X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibsystemd-network%2Fsd-dhcp-client.c;h=2ddb9ad1dca6bcdec44981b4171b0d33f7d03c35;hp=06b2d1c60d3072eaeb99d1aede8baf27b482f35a;hb=ccfdc9a11256dc9b88860583924b5e57a9bb4ed1;hpb=9f2a50a3005a771a3b6cea2136b6a6c7e5686a0e diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index 06b2d1c60..2ddb9ad1d 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -22,11 +22,14 @@ #include #include #include +#include +#include #include #include #include "util.h" #include "list.h" +#include "refcnt.h" #include "dhcp-protocol.h" #include "dhcp-internal.h" @@ -34,6 +37,8 @@ #include "sd-dhcp-client.h" struct sd_dhcp_client { + RefCount n_ref; + DHCPState state; sd_event *event; int event_priority; @@ -76,6 +81,7 @@ 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); +static sd_dhcp_client *client_stop(sd_dhcp_client *client, int error); int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb, void *userdata) { @@ -91,7 +97,8 @@ 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); + assert_return (IN_SET(client->state, DHCP_STATE_INIT, + DHCP_STATE_STOPPED), -EBUSY); switch(option) { case DHCP_OPTION_PAD: @@ -121,7 +128,8 @@ int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) { 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); + assert_return (IN_SET(client->state, DHCP_STATE_INIT, + DHCP_STATE_STOPPED), -EBUSY); if (last_addr) client->last_addr = last_addr->s_addr; @@ -133,8 +141,9 @@ int sd_dhcp_client_set_request_address(sd_dhcp_client *client, 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); + assert_return (IN_SET(client->state, DHCP_STATE_INIT, + DHCP_STATE_STOPPED), -EBUSY); + assert_return(interface_index > 0, -EINVAL); client->index = interface_index; @@ -151,17 +160,20 @@ int sd_dhcp_client_set_mac(sd_dhcp_client *client, if (memcmp(&client->client_id.mac_addr, addr, ETH_ALEN) == 0) return 0; - if (client->state != DHCP_STATE_INIT) { + if (!IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED)) { log_dhcp_client(client, "Changing MAC address on running DHCP " "client, restarting"); - sd_dhcp_client_stop(client); need_restart = true; + client = client_stop(client, DHCP_EVENT_STOP); } + if (!client) + return 0; + memcpy(&client->client_id.mac_addr, addr, ETH_ALEN); client->client_id.type = 0x01; - if (need_restart) + if (need_restart && client->state != DHCP_STATE_STOPPED) sd_dhcp_client_start(client); return 0; @@ -181,11 +193,14 @@ int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) { return 0; } -static int client_notify(sd_dhcp_client *client, int event) { - if (client->cb) +static sd_dhcp_client *client_notify(sd_dhcp_client *client, int event) { + if (client->cb) { + client = sd_dhcp_client_ref(client); client->cb(client, event, client->userdata); + client = sd_dhcp_client_unref(client); + } - return 0; + return client; } static int client_initialize(sd_dhcp_client *client) { @@ -213,20 +228,36 @@ static int client_initialize(sd_dhcp_client *client) { return 0; } -static int client_stop(sd_dhcp_client *client, int error) { - assert_return(client, -EINVAL); +static sd_dhcp_client *client_stop(sd_dhcp_client *client, int error) { + assert_return(client, NULL); - client_notify(client, error); + if (error < 0) + log_dhcp_client(client, "STOPPED: %s", strerror(-error)); + else { + switch(error) { + case DHCP_EVENT_STOP: + log_dhcp_client(client, "STOPPED: Requested by user"); + break; + case DHCP_EVENT_NO_LEASE: + log_dhcp_client(client, "STOPPED: No lease"); + break; + default: + log_dhcp_client(client, "STOPPED: Unknown reason"); + break; + } + } - client_initialize(client); + client = client_notify(client, error); - log_dhcp_client(client, "STOPPED"); + if (client) + client_initialize(client); - return 0; + return client; } static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, uint8_t type, uint8_t **opt, size_t *optlen) { + be16_t max_size; int r; assert(client); @@ -234,6 +265,7 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, assert(message); assert(opt); assert(optlen); + assert(type == DHCP_DISCOVER || type == DHCP_REQUEST); r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt, optlen); @@ -244,12 +276,12 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, refuse to issue an DHCP lease if 'secs' is set to zero */ message->secs = htobe16(client->secs); + /* RFC2132 section 4.1.1: + The client MUST include its hardware address in the ’chaddr’ field, if + necessary for delivery of DHCP reply messages. + */ memcpy(&message->chaddr, &client->client_id.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, @@ -257,27 +289,37 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, 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; + /* RFC2131 section 3.5: + in its initial DHCPDISCOVER or DHCPREQUEST message, a + client may provide the server with a list of specific + parameters the client is interested in. If the client + includes a list of parameters in a DHCPDISCOVER message, + it MUST include that list in any subsequent DHCPREQUEST + messages. + */ + 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; - } + /* RFC2131 section 3.5: + The client SHOULD include the ’maximum DHCP message size’ option to + let the server know how large the server may make its DHCP messages. + + Note (from ConnMan): 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; } @@ -299,6 +341,10 @@ static int client_send_discover(sd_dhcp_client *client) { int r; assert(client); + assert(client->state == DHCP_STATE_INIT || + client->state == DHCP_STATE_SELECTING); + + /* See RFC2131 section 4.4.1 */ r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now); if (r < 0) @@ -321,6 +367,12 @@ static int client_send_discover(sd_dhcp_client *client) { if (r < 0) return r; + /* the client may suggest values for the network address + and lease time in the DHCPDISCOVER message. The client may include + the ’requested IP address’ option to suggest that a particular IP + address be assigned, and may include the ’IP address lease time’ + option to suggest the lease time it would like. + */ if (client->last_addr != INADDR_ANY) { r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_REQUESTED_IP_ADDRESS, @@ -333,6 +385,10 @@ static int client_send_discover(sd_dhcp_client *client) { if (r < 0) return r; + /* We currently ignore: + The client SHOULD wait a random time between one and ten seconds to + desynchronize the use of DHCP at startup. + */ r = dhcp_client_send_raw(client, discover, len - optlen); if (r < 0) return r; @@ -361,37 +417,66 @@ static int client_send_request(sd_dhcp_client *client) { return r; switch (client->state) { + /* See RFC2131 section 4.3.2 (note that there is a typo in the RFC, + SELECTING should be REQUESTING) + */ + + case DHCP_STATE_REQUESTING: + /* Client inserts the address of the selected server in ’server + identifier’, ’ciaddr’ MUST be zero, ’requested IP address’ MUST be + filled in with the yiaddr value from the chosen DHCPOFFER. + */ - case DHCP_STATE_INIT_REBOOT: r = dhcp_option_append(&opt, &optlen, - DHCP_OPTION_REQUESTED_IP_ADDRESS, - 4, &client->last_addr); + DHCP_OPTION_SERVER_IDENTIFIER, + 4, &client->lease->server_address); if (r < 0) return r; - break; - case DHCP_STATE_REQUESTING: r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_REQUESTED_IP_ADDRESS, 4, &client->lease->address); if (r < 0) return r; + break; + + case DHCP_STATE_INIT_REBOOT: + /* ’server identifier’ MUST NOT be filled in, ’requested IP address’ + option MUST be filled in with client’s notion of its previously + assigned address. ’ciaddr’ MUST be zero. + */ r = dhcp_option_append(&opt, &optlen, - DHCP_OPTION_SERVER_IDENTIFIER, - 4, &client->lease->server_address); + DHCP_OPTION_REQUESTED_IP_ADDRESS, + 4, &client->last_addr); if (r < 0) return r; break; - case DHCP_STATE_INIT: - case DHCP_STATE_SELECTING: - case DHCP_STATE_REBOOTING: - case DHCP_STATE_BOUND: case DHCP_STATE_RENEWING: + /* ’server identifier’ MUST NOT be filled in, ’requested IP address’ + option MUST NOT be filled in, ’ciaddr’ MUST be filled in with + client’s IP address. + */ + + /* fall through */ case DHCP_STATE_REBINDING: + /* ’server identifier’ MUST NOT be filled in, ’requested IP address’ + option MUST NOT be filled in, ’ciaddr’ MUST be filled in with + client’s IP address. + + This message MUST be broadcast to the 0xffffffff IP broadcast address. + */ + request->dhcp.ciaddr = client->lease->address; break; + + case DHCP_STATE_INIT: + case DHCP_STATE_SELECTING: + case DHCP_STATE_REBOOTING: + case DHCP_STATE_BOUND: + case DHCP_STATE_STOPPED: + return -EINVAL; } r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL); @@ -410,11 +495,29 @@ static int client_send_request(sd_dhcp_client *client) { if (r < 0) return r; - log_dhcp_client(client, "REQUEST"); + switch (client->state) { + case DHCP_STATE_REQUESTING: + log_dhcp_client(client, "REQUEST (requesting)"); + break; + case DHCP_STATE_INIT_REBOOT: + log_dhcp_client(client, "REQUEST (init-reboot)"); + break; + case DHCP_STATE_RENEWING: + log_dhcp_client(client, "REQUEST (renewing)"); + break; + case DHCP_STATE_REBINDING: + log_dhcp_client(client, "REQUEST (rebinding)"); + break; + default: + log_dhcp_client(client, "REQUEST (invalid)"); + break; + } return 0; } +static int client_start(sd_dhcp_client *client); + static int client_timeout_resend(sd_event_source *s, uint64_t usec, void *userdata) { sd_dhcp_client *client = userdata; @@ -453,11 +556,18 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec, case DHCP_STATE_REBOOTING: /* start over as we did not receive a timely ack or nak */ - client->state = DHCP_STATE_INIT; - client->attempt = 1; - client->xid = random_u32(); + r = client_initialize(client); + if (r < 0) + goto error; + + r = client_start(client); + if (r < 0) + goto error; + else { + log_dhcp_client(client, "REBOOTED"); + return 0; + } - /* fall through */ case DHCP_STATE_INIT: case DHCP_STATE_INIT_REBOOT: case DHCP_STATE_SELECTING: @@ -470,6 +580,10 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec, next_timeout = time_now + (client->attempt - 1) * USEC_PER_SEC; break; + + case DHCP_STATE_STOPPED: + r = -EINVAL; + goto error; } next_timeout += (random_u32() & 0x1fffff); @@ -528,6 +642,10 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec, case DHCP_STATE_BOUND: break; + + case DHCP_STATE_STOPPED: + r = -EINVAL; + goto error; } return 0; @@ -592,8 +710,7 @@ static int client_start(sd_dhcp_client *client) { client->xid = random_u32(); - r = dhcp_network_bind_raw_socket(client->index, &client->link); - + r = dhcp_network_bind_raw_socket(client->index, &client->link, client->xid); if (r < 0) { client_stop(client, r); return r; @@ -605,8 +722,6 @@ static int client_start(sd_dhcp_client *client) { client->secs = 0; } - log_dhcp_client(client, "STARTED"); - return client_initialize_events(client, client_receive_message_raw); } @@ -616,11 +731,13 @@ static int client_timeout_expire(sd_event_source *s, uint64_t usec, log_dhcp_client(client, "EXPIRED"); - client_notify(client, DHCP_EVENT_EXPIRED); + client = client_notify(client, DHCP_EVENT_EXPIRED); - /* start over as the lease was lost */ - client_initialize(client); - client_start(client); + /* lease was lost, start over if not freed or stopped in callback */ + if (client && client->state != DHCP_STATE_STOPPED) { + client_initialize(client); + client_start(client); + } return 0; } @@ -635,16 +752,13 @@ static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) client->state = DHCP_STATE_REBINDING; client->attempt = 1; - r = dhcp_network_bind_raw_socket(client->index, &client->link); + r = dhcp_network_bind_raw_socket(client->index, &client->link, client->xid); 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); } @@ -666,8 +780,6 @@ static int client_timeout_t1(sd_event_source *s, uint64_t usec, client->fd = r; - log_dhcp_client(client, "TIMEOUT T1"); - return client_initialize_events(client, client_receive_message_udp); } @@ -708,6 +820,7 @@ static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer, } } + sd_dhcp_lease_unref(client->lease); client->lease = lease; lease = NULL; @@ -930,9 +1043,8 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, assert(client->event); assert(message); - if (len < DHCP_MESSAGE_SIZE) { - log_dhcp_client(client, "message too small (%d bytes): " - "ignoring", len); + if (be32toh(message->magic) != DHCP_MAGIC_COOKIE) { + log_dhcp_client(client, "not a DHCP message: ignoring"); return 0; } @@ -948,6 +1060,11 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, return 0; } + if (message->htype != ARPHRD_ETHER || message->hlen != ETHER_ADDR_LEN) { + log_dhcp_client(client, "not an ethernet packet"); + return 0; + } + if (memcmp(&message->chaddr[0], &client->client_id.mac_addr, ETH_ALEN)) { log_dhcp_client(client, "received chaddr does not match " @@ -1004,6 +1121,8 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, r = client_start(client); if (r < 0) goto error; + + log_dhcp_client(client, "REBOOTED"); } goto error; @@ -1026,8 +1145,12 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, if (r < 0) goto error; - if (notify_event) - client_notify(client, notify_event); + if (notify_event) { + client = client_notify(client, notify_event); + if (!client || + client->state == DHCP_STATE_STOPPED) + return 0; + } client->receive_message = sd_event_source_unref(client->receive_message); @@ -1043,13 +1166,17 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, case DHCP_STATE_BOUND: break; + + case DHCP_STATE_STOPPED: + r = -EINVAL; + goto error; } error: if (r < 0 || r == DHCP_EVENT_NO_LEASE) - return client_stop(client, r); + client_stop(client, r); - return 0; + return r; } static int client_receive_message_udp(sd_event_source *s, int fd, @@ -1070,7 +1197,11 @@ static int client_receive_message_udp(sd_event_source *s, int fd, return -ENOMEM; len = read(fd, message, buflen); - if (len < 0) + if (len < 0) { + log_dhcp_client(client, "could not receive message from UDP " + "socket: %s", strerror(errno)); + return 0; + } else if ((size_t)len < sizeof(DHCPMessage)) return 0; return client_handle_message(client, message, len); @@ -1111,11 +1242,14 @@ static int client_receive_message_raw(sd_event_source *s, int fd, log_dhcp_client(client, "could not receive message from raw " "socket: %s", strerror(errno)); return 0; - } + } else if ((size_t)len < sizeof(DHCPPacket)) + 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); + if (cmsg->cmsg_level == SOL_PACKET && + cmsg->cmsg_type == PACKET_AUXDATA && + cmsg->cmsg_len == CMSG_LEN(sizeof(struct tpacket_auxdata))) { + struct tpacket_auxdata *aux = (struct tpacket_auxdata*)CMSG_DATA(cmsg); checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY); break; @@ -1143,11 +1277,22 @@ int sd_dhcp_client_start(sd_dhcp_client *client) { if (client->last_addr) client->state = DHCP_STATE_INIT_REBOOT; - return client_start(client); + r = client_start(client); + if (r >= 0) + log_dhcp_client(client, "STARTED on ifindex %u with address %s", + client->index, + ether_ntoa(&client->client_id.mac_addr)); + + return r; } int sd_dhcp_client_stop(sd_dhcp_client *client) { - return client_stop(client, DHCP_EVENT_STOP); + assert_return(client, -EINVAL); + + if (client_stop(client, DHCP_EVENT_STOP)) + client->state = DHCP_STATE_STOPPED; + + return 0; } int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, @@ -1185,19 +1330,37 @@ sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) { return client->event; } -void sd_dhcp_client_free(sd_dhcp_client *client) { - if (!client) - return; +sd_dhcp_client *sd_dhcp_client_ref(sd_dhcp_client *client) { + if (client) + assert_se(REFCNT_INC(client->n_ref) >= 2); + + return client; +} + +sd_dhcp_client *sd_dhcp_client_unref(sd_dhcp_client *client) { + if (client && REFCNT_DEC(client->n_ref) <= 0) { + log_dhcp_client(client, "UNREF"); - sd_dhcp_client_stop(client); - sd_dhcp_client_detach_event(client); + client_initialize(client); + + client->receive_message = + sd_event_source_unref(client->receive_message); + + sd_dhcp_client_detach_event(client); + + sd_dhcp_lease_unref(client->lease); + + free(client->req_opts); + free(client); + + return NULL; + } - free(client->req_opts); - free(client); + return client; } -DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free); -#define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep) +DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_unref); +#define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_unrefp) int sd_dhcp_client_new(sd_dhcp_client **ret) { _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL; @@ -1208,6 +1371,7 @@ int sd_dhcp_client_new(sd_dhcp_client **ret) { if (!client) return -ENOMEM; + client->n_ref = REFCNT_INIT; client->state = DHCP_STATE_INIT; client->index = -1; client->fd = -1;