***/
#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"
-int sd_dhcp_server_set_address(sd_dhcp_server *server, struct in_addr *address) {
+#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(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);
+
+ server->bound_leases = new0(DHCPLease*, size);
+ if (!server->bound_leases)
+ return -ENOMEM;
+
+ server->pool_start = address->s_addr;
+ 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));
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 const struct hash_ops client_id_hash_ops = {
+ .hash = client_id_hash_func,
+ .compare = client_id_compare_func
+};
+
+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_raw = -1;
server->fd = -1;
server->address = htobe32(INADDR_ANY);
+ server->netmask = htobe32(INADDR_ANY);
server->index = ifindex;
+ server->leases_by_client_id = hashmap_new(&client_id_hash_ops);
*ret = server;
server = NULL;
return 0;
}
-int sd_dhcp_server_attach_event(sd_dhcp_server *server, sd_event *event, int priority) {
+int sd_dhcp_server_attach_event(sd_dhcp_server *server, sd_event *event,
+ int priority) {
int r;
assert_return(server, -EINVAL);
return 0;
}
-static int dhcp_server_send_unicast_raw(sd_dhcp_server *server, DHCPPacket *packet,
- size_t len) {
+static int dhcp_server_send_unicast_raw(sd_dhcp_server *server,
+ DHCPPacket *packet, size_t len) {
union sockaddr_union link = {
.ll.sll_family = AF_PACKET,
.ll.sll_protocol = htons(ETH_P_IP),
memcpy(&link.ll.sll_addr, &packet->dhcp.chaddr, ETH_ALEN);
dhcp_packet_append_ip_headers(packet, server->address, DHCP_PORT_SERVER,
- packet->dhcp.yiaddr, DHCP_PORT_CLIENT, len);
+ packet->dhcp.yiaddr,
+ DHCP_PORT_CLIENT, len);
r = dhcp_network_send_raw_socket(server->fd_raw, &link, packet, len);
if (r < 0)
} 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 */
+ /* we cannot send UDP packet to specific MAC address when the
+ address is not yet configured, so must fall back to raw
+ packets */
return dhcp_server_send_unicast_raw(server, packet,
sizeof(DHCPPacket) + optoffset);
}
+static int server_message_init(sd_dhcp_server *server, DHCPPacket **ret,
+ uint8_t type, size_t *_optoffset,
+ DHCPRequest *req) {
+ _cleanup_free_ DHCPPacket *packet = NULL;
+ size_t optoffset = 0;
+ int r;
+
+ assert(server);
+ assert(ret);
+ assert(_optoffset);
+ assert(IN_SET(type, DHCP_OFFER, DHCP_ACK, DHCP_NAK));
+
+ packet = malloc0(sizeof(DHCPPacket) + req->max_optlen);
+ if (!packet)
+ return -ENOMEM;
+
+ r = dhcp_message_init(&packet->dhcp, BOOTREPLY,
+ be32toh(req->message->xid), type, ARPHRD_ETHER,
+ req->max_optlen, &optoffset);
+ if (r < 0)
+ return r;
+
+ packet->dhcp.flags = req->message->flags;
+ packet->dhcp.giaddr = req->message->giaddr;
+ memcpy(&packet->dhcp.chaddr, &req->message->chaddr, ETH_ALEN);
+
+ *_optoffset = optoffset;
+ *ret = packet;
+ packet = NULL;
+
+ return 0;
+}
+
+static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req,
+ be32_t address) {
+ _cleanup_free_ DHCPPacket *packet = NULL;
+ size_t offset;
+ be32_t lease_time;
+ int r;
+
+ r = server_message_init(server, &packet, DHCP_OFFER, &offset, req);
+ if (r < 0)
+ return r;
+
+ packet->dhcp.yiaddr = address;
+
+ 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 r;
+
+ r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+ DHCP_OPTION_SUBNET_MASK, 4, &server->netmask);
+ if (r < 0)
+ return r;
+
+ r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+ DHCP_OPTION_ROUTER, 4, &server->address);
+ if (r < 0)
+ return r;
+
+ r = dhcp_server_send_packet(server, req, packet, DHCP_OFFER, offset);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int server_send_ack(sd_dhcp_server *server, DHCPRequest *req,
+ be32_t address) {
+ _cleanup_free_ DHCPPacket *packet = NULL;
+ size_t offset;
+ be32_t lease_time;
+ int r;
+
+ r = server_message_init(server, &packet, DHCP_ACK, &offset, req);
+ if (r < 0)
+ return r;
+
+ packet->dhcp.yiaddr = address;
+
+ 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 r;
+
+ r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+ DHCP_OPTION_SUBNET_MASK, 4, &server->netmask);
+ if (r < 0)
+ return r;
+
+ r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+ DHCP_OPTION_ROUTER, 4, &server->address);
+ if (r < 0)
+ return r;
+
+ r = dhcp_server_send_packet(server, req, packet, DHCP_ACK, offset);
+ if (r < 0)
+ return r;
+
+ 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 server_send_forcerenew(sd_dhcp_server *server, be32_t address,
+ be32_t gateway, uint8_t chaddr[]) {
+ _cleanup_free_ DHCPPacket *packet = NULL;
+ size_t optoffset = 0;
+ int r;
+
+ assert(server);
+ assert(address != INADDR_ANY);
+ assert(chaddr);
+
+ packet = malloc0(sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE);
+ if (!packet)
+ return -ENOMEM;
+
+ r = dhcp_message_init(&packet->dhcp, BOOTREPLY, 0,
+ DHCP_FORCERENEW, ARPHRD_ETHER,
+ DHCP_MIN_OPTIONS_SIZE, &optoffset);
+ if (r < 0)
+ return r;
+
+ r = dhcp_option_append(&packet->dhcp, DHCP_MIN_OPTIONS_SIZE,
+ &optoffset, 0, DHCP_OPTION_END, 0, NULL);
+ if (r < 0)
+ return r;
+
+ memcpy(&packet->dhcp.chaddr, chaddr, ETH_ALEN);
+
+ r = dhcp_server_send_udp(server, address, &packet->dhcp,
+ sizeof(DHCPMessage) + optoffset);
+ 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;
+
+ break;
case DHCP_OPTION_SERVER_IDENTIFIER:
if (len == 4)
req->server_id = *(be32_t*)option;
req->message = message;
- /* set client id based on mac address if client did not send an explicit one */
+ /* set client id based on MAC address if client did not send an explicit
+ one */
if (!req->client_id.data) {
uint8_t *data;
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;
- log_dhcp_server(server, "received message of type %d", type);
+ existing_lease = hashmap_get(server->leases_by_client_id,
+ &req->client_id);
+
+ switch(type) {
+ case DHCP_DISCOVER:
+ {
+ be32_t address = INADDR_ANY;
+ unsigned i;
+
+ log_dhcp_server(server, "DISCOVER (0x%x)",
+ be32toh(req->message->xid));
+
+ if (!server->pool_size)
+ /* no pool allocated */
+ return 0;
+
+ /* 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) {
+ /* this only fails on critical errors */
+ log_dhcp_server(server, "could not send offer: %s",
+ strerror(-r));
+ return r;
+ } else {
+ log_dhcp_server(server, "OFFER (0x%x)",
+ be32toh(req->message->xid));
+ return DHCP_OFFER;
+ }
+
+ 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 */
+
+ if (req->server_id) {
+ log_dhcp_server(server, "REQUEST (selecting) (0x%x)",
+ be32toh(req->message->xid));
+
+ /* SELECTING */
+ if (req->server_id != server->address)
+ /* client did not pick us */
+ return 0;
+
+ if (req->message->ciaddr)
+ /* this MUST be zero */
+ return 0;
+
+ if (!req->requested_ip)
+ /* this must be filled in with the yiaddr
+ from the chosen OFFER */
+ return 0;
+
+ address = req->requested_ip;
+ } else if (req->requested_ip) {
+ log_dhcp_server(server, "REQUEST (init-reboot) (0x%x)",
+ be32toh(req->message->xid));
+
+ /* INIT-REBOOT */
+ if (req->message->ciaddr)
+ /* this MUST be zero */
+ return 0;
+
+ /* 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));
+
+ /* REBINDING / RENEWING */
+ if (!req->message->ciaddr)
+ /* this MUST be filled in with clients IP address */
+ return 0;
+
+ address = req->message->ciaddr;
+ }
+
+ 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 = 0;
+
+ 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;
+ memcpy(&lease->chaddr, &req->message->chaddr,
+ ETH_ALEN);
+ lease->gateway = req->message->giaddr;
+ } else
+ lease = existing_lease;
+
+ r = sd_event_now(server->event,
+ clock_boottime_or_monotonic(),
+ &time_now);
+ if (r < 0)
+ time_now = now(clock_boottime_or_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 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 1;
+ return 0;
}
static int server_receive_message(sd_event_source *s, int fd,
cmsg->cmsg_len == CMSG_LEN(sizeof(struct in_pktinfo))) {
struct in_pktinfo *info = (struct in_pktinfo*)CMSG_DATA(cmsg);
- /* TODO figure out if this can be done as a filter on the socket, like for IPv6 */
+ /* TODO figure out if this can be done as a filter on
+ * the socket, like for IPv6 */
if (server->index != info->ipi_ifindex)
return 0;
return 0;
}
+
+int sd_dhcp_server_forcerenew(sd_dhcp_server *server) {
+ unsigned i;
+ int r = 0;
+
+ assert_return(server, -EINVAL);
+ assert(server->bound_leases);
+
+ for (i = 0; i < server->pool_size; i++) {
+ DHCPLease *lease = server->bound_leases[i];
+
+ if (!lease)
+ continue;
+
+ r = server_send_forcerenew(server, lease->address,
+ lease->gateway,
+ lease->chaddr);
+ if (r < 0)
+ return r;
+ else
+ log_dhcp_server(server, "FORCERENEW");
+ }
+
+ return r;
+}