[PATCH] uml: slirp and slip driver cleanups and fixes
This patch merges a lot of duplicated code in the slip and slirp drivers,
abstracts out the slip protocol, and makes the slip driver work in 2.6.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/drivers/slip_common.h b/arch/um/drivers/slip_common.h
new file mode 100644
index 0000000..2ae76d8
--- /dev/null
+++ b/arch/um/drivers/slip_common.h
@@ -0,0 +1,104 @@
+#ifndef __UM_SLIP_COMMON_H
+#define __UM_SLIP_COMMON_H
+
+#define BUF_SIZE 1500
+ /* two bytes each for a (pathological) max packet of escaped chars + *
+ * terminating END char + initial END char */
+#define ENC_BUF_SIZE (2 * BUF_SIZE + 2)
+
+/* SLIP protocol characters. */
+#define SLIP_END 0300 /* indicates end of frame */
+#define SLIP_ESC 0333 /* indicates byte stuffing */
+#define SLIP_ESC_END 0334 /* ESC ESC_END means END 'data' */
+#define SLIP_ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
+
+static inline int slip_unesc(unsigned char c, unsigned char *buf, int *pos,
+ int *esc)
+{
+ int ret;
+
+ switch(c){
+ case SLIP_END:
+ *esc = 0;
+ ret=*pos;
+ *pos=0;
+ return(ret);
+ case SLIP_ESC:
+ *esc = 1;
+ return(0);
+ case SLIP_ESC_ESC:
+ if(*esc){
+ *esc = 0;
+ c = SLIP_ESC;
+ }
+ break;
+ case SLIP_ESC_END:
+ if(*esc){
+ *esc = 0;
+ c = SLIP_END;
+ }
+ break;
+ }
+ buf[(*pos)++] = c;
+ return(0);
+}
+
+static inline int slip_esc(unsigned char *s, unsigned char *d, int len)
+{
+ unsigned char *ptr = d;
+ unsigned char c;
+
+ /*
+ * Send an initial END character to flush out any
+ * data that may have accumulated in the receiver
+ * due to line noise.
+ */
+
+ *ptr++ = SLIP_END;
+
+ /*
+ * For each byte in the packet, send the appropriate
+ * character sequence, according to the SLIP protocol.
+ */
+
+ while (len-- > 0) {
+ switch(c = *s++) {
+ case SLIP_END:
+ *ptr++ = SLIP_ESC;
+ *ptr++ = SLIP_ESC_END;
+ break;
+ case SLIP_ESC:
+ *ptr++ = SLIP_ESC;
+ *ptr++ = SLIP_ESC_ESC;
+ break;
+ default:
+ *ptr++ = c;
+ break;
+ }
+ }
+ *ptr++ = SLIP_END;
+ return (ptr - d);
+}
+
+struct slip_proto {
+ unsigned char ibuf[ENC_BUF_SIZE];
+ unsigned char obuf[ENC_BUF_SIZE];
+ int more; /* more data: do not read fd until ibuf has been drained */
+ int pos;
+ int esc;
+};
+
+#define SLIP_PROTO_INIT { \
+ .ibuf = { '\0' }, \
+ .obuf = { '\0' }, \
+ .more = 0, \
+ .pos = 0, \
+ .esc = 0 \
+}
+
+extern int slip_proto_read(int fd, void *buf, int len,
+ struct slip_proto *slip);
+extern int slip_proto_write(int fd, void *buf, int len,
+ struct slip_proto *slip);
+
+#endif