Thank your answers, that helped me out.
------------------ ???????? ------------------ ??????: "Shyam Shrivastav"<[email protected]>; ????????: 2018??12??6??(??????) ????2:22 ??????: "bai bakari"<[email protected]>; ????: "dev"<[email protected]>; ????: Re: [dpdk-dev] About the data payload of rte_mbuf? And if just payload length is required one can get by subtracting (ip-hdr-len + tcp-offset) from total length in ip header ... On Thu, Dec 6, 2018 at 11:18 AM Shyam Shrivastav <[email protected]> wrote: As per my understanding payload = (uint8_t *)tcp_hdr + (tcp_hdr->data_off << 2); should be payload = (uint8_t *)tcp_hdr + (tcp_hdr->data_off >> 4) << 2); Note that data offset is 4 most significant bits of the byte, refer tcp header On Thu, Dec 6, 2018 at 9:15 AM bai bakari <[email protected]> wrote: Hi, Now, I want to get the data payload of rte_mbuf, and i wrote the following code: struct ipv4_hdr *ipv4_hdr; struct tcp_hdr *tcp_hdr; uint32_t payload_len, ip_len; uint8_t *payload = NULL; ipv4_hdr = rte_pktmbuf_mtod_offset(m, struct ipv4_hdr *, sizeof(struct ether_hdr)); ip_len = ntohs(ipv4_hdr->total_length); if (ipv4_hdr->next_proto_id == IPPROTO_TCP) { tcp_hdr = (struct tcp_hdr *)((uint8_t *)ipv4_hdr + ((ipv4_hdr->version_ihl & 0xf) << 2)); payload = (uint8_t *)tcp_hdr + (tcp_hdr->data_off << 2); payload_len = ip_len - (payload - (uint8_t *)ipv4_hdr); } when i send packets using dpdk-pktgen, i found: ip_len = 46 ip_header_len = 20 but the tcp_header_len=(tcp_hdr->data_off << 2)=0, and (payload - (uint8_t *)ipv4_hdr) = 340 > ip_len. I'm confused, is there any errors about the code to compute the payload_len of rte_mbuf? I think maybe the dpdk-pktgen cannot send the packets with payload? I'm a beginner, anyone can help me how to compute the payload_len of rte_mbuf and test it? Thank you in advance!
