30.09 2

#include <stdio.h>
#include <stdint.h>

typedef union {
    uint32_t data;

    struct {
        uint32_t version: 4;
        uint32_t ihl: 4;

        uint32_t dscp: 6;
        uint32_t ecn: 2;

        uint32_t total_len: 16;
    } un;
} ip_v4;

ip_v4 new_ipv4(const uint32_t ipv4_number) {
    ip_v4 ip;
    ip.data = ipv4_number;
    return ip;
}

int main() {
    const ip_v4 ip = new_ipv4(32);
    printf("version: %u, ihl: %u, dscp: %u, ecn: %u, total len: %u, size: %lu", ip.un.version, ip.un.ihl, ip.un.dscp, ip.un.ecn, ip.un.total_len, sizeof(ip_v4));
    return 0;
}

/* 1 Union Solution
 #include <stdio.h>
#include <stdint.h>

typedef union {
    uint32_t version: 4;
    uint32_t ihl: 4;

    uint32_t dscp: 6;
    uint32_t ecn: 2;

    uint32_t total_len: 16;
} ip_v4;

ip_v4 new_ipv4(const uint32_t ipv4_number) {
    ip_v4 ip;

    ip.version = ipv4_number >> (16 + 2 + 6 + 4);
    ip.ihl = (ipv4_number << 4) >> (6 + 2 + 16);
    ip.dscp = (ipv4_number << (4 + 4)) >> (2 + 16);
    ip.ecn = (ipv4_number << (4 + 4 + 6)) >> (16);
    ip.total_len = ipv4_number << (4 + 4 + 6 + 2);

    return ip;
}

int main() {
    const ip_v4 ip = new_ipv4(32);
    printf("version: %u, ihl: %u, dscp: %u, ecn: %u, total len: %u, size: %lu", ip.version, ip.ihl, ip.dscp, ip.ecn, ip.total_len, sizeof(ip_v4));
    return 0;
}

 */