Re: [Dnsmasq-discuss] [PATCH] Fix dns query retransmission when --strict-order active
On Tue, Dec 5, 2017 at 11:41 PM, Simon Kelley wrote:
> OK, I re-worked this and committed it as
>
> http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=ef3d137a646fa8309e1ff5184e3e145eef40cc4d
>
> Please could you check I didn't break anything?
Testing with the patch did not show any regression; looks fine for me
Hans
>
>
> Cheers,
>
> Simon.
>
>
> On 04/12/17 09:15, Hans Dedecker wrote:
>> Commit 9396752c115b3ab733fa476b30da73237e12e7ba added support for dns query
>> retransmission in case a server returns refused in strict-order mode.
>> The patch did not cover the case when all servers return refused triggering
>> a dns query retransmission storm resulting into a high cpu load by dnsmasq.
>> Fix the problem by checking in strict-order mode if a next dns server is
>> available in the dns server list before forwarding the query again.
>>
>> Signed-off-by: Hans Dedecker
>> ---
>> src/forward.c | 18 +++---
>> 1 file changed, 15 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/forward.c b/src/forward.c
>> index 4824759..3d58571 100644
>> --- a/src/forward.c
>> +++ b/src/forward.c
>> @@ -799,11 +799,23 @@ void reply_query(int fd, int family, time_t now)
>> {
>>unsigned char *pheader;
>>size_t plen;
>> - int is_sign;
>> -
>> + int is_sign, fwd_query = 0;
>> +
>> + if (option_bool(OPT_ORDER))
>> +{
>> + /* try to find a good server to which the query can be forwarded */
>> + for (server = forward->sentto->next; server; server = server->next)
>> + if (!(server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN |
>> SERV_FOR_NODOTS | SERV_NO_ADDR | SERV_LOOP)))
>> + {
>> +fwd_query = 1;
>> +break;
>> + }
>> +} else
>> + fwd_query = 1;
>> +
>>/* recreate query from reply */
>>pheader = find_pseudoheader(header, (size_t)n, &plen, NULL, &is_sign,
>> NULL);
>> - if (!is_sign)
>> + if (!is_sign && fwd_query)
>> {
>> header->ancount = htons(0);
>> header->nscount = htons(0);
>>
>
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Re: [Dnsmasq-discuss] [PATCH] Fix dns query retransmission when --strict-order active
OK, I re-worked this and committed it as
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=ef3d137a646fa8309e1ff5184e3e145eef40cc4d
Please could you check I didn't break anything?
Cheers,
Simon.
On 04/12/17 09:15, Hans Dedecker wrote:
> Commit 9396752c115b3ab733fa476b30da73237e12e7ba added support for dns query
> retransmission in case a server returns refused in strict-order mode.
> The patch did not cover the case when all servers return refused triggering
> a dns query retransmission storm resulting into a high cpu load by dnsmasq.
> Fix the problem by checking in strict-order mode if a next dns server is
> available in the dns server list before forwarding the query again.
>
> Signed-off-by: Hans Dedecker
> ---
> src/forward.c | 18 +++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/src/forward.c b/src/forward.c
> index 4824759..3d58571 100644
> --- a/src/forward.c
> +++ b/src/forward.c
> @@ -799,11 +799,23 @@ void reply_query(int fd, int family, time_t now)
> {
>unsigned char *pheader;
>size_t plen;
> - int is_sign;
> -
> + int is_sign, fwd_query = 0;
> +
> + if (option_bool(OPT_ORDER))
> +{
> + /* try to find a good server to which the query can be forwarded */
> + for (server = forward->sentto->next; server; server = server->next)
> + if (!(server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN |
> SERV_FOR_NODOTS | SERV_NO_ADDR | SERV_LOOP)))
> + {
> +fwd_query = 1;
> +break;
> + }
> +} else
> + fwd_query = 1;
> +
>/* recreate query from reply */
>pheader = find_pseudoheader(header, (size_t)n, &plen, NULL, &is_sign,
> NULL);
> - if (!is_sign)
> + if (!is_sign && fwd_query)
> {
> header->ancount = htons(0);
> header->nscount = htons(0);
>
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