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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