HTTP-DNS extends报文

1、明确header中Additional（附加区域的数量），设置未0x0001

2、设置Additional（附加信息）

2.1、报文格式

       +------------+--------------+------------------------------+
       | Field Name | Field Type   | Description                  |
       +------------+--------------+------------------------------+
       | NAME       | domain name  | MUST be 0 (root domain)      |
       | TYPE       | u_int16_t    | OPT (41)                     |
       | CLASS      | u_int16_t    | requestor's UDP payload size |
       | TTL        | u_int32_t    | extended RCODE and flags     |
       | RDLEN      | u_int16_t    | length of all RDATA          |
       | RDATA      | octet stream | {attribute,value} pairs      |
       +------------+--------------+------------------------------+

RFC文档

NAME：0x00
TYPE：0x0029(41)
CLASS：0x1000?
TTL-EXTENDED-RCODE：0x00
TTL-VERSION：0x00
TTL-Z：0x0000
RDLEN：0x000c
RDATA-OPTION-CODE ：0x0008
RDATA-OPTION-LENGTH：0x0008
RDATA(FAMILY)：0x0001
RDATA（SOURCE PREFIX-LENGTH ）：0x20
RDATA（SCOPE PREFIX-LENGTH）：0x00
RDATA(ADDRESS )：0x70707070

说明

TYPE：0x0029即41，RFC文档,其中
| OPT | 41 | OPT | [RFC3225][RFC6891] |

2.2、TTL格式

                  +0 (MSB)                            +1 (LSB)
       +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    0: |         EXTENDED-RCODE        |            VERSION            |
       +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    2: | DO|                           Z                               |
       +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

2.3、RDATA格式

RFC文档

                  +0 (MSB)                            +1 (LSB)
       +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    0: |                          OPTION-CODE                          |
       +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    2: |                         OPTION-LENGTH                         |
       +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    4: |                                                               |
       /                          OPTION-DATA                          /
       /                                                               /
       +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

2.4、OPTION-DATA 格式

RFC文档


                +0 (MSB)                            +1 (LSB)
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   0: |                          OPTION-CODE                          |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   2: |                         OPTION-LENGTH                         |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   4: |                            FAMILY                             |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   6: |     SOURCE PREFIX-LENGTH      |     SCOPE PREFIX-LENGTH       |
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   8: |                           ADDRESS...                          /
      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+