X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibsystemd-dhcp%2Fdhcp-client.c;h=e9c4700081c0168b16bb28329193d2d705876767;hp=85c8040da4123169a01c0481603d8c2268a1e268;hb=d3d8ac2f2bac721d99f893c0a0128d21db636d4c;hpb=011feef852de96a1adaba476037ce01b5efefc35 diff --git a/src/libsystemd-dhcp/dhcp-client.c b/src/libsystemd-dhcp/dhcp-client.c index 85c8040da..e9c470008 100644 --- a/src/libsystemd-dhcp/dhcp-client.c +++ b/src/libsystemd-dhcp/dhcp-client.c @@ -21,19 +21,28 @@ #include #include #include +#include #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[] = { @@ -102,14 +111,270 @@ int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) 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;