best effort tls enabled if env DRACHTIO_SUPPORT_BEST_EFFORT_TLS=1, me…

…aning if remote side sends over tls with contact of sip rather than sip we will respond in kind with our contact header (#327)

src/sip-dialog-controller.cpp

@@ -21,6 +21,7 @@ THE SOFTWARE.
 */
 #include <algorithm>
 #include <regex>
+#include <cstdlib> // For std::getenv
 
 #include <boost/algorithm/string.hpp>
 #include <boost/algorithm/string/find.hpp>
@@ -41,6 +42,8 @@ namespace drachtio {
 
 namespace {
 
+    const char* envSupportBestEffortTls = std::getenv("DRACHTIO_SUPPORT_BEST_EFFORT_TLS");
+
     std::string combineCallIdAndCSeq(nta_outgoing_t* orq) {
         string callIdAndCSeq = nta_outgoing_call_id(orq);
         callIdAndCSeq.append(" ");
@@ -1122,6 +1125,15 @@ namespace drachtio {
                     assert(pSelectedTransport); 
 
                     pSelectedTransport->getContactUri(contact, true);
+
+                    /* is far end requesting "best effort" tls ?*/
+                    if (envSupportBestEffortTls && atoi(envSupportBestEffortTls) == 1 &&
+                      pSelectedTransport->isSips() && sip->sip_contact && sip->sip_contact->m_url &&
+                      0 == strcmp(sip->sip_contact->m_url->url_scheme, "sip")) {
+                        contact.replace(0, 5, "sip:");
+                        DR_LOG(log_info) << "SipDialogController::doRespondToSipRequest - far end wants best effort tls, replacing sips with sip in Contact";
+                    }
+
                     contact = "<" + contact + ">" ;
 
                     pSelectedTransport->getDescription(transportDesc);

src/sip-transports.hpp

@@ -70,6 +70,7 @@ namespace drachtio {
     bool isIpV6(void) ;
     bool isLocalhost(void) ;
     bool isLocal(const char* szHost) ;
+    bool isSips(void) { return 0 == m_contactScheme.compare("sips"); }
 
     void setNetwork(const string& network) { m_network = network;}
     void setNetmask(uint32_t netmask) { m_netmask = netmask;}