diff options
Diffstat (limited to 'mdk-stage1/dietlibc/libcruft/dnscruft2.c')
| -rw-r--r-- | mdk-stage1/dietlibc/libcruft/dnscruft2.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/mdk-stage1/dietlibc/libcruft/dnscruft2.c b/mdk-stage1/dietlibc/libcruft/dnscruft2.c new file mode 100644 index 000000000..b59207072 --- /dev/null +++ b/mdk-stage1/dietlibc/libcruft/dnscruft2.c @@ -0,0 +1,185 @@ +#include <string.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <netdb.h> +#include <stdlib.h> +#include <arpa/inet.h> +#include <sys/poll.h> +#include <unistd.h> +#include <errno.h> + +#include <stdio.h> + +extern int h_errno; + +static char dnspacket[]="\xfe\xfe\001\000\000\001\000\000\000\000\000\000"; + +extern void __dns_make_fd(); +extern int __dns_fd; + +extern int __dns_servers; +extern struct sockaddr __dns_server_ips[]; + +extern void __dns_readstartfiles(); + +extern int __dns_decodename(unsigned char *packet,int offset,unsigned char *dest,int maxlen); + +/* Oh boy, this interface sucks so badly, there are no words for it. + * Not one, not two, but _three_ error signalling methods! (*h_errnop + * nonzero? return value nonzero? *RESULT zero?) The glibc goons + * really outdid themselves with this one. */ +int __dns_gethostbyx_r(const char* name, struct hostent* result, + char *buf, size_t buflen, + struct hostent **RESULT, int *h_errnop, int lookfor) { + int names,ips; + unsigned char *cur; + unsigned char *max; + unsigned char packet[512]; + __dns_make_fd(); + + if (lookfor==1) { + result->h_aliases=(char**)(buf+8*4); + result->h_addrtype=AF_INET; + result->h_length=4; + result->h_addr_list=(char**)buf; + } else { + result->h_aliases=(char**)(buf+8*16); + result->h_addrtype=AF_INET6; + result->h_length=16; + result->h_addr_list=(char**)buf; + } + result->h_aliases[0]=0; + + cur=buf+16*sizeof(char*); + max=buf+buflen; + names=ips=0; + + memmove(packet,dnspacket,12); + *(unsigned short*)packet=rand(); + { + unsigned char* x; + const char* y,* tmp; + x=packet+12; y=name; + while (*y) { + while (*y=='.') ++y; + for (tmp=y; *tmp && *tmp!='.'; ++tmp) ; + *x=tmp-y; + if (!(tmp-y)) break; + ++x; + if (x>=packet+510-(tmp-y)) { *h_errnop=ERANGE; return 1; } + memmove(x,y,tmp-y); + x+=tmp-y; + if (!*tmp) { + *x=0; + break; + } + y=tmp; + } + *++x= 0; *++x= lookfor; /* A */ + *++x= 0; *++x= 1; /* IN */ + ++x; + { + int i; /* current server */ + int j; /* timeout count down */ + struct pollfd duh; + i=0; j=30; + __dns_readstartfiles(); + duh.fd=__dns_fd; + duh.events=POLLIN; + for (j=30; j>0; --j) { + sendto(__dns_fd,packet,x-packet,0,(struct sockaddr*)&(__dns_server_ips[i]),sizeof(struct sockaddr)); + if (++i > __dns_servers) i=0; + if (poll(&duh,1,1) == 1) { + /* read and parse answer */ + unsigned char inpkg[1500]; + /*int len=*/ read(__dns_fd,inpkg,1500); +#if 0 + { + int tft=open("duh",0); + read(tft,inpkg,1500); + close(tft); + } +#endif + /* header, question, answer, authority, additional */ + if (inpkg[0]!=packet[0] || inpkg[1]!=packet[1]) continue; /* wrong ID */ + if ((inpkg[2]&0xf9) != 0x81) continue; /* not answer */ + if ((inpkg[3]&0x0f) != 0) break; /* error */ + tmp=inpkg+12; + { + char name[257]; + unsigned short q=((unsigned short)inpkg[4]<<8)+inpkg[5]; + while (q>0) { + while (*tmp) tmp+=*tmp+1; + tmp+=5; + --q; + } + q=((unsigned short)inpkg[6]<<8)+inpkg[7]; + if (q<1) break; + while (q>0) { + int decofs=__dns_decodename(inpkg,tmp-(char*)inpkg,name,256); + if (decofs<0) break; + tmp=inpkg+decofs; + --q; + if (tmp[0]!=0 || tmp[1]!=lookfor || /* TYPE != A */ + tmp[2]!=0 || tmp[3]!=1) { /* CLASS != IN */ + if (tmp[1]==5) { /* CNAME */ + tmp+=10; + decofs=__dns_decodename(inpkg,tmp-(char*)inpkg,name,256); + if (decofs<0) break; + tmp=inpkg+decofs; + } else + break; + continue; + } + tmp+=10; /* skip type, class, TTL and length */ + { + int slen; + if (lookfor==1 || lookfor==28) /* A or AAAA*/ { + slen=strlen(name); + if (cur+slen+8+(lookfor==28?12:0)>=max) { *h_errnop=NO_RECOVERY; return 1; } + } else if (lookfor==12) /* PTR */ { + decofs=__dns_decodename(inpkg,tmp-(char*)inpkg,name,256); + if (decofs<0) break; + tmp=inpkg+decofs; + slen=strlen(name); + } else + slen=strlen(name); + strcpy(cur,name); + if (names==0) + result->h_name=cur; + else + result->h_aliases[names-1]=cur; + result->h_aliases[names]=0; + ++names; +/* cur+=slen+1; */ + cur+=(slen|3)+1; + result->h_addr_list[ips++] = cur; + if (lookfor==1) /* A */ { + *(int*)cur=*(int*)tmp; + cur+=4; + result->h_addr_list[ips]=0; + } else if (lookfor==28) /* AAAA */ { + { + int i; + for (i=0; i<16; ++i) cur[i]=tmp[i]; + } + cur+=16; + result->h_addr_list[ips]=0; + } + } +/* puts(name); */ + } + } +/* printf("%d answers\n",((unsigned short)inpkg[6]<<8)+inpkg[7]); + printf("ok\n");*/ + *h_errnop=0; + *RESULT=result; + return 0; + } +/*kaputt:*/ + } + } + } + return 1; +} |