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TS-4688 handle DNS compression labels in SRV responses #812

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Merged
jacksontj merged 1 commit into from
Jul 21, 2016
Merged

TS-4688 handle DNS compression labels in SRV responses #812

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22 changes: 11 additions & 11 deletions iocore/dns/DNS.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1514,24 +1514,24 @@ dns_process(DNSHandler *handler, HostEnt *buf, int len)
cp += dn_skipname(cp, eom);
here = cp; /* hack */
SRV *srv = &buf->srv_hosts.hosts[num_srv];
int r = ink_ns_name_ntop(srv_off + SRV_SERVER, srv->host, MAXDNAME);
if (r <= 0) {
/* FIXME: is this really an error? or just a continue; */

// expand the name
n = ink_dn_expand((u_char *)h, eom, srv_off + SRV_SERVER, (u_char *)srv->host, MAXDNAME);
if (n < 0) {
++error;
goto Lerror;
break;
}
Debug("dns_srv", "Discovered SRV record [from NS lookup] with cost:%d weight:%d port:%d with host:%s",
ink_get16(srv_off + SRV_COST), ink_get16(srv_off + SRV_WEIGHT), ink_get16(srv_off + SRV_PORT), srv->host);

srv->port = ink_get16(srv_off + SRV_PORT);
srv->priority = ink_get16(srv_off + SRV_COST);
srv->weight = ink_get16(srv_off + SRV_WEIGHT);
srv->host_len = r;
srv->host[r - 1] = '\0';
srv->key = makeHostHash(srv->host);
srv->port = ink_get16(srv_off + SRV_PORT);
srv->priority = ink_get16(srv_off + SRV_COST);
srv->weight = ink_get16(srv_off + SRV_WEIGHT);
srv->host_len = ::strlen(srv->host) + 1;
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@SolidWallOfCode SolidWallOfCode Jul 19, 2016

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n doesn't have the value you want here?

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@jacksontj jacksontj Jul 20, 2016

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Sadly no, n is the length of the compressed string, not the expanded string-- meaning I have to calculate the len of the expanded string.

srv->key = makeHostHash(srv->host);

if (srv->host[0] != '\0')
buf->srv_hosts.srv_hosts_length += r;
buf->srv_hosts.srv_hosts_length += srv->host_len;
else
continue;
++num_srv;
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