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author | Werner Koch <wk@gnupg.org> | 2006-08-16 12:47:53 +0200 |
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committer | Werner Koch <wk@gnupg.org> | 2006-08-16 12:47:53 +0200 |
commit | b744f963d7061ce55d2eed65b281298476e54fb7 (patch) | |
tree | 6e8ccb3c39a45c16b4ca6cdb2273eb3b8bc2a888 /common/srv.c | |
parent | Changed HTTP API. (diff) | |
download | gnupg2-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.c | 257 |
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: +*/ |