Hi, yes, I'm aware none of this compiles nor makes sense at this time

include/patty/kiss.h

@@ -32,7 +32,7 @@ patty_kiss_tnc *patty_kiss_tnc_open(const char *device, size_t bufsize);
 void patty_kiss_tnc_close(patty_kiss_tnc *tnc);
 
 ssize_t patty_kiss_read(patty_kiss_tnc *tnc,
-    void *buf, size_t len, int *port);
+    void **buf, int *port);
 
 ssize_t patty_kiss_write(patty_kiss_tnc *tnc,
     const void *buf, size_t len, int port);

src/kiss.c

@@ -1,6 +1,9 @@
-#include <sys/types.h>
+#include <stdlib.h>
-#include <sys/uio.h>
+#include <fcntl.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
 #include <errno.h>
 
 #include <patty/kiss.h>
@@ -11,18 +14,61 @@ enum kiss_flags {
     KISS_ESCAPE = 0x02
 };
 
-ssize_t patty_kiss_read(int fd, void *buf, size_t len, int *port) {
+struct _patty_kiss_tnc {
+    int    fd;
+    size_t size;
+    size_t len;
+    void * buf;
+};
+
+patty_kiss_tnc *patty_kiss_tnc_open(const char *device, size_t bufsize) {
+    patty_kiss_tnc *tnc;
+
+    if ((tnc = malloc(sizeof(*tnc))) == NULL) {
+        goto error_malloc_tnc;
+    }
+
+    if ((tnc->buf = malloc(bufsize)) == NULL) {
+        goto error_malloc_buf;
+    }
+
+    if ((tnc->fd = open(device, O_RDWR)) < 0) {
+        goto error_open;
+    }
+
+    tnc->size = bufsize;
+    tnc->len  = 0;
+
+    return tnc;
+
+error_open:
+    free(tnc->buf);
+
+error_malloc_buf:
+    free(tnc);
+
+error_malloc_tnc:
+    return NULL;
+}
+
+void patty_kiss_tnc_close(patty_kiss_tnc *tnc) {
+    close(tnc->fd);
+    free(tnc->buf);
+    free(tnc);
+}
+
+ssize_t patty_kiss_read(patty_kiss_tnc *tnc, void **frame, int *port) {
     int flags = KISS_NONE;
     size_t i, b = 0;
 
-    if (read(fd, buf, len) < 0) {
+    if (read(tnc->fd, tnc->buf, len) < 0) {
         goto error_io;
     }
 
     *port = 0;
 
     for (i=0; i<len; i++) {
-        unsigned char c = ((char *)buf)[i];
+        unsigned char c = ((char *)tnc->buf)[i];
 
         if ((flags & KISS_FRAME) == 0) {
             if (c == PATTY_KISS_FEND) {
@@ -34,9 +80,9 @@ ssize_t patty_kiss_read(int fd, void *buf, size_t len, int *port) {
 
         if (flags & KISS_ESCAPE) {
             if (c == PATTY_KISS_TFEND) {
-                ((unsigned char *)buf)[b++] = PATTY_KISS_FEND;
+                ((unsigned char *)tnc->buf)[b++] = PATTY_KISS_FEND;
             } else if (c == PATTY_KISS_TFESC) {
-                ((unsigned char *)buf)[b++] = PATTY_KISS_FESC;
+                ((unsigned char *)tnc->buf)[b++] = PATTY_KISS_FESC;
             } else {
                 errno = EIO;
 
@@ -71,7 +117,7 @@ ssize_t patty_kiss_read(int fd, void *buf, size_t len, int *port) {
                 continue;
             }
 
-            ((unsigned char *)buf)[b++] = c;
+            ((unsigned char *)tnc->buf)[b++] = c;
         }
     }
 
@@ -89,7 +135,7 @@ static inline ssize_t write_command(int fd, int command, int port) {
     return write_byte(fd, ((port & 0x0f) << 4) | (command & 0x0f));
 }
 
-ssize_t patty_kiss_write(int fd, const void *buf, size_t len, int port) {
+ssize_t patty_kiss_write(patty_kiss_tnc *tnc, const void *buf, size_t len, int port) {
     size_t i, start = 0, end = 0;
 
     unsigned char escape_fend[2] = { PATTY_KISS_FESC, PATTY_KISS_TFEND };