diff --git a/Makefile b/Makefile
index 2b1487d..c9ca5f6 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,9 @@
 LIB=		9p
 SHLIB_MAJOR=	1
-SRCS=		lib9p.c connection.c request.c log.c transport/socket.c backend/fs.c
+SRCS=		pack.c connection.c request.c log.c utils.c transport/socket.c backend/fs.c
 INCS=		lib9p.h fcall.h log.h backend/fs.h
 CFLAGS=		-g -O0
 
+LIBADD=		sbuf
+
 .include <bsd.lib.mk>
diff --git a/backend/fs.c b/backend/fs.c
index 84b6b22..34df344 100644
--- a/backend/fs.c
+++ b/backend/fs.c
@@ -31,6 +31,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <stdbool.h>
 #include <fcntl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -53,6 +54,7 @@ static void fs_wstat(void *, struct l9p_request *);
 struct fs_softc
 {
 	const char *fs_rootpath;
+	bool fs_readonly;
 };
 
 struct openfile
@@ -67,7 +69,7 @@ open_fid(const char *path)
 {
 	struct openfile *ret;
 
-	ret = malloc(sizeof(*ret));
+	ret = calloc(1, sizeof(*ret));
 	ret->fd = -1;
 	ret->name = strdup(path);
 	return (ret);
@@ -79,7 +81,7 @@ dostat(struct l9p_stat *s, char *name, struct stat *buf)
 	char *user = getenv("USER");
 	s->type = 0;
 	s->dev = 0;
-	s->qid.type = buf->st_mode&S_IFMT;
+	s->qid.type = buf->st_mode&S_IFMT >> 8;
 	s->qid.path = buf->st_ino;
 	s->qid.version = 0;
 	s->mode = buf->st_mode & 0777;
@@ -112,6 +114,19 @@ fs_attach(void *softc, struct l9p_request *req)
 static void
 fs_clunk(void *softc, struct l9p_request *req)
 {
+	struct l9p_connection *conn = req->lr_conn;
+	struct openfile *file;
+	struct stat st;
+
+	file = req->lr_fid->lo_aux;
+
+	if (file->dir)
+		closedir(file->dir);
+	else {
+		close(file->fd);
+		file->fd = -1;
+	}
+
 	l9p_respond(req, NULL);
 }
 
@@ -124,12 +139,13 @@ fs_create(void *softc, struct l9p_request *req)
 static void
 fs_flush(void *softc, struct l9p_request *req)
 {
-
+	l9p_respond(req, NULL);
 }
 
 static void
 fs_open(void *softc, struct l9p_request *req)
 {
+	struct l9p_connection *conn = req->lr_conn;
 	struct openfile *file;
 	struct stat st;
 
@@ -142,12 +158,12 @@ fs_open(void *softc, struct l9p_request *req)
 	} else {
 		file->fd = open(file->name, O_RDONLY);
 		if (file->fd < 0) {
-			l9p_respond(req, "ENOPERM");
+			l9p_respond(req, "Permission denied");
 			return;
 		}
 	}
 
-	req->lr_resp.ropen.iounit = 512;
+	req->lr_resp.ropen.iounit = conn->lc_max_io_size;
 	l9p_respond(req, NULL);
 }
 
@@ -155,6 +171,7 @@ static void
 fs_read(void *softc, struct l9p_request *req)
 {
 	struct openfile *file;
+	struct l9p_connection *conn = req->lr_conn;
 	struct l9p_stat l9stat;
 
 	file = req->lr_fid->lo_aux;
@@ -163,15 +180,24 @@ fs_read(void *softc, struct l9p_request *req)
 		struct dirent *d;
 		struct stat st;
 
-		d = readdir(file->dir);
-		if (d) {
-			stat(d->d_name, &st);
-			dostat(&l9stat, d->d_name, &st);
-			l9p_pack_stat(req, &l9stat);
+		for (;;) {
+			d = readdir(file->dir);
+			if (d) {
+				stat(d->d_name, &st);
+				dostat(&l9stat, d->d_name, &st);
+				if (l9p_pack_stat(req, &l9stat) != 0) {
+					seekdir(file->dir, -1);
+					break;
+				}
+
+				continue;
+			}
+
+			break;
 		}
 	} else {
-		req->lr_resp.io.data = malloc(req->lr_req.io.count);
-		req->lr_resp.io.count = read(file->fd, req->lr_resp.io.data, req->lr_req.io.count);
+		size_t niov = l9p_truncate_iov(req->lr_data_iov, req->lr_data_niov, req->lr_req.io.count);
+		req->lr_resp.io.count = readv(file->fd, req->lr_data_iov, niov);
 	}
 
 	l9p_respond(req, NULL);
@@ -186,7 +212,16 @@ fs_remove(void *softc, struct l9p_request *req)
 static void
 fs_stat(void *softc, struct l9p_request *req)
 {
+	struct openfile *file;
+	struct stat st;
+	struct l9p_stat l9stat;
 
+	file = req->lr_fid->lo_aux;
+
+	stat(file->name, &st);
+	dostat(&req->lr_resp.rstat.stat, file->name, &st);
+
+	l9p_respond(req, NULL);
 }
 
 static void
@@ -200,11 +235,11 @@ fs_walk(void *softc, struct l9p_request *req)
 	strcpy(name, file->name);
 
 	/* build full path. Stat full path. Done */
-	for(i=0; i < req->lr_req.twalk.nwname; i++) {
+	for (i = 0; i < req->lr_req.twalk.nwname; i++) {
 		strcat(name, "/");
 		strcat(name, req->lr_req.twalk.wname[i]);
 		if (stat(name, &buf) < 0){
-			l9p_respond(req, "no such file");
+			l9p_respond(req, "No such file or directory");
 			free(name);
 			return;
 		}
diff --git a/connection.c b/connection.c
index 8d213cb..bac8343 100644
--- a/connection.c
+++ b/connection.c
@@ -26,6 +26,8 @@
  */
 
 #include <stdlib.h>
+#include <string.h>
+#include <errno.h>
 #include <sys/queue.h>
 #include "lib9p.h"
 #include "log.h"
@@ -35,7 +37,7 @@ l9p_server_init(struct l9p_server **serverp, struct l9p_backend *backend)
 {
     struct l9p_server *server;
 
-    server = malloc(sizeof(*server));
+    server = calloc(1, sizeof(*server));
     server->ls_backend = backend;
     LIST_INIT(&server->ls_conns);
 
@@ -48,8 +50,11 @@ l9p_connection_init(struct l9p_server *server, struct l9p_connection **conn)
 {
     struct l9p_connection *newconn;
 
-    newconn = malloc(sizeof(*newconn));
+    newconn = calloc(1, sizeof(*newconn));
     newconn->lc_server = server;
+    newconn->lc_msize = L9P_DEFAULT_MSIZE;
+    LIST_INIT(&newconn->lc_requests);
+    LIST_INIT(&newconn->lc_files);
     LIST_INSERT_HEAD(&server->ls_conns, newconn, lc_link);
     *conn = newconn;
 
@@ -63,29 +68,48 @@ l9p_connection_free(struct l9p_connection *conn)
 }
 
 void
-l9p_connection_on_send_request(struct l9p_connection *conn,
-    void (*cb)(void *, size_t, void *), void *softc)
+l9p_connection_on_send_response(struct l9p_connection *conn,
+    l9p_send_response_t cb, void *aux)
 {
 
-    conn->lc_send_request = cb;
-    conn->lc_send_request_aux = softc;
+    conn->lc_send_response = cb;
+    conn->lc_send_response_aux = aux;
 }
 
 void
-l9p_connection_recv(struct l9p_connection *conn, void *buf, size_t len)
+l9p_connection_on_get_response_buffer(struct l9p_connection *conn,
+    l9p_get_response_buffer_t cb, void *aux)
+{
+
+    conn->lc_get_response_buffer = cb;
+    conn->lc_get_response_buffer_aux = aux;
+}
+
+void
+l9p_connection_recv(struct l9p_connection *conn, const struct iovec *iov,
+    const size_t niov, void *aux)
 {
-    struct l9p_message msg;
     struct l9p_request *req;
 
-    req = malloc(sizeof(struct l9p_request));
+    req = calloc(1, sizeof(struct l9p_request));
+    req->lr_aux = aux;
     req->lr_conn = conn;
-    msg.lm_buffer = buf;
-    msg.lm_pos = buf;
-    msg.lm_end = buf + len;
-    msg.lm_mode = L9P_UNPACK;
 
-    if (l9p_pufcall(&msg, &req->lr_req) != 0) {
-        l9p_logf(L9P_WARNING, "cannot unpack received message");
+    req->lr_req_msg.lm_mode = L9P_UNPACK;
+    req->lr_req_msg.lm_niov = niov;
+    memcpy(req->lr_req_msg.lm_iov, iov, sizeof(struct iovec) * niov);
+    
+    req->lr_resp_msg.lm_mode = L9P_PACK;
+
+    if (l9p_pufcall(&req->lr_req_msg, &req->lr_req) != 0){
+        L9P_LOG(L9P_WARNING, "cannot unpack received message");
+        return;
+    }
+
+    if (conn->lc_get_response_buffer(req, req->lr_resp_msg.lm_iov,
+        &req->lr_resp_msg.lm_niov, conn->lc_get_response_buffer_aux) != 0) {
+        L9P_LOG(L9P_WARNING, "cannot obtain buffers for response");
+        return;
     }
 
     l9p_dispatch_request(req);
@@ -97,6 +121,24 @@ l9p_connection_close(struct l9p_connection *conn)
 
 }
 
+struct l9p_openfile *
+l9p_connection_alloc_fid(struct l9p_connection *conn, uint32_t fid)
+{
+    struct l9p_openfile *file;
+
+    if (l9p_connection_find_fid(conn, fid) != NULL) {
+        errno = EEXIST;
+        return (NULL);
+    }
+
+    file = calloc(1, sizeof(struct l9p_openfile));
+    file->lo_fid = fid;
+    file->lo_conn = conn;
+    LIST_INSERT_HEAD(&conn->lc_files, file, lo_link);
+
+    return (file);
+}
+
 struct l9p_openfile *
 l9p_connection_find_fid(struct l9p_connection *conn, uint32_t fid)
 {
@@ -110,6 +152,13 @@ l9p_connection_find_fid(struct l9p_connection *conn, uint32_t fid)
     return (NULL);
 }
 
+void
+l9p_connection_remove_fid(struct l9p_connection *conn, struct l9p_openfile *fid)
+{
+
+    LIST_REMOVE(fid, lo_link);
+}
+
 struct l9p_request *
 l9p_connection_find_tag(struct l9p_connection *conn, uint32_t tag)
 {
diff --git a/fcall.h b/fcall.h
index 9117f21..efa49ff 100644
--- a/fcall.h
+++ b/fcall.h
@@ -193,8 +193,7 @@ struct l9p_f_io
 struct l9p_f_rstat
 {
     struct l9p_hdr hdr;
-    uint16_t nstat;
-    uint8_t *stat;
+    struct l9p_stat stat;
 };
 
 struct l9p_f_twstat
@@ -224,4 +223,4 @@ union l9p_fcall
     struct l9p_f_io io;
 };
 
-#endif //LIB9P_FCALL_H
+#endif  /* LIB9P_FCALL_H */
diff --git a/lib9p.h b/lib9p.h
index cc67a9e..e180b0b 100644
--- a/lib9p.h
+++ b/lib9p.h
@@ -29,14 +29,28 @@
 #ifndef LIB9P_LIB9P_H
 #define LIB9P_LIB9P_H
 
+#include <stdio.h>
 #include <sys/types.h>
 #include <sys/queue.h>
+#include <sys/uio.h>
+#include <sys/sbuf.h>
 #include <pthread.h>
 #include "fcall.h"
 
-#define L9P_ENOFID "FID does not exist"
-#define L9P_ENOFUNC "Function not implemented"
-#define L9P_EINTR "Interrupted"
+#define L9P_DEFAULT_MSIZE   8192
+#define L9P_MAX_IOV         8
+
+#define L9P_ENOFID      "FID does not exist"
+#define L9P_ENOFUNC     "Function not implemented"
+#define L9P_EINTR       "Interrupted"
+
+struct l9p_request;
+
+typedef int (l9p_get_response_buffer_t)(struct l9p_request *,
+    struct iovec *, size_t *, void *);
+
+typedef int (l9p_send_response_t)(struct l9p_request *, const struct iovec *,
+    const size_t, const size_t, void *);
 
 enum l9p_pack_mode
 {
@@ -52,23 +66,38 @@ enum l9p_integer_type
     L9P_QWORD = 8
 };
 
+enum l9p_version
+{
+    L9P_2000 = 1,
+    L9P_2000U = 2,
+    L9P_2000L = 3
+};
+
 struct l9p_message
 {
     enum l9p_pack_mode lm_mode;
-    uint8_t *lm_buffer;
-    uint8_t *lm_pos;
-    uint8_t *lm_end;
+    struct iovec lm_iov[L9P_MAX_IOV];
+    size_t lm_niov;
+    size_t lm_cursor_iov;
+    size_t lm_cursor_offset;
+    size_t lm_size;
 };
 
 struct l9p_request
 {
     uint32_t lr_tag;
+    struct l9p_message lr_req_msg;
+    struct l9p_message lr_resp_msg;
+    struct l9p_message lr_readdir_msg;
     union l9p_fcall lr_req;
     union l9p_fcall lr_resp;
     struct l9p_openfile *lr_fid;
     struct l9p_openfile *lr_newfid;
     struct l9p_connection *lr_conn;
     pthread_t lr_thread;
+    void *lr_aux;
+    struct iovec lr_data_iov[L9P_MAX_IOV];
+    size_t lr_data_niov;
     LIST_ENTRY(l9p_request) lr_link;
 };
 
@@ -85,9 +114,14 @@ struct l9p_openfile
 struct l9p_connection
 {
     struct l9p_server *lc_server;
+    enum l9p_version lc_version;
     pthread_mutex_t lc_send_lock;
-    void (*lc_send_request)(const void *, const size_t, void *);
-    void *lc_send_request_aux;
+    uint32_t lc_msize;
+    uint32_t lc_max_io_size;
+    l9p_send_response_t *lc_send_response;
+    l9p_get_response_buffer_t *lc_get_response_buffer;
+    void *lc_get_response_buffer_aux;
+    void *lc_send_response_aux;
     void *lc_softc;
     LIST_HEAD(, l9p_request) lc_requests;
     LIST_HEAD(, l9p_openfile) lc_files;
@@ -97,6 +131,7 @@ struct l9p_connection
 struct l9p_server
 {
     struct l9p_backend *ls_backend;
+    enum l9p_version ls_max_version;
     LIST_HEAD(, l9p_connection) ls_conns;
 };
 
@@ -118,19 +153,36 @@ struct l9p_backend
 };
 
 int l9p_pufcall(struct l9p_message *msg, union l9p_fcall *fcall);
-int l9p_fustat(struct l9p_message *msg, struct l9p_stat *s);
+int l9p_pustat(struct l9p_message *msg, struct l9p_stat *s);
 uint16_t l9p_sizeof_stat(struct l9p_stat *stat);
 int l9p_pack_stat(struct l9p_request *req, struct l9p_stat *s);
 
-int l9p_server_init(struct l9p_server **, struct l9p_backend *backend);
+int l9p_server_init(struct l9p_server **serverp, struct l9p_backend *backend);
 
-int l9p_connection_init(struct l9p_server *server, struct l9p_connection **conn);
+int l9p_connection_init(struct l9p_server *server,
+    struct l9p_connection **connp);
 void l9p_connection_free(struct l9p_connection *conn);
-void l9p_connection_on_send_request(struct l9p_connection *conn, void (*cb)(void *, size_t, void *), void *);
-void l9p_connection_recv(struct l9p_connection *conn, void *buf, size_t len);
+void l9p_connection_on_send_response(struct l9p_connection *conn,
+    l9p_send_response_t *cb, void *aux);
+void l9p_connection_on_get_response_buffer(struct l9p_connection *conn,
+    l9p_get_response_buffer_t *cb, void *aux);
+void l9p_connection_recv(struct l9p_connection *conn, const struct iovec *iov,
+    size_t niov, void *aux);
 void l9p_connection_close(struct l9p_connection *conn);
-struct l9p_openfile *l9p_connection_find_fid(struct l9p_connection *conn, uint32_t fid);
-struct l9p_request *l9p_connection_find_tag(struct l9p_connection *conn, uint32_t tag);
+struct l9p_openfile *l9p_connection_alloc_fid(struct l9p_connection *conn,
+    uint32_t fid);
+struct l9p_openfile *l9p_connection_find_fid(struct l9p_connection *conn,
+    uint32_t fid);
+void l9p_connection_remove_fid(struct l9p_connection *conn,
+    struct l9p_openfile *fid);
+struct l9p_request *l9p_connection_find_tag(struct l9p_connection *conn,
+    uint32_t tag);
 void l9p_respond(struct l9p_request *req, const char *error);
 
-#endif //LIB9P_LIB9P_H
+void l9p_seek_iov(struct iovec *iov1, size_t niov1, struct iovec *iov2,
+    size_t *niov2, size_t seek);
+int l9p_truncate_iov(struct iovec *iov, size_t niov, size_t length);
+void l9p_describe_qid(struct l9p_qid *qid, struct sbuf *sb);
+void l9p_describe_fcall(union l9p_fcall *fcall, enum l9p_version version, struct sbuf *sb);
+
+#endif  /* LIB9P_LIB9P_H */
diff --git a/log.c b/log.c
index 98cc62d..ff65b3f 100644
--- a/log.c
+++ b/log.c
@@ -37,12 +37,12 @@ static const char *l9p_log_level_names[] = {
 };
 
 void
-l9p_logf(enum l9p_log_level level, const char *fmt, ...)
+l9p_logf(enum l9p_log_level level, const char *func, const char *fmt, ...)
 {
 	va_list ap;
 
 	va_start(ap, fmt);
-	fprintf(stderr, "[%s]\t", l9p_log_level_names[level]);
+	fprintf(stderr, "[%s]\t %s: ", l9p_log_level_names[level], func);
 	vfprintf(stderr, fmt, ap);
 	fprintf(stderr, "\n");
 	va_end(ap);
diff --git a/log.h b/log.h
index 9b3d1fa..cd3eabc 100644
--- a/log.h
+++ b/log.h
@@ -36,6 +36,8 @@ enum l9p_log_level
 	L9P_ERROR
 };
 
-void l9p_logf(enum l9p_log_level level, const char *fmt, ...);
+void l9p_logf(enum l9p_log_level level, const char *func, const char *fmt, ...);
 
+#define	L9P_LOG(level, fmt, ...) l9p_logf(level, __func__, fmt, ##__VA_ARGS__)
+	
 #endif	/* LIB9P_LOG_H */
diff --git a/lib9p.c b/pack.c
similarity index 55%
rename from lib9p.c
rename to pack.c
index c329bbc..8c06a70 100644
--- a/lib9p.c
+++ b/pack.c
@@ -31,124 +31,119 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <assert.h>
 #include <sys/types.h>
+#include <sys/param.h>
+#include <sys/uio.h>
 #include "lib9p.h"
 
 #define N(ary)          (sizeof(ary) / sizeof(*ary))
 #define STRING_SIZE(s)  (L9P_WORD + strlen(s))
 #define QID_SIZE        (L9P_BYTE + L9P_DWORD + L9P_QWORD)
 
-static void l9p_puint(struct l9p_message *, enum l9p_integer_type, uint32_t *);
-static inline void l9p_pu8(struct l9p_message *, uint8_t *);
-static inline void l9p_pu16(struct l9p_message *, uint16_t *);
-static inline void l9p_pu32(struct l9p_message *, uint32_t *);
-static inline void l9p_pu64(struct l9p_message *, uint64_t *);
-static void l9p_pustring(struct l9p_message *, char **s);
-static void l9p_pustrings(struct l9p_message *, uint16_t *,char *[], size_t);
-static void l9p_pudata(struct l9p_message *, uint8_t **, size_t);
-static void l9p_puqid(struct l9p_message *, struct l9p_qid *);
-static void l9p_puqids(struct l9p_message *, uint16_t *, struct l9p_qid *q,
+static int l9p_iov_io(struct l9p_message *, void *, size_t);
+static int l9p_puint(struct l9p_message *, enum l9p_integer_type, uint32_t *);
+static inline int l9p_pu8(struct l9p_message *, uint8_t *);
+static inline int l9p_pu16(struct l9p_message *, uint16_t *);
+static inline int l9p_pu32(struct l9p_message *, uint32_t *);
+static inline int l9p_pu64(struct l9p_message *, uint64_t *);
+static int l9p_pustring(struct l9p_message *, char **s);
+static int l9p_pustrings(struct l9p_message *, uint16_t *,char *[], size_t);
+static int l9p_pudata(struct l9p_message *, uint8_t **, size_t);
+static int l9p_puqid(struct l9p_message *, struct l9p_qid *);
+static int l9p_puqids(struct l9p_message *, uint16_t *, struct l9p_qid *q,
     size_t);
 
-
-static void
-l9p_puint(struct l9p_message *msg, enum l9p_integer_type size, uint32_t *val)
+static int
+l9p_iov_io(struct l9p_message *msg, void *buffer, size_t len)
 {
-    uint8_t *pos;
-    int v;
+    size_t done = 0;
+    size_t left = len;
 
-    if(msg->lm_pos + size <= msg->lm_end) {
-        pos = (uint8_t*)msg->lm_pos;
-        switch (msg->lm_mode) {
-            case L9P_PACK:
-                v = *val;
-                switch (size) {
-                    case L9P_DWORD:
-                        pos[3] = v>>24;
-                        pos[2] = v>>16;
-                    case L9P_WORD:
-                        pos[1] = v>>8;
-                    case L9P_BYTE:
-                        pos[0] = v;
-                        break;
-                }
-            case L9P_UNPACK:
-                v = 0;
-                switch (size) {
-                    case L9P_DWORD:
-                        v |= pos[3]<<24;
-                        v |= pos[2]<<16;
-                    case L9P_WORD:
-                        v |= pos[1]<<8;
-                    case L9P_BYTE:
-                        v |= pos[0];
-                        break;
-                }
-                *val = v;
+    assert(msg != NULL);
+    assert(buffer != NULL);
+
+    if (len == 0)
+        return (0);
+
+    if (msg->lm_cursor_iov >= msg->lm_niov)
+        return (-1);
+
+    while (left > 0) {
+        size_t idx = msg->lm_cursor_iov;
+        size_t space = msg->lm_iov[idx].iov_len - msg->lm_cursor_offset;
+        size_t towrite = MIN(space, left);
+
+        if (msg->lm_mode == L9P_PACK)
+            memcpy(msg->lm_iov[idx].iov_base + msg->lm_cursor_offset,
+                buffer + done, towrite);
+
+        if (msg->lm_mode == L9P_UNPACK)
+            memcpy(buffer + done, msg->lm_iov[idx].iov_base +
+                msg->lm_cursor_offset, towrite);
+
+        msg->lm_cursor_offset += towrite;
+
+        if (space - towrite == 0) {
+            /* Advance to next iov */
+            msg->lm_cursor_iov++;
+            msg->lm_cursor_offset = 0;
+
+            if (msg->lm_cursor_iov > msg->lm_niov)
+                return (-1);
         }
+
+        done += towrite;
+        left -= towrite;
     }
-    msg->lm_pos += size;
+
+    msg->lm_size += done;
+    return (done);
 }
 
-static inline void
+static inline int
 l9p_pu8(struct l9p_message *msg, uint8_t *val)
 {
-    uint32_t v;
-
-    v = *val;
-    l9p_puint(msg, L9P_BYTE, &v);
-    *val = (uint8_t)v;
+    return (l9p_iov_io(msg, val, sizeof(uint8_t)));
 }
 
-static inline void
+static inline int
 l9p_pu16(struct l9p_message *msg, uint16_t *val)
 {
-    uint32_t v;
-
-    v = *val;
-    l9p_puint(msg, L9P_WORD, &v);
-    *val = (uint16_t)v;
+    return (l9p_iov_io(msg, val, sizeof(uint16_t)));
 }
 
-static inline void
+static inline int
 l9p_pu32(struct l9p_message *msg, uint32_t *val)
 {
-    l9p_puint(msg, L9P_DWORD, val);
+    return(l9p_iov_io(msg, val, sizeof(uint32_t)));
 }
 
-static inline void
+static inline int
 l9p_pu64(struct l9p_message *msg, uint64_t *val)
 {
-    uint32_t vl, vb;
-
-    vl = (uint)*val;
-    vb = (uint)(*val>>32);
-    l9p_puint(msg, L9P_DWORD, &vl);
-    l9p_puint(msg, L9P_DWORD, &vb);
-    *val = vl | ((uint64_t)vb<<32);
+    return(l9p_iov_io(msg, val, sizeof(uint64_t)));
 }
 
-static void
+static int
 l9p_pustring(struct l9p_message *msg, char **s)
 {
     uint16_t len;
 
-    if(msg->lm_mode == L9P_PACK)
+    if (msg->lm_mode == L9P_PACK)
         len = strlen(*s);
-    l9p_pu16(msg, &len);
 
-    if (msg->lm_pos + len <= msg->lm_end) {
-        if (msg->lm_mode == L9P_UNPACK) {
-            *s = malloc(len + 1);
-            memcpy(*s, msg->lm_pos, len);
-            (*s)[len] = '\0';
-        } else
-            memcpy(msg->lm_pos, *s, len);
-    }
-    msg->lm_pos += len;
+    if (l9p_pu16(msg, &len) < 0)
+        return (-1);
+
+    if (msg->lm_mode == L9P_UNPACK)
+        *s = calloc(1, len + 1);
+
+    if (l9p_iov_io(msg, *s, len) < 0)
+        return (-1);
 }
 
-static void
+static int
 l9p_pustrings(struct l9p_message *msg, uint16_t *num, char *strings[],
     size_t max)
 {
@@ -157,105 +152,78 @@ l9p_pustrings(struct l9p_message *msg, uint16_t *num, char *strings[],
     uint16_t len;
 
     l9p_pu16(msg, num);
-    if (*num > max) {
-        msg->lm_pos = msg->lm_end+1;
-        return;
-    }
 
-    s = NULL;
-
-    if (msg->lm_mode == L9P_UNPACK) {
-        s = msg->lm_pos;
-        size = 0;
-        for (i = 0; i < *num; i++) {
-            l9p_pu16(msg, &len);
-            msg->lm_pos += len;
-            size += len;
-            if (msg->lm_pos > msg->lm_end)
-                return;
-        }
-        msg->lm_pos = s;
-        size += *num;
-        s = malloc(size);
-    }
-
-    for (i = 0; i < *num; i++) {
-        if (msg->lm_mode == L9P_PACK)
-            len = strlen(strings[i]);
-        l9p_pu16(msg, &len);
-
-        if (msg->lm_mode == L9P_UNPACK) {
-            memcpy(s, msg->lm_pos, len);
-            strings[i] = (char*)s;
-            s += len;
-            msg->lm_pos += len;
-            *s++ = '\0';
-        } else
-            l9p_pudata(msg, &strings[i], len);
+    for (i = 0; i < MIN(*num, max); i++) {
+        if (l9p_pustring(msg, &strings[i]) < 0)
+            return (-1);
     }
 }
 
-static void
+static int
 l9p_pudata(struct l9p_message *msg, uint8_t **data, size_t len)
 {
-    if (msg->lm_pos + len <= msg->lm_end) {
-        if (msg->lm_mode == L9P_UNPACK) {
-            *data = malloc(len);
-            memcpy(*data, msg->lm_pos, len);
-        } else
-            memcpy(msg->lm_pos, *data, len);
-    }
-    msg->lm_pos += len;
+    if (msg->lm_mode == L9P_UNPACK)
+        *data = malloc(len);
+        
+    return (l9p_iov_io(msg, *data, len));
 }
 
-static void
+static int
 l9p_puqid(struct l9p_message *msg, struct l9p_qid *qid)
 {
-    l9p_pu8(msg, &qid->type);
-    l9p_pu32(msg, &qid->version);
-    l9p_pu64(msg, &qid->path);
+    int r = 0;
+
+    r += l9p_pu8(msg, (uint8_t *)&qid->type);
+    r += l9p_pu32(msg, &qid->version);
+    r += l9p_pu64(msg, &qid->path);
+
+    return (r);
 }
 
-static void
+static int
 l9p_puqids(struct l9p_message *msg, uint16_t *num, struct l9p_qid *qids,
     size_t max)
 {
     int i;
     l9p_pu16(msg, num);
-    if (*num > max) {
-        msg->lm_pos = msg->lm_end + 1;
-        return;
-    }
 
-    for (i = 0; i < *num; i++)
-        l9p_puqid(msg, &qids[i]);
+    for (i = 0; i < *num; i++) {
+        if (l9p_puqid(msg, &qids[i]) < 0)
+            return (-1);
+    }
 }
 
-void
+int
 l9p_pustat(struct l9p_message *msg, struct l9p_stat *stat)
 {
+    int r = 0;
     uint16_t size;
 
-    if(msg->lm_mode == L9P_PACK)
+    if (msg->lm_mode == L9P_PACK)
         size = l9p_sizeof_stat(stat) - 2;
 
-    l9p_pu16(msg, &size);
-    l9p_pu16(msg, &stat->type);
-    l9p_pu32(msg, &stat->dev);
-    l9p_puqid(msg, &stat->qid);
-    l9p_pu32(msg, &stat->mode);
-    l9p_pu32(msg, &stat->atime);
-    l9p_pu32(msg, &stat->mtime);
-    l9p_pu64(msg, &stat->length);
-    l9p_pustring(msg, &stat->name);
-    l9p_pustring(msg, &stat->uid);
-    l9p_pustring(msg, &stat->gid);
-    l9p_pustring(msg, &stat->muid);
+    r += l9p_pu16(msg, &size);
+    r += l9p_pu16(msg, &stat->type);
+    r += l9p_pu32(msg, &stat->dev);
+    r += l9p_puqid(msg, &stat->qid);
+    r += l9p_pu32(msg, &stat->mode);
+    r += l9p_pu32(msg, &stat->atime);
+    r += l9p_pu32(msg, &stat->mtime);
+    r += l9p_pu64(msg, &stat->length);
+    r += l9p_pustring(msg, &stat->name);
+    r += l9p_pustring(msg, &stat->uid);
+    r += l9p_pustring(msg, &stat->gid);
+    r += l9p_pustring(msg, &stat->muid);
+
+    return (r);
 }
 
 int
 l9p_pufcall(struct l9p_message *msg, union l9p_fcall *fcall)
 {
+    uint32_t length = 0;
+
+    l9p_pu32(msg, &length);
     l9p_pu8(msg, &fcall->hdr.type);
     l9p_pu16(msg, &fcall->hdr.tag);
 
@@ -320,13 +288,11 @@ l9p_pufcall(struct l9p_message *msg, union l9p_fcall *fcall)
             break;
         case L9P_RREAD:
             l9p_pu32(msg, &fcall->io.count);
-            l9p_pudata(msg, &fcall->io.data, fcall->io.count);
             break;
         case L9P_TWRITE:
             l9p_pu32(msg, &fcall->hdr.fid);
             l9p_pu64(msg, &fcall->io.offset);
             l9p_pu32(msg, &fcall->io.count);
-            l9p_pudata(msg, &fcall->io.data, fcall->io.count);
             break;
         case L9P_RWRITE:
             l9p_pu32(msg, &fcall->io.count);
@@ -336,16 +302,33 @@ l9p_pufcall(struct l9p_message *msg, union l9p_fcall *fcall)
             l9p_pu32(msg, &fcall->hdr.fid);
             break;
         case L9P_RSTAT:
-            l9p_pu16(msg, &fcall->rstat.nstat);
-            l9p_pudata(msg, (char**)&fcall->rstat.stat, fcall->rstat.nstat);
+            {
+                uint16_t size = l9p_sizeof_stat(&fcall->rstat.stat);
+                l9p_pu16(msg, &size);
+                l9p_pustat(msg, &fcall->rstat.stat);
+            }
             break;
-        case L9P_TWSTAT: {
-            uint16_t size;
-            l9p_pu32(msg, &fcall->hdr.fid);
-            l9p_pu16(msg, &size);
-            l9p_pustat(msg, &fcall->twstat.stat);
+        case L9P_TWSTAT:
+            {
+                uint16_t size;
+                l9p_pu32(msg, &fcall->hdr.fid);
+                l9p_pu16(msg, &size);
+                l9p_pustat(msg, &fcall->twstat.stat);
+            }
             break;
-        }
+    }
+
+    if (msg->lm_mode == L9P_PACK) {
+        /* Rewind to the beginning */
+        uint32_t len = msg->lm_size;
+        msg->lm_cursor_offset = 0;
+        msg->lm_cursor_iov = 0;
+        msg->lm_size -= sizeof(uint32_t);
+
+        if (fcall->hdr.type == L9P_RREAD)
+            len += fcall->io.count;
+
+        l9p_pu32(msg, &len);
     }
 
     return (0);
@@ -358,7 +341,7 @@ l9p_sizeof_stat(struct l9p_stat *stat) {
         + L9P_DWORD /* dev */
         + QID_SIZE /* qid */
         + 3 * L9P_DWORD /* mode, atime, mtime */
-        + L9P_DWORD /* length */
+        + L9P_QWORD /* length */
         + STRING_SIZE(stat->name)
         + STRING_SIZE(stat->uid)
         + STRING_SIZE(stat->gid)
diff --git a/request.c b/request.c
index ab8c945..40bb038 100644
--- a/request.c
+++ b/request.c
@@ -25,8 +25,11 @@
  *
  */
 
-
+#include <stdlib.h>
 #include <string.h>
+#include <sys/param.h>
+#include <sys/uio.h>
+#include <sys/sbuf.h>
 #include "lib9p.h"
 #include "fcall.h"
 #include "log.h"
@@ -46,7 +49,7 @@ static void l9p_dispatch_twalk(struct l9p_request *req);
 static void l9p_dispatch_twrite(struct l9p_request *req);
 static void l9p_dispatch_twstat(struct l9p_request *req);
 
-static struct
+static const struct
 {
     enum l9p_ftype type;
     void (*handler)(struct l9p_request *);
@@ -65,13 +68,25 @@ static struct
     {L9P_TWSTAT, l9p_dispatch_twstat}
 };
 
+static const char *l9p_versions[] = {
+    "9P2000",
+    "9P2000.u",
+    "9P2000.L"
+};
+
 void
 l9p_dispatch_request(struct l9p_request *req)
 {
     struct l9p_connection *conn = req->lr_conn;
+    struct sbuf *sb = sbuf_new_auto();
     int i;
 
-    l9p_logf(L9P_INFO, "new request of type %d", req->lr_req.hdr.type);
+    l9p_describe_fcall(&req->lr_req, L9P_2000, sb);
+    sbuf_done(sb);
+
+    L9P_LOG(L9P_DEBUG, "%s", sbuf_data(sb));
+    sbuf_delete(sb);
+
     req->lr_tag = req->lr_req.hdr.tag;
 
     for (i = 0; i < N(l9p_handlers); i++) {
@@ -81,6 +96,7 @@ l9p_dispatch_request(struct l9p_request *req)
         }
     }
 
+    L9P_LOG(L9P_WARNING, "unknown request of type %d", req->lr_req.hdr.type);
     l9p_respond(req, L9P_ENOFUNC);
 }
 
@@ -88,19 +104,12 @@ void
 l9p_respond(struct l9p_request *req, const char *error)
 {
     struct l9p_connection *conn = req->lr_conn;
-    struct l9p_message msg;
-    void *buf = malloc(1024 * 1024);
-
-    msg.lm_buffer = buf;
-    msg.lm_pos = buf;
-    msg.lm_end = buf + (1024 * 1024);
-    msg.lm_mode = L9P_PACK;
+    struct sbuf *sb = sbuf_new_auto();
+    size_t iosize;
 
     switch (req->lr_req.hdr.type) {
-    case L9P_TVERSION:
-        break;
-
-    case L9P_TWALK:
+    case L9P_TCLUNK:
+        l9p_connection_remove_fid(conn, req->lr_fid);
         break;
     }
 
@@ -113,43 +122,66 @@ l9p_respond(struct l9p_request *req, const char *error)
         req->lr_resp.error.ename = error;
     }
 
-    if (l9p_pufcall(&msg, &req->lr_resp) != 0) {
+    l9p_describe_fcall(&req->lr_resp, L9P_2000, sb);
+    sbuf_done(sb);
 
+    L9P_LOG(L9P_DEBUG, "%s", sbuf_data(sb));
+    sbuf_delete(sb);    
+
+    if (l9p_pufcall(&req->lr_resp_msg, &req->lr_resp) != 0) {
+        L9P_LOG(L9P_ERROR, "cannot pack response");
+        return;
     }
 
-    conn->lc_send_request(msg.lm_buffer, msg.lm_pos - msg.lm_buffer,
-        conn->lc_send_request_aux);
+    iosize = req->lr_resp_msg.lm_size;
+
+    /* Include I/O size in calculation for Rread response */
+    if (req->lr_resp.hdr.type == L9P_RREAD)
+        iosize += req->lr_resp.io.count;
+
+    conn->lc_send_response(req, req->lr_resp_msg.lm_iov, req->lr_resp_msg.lm_niov,
+        iosize, conn->lc_send_response_aux);
 }
 
 int
 l9p_pack_stat(struct l9p_request *req, struct l9p_stat *st)
 {
-    struct l9p_message msg;
+    struct l9p_connection *conn = req->lr_conn;
+    struct l9p_message *msg = &req->lr_readdir_msg;
     uint16_t size = l9p_sizeof_stat(st);
 
+    if (msg->lm_size == 0) {
+        /* Initialize message */
+        msg->lm_mode = L9P_PACK;
+        msg->lm_niov = req->lr_data_niov;
+        memcpy(msg->lm_iov, req->lr_data_iov, sizeof(struct iovec) * req->lr_data_niov);
+    }
+
+    if (l9p_pustat(msg, st) < 0)
+        return (-1);
+
     req->lr_resp.io.count += size;
-    req->lr_resp.io.data = realloc(req->lr_resp.io.data,
-        req->lr_resp.io.count);
-
-    msg.lm_buffer = req->lr_resp.io.data + req->lr_resp.io.count - size;
-    msg.lm_pos = req->lr_resp.io.data + req->lr_resp.io.count - size;
-    msg.lm_end = req->lr_resp.io.data + req->lr_resp.io.count;
-    msg.lm_mode = L9P_PACK;
-
-    l9p_pustat(&msg, st);
+    return (0);
 }
 
 static void
 l9p_dispatch_tversion(struct l9p_request *req)
 {
+    struct l9p_connection *conn = req->lr_conn;
+    enum l9p_version remote_version;
+
     if (!strcmp(req->lr_req.version.version, "9P"))
         req->lr_resp.version.version = "9P";
     else if (!strcmp(req->lr_req.version.version, "9P2000"))
         req->lr_resp.version.version = "9P2000";
+    else if (!strcmp(req->lr_req.version.version, "9P2000.u"))
+        req->lr_resp.version.version = "9P2000.u";
     else
         req->lr_resp.version.version = "unknown";
 
-    req->lr_resp.version.msize = 8192;
+    conn->lc_msize = MIN(req->lr_req.version.msize, conn->lc_msize);
+    conn->lc_max_io_size = conn->lc_msize - 24;
+    req->lr_resp.version.msize = conn->lc_msize;
     l9p_respond(req, NULL);
 }
 
@@ -158,11 +190,7 @@ l9p_dispatch_tattach(struct l9p_request *req)
 {
     struct l9p_connection *conn = req->lr_conn;
 
-    req->lr_fid = malloc(sizeof(struct l9p_openfile));
-    req->lr_fid->lo_fid = req->lr_req.tcreate.hdr.fid;
-    req->lr_fid->lo_conn = conn;
-    LIST_INSERT_HEAD(&conn->lc_files, req->lr_fid, lo_link);
-
+    req->lr_fid = l9p_connection_alloc_fid(conn, req->lr_req.hdr.fid);
     conn->lc_server->ls_backend->attach(conn->lc_server->ls_backend->softc, req);
 }
 
@@ -171,13 +199,26 @@ l9p_dispatch_tclunk(struct l9p_request *req)
 {
     struct l9p_connection *conn = req->lr_conn;
 
+    req->lr_fid = l9p_connection_find_fid(conn, req->lr_req.hdr.fid);
+    if (!req->lr_fid) {
+        l9p_respond(req, L9P_ENOFID);
+        return;
+    }
+
     conn->lc_server->ls_backend->clunk(conn->lc_server->ls_backend->softc, req);
 }
 
 static void
 l9p_dispatch_tflush(struct l9p_request *req)
 {
+    struct l9p_connection *conn = req->lr_conn;
 
+    if (!conn->lc_server->ls_backend->flush) {
+        l9p_respond(req, L9P_ENOFUNC);
+        return;
+    }
+
+    conn->lc_server->ls_backend->flush(conn->lc_server->ls_backend->softc, req);
 }
 
 static void
@@ -187,15 +228,11 @@ l9p_dispatch_tcreate(struct l9p_request *req)
     struct l9p_openfile *fid;
 
     if (l9p_connection_find_fid(conn, req->lr_req.tcreate.hdr.fid) != NULL) {
-        l9p_respond(req, "x");
+        l9p_respond(req, L9P_ENOFID);
         return;
     }
 
-    fid = malloc(sizeof(struct l9p_openfile));
-    fid->lo_fid = req->lr_req.tcreate.hdr.fid;
-    fid->lo_conn = conn;
-    LIST_INSERT_HEAD(&conn->lc_files, fid, lo_link);
-
+    req->lr_fid = l9p_connection_alloc_fid(conn, req->lr_req.tattach.afid);
     conn->lc_server->ls_backend->create(conn->lc_server->ls_backend->softc, req);
 }
 
@@ -231,6 +268,9 @@ l9p_dispatch_tread(struct l9p_request *req)
         return;
     }
 
+    l9p_seek_iov(req->lr_resp_msg.lm_iov, req->lr_resp_msg.lm_niov,
+        req->lr_data_iov, &req->lr_data_niov, 11);
+
     conn->lc_server->ls_backend->read(conn->lc_server->ls_backend->softc, req);
 }
 
@@ -246,7 +286,18 @@ l9p_dispatch_tstat(struct l9p_request *req)
     struct l9p_connection *conn = req->lr_conn;
     struct l9p_openfile *fid;
 
+    req->lr_fid = l9p_connection_find_fid(conn, req->lr_req.twalk.hdr.fid);
+    if (!req->lr_fid) {
+        l9p_respond(req, L9P_ENOFID);
+        return;
+    }
 
+    if (!conn->lc_server->ls_backend->stat) {
+        l9p_respond(req, L9P_ENOFUNC);
+        return;
+    }
+
+    conn->lc_server->ls_backend->stat(conn->lc_server->ls_backend->softc, req);
 }
 
 static void
@@ -262,10 +313,11 @@ l9p_dispatch_twalk(struct l9p_request *req)
     }
 
     if (req->lr_req.twalk.hdr.fid != req->lr_req.twalk.newfid) {
-        req->lr_newfid = malloc(sizeof(struct l9p_openfile));
-        req->lr_newfid->lo_fid = req->lr_req.twalk.newfid;
-        req->lr_newfid->lo_conn = conn;
-        LIST_INSERT_HEAD(&conn->lc_files, req->lr_newfid, lo_link);
+        req->lr_newfid = l9p_connection_alloc_fid(conn, req->lr_req.twalk.newfid);
+        if (req->lr_newfid == NULL) {
+            l9p_respond(req, L9P_ENOFID);
+            return;
+        }
     }
 
     if (!conn->lc_server->ls_backend->walk) {
diff --git a/transport/socket.c b/transport/socket.c
index ec2af63..f746288 100644
--- a/transport/socket.c
+++ b/transport/socket.c
@@ -33,6 +33,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/event.h>
+#include <sys/uio.h>
 #include <netdb.h>
 #include "../lib9p.h"
 #include "../log.h"
@@ -48,7 +49,10 @@ struct l9p_socket_softc
 };
 
 static int l9p_socket_readmsg(struct l9p_socket_softc *, void **, size_t *);
-static void l9p_socket_sendmsg(void *, size_t, void *);
+static int l9p_socket_get_response_buffer(struct l9p_request *,
+    struct iovec *, size_t *, void *);
+static int l9p_socket_send_response(struct l9p_request *, const struct iovec *,
+    const size_t, const size_t, void *);
 static void *l9p_socket_thread(void *);
 static int xread(int, void *, size_t);
 static int xwrite(int, void *, size_t);
@@ -105,7 +109,7 @@ l9p_start_server(struct l9p_server *server, const char *host, const char *port)
 			    &client_addr_len);
 
 			if (news < 0) {
-				l9p_logf(L9P_WARNING, "accept(): %s", strerror(errno));
+				L9P_LOG(L9P_WARNING, "accept(): %s", strerror(errno));
 				continue;
 			}
 
@@ -130,20 +134,22 @@ l9p_socket_accept(struct l9p_server *server, int conn_fd,
 	    NI_MAXSERV, NI_NUMERICHOST | NI_NUMERICSERV);
 
 	if (err != 0) {
-		l9p_logf(L9P_WARNING, "cannot look up client name: %s",
+		L9P_LOG(L9P_WARNING, "cannot look up client name: %s",
 		    gai_strerror(err));
 	} else
-		l9p_logf(L9P_INFO, "new connection from %s:%s", host, serv);
+		L9P_LOG(L9P_INFO, "new connection from %s:%s", host, serv);
 
 	if (l9p_connection_init(server, &conn) != 0) {
-		l9p_logf(L9P_ERROR, "cannot create new connection");
+		L9P_LOG(L9P_ERROR, "cannot create new connection");
+		return;
 	}
 
-	sc = malloc(sizeof(sc));
+	sc = calloc(1, sizeof(sc));
 	sc->ls_conn = conn;
 	sc->ls_fd = conn_fd;
 
-	l9p_connection_on_send_request(conn, l9p_socket_sendmsg, sc);
+	l9p_connection_on_send_response(conn, l9p_socket_send_response, sc);
+	l9p_connection_on_get_response_buffer(conn, l9p_socket_get_response_buffer, sc);
 	pthread_create(&sc->ls_thread, NULL, l9p_socket_thread, sc);
 }
 
@@ -151,6 +157,7 @@ static void *
 l9p_socket_thread(void *arg)
 {	
 	struct l9p_socket_softc *sc = (struct l9p_socket_softc *)arg;
+	struct iovec iov;
 	void *buf;
 	size_t length;
 
@@ -158,10 +165,12 @@ l9p_socket_thread(void *arg)
 		if (l9p_socket_readmsg(sc, &buf, &length) != 0)
 			break;
 
-		l9p_connection_recv(sc->ls_conn, buf, length);
+		iov.iov_base = buf;
+		iov.iov_len = length;
+		l9p_connection_recv(sc->ls_conn, &iov, 1, NULL);
 	}
 
-	l9p_logf(L9P_INFO, "connection closed");
+	L9P_LOG(L9P_INFO, "connection closed");
 	return (NULL);
 }
 
@@ -169,46 +178,63 @@ static int
 l9p_socket_readmsg(struct l9p_socket_softc *sc, void **buf, size_t *size)
 {
 	uint32_t msize;
+	uint32_t toread;
 	void *buffer;
 	int fd = sc->ls_fd;
 
-	if (xread(fd, &msize, sizeof(uint32_t)) != sizeof(uint32_t)) {
-		l9p_logf(L9P_ERROR, "short read: %s", strerror(errno));
+	buffer = malloc(sizeof(uint32_t));
+
+	if (xread(fd, buffer, sizeof(uint32_t)) != sizeof(uint32_t)) {
+		L9P_LOG(L9P_ERROR, "short read: %s", strerror(errno));
 		return (-1);
 	}
 
-	msize -= sizeof(msize);
-	buffer = malloc(msize);
+	msize = *(uint32_t *)buffer;
+	toread = msize - sizeof(uint32_t);
+	buffer = realloc(buffer, msize);
 
-	if (xread(fd, buffer, msize) != msize) {
-		l9p_logf(L9P_ERROR, "short read: %s", strerror(errno));
+	if (xread(fd, buffer + sizeof(uint32_t), toread) != toread) {
+		L9P_LOG(L9P_ERROR, "short read: %s", strerror(errno));
 		return (-1);
 	}
 
 	*size = msize;
 	*buf = buffer;
-	l9p_logf(L9P_INFO, "%p: read complete message, buf=%p size=%d", sc->ls_conn, buffer, msize);
+	L9P_LOG(L9P_INFO, "%p: read complete message, buf=%p size=%d", sc->ls_conn, buffer, msize);
 
 	return (0);
 }
 
-static void
-l9p_socket_sendmsg(void *buf, size_t len, void *arg)
+static int
+l9p_socket_get_response_buffer(struct l9p_request *req, struct iovec *iov,
+    size_t *niovp, void *arg)
+{
+	size_t size = req->lr_conn->lc_msize;
+	void *buf;
+
+	buf = malloc(size);
+	iov[0].iov_base = buf;
+	iov[0].iov_len = size;
+
+	*niovp = 1;
+	return (0);
+}
+
+static int
+l9p_socket_send_response(struct l9p_request *req, const struct iovec *iov,
+    const size_t niov, const size_t iolen, void *arg)
 {
 	struct l9p_socket_softc *sc = (struct l9p_socket_softc *)arg;
-	uint32_t msize = (uint32_t)len + sizeof(uint32_t);
 
-	l9p_logf(L9P_DEBUG, "%p: sending reply, buf=%p, size=%d", arg, buf, len);
+	L9P_LOG(L9P_DEBUG, "%p: sending reply, buf=%p, size=%d", arg,
+	    iov[0].iov_base, iolen);
 
-	if (xwrite(sc->ls_fd, &msize, sizeof(uint32_t)) != sizeof(uint32_t)) {
-		l9p_logf(L9P_ERROR, "short write: %s", strerror(errno));
-		return;
+	if (xwrite(sc->ls_fd, iov[0].iov_base, iolen) != iolen) {
+		L9_LOG(L9P_ERROR, "short write: %s", strerror(errno));
+		return (-1);
 	}
 
-	if (xwrite(sc->ls_fd, buf, len) != len) {
-		l9p_logf(L9P_ERROR, "short write: %s", strerror(errno));
-		return;
-	}
+	return (0);
 }
 
 static int
diff --git a/utils.c b/utils.c
new file mode 100644
index 0000000..fa8cf01
--- /dev/null
+++ b/utils.c
@@ -0,0 +1,249 @@
+/*
+ * Copyright 2016 Jakub Klama <jceel@FreeBSD.org>
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted providing that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <stdio.h>
+#include <assert.h>
+#include <sys/param.h>
+#include <sys/uio.h>
+#include <sys/sbuf.h>
+#include "lib9p.h"
+#include "fcall.h"
+
+static const char *ftype_names[] = {
+    "Tversion",
+    "Rversion",
+    "Tauth",
+    "Rauth",
+    "Tattach",
+    "Rattach",
+    "Terror",
+    "Rerror",
+    "Tflush",
+    "Rflush",
+    "Twalk",
+    "Rwalk",
+    "Topen",
+    "Ropen",
+    "Tcreate",
+    "Rcreate",
+    "Tread",
+    "Rread",
+    "Twrite",
+    "Rwrite",
+    "Tclunk",
+    "Rclunk",
+    "Tremove",
+    "Rremove",
+    "Tstat",
+    "Rstat",
+    "Twstat",
+    "Rwstat"
+};
+
+void
+l9p_seek_iov(struct iovec *iov1, size_t niov1, struct iovec *iov2,
+    size_t *niov2, size_t seek)
+{
+    size_t remainder = 0;
+    size_t left = seek;
+    int i, j;
+
+    for (i = 0; i < niov1; i++) {
+        size_t toseek = MIN(left, iov1[i].iov_len);
+        left -= toseek;
+
+        if (toseek == iov1[i].iov_len)
+            continue;
+
+        if (left == 0) {
+            remainder = toseek;
+            break;
+        }
+    }
+
+    for (j = i; j < niov1; j++) {
+        iov2[j - i].iov_base = iov1[j].iov_base + remainder;
+        iov2[j - i].iov_len = iov1[j].iov_len - remainder;
+        remainder = 0;
+    }
+
+    *niov2 = j - i;
+}
+
+int
+l9p_truncate_iov(struct iovec *iov, size_t niov, size_t length)
+{
+    int i;
+    size_t done = 0;
+
+    for (i = 0; i < niov; i++) {
+        size_t toseek = MIN(length - done, iov[i].iov_len);
+        done += toseek;
+
+        if (toseek < iov[i].iov_len) {
+            iov[i].iov_len = toseek;
+            return (i + 1);
+        }
+    }
+
+    return (niov);
+}
+
+void
+l9p_describe_qid(struct l9p_qid *qid, struct sbuf *sb)
+{
+
+    assert(qid != NULL);
+    assert(sb != NULL);
+
+    sbuf_printf(sb, "<0x%02x,%u,0x%016llx>", qid->type, qid->version,
+        qid->path);
+}
+
+void
+l9p_describe_stat(struct l9p_stat *st, struct sbuf *sb)
+{
+
+    assert(st != NULL);
+    assert(sb != NULL);
+
+    sbuf_printf(sb, "type=0x%04x dev=%d name=\"%s\" uid=\"%s\"",
+        st->type, st->dev, st->name, st->uid);
+}
+
+void
+l9p_describe_fcall(union l9p_fcall *fcall, enum l9p_version version,
+    struct sbuf *sb)
+{
+    uint8_t type;
+    int i;
+
+    assert(fcall != NULL);
+    assert(sb != NULL);
+    assert(version <= L9P_2000L && version >= L9P_2000);
+
+    type = fcall->hdr.type;
+
+    if (type < 100 || type > 127) {
+        sbuf_printf(sb, "<unknown request %d> tag=%d", type,
+            fcall->hdr.tag);
+        return;
+    }
+
+    sbuf_printf(sb, "%s tag=%d", ftype_names[type - L9P_TVERSION],
+        fcall->hdr.tag);
+
+    switch (type) {
+    case L9P_TVERSION:
+    case L9P_RVERSION:
+        sbuf_printf(sb, " version=\"%s\" msize=%d", fcall->version.version,
+            fcall->version.msize);
+        return;
+    case L9P_TAUTH:
+        sbuf_printf(sb, "afid=%d uname=\"%s\" aname=\"%s\"", fcall->hdr.fid,
+            fcall->tauth.uname, fcall->tauth.aname);
+        return;
+    case L9P_TATTACH:
+        sbuf_printf(sb, " fid=%d afid=%d uname=\"%s\" aname=\"%s\"",
+            fcall->hdr.fid, fcall->tattach.afid, fcall->tattach.uname,
+            fcall->tattach.aname);
+        return;
+    case L9P_TFLUSH:
+        sbuf_printf(sb, " oldtag=%d", fcall->tflush.oldtag);
+        return;
+    case L9P_TWALK:
+        sbuf_printf(sb, " fid=%d newfid=%d wname=\"", fcall->hdr.fid,
+            fcall->twalk.newfid);
+
+        for (i = 0; i < fcall->twalk.nwname; i++) {
+            sbuf_printf(sb, "%s", fcall->twalk.wname[i]);
+            if (i != fcall->twalk.nwname - 1)
+                sbuf_printf(sb, "/");
+        }
+        sbuf_printf(sb, "\"");
+        return;
+    case L9P_RWALK:
+        sbuf_printf(sb, " wqid=");
+        for (i = 0; i < fcall->rwalk.nwqid; i++) {
+            l9p_describe_qid(&fcall->rwalk.wqid[i], sb);
+            if (i != fcall->rwalk.nwqid - 1)
+                sbuf_printf(sb, ",");
+        }
+
+        return;
+    case L9P_TOPEN:
+        sbuf_printf(sb, " fid=%d mode=%d", fcall->hdr.fid,
+            fcall->tcreate.mode);
+
+        return;
+    case L9P_ROPEN:
+        sbuf_printf(sb, " qid=");
+        l9p_describe_qid(&fcall->ropen.qid, sb);
+        sbuf_printf(sb, " iounit=%d", fcall->ropen.iounit);
+        return;
+    case L9P_TCREATE:
+        sbuf_printf(sb, " fid=%d name=\"%s\" perm=0x%08x mode=%d", 
+            fcall->hdr.fid, fcall->tcreate.name, fcall->tcreate.perm,
+            fcall->tcreate.mode);
+        return;
+    case L9P_RCREATE:
+        return;
+    case L9P_TREAD:
+        sbuf_printf(sb, " fid=%d offset=%lu count=%u", fcall->hdr.fid,
+            fcall->io.offset, fcall->io.count);
+        return;
+ 
+    case L9P_RREAD:
+    case L9P_RWRITE:
+        sbuf_printf(sb, " count=%d", fcall->io.count);
+        return;
+    case L9P_TWRITE:
+        sbuf_printf(sb, " fid=%d offset=%lu count=%u", fcall->hdr.fid,
+            fcall->io.offset, fcall->io.count);
+        return;
+    case L9P_TCLUNK:
+        sbuf_printf(sb, " fid=%d ", fcall->hdr.fid);
+        return;
+    case L9P_TREMOVE:
+        sbuf_printf(sb, " fid=%d", fcall->hdr.fid);
+        return;
+    case L9P_RREMOVE:
+        return;
+    case L9P_TSTAT:
+        sbuf_printf(sb, " fid=%d", fcall->hdr.fid);
+        return;
+    case L9P_RSTAT:
+        sbuf_printf(sb, " ");
+        l9p_describe_stat(&fcall->rstat.stat, sb);
+        return;
+    case L9P_TWSTAT:
+        sbuf_printf(sb, " fid=%d", fcall->hdr.fid);
+        return;
+    case L9P_RWSTAT:
+        return;
+    }
+ }