我想创建一个DNS响应发送到我的浏览器。我已经创造了一些结构像在RFC:创建DNS响应消息
//DNS header
struct DNS_HEADER
{
unsigned short id;
unsigned char rd :1;
unsigned char tc :1;
unsigned char aa :1;
unsigned char opcode :4;
unsigned char qr :1;
unsigned char rcode :4;
unsigned char cd :1;
unsigned char ad :1;
unsigned char z :1;
unsigned char ra :1;
unsigned short q_count;
unsigned short ans_count;
unsigned short auth_count;
unsigned short add_count;
};
#pragma pack(push, 1)
struct R_DATA
{
unsigned short type;
unsigned short _class;
unsigned int ttl;
unsigned short data_len;
};
#pragma pack(pop)
struct RES_RECORD
{
unsigned char *name;
struct R_DATA *resource;
unsigned char *rdata;
};
现在我试图填补这个结构,所以我可以发送一个有效的DNS响应。我试图发送例如www.google.com与ipaddres 112.12.12.12(只是为了好玩)。
这是我有:
dns = (DNS_HEADER*)malloc(sizeof(DNS_HEADER));
dns->id = (unsigned short) htons(GetCurrentProcessId()); // ID
dns->qr = 1; // We give a response, Volgens RFC: (= query (0), or a response (1).)
dns->opcode = 0; // default
dns->aa = 0; //Not Authoritative,RFC: (= Authoritative Answer - this bit is valid in responses, and specifies that the responding name server is an authority for the domain name in question section.)
dns->tc = 0; // Not truncated
dns->rd = 1; // Enable recursion
dns->ra = 0; // Nameserver supports recursion?
dns->z = 0; // RFC: (= Reserved for future use. Must be zero in all queries and responses.)
dns->rcode = 0; // No error condition
dns->q_count = 0; // No questions!
dns->ad = 0; // How man resource records?
dns->cd = 0; // !checking
dns->ans_count = 1; // We give 1 answer
dns->auth_count = 0; // How many authority entries?
dns->add_count = 0; // How many resource entries?
但你可以看到我对自己在什么来填补一些问题 另外,R_DATA和res_record我无法通过RFC找出什么填写我已经做出的随机回应...
有人可以帮助我吗?