res_pjsip: Add the ability to configure ciphers based on name.

Previously this code would only accept the OpenSSL identifier instead
of the documented name.

ASTERISK-23498 #close
ASTERISK-23498 #comment Reported by: Anthony Messina

Review: https://reviewboard.asterisk.org/r/3491/
........

Merged revisions 413159 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@413160 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_pjsip/config_transport.c

@@ -379,6 +379,30 @@ static int tls_method_to_str(const void *obj, const intptr_t *args, char **buf)
 	return 0;
 }
 
+/*! \brief Helper function which turns a cipher name into an identifier */
+static pj_ssl_cipher cipher_name_to_id(const char *name)
+{
+	pj_ssl_cipher ciphers[100], id = 0;
+	unsigned int cipher_num = PJ_ARRAY_SIZE(ciphers);
+	int pos;
+
+	if (pj_ssl_cipher_get_availables(ciphers, &cipher_num)) {
+		return 0;
+	}
+
+	for (pos = 0; pos < cipher_num; ++pos) {
+		if (!pj_ssl_cipher_name(ciphers[pos]) ||
+			strcmp(pj_ssl_cipher_name(ciphers[pos]), name)) {
+			continue;
+		}
+
+		id = ciphers[pos];
+		break;
+	}
+
+	return id;
+}
+
 /*! \brief Custom handler for TLS cipher setting */
 static int transport_tls_cipher_handler(const struct aco_option *opt, struct ast_variable *var, void *obj)
 {
@@ -389,6 +413,9 @@ static int transport_tls_cipher_handler(const struct aco_option *opt, struct ast
 		return -1;
 	}
 
+	cipher = cipher_name_to_id(var->value);
+
+	if (!cipher) {
 		/* TODO: Check this over/tweak - it's taken from pjsua for now */
 		if (!strnicmp(var->value, "0x", 2)) {
 			pj_str_t cipher_st = pj_str((char*)var->value + 2);
@@ -396,6 +423,7 @@ static int transport_tls_cipher_handler(const struct aco_option *opt, struct ast
 		} else {
 			cipher = atoi(var->value);
 		}
+	}
 
 	if (pj_ssl_cipher_is_supported(cipher)) {
 		transport->ciphers[transport->tls.ciphers_num++] = cipher;