예제 #1
0
bool build_handshake_packet(nabto_connect* con, uint8_t* buffer, size_t bufferLength, size_t* packetLength) {
    uint8_t* packetPtr;
    
    /*
     * type,   1 bytes
     * flags,  1 bytes
     * nsi cp, 4 bytes
     * nsi sp, 4 bytes
     * nsi co, 4 bytes
     * id, 20 bytes
     */
    size_t nonceLength = 38;
    uint8_t nonce[38];
    uint8_t* noncePtr = nonce;
    
    packetPtr = insert_header(buffer, con->cpnsi, con->spnsi, NP_PACKET_HDR_TYPE_GW_CONN_U, false, 0, 0, con->consi);

    //NOTE: These type and flags must match the connection attributes set
    //in the unabto_tcp_fallback_connect_thread when a connection is
    //established.
    WRITE_U8(noncePtr, NP_GW_CONN_U_TYPE_TCP); noncePtr+=1;
    WRITE_U8(noncePtr, NP_GW_CONN_U_FLAG_RELIABLE); noncePtr+=1;
    WRITE_U32(noncePtr, con->cpnsi); noncePtr+=4;
    WRITE_U32(noncePtr, con->spnsi); noncePtr+=4;
    memcpy(noncePtr, con->consi, 8); noncePtr+=8;
    memcpy(noncePtr, con->gatewayId, 20);

    packetPtr = insert_payload(packetPtr, NP_PAYLOAD_TYPE_NONCE, nonce, nonceLength);
    
    *packetLength = packetPtr - buffer;

    insert_length(buffer, *packetLength);
    return true;
}
예제 #2
0
/* Reconstruct nabto header with crypto payload header. */
uint8_t* reconstruct_header(uint8_t* buf, const nabto_packet_header * hdr)
{
    uint8_t* ptr;

    // insert copy of request header (Length will be inserted later)

    ptr = buf;

    /* Write fixed part of packet header */
    WRITE_U32(ptr, hdr->nsi_cp);      ptr += 4;
    WRITE_U32(ptr, hdr->nsi_sp);      ptr += 4;
    WRITE_U8(ptr,  hdr->type);        ptr += 1;
    WRITE_U8(ptr,  hdr->version);     ptr += 1;
    WRITE_U8(ptr,  hdr->rsvd);        ptr += 1;
    WRITE_U8(ptr,  hdr->flags | NP_PACKET_HDR_FLAG_RESPONSE); ptr += 1;
    WRITE_U16(ptr, hdr->seq);         ptr += 2;
    /*WRITE_U16(ptr, len);*/          ptr += 2; /* Length to be packed later */

    /* Write NSI.co to packet header (optional) */
    if (hdr->flags & NP_PACKET_HDR_FLAG_NSI_CO) {
        memcpy(ptr, (const void*) hdr->nsi_co, 8);  ptr += 8;
    }

    /* Write tag to packet header (optional) */
    if (hdr->flags & NP_PACKET_HDR_FLAG_TAG) {
        WRITE_U16(ptr, hdr->tag);     ptr += 2;
    }

    {
        ptrdiff_t diff = ptr - buf;
        if (hdr->hlen != (uint16_t)(diff)) {
            NABTO_LOG_ERROR(("header length mismatch: %" PRIu16 " != %" PRIptrdiff " !!!!!!!!!!!!!!!!!!!", hdr->hlen, diff));
            return NULL;
        }
    }

    // insert crypto header (len and code will be inserted later)
    WRITE_U8(ptr, NP_PAYLOAD_TYPE_CRYPTO);                    ptr += 1;
    WRITE_U8(ptr, NP_PAYLOAD_HDR_FLAG_NONE);                /*ptr += 1;
    WRITE_U16(ptr, len);                                      ptr += 2;
    WRITE_U16(ptr, code);                                     ptr += 2;*/
    /* len and code is patched by unabto_encrypt() */         ptr += 5;

    return ptr; /* return end of packet (so far) */
}