X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/adns/blobdiff_plain/964344fc6da09bb76aff991cbda338fe9c919d21..84fe28dbf1b4d178b54d84becc0ee91c1b2db5d4:/src/adns.c

diff --git a/src/adns.c b/src/adns.c
index 210c256..31a64dc 100644
--- a/src/adns.c
+++ b/src/adns.c
@@ -5,7 +5,10 @@
 #include <errno.h>
 #include <string.h>
 #include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
 
+#include <netdb.h>
 #include <arpa/nameser.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
@@ -13,22 +16,25 @@
 
 #include "adns-internal.h"
 
-#define LIST_UNLINK(list,node) \
+#define LIST_UNLINK_PART(list,node,part) \
   do { \
-    if ((node)->back) (node)->back->next= (node)->next; \
-      else                   (list).head= (node)->next; \
-    if ((node)->next) (node)->next->back= (node)->back; \
-      else                   (list).tail= (node)->back; \
+    if ((node)->back) (node)->back->part next= (node)->part next; \
+      else                        (list).head= (node)->part next; \
+    if ((node)->next) (node)->next->part back= (node)->part back; \
+      else                        (list).tail= (node)->part back; \
   } while(0)
 
-#define LIST_LINK_TAIL(list,node) \
+#define LIST_LINK_TAIL_PART(list,node,part) \
   do { \
-    (node)->back= 0; \
-    (node)->next= (list).tail; \
-    if ((list).tail) (list).tail->back= (node); else (list).head= (node); \
+    (node)->part back= 0; \
+    (node)->part next= (list).tail; \
+    if ((list).tail) (list).tail->part back= (node); else (list).part head= (node); \
     (list).tail= (node); \
   } while(0)
 
+#define LIST_UNLINK(list,node) LIST_UNLINK_PART(list,node,)
+#define LIST_LINK_TAIL_PART(list,node) LIST_LINK_TAIL(list,node,)
+
 static void vdebug(adns_state ads, const char *fmt, va_list al) {
   if (!(ads->iflags & adns_if_debug)) return;
   fputs("adns debug: ",stderr);
@@ -60,13 +66,26 @@ static void diag(adns_state ads, const char *fmt, ...) {
 }
 
 static void addserver(adns_state ads, struct in_addr addr) {
+  int i;
+  struct server *ss;
+  
+  for (i=0; i<ads->nservers; i++) {
+    if (ads->servers[i].addr.s_addr == addr.s_addr) {
+      debug(ads,"duplicate nameserver %s ignored",inet_ntoa(addr));
+      return;
+    }
+  }
+  
   if (ads->nservers>=MAXSERVERS) {
     diag(ads,"too many nameservers, ignoring %s",inet_ntoa(addr));
-  } else {
-    ads->servers[ads->nservers].addr= addr;
-    ads->servers[ads->nservers].tcpsocket= -1;
-    ads->nservers++;
+    return;
   }
+
+  ss= ads->servers+ads->nservers;
+  ss->addr= addr;
+  ss->state= server_disc;
+  ss->connw.head= ss->connw.tail= 0;
+  ads->nservers++;
 }
 
 static void configparseerr(adns_state ads, const char *fn, int lno,
@@ -124,9 +143,8 @@ static const struct configcommandinfo {
   {  0                                   }
 };
 
-static int whitespace(int c) {
-  return c==' ' || c=='\n' || c=='\t';
-}
+static int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; }
+static int ctype_digit(int c) { return c>='0' && c<='9'; }
 
 static void readconfig(adns_state ads, const char *filename) {
   char linebuf[2000], *p, *q;
@@ -153,13 +171,13 @@ static void readconfig(adns_state ads, const char *filename) {
       if (c == EOF) break;
       continue;
     }
-    while (l>0 && whitespace(linebuf[l-1])) l--;
+    while (l>0 && ctype_whitespace(linebuf[l-1])) l--;
     linebuf[l]= 0;
     p= linebuf;
-    while (whitespace(*p)) p++;
+    while (ctype_whitespace(*p)) p++;
     if (*p == '#' || *p == '\n') continue;
     q= p;
-    while (*q && !whitespace(*q)) q++;
+    while (*q && !ctype_whitespace(*q)) q++;
     for (ccip=configcommandinfos;
 	 ccip->name && strncmp(ccip->name,p,q-p);
 	 ccip++);
@@ -167,7 +185,7 @@ static void readconfig(adns_state ads, const char *filename) {
       diag(ads,"%s:%d: unknown configuration directive `%.*s'",filename,lno,q-p,p);
       continue;
     }
-    while (whitespace(*q)) q++;
+    while (ctype_whitespace(*q)) q++;
     ccip->fn(ads,filename,lno,q);
   }
   if (ferror(file)) {
@@ -180,8 +198,8 @@ static const char *instrum_getenv(adns_state ads, const char *envvar) {
   const char *value;
 
   value= getenv(envvar);
-  if (!value) debug(ads,"environment variable `%s' not set",envvar);
-  else debug(ads,"environment variable `%s' set to `%s'",envvar,value);
+  if (!value) debug(ads,"environment variable %s not set",envvar);
+  else debug(ads,"environment variable %s set to `%s'",envvar,value);
   return value;
 }
 
@@ -199,12 +217,15 @@ static void readconfigenv(adns_state ads, const char *envvar) {
 int adns_init(adns_state *ads_r, adns_initflags flags) {
   adns_state ads;
   const char *res_options, *adns_res_options;
+  struct protoent *proto;
+  int r;
   
   ads= malloc(sizeof(*ads)); if (!ads) return errno;
-  ads->input.head= ads->input.tail= 0;
+  ads->tosend.head= ads->tosend.tail= 0;
   ads->timew.head= ads->timew.tail= 0;
   ads->childw.head= ads->childw.tail= 0;
   ads->output.head= ads->output.tail= 0;
+  ads->nextid= 0x311f;
   ads->udpsocket= -1;
   ads->qbufavail= 0;
   ads->qbuf= 0;
@@ -236,13 +257,23 @@ int adns_init(adns_state *ads_r, adns_initflags flags) {
     ia.s_addr= INADDR_LOOPBACK;
     addserver(ads,ia);
   }
+
+  proto= getprotobyname("udp"); if (!proto) { r= ENOPROTOOPT; goto x_free; }
+  ads->udpsocket= socket(AF_INET,SOCK_DGRAM,proto->p_proto);
+  if (!ads->udpsocket) { r= errno; goto x_closeudp; }
   
   *ads_r= ads;
   return 0;
+
+ x_closeudp:
+  close(ads->udpsocket);
+ x_free:
+  free(ads);
+  return r;
 }
 
 static void query_fail(adns_state ads, adns_query qu, adns_status stat) {
-  struct adns_answer *ans;
+  adns_answer *ans;
   
   ans= qu->answer;
   if (!ans) ans= malloc(sizeof(*qu->answer));
@@ -253,45 +284,391 @@ static void query_fail(adns_state ads, adns_query qu, adns_status stat) {
     ans->nrrs= 0;
   }
   qu->answer= ans;
-  LIST_LINK_TAIL(ads->input,qu);
+  qu->id= -1;
+  LIST_LINK_TAIL(ads->output,qu);
 }
 
-void adns_interest(adns_state ads,
-		   fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
-		   int *maxfd, struct timeval **tv_io, struct timeval *tvbuf) {
+int adns_finish(adns_state ads) {
   abort(); /* FIXME */
 }
 
-int adns_submit(adns_state ads,
-		const char *owner,
-		adns_rrtype type,
-		int flags,
-		void *context,
-		adns_query *query_r) {
+static void autosys(adns_state ads, struct timeval now) {
+  if (ads->iflags & adns_if_noautosys) return;
+  adns_callback(ads,-1,0,0,0);
+}
+
+void adns_cancel(adns_state ads, adns_query query) {
+  abort(); /* FIXME */
+}
+
+int adns_callback(adns_state ads, int maxfd,
+		  const fd_set *readfds, const fd_set *writefds,
+		  const fd_set *exceptfds) {
+  abort(); /* FIXME */
+}
+
+static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf,
+			struct timeval maxto) {
+  struct timeval rbuf;
+
+  rbuf= *tv_io;
+  if (!rbuf) { *tvbuf= maxto; *tv_io= tvbuf; return; }
+  if (timercmp(rbuf,&maxto,>)) *rbuf= maxto;
+}
+
+static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf,
+			   struct timeval now, struct timeval maxtime) {
+  ldiv_t dr;
+  
+  maxtime.tv_sec -= (now.tv_sec-1);
+  maxtime.tv_usec += (1000-now.tv_usec);
+  dr= ldiv(maxtime.tv_usec,1000);
+  maxtime.tv_sec += dr.quot;
+  maxtime.tv_usec -= dr.rem;
+  inter_maxto(tv_io,tvbuf,maxtime);
+}
+
+static void localresourcerr(struct timeval **tv_io, struct timeval *tvbuf,
+			    const char *syscall) {
+  struct timeval tvto_lr;
+  
+  diag(ads,"local system resources scarce (during %s): %s",syscall,strerror(errno));
+  timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS);
+  inter_maxto(tv_io, tvbuf, tvto_lr);
+  return;
+}
+
+static inline void timevaladd(struct timeval *tv_io, long ms) {
+  struct timeval tmp;
+  assert(ms>=0);
+  tmp= *tv_io;
+  tmp.tv_usec += (ms%1000)*1000;
+  tmp.tv_sec += ms/1000;
+  if (tmp.tv_usec >= 1000) { tmp.tv_sec++; tmp.tv_usec -= 1000; }
+  *tv_io= tmp;
+}    
+
+void adns_interest(adns_state ads, int *maxfd,
+		   fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+		   struct timeval **tv_io, struct timeval *tvbuf) {
+  struct timeval now;
   adns_query qu;
-  adns_status stat;
-  int ol;
+  int r;
+  
+  r= gettimeofday(&now,0);
+  if (r) { localresourcerr(tv_io,tvbuf,"gettimeofday"); return; }
+
+  for (qu= ads->timew; qu; qu= nqu) {
+    nqu= qu->next;
+    if (timercmp(&now,qu->timeout,>)) {
+      DLIST_UNLINK(ads->timew,qu);
+      if (qu->nextudpserver == -1) {
+	query_fail(ads,qu,adns_s_notresponding);
+      } else {
+	DLIST_LINKTAIL(ads->tosend,qu);
+      }
+    } else {
+      inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
+    }
+  }
+  
+  for (qu= ads->tosend; qu; qu= nqu) {
+    nqu= qu->next;
+    quproc_tosend(ads,qu,now);
+  }
 
-  stat= 0;
-  ol= strlen(owner);
-  if (ol>MAXDNAME+1) { stat= adns_s_invaliddomain; ol= 0; }
-  if (ol>0 && owner[ol-1]=='.') { flags &= ~adns_f_search; ol--; }
-  qu= malloc(sizeof(*qu)+ol+1); if (!qu) return errno;
-  qu->next= qu->back= qu->parent= qu->child= 0;
+  for (qu= ads->timew; qu; qu= qu->next) {
+    if (qu->sentudp) {
+      inter_addfd(maxfd,readfds,ads->udpsocket);
+      break;
+    }
+  }
+  switch (ads->tcpstate) {
+  case server_disc:
+    break;
+  case server_connecting:
+    inter_addfd(maxfd,readfds,ads->tcpsocket);
+    inter_addfd(maxfd,writefds,ads->tcpsocket);
+    inter_addfd(maxfd,exceptfds,ads->tcpsocket);
+    break;
+  case server_connected:
+    inter_addfd(maxfd,readfds,ads->tcpsocket);
+    inter_addfd(maxfd,exceptfds,ads->tcpsocket);
+    if (ads->opbufused) inter_addfd(maxfd,writefds,ads->tcpsocket);
+  default:
+    abort();
+  }
+  
+}
+
+static int internal_check(adns_state ads,
+			  adns_query *query_io,
+			  adns_answer **answer,
+			  void **context_r) {
+  adns_query qu;
+
+  qu= *query_io;
+  if (!qu) {
+    if (!ads->output.head) return EWOULDBLOCK;
+    qu= ads->output.head;
+  } else {
+    if (qu->id>=0) return EWOULDBLOCK;
+  }
+  LIST_UNLINK(ads->output,qu);
+  *answer= qu->answer;
+  if (context_r) *context_r= qu->context;
+  free(qu);
+  return 0;
+}
+
+int adns_wait(adns_state ads,
+	      adns_query *query_io,
+	      adns_answer **answer_r,
+	      void **context_r) {
+  int r, maxfd, rsel, rcb;
+  fd_set readfds, writefds, exceptfds;
+  struct timeval tvbuf, *tvp;
+  
+  for (;;) {
+    r= internal_check(ads,query_io,answer_r,context_r);
+    if (r && r != EWOULDBLOCK) return r;
+    FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
+    maxfd= 0; tvp= 0;
+    adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf);
+    rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
+    if (rsel==-1) return r;
+    rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds);
+    assert(rcb==rsel);
+  }
+}
+
+int adns_check(adns_state ads,
+	       adns_query *query_io,
+	       adns_answer **answer_r,
+	       void **context_r) {
+  autosys(ads);
+  return internal_check(ads,query_io,answer_r,context_r);
+}
+
+int adns_synchronous(adns_state ads,
+		     const char *owner,
+		     adns_rrtype type,
+		     adns_queryflags flags,
+		     adns_answer **answer_r) {
+  adns_query qu;
+  int r;
+  
+  r= adns_submit(ads,owner,type,flags,0,&qu);
+  if (r) return r;
+
+  do {
+    r= adns_wait(ads,&qu,answer_r,0);
+  } while (r==EINTR);
+  if (r) adns_cancel(ads,qu);
+  return r;
+}
+
+static adns_status mkquery(adns_state ads, const char *owner, int ol, int id,
+			   adns_rrtype type, adns_queryflags flags, int *qml_r) {
+  int ll, c, nlabs, qbufreq;
+  unsigned char label[255], *nqbuf;
+  const char *p, *pe;
+
+#define MKQUERY_ADDB(b) *nqbuf++= (b)
+#define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
+
+  qbufreq= 12+strlen(owner)+3;
+  if (ads->qbufavail < qbufreq) {
+    nqbuf= realloc(ads->qbuf,qbufreq);
+    if (!nqbuf) return adns_s_nolocalmem;
+    ads->qbuf= nqbuf; ads->qbufavail= qbufreq;
+  }
+  nqbuf= ads->qbuf;
+  
+  MKQUERY_ADDW(id);
+  MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
+  MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
+  MKQUERY_ADDW(1); /* QDCOUNT=1 */
+  MKQUERY_ADDW(0); /* ANCOUNT=0 */
+  MKQUERY_ADDW(0); /* NSCOUNT=0 */
+  MKQUERY_ADDW(0); /* ARCOUNT=0 */
+  p= owner; pe= owner+ol;
+  nlabs= 0;
+  if (!*p) return adns_s_invaliddomain;
+  do {
+    ll= 0;
+    while (p!=pe && (c= *p++)!='.') {
+      if (c=='\\') {
+	if (!(flags & adns_f_anyquote)) return adns_s_invaliddomain;
+	if (ctype_digit(p[0])) {
+	  if (ctype_digit(p[1]) && ctype_digit(p[2])) {
+	    c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
+	    if (c >= 256) return adns_s_invaliddomain;
+	  } else {
+	    return adns_s_invaliddomain;
+	  }
+	} else if (!(c= *p++)) {
+	  return adns_s_invaliddomain;
+	}
+      }
+      if (!(flags & adns_f_anyquote)) {
+	if ((c >= '0' && c <= '9') || c == '-') {
+	  if (!ll) return adns_s_invaliddomain;
+	} else if ((c < 'a' || c > 'z') && (c < 'A' && c > 'Z')) {
+	  return adns_s_invaliddomain;
+	}
+      }
+      if (ll == sizeof(label)) return adns_s_invaliddomain;
+      label[ll++]= c;
+    }
+    if (!ll) return adns_s_invaliddomain;
+    if (nlabs++ > 63) return adns_s_invaliddomain;
+    MKQUERY_ADDB(ll);
+    memcpy(nqbuf,label,ll); nqbuf+= ll;
+  } while (p!=pe);
+
+  MKQUERY_ADDB(0);
+  MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
+  MKQUERY_ADDW(1); /* QCLASS=IN */
+
+  *qml_r= nqbuf - ads->qbuf;
+  
+  return adns_s_ok;
+}
+
+static adns_query allocquery(adns_state ads, const char *owner, int ol,
+			     int qml, int id, adns_rrtype type,
+			     adns_queryflags flags, void *context) {
+  adns_query qu;
+  unsigned char *qm;
+  
+  qu= malloc(sizeof(*qu)+ol+1+qml); if (!qu) return 0;
+  qu->next= qu->back= qu->parent= 0;
+  qu->children.head= qu->children.tail= 0;
+  qu->siblings.next= qu->siblings.back= 0;
+  qu->id= id;
   qu->type= type;
   qu->answer= 0;
   qu->flags= flags;
   qu->context= context;
   qu->udpretries= 0;
-  qu->server= 0;
+  qu->sentudp= qu->senttcp= 0;
+  qu->nextserver= 0;
   memcpy(qu->owner,owner,ol); qu->owner[ol]= 0;
-  if (stat) {
-    query_fail(ads,qu,stat);
-  } else {
-    LIST_LINK_TAIL(ads->input,qu);
-    adns_interest(ads,0,0,0,0,0,0);
-  }
+  qu->querymsg= qm= qu->owner+ol+1;
+  memcpy(qm,ads->qbuf,qml);
+  qu->querylen= qml;
+  return qu;
+}
+
+static int failsubmit(adns_state ads, void *context, adns_query *query_r,
+		      adns_rrtype type, adns_queryflags flags,
+		      int id, adns_status stat) {
+  adns_query qu;
+
+  qu= allocquery(ads,0,0,0,id,type,flags,context); if (!qu) return errno;
+  query_fail(ads,qu,stat);
   *query_r= qu;
+  return 0;
+}
 
-  abort(); /* FIXME */
+static void quproc_tosend(adns_state ads, adns_query qu, struct timeval now) {
+  /* Query must be on the `tosend' queue, and guarantees to remove it. */
+  struct sockaddr_in servaddr;
+  int serv;
+
+  if (qu->nextudpserver != -1) {
+    if (qu->udpretries >= UDPMAXRETRIES) {
+      DLIST_UNLINK(ads->tosend,qu);
+      query_fail(ads,qu,adns_s_notresponding);
+      return;
+    }
+    serv= qu->nextudpserver;
+    memset(&servaddr,0,sizeof(servaddr));
+    servaddr.sin_family= AF_INET;
+    servaddr.sin_addr= ads->servers[serv].addr;
+    servaddr.sin_port= htons(53);
+    r= sendto(ads->udpsocket,qu->querymsg,qu->querylen,0,&servaddr,sizeof(servaddr));
+    if (r<0 && errno == EMSGSIZE) {
+      qu->nextudpserver= -1;
+    } else {
+      if (r<0) {
+	diag("sendto %s failed: %s",inet_ntoa(servaddr.sin_addr),strerror(errno));
+      }
+      DLIST_UNLINK(ads->tosend,qu);
+      timevaladd(&now,UDPRETRYMS);
+      qu->timeout= now;
+      qu->sentudp |= (1<<serv);
+      qu->nextudpserver= (serv+1)%ads->nservers;
+      qu->udpretries++;
+      DLIST_LINKTAIL(ads->timew,qu);
+      return;
+    }
+  }
+
+  for (;;) {
+    serv= tcpserver_get(ads);
+    if (serv<0) { r=0; break; }
+    if (ads->opbufused) { r=0; break; }
+    r= write(ads->tcpsocket,qu->querymsg,qu->querylen);
+    if (r >= 0) break;
+    if (errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
+	errno == ENOBUFS || errno == ENOMEM) {
+      r= 0; break;
+    }
+    tcpserver_broken(serv);
+  }
+  if (r < qu->querylen) {
+    newopbufused= qu->opbufused + (qu->querylen-r);
+    if (newopbufused > ads->opbufavail) {
+      newopbufavail= ads->newopbufused<<1;
+      newopbuf= realloc(newopbufavail);
+      if (!newopbuf) {
+	DLIST_UNLINK(ads->tosend,qu);
+	query_fail(ads,qu,adns_s_nolocalmem);
+	return;
+      }
+      ads->opbuf= newopbuf;
+      ads->opbufavail= newopbufavail;
+    }
+    memcpy(ads->opbuf+ads->opbufused,qu->querymsg+r,qu->querylen-r);
+    ads->opbufused= newopbufused;
+  }
+  DLIST_UNLINK(ads->tosend,qu);
+  timevaladd(&now,TCPMS);
+  qu->timeout= now;
+  qu->senttcp |= (1<<qu->nextserver);
+  DLIST_LINKTAIL(ads->timew,qu);
+}
+
+int adns_submit(adns_state ads,
+		const char *owner,
+		adns_rrtype type,
+		adns_queryflags flags,
+		void *context,
+		adns_query *query_r) {
+  adns_query qu;
+  adns_status stat;
+  int ol, id, qml;
+
+  id= ads->nextid++;
+
+  ol= strlen(owner);
+  if (ol<=1 || ol>MAXDNAME+1)
+    return failsubmit(ads,context,query_r,type,flags,id,adns_s_invaliddomain);
+  if (owner[ol-1]=='.' && owner[ol-2]!='\\') { flags &= ~adns_f_search; ol--; }
+
+  stat= mkquery(ads,owner,ol,id,type,flags,&qml);
+  if (stat) return failsubmit(ads,context,query_r,type,flags,id,stat);
+
+  qu= allocquery(ads,owner,ol,qml,id,type,flags,context); if (!qu) return errno;
+  if (qu->flags & adns_f_usevc) qu->udpretries= -1;
+  LIST_LINK_TAIL(ads->tosend,qu);
+    
+  r= gettimeofday(&now,0); if (r) return;
+  quproc_tosend(ads,qu,now);
+  autosys(ads,now);
+
+  *query_r= qu;
+  return 0;
 }