ip;
+ init_reboot = true;
} else {
log_dhcp_server(server, "REQUEST (rebinding/renewing) (0x%x)",
be32toh(req->message->xid));
address = req->message->ciaddr;
}
- /* for now we just verify that the address is from the pool, not
- whether or not it is taken */
- if (htobe32(req->requested_ip) >= htobe32(server->pool_start) &&
- htobe32(req->requested_ip) < htobe32(server->pool_start) +
- + server->pool_size) {
+ pool_offset = get_pool_offset(server, address);
+
+ /* verify that the requested address is from the pool, and either
+ owned by the current client or free */
+ if (pool_offset >= 0 &&
+ server->bound_leases[pool_offset] == existing_lease) {
+ DHCPLease *lease;
+ usec_t time_now;
+
+ if (!existing_lease) {
+ lease = new0(DHCPLease, 1);
+ lease->address = req->requested_ip;
+ lease->client_id.data = memdup(req->client_id.data,
+ req->client_id.length);
+ if (!lease->client_id.data) {
+ free(lease);
+ return -ENOMEM;
+ }
+ lease->client_id.length = req->client_id.length;
+ } else
+ lease = existing_lease;
+
+ r = sd_event_now(server->event, CLOCK_MONOTONIC, &time_now);
+ if (r < 0)
+ time_now = now(CLOCK_MONOTONIC);
+ lease->expiration = req->lifetime * USEC_PER_SEC + time_now;
+
r = server_send_ack(server, req, address);
if (r < 0) {
/* this only fails on critical errors */
log_dhcp_server(server, "could not send ack: %s",
strerror(-r));
+
+ if (!existing_lease)
+ dhcp_lease_free(lease);
+
return r;
} else {
log_dhcp_server(server, "ACK (0x%x)",
be32toh(req->message->xid));
+
+ server->bound_leases[pool_offset] = lease;
+ hashmap_put(server->leases_by_client_id, &lease->client_id, lease);
+
return DHCP_ACK;
}
- } else
- return 0;
+ } else if (init_reboot) {
+ r = server_send_nak(server, req);
+ if (r < 0) {
+ /* this only fails on critical errors */
+ log_dhcp_server(server, "could not send nak: %s",
+ strerror(-r));
+ return r;
+ } else {
+ log_dhcp_server(server, "NAK (0x%x)",
+ be32toh(req->message->xid));
+ return DHCP_NAK;
+ }
+ }
break;
}
+ case DHCP_RELEASE: {
+ int pool_offset;
+
+ log_dhcp_server(server, "RELEASE (0x%x)",
+ be32toh(req->message->xid));
+
+ if (!existing_lease)
+ return 0;
+
+ if (existing_lease->address != req->message->ciaddr)
+ return 0;
+
+ pool_offset = get_pool_offset(server, req->message->ciaddr);
+ if (pool_offset < 0)
+ return 0;
+
+ if (server->bound_leases[pool_offset] == existing_lease) {
+ server->bound_leases[pool_offset] = NULL;
+ hashmap_remove(server->leases_by_client_id, existing_lease);
+ dhcp_lease_free(existing_lease);
+
+ return 1;
+ } else
+ return 0;
+ }
}
return 0;
~ianmdlvl / elogind.git / blobdiff