diff --git a/core-test/app/Makefile b/core-test/app/Makefile
new file mode 100644
index 0000000..c398f8c
--- /dev/null
+++ b/core-test/app/Makefile
@@ -0,0 +1,25 @@
+CC=gcc
+CFLAGS=-Wall -g -Wextra
+LDFLAGS= -pthread
+CFILES=$(wildcard *.c) # CFILES => recompiles everything on a C file change
+EXEC=$(basename $(wildcard *.c))
+SOURCES=$(wildcard ../lib/*.c ../../core/*.c)
+OBJECTS=$(SOURCES:.c=.o)
+TESTS=$(addsuffix .test, $(EXEC))
+
+all: $(SOURCES) $(EXEC)
+
+$(EXEC): $(OBJECTS) $(CFILES)
+	$(CC) $(CFLAGS) $(LDFLAGS) $(OBJECTS) $@.c -lcbor -o $@.bin
+
+.c.o:
+	$(CC) -c $(CFLAGS) $< -o $@
+
+$(TESTS):
+	valgrind --show-leak-kinds=all --leak-check=full -v --track-origins=yes ./$(basename $@)
+
+clean:
+	@-rm $(OBJECTS)
+
+mrproper: clean
+	@-rm *.bin
diff --git a/core-test/app/benchmark_usock-client.c b/core-test/app/benchmark_usock-client.c
new file mode 100644
index 0000000..ef6fd98
--- /dev/null
+++ b/core-test/app/benchmark_usock-client.c
@@ -0,0 +1,59 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+
+#include "../../core/usocket.h"
+
+#define handle_err(fun,msg)\
+    fprintf (stderr, "%s: file %s line %d %s\n", fun, __FILE__, __LINE__, msg);
+
+#define UPATH "/tmp/ipc/usock-path.sock"
+#define MSG "coucou"
+
+int main (int argc, char * argv[])
+{
+
+    argc = argc;
+    argv = argv;
+
+    int fd;
+    size_t msize = BUFSIZ;
+    char *buf = NULL;
+
+    struct timeval t1;
+    struct timeval t2;
+
+    if ( (buf = malloc (BUFSIZ)) == NULL) {
+        handle_err ("main", "malloc");
+        return EXIT_FAILURE;
+    }
+    memset (buf, 0, BUFSIZ);
+
+    if (usock_connect (&fd, UPATH) < 0) {
+        handle_err("main", "usock_listen < 0");
+        return EXIT_FAILURE;
+    }
+
+    gettimeofday (&t1, NULL);
+    if (usock_send (fd, MSG, strlen(MSG)) < 0) {
+        handle_err("main", "usock_send < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_recv (fd, &buf, &msize) < 0) {
+        handle_err("main", "usock_recv < 0");
+        return EXIT_FAILURE;
+    }
+    gettimeofday (&t2, NULL);
+
+    printf ("it took %ld µs to send then recv a message\n"
+            , t2.tv_usec - t1.tv_usec);
+
+    if (usock_close (fd) < 0) {
+        handle_err("main", "usock_close < 0");
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}
diff --git a/core-test/app/benchmark_usock-server.c b/core-test/app/benchmark_usock-server.c
new file mode 100644
index 0000000..a50bd8f
--- /dev/null
+++ b/core-test/app/benchmark_usock-server.c
@@ -0,0 +1,67 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "../../core/usocket.h"
+
+#define handle_err(fun,msg)\
+    fprintf (stderr, "%s: file %s line %d %s\n", fun, __FILE__, __LINE__, msg);
+
+#define UPATH "/tmp/ipc/usock-path.sock"
+
+int main (int argc, char * argv[])
+{
+
+    argc = argc;
+    argv = argv;
+
+    int fd;
+    int pfd;
+    size_t msize = BUFSIZ;
+    char *buf = NULL;
+
+    if ( (buf = malloc (BUFSIZ)) == NULL) {
+        handle_err ("main", "malloc");
+        return EXIT_FAILURE;
+    }
+    memset (buf, 0, BUFSIZ);
+
+    // socket + bind + listen
+    if (usock_init (&fd, UPATH) < 0) {
+        handle_err("main", "usock_init < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_accept (fd, &pfd) < 0) {
+        handle_err("main", "usock_accept < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_recv (pfd, &buf, &msize) < 0) {
+        handle_err("main", "usock_recv < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_send (pfd, buf, msize) < 0) {
+        handle_err("main", "usock_send < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_close (fd) < 0) {
+        handle_err("main", "usock_close fd < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_close (pfd) < 0) {
+        handle_err("main", "usock_close pfd < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_remove (UPATH) < 0) {
+        handle_err("main", "usock_remove < 0");
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}
diff --git a/core-test/app/usock-client.c b/core-test/app/usock-client.c
new file mode 100644
index 0000000..1ce6514
--- /dev/null
+++ b/core-test/app/usock-client.c
@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../../core/usocket.h"
+
+#define handle_err(fun,msg)\
+    fprintf (stderr, "%s: file %s line %d %s\n", fun, __FILE__, __LINE__, msg);
+
+#define UPATH "/tmp/ipc/usock-path.sock"
+#define MSG "coucou"
+
+int main (int argc, char * argv[])
+{
+
+    argc = argc;
+    argv = argv;
+
+    int fd;
+    size_t msize = BUFSIZ;
+    char *buf = NULL;
+
+    if ( (buf = malloc (BUFSIZ)) == NULL) {
+        handle_err ("main", "malloc");
+        return EXIT_FAILURE;
+    }
+    memset (buf, 0, BUFSIZ);
+
+    if (usock_connect (&fd, UPATH) < 0) {
+        handle_err("main", "usock_listen < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_send (fd, MSG, strlen(MSG)) < 0) {
+        handle_err("main", "usock_send < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_recv (fd, &buf, &msize) < 0) {
+        handle_err("main", "usock_recv < 0");
+        return EXIT_FAILURE;
+    }
+
+    printf ("msg recv: %s\n", buf);
+
+    if (usock_close (fd) < 0) {
+        handle_err("main", "usock_close < 0");
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}
diff --git a/core-test/app/usock-server.c b/core-test/app/usock-server.c
new file mode 100644
index 0000000..ce3f1ea
--- /dev/null
+++ b/core-test/app/usock-server.c
@@ -0,0 +1,71 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "../../core/usocket.h"
+
+#define handle_err(fun,msg)\
+    fprintf (stderr, "%s: file %s line %d %s\n", fun, __FILE__, __LINE__, msg);
+
+#define UPATH "/tmp/ipc/usock-path.sock"
+
+int main (int argc, char * argv[])
+{
+
+    argc = argc;
+    argv = argv;
+
+    int fd;
+    int pfd;
+    size_t msize = BUFSIZ;
+    char *buf = NULL;
+
+    if ( (buf = malloc (BUFSIZ)) == NULL) {
+        handle_err ("main", "malloc");
+        return EXIT_FAILURE;
+    }
+    memset (buf, 0, BUFSIZ);
+
+    // socket + bind + listen
+    if (usock_init (&fd, UPATH) < 0) {
+        handle_err("main", "usock_init < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_accept (fd, &pfd) < 0) {
+        handle_err("main", "usock_accept < 0");
+        return EXIT_FAILURE;
+    }
+
+    printf ("new connection\n");
+
+    if (usock_recv (pfd, &buf, &msize) < 0) {
+        handle_err("main", "usock_recv < 0");
+        return EXIT_FAILURE;
+    }
+
+    printf ("msg recv: %s\n", buf);
+
+    if (usock_send (pfd, buf, msize) < 0) {
+        handle_err("main", "usock_send < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_close (fd) < 0) {
+        handle_err("main", "usock_close fd < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_close (pfd) < 0) {
+        handle_err("main", "usock_close pfd < 0");
+        return EXIT_FAILURE;
+    }
+
+    if (usock_remove (UPATH) < 0) {
+        handle_err("main", "usock_remove < 0");
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}
diff --git a/core/communication.c b/core/communication.c
index 1ddaddc..9494a5b 100644
--- a/core/communication.c
+++ b/core/communication.c
@@ -6,11 +6,10 @@
 #include <stdio.h>
 #include <errno.h>
 
-#define LISTEN_BACKLOG 50
 #define handle_error(msg) \
     do { perror(msg); exit(EXIT_FAILURE); } while (0)
 
-void service_path (char *path, const char *name, int index, int version)
+void service_path (char *path, const char *sname, int index, int version)
 {
     memset (path, 0, PATH_MAX);
     snprintf (path, PATH_MAX, "%s/%s-%d-%d", TMPDIR, sname, index, version);
@@ -35,7 +34,7 @@ int srv_init (int argc, char **argv, char **env
     // gets the service path
     service_path (srv->spath, sname, srv->index, srv->version);
 
-    usock_listen (&srv->service_fd, srv->spath);
+    usock_init (&srv->service_fd, srv->spath);
 
     return 0;
 }
@@ -43,12 +42,7 @@ int srv_init (int argc, char **argv, char **env
 int srv_close (struct service *srv)
 {
     usock_close (srv->service_fd);
-
-    if (unlink (srv->spath)) {
-        return 1;
-    }
-
-    return 0;
+    return usock_remove (srv->spath);
 }
 
 int srv_read (const struct service *srv, char ** buf, size_t *msize)
diff --git a/core/communication.h b/core/communication.h
index 3276ec8..d12fcd8 100644
--- a/core/communication.h
+++ b/core/communication.h
@@ -45,7 +45,7 @@ int srv_init (int argc, char **argv, char **env
         , struct service *srv, const char *sname);
 int srv_close (struct service *srv);
 
-int srv_read (const struct service *, char ** buf);
+int srv_read (const struct service *srv, char ** buf, size_t *msize);
 int srv_write (const struct service *, const char * buf, size_t);
 
 // APPLICATION
diff --git a/core/usocket.c b/core/usocket.c
index 5ce720d..4c42e35 100644
--- a/core/usocket.c
+++ b/core/usocket.c
@@ -1,4 +1,8 @@
 #include "usocket.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
 #include <assert.h>
 
 #define handle_err(fun,msg)\
@@ -66,7 +70,7 @@ int usock_connect (int *fd, const char *path)
     struct sockaddr_un my_addr;
     socklen_t peer_addr_size;
 
-    sfd = socket(AF_UNIX, SOCK_STREAM, 0);
+    sfd = socket (AF_UNIX, SOCK_STREAM, 0);
     if (sfd == -1) {
         handle_err ("usock_connect", "sfd == -1");
         return -1;
@@ -86,20 +90,22 @@ int usock_connect (int *fd, const char *path)
     }
 
     *fd = sfd;
+
+    return 0;
 }
 
-int usock_listen (int *fd, const char *path)
+int usock_init (int *fd, const char *path)
 {
     assert (fd != NULL);
     assert (path != NULL);
 
     if (fd == NULL) {
-        handle_err ("usock_listen", "fd == NULL");
+        handle_err ("usock_init", "fd == NULL");
         return -1;
     }
 
     if (path == NULL) {
-        handle_err ("usock_listen", "path == NULL");
+        handle_err ("usock_init", "path == NULL");
         return -1;
     }
 
@@ -107,9 +113,9 @@ int usock_listen (int *fd, const char *path)
     struct sockaddr_un my_addr;
     socklen_t peer_addr_size;
 
-    sfd = socket(AF_UNIX, SOCK_STREAM, 0);
+    sfd = socket (AF_UNIX, SOCK_STREAM, 0);
     if (sfd == -1) {
-        handle_err ("usock_listen", "sfd == -1");
+        handle_err ("usock_init", "sfd == -1");
         return -1;
     }
 
@@ -121,23 +127,47 @@ int usock_listen (int *fd, const char *path)
 
     // TODO FIXME
     // delete the unix socket if already created
-    unlink(my_addr.sun_path);
 
     peer_addr_size = sizeof(struct sockaddr_un);
-    if (bind(sfd, (struct sockaddr *) &my_addr, peer_addr_size) == -1) {
-        handle_err ("usock_listen", "bind == -1");
+
+    if (bind (sfd, (struct sockaddr *) &my_addr, peer_addr_size) == -1) {
+        handle_err ("usock_init", "bind == -1");
         perror("bind()");
         return -1;
     }
 
-    if (listen(sfd, LISTEN_BACKLOG) == -1) {
-        handle_err ("usock_listen", "listen == -1");
+    if (listen (sfd, LISTEN_BACKLOG) == -1) {
+        handle_err ("usock_init", "listen == -1");
         perror("listen()");
         return -1;
     }
 
     *fd = sfd;
 
+    return 0;
+}
+
+int usock_accept (int fd, int *pfd)
+{
+    assert (pfd != NULL);
+
+    if (pfd == NULL) {
+        handle_err ("usock_accept", "pfd == NULL");
+        return -1;
+    }
+
+    struct sockaddr_un peer_addr;
+    memset (&peer_addr, 0, sizeof (struct sockaddr_un));
+    socklen_t peer_addr_size;
+
+    *pfd = accept (fd, (struct sockaddr *) &peer_addr, &peer_addr_size);
+    if (*pfd < 0) {
+        handle_err ("usock_accept", "accept < 0");
+        perror("listen()");
+        return -1;
+    }
+
+    return 0;
 }
 
 int usock_close (int fd)
@@ -150,3 +180,8 @@ int usock_close (int fd)
     }
     return ret;
 }
+
+int usock_remove (const char *path)
+{
+    return unlink (path);
+}
diff --git a/core/usocket.h b/core/usocket.h
index a3b668f..7c61170 100644
--- a/core/usocket.h
+++ b/core/usocket.h
@@ -5,6 +5,8 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 
+#define LISTEN_BACKLOG 128
+
 // same as recv(2)
 int usock_send (int fd, const char *buf, const int m_size);
 
@@ -19,6 +21,17 @@ int usock_close (int fd);
 
 // same as connect(2)
 // if fd == NULL => -1
-int usock_connect (int *fd, const char *path)
+int usock_connect (int *fd, const char *path);
+
+// if not ok => -1
+// if ok => 0
+int usock_init (int *fd, const char *path);
+
+// if not ok => -1
+// if ok => 0
+int usock_accept (int fd, int *pfd);
+
+// same as unlink(2)
+int usock_remove (const char *path);
 
 #endif