#define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
+struct DHCPLease {
+ uint32_t lifetime;
+ uint32_t address;
+ uint32_t server_address;
+ uint32_t subnet_mask;
+ uint32_t router;
+};
+
+typedef struct DHCPLease DHCPLease;
+
struct sd_dhcp_client {
DHCPState state;
+ sd_event *event;
+ sd_event_source *timeout_resend;
int index;
+ int fd;
+ union sockaddr_union link;
+ sd_event_source *receive_message;
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;
+ DHCPLease *lease;
};
static const uint8_t default_req_opts[] = {
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->receive_message =
+ sd_event_source_unref(client->receive_message);
+
+ if (client->fd >= 0)
+ close(client->fd);
+ client->fd = -1;
+
+ client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+
+ switch (client->state) {
+
+ case DHCP_STATE_INIT:
+ case DHCP_STATE_SELECTING:
+
+ client->start_time = 0;
+ 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;
+ }
+
+ if (client->lease) {
+ free(client->lease);
+ client->lease = NULL;
+ }
+
+ return 0;
+}
+
static int client_packet_init(sd_dhcp_client *client, uint8_t type,
- DHCPMessage *message, uint8_t **opt,
- size_t *optlen)
+ DHCPMessage *message, uint16_t secs,
+ uint8_t **opt, size_t *optlen)
{
int err;
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;
return ~((sum & 0xffff) + (sum >> 16));
}
-static int client_send_discover(sd_dhcp_client *client)
+static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
{
int err = 0;
_cleanup_free_ DHCPPacket *discover;
return -ENOMEM;
err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
- &opt, &optlen);
+ secs, &opt, &optlen);
if (err < 0)
return err;
discover->ip.check = client_checksum(&discover->ip,
sizeof(discover->ip));
- err = dhcp_network_send_raw_packet(client->index, discover, len);
+ err = dhcp_network_send_raw_socket(client->fd, &client->link,
+ discover, len);
+
+ return err;
+}
+
+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;
+}
+
+static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
+ void *user_data)
+{
+ DHCPLease *lease = user_data;
+ be32_t val;
+
+ switch(code) {
+
+ case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
+ if (len == 4) {
+ memcpy(&val, option, 4);
+ lease->lifetime = be32toh(val);
+ }
+
+ break;
+
+ case DHCP_OPTION_SERVER_IDENTIFIER:
+ if (len >= 4)
+ memcpy(&lease->server_address, option, 4);
+
+ break;
+
+ case DHCP_OPTION_SUBNET_MASK:
+ if (len >= 4)
+ memcpy(&lease->subnet_mask, option, 4);
+
+ break;
+
+ case DHCP_OPTION_ROUTER:
+ if (len >= 4)
+ memcpy(&lease->router, option, 4);
+
+ break;
+ }
return 0;
}
+static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
+ size_t len)
+{
+ size_t hdrlen;
+ DHCPLease *lease;
+
+ if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
+ return -EINVAL;
+
+ hdrlen = offer->ip.ihl * 4;
+ if (hdrlen < 20 || hdrlen > len || client_checksum(&offer->ip,
+ hdrlen))
+ return -EINVAL;
+
+ offer->ip.check = offer->udp.len;
+ offer->ip.ttl = 0;
+
+ if (hdrlen + be16toh(offer->udp.len) > len ||
+ client_checksum(&offer->ip.ttl, be16toh(offer->udp.len) + 12))
+ return -EINVAL;
+
+ if (be16toh(offer->udp.source) != DHCP_PORT_SERVER ||
+ be16toh(offer->udp.dest) != DHCP_PORT_CLIENT)
+ return -EINVAL;
+
+ if (offer->dhcp.op != BOOTREPLY)
+ return -EINVAL;
+
+ if (be32toh(offer->dhcp.xid) != client->xid)
+ return -EINVAL;
+
+ if (memcmp(&offer->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
+ ETHER_ADDR_LEN))
+ return -EINVAL;
+
+ lease = new0(DHCPLease, 1);
+ if (!lease)
+ return -ENOMEM;
+
+ len = len - DHCP_IP_UDP_SIZE;
+ if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
+ lease) != DHCP_OFFER)
+ goto error;
+
+ lease->address = offer->dhcp.yiaddr;
+
+ if (lease->address == INADDR_ANY ||
+ lease->server_address == INADDR_ANY ||
+ lease->subnet_mask == INADDR_ANY ||
+ lease->lifetime == 0)
+ goto error;
+
+ client->lease = lease;
+
+ return 0;
+
+error:
+ free(lease);
+
+ return -ENOMSG;
+}
+
+static int client_receive_raw_message(sd_event_source *s, int fd,
+ uint32_t revents, void *userdata)
+{
+ sd_dhcp_client *client = userdata;
+ uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
+ int buflen = sizeof(buf);
+ int len;
+ DHCPPacket *message;
+
+ len = read(fd, &buf, buflen);
+ if (len < 0)
+ goto error;
+
+ message = (DHCPPacket *)&buf;
+
+ switch (client->state) {
+ case DHCP_STATE_SELECTING:
+
+ if (client_receive_offer(client, message, len) >= 0) {
+
+ client->receive_message =
+ sd_event_source_unref(client->receive_message);
+ close(client->fd);
+ client->fd = -1;
+
+ client->timeout_resend =
+ sd_event_source_unref(client->timeout_resend);
+
+ client->state = DHCP_STATE_REQUESTING;
+ }
+
+ break;
+
+ case DHCP_STATE_INIT:
+ 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;
+ }
+
+error:
+ 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->xid = random_u();
- return client_send_discover(client);
+ client->fd = dhcp_network_bind_raw_socket(client->index,
+ &client->link);
+
+ if (client->fd < 0) {
+ err = client->fd;
+ goto error;
+ }
+
+ err = sd_event_add_io(client->event, client->fd, EPOLLIN,
+ client_receive_raw_message, client,
+ &client->receive_message);
+ if (err < 0)
+ goto error;
+
+ 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;
}
-sd_dhcp_client *sd_dhcp_client_new(void)
+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;
+ client->fd = -1;
client->req_opts_size = ELEMENTSOF(default_req_opts);
~ianmdlvl / elogind.git / blobdiff