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authorWerner Koch <wk@gnupg.org>2006-08-16 12:47:53 +0200
committerWerner Koch <wk@gnupg.org>2006-08-16 12:47:53 +0200
commitb744f963d7061ce55d2eed65b281298476e54fb7 (patch)
tree6e8ccb3c39a45c16b4ca6cdb2273eb3b8bc2a888 /common/srv.c
parentChanged HTTP API. (diff)
downloadgnupg2-b744f963d7061ce55d2eed65b281298476e54fb7.tar.xz
gnupg2-b744f963d7061ce55d2eed65b281298476e54fb7.zip
With --enable-gpg the keyservers are now build and a first test using gpg2
shows no prblems. Needs more testing of course.
Diffstat (limited to 'common/srv.c')
-rw-r--r--common/srv.c257
1 files changed, 257 insertions, 0 deletions
diff --git a/common/srv.c b/common/srv.c
new file mode 100644
index 000000000..386e5e459
--- /dev/null
+++ b/common/srv.c
@@ -0,0 +1,257 @@
+/* srv.c - DNS SRV code
+ * Copyright (C) 2003 Free Software Foundation, Inc.
+ *
+ * This file is part of GNUPG.
+ *
+ * GNUPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GNUPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * USA.
+ */
+
+#include <config.h>
+#include <sys/types.h>
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+#endif
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "util.h"
+#include "srv.h"
+
+/* Not every installation has gotten around to supporting SRVs
+ yet... */
+#ifndef T_SRV
+#define T_SRV 33
+#endif
+
+static int
+priosort(const void *a,const void *b)
+{
+ const struct srventry *sa=a,*sb=b;
+ if(sa->priority>sb->priority)
+ return 1;
+ else if(sa->priority<sb->priority)
+ return -1;
+ else
+ return 0;
+}
+
+int
+getsrv(const char *name,struct srventry **list)
+{
+ unsigned char answer[PACKETSZ];
+ int r,srvcount=0;
+ unsigned char *pt,*emsg;
+ u16 count,dlen;
+
+ *list=NULL;
+
+ r=res_query(name,C_IN,T_SRV,answer,PACKETSZ);
+ if(r<sizeof(HEADER) || r>PACKETSZ)
+ return -1;
+
+ if((((HEADER *)answer)->rcode)==NOERROR &&
+ (count=ntohs(((HEADER *)answer)->ancount)))
+ {
+ int i,rc;
+
+ emsg=&answer[r];
+ pt=&answer[sizeof(HEADER)];
+
+ /* Skip over the query */
+
+ rc=dn_skipname(pt,emsg);
+ if(rc==-1)
+ goto fail;
+
+ pt+=rc+QFIXEDSZ;
+
+ while(count-->0 && pt<emsg)
+ {
+ struct srventry *srv=NULL;
+ u16 type,class;
+
+ *list=xrealloc(*list,(srvcount+1)*sizeof(struct srventry));
+ memset(&(*list)[srvcount],0,sizeof(struct srventry));
+ srv=&(*list)[srvcount];
+ srvcount++;
+
+ rc=dn_skipname(pt,emsg); /* the name we just queried for */
+ if(rc==-1)
+ goto fail;
+ pt+=rc;
+
+ /* Truncated message? */
+ if((emsg-pt)<16)
+ goto fail;
+
+ type=*pt++ << 8;
+ type|=*pt++;
+ /* We asked for SRV and got something else !? */
+ if(type!=T_SRV)
+ goto fail;
+
+ class=*pt++ << 8;
+ class|=*pt++;
+ /* We asked for IN and got something else !? */
+ if(class!=C_IN)
+ goto fail;
+
+ pt+=4; /* ttl */
+ dlen=*pt++ << 8;
+ dlen|=*pt++;
+ srv->priority=*pt++ << 8;
+ srv->priority|=*pt++;
+ srv->weight=*pt++ << 8;
+ srv->weight|=*pt++;
+ srv->port=*pt++ << 8;
+ srv->port|=*pt++;
+
+ /* Get the name. 2782 doesn't allow name compression, but
+ dn_expand still works to pull the name out of the
+ packet. */
+ rc=dn_expand(answer,emsg,pt,srv->target,MAXDNAME);
+ if(rc==1 && srv->target[0]==0) /* "." */
+ goto noanswer;
+ if(rc==-1)
+ goto fail;
+ pt+=rc;
+ /* Corrupt packet? */
+ if(dlen!=rc+6)
+ goto fail;
+
+#if 0
+ printf("count=%d\n",srvcount);
+ printf("priority=%d\n",srv->priority);
+ printf("weight=%d\n",srv->weight);
+ printf("port=%d\n",srv->port);
+ printf("target=%s\n",srv->target);
+#endif
+ }
+
+ /* Now we have an array of all the srv records. */
+
+ /* Order by priority */
+ qsort(*list,srvcount,sizeof(struct srventry),priosort);
+
+ /* For each priority, move the zero-weighted items first. */
+ for(i=0;i<srvcount;i++)
+ {
+ int j;
+
+ for(j=i;j<srvcount && (*list)[i].priority==(*list)[j].priority;j++)
+ {
+ if((*list)[j].weight==0)
+ {
+ /* Swap j with i */
+ if(j!=i)
+ {
+ struct srventry temp;
+
+ memcpy(&temp,&(*list)[j],sizeof(struct srventry));
+ memcpy(&(*list)[j],&(*list)[i],sizeof(struct srventry));
+ memcpy(&(*list)[i],&temp,sizeof(struct srventry));
+ }
+
+ break;
+ }
+ }
+ }
+
+ /* Run the RFC-2782 weighting algorithm. We don't need very
+ high quality randomness for this, so regular libc srand/rand
+ is sufficient. */
+ srand(time(NULL)*getpid());
+
+ for(i=0;i<srvcount;i++)
+ {
+ int j;
+ float prio_count=0,chose;
+
+ for(j=i;j<srvcount && (*list)[i].priority==(*list)[j].priority;j++)
+ {
+ prio_count+=(*list)[j].weight;
+ (*list)[j].run_count=prio_count;
+ }
+
+ chose=prio_count*rand()/RAND_MAX;
+
+ for(j=i;j<srvcount && (*list)[i].priority==(*list)[j].priority;j++)
+ {
+ if(chose<=(*list)[j].run_count)
+ {
+ /* Swap j with i */
+ if(j!=i)
+ {
+ struct srventry temp;
+
+ memcpy(&temp,&(*list)[j],sizeof(struct srventry));
+ memcpy(&(*list)[j],&(*list)[i],sizeof(struct srventry));
+ memcpy(&(*list)[i],&temp,sizeof(struct srventry));
+ }
+ break;
+ }
+ }
+ }
+ }
+
+ return srvcount;
+
+ noanswer:
+ xfree(*list);
+ *list=NULL;
+ return 0;
+
+ fail:
+ xfree(*list);
+ *list=NULL;
+ return -1;
+}
+
+#ifdef TEST
+int
+main(int argc,char *argv[])
+{
+ struct srventry *srv;
+ int rc,i;
+
+ rc=getsrv("_hkp._tcp.wwwkeys.pgp.net",&srv);
+ printf("Count=%d\n\n",rc);
+ for(i=0;i<rc;i++)
+ {
+ printf("priority=%hu\n",srv[i].priority);
+ printf("weight=%hu\n",srv[i].weight);
+ printf("port=%hu\n",srv[i].port);
+ printf("target=%s\n",srv[i].target);
+ printf("\n");
+ }
+
+ xfree(srv);
+
+ return 0;
+}
+#endif /* TEST */
+
+/*
+Local Variables:
+compile-command: "cc -DTEST -I.. -I../include -Wall -g -o srv srv.c -lresolv libutil.a"
+End:
+*/