diff options
Diffstat (limited to 'src/libsystemd-network')
| -rw-r--r-- | src/libsystemd-network/sd-dhcp-client.c | 90 |
1 files changed, 72 insertions, 18 deletions
diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index e690f6785f..0adcf1328f 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -261,12 +261,12 @@ 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, @@ -274,6 +274,15 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, 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, @@ -281,9 +290,14 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, 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 */ + /* 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, @@ -312,6 +326,10 @@ 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) @@ -334,6 +352,12 @@ 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, @@ -346,6 +370,10 @@ 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; @@ -374,38 +402,64 @@ 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; } |