On 1/23/24 22:47, Mark Michelson wrote:
> Hi Dumitru.
> 

Hi Mark,

> Two questions:
> 
> 1) Did you mean to title this as "additional additional records?" Or did
> you just mean "additional records?"
> 

Well, no, I didn't I just expanded AR without thinking. :)

> 2) Should this include a test? I'm thinking you could construct a DNS
> query that includes an EDNS AR and ensure that OVN responds to it.
> 

I should've added a test, you're right.

I'll work on v2, thanks for checking this out!

Regards,
Dumitru

> Thanks,
> Mark Michelson
> 
> On 1/23/24 09:15, Dumitru Ceara wrote:
>> EDNS is backwards compatible so it's safe to just ignore additional ARs.
>>
>> Reported-at: https://github.com/ovn-org/ovn/issues/228
>> Reported-at: https://issues.redhat.com/browse/FDP-222
>> Signed-off-by: Dumitru Ceara <[email protected]>
>> ---
>>   controller/pinctrl.c | 20 ++++++++++----------
>>   1 file changed, 10 insertions(+), 10 deletions(-)
>>
>> diff --git a/controller/pinctrl.c b/controller/pinctrl.c
>> index 4992eab089..0be77701ec 100644
>> --- a/controller/pinctrl.c
>> +++ b/controller/pinctrl.c
>> @@ -2885,6 +2885,7 @@ dns_build_ptr_answer(
>>       free(encoded);
>>   }
>>   +#define DNS_QUERY_TYPE_CLASS_LEN (2 * sizeof(ovs_be16))
>>   #define DNS_RCODE_SERVER_REFUSE 0x5
>>     /* Called with in the pinctrl_handler thread context. */
>> @@ -2949,18 +2950,13 @@ pinctrl_handle_dns_lookup(
>>           goto exit;
>>       }
>>   -    /* Check if there is an additional record present, which is
>> unsupported */
>> -    if (in_dns_header->arcount) {
>> -        VLOG_DBG_RL(&rl, "Received DNS query with additional records,
>> which"
>> -                    " is unsupported");
>> -        goto exit;
>> -    }
>> -
>>       struct udp_header *in_udp = dp_packet_l4(pkt_in);
>>       size_t udp_len = ntohs(in_udp->udp_len);
>>       size_t l4_len = dp_packet_l4_size(pkt_in);
>> +    uint8_t *l4_start = (uint8_t *) in_udp;
>>       uint8_t *end = (uint8_t *)in_udp + MIN(udp_len, l4_len);
>>       uint8_t *in_dns_data = (uint8_t *)(in_dns_header + 1);
>> +    uint8_t *in_dns_data_start = in_dns_data;
>>       uint8_t *in_queryname = in_dns_data;
>>       uint16_t idx = 0;
>>       struct ds query_name;
>> @@ -2984,7 +2980,7 @@ pinctrl_handle_dns_lookup(
>>       in_dns_data += idx;
>>         /* Query should have TYPE and CLASS fields */
>> -    if (in_dns_data + (2 * sizeof(ovs_be16)) > end) {
>> +    if (in_dns_data + DNS_QUERY_TYPE_CLASS_LEN > end) {
>>           ds_destroy(&query_name);
>>           goto exit;
>>       }
>> @@ -2998,6 +2994,10 @@ pinctrl_handle_dns_lookup(
>>           goto exit;
>>       }
>>   +    uint8_t *rest = in_dns_data + DNS_QUERY_TYPE_CLASS_LEN;
>> +    uint32_t query_size = rest - in_dns_data_start;
>> +    uint32_t query_l4_size = rest - l4_start;
>> +
>>       uint64_t dp_key = ntohll(pin->flow_metadata.flow.metadata);
>>       const char *answer_data = NULL;
>>       bool ovn_owned = false;
>> @@ -3080,7 +3080,7 @@ pinctrl_handle_dns_lookup(
>>           goto exit;
>>       }
>>   -    uint16_t new_l4_size = ntohs(in_udp->udp_len) +  dns_answer.size;
>> +    uint16_t new_l4_size = query_l4_size + dns_answer.size;
>>       size_t new_packet_size = pkt_in->l4_ofs + new_l4_size;
>>       struct dp_packet pkt_out;
>>       dp_packet_init(&pkt_out, new_packet_size);
>> @@ -3117,7 +3117,7 @@ pinctrl_handle_dns_lookup(
>>       out_dns_header->arcount = 0;
>>         /* Copy the Query section. */
>> -    dp_packet_put(&pkt_out, dp_packet_data(pkt_in),
>> dp_packet_size(pkt_in));
>> +    dp_packet_put(&pkt_out, dp_packet_data(pkt_in), query_size);
>>         /* Copy the answer sections. */
>>       dp_packet_put(&pkt_out, dns_answer.data, dns_answer.size);
> 

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