src/mod/dns.mod/coredns.c File Reference

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <errno.h>

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Data Structures
struct	packetheader
Defines
#define	BASH_SIZE   8192
#define	HOSTNAMELEN   255
#define	RES_ERR   "DNS Resolver error: "
#define	RES_MSG   "DNS Resolver: "
#define	RES_WRN   "DNS Resolver warning: "
#define	MAX_PACKETSIZE   (PACKETSZ)
#define	MAX_DOMAINLEN   (MAXDNAME)
#define	nonull(s)   (s) ? s : nullstring
#define	BASH_MODULO(x)   ((x) & 8191)
#define	HFIXEDSZ   (sizeof(packetheader))
#define	getheader_rd(x)   (x->databyte_a & 1)
#define	getheader_tc(x)   ((x->databyte_a >> 1) & 1)
#define	getheader_aa(x)   ((x->databyte_a >> 2) & 1)
#define	getheader_opcode(x)   ((x->databyte_a >> 3) & 15)
#define	getheader_qr(x)   (x->databyte_a >> 7)
#define	getheader_rcode(x)   (x->databyte_b & 15)
#define	getheader_pr(x)   ((x->databyte_b >> 6) & 1)
#define	getheader_ra(x)   (x->databyte_b >> 7)
#define	sucknetword(x)   ((x)+=2,((u_16bit_t) (((x)[-2] << 8) | ((x)[-1] << 0))))
#define	sucknetshort(x)   ((x)+=2,((short) (((x)[-2] << 8) | ((x)[-1] << 0))))
#define	sucknetdword(x)
#define	sucknetlong(x)
Functions
static struct resolve *	allocresolve ()
static u_32bit_t	getidbash (u_16bit_t id)
static u_32bit_t	getipbash (IP ip)
static u_32bit_t	gethostbash (char *host)
static void	linkresolveid (struct resolve *addrp)
static void	unlinkresolveid (struct resolve *rp)
static void	linkresolvehost (struct resolve *addrp)
static void	unlinkresolvehost (struct resolve *rp)
static void	linkresolveip (struct resolve *addrp)
static void	unlinkresolveip (struct resolve *rp)
static void	linkresolve (struct resolve *rp)
static void	untieresolve (struct resolve *rp)
static void	unlinkresolve (struct resolve *rp)
static struct resolve *	findid (u_16bit_t id)
static struct resolve *	findhost (char *hostn)
static struct resolve *	findip (IP ip)
static void	dorequest (char *s, int type, u_16bit_t id)
static void	resendrequest (struct resolve *rp, int type)
static void	sendrequest (struct resolve *rp, int type)
static void	failrp (struct resolve *rp, int type)
static void	passrp (struct resolve *rp, long ttl, int type)
static void	parserespacket (u_8bit_t *s, int l)
static void	dns_ack (void)
static void	dns_check_expires (void)
static void	dns_lookup (IP ip)
static void	dns_forward (char *hostn)
static int	init_dns_network (void)
static int	init_dns_core (void)
Variables
static u_32bit_t	resrecvbuf [((PACKETSZ)+7) >> 2]
static struct resolve *	idbash [8192]
static struct resolve *	ipbash [8192]
static struct resolve *	hostbash [8192]
static struct resolve *	expireresolves = 0
static IP	localhost
static long	idseed = 0xdeadbeef
static long	aseed
static int	resfd
static char	tempstring [512]
static char	namestring [1024+1]
static char	stackstring [1024+1]
static const char	nullstring [] = ""

---

Define Documentation

#define BASH_MODULO

(

x

)

((x) & 8191)

Definition at line 61 of file coredns.c.

Referenced by gethostbash(), getidbash(), and getipbash().

#define BASH_SIZE   8192

Definition at line 48 of file coredns.c.

Referenced by init_dns_core().

#define getheader_aa

(

x

)

((x->databyte_a >> 2) & 1)

Definition at line 144 of file coredns.c.

#define getheader_opcode

(

x

)

((x->databyte_a >> 3) & 15)

Definition at line 145 of file coredns.c.

Referenced by parserespacket().

#define getheader_pr

(

x

)

((x->databyte_b >> 6) & 1)

Definition at line 148 of file coredns.c.

#define getheader_qr

(

x

)

(x->databyte_a >> 7)

Definition at line 146 of file coredns.c.

Referenced by parserespacket().

#define getheader_ra

(

x

)

(x->databyte_b >> 7)

Definition at line 149 of file coredns.c.

#define getheader_rcode

(

x

)

(x->databyte_b & 15)

Definition at line 147 of file coredns.c.

Referenced by parserespacket().

#define getheader_rd

(

x

)

(x->databyte_a & 1)

Definition at line 142 of file coredns.c.

#define getheader_tc

(

x

)

((x->databyte_a >> 1) & 1)

Definition at line 143 of file coredns.c.

Referenced by parserespacket().

#define HFIXEDSZ   (sizeof(packetheader))

Definition at line 136 of file coredns.c.

Referenced by parserespacket().

#define HOSTNAMELEN   255

Definition at line 49 of file coredns.c.

Referenced by parserespacket().

#define MAX_DOMAINLEN   (MAXDNAME)

Definition at line 56 of file coredns.c.

#define MAX_PACKETSIZE   (PACKETSZ)

Definition at line 55 of file coredns.c.

Referenced by dns_ack(), and dorequest().

#define nonull

(

s

)

(s) ? s : nullstring

Definition at line 60 of file coredns.c.

Referenced by dns_check_expires(), and dns_event_failure().

#define RES_ERR   "DNS Resolver error: "

Definition at line 51 of file coredns.c.

Referenced by dns_ack(), dorequest(), and parserespacket().

#define RES_MSG   "DNS Resolver: "

Definition at line 52 of file coredns.c.

Referenced by dns_ack(), dns_check_expires(), dns_forward(), dns_lookup(), failrp(), parserespacket(), passrp(), and resendrequest().

#define RES_WRN   "DNS Resolver warning: "

Definition at line 53 of file coredns.c.

Referenced by dns_check_expires(), and parserespacket().

#define sucknetdword

(

x

)

Value:

((x)+=4,((dword) (((x)[-4] << 24) | ((x)[-3] << 16) | \
                                          ((x)[-2] <<  8) | ((x)[-1] <<  0))))

Definition at line 153 of file coredns.c.

#define sucknetlong

(

x

)

Value:

((x)+=4,((long)  (((x)[-4] << 24) | ((x)[-3] << 16) | \
                                          ((x)[-2] <<  8) | ((x)[-1] <<  0))))

Definition at line 155 of file coredns.c.

Referenced by parserespacket().

#define sucknetshort

(

x

)

((x)+=2,((short) (((x)[-2] << 8) | ((x)[-1] << 0))))

Definition at line 152 of file coredns.c.

#define sucknetword

(

x

)

((x)+=2,((u_16bit_t) (((x)[-2] << 8) | ((x)[-1] << 0))))

Definition at line 151 of file coredns.c.

Referenced by parserespacket().

---

Function Documentation

static struct resolve* allocresolve

(

)

[static, read]

Definition at line 222 of file coredns.c.

References egg_bzero, and nmalloc.

Referenced by dns_forward(), and dns_lookup().

{
  struct resolve *rp;

  rp = nmalloc(sizeof *rp);
  egg_bzero(rp, sizeof(struct resolve));
  return rp;
}

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static void dns_ack

(

void

)

[static]

Definition at line 925 of file coredns.c.

References ddebug1, iptostr, localhost, MAX_PACKETSIZE, parserespacket(), RES_ERR, RES_MSG, resfd, and resrecvbuf.

Referenced by dns_socket().

{
  struct sockaddr_in from;
  unsigned int fromlen = sizeof(struct sockaddr_in);
  int r, i;

  r = recvfrom(resfd, (u_8bit_t *) resrecvbuf, MAX_PACKETSIZE, 0,
               (struct sockaddr *) &from, &fromlen);
  if (r <= 0) {
    ddebug1(RES_MSG "Socket error: %s", strerror(errno));
    return;
  }
  /* Check to see if this server is actually one we sent to */
  if (from.sin_addr.s_addr == localhost) {
    for (i = 0; i < _res.nscount; i++)
      /* 0.0.0.0 replies as 127.0.0.1 */
      if ((_res.nsaddr_list[i].sin_addr.s_addr == from.sin_addr.s_addr) ||
          (!_res.nsaddr_list[i].sin_addr.s_addr))
        break;
  } else {
    for (i = 0; i < _res.nscount; i++)
      if (_res.nsaddr_list[i].sin_addr.s_addr == from.sin_addr.s_addr)
        break;
  }
  if (i == _res.nscount) {
    ddebug1(RES_ERR "Received reply from unknown source: %s",
            iptostr(from.sin_addr.s_addr));
  } else
    parserespacket((u_8bit_t *) resrecvbuf, r);
}

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static void dns_check_expires

(

void

)

[static]

Definition at line 958 of file coredns.c.

References ddebug0, ddebug1, ddebug4, dns_maxsends, resolve::expiretime, failrp(), resolve::hostn, resolve::ip, iptostr, resolve::next, nonull, now, RES_MSG, RES_WRN, resendrequest(), resolve::sends, resolve::state, STATE_AREQ, STATE_FAILED, STATE_FINISHED, STATE_PTRREQ, unlinkresolve(), and untieresolve().

Referenced by dns_close(), and dns_start().

{
  struct resolve *rp, *nextrp;

  /* Walk through sorted list ... */
  for (rp = expireresolves; (rp) && (now >= rp->expiretime); rp = nextrp) {
    nextrp = rp->next;
    untieresolve(rp);
    switch (rp->state) {
    case STATE_FINISHED:       /* TTL has expired */
    case STATE_FAILED:         /* Fake TTL has expired */
      ddebug4(RES_MSG
              "Cache record for \"%s\" (%s) has expired. (state: %u)  Marked for expire at: %ld.",
              nonull(rp->hostn), iptostr(rp->ip), rp->state, rp->expiretime);
      unlinkresolve(rp);
      break;
    case STATE_PTRREQ:         /* T_PTR send timed out */
      if (rp->sends <= dns_maxsends) {
        ddebug1(RES_MSG "Resend #%d for \"PTR\" query...", rp->sends - 1);
        resendrequest(rp, T_PTR);
      } else {
        ddebug0(RES_MSG "\"PTR\" query timed out.");
        failrp(rp, T_PTR);
      }
      break;
    case STATE_AREQ:           /* T_A send timed out */
      if (rp->sends <= dns_maxsends) {
        ddebug1(RES_MSG "Resend #%d for \"A\" query...", rp->sends - 1);
        resendrequest(rp, T_A);
      } else {
        ddebug0(RES_MSG "\"A\" query timed out.");
        failrp(rp, T_A);
      }
      break;
    default:                   /* Unknown state, let it expire */
      ddebug1(RES_WRN "Unknown request state %d. Request expired.", rp->state);
      failrp(rp, 0);
    }
  }
}

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static void dns_forward

(

char *

hostn

)

[static]

Definition at line 1031 of file coredns.c.

References allocresolve(), call_ipbyhost, ddebug0, ddebug1, ddebug2, dns_event_failure(), dns_event_success(), egg_inet_aton, findhost(), resolve::hostn, resolve::ip, iptostr, linkresolvehost(), nmalloc, RES_MSG, sendrequest(), resolve::sends, resolve::state, STATE_AREQ, STATE_FAILED, and STATE_FINISHED.

Referenced by dns_close(), and dns_start().

{
  struct resolve *rp;
  struct in_addr inaddr;

  /* Check if someone passed us an IP address as hostname
   * and return it straight away.
   */
  if (egg_inet_aton(hostn, &inaddr)) {
    call_ipbyhost(hostn, ntohl(inaddr.s_addr), 1);
    return;
  }
  if ((rp = findhost(hostn))) {
    if (rp->state == STATE_FINISHED || rp->state == STATE_FAILED) {
      if (rp->state == STATE_FINISHED && rp->ip) {
        ddebug2(RES_MSG "Used cached record: %s == \"%s\".", hostn,
                iptostr(rp->ip));
        dns_event_success(rp, T_A);
      } else {
        ddebug1(RES_MSG "Used failed record: %s == ???", hostn);
        dns_event_failure(rp, T_A);
      }
    }
    return;
  }
  ddebug0(RES_MSG "Creating new record");
  rp = allocresolve();
  rp->state = STATE_AREQ;
  rp->sends = 1;
  rp->hostn = nmalloc(strlen(hostn) + 1);
  strcpy(rp->hostn, hostn);
  linkresolvehost(rp);
  sendrequest(rp, T_A);
}

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static void dns_lookup

(

IP

ip

)

[static]

Definition at line 1001 of file coredns.c.

References allocresolve(), ddebug0, ddebug1, ddebug2, dns_event_failure(), dns_event_success(), findip(), resolve::hostn, resolve::ip, iptostr, linkresolveip(), RES_MSG, sendrequest(), resolve::sends, resolve::state, STATE_FAILED, STATE_FINISHED, and STATE_PTRREQ.

Referenced by dns_close(), and dns_start().

{
  struct resolve *rp;

  ip = htonl(ip);
  if ((rp = findip(ip))) {
    if (rp->state == STATE_FINISHED || rp->state == STATE_FAILED) {
      if (rp->state == STATE_FINISHED && rp->hostn) {
        ddebug2(RES_MSG "Used cached record: %s == \"%s\".",
                iptostr(ip), rp->hostn);
        dns_event_success(rp, T_PTR);
      } else {
        ddebug1(RES_MSG "Used failed record: %s == ???", iptostr(ip));
        dns_event_failure(rp, T_PTR);
      }
    }
    return;
  }

  ddebug0(RES_MSG "Creating new record");
  rp = allocresolve();
  rp->state = STATE_PTRREQ;
  rp->sends = 1;
  rp->ip = ip;
  linkresolveip(rp);
  sendrequest(rp, T_PTR);
}

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static void dorequest	(	char *	s,
		int	type,
		u_16bit_t	id
	)			[static]

Definition at line 561 of file coredns.c.

References ddebug0, packetheader::id, MAX_PACKETSIZE, nfree, nmalloc, NULL, RES_ERR, and resfd.

Referenced by resendrequest().

{
  packetheader *hp;
  int r, i;
  u_8bit_t *buf;

  /* Use malloc here instead of a static buffer, as per res_mkquery()'s manual
   * buf should be aligned on an eight byte boundary. malloc() should return a
   * pointer to an address properly aligned for any data type. Failing to
   * provide a aligned buffer will result in a SIGBUS crash atleast on SPARC
   * CPUs.
   */
  buf = nmalloc(MAX_PACKETSIZE + 1);
  r = res_mkquery(QUERY, s, C_IN, type, NULL, 0, NULL, buf, MAX_PACKETSIZE);
  if (r == -1) {
    ddebug0(RES_ERR "Query too large.");
    return;
  }
  hp = (packetheader *) buf;
  hp->id = id;                  /* htons() deliberately left out (redundant) */
  for (i = 0; i < _res.nscount; i++)
    (void) sendto(resfd, buf, r, 0,
                  (struct sockaddr *) &_res.nsaddr_list[i],
                  sizeof(struct sockaddr));
  nfree(buf);
}

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static void failrp	(	struct resolve *	rp,
		int	type
	)			[static]

Definition at line 629 of file coredns.c.

References ddebug0, dns_event_failure(), dns_negcache, resolve::expiretime, linkresolve(), now, RES_MSG, resolve::state, STATE_FAILED, STATE_FINISHED, and untieresolve().

Referenced by dns_check_expires(), and parserespacket().

{
  if (rp->state == STATE_FINISHED)
    return;
  rp->expiretime = now + dns_negcache;
  rp->state = STATE_FAILED;

  /* Expire time was changed, reinsert entry to maintain order */
  untieresolve(rp);
  linkresolve(rp);

  ddebug0(RES_MSG "Lookup failed.");
  dns_event_failure(rp, type);
}

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static struct resolve* findhost

(

char *

hostn

)

[static, read]

Definition at line 507 of file coredns.c.

References egg_strcasecmp, gethostbash(), resolve::hostn, resolve::nexthost, NULL, and resolve::previoushost.

Referenced by dns_forward().

{
  struct resolve *rp;
  int bashnum;

  bashnum = gethostbash(hostn);
  rp = hostbash[bashnum];
  if (rp) {
    while ((rp->nexthost) &&
          (egg_strcasecmp(hostn, rp->nexthost->hostn) >= 0))
      rp = rp->nexthost;
    while ((rp->previoushost) &&
           (egg_strcasecmp(hostn, rp->previoushost->hostn) <= 0))
      rp = rp->previoushost;
    if (egg_strcasecmp(hostn, rp->hostn))
      return NULL;
    else {
      hostbash[bashnum] = rp;
      return rp;
    }
  }
  return rp;                    /* NULL */
}

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static struct resolve* findid

(

u_16bit_t

id

)

[static, read]

Definition at line 484 of file coredns.c.

References getidbash(), resolve::id, resolve::nextid, NULL, and resolve::previousid.

Referenced by parserespacket(), and sendrequest().

{
  struct resolve *rp;
  int bashnum;

  bashnum = getidbash(id);
  rp = idbash[bashnum];
  if (rp) {
    while ((rp->nextid) && (id >= rp->nextid->id))
      rp = rp->nextid;
    while ((rp->previousid) && (id <= rp->previousid->id))
      rp = rp->previousid;
    if (id == rp->id) {
      idbash[bashnum] = rp;
      return rp;
    } else
      return NULL;
  }
  return rp;                    /* NULL */
}

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static struct resolve* findip

(

IP

ip

)

[static, read]

Definition at line 533 of file coredns.c.

References getipbash(), resolve::ip, resolve::nextip, NULL, and resolve::previousip.

Referenced by dns_lookup().

{
  struct resolve *rp;
  u_32bit_t bashnum;

  bashnum = getipbash(ip);
  rp = ipbash[bashnum];
  if (rp) {
    while ((rp->nextip) && (ip >= rp->nextip->ip))
      rp = rp->nextip;
    while ((rp->previousip) && (ip <= rp->previousip->ip))
      rp = rp->previousip;
    if (ip == rp->ip) {
      ipbash[bashnum] = rp;
      return rp;
    } else
      return NULL;
  }
  return rp;                    /* NULL */
}

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static u_32bit_t gethostbash

(

char *

host

)

[static]

Definition at line 252 of file coredns.c.

References BASH_MODULO.

Referenced by findhost(), linkresolvehost(), and unlinkresolvehost().

{
  u_32bit_t bashvalue = 0;

  for (; *host; host++) {
    bashvalue ^= *host;
    bashvalue += (*host >> 1) + (bashvalue >> 1);
  }
  return BASH_MODULO(bashvalue);
}

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static u_32bit_t getidbash

(

u_16bit_t

id

)

[inline, static]

Definition at line 238 of file coredns.c.

References BASH_MODULO.

Referenced by findid(), linkresolveid(), and unlinkresolveid().

{
  return (u_32bit_t) BASH_MODULO(id);
}

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static u_32bit_t getipbash

(

IP

ip

)

[inline, static]

Definition at line 245 of file coredns.c.

References BASH_MODULO.

Referenced by findip(), linkresolveip(), and unlinkresolveip().

{
  return (u_32bit_t) BASH_MODULO(ip);
}

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static int init_dns_core

(

void

)

[static]

Definition at line 1103 of file coredns.c.

References aseed, BASH_SIZE, init_dns_network(), LOG_MISC, NULL, and putlog.

Referenced by dns_start().

{
  int i;

  /* Initialise the resolv library. */
  res_init();
  if (!_res.nscount)
    putlog(LOG_MISC, "*", "No nameservers found.");
  _res.options |= RES_RECURSE | RES_DEFNAMES | RES_DNSRCH;
  for (i = 0; i < _res.nscount; i++)
    _res.nsaddr_list[i].sin_family = AF_INET;

  if (!init_dns_network())
    return 0;

  /* Initialise the hash tables. */
  aseed = time(NULL) ^ (time(NULL) << 3) ^ (u_32bit_t) getpid();
  for (i = 0; i < BASH_SIZE; i++) {
    idbash[i] = NULL;
    ipbash[i] = NULL;
    hostbash[i] = NULL;
  }
  expireresolves = NULL;
  return 1;
}

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static int init_dns_network

(

void

)

[static]

Definition at line 1068 of file coredns.c.

References allocsock, egg_inet_aton, killsock, localhost, LOG_MISC, putlog, resfd, and SOCK_PASS.

Referenced by eof_dns_socket(), and init_dns_core().

{
  int option;
  struct in_addr inaddr;

  resfd = socket(AF_INET, SOCK_DGRAM, 0);
  if (resfd == -1) {
    putlog(LOG_MISC, "*",
           "Unable to allocate socket for nameserver communication: %s",
           strerror(errno));
    return 0;
  }
  if (allocsock(resfd, SOCK_PASS) == -1) {
    putlog(LOG_MISC, "*",
           "Unable to allocate socket in socklist for nameserver communication");
    killsock(resfd);
    return 0;
  }
  option = 1;
  if (setsockopt(resfd, SOL_SOCKET, SO_BROADCAST, (char *) &option,
                 sizeof(option))) {
    putlog(LOG_MISC, "*",
           "Unable to setsockopt() on nameserver communication socket: %s",
           strerror(errno));
    killsock(resfd);
    return 0;
  }

  egg_inet_aton("127.0.0.1", &inaddr);
  localhost = inaddr.s_addr;
  return 1;
}

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static void linkresolve

(

struct resolve *

rp

)

[static]

Definition at line 427 of file coredns.c.

References resolve::expiretime, irp, resolve::next, NULL, and resolve::previous.

Referenced by failrp(), passrp(), and resendrequest().

{
  struct resolve *irp;

  if (expireresolves) {
    irp = expireresolves;
    while ((irp->next) && (rp->expiretime >= irp->expiretime))
      irp = irp->next;
    if (rp->expiretime >= irp->expiretime) {
      rp->next = NULL;
      rp->previous = irp;
      irp->next = rp;
    } else {
      rp->previous = irp->previous;
      rp->next = irp;
      if (irp->previous)
        irp->previous->next = rp;
      else
        expireresolves = rp;
      irp->previous = rp;
    }
  } else {
    rp->next = NULL;
    rp->previous = NULL;
    expireresolves = rp;
  }
}

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static void linkresolvehost

(

struct resolve *

addrp

)

[static]

Definition at line 317 of file coredns.c.

References egg_strcasecmp, gethostbash(), resolve::hostn, resolve::nexthost, NULL, and resolve::previoushost.

Referenced by dns_forward(), and parserespacket().

{
  struct resolve *rp;
  u_32bit_t bashnum;
  int ret;

  bashnum = gethostbash(addrp->hostn);
  rp = hostbash[bashnum];
  if (rp) {
    while ((rp->nexthost) &&
           (egg_strcasecmp(addrp->hostn, rp->nexthost->hostn) < 0))
      rp = rp->nexthost;
    while ((rp->previoushost) &&
           (egg_strcasecmp(addrp->hostn, rp->previoushost->hostn) > 0))
      rp = rp->previoushost;
    ret = egg_strcasecmp(addrp->hostn, rp->hostn);
    if (ret < 0) {
      addrp->previoushost = rp;
      addrp->nexthost = rp->nexthost;
      if (rp->nexthost)
        rp->nexthost->previoushost = addrp;
      rp->nexthost = addrp;
    } else if (ret > 0) {
      addrp->previoushost = rp->previoushost;
      addrp->nexthost = rp;
      if (rp->previoushost)
        rp->previoushost->nexthost = addrp;
      rp->previoushost = addrp;
    } else                        /* Trying to add the same host! */
      return;
  } else
    addrp->nexthost = addrp->previoushost = NULL;
  hostbash[bashnum] = addrp;
}

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static void linkresolveid

(

struct resolve *

addrp

)

[static]

Definition at line 265 of file coredns.c.

References getidbash(), resolve::id, resolve::nextid, NULL, and resolve::previousid.

Referenced by sendrequest().

{
  struct resolve *rp;
  u_32bit_t bashnum;

  bashnum = getidbash(addrp->id);
  rp = idbash[bashnum];
  if (rp) {
    while ((rp->nextid) && (addrp->id > rp->nextid->id))
      rp = rp->nextid;
    while ((rp->previousid) && (addrp->id < rp->previousid->id))
      rp = rp->previousid;
    if (rp->id < addrp->id) {
      addrp->previousid = rp;
      addrp->nextid = rp->nextid;
      if (rp->nextid)
        rp->nextid->previousid = addrp;
      rp->nextid = addrp;
    } else if (rp->id > addrp->id) {
      addrp->previousid = rp->previousid;
      addrp->nextid = rp;
      if (rp->previousid)
        rp->previousid->nextid = addrp;
      rp->previousid = addrp;
    } else                        /* Trying to add the same id! */
      return;
  } else
    addrp->nextid = addrp->previousid = NULL;
  idbash[bashnum] = addrp;
}

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static void linkresolveip

(

struct resolve *

addrp

)

[static]

Definition at line 374 of file coredns.c.

References getipbash(), resolve::ip, resolve::nextip, NULL, and resolve::previousip.

Referenced by dns_lookup(), and parserespacket().

{
  struct resolve *rp;
  u_32bit_t bashnum;

  bashnum = getipbash(addrp->ip);
  rp = ipbash[bashnum];
  if (rp) {
    while ((rp->nextip) && (addrp->ip > rp->nextip->ip))
      rp = rp->nextip;
    while ((rp->previousip) && (addrp->ip < rp->previousip->ip))
      rp = rp->previousip;
    if (rp->ip < addrp->ip) {
      addrp->previousip = rp;
      addrp->nextip = rp->nextip;
      if (rp->nextip)
        rp->nextip->previousip = addrp;
      rp->nextip = addrp;
    } else if (rp->ip > addrp->ip) {
      addrp->previousip = rp->previousip;
      addrp->nextip = rp;
      if (rp->previousip)
        rp->previousip->nextip = addrp;
      rp->previousip = addrp;
    } else                        /* Trying to add the same ip! */
      return;
  } else
    addrp->nextip = addrp->previousip = NULL;
  ipbash[bashnum] = addrp;
}

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static void parserespacket	(	u_8bit_t *	s,
		int	l
	)			[static]

Definition at line 667 of file coredns.c.

References packetheader::ancount, packetheader::arcount, ddebug0, ddebug1, ddebug2, ddebug4, debug0, egg_strcasecmp, failrp(), findid(), getheader_opcode, getheader_qr, getheader_rcode, getheader_tc, HFIXEDSZ, resolve::hostn, HOSTNAMELEN, packetheader::id, resolve::ip, IS_A, IS_PTR, linkresolvehost(), linkresolveip(), my_memcpy, namestring, nmalloc, packetheader::nscount, passrp(), packetheader::qdcount, RES_ERR, RES_MSG, RES_WRN, stackstring, resolve::state, STATE_AREQ, STATE_FAILED, STATE_FINISHED, STATE_PTRREQ, sucknetlong, and sucknetword.

Referenced by dns_ack().

{
  struct resolve *rp;
  packetheader *hp;
  u_8bit_t *eob;
  u_8bit_t *c;
  long ttl;
  int r, usefulanswer;
  u_16bit_t rr, datatype, class, qdatatype, qclass;
  u_8bit_t rdatalength;

  if (l < sizeof(packetheader)) {
    debug0(RES_ERR "Packet smaller than standard header size.");
    return;
  }
  if (l == sizeof(packetheader)) {
    debug0(RES_ERR "Packet has empty body.");
    return;
  }
  hp = (packetheader *) s;
  /* Convert data to host byte order
   *
   * hp->id does not need to be redundantly byte-order flipped, it
   * is only echoed by nameserver
   */
  rp = findid(hp->id);
  if (!rp)
    return;
  if ((rp->state == STATE_FINISHED) || (rp->state == STATE_FAILED))
    return;
  hp->qdcount = ntohs(hp->qdcount);
  hp->ancount = ntohs(hp->ancount);
  hp->nscount = ntohs(hp->nscount);
  hp->arcount = ntohs(hp->arcount);
  if (getheader_tc(hp)) {       /* Packet truncated */
    ddebug0(RES_ERR "Nameserver packet truncated.");
    return;
  }
  if (!getheader_qr(hp)) {      /* Not a reply */
    ddebug0(RES_ERR "Query packet received on nameserver communication "
            "socket.");
    return;
  }
  if (getheader_opcode(hp)) {   /* Not opcode 0 (standard query) */
    ddebug0(RES_ERR "Invalid opcode in response packet.");
    return;
  }
  eob = s + l;
  c = s + HFIXEDSZ;
  switch (getheader_rcode(hp)) {
  case NOERROR:
    if (hp->ancount) {
      ddebug4(RES_MSG "Received nameserver reply. (qd:%u an:%u ns:%u ar:%u)",
              hp->qdcount, hp->ancount, hp->nscount, hp->arcount);
      if (hp->qdcount != 1) {
        ddebug0(RES_ERR "Reply does not contain one query.");
        return;
      }
      if (c > eob) {
        ddebug0(RES_ERR "Reply too short.");
        return;
      }
      switch (rp->state) {      /* Construct expected query reply */
      case STATE_PTRREQ:
        sprintf(stackstring,
                "%u.%u.%u.%u.in-addr.arpa",
                ((u_8bit_t *) & rp->ip)[3],
                ((u_8bit_t *) & rp->ip)[2],
                ((u_8bit_t *) & rp->ip)[1], ((u_8bit_t *) & rp->ip)[0]);
        break;
      case STATE_AREQ:
        strncpy(stackstring, rp->hostn, 1024);
      }
      *namestring = '\0';
      r = dn_expand(s, s + l, c, namestring, MAXDNAME);
      if (r == -1) {
        ddebug0(RES_ERR "dn_expand() failed while expanding query domain.");
        return;
      }
      namestring[strlen(stackstring)] = '\0';
      if (egg_strcasecmp(stackstring, namestring)) {
        ddebug2(RES_MSG "Unknown query packet dropped. (\"%s\" does not "
                "match \"%s\")", stackstring, namestring);
        return;
      }
      ddebug1(RES_MSG "Queried domain name: \"%s\"", namestring);
      c += r;
      if (c + 4 > eob) {
        ddebug0(RES_ERR "Query resource record truncated.");
        return;
      }
      qdatatype = sucknetword(c);
      qclass = sucknetword(c);
      if (qclass != C_IN) {
        ddebug2(RES_ERR "Received unsupported query class: %u (%s)",
                qclass, (qclass < CLASSTYPES_COUNT) ?
                classtypes[qclass] : classtypes[CLASSTYPES_COUNT]);
      }
      switch (qdatatype) {
      case T_PTR:
        if (!IS_PTR(rp)) {
          ddebug0(RES_WRN "Ignoring response with unexpected query type "
                  "\"PTR\".");
          return;
        }
        break;
      case T_A:
        if (!IS_A(rp)) {
          ddebug0(RES_WRN "Ignoring response with unexpected query type "
                  "\"PTR\".");
          return;
        }
        break;
      default:
        ddebug2(RES_ERR "Received unimplemented query type: %u (%s)",
                qdatatype, (qdatatype < RESOURCETYPES_COUNT) ?
                resourcetypes[qdatatype] : resourcetypes[RESOURCETYPES_COUNT]);
      }
      for (rr = hp->ancount + hp->nscount + hp->arcount; rr; rr--) {
        if (c > eob) {
          ddebug0(RES_ERR "Packet does not contain all specified resouce "
                  "records.");
          return;
        }
        *namestring = '\0';
        r = dn_expand(s, s + l, c, namestring, MAXDNAME);
        if (r == -1) {
          ddebug0(RES_ERR "dn_expand() failed while expanding answer domain.");
          return;
        }
        namestring[strlen(stackstring)] = '\0';
        if (egg_strcasecmp(stackstring, namestring))
          usefulanswer = 0;
        else
          usefulanswer = 1;
        ddebug1(RES_MSG "answered domain query: \"%s\"", namestring);
        c += r;
        if (c + 10 > eob) {
          ddebug0(RES_ERR "Resource record truncated.");
          return;
        }
        datatype = sucknetword(c);
        class = sucknetword(c);
        ttl = sucknetlong(c);
        rdatalength = sucknetword(c);
        if (class != qclass) {
          ddebug2(RES_MSG "query class: %u (%s)",
                  qclass, (qclass < CLASSTYPES_COUNT) ?
                  classtypes[qclass] : classtypes[CLASSTYPES_COUNT]);
          ddebug2(RES_MSG "rr class: %u (%s)", class,
                  (class < CLASSTYPES_COUNT) ?
                  classtypes[class] : classtypes[CLASSTYPES_COUNT]);
          ddebug0(RES_ERR "Answered class does not match queried class.");
          return;
        }
        if (!rdatalength) {
          ddebug0(RES_ERR "Zero size rdata.");
          return;
        }
        if (c + rdatalength > eob) {
          ddebug0(RES_ERR "Specified rdata length exceeds packet size.");
          return;
        }
        if (datatype == qdatatype) {
          ddebug1(RES_MSG "TTL: %s", strtdiff(sendstring, ttl));
          ddebug1(RES_MSG "TYPE: %s", (datatype < RESOURCETYPES_COUNT) ?
                  resourcetypes[datatype] :
                  resourcetypes[RESOURCETYPES_COUNT]);
          if (usefulanswer)
            switch (datatype) {
            case T_A:
              if (rdatalength != 4) {
                ddebug1(RES_ERR "Unsupported rdata format for \"A\" type. "
                        "(%u bytes)", rdatalength);
                return;
              }
              my_memcpy(&rp->ip, (IP *) c, sizeof(IP));
              linkresolveip(rp);
              passrp(rp, ttl, T_A);
              return;
            case T_PTR:
              *namestring = '\0';
              r = dn_expand(s, s + l, c, namestring, MAXDNAME);
              if (r == -1) {
                ddebug0(RES_ERR "dn_expand() failed while expanding domain in "
                        "rdata.");
                return;
              }
              ddebug1(RES_MSG "Answered domain: \"%s\"", namestring);
              if (r > HOSTNAMELEN) {
                ddebug0(RES_ERR "Domain name too long.");
                failrp(rp, T_PTR);
                return;
              }
              if (!rp->hostn) {
                rp->hostn = nmalloc(strlen(namestring) + 1);
                strcpy(rp->hostn, namestring);
                linkresolvehost(rp);
                passrp(rp, ttl, T_PTR);
                return;
              }
              break;
            default:
              ddebug2(RES_ERR "Received unimplemented data type: %u (%s)",
                      datatype, (datatype < RESOURCETYPES_COUNT) ?
                      resourcetypes[datatype] :
                      resourcetypes[RESOURCETYPES_COUNT]);
            }
        } else if (datatype == T_CNAME) {
          *namestring = '\0';
          r = dn_expand(s, s + l, c, namestring, MAXDNAME);
          if (r == -1) {
            ddebug0(RES_ERR "dn_expand() failed while expanding domain in "
                    "rdata.");
            return;
          }
          ddebug1(RES_MSG "answered domain is CNAME for: %s", namestring);
          /* The next responses will be related to the domain
           * pointed to by CNAME, so we need to update which
           * respones we regard as important.
           */
          strncpy(stackstring, namestring, 1024);
        } else {
          ddebug2(RES_MSG "Ignoring resource type %u. (%s)",
                  datatype, (datatype < RESOURCETYPES_COUNT) ?
                  resourcetypes[datatype] :
                  resourcetypes[RESOURCETYPES_COUNT]);
        }
        c += rdatalength;
      }
    } else
      ddebug0(RES_ERR "No error returned but no answers given.");
    break;
  case NXDOMAIN:
    ddebug0(RES_MSG "Host not found.");
    switch (rp->state) {
    case STATE_PTRREQ:
      failrp(rp, T_PTR);
      break;
    case STATE_AREQ:
      failrp(rp, T_A);
      break;
    default:
      failrp(rp, 0);
      break;
    }
    break;
  default:
    ddebug2(RES_MSG "Received error response %u. (%s)",
            getheader_rcode(hp), (getheader_rcode(hp) < RESPONSECODES_COUNT) ?
            responsecodes[getheader_rcode(hp)] :
            responsecodes[RESPONSECODES_COUNT]);
  }
}

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static void passrp	(	struct resolve *	rp,
		long	ttl,
		int	type
	)			[static]

Definition at line 647 of file coredns.c.

References ddebug1, dns_cache, dns_event_success(), resolve::expiretime, resolve::hostn, linkresolve(), now, RES_MSG, resolve::state, STATE_FINISHED, time_t, and untieresolve().

Referenced by parserespacket().

{
  rp->state = STATE_FINISHED;

  /* Do not cache entries for too long. */
  if (ttl < dns_cache)
    rp->expiretime = now + (time_t) ttl;
  else
    rp->expiretime = now + dns_cache;

  /* Expire time was changed, reinsert entry to maintain order */
  untieresolve(rp);
  linkresolve(rp);

  ddebug1(RES_MSG "Lookup successful: %s", rp->hostn);
  dns_event_success(rp, type);
}

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static void resendrequest	(	struct resolve *	rp,
		int	type
	)			[static]

Definition at line 590 of file coredns.c.

References ddebug1, dns_retrydelay, dorequest(), resolve::expiretime, resolve::hostn, resolve::id, resolve::ip, iptostr, linkresolve(), now, RES_MSG, resolve::sends, and tempstring.

Referenced by dns_check_expires(), and sendrequest().

{
  rp->sends++;
  /* Update expire time */
  rp->expiretime = now + (dns_retrydelay * rp->sends);
  /* Add (back) to expire list */
  linkresolve(rp);

  if (type == T_A) {
    dorequest(rp->hostn, type, rp->id);
    ddebug1(RES_MSG "Sent domain lookup request for \"%s\".", rp->hostn);
  } else if (type == T_PTR) {
    sprintf(tempstring, "%u.%u.%u.%u.in-addr.arpa",
            ((u_8bit_t *) & rp->ip)[3],
            ((u_8bit_t *) & rp->ip)[2],
            ((u_8bit_t *) & rp->ip)[1], ((u_8bit_t *) & rp->ip)[0]);
    dorequest(tempstring, type, rp->id);
    ddebug1(RES_MSG "Sent domain lookup request for \"%s\".", iptostr(rp->ip));
  }
}

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static void sendrequest	(	struct resolve *	rp,
		int	type
	)			[static]

Definition at line 613 of file coredns.c.

References aseed, findid(), resolve::id, idseed, linkresolveid(), NULL, and resendrequest().

Referenced by dns_forward(), and dns_lookup().

{
  /* Create unique id */
  do {
    idseed = (((idseed + idseed) | (long) time(NULL))
              + idseed - 0x54bad4a) ^ aseed;
    aseed ^= idseed;
    rp->id = (u_16bit_t) idseed;
  } while (findid(rp->id));
  linkresolveid(rp);            /* Add id to id hash table */
  resendrequest(rp, type);      /* Send request */
}

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static void unlinkresolve

(

struct resolve *

rp

)

[static]

Definition at line 470 of file coredns.c.

References resolve::hostn, nfree, unlinkresolvehost(), unlinkresolveid(), unlinkresolveip(), and untieresolve().

Referenced by dns_check_expires().

{

  untieresolve(rp);             /* Not really needed. Left in to be on the
                                 * safe side. */
  unlinkresolveid(rp);
  unlinkresolveip(rp);
  if (rp->hostn)
    unlinkresolvehost(rp);
  nfree(rp);
}

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static void unlinkresolvehost

(

struct resolve *

rp

)

[static]

Definition at line 354 of file coredns.c.

References gethostbash(), resolve::hostn, resolve::nexthost, nfree, and resolve::previoushost.

Referenced by unlinkresolve().

{
  u_32bit_t bashnum;

  bashnum = gethostbash(rp->hostn);
  if (hostbash[bashnum] == rp) {
    if (rp->previoushost)
      hostbash[bashnum] = rp->previoushost;
    else
      hostbash[bashnum] = rp->nexthost;
  }
  if (rp->nexthost)
    rp->nexthost->previoushost = rp->previoushost;
  if (rp->previoushost)
    rp->previoushost->nexthost = rp->nexthost;
  nfree(rp->hostn);
}

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static void unlinkresolveid

(

struct resolve *

rp

)

[static]

Definition at line 298 of file coredns.c.

References getidbash(), resolve::id, resolve::nextid, and resolve::previousid.

Referenced by unlinkresolve().

{
  u_32bit_t bashnum;

  bashnum = getidbash(rp->id);
  if (idbash[bashnum] == rp) {
    if (rp->previousid)
      idbash[bashnum] = rp->previousid;
    else
      idbash[bashnum] = rp->nextid;
  }
  if (rp->nextid)
    rp->nextid->previousid = rp->previousid;
  if (rp->previousid)
    rp->previousid->nextid = rp->nextid;
}

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static void unlinkresolveip

(

struct resolve *

rp

)

[static]

Definition at line 407 of file coredns.c.

References getipbash(), resolve::ip, resolve::nextip, and resolve::previousip.

Referenced by unlinkresolve().

{
  u_32bit_t bashnum;

  bashnum = getipbash(rp->ip);
  if (ipbash[bashnum] == rp) {
    if (rp->previousip)
      ipbash[bashnum] = rp->previousip;
    else
      ipbash[bashnum] = rp->nextip;
  }
  if (rp->nextip)
    rp->nextip->previousip = rp->previousip;
  if (rp->previousip)
    rp->previousip->nextip = rp->nextip;
}

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static void untieresolve

(

struct resolve *

rp

)

[static]

Definition at line 457 of file coredns.c.

References resolve::next, and resolve::previous.

Referenced by dns_check_expires(), failrp(), passrp(), and unlinkresolve().

{
  if (rp->previous)
    rp->previous->next = rp->next;
  else
    expireresolves = rp->next;
  if (rp->next)
    rp->next->previous = rp->previous;
}

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---

Variable Documentation

long aseed [static]

Definition at line 169 of file coredns.c.

Referenced by init_dns_core(), and sendrequest().

struct resolve* expireresolves = 0 [static]

Definition at line 164 of file coredns.c.

Referenced by dns_cache_expmem(), and dns_free_cache().

struct resolve* hostbash[8192] [static]

Definition at line 163 of file coredns.c.

struct resolve* idbash[8192] [static]

Definition at line 161 of file coredns.c.

long idseed = 0xdeadbeef [static]

Definition at line 168 of file coredns.c.

Referenced by sendrequest().

struct resolve* ipbash[8192] [static]

Definition at line 162 of file coredns.c.

IP localhost [static]

Definition at line 166 of file coredns.c.

Referenced by dns_ack(), and init_dns_network().

char namestring[1024+1] [static]

Definition at line 174 of file coredns.c.

Referenced by parserespacket().

const char nullstring[] = "" [static]

Definition at line 181 of file coredns.c.

int resfd [static]

Definition at line 171 of file coredns.c.

Referenced by dns_ack(), dns_close(), dns_start(), dorequest(), eof_dns_socket(), and init_dns_network().

u_32bit_t resrecvbuf[((PACKETSZ)+7) >> 2] [static]

Definition at line 159 of file coredns.c.

Referenced by dns_ack().

char stackstring[1024+1] [static]

Definition at line 175 of file coredns.c.

Referenced by parserespacket().

char tempstring[512] [static]

Definition at line 173 of file coredns.c.

Referenced by resendrequest().