[src/trunk]: src/sys Add two new mbuf routines:

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b20d68922c37
branches:  trunk
changeset: 545617:b20d68922c37
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat Apr 12 02:49:25 2003 +0000

description:
Add two new mbuf routines:
* m_apply(), which applies a function to each mbuf in chain
  starting at a specified offset, for a specified length.
* m_getptr(), which returns a pointer to the mbuf, as well as
  the offset into that mbuf, corresponding to an offset from
  the beginning of an mbuf chain.

>From OpenBSD, cleaned up slightly by me.

diffstat:

 sys/kern/uipc_mbuf.c |  71 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 sys/sys/mbuf.h       |   9 ++++--
 2 files changed, 75 insertions(+), 5 deletions(-)

diffs (116 lines):

diff -r 8e7793fd1dee -r b20d68922c37 sys/kern/uipc_mbuf.c
--- a/sys/kern/uipc_mbuf.c      Sat Apr 12 02:15:22 2003 +0000
+++ b/sys/kern/uipc_mbuf.c      Sat Apr 12 02:49:25 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uipc_mbuf.c,v 1.65 2003/04/09 18:38:03 thorpej Exp $   */
+/*     $NetBSD: uipc_mbuf.c,v 1.66 2003/04/12 02:49:25 thorpej Exp $   */
 
 /*-
  * Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
@@ -73,7 +73,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uipc_mbuf.c,v 1.65 2003/04/09 18:38:03 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uipc_mbuf.c,v 1.66 2003/04/12 02:49:25 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1022,3 +1022,70 @@
 out:   if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
                m->m_pkthdr.len = totlen;
 }
+
+/*
+ * Apply function f to the data in an mbuf chain starting "off" bytes from the
+ * beginning, continuing for "len" bytes.
+ */
+int
+m_apply(struct mbuf *m, int off, int len,
+    int (*f)(void *, caddr_t, unsigned int), void *arg)
+{
+       unsigned int count;
+       int rval;
+
+       KASSERT(len >= 0);
+       KASSERT(off >= 0);
+
+       while (off > 0) {
+               KASSERT(m != NULL);
+               if (off < m->m_len)
+                       break;
+               off -= m->m_len;
+               m = m->m_next;
+       }
+       while (len > 0) {
+               KASSERT(m != NULL);
+               count = min(m->m_len - off, len);
+
+               rval = (*f)(arg, mtod(m, caddr_t) + off, count);
+               if (rval)
+                       return (rval);
+
+               len -= count;
+               off = 0;
+               m = m->m_next;
+       }
+
+       return (0);
+}
+
+/*
+ * Return a pointer to mbuf/offset of location in mbuf chain.
+ */
+struct mbuf *
+m_getptr(struct mbuf *m, int loc, int *off)
+{
+
+       while (loc >= 0) {
+               /* Normal end of search */
+               if (m->m_len > loc) {
+                       *off = loc;
+                       return (m);
+               } else {
+                       loc -= m->m_len;
+
+                       if (m->m_next == NULL) {
+                               if (loc == 0) {
+                                       /* Point at the end of valid data */
+                                       *off = m->m_len;
+                                       return (m);
+                               } else
+                                       return (NULL);
+                       } else
+                               m = m->m_next;
+               }
+       }
+
+       return (NULL);
+}
diff -r 8e7793fd1dee -r b20d68922c37 sys/sys/mbuf.h
--- a/sys/sys/mbuf.h    Sat Apr 12 02:15:22 2003 +0000
+++ b/sys/sys/mbuf.h    Sat Apr 12 02:49:25 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mbuf.h,v 1.80 2003/04/09 18:38:01 thorpej Exp $        */
+/*     $NetBSD: mbuf.h,v 1.81 2003/04/12 02:49:25 thorpej Exp $        */
 
 /*-
  * Copyright (c) 1996, 1997, 1999, 2001 The NetBSD Foundation, Inc.
@@ -807,12 +807,15 @@
 struct mbuf *m_get(int, int);
 struct mbuf *m_getclr(int, int);
 struct mbuf *m_gethdr(int, int);
-struct mbuf *m_prepend(struct mbuf *,int,int);
+struct mbuf *m_prepend(struct mbuf *,int, int);
 struct mbuf *m_pulldown(struct mbuf *, int, int, int *);
 struct mbuf *m_pullup(struct mbuf *, int);
 struct mbuf *m_copyup(struct mbuf *, int, int);
-struct mbuf *m_split(struct mbuf *,int,int);
+struct mbuf *m_split(struct mbuf *,int, int);
+struct mbuf *m_getptr(struct mbuf *, int, int *);
 void   m_adj(struct mbuf *, int);
+int    m_apply(struct mbuf *, int, int,
+               int (*)(void *, caddr_t, unsigned int), void *);
 void   m_cat(struct mbuf *,struct mbuf *);
 #ifdef MBUFTRACE
 void   m_claim(struct mbuf *, struct mowner *);