lkml.org 
[lkml]   [2004]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] [RFC] Support for wccp version 1 and 2 in ip_gre.c
Replying to Lincoln Dale:
> >From what I observe, netfilter hooks *are* called for unwrapped packets.
> >Either for usual IP packets passed from GRE tunnel, or for demangled
> >wccp packets.
>
> you probably want to ensure that the order of netfilter events are:

Basically all surroinding stuff was untouched. I just enabled further
processing (by kernel IP stack) of GRE-WCCP encapsulated packets.

> 1. [packet comes in]
> 2. netfilter INPUT
> 3. [GRE decap]
> 4. [addressed to us?]
> Yes => netfilter INPUT
> No => netfilter FORWARD
>
> i don't think that both (2) and (4) are done.

I think (2) is done before ipgre_rcv, and (4) is done because after
decapsulation
skb->dev = tunnel->dev;
netif_rx(skb);
this packet reenters the building from matched gre interface.

> also just a minor nit: not all WCCP needs to be GRE-encoded; on
> high-performance switch/router platforms, only a layer-2 rewrite of the dst
> MAC addr is used instead of a layer-3 GRE tunnel. you may want the comment
> at line 609 to explicitly mention "WCCPv1 and WCCPv2 GRE Forwarding mode".

Yes I know this :) L2 case do not need any extra processing, but not
all routers support it. For example, my 4500 don't.

Here is updated patch with if(1) removed and comment changed.

diff -urN /usr/src/linux-2.6.8-1.521/include/linux/if_ether.h linux-2.6.8-1.521wccp/include/linux/if_ether.h
--- /usr/src/linux-2.6.8-1.521/include/linux/if_ether.h 2004-08-14 09:37:15.000000000 +0400
+++ linux-2.6.8-1.521wccp/include/linux/if_ether.h 2004-09-13 08:51:02.000000000 +0400
@@ -59,6 +59,8 @@
#define ETH_P_8021Q 0x8100 /* 802.1Q VLAN Extended Header */
#define ETH_P_IPX 0x8137 /* IPX over DIX */
#define ETH_P_IPV6 0x86DD /* IPv6 over bluebook */
+#define ETH_P_WCCP 0x883E /* Web-cache coordination protocol
+ * defined in draft-wilson-wrec-wccp-v2-00.txt */
#define ETH_P_PPP_DISC 0x8863 /* PPPoE discovery messages */
#define ETH_P_PPP_SES 0x8864 /* PPPoE session messages */
#define ETH_P_MPLS_UC 0x8847 /* MPLS Unicast traffic */
diff -urN /usr/src/linux-2.6.8-1.521/net/ipv4/ip_gre.c linux-2.6.8-1.521wccp/net/ipv4/ip_gre.c
--- /usr/src/linux-2.6.8-1.521/net/ipv4/ip_gre.c 2004-08-14 09:37:37.000000000 +0400
+++ linux-2.6.8-1.521wccp/net/ipv4/ip_gre.c 2004-09-15 00:03:45.586135760 +0400
@@ -605,13 +605,23 @@
if ((tunnel = ipgre_tunnel_lookup(iph->saddr, iph->daddr, key)) != NULL) {
secpath_reset(skb);

+ skb->protocol = *(u16*)(h + 2);
+ /* WCCP version 1 and 2 (in GRE forwarding mode) protocol decoding.
+ * - Change protocol to IP
+ * - When dealing with WCCPv2, skip extra 4 bytes in GRE header
+ */
+ if ((flags == 0) && (skb->protocol == __constant_htons(ETH_P_WCCP))) {
+ skb->protocol = __constant_htons(ETH_P_IP);
+ if ((*(h + offset) & 0xF0) != 0x40)
+ offset += 4;
+ }
+
skb->mac.raw = skb->nh.raw;
skb->nh.raw = __pskb_pull(skb, offset);
memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
if (skb->ip_summed == CHECKSUM_HW)
skb->csum = csum_sub(skb->csum,
csum_partial(skb->mac.raw, skb->nh.raw-skb->mac.raw, 0));
- skb->protocol = *(u16*)(h + 2);
skb->pkt_type = PACKET_HOST;
#ifdef CONFIG_NET_IPGRE_BROADCAST
if (MULTICAST(iph->daddr)) {
--
Paul P 'Stingray' Komkoff Jr // http://stingr.net/key <- my pgp key
This message represents the official view of the voices in my head
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2005-03-22 14:06    [from the cache]
©2003-2011 Jasper Spaans