diff options
Diffstat (limited to 'src/libsystemd-network/sd-dhcp-client.c')
| -rw-r--r-- | src/libsystemd-network/sd-dhcp-client.c | 1051 |
1 files changed, 1051 insertions, 0 deletions
diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c new file mode 100644 index 0000000000..1f676ccb65 --- /dev/null +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -0,0 +1,1051 @@ +/*** + 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 <sys/ioctl.h> + +#include "util.h" +#include "list.h" + +#include "dhcp-protocol.h" +#include "dhcp-internal.h" +#include "dhcp-lease-internal.h" +#include "sd-dhcp-client.h" + +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; + uint16_t secs; + 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; + sd_dhcp_lease *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_raw(sd_event_source *s, int fd, + uint32_t revents, void *userdata); +static int client_receive_message_udp(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_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) { + assert_return(client, -EINVAL); + assert_return(ret, -EINVAL); + + if (client->state != DHCP_STATE_BOUND && + client->state != DHCP_STATE_RENEWING && + client->state != DHCP_STATE_REBINDING) + return -EADDRNOTAVAIL; + + *ret = sd_dhcp_lease_ref(client->lease); + + return 0; +} + +static int client_notify(sd_dhcp_client *client, int event) { + if (client->cb) + client->cb(client, event, client->userdata); + + return 0; +} + +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); + + client->start_time = 0; + client->secs = 0; + client->state = DHCP_STATE_INIT; + + if (client->lease) + client->lease = sd_dhcp_lease_unref(client->lease); + + log_dhcp_client(client, "STOPPED"); + + return 0; +} + +static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, + uint8_t type, uint16_t secs, uint8_t **opt, + size_t *optlen) { + int r; + + assert(secs); + + r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt, + optlen); + if (r < 0) + return r; + + /* 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); + + if (client->state == DHCP_STATE_RENEWING || + client->state == DHCP_STATE_REBINDING) + message->ciaddr = client->lease->address; + + /* Some DHCP servers will refuse to issue an DHCP lease if the Client + Identifier option is not set */ + r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER, + ETH_ALEN, &client->mac_addr); + if (r < 0) + return r; + + if (type == DHCP_DISCOVER || type == DHCP_REQUEST) { + be16_t max_size; + + r = dhcp_option_append(opt, optlen, + DHCP_OPTION_PARAMETER_REQUEST_LIST, + client->req_opts_size, + client->req_opts); + if (r < 0) + return r; + + /* 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_MIN_OPTIONS_SIZE); + r = dhcp_option_append(opt, optlen, + DHCP_OPTION_MAXIMUM_MESSAGE_SIZE, + 2, &max_size); + if (r < 0) + return r; + } + + return 0; +} + +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_MIN_OPTIONS_SIZE; + len = sizeof(DHCPPacket) + optlen; + + discover = malloc0(len); + + if (!discover) + return -ENOMEM; + + err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER, + 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; + + dhcp_packet_append_ip_headers(discover, len); + + err = dhcp_network_send_raw_socket(client->fd, &client->link, + discover, len); + + log_dhcp_client(client, "DISCOVER"); + + 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_MIN_OPTIONS_SIZE; + len = sizeof(DHCPPacket) + optlen; + + request = malloc0(len); + if (!request) + return -ENOMEM; + + err = client_message_init(client, &request->dhcp, DHCP_REQUEST, 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, + DHCP_PORT_SERVER, + &request->dhcp, + len - DHCP_IP_UDP_SIZE); + } else { + dhcp_packet_append_ip_headers(request, len); + + err = dhcp_network_send_raw_socket(client->fd, &client->link, + request, len); + } + + log_dhcp_client(client, "REQUEST"); + + return err; +} + +static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now) +{ + client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1; + + return client->secs; +} + +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; + 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); + + client->timeout_resend = sd_event_source_unref(client->timeout_resend); + + r = sd_event_add_monotonic(client->event, + &client->timeout_resend, + next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_resend, client); + if (r < 0) + goto error; + + r = sd_event_source_set_priority(client->timeout_resend, + client->event_priority); + if (r < 0) + goto error; + + switch (client->state) { + case DHCP_STATE_INIT: + + client_update_secs(client, usec); + + r = client_send_discover(client, 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: + client_update_secs(client, usec); + + r = client_send_discover(client, 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, 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, + sd_event_io_handler_t io_callback, + usec_t usec) { + int r; + + assert(client); + assert(client->event); + + r = sd_event_add_io(client->event, &client->receive_message, + client->fd, EPOLLIN, io_callback, + client); + if (r < 0) + goto error; + + r = sd_event_source_set_priority(client->receive_message, + client->event_priority); + if (r < 0) + goto error; + + client->timeout_resend = sd_event_source_unref(client->timeout_resend); + + r = sd_event_add_monotonic(client->event, + &client->timeout_resend, + usec, 0, + client_timeout_resend, client); + 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; + + log_dhcp_client(client, "EXPIRED"); + + 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; + + log_dhcp_client(client, "TIMEOUT T2"); + + return client_initialize_events(client, client_receive_message_raw, + 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, + DHCP_PORT_CLIENT); + if (r < 0) { + client_stop(client, r); + return 0; + } + + client->fd = r; + + log_dhcp_client(client, "TIMEOUT T1"); + + return client_initialize_events(client, client_receive_message_udp, usec); +} + +static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer, + size_t len) { + _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL; + int r; + + r = dhcp_lease_new(&lease); + if (r < 0) + return r; + + r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease); + if (r != DHCP_OFFER) + return -ENOMSG; + + lease->address = offer->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; + + log_dhcp_client(client, "OFFER"); + + return 0; +} + +static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack, + size_t len) { + _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL; + int r; + + r = dhcp_lease_new(&lease); + if (r < 0) + return r; + + r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease); + if (r == DHCP_NAK) { + log_dhcp_client(client, "NAK"); + return DHCP_EVENT_NO_LEASE; + } + + if (r != DHCP_ACK) + return -ENOMSG; + + lease->address = ack->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; + } + + client->lease = sd_dhcp_lease_unref(client->lease); + } + + client->lease = lease; + lease = NULL; + + log_dhcp_client(client, "ACK"); + + 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, + &client->timeout_t1, + next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_t1, client); + 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, + &client->timeout_t2, + next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_t2, client); + 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, + &client->timeout_expire, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_expire, client); + 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_handle_message(sd_dhcp_client *client, DHCPMessage *message, + int len, usec_t time_now) { + int r = 0, notify_event = 0; + + assert(client); + assert(client->event); + assert(message); + + if (len < DHCP_MESSAGE_SIZE) { + log_dhcp_client(client, "message too small (%d bytes): " + "ignoring", len); + return 0; + } + + if (message->op != BOOTREPLY) { + log_dhcp_client(client, "not a BOOTREPLY message: ignoring"); + return 0; + } + + if (be32toh(message->xid) != client->xid) { + log_dhcp_client(client, "received xid (%u) does not match " + "expected (%u): ignoring", + be32toh(message->xid), client->xid); + return 0; + } + + if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet, + ETHER_ADDR_LEN)) { + log_dhcp_client(client, "received chaddr does not match " + "expected: ignoring"); + return 0; + } + + switch (client->state) { + case DHCP_STATE_SELECTING: + + r = client_handle_offer(client, message, len); + if (r >= 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, + &client->timeout_resend, + time_now, 0, + client_timeout_resend, + client); + 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_handle_ack(client, message, 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; +} + +static int client_receive_message_udp(sd_event_source *s, int fd, + uint32_t revents, void *userdata) { + sd_dhcp_client *client = userdata; + _cleanup_free_ DHCPMessage *message = NULL; + int buflen = 0, len, r; + usec_t time_now; + + assert(s); + assert(client); + assert(client->event); + + r = ioctl(fd, FIONREAD, &buflen); + if (r < 0 || buflen <= 0) + buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE; + + message = malloc0(buflen); + if (!message) + return -ENOMEM; + + len = read(fd, message, buflen); + if (len < 0) + return 0; + + r = sd_event_get_now_monotonic(client->event, &time_now); + if (r < 0) + return client_stop(client, r); + + return client_handle_message(client, message, len, + time_now); +} + +static int client_receive_message_raw(sd_event_source *s, int fd, + uint32_t revents, void *userdata) { + sd_dhcp_client *client = userdata; + _cleanup_free_ DHCPPacket *packet = NULL; + usec_t time_now; + uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))]; + struct iovec iov = {}; + struct msghdr msg = { + .msg_iov = &iov, + .msg_iovlen = 1, + .msg_control = cmsgbuf, + .msg_controllen = sizeof(cmsgbuf), + }; + struct cmsghdr *cmsg; + bool checksum = true; + int buflen = 0, len, r; + + assert(s); + assert(client); + assert(client->event); + + r = ioctl(fd, FIONREAD, &buflen); + if (r < 0 || buflen <= 0) + buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE; + + packet = malloc0(buflen); + if (!packet) + return -ENOMEM; + + iov.iov_base = packet; + iov.iov_len = buflen; + + len = recvmsg(fd, &msg, 0); + if (len < 0) { + log_dhcp_client(client, "could not receive message from raw " + "socket: %s", strerror(errno)); + return 0; + } + + for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { + if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) { + struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg); + + checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY); + break; + } + } + + r = dhcp_packet_verify_headers(packet, len, checksum); + if (r < 0) + return 0; + + len -= DHCP_IP_UDP_SIZE; + + r = sd_event_get_now_monotonic(client->event, &time_now); + if (r < 0) + return client_stop(client, r); + + return client_handle_message(client, &packet->dhcp, len, time_now); +} + +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); + client->secs = 0; + + log_dhcp_client(client, "STARTED"); + + return client_initialize_events(client, client_receive_message_raw, + 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; +} |