X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibsystemd-network%2Fsd-dhcp-client.c;h=2a46624f2e8c328e41c520e3377c96dd15f1c92d;hp=94235cf2f57d1a60ae479be27ccee1db59e28b55;hb=8186d9dda0d3f8a853afe6fdbd605f42151fe165;hpb=699370c98d37e4b373795f62cba9ff7bade5f2a1 diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index 94235cf2f..2a46624f2 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -256,36 +256,55 @@ static sd_dhcp_client *client_stop(sd_dhcp_client *client, int error) { return client; } -static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, - uint8_t type, uint8_t **opt, size_t *optlen) { +static int client_message_init(sd_dhcp_client *client, DHCPPacket **ret, + uint8_t type, size_t *_optlen, size_t *_optoffset) { + _cleanup_free_ DHCPPacket *packet; + size_t optlen, optoffset, size; be16_t max_size; int r; assert(client); assert(client->secs); - assert(message); - assert(opt); - assert(optlen); + assert(ret); + assert(_optlen); + assert(_optoffset); assert(type == DHCP_DISCOVER || type == DHCP_REQUEST); - r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt, - optlen); + optlen = DHCP_MIN_OPTIONS_SIZE; + size = sizeof(DHCPPacket) + optlen; + + packet = malloc0(size); + if (!packet) + return -ENOMEM; + + r = dhcp_message_init(&packet->dhcp, BOOTREQUEST, client->xid, type, + optlen, &optoffset); 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(client->secs); + packet->dhcp.secs = htobe16(client->secs); + + /* RFC2132 section 4.1 + A client that cannot receive unicast IP datagrams until its protocol + software has been configured with an IP address SHOULD set the + BROADCAST bit in the 'flags' field to 1 in any DHCPDISCOVER or + DHCPREQUEST messages that client sends. The BROADCAST bit will + provide a hint to the DHCP server and BOOTP relay agent to broadcast + any messages to the client on the client's subnet. */ + packet->dhcp.flags = htobe16(0x8000); /* 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); + memcpy(&packet->dhcp.chaddr, &client->client_id.mac_addr, ETH_ALEN); /* 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, + r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0, + DHCP_OPTION_CLIENT_IDENTIFIER, sizeof(client->client_id), &client->client_id); if (r < 0) return r; @@ -299,10 +318,9 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, it MUST include that list in any subsequent DHCPREQUEST messages. */ - r = dhcp_option_append(opt, optlen, + r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0, DHCP_OPTION_PARAMETER_REQUEST_LIST, - client->req_opts_size, - client->req_opts); + client->req_opts_size, client->req_opts); if (r < 0) return r; @@ -314,14 +332,18 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, 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, + max_size = htobe16(size); + r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0, DHCP_OPTION_MAXIMUM_MESSAGE_SIZE, 2, &max_size); if (r < 0) return r; + *_optlen = optlen; + *_optoffset = optoffset; + *ret = packet; + packet = NULL; + return 0; } @@ -336,8 +358,7 @@ static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet, static int client_send_discover(sd_dhcp_client *client) { _cleanup_free_ DHCPPacket *discover = NULL; - size_t optlen, len; - uint8_t *opt; + size_t optoffset, optlen; usec_t time_now; int r; @@ -356,15 +377,8 @@ static int client_send_discover(sd_dhcp_client *client) { * must always be strictly positive to deal with broken servers */ client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1; - optlen = DHCP_MIN_OPTIONS_SIZE; - len = sizeof(DHCPPacket) + optlen; - - discover = malloc0(len); - if (!discover) - return -ENOMEM; - - r = client_message_init(client, &discover->dhcp, DHCP_DISCOVER, - &opt, &optlen); + r = client_message_init(client, &discover, DHCP_DISCOVER, + &optlen, &optoffset); if (r < 0) return r; @@ -375,22 +389,21 @@ static int client_send_discover(sd_dhcp_client *client) { 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, - 4, &client->last_addr); + r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0, + DHCP_OPTION_REQUESTED_IP_ADDRESS, + 4, &client->last_addr); if (r < 0) return r; } - r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL); - if (r < 0) - return r; + r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0, + DHCP_OPTION_END, 0, NULL); /* 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); + r = dhcp_client_send_raw(client, discover, sizeof(DHCPPacket) + optoffset); if (r < 0) return r; @@ -400,20 +413,12 @@ static int client_send_discover(sd_dhcp_client *client) { } static int client_send_request(sd_dhcp_client *client) { - _cleanup_free_ DHCPPacket *request; - size_t optlen, len; - uint8_t *opt; + _cleanup_free_ DHCPPacket *request = NULL; + size_t optoffset, optlen; int r; - optlen = DHCP_MIN_OPTIONS_SIZE; - len = sizeof(DHCPPacket) + optlen; - - request = malloc0(len); - if (!request) - return -ENOMEM; - - r = client_message_init(client, &request->dhcp, DHCP_REQUEST, &opt, - &optlen); + r = client_message_init(client, &request, DHCP_REQUEST, + &optlen, &optoffset); if (r < 0) return r; @@ -428,13 +433,13 @@ static int client_send_request(sd_dhcp_client *client) { filled in with the yiaddr value from the chosen DHCPOFFER. */ - r = dhcp_option_append(&opt, &optlen, + r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, DHCP_OPTION_SERVER_IDENTIFIER, 4, &client->lease->server_address); if (r < 0) return r; - r = dhcp_option_append(&opt, &optlen, + r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, DHCP_OPTION_REQUESTED_IP_ADDRESS, 4, &client->lease->address); if (r < 0) @@ -447,7 +452,7 @@ static int client_send_request(sd_dhcp_client *client) { option MUST be filled in with client’s notion of its previously assigned address. ’ciaddr’ MUST be zero. */ - r = dhcp_option_append(&opt, &optlen, + r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, DHCP_OPTION_REQUESTED_IP_ADDRESS, 4, &client->last_addr); if (r < 0) @@ -480,7 +485,8 @@ static int client_send_request(sd_dhcp_client *client) { return -EINVAL; } - r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL); + r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, + DHCP_OPTION_END, 0, NULL); if (r < 0) return r; @@ -489,9 +495,9 @@ static int client_send_request(sd_dhcp_client *client) { client->lease->server_address, DHCP_PORT_SERVER, &request->dhcp, - len - optlen - DHCP_IP_UDP_SIZE); + sizeof(DHCPMessage) + optoffset); } else { - r = dhcp_client_send_raw(client, request, len - optlen); + r = dhcp_client_send_raw(client, request, sizeof(DHCPPacket) + optoffset); } if (r < 0) return r; @@ -1189,8 +1195,12 @@ static int client_receive_message_udp(sd_event_source *s, int fd, assert(client); r = ioctl(fd, FIONREAD, &buflen); - if (r < 0 || buflen <= 0) - buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE; + if (r < 0) + return r; + + if (buflen < 0) + /* this can't be right */ + return -EIO; message = malloc0(buflen); if (!message) @@ -1199,7 +1209,7 @@ static int client_receive_message_udp(sd_event_source *s, int fd, len = read(fd, message, buflen); if (len < 0) { log_dhcp_client(client, "could not receive message from UDP " - "socket: %s", strerror(errno)); + "socket: %m"); return 0; } else if ((size_t)len < sizeof(DHCPMessage)) return 0; @@ -1227,8 +1237,12 @@ static int client_receive_message_raw(sd_event_source *s, int fd, assert(client); r = ioctl(fd, FIONREAD, &buflen); - if (r < 0 || buflen <= 0) - buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE; + if (r < 0) + return r; + + if (buflen < 0) + /* this can't be right */ + return -EIO; packet = malloc0(buflen); if (!packet) @@ -1240,7 +1254,7 @@ static int client_receive_message_raw(sd_event_source *s, int fd, len = recvmsg(fd, &msg, 0); if (len < 0) { log_dhcp_client(client, "could not receive message from raw " - "socket: %s", strerror(errno)); + "socket: %m"); return 0; } else if ((size_t)len < sizeof(DHCPPacket)) return 0;