[src/trunk]: src/sys/net/npf Simplify the pointer handling. Set *mp = NULL at...

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

details:   https://anonhg.NetBSD.org/src/rev/e379726caba9
branches:  trunk
changeset: 991359:e379726caba9
user:      maxv <maxv%NetBSD.org@localhost>
date:      Tue Jul 10 15:25:01 2018 +0000

description:
Simplify the pointer handling. Set *mp = NULL at the beginning of the
function. In npf_reassembly, pass a simple boolean instead of a ** mbuf
pointer. Add a KASSERT for IPv4, we don't want (error && !m). Remove
the 'fastout' label, use 'out'.

diffstat:

 sys/net/npf/npf_handler.c |  50 ++++++++++++++++++++++++----------------------
 1 files changed, 26 insertions(+), 24 deletions(-)

diffs (163 lines):

diff -r 70af8a562a98 -r e379726caba9 sys/net/npf/npf_handler.c
--- a/sys/net/npf/npf_handler.c Tue Jul 10 15:12:29 2018 +0000
+++ b/sys/net/npf/npf_handler.c Tue Jul 10 15:25:01 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: npf_handler.c,v 1.41 2018/07/10 14:04:07 maxv Exp $    */
+/*     $NetBSD: npf_handler.c,v 1.42 2018/07/10 15:25:01 maxv Exp $    */
 
 /*-
  * Copyright (c) 2009-2013 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
 
 #ifdef _KERNEL
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: npf_handler.c,v 1.41 2018/07/10 14:04:07 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: npf_handler.c,v 1.42 2018/07/10 15:25:01 maxv Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -70,25 +70,25 @@
 #endif
 
 static int
-npf_reassembly(npf_t *npf, npf_cache_t *npc, struct mbuf **mp)
+npf_reassembly(npf_t *npf, npf_cache_t *npc, bool *mff)
 {
        nbuf_t *nbuf = npc->npc_nbuf;
        int error = EINVAL;
+       struct mbuf *m;
+
+       *mff = false;
+       m = nbuf_head_mbuf(nbuf);
 
        /* Reset the mbuf as it may have changed. */
-       *mp = nbuf_head_mbuf(nbuf);
        nbuf_reset(nbuf);
 
        if (npf_iscached(npc, NPC_IP4)) {
                struct ip *ip = nbuf_dataptr(nbuf);
-               error = ip_reass_packet(mp, ip);
+               error = ip_reass_packet(&m, ip);
+               KASSERT(!error || (m != NULL));
        } else if (npf_iscached(npc, NPC_IP6)) {
-               /*
-                * Note: ip6_reass_packet() offset is the start of
-                * the fragment header.
-                */
-               error = ip6_reass_packet(mp, npc->npc_hlen);
-               if (error && *mp == NULL) {
+               error = ip6_reass_packet(&m, npc->npc_hlen);
+               if (error && m == NULL) {
                        memset(nbuf, 0, sizeof(nbuf_t));
                }
        }
@@ -96,9 +96,10 @@
                npf_stats_inc(npf, NPF_STAT_REASSFAIL);
                return error;
        }
-       if (*mp == NULL) {
+       if (m == NULL) {
                /* More fragments should come. */
                npf_stats_inc(npf, NPF_STAT_FRAGMENTS);
+               *mff = true;
                return 0;
        }
 
@@ -106,7 +107,7 @@
         * Reassembly is complete, we have the final packet.
         * Cache again, since layer 4 data is accessible now.
         */
-       nbuf_init(npf, nbuf, *mp, nbuf->nb_ifp);
+       nbuf_init(npf, nbuf, m, nbuf->nb_ifp);
        npc->npc_info = 0;
 
        if (npf_cache_all(npc) & (NPC_IPFRAG|NPC_FMTERR)) {
@@ -132,6 +133,7 @@
        int error, decision, flags;
        uint32_t ntag;
        npf_match_info_t mi;
+       bool mff;
 
        /* QSBR checkpoint. */
        pserialize_checkpoint(npf->qsbr);
@@ -150,6 +152,7 @@
        mi.mi_rid = 0;
        mi.mi_retfl = 0;
 
+       *mp = NULL;
        decision = NPF_DECISION_BLOCK;
        error = 0;
        rp = NULL;
@@ -160,22 +163,19 @@
 
        /* If error on the format, leave quickly. */
        if (flags & NPC_FMTERR) {
-               *mp = nbuf_head_mbuf(&nbuf);
                error = EINVAL;
-               goto fastout;
+               goto out;
        }
 
        /* Determine whether it is an IP fragment. */
        if (__predict_false(flags & NPC_IPFRAG)) {
-               /*
-                * Pass to IPv4/IPv6 reassembly mechanism.
-                */
-               error = npf_reassembly(npf, &npc, mp);
+               /* Pass to IPv4/IPv6 reassembly mechanism. */
+               error = npf_reassembly(npf, &npc, &mff);
                if (error) {
                        goto out;
                }
-               if (*mp == NULL) {
-                       /* More fragments should come; return. */
+               if (mff) {
+                       /* More fragments should come. */
                        return 0;
                }
        }
@@ -250,6 +250,7 @@
                        npf_conn_setpass(con, &mi, rp);
                }
        }
+
 pass:
        decision = NPF_DECISION_PASS;
        KASSERT(error == 0);
@@ -257,6 +258,7 @@
         * Perform NAT.
         */
        error = npf_do_nat(&npc, con, di);
+
 block:
        /*
         * Execute the rule procedure, if any is associated.
@@ -267,9 +269,10 @@
                        npf_conn_release(con);
                }
                npf_rproc_release(rp);
-               *mp = NULL;
+               /* mbuf already freed */
                return 0;
        }
+
 out:
        /*
         * Release the reference on a connection.  Release the reference
@@ -281,7 +284,7 @@
                npf_rproc_release(rp);
        }
 
-       /* Reset mbuf pointer before returning to the caller. */
+       /* Get the new mbuf pointer. */
        if ((*mp = nbuf_head_mbuf(&nbuf)) == NULL) {
                return error ? error : ENOMEM;
        }
@@ -309,7 +312,6 @@
                error = ENETUNREACH;
        }
 
-fastout:
        if (*mp) {
                /* Free the mbuf chain. */
                m_freem(*mp);