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mdig: --dns-make-query,--dns-parse-query

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bol-van
2024-10-26 15:19:20 +03:00
parent d59c77a899
commit 6be62d775b
14 changed files with 168 additions and 13 deletions
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157
mdig/mdig.c
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@@ -319,15 +319,135 @@ static int run_threads(void)
return thread ? 0 : 12;
}
// slightly patched musl code
size_t dns_mk_query_blob(uint8_t op, const char *dname, uint8_t class, uint8_t type, uint8_t *buf, size_t buflen)
{
int i, j;
uint16_t id;
struct timespec ts;
size_t l = strnlen(dname, 255);
size_t n;
if (l && dname[l-1]=='.') l--;
if (l && dname[l-1]=='.') return 0;
n = 17+l+!!l;
if (l>253 || buflen<n || op>15u) return 0;
/* Construct query template - ID will be filled later */
memset(buf, 0, n);
buf[2] = (op<<3) | 1;
buf[5] = 1;
memcpy((char *)buf+13, dname, l);
for (i=13; buf[i]; i=j+1)
{
for (j=i; buf[j] && buf[j] != '.'; j++);
if (j-i-1u > 62u) return 0;
buf[i-1] = j-i;
}
buf[i+1] = type;
buf[i+3] = class;
/* Make a reasonably unpredictable id */
clock_gettime(CLOCK_REALTIME, &ts);
id = (uint16_t)ts.tv_nsec + (uint16_t)(ts.tv_nsec>>16);
buf[0] = id>>8;
buf[1] = id;
return n;
}
int dns_make_query(const char *dom, char family)
{
uint8_t q[280];
size_t l = dns_mk_query_blob(0, dom, 1, family == FAMILY6 ? 28 : 1, q, sizeof(q));
if (!l)
{
fprintf(stderr, "could not make DNS query\n");
return 1;
}
if (fwrite(q,l,1,stdout)!=1)
{
fprintf(stderr, "could not write DNS query blob to stdout\n");
return 10;
}
return 0;
}
bool dns_parse_print(const uint8_t *a, size_t len)
{
// check of minimum header length and response flag
uint16_t k, dlen, qcount = a[4]<<8 | a[5], acount = a[6]<<8 | a[7];
char s_ip[40];
if (len<12 || !(a[2]&0x80)) return false;
a+=12; len-=12;
for(k=0;k<qcount;k++)
{
while (len && *a)
{
if ((*a+1)>len) return false;
// skip to next label
len -= *a+1; a += *a+1;
}
if (len<5) return false;
// skip zero length label, type, class
a+=5; len-=5;
}
for(k=0;k<acount;k++)
{
// 11 higher bits indicate pointer
if (len<12 || (*a & 0xC0)!=0xC0) return false;
dlen = a[10]<<8 | a[11];
if (len<(dlen+12)) return false;
if (a[4]==0 && a[5]==1 && a[2]==0) // IN class and higher byte of type = 0
{
switch(a[3])
{
case 1: // A
if (dlen!=4) break;
if (inet_ntop(AF_INET, a+12, s_ip, sizeof(s_ip)))
printf("%s\n", s_ip);
break;
case 28: // AAAA
if (dlen!=16) break;
if (inet_ntop(AF_INET6, a+12, s_ip, sizeof(s_ip)))
printf("%s\n", s_ip);
break;
}
}
len -= 12+dlen; a += 12+dlen;
}
return true;
}
int dns_parse_query()
{
uint8_t a[1500];
size_t l;
l = fread(a,1,sizeof(a),stdin);
if (!l || !feof(stdin))
{
fprintf(stderr, "could not read DNS reply blob from stdin\n");
return 10;
}
if (!dns_parse_print(a,l))
{
fprintf(stderr, "could not parse DNS reply blob\n");
return 11;
}
return 0;
}
static void exithelp(void)
{
printf(
" --threads=<threads_number>\n"
" --family=<4|6|46>\t; ipv4, ipv6, ipv4+ipv6\n"
" --verbose\t\t; print query progress to stderr\n"
" --stats=N\t\t; print resolve stats to stderr every N domains\n"
" --log-resolved=<file>\t; log successfully resolved domains to a file\n"
" --log-failed=<file>\t; log failed domains to a file\n"
" --family=<4|6|46>\t\t; ipv4, ipv6, ipv4+ipv6\n"
" --verbose\t\t\t; print query progress to stderr\n"
" --stats=N\t\t\t; print resolve stats to stderr every N domains\n"
" --log-resolved=<file>\t\t; log successfully resolved domains to a file\n"
" --log-failed=<file>\t\t; log failed domains to a file\n"
" --dns-make-query=<domain>\t; output to stdout binary blob with DNS query. use --family to specify ip version.\n"
" --dns-parse-query\t\t; read from stdin binary DNS answer blob and parse it to ipv4/ipv6 addresses\n"
);
exit(1);
}
@@ -335,20 +455,23 @@ int main(int argc, char **argv)
{
int r, v, option_index = 0;
char fn1[256],fn2[256];
char dom[256];
static const struct option long_options[] = {
{"help",no_argument,0,0}, // optidx=0
{"threads",required_argument,0,0}, // optidx=1
{"family",required_argument,0,0}, // optidx=2
{"verbose",no_argument,0,0}, // optidx=3
{"stats",required_argument,0,0}, // optidx=4
{"log-resolved",required_argument,0,0}, // optidx=5
{"log-failed",required_argument,0,0}, // optidx=6
{"help",no_argument,0,0}, // optidx=0
{"threads",required_argument,0,0}, // optidx=1
{"family",required_argument,0,0}, // optidx=2
{"verbose",no_argument,0,0}, // optidx=3
{"stats",required_argument,0,0}, // optidx=4
{"log-resolved",required_argument,0,0}, // optidx=5
{"log-failed",required_argument,0,0}, // optidx=6
{"dns-make-query",required_argument,0,0}, // optidx=7
{"dns-parse-query",no_argument,0,0}, // optidx=8
{NULL,0,NULL,0}
};
memset(&glob, 0, sizeof(glob));
*fn1 = *fn2 = 0;
*fn1 = *fn2 = *dom = 0;
glob.family = FAMILY4;
glob.threads = 1;
while ((v = getopt_long_only(argc, argv, "", long_options, &option_index)) != -1)
@@ -394,6 +517,12 @@ int main(int argc, char **argv)
strncpy(fn2,optarg,sizeof(fn2));
fn2[sizeof(fn2)-1] = 0;
break;
case 7: /* dns-make-query */
strncpy(dom,optarg,sizeof(dom));
dom[sizeof(dom)-1] = 0;
break;
case 8: /* dns-parse-query */
return dns_parse_query();
}
}
@@ -406,6 +535,8 @@ int main(int argc, char **argv)
}
#endif
if (*dom) return dns_make_query(dom, glob.family);
if (*fn1)
{
glob.F_log_resolved = fopen(fn1,"wt");