Re: [dpdk-users] How to change IP and port in packet header and recalculate checksum

[Murad Kablan <Murad.Kablan@Colorado.EDU>]

Hi Jesper,
I'm not running DPDK on the receiving side. Just tcpdump.
Can you please be more specific? What and how to convert to network byte
order?

Thanks
On Apr 9, 2016 7:45 AM, "Jesper Wramberg" <jesper.wramberg@gmail.com> wrote:

> Hey Murad,
>
> Are you running DPDK on the receiving end as well ?
> In any case, I'm guessing you forgot to convert to network byte order ? :-)
>
>
>
> 2016-04-09 12:34 GMT+02:00 Murad Kablan <Murad.Kablan@colorado.edu>:
>
>> Hi,
>> I'm trying to change the IP and port of packets before sending them out.
>> The captured packet in the receiving machines seems to be corrupted as the
>> port is different than the one I inserted. Am I doing the checksum right?
>> And do I need to do other HW configurations?
>>
>> This is my code:
>> struct udp_hdr *udp_h;
>> struct ipv4_hdr *ipv4_h;
>> struct ether_hdr *eth_hdr;
>> eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
>> ipv4_h = (struct ipv4_hdr *)(eth_hdr + 1);
>> udp_h = (struct udp_hdr *)((unsigned char *)ipv4_h + sizeof(struct
>> ipv4_hdr));
>>
>> ipv4_h->dst_addr  = 6777226 //(gateway-ip 10.77.0.51)
>> udp_h->src_port = 88
>> ipv4_h->hdr_checksum = 0;
>> udp_h->dgram_cksum = 0;
>> udp_h->dgram_cksum = rte_ipv4_udptcp_cksum(ipv4_h, udp_h);
>> ipv4_h->hdr_checksum = rte_ipv4_cksum(ipv4_h);
>> l2fwd_simple_forward(m, 0);
>>
>> Thanks,
>>
>> Murad
>>
>
>