Hashing two integer to one key

gistfile1.c

static int _HashingSourceInfo(in_addr_t sourceIp, uint32_t sourceId)
{
    // [0] Cantor pairing function
    unsigned long long key = (sourceIp + sourceId) * (sourceIp + sourceId + 1) / 2 + sourceId;

    // Ref: http://elliottback.com/wp/hashmap-implementation-in-c/
    // [1] Robert Jenkins 32 bit Mix Function
    key += (key << 12);
    key ^= (key >> 22);
    key += (key << 4);
    key ^= (key >> 9);
    key += (key << 10);
    key ^= (key >> 2);
    key += (key << 7);
    key ^= (key >> 12);

    // [2] Knuth's Multiplicative Hash
    key = (key >> 3) * 2654435761UL;

    return key % NF_V9_MAX_SOURCE_ENTRIES;
}