Method parseNlriData_v4

Server/src/bgp/UpdateMsg.cpp:173–236

* Parses NLRI info (IPv4) from the BGP message * * \details * Will get the NLRI and Withdrawn prefix entries from the data buffer. As per RFC, * this is only for v4. V6/mpls is via mpbgp attributes (RFC4760) * * \param [in] data Pointer to the start of the prefixes to be parsed * \param [in] len Length of the data in bytes to be read * \param [out] prefixes

 * \param [out]  prefixes   Reference to a list<prefix_tuple> to be updated with entries
 */
void UpdateMsg::parseNlriData_v4(u_char *data, uint16_t len, std::list<bgp::prefix_tuple> &prefixes) {
    u_char       ipv4_raw[4];
    char         ipv4_char[16];
    u_char       addr_bytes;

    bgp::prefix_tuple tuple;

    if (len <= 0 or data == NULL)
        return;

    // TODO: Can extend this to support multicast, but right now we set it to unicast v4
    // Set the type for all to be unicast V4
    tuple.type = bgp::PREFIX_UNICAST_V4;
    tuple.isIPv4 = true;

    // Loop through all prefixes
    for (size_t read_size=0; read_size < len; read_size++) {

        bzero(ipv4_raw, sizeof(ipv4_raw));
        bzero(tuple.prefix_bin, sizeof(tuple.prefix_bin));

        // Parse add-paths if enabled
        if (peer_info->add_path_capability.isAddPathEnabled(bgp::BGP_AFI_IPV4, bgp::BGP_SAFI_UNICAST)
                and (len - read_size) >= 4) {
            memcpy(&tuple.path_id, data, 4);
            bgp::SWAP_BYTES(&tuple.path_id);
            data += 4; read_size += 4;
        } else
            tuple.path_id = 0;

        // set the address in bits length
        tuple.len = *data++;

        // Figure out how many bytes the bits requires
        addr_bytes = tuple.len / 8;
        if (tuple.len % 8)
            ++addr_bytes;

        SELF_DEBUG("%s: rtr=%s: Reading NLRI data prefix bits=%d bytes=%d", peer_addr.c_str(),
                    router_addr.c_str(), tuple.len, addr_bytes);

        if (addr_bytes <= 4) {
            memcpy(ipv4_raw, data, addr_bytes);
            read_size += addr_bytes;
            data += addr_bytes;

            // Convert the IP to string printed format
            inet_ntop(AF_INET, ipv4_raw, ipv4_char, sizeof(ipv4_char));
            tuple.prefix.assign(ipv4_char);
            SELF_DEBUG("%s: rtr=%s: Adding prefix %s len %d", peer_addr.c_str(),
                        router_addr.c_str(), ipv4_char, tuple.len);

            // set the raw/binary address
            memcpy(tuple.prefix_bin, ipv4_raw, sizeof(ipv4_raw));

            // Add tuple to prefix list
            prefixes.push_back(tuple);