#include <errno.h>
#include <string.h>
#include <stdio.h>
+#include <net/ethernet.h>
#include "util.h"
#include "list.h"
#include "dhcp-protocol.h"
+#include "dhcp-internal.h"
#include "sd-dhcp-client.h"
+#define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
+
struct sd_dhcp_client {
DHCPState state;
+ sd_event *event;
+ sd_event_source *timeout_resend;
int index;
uint8_t *req_opts;
size_t req_opts_size;
uint32_t last_addr;
+ struct ether_addr mac_addr;
+ uint32_t xid;
+ usec_t start_time;
};
static const uint8_t default_req_opts[] = {
return 0;
}
-sd_dhcp_client *sd_dhcp_client_new(void)
+int sd_dhcp_client_set_mac(sd_dhcp_client *client,
+ const struct ether_addr *addr)
+{
+ assert_return(client, -EINVAL);
+ assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
+
+ memcpy(&client->mac_addr, addr, ETH_ALEN);
+
+ return 0;
+}
+
+static int client_stop(sd_dhcp_client *client, int error)
+{
+ assert_return(client, -EINVAL);
+ assert_return(client->state != DHCP_STATE_INIT &&
+ client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
+
+ client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+
+ switch (client->state) {
+
+ case DHCP_STATE_INIT:
+ case DHCP_STATE_SELECTING:
+
+ client->state = DHCP_STATE_INIT;
+ break;
+
+ case DHCP_STATE_INIT_REBOOT:
+ case DHCP_STATE_REBOOTING:
+ case DHCP_STATE_REQUESTING:
+ case DHCP_STATE_BOUND:
+ case DHCP_STATE_RENEWING:
+ case DHCP_STATE_REBINDING:
+
+ break;
+ }
+
+ return 0;
+}
+
+static int client_packet_init(sd_dhcp_client *client, uint8_t type,
+ DHCPMessage *message, uint16_t secs,
+ uint8_t **opt, size_t *optlen)
+{
+ int err;
+
+ *opt = (uint8_t *)(message + 1);
+
+ if (*optlen < 4)
+ return -ENOBUFS;
+ *optlen -= 4;
+
+ message->op = BOOTREQUEST;
+ message->htype = 1;
+ message->hlen = ETHER_ADDR_LEN;
+ message->xid = htobe32(client->xid);
+
+ /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
+ refuse to issue an DHCP lease if 'secs' is set to zero */
+ message->secs = htobe16(secs);
+
+ memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
+ (*opt)[0] = 0x63;
+ (*opt)[1] = 0x82;
+ (*opt)[2] = 0x53;
+ (*opt)[3] = 0x63;
+
+ *opt += 4;
+
+ err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
+ &type);
+ if (err < 0)
+ return err;
+
+ /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
+ Identifier option is not set */
+ err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
+ ETH_ALEN, &client->mac_addr);
+ if (err < 0)
+ return err;
+
+ if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
+ err = dhcp_option_append(opt, optlen,
+ DHCP_OPTION_PARAMETER_REQUEST_LIST,
+ client->req_opts_size,
+ client->req_opts);
+ if (err < 0)
+ return err;
+ }
+
+ return 0;
+}
+
+static uint16_t client_checksum(void *buf, int len)
+{
+ uint32_t sum;
+ uint16_t *check;
+ int i;
+ uint8_t *odd;
+
+ sum = 0;
+ check = buf;
+
+ for (i = 0; i < len / 2 ; i++)
+ sum += check[i];
+
+ if (len & 0x01) {
+ odd = buf;
+ sum += odd[len];
+ }
+
+ return ~((sum & 0xffff) + (sum >> 16));
+}
+
+static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
+{
+ int err = 0;
+ _cleanup_free_ DHCPPacket *discover;
+ size_t optlen, len;
+ uint8_t *opt;
+
+ optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
+ len = sizeof(DHCPPacket) + optlen;
+
+ discover = malloc0(len);
+
+ if (!discover)
+ return -ENOMEM;
+
+ err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
+ secs, &opt, &optlen);
+ if (err < 0)
+ return err;
+
+ if (client->last_addr != INADDR_ANY) {
+ err = dhcp_option_append(&opt, &optlen,
+ DHCP_OPTION_REQUESTED_IP_ADDRESS,
+ 4, &client->last_addr);
+ if (err < 0)
+ return err;
+ }
+
+ err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
+ if (err < 0)
+ return err;
+
+ discover->ip.version = IPVERSION;
+ discover->ip.ihl = sizeof(discover->ip) >> 2;
+ discover->ip.tot_len = htobe16(len);
+
+ discover->ip.protocol = IPPROTO_UDP;
+ discover->ip.saddr = INADDR_ANY;
+ discover->ip.daddr = INADDR_BROADCAST;
+
+ discover->udp.source = htobe16(DHCP_PORT_CLIENT);
+ discover->udp.dest = htobe16(DHCP_PORT_SERVER);
+ discover->udp.len = htobe16(len - sizeof(discover->ip));
+
+ discover->ip.check = discover->udp.len;
+ discover->udp.check = client_checksum(&discover->ip.ttl,
+ len - 8);
+
+ discover->ip.ttl = IPDEFTTL;
+ discover->ip.check = 0;
+ discover->ip.check = client_checksum(&discover->ip,
+ sizeof(discover->ip));
+
+ err = dhcp_network_send_raw_packet(client->index, discover, len);
+
+ return 0;
+}
+
+static int client_timeout_resend(sd_event_source *s, uint64_t usec,
+ void *userdata)
+{
+ sd_dhcp_client *client = userdata;
+ usec_t next_timeout;
+ uint16_t secs;
+ int err = 0;
+
+ switch (client->state) {
+ case DHCP_STATE_INIT:
+ case DHCP_STATE_SELECTING:
+
+ if (!client->start_time)
+ client->start_time = usec;
+
+ secs = (usec - client->start_time) / USEC_PER_SEC;
+
+ next_timeout = usec + 2 * USEC_PER_SEC + (random() & 0x1fffff);
+
+ err = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_resend, client,
+ &client->timeout_resend);
+ if (err < 0)
+ goto error;
+
+ if (client_send_discover(client, secs) >= 0)
+ client->state = DHCP_STATE_SELECTING;
+
+ break;
+
+ case DHCP_STATE_INIT_REBOOT:
+ case DHCP_STATE_REBOOTING:
+ case DHCP_STATE_REQUESTING:
+ case DHCP_STATE_BOUND:
+ case DHCP_STATE_RENEWING:
+ case DHCP_STATE_REBINDING:
+
+ break;
+ }
+
+ return 0;
+
+error:
+ client_stop(client, err);
+
+ /* Errors were dealt with when stopping the client, don't spill
+ errors into the event loop handler */
+ return 0;
+}
+
+int sd_dhcp_client_start(sd_dhcp_client *client)
+{
+ int err;
+
+ assert_return(client, -EINVAL);
+ assert_return(client->index >= 0, -EINVAL);
+ assert_return(client->state == DHCP_STATE_INIT ||
+ client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
+
+ client->xid = random_u();
+
+ err = sd_event_add_monotonic(client->event, now(CLOCK_MONOTONIC), 0,
+ client_timeout_resend, client,
+ &client->timeout_resend);
+ if (err < 0)
+ goto error;
+
+ return 0;
+
+error:
+ client_stop(client, err);
+
+ return err;
+}
+
+int sd_dhcp_client_stop(sd_dhcp_client *client)
+{
+ return client_stop(client, 0);
+}
+
+sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
{
sd_dhcp_client *client;
+ assert_return(event, NULL);
+
client = new0(sd_dhcp_client, 1);
if (!client)
return NULL;
+ client->event = sd_event_ref(event);
client->state = DHCP_STATE_INIT;
client->index = -1;
~ianmdlvl / elogind.git / blobdiff