X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibsystemd-dhcp%2Fdhcp-client.c;h=68a7328348b700a0c29dbe04de40588006d9e8e5;hp=b1bdd385930d90d617b4222ff0f4937eb65324dd;hb=23f30ed31218c6bc01d9a0ecebdace43e67e97ff;hpb=564ba3b0efbcaf8d5881dbfb80d3c0b174ccaba5 diff --git a/src/libsystemd-dhcp/dhcp-client.c b/src/libsystemd-dhcp/dhcp-client.c index b1bdd3859..68a732834 100644 --- a/src/libsystemd-dhcp/dhcp-client.c +++ b/src/libsystemd-dhcp/dhcp-client.c @@ -22,6 +22,7 @@ #include #include #include +#include #include "util.h" #include "list.h" @@ -33,11 +34,13 @@ #define DHCP_CLIENT_MIN_OPTIONS_SIZE 312 struct DHCPLease { + uint32_t t1; + uint32_t t2; uint32_t lifetime; - uint32_t address; - uint32_t server_address; - uint32_t subnet_mask; - uint32_t router; + be32_t address; + be32_t server_address; + be32_t subnet_mask; + be32_t router; }; typedef struct DHCPLease DHCPLease; @@ -52,11 +55,17 @@ struct sd_dhcp_client { sd_event_source *receive_message; uint8_t *req_opts; size_t req_opts_size; - uint32_t last_addr; + 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; }; @@ -69,6 +78,20 @@ static const uint8_t default_req_opts[] = { 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; @@ -137,6 +160,102 @@ int sd_dhcp_client_set_mac(sd_dhcp_client *client, return 0; } +int sd_dhcp_client_get_address(sd_dhcp_client *client, struct in_addr *addr) +{ + assert_return(client, -EINVAL); + assert_return(addr, -EINVAL); + + switch (client->state) { + case DHCP_STATE_INIT: + case DHCP_STATE_SELECTING: + case DHCP_STATE_INIT_REBOOT: + case DHCP_STATE_REBOOTING: + case DHCP_STATE_REQUESTING: + return -EADDRNOTAVAIL; + + case DHCP_STATE_BOUND: + case DHCP_STATE_RENEWING: + case DHCP_STATE_REBINDING: + addr->s_addr = client->lease->address; + + break; + } + + return 0; +} + +int sd_dhcp_client_get_netmask(sd_dhcp_client *client, struct in_addr *addr) +{ + assert_return(client, -EINVAL); + assert_return(addr, -EINVAL); + + switch (client->state) { + case DHCP_STATE_INIT: + case DHCP_STATE_SELECTING: + case DHCP_STATE_INIT_REBOOT: + case DHCP_STATE_REBOOTING: + case DHCP_STATE_REQUESTING: + return -EADDRNOTAVAIL; + + case DHCP_STATE_BOUND: + case DHCP_STATE_RENEWING: + case DHCP_STATE_REBINDING: + addr->s_addr = client->lease->subnet_mask; + + break; + } + + 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); + + switch (client->state) { + case DHCP_STATE_INIT: + case DHCP_STATE_SELECTING: + case DHCP_STATE_INIT_REBOOT: + case DHCP_STATE_REBOOTING: + case DHCP_STATE_REQUESTING: + return -EADDRNOTAVAIL; + + case DHCP_STATE_BOUND: + case DHCP_STATE_RENEWING: + case DHCP_STATE_REBINDING: + addr->s_addr = client->lease->router; + + break; + } + + 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); @@ -152,12 +271,20 @@ static int client_stop(sd_dhcp_client *client, int error) 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; @@ -165,8 +292,6 @@ static int client_stop(sd_dhcp_client *client, int error) 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: @@ -203,6 +328,10 @@ static int client_packet_init(sd_dhcp_client *client, uint8_t type, 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; @@ -261,10 +390,13 @@ static uint16_t client_checksum(void *buf, int len) if (len & 0x01) { odd = buf; - sum += odd[len]; + sum += odd[len - 1]; } - return ~((sum & 0xffff) + (sum >> 16)); + while (sum >> 16) + sum = (sum & 0xffff) + (sum >> 16); + + return ~sum; } static void client_append_ip_headers(DHCPPacket *packet, uint16_t len) @@ -366,10 +498,17 @@ static int client_send_request(sd_dhcp_client *client, uint16_t secs) if (err < 0) return err; - client_append_ip_headers(request, len); + 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); + err = dhcp_network_send_raw_socket(client->fd, &client->link, + request, len); + } return err; } @@ -378,17 +517,48 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec, void *userdata) { sd_dhcp_client *client = userdata; - usec_t next_timeout; + usec_t next_timeout = 0; + uint32_t time_left; uint16_t secs; int err = 0; - secs = (usec - client->start_time) / USEC_PER_SEC; + 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; - if (client->attempt < 64) - client->attempt *= 2; + next_timeout = usec + time_left * USEC_PER_SEC; - next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC + - (random_u() & 0x1fffff); + 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_u() & 0x1fffff); err = sd_event_add_monotonic(client->event, next_timeout, 10 * USEC_PER_MSEC, @@ -397,6 +567,8 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec, if (err < 0) goto error; + secs = (usec - client->start_time) / USEC_PER_SEC; + switch (client->state) { case DHCP_STATE_INIT: err = client_send_discover(client, secs); @@ -418,17 +590,19 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec, break; case DHCP_STATE_REQUESTING: + case DHCP_STATE_RENEWING: + case DHCP_STATE_REBINDING: err = client_send_request(client, secs); if (err < 0 && client->attempt >= 64) goto error; + client->request_sent = usec; + break; case DHCP_STATE_INIT_REBOOT: case DHCP_STATE_REBOOTING: case DHCP_STATE_BOUND: - case DHCP_STATE_RENEWING: - case DHCP_STATE_REBINDING: break; } @@ -443,6 +617,84 @@ error: return 0; } +static int client_initialize_events(sd_dhcp_client *client, usec_t usec) +{ + int r; + + 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_add_monotonic(client->event, usec, 0, + client_timeout_resend, client, + &client->timeout_resend); + +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) { @@ -476,46 +728,74 @@ static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option, memcpy(&lease->router, option, 4); 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_receive_offer(sd_dhcp_client *client, DHCPPacket *offer, - size_t len) +static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message, + 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 = message->ip.ihl * 4; + if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip, hdrlen)) return -EINVAL; - offer->ip.check = offer->udp.len; - offer->ip.ttl = 0; + message->ip.check = message->udp.len; + message->ip.ttl = 0; - if (hdrlen + be16toh(offer->udp.len) > len || - client_checksum(&offer->ip.ttl, be16toh(offer->udp.len) + 12)) + if (hdrlen + be16toh(message->udp.len) > len || + client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12)) return -EINVAL; - if (be16toh(offer->udp.source) != DHCP_PORT_SERVER || - be16toh(offer->udp.dest) != DHCP_PORT_CLIENT) + if (be16toh(message->udp.source) != DHCP_PORT_SERVER || + be16toh(message->udp.dest) != DHCP_PORT_CLIENT) return -EINVAL; - if (offer->dhcp.op != BOOTREPLY) + if (message->dhcp.op != BOOTREPLY) return -EINVAL; - if (be32toh(offer->dhcp.xid) != client->xid) + if (be32toh(message->dhcp.xid) != client->xid) return -EINVAL; - if (memcmp(&offer->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet, + 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) +{ + int err; + DHCPLease *lease; + + err = client_verify_headers(client, offer, len); + if (err < 0) + return err; + lease = new0(DHCPLease, 1); if (!lease) return -ENOMEM; @@ -543,13 +823,150 @@ error: return -ENOMSG; } -static int client_receive_raw_message(sd_event_source *s, int fd, - uint32_t revents, void *userdata) +static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf, + size_t len) +{ + int r; + DHCPPacket *ack; + DHCPMessage *dhcp; + DHCPLease *lease; + + 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) { + r = DHCP_EVENT_NO_LEASE; + goto error; + } + + if (r != DHCP_ACK) { + r = -ENOMSG; + goto error; + } + + lease->address = dhcp->yiaddr; + + if (lease->address == INADDR_ANY || + lease->server_address == INADDR_ANY || + lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) { + r = -ENOMSG; + goto error; + } + + 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; + } + + free(client->lease); + } + + client->lease = lease; + + return r; + +error: + free(lease); + + return r; +} + +static uint64_t client_compute_timeout(uint64_t request_sent, + uint32_t lifetime) +{ + return request_sent + (lifetime - 3) * USEC_PER_SEC + + + (random_u() & 0x1fffff); +} + +static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) +{ + int err; + uint64_t next_timeout; + + 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; + + err = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_t1, client, + &client->timeout_t1); + if (err < 0) + return err; + + 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; + + err = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_t2, client, + &client->timeout_t2); + if (err < 0) + return err; + + next_timeout = client_compute_timeout(client->request_sent, + client->lease->lifetime); + if (next_timeout < usec) + return -EINVAL; + + err = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_expire, client, + &client->timeout_expire); + if (err < 0) + return err; + + 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, err = 0; + int len, r = 0, notify_event = 0; DHCPPacket *message; usec_t time_now; @@ -557,15 +974,15 @@ static int client_receive_raw_message(sd_event_source *s, int fd, if (len < 0) return 0; - err = sd_event_get_now_monotonic(client->event, &time_now); - if (err < 0) + r = sd_event_get_now_monotonic(client->event, &time_now); + if (r < 0) goto error; - message = (DHCPPacket *)&buf; - switch (client->state) { case DHCP_STATE_SELECTING: + message = (DHCPPacket *)&buf; + if (client_receive_offer(client, message, len) >= 0) { client->timeout_resend = @@ -574,77 +991,111 @@ static int client_receive_raw_message(sd_event_source *s, int fd, client->state = DHCP_STATE_REQUESTING; client->attempt = 1; - err = sd_event_add_monotonic(client->event, time_now, 0, - client_timeout_resend, - client, - &client->timeout_resend); - if (err < 0) + r = sd_event_add_monotonic(client->event, time_now, 0, + client_timeout_resend, + client, + &client->timeout_resend); + 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_REQUESTING: case DHCP_STATE_BOUND: - case DHCP_STATE_RENEWING: - case DHCP_STATE_REBINDING: break; } error: - if (err < 0) - return client_stop(client, err); + 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 err; + int r; assert_return(client, -EINVAL); - assert_return(client->index >= 0, -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(); - client->fd = dhcp_network_bind_raw_socket(client->index, - &client->link); + r = dhcp_network_bind_raw_socket(client->index, &client->link); - if (client->fd < 0) { - err = client->fd; - goto error; + if (r < 0) { + client_stop(client, r); + return r; } - err = sd_event_add_io(client->event, client->fd, EPOLLIN, - client_receive_raw_message, client, - &client->receive_message); - if (err < 0) - goto error; - + client->fd = r; client->start_time = now(CLOCK_MONOTONIC); - err = sd_event_add_monotonic(client->event, client->start_time, 0, - client_timeout_resend, client, - &client->timeout_resend); - if (err < 0) - goto error; - return 0; - -error: - client_stop(client, err); - - return err; + return client_initialize_events(client, client->start_time); } int sd_dhcp_client_stop(sd_dhcp_client *client) { - return client_stop(client, 0); + return client_stop(client, DHCP_EVENT_STOP); +} + +sd_dhcp_client *sd_dhcp_client_free(sd_dhcp_client *client) +{ + assert_return(client, NULL); + + sd_dhcp_client_stop(client); + + sd_event_unref(client->event); + free(client->req_opts); + free(client); + + return NULL; } sd_dhcp_client *sd_dhcp_client_new(sd_event *event)