[Dnsmasq-discuss] [PATCH] Add DHCP6REPLY for DHCP6REBIND

[Simon Kelley]

On 09/04/2021 08:30, liaichun wrote:
>> On Apr 8, 2021, at 16:01, Simon Kelley <si... at thekelleys.org.uk> wrote:
>>> Before this, we receive a DHCP6REBIND request and do not reply.
>>> We should increase the number of responses to such packets.
>>>
>>
>> Not good to have omitted this for so long. Thanks for the patch.
>>
>> Since most of the code is the same for DHCPRENEW and DHCPREBIND, I
>> prefer to share it. Also,  reading RFC8415 18.3.5, if no lease exists or
>> can be created for any of the IAs, there should be an error status of no
>> addresses available in the reply.
>>
>> The attached patch make these changes. Please could you check that it
>> works OK for you?
> 
> Yes, It's ok. Thank you for your reply.
> 

Great. Patch committed.

https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=d55e2d086d1ff30c427fa5e0ecc79746de8a81b7


Cheers,

Simon.



> Cheers,
> 
> Aichun Li
> 
> 
>>
>>
>> Cheers,
>>
>> Simon.
>>
>> diff --git a/src/rfc3315.c b/src/rfc3315.c
>> index 982c68a..5c2ff97 100644
>> --- a/src/rfc3315.c
>> +++ b/src/rfc3315.c
>> @@ -919,11 +919,14 @@ static int dhcp6_no_relay(struct state *state, int 
>> msg_type, void *inbuff, size_
>>       
>>   
>>     case DHCP6RENEW:
>> +    case DHCP6REBIND:
>>       {
>> +       int address_assigned = 0;
>> +
>>        /* set reply message type */
>>        *outmsgtypep = DHCP6REPLY;
>>        
>> -       log6_quiet(state, "DHCPRENEW", NULL, NULL);
>> +       log6_quiet(state, msg_type == DHCP6RENEW ? "DHCPRENEW" : "DHCPREBIND", 
>> NULL, NULL);
>>
>>        for (opt = state->packet_options; opt; opt = opt6_next(opt, state->end))
>>          {
>> @@ -952,24 +955,35 @@ static int dhcp6_no_relay(struct state *state, int 
>> msg_type, void *inbuff, size_
>>                                          state->ia_type == OPTION6_IA_NA ? 
>> LEASE_NA : LEASE_TA, 
>>                                          state->iaid, &req_addr)))
>>                  {
>> -                   /* If the server cannot find a client entry for the IA the 
>> server
>> -                      returns the IA containing no addresses with a Status 
>> Code option set
>> -                      to NoBinding in the Reply message. */
>> -                   save_counter(iacntr);
>> -                   t1cntr = 0;
>> -                   
>> -                   log6_packet(state, "DHCPREPLY", &req_addr, _("lease not 
>> found"));
>> -                   
>> -                   o1 = new_opt6(OPTION6_STATUS_CODE);
>> -                   put_opt6_short(DHCP6NOBINDING);
>> -                   put_opt6_string(_("no binding found"));
>> -                   end_opt6(o1);
>> -
>> -                   preferred_time = valid_time = 0;
>> -                   break;
>> +                   if (msg_type == DHCP6REBIND)
>> +                     {
>> +                       /* When rebinding, we can create a lease if it doesn't 
>> exist. */
>> +                       lease = lease6_allocate(&req_addr, state->ia_type == 
>> OPTION6_IA_NA ? LEASE_NA : LEASE_TA);
>> +                       if (lease)
>> +                         lease_set_iaid(lease, state->iaid);
>> +                       else
>> +                         break;
>> +                     }
>> +                   else
>> +                     {
>> +                       /* If the server cannot find a client entry for the IA 
>> the server
>> +                          returns the IA containing no addresses with a Status 
>> Code option set
>> +                          to NoBinding in the Reply message. */
>> +                       save_counter(iacntr);
>> +                       t1cntr = 0;
>> +                       
>> +                       log6_packet(state, "DHCPREPLY", &req_addr, _("lease not 
>> found"));
>> +                       
>> +                       o1 = new_opt6(OPTION6_STATUS_CODE);
>> +                       put_opt6_short(DHCP6NOBINDING);
>> +                       put_opt6_string(_("no binding found"));
>> +                       end_opt6(o1);
>> +                       
>> +                       preferred_time = valid_time = 0;
>> +                       break;
>> +                     }
>>                  }
>>                
>> -               
>>                if ((this_context = address6_available(state->context, 
>> &req_addr, tagif, 1)) ||
>>                    (this_context = address6_valid(state->context, &req_addr, 
>> tagif, 1)))
>>                  {
>> @@ -1000,6 +1014,8 @@ static int dhcp6_no_relay(struct state *state, int 
>> msg_type, void *inbuff, size_
>>                    
>>                    if (preferred_time == 0)
>>                      message = _("deprecated");
>> +
>> +                   address_assigned = 1;
>>                  }
>>                else
>>                  {
>> @@ -1022,10 +1038,18 @@ static int dhcp6_no_relay(struct state *state, int 
>> msg_type, void *inbuff, size_
>>            end_ia(t1cntr, min_time, 1);
>>            end_opt6(o);
>>          }
>> +
>> +       if (!address_assigned && msg_type == DHCP6REBIND)
>> +         { 
>> +           /* can't create lease for any address, return error */
>> +           o1 = new_opt6(OPTION6_STATUS_CODE);
>> +           put_opt6_short(DHCP6NOADDRS);
>> +           put_opt6_string(_("no addresses available"));
>> +           end_opt6(o1);
>> +         }
>>        
>>        tagif = add_options(state, 0);
>>        break;
>> -       
>>       }
>>       
>>     case DHCP6CONFIRM:
>