> I read net/ipv4/ipip.c. It seems to me that ipip_rcv() function after
> "unwrapping" tunelled IP packet creates "virtual Ethernet header" and submit
Does it? ipip_rcv() does this:
iph = skb->nh.iph;
skb->mac.raw = skb->nh.raw;
i.e. the "MAC header" pointer of the packet is the same as the IP
header, iow. no MAC header available
skb->nh.raw = skb->data;
Although I don't exactly understand this :-) it does not add a header
memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
this must be cleared before processing the packet
skb->protocol = __constant_htons(ETH_P_IP);
skb->pkt_type = PACKET_HOST;
mark it as an IP packet
read_lock(&ipip_lock);
if ((tunnel = ipip_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) {
tunnel->stat.rx_packets++;
tunnel->stat.rx_bytes += skb->len;
skb->dev = tunnel->dev;
mark the incoming device
dst_release(skb->dst);
skb->dst = NULL;
#ifdef CONFIG_NETFILTER
nf_conntrack_put(skb->nfct);
skb->nfct = NULL;
#ifdef CONFIG_NETFILTER_DEBUG
skb->nf_debug = 0;
#endif
#endif
more clearing of fields / release of resources associated with the packet
ipip_ecn_decapsulate(iph, skb);
handle ECN flags
netif_rx(skb);
The packet as submitted starts with the IP header and the skb pointers
are set up so that the MAC header has zero size.
Olaf
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This archive was generated by hypermail 2b29 : Tue May 15 2001 - 21:00:31 EST