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net: dns: Support multiple simultaneous mDNS requests

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As mDNS requests set DNS id to 0, we cannot use it to match
the DNS response packet. In order to allow this functionality,
create a hash from query name and type, and use that together
with DNS id to match request and response.

Fixes #21914

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
This commit is contained in:
Jukka Rissanen 2020-01-15 16:30:07 +02:00
commit f9c18dd962
2 changed files with 209 additions and 68 deletions
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25
include/net/dns_resolve.h
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@ -208,6 +208,14 @@ struct dns_resolve_context {
/** DNS id of this query */
u16_t id;
/** Hash of the DNS name + query type we are querying.
* This hash is calculated so we can match the response that
* we are receiving. This is needed mainly for mDNS which is
* setting the DNS id to 0, which means that the id alone
* cannot be used to find correct pending query.
*/
u16_t query_hash;
} queries[CONFIG_DNS_NUM_CONCUR_QUERIES];
/** Is this context in use */
@ -270,6 +278,23 @@ int dns_resolve_close(struct dns_resolve_context *ctx);
int dns_resolve_cancel(struct dns_resolve_context *ctx,
u16_t dns_id);
/**
* @brief Cancel a pending DNS query using id, name and type.
*
* @details This releases DNS resources used by a pending query.
*
* @param ctx DNS context
* @param dns_id DNS id of the pending query
* @param query_name Name of the resource we are trying to query (hostname)
* @param query_type Type of the query (A or AAAA)
*
* @return 0 if ok, <0 if error.
*/
int dns_resolve_cancel_with_name(struct dns_resolve_context *ctx,
u16_t dns_id,
const char *query_name,
enum dns_query_type query_type);
/**
* @brief Resolve DNS name.
*