+
+/* By default s_server uses an in-memory cache which caches SSL_SESSION
+ * structures without any serialisation. This hides some bugs which only
+ * become apparent in deployed servers. By implementing a basic external
+ * session cache some issues can be debugged using s_server.
+ */
+
+typedef struct simple_ssl_session_st
+ {
+ unsigned char *id;
+ unsigned int idlen;
+ unsigned char *der;
+ int derlen;
+ struct simple_ssl_session_st *next;
+ } simple_ssl_session;
+
+static simple_ssl_session *first = NULL;
+
+static int add_session(SSL *ssl, SSL_SESSION *session)
+ {
+ simple_ssl_session *sess;
+ unsigned char *p;
+
+ sess = OPENSSL_malloc(sizeof(simple_ssl_session));
+
+ sess->idlen = SSL_SESSION_get_id_len(session);
+ sess->derlen = i2d_SSL_SESSION(session, NULL);
+
+ sess->id = BUF_memdup(SSL_SESSION_get0_id(session), sess->idlen);
+
+ sess->der = OPENSSL_malloc(sess->derlen);
+ p = sess->der;
+ i2d_SSL_SESSION(session, &p);
+
+ sess->next = first;
+ first = sess;
+ BIO_printf(bio_err, "New session added to external cache\n");
+ return 0;
+ }
+
+static SSL_SESSION *get_session(SSL *ssl, unsigned char *id, int idlen,
+ int *do_copy)
+ {
+ simple_ssl_session *sess;
+ *do_copy = 0;
+ for (sess = first; sess; sess = sess->next)
+ {
+ if (idlen == (int)sess->idlen && !memcmp(sess->id, id, idlen))
+ {
+ const unsigned char *p = sess->der;
+ BIO_printf(bio_err, "Lookup session: cache hit\n");
+ return d2i_SSL_SESSION(NULL, &p, sess->derlen);
+ }
+ }
+ BIO_printf(bio_err, "Lookup session: cache miss\n");
+ return NULL;
+ }
+
+static void del_session(SSL_CTX *sctx, SSL_SESSION *session)
+ {
+ simple_ssl_session *sess, *prev = NULL;
+ const unsigned char *id = SSL_SESSION_get0_id(session);
+ unsigned int idlen = SSL_SESSION_get_id_len(session);
+ for (sess = first; sess; sess = sess->next)
+ {
+ if (idlen == sess->idlen && !memcmp(sess->id, id, idlen))
+ {
+ if(prev)
+ prev->next = sess->next;
+ else
+ first = sess->next;
+ OPENSSL_free(sess->id);
+ OPENSSL_free(sess->der);
+ OPENSSL_free(sess);
+ return;
+ }
+ prev = sess;
+ }
+ }
+
+static void init_session_cache_ctx(SSL_CTX *sctx)
+ {
+ SSL_CTX_set_session_cache_mode(sctx,
+ SSL_SESS_CACHE_NO_INTERNAL|SSL_SESS_CACHE_SERVER);
+ SSL_CTX_sess_set_new_cb(sctx, add_session);
+ SSL_CTX_sess_set_get_cb(sctx, get_session);
+ SSL_CTX_sess_set_remove_cb(sctx, del_session);
+ }
+
+static void free_sessions(void)
+ {
+ simple_ssl_session *sess, *tsess;
+ for (sess = first; sess;)
+ {
+ OPENSSL_free(sess->id);
+ OPENSSL_free(sess->der);
+ tsess = sess;
+ sess = sess->next;
+ OPENSSL_free(tsess);
+ }
+ first = NULL;
+ }
+
+
+
+
+
+
+
+
+
+