[dpdk-dev] bytes order of ip header in dpdk 2.1

[Moon-Sang Lee <sang0627@gmail.com>]

Once receiving a packet by rte_eth_rx_burst(), I printed IP header as
below.
It seems that length(uint16_t) is in big endian, but ip addresses are in
little endian.
I'm confused and appreciate any comment.

### print_ipv4_header src = 11.0.168.192, dst = 2.173.248.143, length = 60,
ttl = 64, proto = 6

This log was printed with these functions.

void print_ipv4_header(struct rte_mbuf *m) {
    struct ether_hdr *eth_header;
    struct ipv4_hdr *ipv4_header;
    uint16_t length;
    uint8_t ttl, proto;
    uint32_t src_ip, dst_ip;
    char src_ip_str[MAX_IP_STR_LEN], dst_ip_str[MAX_IP_STR_LEN];

    eth_header = rte_pktmbuf_mtod(m, struct ether_hdr *);
    ipv4_header = (struct ipv4_hdr*)(eth_header + 1);
*    length = rte_be_to_cpu_16(ipv4_header->total_length);*
    ttl = ipv4_header->time_to_live;
    proto = ipv4_header->next_proto_id;
*    src_ip = rte_be_to_cpu_32(ipv4_header->src_addr);*
*    dst_ip = rte_be_to_cpu_32(ipv4_header->dst_addr);*
    convert_ip_to_string(src_ip_str, src_ip);
    convert_ip_to_string(dst_ip_str, dst_ip);

    debug("### print_ipv4_header src = %s, dst = %s, length = %d, ttl = %d,
proto = %d", src_ip_str, dst_ip_str, length, ttl, proto);
}

void convert_ip_to_string(char *str, uint32_t ip) {
    unsigned char *ptr = (unsigned char *)&ip;

    sprintf(str, "%u.%u.%u.%u", ptr[0], ptr[1], ptr[2], ptr[3]);
}



-- 
Moon-Sang Lee, SW Engineer
Email: sang0627@gmail.com
Wisdom begins in wonder. *Socrates*