[src/trunk]: src/sys/net bpf can send a packet greater than MCLBYTES (JumboFr...

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

details:   https://anonhg.NetBSD.org/src/rev/062c92f0c317
branches:  trunk
changeset: 465584:062c92f0c317
user:      ryo <ryo%NetBSD.org@localhost>
date:      Fri Nov 29 17:29:31 2019 +0000

description:
bpf can send a packet greater than MCLBYTES (JumboFrame) using multiple mbuf.

diffstat:

 sys/net/bpf.c |  52 +++++++++++++++++++++++++++++-----------------------
 1 files changed, 29 insertions(+), 23 deletions(-)

diffs (95 lines):

diff -r e0b994d3e5e4 -r 062c92f0c317 sys/net/bpf.c
--- a/sys/net/bpf.c     Fri Nov 29 17:20:30 2019 +0000
+++ b/sys/net/bpf.c     Fri Nov 29 17:29:31 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bpf.c,v 1.231 2019/09/13 06:39:29 maxv Exp $   */
+/*     $NetBSD: bpf.c,v 1.232 2019/11/29 17:29:31 ryo Exp $    */
 
 /*
  * Copyright (c) 1990, 1991, 1993
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.231 2019/09/13 06:39:29 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.232 2019/11/29 17:29:31 ryo Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_bpf.h"
@@ -321,7 +321,7 @@
 bpf_movein(struct uio *uio, int linktype, uint64_t mtu, struct mbuf **mp,
           struct sockaddr *sockp)
 {
-       struct mbuf *m;
+       struct mbuf *m, *m0, *n;
        int error;
        size_t len;
        size_t hlen;
@@ -395,15 +395,7 @@
        if (len - hlen > mtu)
                return (EMSGSIZE);
 
-       /*
-        * XXX Avoid complicated buffer chaining ---
-        * bail if it won't fit in a single mbuf.
-        * (Take into account possible alignment bytes)
-        */
-       if (len + align > MCLBYTES)
-               return (EIO);
-
-       m = m_gethdr(M_WAIT, MT_DATA);
+       m0 = m = m_gethdr(M_WAIT, MT_DATA);
        m_reset_rcvif(m);
        m->m_pkthdr.len = (int)(len - hlen);
        if (len + align > MHLEN) {
@@ -415,25 +407,39 @@
        }
 
        /* Insure the data is properly aligned */
-       if (align > 0) {
+       if (align > 0)
                m->m_data += align;
-               m->m_len -= (int)align;
+
+       for (;;) {
+               len = M_TRAILINGSPACE(m);
+               if (len > uio->uio_resid)
+                       len = uio->uio_resid;
+               error = uiomove(mtod(m, void *), len, uio);
+               if (error)
+                       goto bad;
+               m->m_len = len;
+
+               if (uio->uio_resid == 0)
+                       break;
+
+               n = m_get(M_WAIT, MT_DATA);
+               m_clget(n, M_WAIT);     /* if fails, there is no problem */
+               m->m_next = n;
+               m = n;
        }
 
-       error = uiomove(mtod(m, void *), len, uio);
-       if (error)
-               goto bad;
        if (hlen != 0) {
-               memcpy(sockp->sa_data, mtod(m, void *), hlen);
-               m->m_data += hlen; /* XXX */
-               len -= hlen;
+               /* move link level header in the top of mbuf to sa_data */
+               memcpy(sockp->sa_data, mtod(m0, void *), hlen);
+               m0->m_data += hlen;
+               m0->m_len -= hlen;
        }
-       m->m_len = (int)len;
-       *mp = m;
+
+       *mp = m0;
        return (0);
 
 bad:
-       m_freem(m);
+       m_freem(m0);
        return (error);
 }