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MFC r1.81

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Revert r1.11.2.38 as the ethernet header was inadvertently stripped from ARP
 packets. Reimplement this correctly and use a sysctl that defaults to off so
 the user doesnt get any suprises if ipfw blocks the ARP packet.

Approved by:	re (hrs)
This commit is contained in:
thompsa 2006-09-25 04:01:20 +00:00
parent 2343d2afdf
commit 472fe3f9c1
1 changed files with 36 additions and 14 deletions
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50
sys/net/if_bridge.c
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@ -277,8 +277,11 @@ static int pfil_onlyip = 1; /* only pass IP[46] packets when pfil is enabled */
static int pfil_bridge = 1; /* run pfil hooks on the bridge interface */
static int pfil_member = 1; /* run pfil hooks on the member interface */
static int pfil_ipfw = 0; /* layer2 filter with ipfw */
static int pfil_ipfw_arp = 0; /* layer2 filter with ipfw */
SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_onlyip, CTLFLAG_RW,
&pfil_onlyip, 0, "Only pass IP packets when pfil is enabled");
SYSCTL_INT(_net_link_bridge, OID_AUTO, ipfw_arp, CTLFLAG_RW,
&pfil_ipfw_arp, 0, "Filter ARP packets through IPFW layer2");
SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_bridge, CTLFLAG_RW,
&pfil_bridge, 0, "Packet filter on the bridge interface");
SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_member, CTLFLAG_RW,
@ -2579,6 +2582,37 @@ bridge_pfil(struct mbuf **mp, struct ifnet *bifp, struct ifnet *ifp, int dir)
}
}
/*
* If we're trying to filter bridge traffic, don't look at anything
* other than IP and ARP traffic. If the filter doesn't understand
* IPv6, don't allow IPv6 through the bridge either. This is lame
* since if we really wanted, say, an AppleTalk filter, we are hosed,
* but of course we don't have an AppleTalk filter to begin with.
* (Note that since pfil doesn't understand ARP it will pass *ALL*
* ARP traffic.)
*/
switch (ether_type) {
case ETHERTYPE_ARP:
case ETHERTYPE_REVARP:
if (pfil_ipfw_arp == 0)
return (0); /* Automatically pass */
break;
case ETHERTYPE_IP:
#ifdef INET6
case ETHERTYPE_IPV6:
#endif /* INET6 */
break;
default:
/*
* Check to see if the user wants to pass non-ip
* packets, these will not be checked by pfil(9) and
* passed unconditionally so the default is to drop.
*/
if (pfil_onlyip)
goto bad;
}
/* Strip off the Ethernet header and keep a copy. */
m_copydata(*mp, 0, ETHER_HDR_LEN, (caddr_t) &eh2);
m_adj(*mp, ETHER_HDR_LEN);
@ -2651,14 +2685,9 @@ ipfwpass:
error = 0;
/*
* Run the packet through pfil. Note that since pfil doesn't understand
* ARP it will pass all ARP traffic.
* Run the packet through pfil
*/
switch (ether_type) {
case ETHERTYPE_ARP:
case ETHERTYPE_REVARP:
return (0); /* Automatically pass */
case ETHERTYPE_IP:
/*
* before calling the firewall, swap fields the same as
@ -2750,14 +2779,7 @@ ipfwpass:
break;
#endif
default:
/*
* Check to see if the user wants to pass non-ip
* packets.
*/
if (pfil_onlyip) {
error = -1;
goto bad;
}
error = 0;
break;
}