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-rw-r--r--src/dns.cpp98
1 files changed, 46 insertions, 52 deletions
diff --git a/src/dns.cpp b/src/dns.cpp
index 990c2170e..947635571 100644
--- a/src/dns.cpp
+++ b/src/dns.cpp
@@ -44,29 +44,25 @@ extern InspIRCd* ServerInstance;
extern ServerConfig* Config;
#define max(a,b) (a > b ? a : b)
-#define DNS_MAX 8 /* max number of nameservers used */
-#define DNS_CONFIG_FBCK "/etc/resolv.conf" /* fallback config file */
-#define DNS_PORT 53 /* DNS well known port */
-#define DNS_QRY_A 1 /* name to IP address */
-#define DNS_QRY_AAAA 28 /* name to IP6 address */
-#define DNS_QRY_PTR 12 /* IP address to name */
-#define DNS_QRY_MX 15 /* name to MX */
-#define DNS_QRY_TXT 16 /* name to TXT */
-#define DNS_QRY_CNAME 5
+#define min(a,b) (a < b ? a : b)
+
+enum QueryTypes { DNS_QRY_A = 1, DNS_QRY_PTR = 12};
+enum QueryFlags1 { FLAGS1_MASK_RD = 0x01, FLAGS1_MASK_TC = 0x02, FLAGS1_MASK_AA = 0x04, FLAGS1_MASK_OPCODE = 0x78, FLAGS1_MASK_QR = 0x80 };
+enum QueryFlags2 { FLAGS2_MASK_RCODE = 0x0F, FLAGS2_MASK_Z = 0x70, FLAGS2_MASK_RA = 0x80 };
#define DNS_ALIGN (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long))
-#define DNS_TRIES 3
#define RESULTSIZE 1024
-#define min(a,b) (a < b ? a : b)
-static struct in_addr servers4[DNS_MAX]; /* up to DNS_MAX nameservers; populated by dns_init() */
+static struct in_addr servers4[8]; /* up to 8 nameservers; populated by dns_init() */
static int i4; /* actual count of nameservers; set by dns_init() */
static int initdone = 0; /* to ensure dns_init() only runs once (on the first call) */
static int wantclose = 0;
static int lastcreate = -1;
-struct s_connection { /* open DNS query */
+class s_connection
+{
+ public:
struct s_connection *next; /* next in list */
unsigned char id[2];
unsigned int _class;
@@ -75,29 +71,23 @@ struct s_connection { /* open DNS query */
int fd; /* file descriptor returned from sockets */
};
-struct s_rr_middle {
+class s_rr_middle
+{
+ public:
unsigned int type;
unsigned int _class;
unsigned long ttl;
unsigned int rdlength;
};
-#define DNS_POINTER_VALUE 0xc000
-
static s_connection *connection_head = NULL; /* linked list of open DNS queries; populated by dns_add_query(), decimated by dns_getresult_s() */
-struct s_header { /* DNS query header */
+class s_header
+{
+ public:
unsigned char id[2];
unsigned int flags1;
-#define FLAGS1_MASK_QR 0x80
-#define FLAGS1_MASK_OPCODE 0x78 /* bitshift right 3 */
-#define FLAGS1_MASK_AA 0x04
-#define FLAGS1_MASK_TC 0x02
-#define FLAGS1_MASK_RD 0x01
unsigned int flags2;
-#define FLAGS2_MASK_RA 0x80
-#define FLAGS2_MASK_Z 0x70
-#define FLAGS2_MASK_RCODE 0x0f
unsigned int qdcount;
unsigned int ancount;
unsigned int nscount;
@@ -117,40 +107,44 @@ void *dns_align(void *inp) {
}
/*
- * These little hacks are here to avoid alignment and type sizing issues completely by doing manual copies
+ * Optimized by brain, these were using integer division and modulus.
+ * We can use logic shifts and logic AND to replace these even divisions
+ * and multiplications, it should be a bit faster (probably not noticably,
+ * but of course, more impressive). Also made these inline.
*/
-void dns_fill_rr(s_rr_middle* rr, const unsigned char *input) {
- rr->type = input[0] * 256 + input[1];
- rr->_class = input[2] * 256 + input[3];
- rr->ttl = input[4] * 16777216 + input[5] * 65536 + input[6] * 256 + input[7];
- rr->rdlength = input[8] * 256 + input[9];
+
+inline void dns_fill_rr(s_rr_middle* rr, const unsigned char *input) {
+ rr->type = (input[0] << 8) + input[1];
+ rr->_class = (input[2] << 8) + input[3];
+ rr->ttl = (input[4] << 24) + (input[5] << 16) + (input[6] << 8) + input[7];
+ rr->rdlength = (input[8] << 8) + input[9];
}
-void dns_fill_header(s_header *header, const unsigned char *input, const int l) {
+inline void dns_fill_header(s_header *header, const unsigned char *input, const int l) {
header->id[0] = input[0];
header->id[1] = input[1];
header->flags1 = input[2];
header->flags2 = input[3];
- header->qdcount = input[4] * 256 + input[5];
- header->ancount = input[6] * 256 + input[7];
- header->nscount = input[8] * 256 + input[9];
- header->arcount = input[10] * 256 + input[11];
+ header->qdcount = (input[4] << 8) + input[5];
+ header->ancount = (input[6] << 8) + input[7];
+ header->nscount = (input[8] << 8) + input[9];
+ header->arcount = (input[10] << 8) + input[11];
memcpy(header->payload,&input[12],l);
}
-void dns_empty_header(unsigned char *output, const s_header *header, const int l) {
+inline void dns_empty_header(unsigned char *output, const s_header *header, const int l) {
output[0] = header->id[0];
output[1] = header->id[1];
output[2] = header->flags1;
output[3] = header->flags2;
- output[4] = header->qdcount / 256;
- output[5] = header->qdcount % 256;
- output[6] = header->ancount / 256;
- output[7] = header->ancount % 256;
- output[8] = header->nscount / 256;
- output[9] = header->nscount % 256;
- output[10] = header->arcount / 256;
- output[11] = header->arcount % 256;
+ output[4] = header->qdcount >> 8;
+ output[5] = header->qdcount & 0xFF;
+ output[6] = header->ancount >> 8;
+ output[7] = header->ancount & 0xFF;
+ output[8] = header->nscount >> 8;
+ output[9] = header->nscount & 0xFF;
+ output[10] = header->arcount >> 8;
+ output[11] = header->arcount & 0xFF;
memcpy(&output[12],header->payload,l);
}
@@ -168,7 +162,7 @@ void dns_close(int fd) { /* close query */
return;
}
-void DNS::dns_init() { /* on first call only: populates servers4 struct with up to DNS_MAX nameserver IP addresses from /etc/resolv.conf */
+void DNS::dns_init() {
FILE *f;
int i;
in_addr addr4;
@@ -179,8 +173,8 @@ void DNS::dns_init() { /* on first call only: populates servers4 struct with up
initdone = 1;
srand((unsigned int) TIME);
- memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
- f = fopen(DNS_CONFIG_FBCK,"r");
+ memset(servers4,'\0',sizeof(in_addr) * 8);
+ f = fopen("/etc/resolv.conf","r");
if (f == NULL)
return;
while (fgets(buf,1024,f) != NULL) {
@@ -188,7 +182,7 @@ void DNS::dns_init() { /* on first call only: populates servers4 struct with up
i = 10;
while (buf[i] == ' ' || buf[i] == '\t')
i++;
- if (i4 < DNS_MAX) {
+ if (i4 < 8) {
if (dns_aton4_s(&buf[i],&addr4) != NULL)
memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
}
@@ -202,7 +196,7 @@ void DNS::dns_init_2(const char* dnsserver)
in_addr addr4;
i4 = 0;
srand((unsigned int) TIME);
- memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
+ memset(servers4,'\0',sizeof(in_addr) * 8);
if (dns_aton4_s(dnsserver,&addr4) != NULL)
memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
}
@@ -223,7 +217,7 @@ static int dns_send_requests(const s_header *h, const s_connection *s, const int
memset(&addr4,0,sizeof(addr4));
memcpy(&addr4.sin_addr,&servers4[i],sizeof(addr4.sin_addr));
addr4.sin_family = AF_INET;
- addr4.sin_port = htons(DNS_PORT);
+ addr4.sin_port = htons(53);
if (sendto(s->fd, payload, l + 12, 0, (sockaddr *) &addr4, sizeof(addr4)) == -1)
{
return -1;
@@ -559,7 +553,7 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS
while (q == 0 && i < l && o + 256 < 1023) {
if (h.payload[i] > 63) { /* pointer */
memcpy(&p,&h.payload[i],2);
- i = ntohs(p) - DNS_POINTER_VALUE - 12;
+ i = ntohs(p) - 0xC000 - 12;
} else { /* label */
if (h.payload[i] == 0)
q = 1;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 14:27:48 +0000