Date: Mon, 8 May 2006 20:27:23 +0200 From: Daniel Hartmeier <daniel@benzedrine.cx> To: Adam McDougall <mcdouga9@egr.msu.edu> Cc: Andrew Thompson <thompsa@freebsd.org>, freebsd-pf@freebsd.org Subject: Re: broken ip checksum after frag reassemble of nfs READDIR? Message-ID: <20060508182723.GG9739@insomnia.benzedrine.cx> In-Reply-To: <20060508154929.GS30200@egr.msu.edu> References: <20060402054532.GF17711@egr.msu.edu> <20060404145704.GW2684@insomnia.benzedrine.cx> <20060404153443.GX2684@insomnia.benzedrine.cx> <200604051441.16865.max@love2party.net> <20060405130645.GB5683@insomnia.benzedrine.cx> <20060416053023.GD56603@heff.fud.org.nz> <20060508154929.GS30200@egr.msu.edu>
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On Mon, May 08, 2006 at 11:49:30AM -0400, Adam McDougall wrote:
> Could someone possibly produce a patch to force if_bridge to
> recalculate the checksum on every packet so I can test that as well?
> To me, the extra load on the firewall is less important than breaking
> packets I am trying to pass.
Try the patch below, the first one is against -current and the second
against 6.0-stable. It compiles, but is otherwise untested.
I'm not sure if the potential m_pullup() is needed, but better safe than
sorry. Maybe Andrew can comment.
Daniel
Index: if_bridge.c
===================================================================
RCS file: /pub/tmp/cvs/freebsd/src/sys/net/if_bridge.c,v
retrieving revision 1.59
diff -u -r1.59 if_bridge.c
--- if_bridge.c 29 Apr 2006 05:37:25 -0000 1.59
+++ if_bridge.c 8 May 2006 18:17:40 -0000
@@ -2590,7 +2590,7 @@
static int
bridge_pfil(struct mbuf **mp, struct ifnet *bifp, struct ifnet *ifp, int dir)
{
- int snap, error, i;
+ int snap, error, i, hlen;
struct ether_header *eh1, eh2;
struct ip_fw_args args;
struct ip *ip;
@@ -2787,8 +2787,25 @@
/* Restore ip and the fields ntohs()'d. */
ip = mtod(*mp, struct ip *);
+ if (ip == NULL)
+ goto bad;
+ hlen = ip->ip_hl << 2;
+ if (hlen < sizeof(struct ip))
+ goto bad;
+ if (hlen > (*mp)->m_len) {
+ if ((*mp = m_pullup(*mp, hlen)) == 0)
+ goto bad;
+ ip = mtod(*mp, struct ip *);
+ if (ip == NULL)
+ goto bad;
+ }
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
+ ip->ip_sum = 0;
+ if (hlen == sizeof(struct ip))
+ ip->ip_sum = in_cksum_hdr(ip);
+ else
+ ip->ip_sum = in_cksum(*mp, hlen);
break;
# ifdef INET6
Index: if_bridge.c
===================================================================
RCS file: /pub/tmp/cvs/freebsd/src/sys/net/if_bridge.c,v
retrieving revision 1.11.2.12.2.4
diff -u -r1.11.2.12.2.4 if_bridge.c
--- if_bridge.c 25 Jan 2006 10:01:26 -0000 1.11.2.12.2.4
+++ if_bridge.c 8 May 2006 18:21:03 -0000
@@ -2281,7 +2281,7 @@
static int bridge_pfil(struct mbuf **mp, struct ifnet *bifp,
struct ifnet *ifp, int dir)
{
- int snap, error, i;
+ int snap, error, i, hlen;
struct ether_header *eh1, eh2;
struct ip_fw_args args;
struct ip *ip;
@@ -2459,8 +2459,25 @@
/* Restore ip and the fields ntohs()'d. */
if (*mp != NULL && error == 0) {
ip = mtod(*mp, struct ip *);
+ if (ip == NULL)
+ goto bad;
+ hlen = ip->ip_hl << 2;
+ if (hlen < sizeof(struct ip))
+ goto bad;
+ if (hlen > (*mp)->m_len) {
+ if ((*mp = m_pullup(*mp, hlen)) == 0)
+ goto bad;
+ ip = mtod(*mp, struct ip *);
+ if (ip == NULL)
+ goto bad;
+ }
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
+ ip->ip_sum = 0;
+ if (hlen == sizeof(struct ip))
+ ip->ip_sum = in_cksum_hdr(ip);
+ else
+ ip->ip_sum = in_cksum(*mp, hlen);
}
break;
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