From: "Jain, Neeraj 3. (NSN - IN/Bangalore)" <neeraj.3.jain@nsn.com>
To: "dev@dpdk.org" <dev@dpdk.org>
Subject: [dpdk-dev] Question regarding multi-segment packet forwarding
Date: Tue, 25 Mar 2014 12:28:37 +0000 [thread overview]
Message-ID: <2AA69572D8087D4FA7345FB70631D59A1FD79E20@SGSIMBX007.nsn-intra.net> (raw)
Hi,
I have a question regarding sending of multi-segment packets. I have modified the l2fwd sample application to send a multi-segment packet on tx queue whenever the application receives any packet on Rx queue. Pseudo-code is as below
Function l2fwd_simple_forward(.....)
{
Allocate new mbuf with "rte_pktmbuf_alloc"
Copy Ethernet, IP and UDP Headers into this new mbuf
Remove the Ethernet, ip and udp header from the beginning of received mbuf by calling rte_pktmbuf_adj api
Join the received buffer with new mbuf as follows:
{
new_mbuf->pkt.next = mbuf
/* accumulate number of segments and total length. */
new_mbuf ->pkt.nb_segs = new_mbuf->pkt.nb_segs + mbuf->pkt.nb_segs;
new_mbuf ->pkt.pkt_len += mbuf->pkt.pkt_len;
/* reset pkt_len and nb_segs for chained fragment. */
mbuf->pkt.pkt_len = mbuf->pkt.data_len;
mbuf->pkt.nb_segs = 1;
}
}
When I call rte_pktmbuf_dump on the new_mbuf, it shows both the segments. Also l2fwd_send_packet (which eventually calls rte_eth_tx_burst) returns 1 indicating that packet was sent successfully. But I do not receive any packet on the other end.
However, instead of multi-segment packet, if I try sending only the new_mbuf that was created, then the packet is sent successfully.
So, Can you please advice if I am correct in the way multi-segment packets are created or if I am missing something here. Thanks
~Neeraj
reply other threads:[~2014-03-25 12:27 UTC|newest]
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