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udhcpc6: add some comments

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RFCs for DHCPv6 are written rather badly...

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2022-12-14 00:36:59 +01:00
parent 9898db4c94
commit e977853e70
2 changed files with 39 additions and 12 deletions
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41
networking/udhcp/d6_common.h
View File

@ -63,28 +63,45 @@ struct d6_option {
#define D6_OPT_CLIENTID 1
#define D6_OPT_SERVERID 2
/* "Identity Association for Non-temporary Addresses",
* also known as a "network interface" in plain English */
#define D6_OPT_IA_NA 3
#define D6_OPT_IA_TA 4
/* "Identity Association for the Temporary Addresses".
* Presumably this is a "network interface with only link-local addresses".
* Why would DHCPv6 server assign such addresses, I have no idea. */
//#define D6_OPT_IA_TA 4
/* "IA Address", an IPv6 address */
#define D6_OPT_IAADDR 5
/* Option "Option Request Option". From the owners of a doggy dog named Dog? */
#define D6_OPT_ORO 6
#define D6_OPT_PREFERENCE 7
//#define D6_OPT_PREFERENCE 7
#define D6_OPT_ELAPSED_TIME 8
#define D6_OPT_RELAY_MSG 9
#define D6_OPT_AUTH 11
#define D6_OPT_UNICAST 12
//#define D6_OPT_RELAY_MSG 9
//#define D6_OPT_AUTH 11
/* "The server sends this option to a client to indicate to the client
* that it is allowed to unicast messages to the server."
* Contains IPv6 address to send packets to. */
//#define D6_OPT_UNICAST 12
/* "A Status Code option may appear in the options field of a DHCP
* message and/or in the options field of another option." */
#define D6_OPT_STATUS_CODE 13
#define D6_OPT_RAPID_COMMIT 14
#define D6_OPT_USER_CLASS 15
#define D6_OPT_VENDOR_CLASS 16
#define D6_OPT_VENDOR_OPTS 17
#define D6_OPT_INTERFACE_ID 18
#define D6_OPT_RECONF_MSG 19
#define D6_OPT_RECONF_ACCEPT 20
/* "A client MAY include this option in a Solicit message if the client
* is prepared to perform the Solicit-Reply message exchange..." */
//#define D6_OPT_RAPID_COMMIT 14 /* zero-length option */
//#define D6_OPT_USER_CLASS 15
//#define D6_OPT_VENDOR_CLASS 16
//#define D6_OPT_VENDOR_OPTS 17
//#define D6_OPT_INTERFACE_ID 18
//#define D6_OPT_RECONF_MSG 19
//#define D6_OPT_RECONF_ACCEPT 20
#define D6_OPT_DNS_SERVERS 23
#define D6_OPT_DOMAIN_LIST 24
/* RFC 3633 "Identity Association for Prefix Delegation".
* This option says that client wants to get an IPv6 prefix */
#define D6_OPT_IA_PD 25
/* Response from the server comes in this one */
#define D6_OPT_IAPREFIX 26
/* RFC 4704 "The DHCPv6 Client FQDN Option"

10
networking/udhcp/d6_dhcpc.c
View File

@ -1617,6 +1617,16 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
prefix_timeout = 0;
option = d6_find_option(packet.d6_options, packet_end, D6_OPT_STATUS_CODE);
if (option && (option->data[0] | option->data[1]) != 0) {
///FIXME:
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | OPTION_STATUS_CODE | option-len |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | status-code | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
// . status-message .
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// so why do we think it's NAK if data[0] is zero but data[1] is not? That's wrong...
// we should also check that option->len is ok (i.e. not 0), right?
/* return to init state */
bb_info_msg("received DHCP NAK (%u)", option->data[4]);
d6_run_script(packet.d6_options,