MINOR: dns: make 'ancount' field to match the number of saved records

ancount is the number of answers available in a DNS response.
Before this patch, HAProxy used to store the ancount found in the buffer
(sent by the DNS server).
Unfortunately, this is now inaccurate and does not correspond to the
number of records effectively stored in our local version of the
response. In Example, the CNAMEs are not stored.

This patch updates ancount field in to make it match what is effectively
stored in our version.

diff --git a/src/dns.c b/src/dns.c
index 45444fdb3e44593572ae75744b3d3dd6c9b1d2b6..0193f7396f77ff8e657fc5d5326294d78dbdeb79 100644 (file)
--- a/src/dns.c
+++ b/src/dns.c
@@ -467,6 +467,7 @@ int dns_validate_dns_response(unsigned char *resp, unsigned char *bufend, struct
        char *previous_dname, tmpname[DNS_MAX_NAME_SIZE];
        int len, flags, offset, ret;
        int dns_query_record_id, dns_answer_record_id;
+       int nb_saved_records;
        struct dns_query_item *dns_query;
        struct dns_answer_item *dns_answer_record;
        struct dns_response_packet *dns_p;
@@ -591,6 +592,7 @@ int dns_validate_dns_response(unsigned char *resp, unsigned char *bufend, struct
 
        /* now parsing response records */
        LIST_INIT(&dns_p->answer_list);
+       nb_saved_records = 0;
        for (dns_answer_record_id = 0; dns_answer_record_id < dns_p->header.ancount; dns_answer_record_id++) {
                if (reader >= bufend)
                        return DNS_RESP_INVALID;
@@ -717,6 +719,9 @@ int dns_validate_dns_response(unsigned char *resp, unsigned char *bufend, struct
 
                } /* switch (record type) */
 
+               /* increment the counter for number of records saved into our local response */
+               nb_saved_records += 1;
+
                /* move forward dns_answer_record->data_len for analyzing next record in the response */
                reader += dns_answer_record->data_len;
        } /* for i 0 to ancount */
@@ -726,6 +731,9 @@ int dns_validate_dns_response(unsigned char *resp, unsigned char *bufend, struct
        if (ret == 0)
                return DNS_RESP_INVALID;
 
+       /* save the number of records we really own */
+       dns_p->header.ancount = nb_saved_records;
+
        return DNS_RESP_VALID;
 }