From d15d0cd2e8af33a39f7e502e9659a1b41815dd6f Mon Sep 17 00:00:00 2001 From: brain Date: Sat, 31 Dec 2005 15:33:09 +0000 Subject: Improving niceness of DNS code, i WILL make this readable! Changed a ton of ugly firedns #define's to enums git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@2715 e03df62e-2008-0410-955e-edbf42e46eb7 --- src/dns.cpp | 98 +++++++++++++++++++++++++++++-------------------------------- 1 file 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; -- cgit v1.2.3