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udhcpc: emit maxsize option in all non-NAK type packets

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Before, we were sending them only in DISCOVER packets.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-10-20 21:37:23 +02:00
parent 2c3b71a0d2
commit b3af65b95d
1 changed files with 92 additions and 20 deletions
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112
networking/udhcp/dhcpc.c
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@ -346,31 +346,34 @@ static ALWAYS_INLINE uint32_t random_xid(void)
/* Initialize the packet with the proper defaults */
static void init_packet(struct dhcp_packet *packet, char type)
{
/* Fill in: op, htype, hlen, cookie fields; message type option: */
udhcp_init_header(packet, type);
packet->xid = random_xid();
memcpy(packet->chaddr, client_config.client_mac, 6);
if (client_config.clientid)
udhcp_add_binary_option(packet, client_config.clientid);
if (client_config.hostname)
udhcp_add_binary_option(packet, client_config.hostname);
if (client_config.fqdn)
udhcp_add_binary_option(packet, client_config.fqdn);
if (type != DHCPDECLINE
&& type != DHCPRELEASE
&& client_config.vendorclass
) {
udhcp_add_binary_option(packet, client_config.vendorclass);
}
}
static void add_client_options(struct dhcp_packet *packet)
{
uint8_t c;
int i, end, len;
udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
if (client_config.hostname)
udhcp_add_binary_option(packet, client_config.hostname);
if (client_config.fqdn)
udhcp_add_binary_option(packet, client_config.fqdn);
if (client_config.vendorclass)
udhcp_add_binary_option(packet, client_config.vendorclass);
/* Add a "param req" option with the list of options we'd like to have
* from stubborn DHCP servers. Pull the data from the struct in common.c.
* No bounds checking because it goes towards the head of the packet. */
uint8_t c;
int end = udhcp_end_option(packet->options);
int i, len = 0;
end = udhcp_end_option(packet->options);
len = 0;
for (i = 0; (c = dhcp_optflags[i].code) != 0; i++) {
if (( (dhcp_optflags[i].flags & OPTION_REQ)
&& !client_config.no_default_options
@ -432,13 +435,20 @@ static int send_discover(uint32_t xid, uint32_t requested)
{
struct dhcp_packet packet;
/* Fill in: op, htype, hlen, cookie, chaddr fields,
* random xid field (we override it below),
* client-id option (unless -C), message type option:
*/
init_packet(&packet, DHCPDISCOVER);
packet.xid = xid;
if (requested)
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
/* Explicitly saying that we want RFC-compliant packets helps
* some buggy DHCP servers to NOT send bigger packets */
udhcp_add_simple_option(&packet, DHCP_MAX_SIZE, htons(576));
/* Add options: maxsize,
* optionally: hostname, fqdn, vendorclass,
* "param req" option according to -O, options specified with -x
*/
add_client_options(&packet);
bb_info_msg("Sending discover...");
@ -454,10 +464,33 @@ static int send_select(uint32_t xid, uint32_t server, uint32_t requested)
struct dhcp_packet packet;
struct in_addr addr;
/*
* RFC 2131 4.3.2 DHCPREQUEST message
* ...
* If the DHCPREQUEST message contains a 'server identifier'
* option, the message is in response to a DHCPOFFER message.
* Otherwise, the message is a request to verify or extend an
* existing lease. If the client uses a 'client identifier'
* in a DHCPREQUEST message, it MUST use that same 'client identifier'
* in all subsequent messages. If the client included a list
* of requested parameters in a DHCPDISCOVER message, it MUST
* include that list in all subsequent messages.
*/
/* Fill in: op, htype, hlen, cookie, chaddr fields,
* random xid field (we override it below),
* client-id option (unless -C), message type option:
*/
init_packet(&packet, DHCPREQUEST);
packet.xid = xid;
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
/* Add options: maxsize,
* optionally: hostname, fqdn, vendorclass,
* "param req" option according to -O, and options specified with -x
*/
add_client_options(&packet);
addr.s_addr = requested;
@ -470,9 +503,33 @@ static int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
{
struct dhcp_packet packet;
/*
* RFC 2131 4.3.2 DHCPREQUEST message
* ...
* DHCPREQUEST generated during RENEWING state:
*
* '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. In this situation, the client is completely
* configured, and is trying to extend its lease. This message will
* be unicast, so no relay agents will be involved in its
* transmission. Because 'giaddr' is therefore not filled in, the
* DHCP server will trust the value in 'ciaddr', and use it when
* replying to the client.
*/
/* Fill in: op, htype, hlen, cookie, chaddr fields,
* random xid field (we override it below),
* client-id option (unless -C), message type option:
*/
init_packet(&packet, DHCPREQUEST);
packet.xid = xid;
packet.ciaddr = ciaddr;
/* Add options: maxsize,
* optionally: hostname, fqdn, vendorclass,
* "param req" option according to -O, and options specified with -x
*/
add_client_options(&packet);
bb_info_msg("Sending renew...");
@ -489,9 +546,20 @@ static int send_decline(uint32_t xid, uint32_t server, uint32_t requested)
{
struct dhcp_packet packet;
/* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
* client-id option (unless -C), message type option:
*/
init_packet(&packet, DHCPDECLINE);
/* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
* but in case the server is buggy and wants DHCPDECLINE's xid
* to match the xid which started entire handshake,
* we use the same xid we used in initial DHCPDISCOVER:
*/
packet.xid = xid;
/* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
bb_info_msg("Sending decline...");
@ -504,8 +572,12 @@ static int send_release(uint32_t server, uint32_t ciaddr)
{
struct dhcp_packet packet;
/* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
* client-id option (unless -C), message type option:
*/
init_packet(&packet, DHCPRELEASE);
packet.xid = random_xid();
/* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
packet.ciaddr = ciaddr;
udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
@ -1254,7 +1326,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
/* Ignore packets that aren't for us */
if (packet.hlen != 6
|| memcmp(packet.chaddr, client_config.client_mac, 6)
|| memcmp(packet.chaddr, client_config.client_mac, 6) != 0
) {
//FIXME: need to also check that last 10 bytes are zero
log1("chaddr does not match, ignoring packet"); // log2?
@ -1280,7 +1352,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
}
/* it IS unaligned sometimes, don't "optimize" */
move_from_unaligned32(server_addr, temp);
xid = packet.xid;
/*xid = packet.xid; - already is */
requested_ip = packet.yiaddr;
/* enter requesting state */