1 files changed, 51 insertions, 8 deletions

diff --git a/lib9p/srv.c b/lib9p/srv.c
index 039b4c2..74c2014 100644
--- a/lib9p/srv.c
+++ b/lib9p/srv.c
@@ -10,18 +10,24 @@
 #include <lib9p/srv.h>
 #include "internal.h"
 
-struct lib9p_srvconn {
+/* The hierarchy of concepts is:
+ *
+ *     server -> connection -> session -> request
+ *
+ */
+
+struct lib9p_srv_sess {
 	/* immutable */
 	struct lib9p_srv        *srv;
-	cid_t                    reader;
-	int                      fd;
+	int                      connfd;
+	cid_t                    reader; /* the lib9p_srv_read_cr() coroutine for this session */
 	/* mutable */
 	struct lib9p_ctx         ctx;
 	unsigned int             refcount;
 };
 
-struct lib9p_srvreq {
-	struct lib9p_srvconn    *conn;
+struct lib9p_srv_req {
+	struct lib9p_srv_sess   *sess;
 	uint8_t                 *msg;
 };
 
@@ -79,7 +85,7 @@ COROUTINE lib9p_srv_read_cr(void *_srv) {
 			}
 			goal = decode_u32le(buf);
 			if (goal < 7) {
-				/* We can't respond with an Rerror becuase we wouldn't know what tag to use!  */ 
+				/* We can't even respond with an Rerror becuase we wouldn't know what tag to use!  */ 
 				fprintf(stderr, "error: T-message is impossibly small");
 				goto close;
 			}
@@ -184,5 +190,42 @@ void handle_message(struct lib9p_srvconn *conn, uint8_t *net) {
 	netio_write(req.conn->fd, net, decode_u32le(net));
 }
 
-// EMSGSIZE for request too large
-// EPROTONOSUPPORT for version errors
+void _version(struct lib9p_srv_req *ctx, struct lib9p_msg_Tversion *req, struct lib9p_msg_Rversion *resp) {
+	enum lib9p_version version = LIB9P_VER_unknown;
+
+	if (req->version.len >= 6 &&
+	    req->version.utf8[0] == '9' && 
+	    req->version.utf8[1] == 'P' && 
+	    '0' <= req->version.utf8[2] && req->version.utf8[2] <= '9' &&
+	    '0' <= req->version.utf8[3] && req->version.utf8[3] <= '9' &&
+	    '0' <= req->version.utf8[4] && req->version.utf8[4] <= '9' &&
+	    '0' <= req->version.utf8[5] && req->version.utf8[5] <= '9' &&
+	    (req->version.utf8[6] == '\0' || req->version.utf8[6] == '.')) {
+		if (strcmp(&req->version.utf8[6], ".u") == 0)
+			version = LIB9P_VER_9P2000_u;
+		//else if (strcmp(&req->version.utf8[6], ".e") == 0)
+		//	version = LIB9P_VER_9P2000_e;
+		else
+			version = LIB9P_VER_9P2000;
+	}
+
+	struct lib9p_ctx empty_ctx = {
+		.version      = version,
+		.max_msg_size = CONFIG_9P_MAX_MSG_SIZE,
+	};
+	struct lib9p_msg_Rerror empty_error = { 0 };
+	assert(!lib9p_marshal(&empty_ctx, LIB9P_TYP_Rerror, 0, &empty_error, ctx->net));
+	uint32_t min_msg_size = decode_u32le(ctx->net);
+	assert(CONFIG_9P_MAX_MSG_SIZE >= min_msg_size);
+
+	if (req->max_msg_size < min_msg_size) {
+		lib9p_errorf(&ctx->ctx, LINUX_EDOM, "requested max_msg_size is less than minimum for %s (%"PRIu32" < %"PRIu32")",
+		             version, req->max_msg_size, min_msg_size);
+		return;
+	}
+
+	resp->version = lib9p_version_str(version);
+	resp->max_msg_size = (CONFIG_9P_MAX_MSG_SIZE < req->max_msg_size)
+		? CONFIG_9P_MAX_MSG_SIZE
+		: req->max_msg_size;
+}