Messages in this thread | | | From | "Zhang haofeng" <> | Subject | sk_buff problem | Date | Thu, 4 Sep 2003 15:42:21 +0800 |
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Dear all, Does somebody have some knowledge about /net/ipv6/sit.c? I try to modify sit.c to cater for my requirements: I want to use IPv4+UDP+IPv6+IPv6 Data to encapsulate IPv6 packets, thus every IPv6 packet will be able to pass through some IPv4 NATs. As you know, sit.c is to encapsulate IPv6 packets in IPv4 payload, so it seems that I only need to add UDP layer between IPv4 header and IPv6 header in the encapsulated packet. But I got problem when I receive an IPv4 UDP packet. I wanna de-encapsulate the packet and send UDP data (which is an IPv6 packet) to IPv6 upper layer protocol use netif_rx( ). But it seems that I can not set the correspondent field in sk_buff struct correctly. In sit.c, line 396, when 6to4 interface receive a IPv4 packet: ***************** if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) goto out; ... skb->mac.raw= skb->nh.raw; skb->nh.raw= skb-> data; ... netif_rx(skb);
So in my modified sit.c, I modify the source code to : ***************** if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) goto out; ... skb->mac.ethernet->h_proto= __constant_htons(0x86DD); skb->nh.raw= skb->data+sizeof(struct udphdr); skb->protocol = __constant_htons(0x86DD); ... netif_rx(skb); ...
The result is, from the debug information, I can see the IPv6 header, the IPv6 data is put in sk_buff structure correctly. But after I cannot use netif_rx() to send this de-encapsulated packet to IPv6 core protocol stack correctly, while the ICMPv4 UDP port unreachable message is sent to the sender. I am confused :( I really appreciate your any kind of help, thanks in advance.....
Zhanghaofeng Sep 3rd, 2003
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