X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Flibsystemd-dhcp%2Fsd-dhcp-client.c;h=3b4db1d96ff4f72d783c9630441c422eb60e4265;hb=c6f7b693fedfd822febc219868fc810c32d458c5;hp=72998bc6cb00fab64124d6bcd7e9361d2055e8e2;hpb=a6cc569e33a05b07550c6c7b4d67d83d868f8bc1;p=elogind.git diff --git a/src/libsystemd-dhcp/sd-dhcp-client.c b/src/libsystemd-dhcp/sd-dhcp-client.c index 72998bc6c..3b4db1d96 100644 --- a/src/libsystemd-dhcp/sd-dhcp-client.c +++ b/src/libsystemd-dhcp/sd-dhcp-client.c @@ -198,118 +198,54 @@ static int client_stop(sd_dhcp_client *client, int error) { 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; - be16_t max_size; - - *opt = (uint8_t *)(message + 1); - - if (*optlen < 4) - return -ENOBUFS; - *optlen -= 4; +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; - message->op = BOOTREQUEST; - message->htype = 1; - message->hlen = ETHER_ADDR_LEN; - message->xid = htobe32(client->xid); + r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, + secs, 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; - 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; + 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) { - err = dhcp_option_append(opt, optlen, - DHCP_OPTION_PARAMETER_REQUEST_LIST, - client->req_opts_size, - client->req_opts); - if (err < 0) - return err; + 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_CLIENT_MIN_OPTIONS_SIZE); - err = dhcp_option_append(opt, optlen, - DHCP_OPTION_MAXIMUM_MESSAGE_SIZE, - 2, &max_size); - if (err < 0) - return err; + r = dhcp_option_append(opt, optlen, + DHCP_OPTION_MAXIMUM_MESSAGE_SIZE, + 2, &max_size); + if (r < 0) + return r; } 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 - 1]; - } - - while (sum >> 16) - sum = (sum & 0xffff) + (sum >> 16); - - return ~sum; -} - -static void client_append_ip_headers(DHCPPacket *packet, uint16_t len) { - packet->ip.version = IPVERSION; - packet->ip.ihl = DHCP_IP_SIZE / 4; - packet->ip.tot_len = htobe16(len); - - packet->ip.protocol = IPPROTO_UDP; - packet->ip.saddr = INADDR_ANY; - packet->ip.daddr = INADDR_BROADCAST; - - packet->udp.source = htobe16(DHCP_PORT_CLIENT); - packet->udp.dest = htobe16(DHCP_PORT_SERVER); - packet->udp.len = htobe16(len - DHCP_IP_SIZE); - - packet->ip.check = packet->udp.len; - packet->udp.check = client_checksum(&packet->ip.ttl, len - 8); - - packet->ip.ttl = IPDEFTTL; - packet->ip.check = 0; - packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE); -} - static int client_send_discover(sd_dhcp_client *client, uint16_t secs) { int err = 0; _cleanup_free_ DHCPPacket *discover; @@ -324,8 +260,8 @@ static int client_send_discover(sd_dhcp_client *client, uint16_t secs) { if (!discover) return -ENOMEM; - err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp, - secs, &opt, &optlen); + err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER, + secs, &opt, &optlen); if (err < 0) return err; @@ -341,7 +277,7 @@ static int client_send_discover(sd_dhcp_client *client, uint16_t secs) { if (err < 0) return err; - client_append_ip_headers(discover, len); + dhcp_packet_append_ip_headers(discover, BOOTREQUEST, len); err = dhcp_network_send_raw_socket(client->fd, &client->link, discover, len); @@ -362,8 +298,8 @@ static int client_send_request(sd_dhcp_client *client, uint16_t secs) { if (!request) return -ENOMEM; - err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs, - &opt, &optlen); + err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs, + &opt, &optlen); if (err < 0) return err; @@ -391,7 +327,7 @@ static int client_send_request(sd_dhcp_client *client, uint16_t secs) { &request->dhcp, len - DHCP_IP_UDP_SIZE); } else { - client_append_ip_headers(request, len); + dhcp_packet_append_ip_headers(request, BOOTREQUEST, len); err = dhcp_network_send_raw_socket(client->fd, &client->link, request, len); @@ -402,7 +338,7 @@ static int client_send_request(sd_dhcp_client *client, uint16_t secs) { static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now) { - client->secs = (time_now - client->start_time) / USEC_PER_SEC; + client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1; return client->secs; } @@ -606,34 +542,11 @@ static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message, size_t len) { - size_t hdrlen; - - if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE)) - return -EINVAL; - - hdrlen = message->ip.ihl * 4; - if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip, - hdrlen)) - return -EINVAL; - - if (hdrlen + be16toh(message->udp.len) > len) - return -EINVAL; - - if (message->udp.check) { - message->ip.check = message->udp.len; - message->ip.ttl = 0; - - if (client_checksum(&message->ip.ttl, - be16toh(message->udp.len) + 12)) - return -EINVAL; - } - - if (be16toh(message->udp.source) != DHCP_PORT_SERVER || - be16toh(message->udp.dest) != DHCP_PORT_CLIENT) - return -EINVAL; + int r; - if (message->dhcp.op != BOOTREPLY) - return -EINVAL; + r = dhcp_packet_verify_headers(message, BOOTREPLY, len); + if (r < 0) + return r; if (be32toh(message->dhcp.xid) != client->xid) return -EINVAL;