diff options
Diffstat (limited to 'src/libsystemd-dhcp/sd-dhcp-client.c')
| -rw-r--r-- | src/libsystemd-dhcp/sd-dhcp-client.c | 1254 |
1 files changed, 1254 insertions, 0 deletions
diff --git a/src/libsystemd-dhcp/sd-dhcp-client.c b/src/libsystemd-dhcp/sd-dhcp-client.c new file mode 100644 index 0000000000..3b7b9f4ccd --- /dev/null +++ b/src/libsystemd-dhcp/sd-dhcp-client.c @@ -0,0 +1,1254 @@ +/*** + This file is part of systemd. + + Copyright (C) 2013 Intel Corporation. All rights reserved. + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <stdlib.h> +#include <errno.h> +#include <string.h> +#include <stdio.h> +#include <net/ethernet.h> +#include <sys/param.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 + +#define client_state_machine_check(s, r) \ + do { \ + if (s != DHCP_STATE_BOUND && \ + s != DHCP_STATE_RENEWING && \ + s != DHCP_STATE_REBINDING) { \ + return (r); \ + } \ + } while (false) + +struct DHCPLease { + uint32_t t1; + uint32_t t2; + uint32_t lifetime; + be32_t address; + be32_t server_address; + be32_t subnet_mask; + be32_t router; + struct in_addr *dns; + size_t dns_size; + uint16_t mtu; + char *domainname; + char *hostname; +}; + +typedef struct DHCPLease DHCPLease; + +struct sd_dhcp_client { + DHCPState state; + sd_event *event; + int event_priority; + 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_allocated; + size_t req_opts_size; + be32_t last_addr; + struct ether_addr mac_addr; + uint32_t xid; + usec_t start_time; + unsigned int attempt; + usec_t request_sent; + sd_event_source *timeout_t1; + sd_event_source *timeout_t2; + sd_event_source *timeout_expire; + sd_dhcp_client_cb_t cb; + void *userdata; + DHCPLease *lease; +}; + +static const uint8_t default_req_opts[] = { + DHCP_OPTION_SUBNET_MASK, + DHCP_OPTION_ROUTER, + DHCP_OPTION_HOST_NAME, + DHCP_OPTION_DOMAIN_NAME, + DHCP_OPTION_DOMAIN_NAME_SERVER, + DHCP_OPTION_NTP_SERVER, +}; + +static int client_receive_message(sd_event_source *s, int fd, + uint32_t revents, void *userdata); + +int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb, + void *userdata) { + assert_return(client, -EINVAL); + + client->cb = cb; + client->userdata = userdata; + + return 0; +} + +int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) { + size_t i; + + assert_return(client, -EINVAL); + assert_return (client->state == DHCP_STATE_INIT, -EBUSY); + + switch(option) { + case DHCP_OPTION_PAD: + case DHCP_OPTION_OVERLOAD: + case DHCP_OPTION_MESSAGE_TYPE: + case DHCP_OPTION_PARAMETER_REQUEST_LIST: + case DHCP_OPTION_END: + return -EINVAL; + + default: + break; + } + + for (i = 0; i < client->req_opts_size; i++) + if (client->req_opts[i] == option) + return -EEXIST; + + if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated, + client->req_opts_size + 1)) + return -ENOMEM; + + client->req_opts[client->req_opts_size++] = option; + + return 0; +} + +int sd_dhcp_client_set_request_address(sd_dhcp_client *client, + const struct in_addr *last_addr) { + assert_return(client, -EINVAL); + assert_return(client->state == DHCP_STATE_INIT, -EBUSY); + + if (last_addr) + client->last_addr = last_addr->s_addr; + else + client->last_addr = INADDR_ANY; + + return 0; +} + +int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) { + assert_return(client, -EINVAL); + assert_return(client->state == DHCP_STATE_INIT, -EBUSY); + assert_return(interface_index >= -1, -EINVAL); + + client->index = interface_index; + + return 0; +} + +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; +} + +int sd_dhcp_client_get_address(sd_dhcp_client *client, struct in_addr *addr) { + assert_return(client, -EINVAL); + assert_return(addr, -EINVAL); + + client_state_machine_check (client->state, -EADDRNOTAVAIL); + + addr->s_addr = client->lease->address; + + return 0; +} + +int sd_dhcp_client_get_mtu(sd_dhcp_client *client, uint16_t *mtu) { + assert_return(client, -EINVAL); + assert_return(mtu, -EINVAL); + + client_state_machine_check (client->state, -EADDRNOTAVAIL); + + if (client->lease->mtu) + *mtu = client->lease->mtu; + else + return -ENOENT; + + return 0; +} + +int sd_dhcp_client_get_dns(sd_dhcp_client *client, struct in_addr **addr, size_t *addr_size) { + assert_return(client, -EINVAL); + assert_return(addr, -EINVAL); + assert_return(addr_size, -EINVAL); + + client_state_machine_check (client->state, -EADDRNOTAVAIL); + + if (client->lease->dns_size) { + *addr_size = client->lease->dns_size; + *addr = client->lease->dns; + } else + return -ENOENT; + + return 0; +} + +int sd_dhcp_client_get_domainname(sd_dhcp_client *client, const char **domainname) { + assert_return(client, -EINVAL); + assert_return(domainname, -EINVAL); + + client_state_machine_check (client->state, -EADDRNOTAVAIL); + + if (client->lease->domainname) + *domainname = client->lease->domainname; + else + return -ENOENT; + + return 0; +} + +int sd_dhcp_client_get_hostname(sd_dhcp_client *client, const char **hostname) { + assert_return(client, -EINVAL); + assert_return(hostname, -EINVAL); + + client_state_machine_check (client->state, -EADDRNOTAVAIL); + + if (client->lease->hostname) + *hostname = client->lease->hostname; + else + return -ENOENT; + + return 0; +} + +int sd_dhcp_client_prefixlen(const struct in_addr *addr) { + int len = 0; + uint32_t mask; + + assert_return(addr, -EADDRNOTAVAIL); + + mask = be32toh(addr->s_addr); + while (mask) { + len++; + mask = mask << 1; + } + + return len; +} + +int sd_dhcp_client_get_router(sd_dhcp_client *client, struct in_addr *addr) { + assert_return(client, -EINVAL); + assert_return(addr, -EINVAL); + + client_state_machine_check (client->state, -EADDRNOTAVAIL); + + addr->s_addr = client->lease->router; + + return 0; +} + +int sd_dhcp_client_get_netmask(sd_dhcp_client *client, struct in_addr *addr) { + assert_return(client, -EINVAL); + assert_return(addr, -EINVAL); + + client_state_machine_check (client->state, -EADDRNOTAVAIL); + + addr->s_addr = client->lease->subnet_mask; + + return 0; +} + +static int client_notify(sd_dhcp_client *client, int event) { + if (client->cb) + client->cb(client, event, client->userdata); + + return 0; +} + +static void lease_free(DHCPLease *lease) { + if (!lease) + return; + + free(lease->hostname); + free(lease->domainname); + free(lease->dns); + free(lease); +} + +DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPLease*, lease_free); +#define _cleanup_lease_free_ _cleanup_(lease_freep) + +static int client_stop(sd_dhcp_client *client, int error) { + assert_return(client, -EINVAL); + + 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); + + client->timeout_t1 = sd_event_source_unref(client->timeout_t1); + client->timeout_t2 = sd_event_source_unref(client->timeout_t2); + client->timeout_expire = sd_event_source_unref(client->timeout_expire); + + client->attempt = 1; + + client_notify(client, error); + + switch (client->state) { + + case DHCP_STATE_INIT: + case DHCP_STATE_SELECTING: + case DHCP_STATE_REQUESTING: + case DHCP_STATE_BOUND: + + client->start_time = 0; + client->state = DHCP_STATE_INIT; + break; + + case DHCP_STATE_INIT_REBOOT: + case DHCP_STATE_REBOOTING: + case DHCP_STATE_RENEWING: + case DHCP_STATE_REBINDING: + + break; + } + + if (client->lease) { + lease_free(client->lease); + client->lease = NULL; + } + + 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; + be16_t max_size; + + *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); + + if (client->state == DHCP_STATE_RENEWING || + client->state == DHCP_STATE_REBINDING) + message->ciaddr = client->lease->address; + + 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; + + /* Some DHCP servers will send bigger DHCP packets than the + defined default size unless the Maximum Messge Size option + is explicitely set */ + max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE + + DHCP_CLIENT_MIN_OPTIONS_SIZE); + err = dhcp_option_append(opt, optlen, + DHCP_OPTION_MAXIMUM_MESSAGE_SIZE, + 2, &max_size); + 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 - 1]; + } + + while (sum >> 16) + sum = (sum & 0xffff) + (sum >> 16); + + return ~sum; +} + +static void client_append_ip_headers(DHCPPacket *packet, uint16_t len) { + packet->ip.version = IPVERSION; + packet->ip.ihl = DHCP_IP_SIZE / 4; + packet->ip.tot_len = htobe16(len); + + packet->ip.protocol = IPPROTO_UDP; + packet->ip.saddr = INADDR_ANY; + packet->ip.daddr = INADDR_BROADCAST; + + packet->udp.source = htobe16(DHCP_PORT_CLIENT); + packet->udp.dest = htobe16(DHCP_PORT_SERVER); + packet->udp.len = htobe16(len - DHCP_IP_SIZE); + + packet->ip.check = packet->udp.len; + packet->udp.check = client_checksum(&packet->ip.ttl, len - 8); + + packet->ip.ttl = IPDEFTTL; + packet->ip.check = 0; + packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE); +} + +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; + + client_append_ip_headers(discover, len); + + err = dhcp_network_send_raw_socket(client->fd, &client->link, + discover, len); + + return err; +} + +static int client_send_request(sd_dhcp_client *client, uint16_t secs) { + _cleanup_free_ DHCPPacket *request; + size_t optlen, len; + int err; + uint8_t *opt; + + optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE; + len = DHCP_MESSAGE_SIZE + optlen; + + request = malloc0(len); + if (!request) + return -ENOMEM; + + err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs, + &opt, &optlen); + if (err < 0) + return err; + + if (client->state == DHCP_STATE_REQUESTING) { + err = dhcp_option_append(&opt, &optlen, + DHCP_OPTION_REQUESTED_IP_ADDRESS, + 4, &client->lease->address); + if (err < 0) + return err; + + err = dhcp_option_append(&opt, &optlen, + DHCP_OPTION_SERVER_IDENTIFIER, + 4, &client->lease->server_address); + if (err < 0) + return err; + } + + err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL); + if (err < 0) + return err; + + if (client->state == DHCP_STATE_RENEWING) { + err = dhcp_network_send_udp_socket(client->fd, + client->lease->server_address, + &request->dhcp, + len - DHCP_IP_UDP_SIZE); + } else { + client_append_ip_headers(request, len); + + err = dhcp_network_send_raw_socket(client->fd, &client->link, + request, 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 = 0; + uint32_t time_left; + uint16_t secs; + int r = 0; + + assert(s); + assert(client); + assert(client->event); + + switch (client->state) { + case DHCP_STATE_RENEWING: + + time_left = (client->lease->t2 - client->lease->t1)/2; + if (time_left < 60) + time_left = 60; + + next_timeout = usec + time_left * USEC_PER_SEC; + + break; + + case DHCP_STATE_REBINDING: + + time_left = (client->lease->lifetime - client->lease->t2)/2; + if (time_left < 60) + time_left = 60; + + next_timeout = usec + time_left * USEC_PER_SEC; + break; + + case DHCP_STATE_INIT: + case DHCP_STATE_INIT_REBOOT: + case DHCP_STATE_REBOOTING: + case DHCP_STATE_SELECTING: + case DHCP_STATE_REQUESTING: + case DHCP_STATE_BOUND: + + if (client->attempt < 64) + client->attempt *= 2; + + next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC; + + break; + } + + next_timeout += (random_u32() & 0x1fffff); + + r = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_resend, client, + &client->timeout_resend); + if (r < 0) + goto error; + + r = sd_event_source_set_priority(client->timeout_resend, client->event_priority); + if (r < 0) + goto error; + + secs = (usec - client->start_time) / USEC_PER_SEC; + + switch (client->state) { + case DHCP_STATE_INIT: + r = client_send_discover(client, secs); + if (r >= 0) { + client->state = DHCP_STATE_SELECTING; + client->attempt = 1; + } else { + if (client->attempt >= 64) + goto error; + } + + break; + + case DHCP_STATE_SELECTING: + r = client_send_discover(client, secs); + if (r < 0 && client->attempt >= 64) + goto error; + + break; + + case DHCP_STATE_REQUESTING: + case DHCP_STATE_RENEWING: + case DHCP_STATE_REBINDING: + r = client_send_request(client, secs); + if (r < 0 && client->attempt >= 64) + goto error; + + client->request_sent = usec; + + break; + + case DHCP_STATE_INIT_REBOOT: + case DHCP_STATE_REBOOTING: + case DHCP_STATE_BOUND: + + break; + } + + return 0; + +error: + client_stop(client, r); + + /* Errors were dealt with when stopping the client, don't spill + errors into the event loop handler */ + return 0; +} + +static int client_initialize_events(sd_dhcp_client *client, usec_t usec) { + int r; + + assert(client); + assert(client->event); + + r = sd_event_add_io(client->event, client->fd, EPOLLIN, + client_receive_message, client, + &client->receive_message); + if (r < 0) + goto error; + + r = sd_event_source_set_priority(client->receive_message, client->event_priority); + if (r < 0) + goto error; + + r = sd_event_add_monotonic(client->event, usec, 0, + client_timeout_resend, client, + &client->timeout_resend); + if (r < 0) + goto error; + + r = sd_event_source_set_priority(client->timeout_resend, client->event_priority); + +error: + if (r < 0) + client_stop(client, r); + + return 0; + +} + +static int client_timeout_expire(sd_event_source *s, uint64_t usec, + void *userdata) { + sd_dhcp_client *client = userdata; + + client_stop(client, DHCP_EVENT_EXPIRED); + + return 0; +} + +static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) { + sd_dhcp_client *client = userdata; + int r; + + if (client->fd >= 0) { + client->receive_message = + sd_event_source_unref(client->receive_message); + close(client->fd); + client->fd = -1; + } + + client->state = DHCP_STATE_REBINDING; + client->attempt = 1; + + r = dhcp_network_bind_raw_socket(client->index, &client->link); + if (r < 0) { + client_stop(client, r); + return 0; + } + + client->fd = r; + + return client_initialize_events(client, usec); +} + +static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) { + sd_dhcp_client *client = userdata; + int r; + + client->state = DHCP_STATE_RENEWING; + client->attempt = 1; + + r = dhcp_network_bind_udp_socket(client->index, + client->lease->address); + if (r < 0) { + client_stop(client, r); + return 0; + } + + client->fd = r; + + return client_initialize_events(client, usec); +} + +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; + + case DHCP_OPTION_DOMAIN_NAME_SERVER: + if (len >= 4) { + unsigned i; + + lease->dns_size = len / 4; + + free(lease->dns); + lease->dns = new0(struct in_addr, lease->dns_size); + if (!lease->dns) + return -ENOMEM; + + for (i = 0; i < lease->dns_size; i++) { + memcpy(&lease->dns[i].s_addr, option + 4 * i, 4); + } + } + + break; + + case DHCP_OPTION_INTERFACE_MTU: + if (len >= 2) { + be16_t mtu; + + memcpy(&mtu, option, 2); + lease->mtu = be16toh(mtu); + + if (lease->mtu < 68) + lease->mtu = 0; + } + + break; + + case DHCP_OPTION_DOMAIN_NAME: + if (len >= 1) { + free(lease->domainname); + lease->domainname = strndup((const char *)option, len); + } + + break; + + case DHCP_OPTION_HOST_NAME: + if (len >= 1) { + free(lease->hostname); + lease->hostname = strndup((const char *)option, len); + } + + break; + + case DHCP_OPTION_RENEWAL_T1_TIME: + if (len == 4) { + memcpy(&val, option, 4); + lease->t1 = be32toh(val); + } + + break; + + case DHCP_OPTION_REBINDING_T2_TIME: + if (len == 4) { + memcpy(&val, option, 4); + lease->t2 = be32toh(val); + } + + break; + } + + return 0; +} + +static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message, + size_t len) { + size_t hdrlen; + + if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE)) + return -EINVAL; + + hdrlen = message->ip.ihl * 4; + if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip, + hdrlen)) + return -EINVAL; + + message->ip.check = message->udp.len; + message->ip.ttl = 0; + + if (hdrlen + be16toh(message->udp.len) > len || + client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12)) + return -EINVAL; + + if (be16toh(message->udp.source) != DHCP_PORT_SERVER || + be16toh(message->udp.dest) != DHCP_PORT_CLIENT) + return -EINVAL; + + if (message->dhcp.op != BOOTREPLY) + return -EINVAL; + + if (be32toh(message->dhcp.xid) != client->xid) + return -EINVAL; + + if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet, + ETHER_ADDR_LEN)) + return -EINVAL; + + return 0; +} + +static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer, + size_t len) { + _cleanup_lease_free_ DHCPLease *lease = NULL; + int r; + + r = client_verify_headers(client, offer, len); + if (r < 0) + return r; + + lease = new0(DHCPLease, 1); + if (!lease) + return -ENOMEM; + + len = len - DHCP_IP_UDP_SIZE; + r = dhcp_option_parse(&offer->dhcp, len, client_parse_offer, + lease); + if (r != DHCP_OFFER) + return -ENOMSG; + + lease->address = offer->dhcp.yiaddr; + + if (lease->address == INADDR_ANY || + lease->server_address == INADDR_ANY || + lease->subnet_mask == INADDR_ANY || + lease->lifetime == 0) + return -ENOMSG; + + client->lease = lease; + lease = NULL; + + return 0; +} + +static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf, + size_t len) { + DHCPPacket *ack; + DHCPMessage *dhcp; + _cleanup_lease_free_ DHCPLease *lease = NULL; + int r; + + if (client->state == DHCP_STATE_RENEWING) { + dhcp = (DHCPMessage *)buf; + } else { + ack = (DHCPPacket *)buf; + + r = client_verify_headers(client, ack, len); + if (r < 0) + return r; + + dhcp = &ack->dhcp; + len -= DHCP_IP_UDP_SIZE; + } + + lease = new0(DHCPLease, 1); + if (!lease) + return -ENOMEM; + + r = dhcp_option_parse(dhcp, len, client_parse_offer, lease); + if (r == DHCP_NAK) + return DHCP_EVENT_NO_LEASE; + + if (r != DHCP_ACK) + return -ENOMSG; + + lease->address = dhcp->yiaddr; + + if (lease->address == INADDR_ANY || + lease->server_address == INADDR_ANY || + lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) + return -ENOMSG; + + r = DHCP_EVENT_IP_ACQUIRE; + if (client->lease) { + if (client->lease->address != lease->address || + client->lease->subnet_mask != lease->subnet_mask || + client->lease->router != lease->router) { + r = DHCP_EVENT_IP_CHANGE; + } + + lease_free(client->lease); + } + + client->lease = lease; + lease = NULL; + + return r; +} + +static uint64_t client_compute_timeout(uint64_t request_sent, + uint32_t lifetime) { + return request_sent + (lifetime - 3) * USEC_PER_SEC + + + (random_u32() & 0x1fffff); +} + +static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) { + uint64_t next_timeout; + int r; + + assert(client); + assert(client->event); + + if (client->lease->lifetime < 10) + return -EINVAL; + + client->timeout_t1 = sd_event_source_unref(client->timeout_t1); + client->timeout_t2 = sd_event_source_unref(client->timeout_t2); + client->timeout_expire = sd_event_source_unref(client->timeout_expire); + + if (!client->lease->t1) + client->lease->t1 = client->lease->lifetime / 2; + + next_timeout = client_compute_timeout(client->request_sent, + client->lease->t1); + if (next_timeout < usec) + return -EINVAL; + + r = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_t1, client, + &client->timeout_t1); + if (r < 0) + return r; + + r = sd_event_source_set_priority(client->timeout_t1, client->event_priority); + if (r < 0) + return r; + + if (!client->lease->t2) + client->lease->t2 = client->lease->lifetime * 7 / 8; + + if (client->lease->t2 < client->lease->t1) + return -EINVAL; + + if (client->lease->lifetime < client->lease->t2) + return -EINVAL; + + next_timeout = client_compute_timeout(client->request_sent, + client->lease->t2); + if (next_timeout < usec) + return -EINVAL; + + r = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_t2, client, + &client->timeout_t2); + if (r < 0) + return r; + + r = sd_event_source_set_priority(client->timeout_t2, client->event_priority); + if (r < 0) + return r; + + next_timeout = client_compute_timeout(client->request_sent, + client->lease->lifetime); + if (next_timeout < usec) + return -EINVAL; + + r = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_expire, client, + &client->timeout_expire); + if (r < 0) + return r; + + r = sd_event_source_set_priority(client->timeout_expire, client->event_priority); + if (r < 0) + return r; + + return 0; +} + +static int client_receive_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, r = 0, notify_event = 0; + DHCPPacket *message; + usec_t time_now; + + assert(s); + assert(client); + assert(client->event); + + len = read(fd, &buf, buflen); + if (len < 0) + return 0; + + r = sd_event_get_now_monotonic(client->event, &time_now); + if (r < 0) + goto error; + + switch (client->state) { + case DHCP_STATE_SELECTING: + + message = (DHCPPacket *)&buf; + + if (client_receive_offer(client, message, len) >= 0) { + + client->timeout_resend = + sd_event_source_unref(client->timeout_resend); + + client->state = DHCP_STATE_REQUESTING; + client->attempt = 1; + + r = sd_event_add_monotonic(client->event, time_now, 0, + client_timeout_resend, + client, + &client->timeout_resend); + if (r < 0) + goto error; + + r = sd_event_source_set_priority(client->timeout_resend, client->event_priority); + if (r < 0) + goto error; + } + + break; + + case DHCP_STATE_REQUESTING: + case DHCP_STATE_RENEWING: + case DHCP_STATE_REBINDING: + + r = client_receive_ack(client, buf, len); + + if (r == DHCP_EVENT_NO_LEASE) + goto error; + + if (r >= 0) { + client->timeout_resend = + sd_event_source_unref(client->timeout_resend); + + if (client->state == DHCP_STATE_REQUESTING) + notify_event = DHCP_EVENT_IP_ACQUIRE; + else if (r != DHCP_EVENT_IP_ACQUIRE) + notify_event = r; + + client->state = DHCP_STATE_BOUND; + client->attempt = 1; + + client->last_addr = client->lease->address; + + r = client_set_lease_timeouts(client, time_now); + if (r < 0) + goto error; + + if (notify_event) + client_notify(client, notify_event); + + client->receive_message = + sd_event_source_unref(client->receive_message); + close(client->fd); + client->fd = -1; + } + + r = 0; + + break; + + case DHCP_STATE_INIT: + case DHCP_STATE_INIT_REBOOT: + case DHCP_STATE_REBOOTING: + case DHCP_STATE_BOUND: + + break; + } + +error: + if (r < 0 || r == DHCP_EVENT_NO_LEASE) + return client_stop(client, r); + + return 0; +} + +int sd_dhcp_client_start(sd_dhcp_client *client) { + int r; + + assert_return(client, -EINVAL); + assert_return(client->event, -EINVAL); + assert_return(client->index > 0, -EINVAL); + assert_return(client->state == DHCP_STATE_INIT || + client->state == DHCP_STATE_INIT_REBOOT, -EBUSY); + + client->xid = random_u32(); + + r = dhcp_network_bind_raw_socket(client->index, &client->link); + + if (r < 0) { + client_stop(client, r); + return r; + } + + client->fd = r; + client->start_time = now(CLOCK_MONOTONIC); + + return client_initialize_events(client, client->start_time); +} + +int sd_dhcp_client_stop(sd_dhcp_client *client) { + return client_stop(client, DHCP_EVENT_STOP); +} + +int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int priority) { + int r; + + assert_return(client, -EINVAL); + assert_return(!client->event, -EBUSY); + + if (event) + client->event = sd_event_ref(event); + else { + r = sd_event_default(&client->event); + if (r < 0) + return 0; + } + + client->event_priority = priority; + + return 0; +} + +int sd_dhcp_client_detach_event(sd_dhcp_client *client) { + assert_return(client, -EINVAL); + + client->event = sd_event_unref(client->event); + + return 0; +} + +sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) { + if (!client) + return NULL; + + return client->event; +} + +void sd_dhcp_client_free(sd_dhcp_client *client) { + if (!client) + return; + + sd_dhcp_client_stop(client); + sd_dhcp_client_detach_event(client); + + free(client->req_opts); + free(client); +} + +DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free); +#define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep) + +int sd_dhcp_client_new(sd_dhcp_client **ret) { + _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL; + + assert_return(ret, -EINVAL); + + client = new0(sd_dhcp_client, 1); + if (!client) + return -ENOMEM; + + client->state = DHCP_STATE_INIT; + client->index = -1; + client->fd = -1; + client->attempt = 1; + + client->req_opts_size = ELEMENTSOF(default_req_opts); + + client->req_opts = memdup(default_req_opts, client->req_opts_size); + if (!client->req_opts) + return -ENOMEM; + + *ret = client; + client = NULL; + + return 0; +} |