Generalizing curves to groups in preparation for TLS 1.3.

The 'elliptic_curves' extension is being renamed to 'supported_groups'
in the TLS 1.3 draft, and most of the curve-specific methods are
generalized to groups/group IDs.

Change-Id: Icd1a1cf7365c8a4a64ae601993dc4273802610fb
Reviewed-on: https://boringssl-review.googlesource.com/7955
Reviewed-by: David Benjamin <davidben@google.com>

ssl/s3_clnt.c

diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 39aea3c..51274f7 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -1137,26 +1137,26 @@
     ssl->s3->tmp.peer_key_len = (uint16_t)peer_key_len;
   } else if (alg_k & SSL_kECDHE) {
     /* Parse the server parameters. */
-    uint8_t curve_type;
-    uint16_t curve_id;
+    uint8_t group_type;
+    uint16_t group_id;
     CBS point;
-    if (!CBS_get_u8(&server_key_exchange, &curve_type) ||
-        curve_type != NAMED_CURVE_TYPE ||
-        !CBS_get_u16(&server_key_exchange, &curve_id)) {
+    if (!CBS_get_u8(&server_key_exchange, &group_type) ||
+        group_type != NAMED_CURVE_TYPE ||
+        !CBS_get_u16(&server_key_exchange, &group_id)) {
       al = SSL_AD_DECODE_ERROR;
       OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
       goto f_err;
     }
-    ssl->session->key_exchange_info = curve_id;
+    ssl->session->key_exchange_info = group_id;
 
-    /* Ensure the curve is consistent with preferences. */
-    if (!tls1_check_curve_id(ssl, curve_id)) {
+    /* Ensure the group is consistent with preferences. */
+    if (!tls1_check_group_id(ssl, group_id)) {
       al = SSL_AD_ILLEGAL_PARAMETER;
       OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
       goto f_err;
     }
 
-    if (!SSL_ECDH_CTX_init(&ssl->s3->tmp.ecdh_ctx, curve_id)) {
+    if (!SSL_ECDH_CTX_init(&ssl->s3->tmp.ecdh_ctx, group_id)) {
       goto err;
     }
     if (!SSL_ECDH_CTX_get_key(&ssl->s3->tmp.ecdh_ctx, &server_key_exchange,