On 7/24/2018 10:59 PM, sougol gheissi wrote:
Hello,
I want to add a short piece of code to the OVS source code so that I
can mark the packet based on some meta data in the packet. I have add
the snippet code below to the /datapath/vport-netdev.c
void netdev_port_receive(struct sk_buff *skb, struct ip_tunnel_info
*tun_info){
struct iphdr *ip_header = (struct iphdr *)skb_network_header(skb);
struct udphdr *udp_header;
if (ip_header->protocol == 17) //UDP protocol
{
udp_header = (struct udphdr *)((__u32 *)ip_header+
ip_header->ihl);
if ((udp_header->dest == 50195)
{
mark =
/setMark/((char*)udp_header,htons(ip_header->tot_len)- 20);
if(mark != -1){
skb->mark = mark;
}
}
}
}
which /setMark/ is an function in the same file. Then I managed my
controller in floodlight to set the rules based on pkt_mark first time
these kind of packets come to the switch. After that I expect packets
to be routed based on that rules and not going to the controller
anymore, however some of them do not hit the rules related to them and
go to the controllers. I have to mention that I made the rules coming
from the controller to last forever. I have some questions here. As
the packet do not hit the rules associated to them, I concluded that
the packets do not get the marks. (Is it right?)
1. Is the vport-netdev.c the right place to add my snippet? Actually I
mean is it the first place I can mangle the packet in kernel?
Probably not - most packets in the kernel arrive at a device receive
function and then get routed
up through the kernel network stack to protocol drivers that take action
on the packet before
sending it on to applications or to be forwarded by some other interface.
2. If no, where should I add my snippet?
Depends on the type of traffic you want to get. For ipv4 you might want
to look at the kernel ../net/ipv4/ip_input.c module.
- Greg
Thanks in advance
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https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
