toys/net/host.c - platform/external/toybox - Git at Google

 /* host.c - DNS lookup utility
  *
  * Copyright 2014 Rich Felker <dalias@aerifal.cx>
  *
  * No standard, but there's a version in bind9
  * See https://www.ietf.org/rfc/rfc1035.txt
  * See https://www.ietf.org/rfc/rfc3596.txt

 USE_HOST(NEWTOY(host, "<1>2avt:", TOYFLAG_USR|TOYFLAG_BIN))

 config HOST
   bool "host"
   default y
   help
     usage: host [-v] [-t TYPE] NAME [SERVER]

     Look up DNS records for NAME, either domain name or IPv4/IPv6 address to
     reverse lookup, from SERVER or default DNS server(s).

     -a	All records
     -t TYPE	Record TYPE (number or ANY A AAAA CNAME MX NS PTR SOA SRV TXT)
     -v	Verbose
 */

 #define FOR_host
 #include "toys.h"
 #include <resolv.h>

 GLOBALS(
   char *t;

   char **nsname;
   unsigned nslen;
 )

 static const struct rrt {
   char *name, *msg;
   int type;
 } rrt[] = { { "A", "has address", 1 }, { "NS", "name server", 2 },
   { "CNAME", "is a nickname for", 5 }, { "SOA", "start of authority", 6 },
   { "PTR", "domain name pointer", 12 }, { "HINFO", "host information", 13 },
   { "MX", "mail is handled", 15 }, { "TXT", "descriptive text", 16 },
   { "AAAA", "has address", 28 }, { "SRV", "mail is handled", 33 }
 };

 int xdn_expand(char *packet, char *endpkt, char *comp, char *expand, int elen)
 {
   int i = dn_expand(packet, endpkt, comp, expand, elen);

   if (i<1) error_exit("bad dn_expand");

   return i;
 }

 // Fetch "nameserve" lines from /etc/resolv.conf. Ignores 'options' lines
 static void get_nsname(char **pline, long len)
 {
   char *line, *p;

   if (!len) return;
   line = *pline;
   if (strstart(&line, "nameserver") && isspace(*line)) {
     while (isspace(*line)) line++;
     for (p = line; *p && !isspace(*p) && *p!='#'; p++);
     if (p == line) return;
     *p = 0;
     if (!(TT.nslen&8))
       TT.nsname = xrealloc(TT.nsname, (TT.nslen+8)*sizeof(void *));
     TT.nsname[TT.nslen++] = xstrdup(line);
   }
 }

 void host_main(void)
 {
   int verbose = FLAG(a)||FLAG(v), type, abuf_len = 65536, //Largest TCP response
       i, j, sec, rcode, qlen, alen QUIET, pllen = 0, t2len = 2048;
   unsigned count, ttl;
   char *abuf = xmalloc(abuf_len), *name = *toys.optargs, *p, *ss,
        *t2 = toybuf+t2len;
   struct addrinfo *ai;

   // What kind of query are we doing?
   if (!TT.t && FLAG(a)) TT.t = "255";
   if (!getaddrinfo(name, 0,&(struct addrinfo){.ai_flags=AI_NUMERICHOST}, &ai)) {
     name = toybuf;
     if (ai->ai_family == AF_INET) {
       p = (void *)&((struct sockaddr_in *)ai->ai_addr)->sin_addr;
       sprintf(name, "%d.%d.%d.%d.in-addr.arpa", p[3], p[2], p[1], p[0]);
     } else if (ai->ai_family == AF_INET6) {
       p = (void *)&((struct sockaddr_in6 *)ai->ai_addr)->sin6_addr;
       for (j = 0, i = 15; i>=0; i--)
         j += sprintf(name+j, "%x.%x.", p[i]&15, p[i]>>4);
       strcpy(name+j, "ip6.arpa");
     }
     if (!TT.t) TT.t = "12";
   } else if (!TT.t) TT.t = "1";

   // Prepare query packet of appropriate type
   if (TT.t[0]-'0'<10) type = atoi(TT.t); // TODO
   else if (!strcasecmp(TT.t, "any") || !strcmp(TT.t, "*")) type = 255;
   else {
     for (i = 0; i<ARRAY_LEN(rrt); i++) if (!strcasecmp(TT.t, rrt[i].name)) {
       type = rrt[i].type;
       break;
     }
     if (i == ARRAY_LEN(rrt)) error_exit("bad -t: %s", TT.t);
   }
   qlen = res_mkquery(0, name, 1, type, 0, 0, 0, t2, 280); //t2len);
   if (qlen<0) error_exit("bad NAME: %s", name);

   // Grab nameservers
   if (toys.optargs[1]) TT.nsname = toys.optargs+1;
   else do_lines(xopen("/etc/resolv.conf", O_RDONLY), '\n', get_nsname);
   if (!TT.nsname) error_exit("No nameservers");

   // Send one query packet to each server until we receive response
   while (*TT.nsname) {
     if (verbose) printf("Using domain server %s:\n", *TT.nsname);
     ai = xgetaddrinfo(*TT.nsname, "53", 0, SOCK_DGRAM, 0, 0);
     i = xsocket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
     xconnect(i, ai->ai_addr, ai->ai_addrlen);
     setsockopt(i, SOL_SOCKET, SO_RCVTIMEO, &(struct timeval){ .tv_sec = 5 },
       sizeof(struct timeval));
     send(i, t2, qlen, 0);
     if (16 < (alen = recv(i, abuf, abuf_len, 0))) break;
     if (!*++TT.nsname) error_exit("Host not found.");
     close(i);
   }

   // Did it error?
   rcode = abuf[3]&7;
   if (verbose) {
     printf("rcode = %d, ancount = %d\n", rcode, (int)peek_be(abuf+6, 2));
     if (!(abuf[2]&4)) puts("The following answer is not authoritative:");
   }
   if (rcode) error_exit("Host not found: %s",
     (char *[]){ "Format error", "Server failure",
     "Non-existant domain", "Not implemented", "Refused", ""}[rcode-1]);

   // Print the result
   p = abuf + 12;
   qlen = 0;
   for (sec = 0; sec<(2<<verbose); sec++) {
     count = peek_be(abuf+4+2*sec, 2);
     if (verbose && count>0 && sec>1)
       puts(sec==2 ? "For authoritative answers, see:"
         : "Additional information:");

     for (; count--; p += pllen) {
       p += xdn_expand(abuf, abuf+alen, p, toybuf, 4096-t2len);
       if (alen-(p-abuf)<10) error_exit("tilt");
       type = peek_be(p, 2);
       p += 4;
       if (!sec) continue;
       ttl = peek_be(p, 4);
       p += 4;
       pllen = peek_be(p, 2);
       p += 2;
       if ((p-abuf)+pllen>alen) error_exit("tilt");
       if (type==1 || type == 28)
         inet_ntop(type==1 ? AF_INET : AF_INET6, p, t2, t2len);
       else if (type==2 || type==5) xdn_expand(abuf, abuf+alen, p, t2, t2len);
       else if (type==13 || type==16)
         sprintf(t2, "\"%.*s\"", minof(pllen, t2len), p);
       else if (type==6) {
         ss = p+xdn_expand(abuf, abuf+alen, p, t2, t2len-1);
         j = strlen(t2);
         t2[j++] = ' ';
         ss += xdn_expand(abuf, abuf+alen, ss, t2+j, t2len-j);
         j += strlen(t2+j);
         snprintf(t2+j, t2len-j, "(\n\t\t%u\t;serial (version)\n\t\t%u\t"
           ";refresh period\n\t\t%u\t;retry interval\n\t\t%u\t;expire time\n"
           "\t\t%u\t;default ttl\n\t\t)", (unsigned)peek_be(ss, 4),
           (unsigned)peek_be(ss+4, 4), (unsigned)peek_be(ss+8, 4),
           (unsigned)peek_be(ss+12, 4), (unsigned)peek_be(ss+16, 4));
       } else if (type==15) {
         j = peek_be(p, 2);
         j = sprintf(t2, verbose ? "%d " : "(pri=%d) by ", j);
         xdn_expand(abuf, abuf+alen, p+2, t2+j, t2len-j);
       } else if (type==33) {
         j = sprintf(t2, "%u %u %u ", (int)peek_be(p, 2), (int)peek_be(p+2, 2),
           (int)peek_be(p+4, 2));
         xdn_expand(abuf, abuf+alen, p+6, t2+j, t2len-j);
       } else {
         printf("%s unsupported RR type %u\n", toybuf, type);
         continue;
       }
       for (i = 0; rrt[i].type != type; i++);
       if (verbose) printf("%s\t%u\tIN %s\t%s\n", toybuf, ttl, rrt[i].name, t2);
       else printf("%s %s %s\n", toybuf, rrt[i].msg, t2);
       qlen++;
     }
   }
   if (TT.t && !qlen) printf("%s has no %s record\n", *toys.optargs, TT.t);

   if (CFG_TOYBOX_FREE) free(abuf);
   toys.exitval = rcode;
 }
	/* host.c - DNS lookup utility
	*
	* Copyright 2014 Rich Felker <dalias@aerifal.cx>
	*
	* No standard, but there's a version in bind9
	* See https://www.ietf.org/rfc/rfc1035.txt
	* See https://www.ietf.org/rfc/rfc3596.txt

	USE_HOST(NEWTOY(host, "<1>2avt:", TOYFLAG_USR\|TOYFLAG_BIN))

	config HOST
	bool "host"
	default y
	help
	usage: host [-v] [-t TYPE] NAME [SERVER]

	Look up DNS records for NAME, either domain name or IPv4/IPv6 address to
	reverse lookup, from SERVER or default DNS server(s).

	-a All records
	-t TYPE Record TYPE (number or ANY A AAAA CNAME MX NS PTR SOA SRV TXT)
	-v Verbose
	*/

	#define FOR_host
	#include "toys.h"
	#include <resolv.h>

	GLOBALS(
	char *t;

	char **nsname;
	unsigned nslen;
	)

	static const struct rrt {
	char name, msg;
	int type;
	} rrt[] = { { "A", "has address", 1 }, { "NS", "name server", 2 },
	{ "CNAME", "is a nickname for", 5 }, { "SOA", "start of authority", 6 },
	{ "PTR", "domain name pointer", 12 }, { "HINFO", "host information", 13 },
	{ "MX", "mail is handled", 15 }, { "TXT", "descriptive text", 16 },
	{ "AAAA", "has address", 28 }, { "SRV", "mail is handled", 33 }
	};

	int xdn_expand(char packet, char endpkt, char comp, char expand, int elen)
	{
	int i = dn_expand(packet, endpkt, comp, expand, elen);

	if (i<1) error_exit("bad dn_expand");

	return i;
	}

	// Fetch "nameserve" lines from /etc/resolv.conf. Ignores 'options' lines
	static void get_nsname(char **pline, long len)
	{
	char line, p;

	if (!len) return;
	line = *pline;
	if (strstart(&line, "nameserver") && isspace(*line)) {
	while (isspace(*line)) line++;
	for (p = line; p && !isspace(p) && *p!='#'; p++);
	if (p == line) return;
	*p = 0;
	if (!(TT.nslen&8))
	TT.nsname = xrealloc(TT.nsname, (TT.nslen+8)sizeof(void ));
	TT.nsname[TT.nslen++] = xstrdup(line);
	}
	}

	void host_main(void)
	{
	int verbose = FLAG(a)\|\|FLAG(v), type, abuf_len = 65536, //Largest TCP response
	i, j, sec, rcode, qlen, alen QUIET, pllen = 0, t2len = 2048;
	unsigned count, ttl;
	char abuf = xmalloc(abuf_len), name = toys.optargs, p, *ss,
	*t2 = toybuf+t2len;
	struct addrinfo *ai;

	// What kind of query are we doing?
	if (!TT.t && FLAG(a)) TT.t = "255";
	if (!getaddrinfo(name, 0,&(struct addrinfo){.ai_flags=AI_NUMERICHOST}, &ai)) {
	name = toybuf;
	if (ai->ai_family == AF_INET) {
	p = (void )&((struct sockaddr_in )ai->ai_addr)->sin_addr;
	sprintf(name, "%d.%d.%d.%d.in-addr.arpa", p[3], p[2], p[1], p[0]);
	} else if (ai->ai_family == AF_INET6) {
	p = (void )&((struct sockaddr_in6 )ai->ai_addr)->sin6_addr;
	for (j = 0, i = 15; i>=0; i--)
	j += sprintf(name+j, "%x.%x.", p[i]&15, p[i]>>4);
	strcpy(name+j, "ip6.arpa");
	}
	if (!TT.t) TT.t = "12";
	} else if (!TT.t) TT.t = "1";

	// Prepare query packet of appropriate type
	if (TT.t[0]-'0'<10) type = atoi(TT.t); // TODO
	else if (!strcasecmp(TT.t, "any") \|\| !strcmp(TT.t, "*")) type = 255;
	else {
	for (i = 0; i<ARRAY_LEN(rrt); i++) if (!strcasecmp(TT.t, rrt[i].name)) {
	type = rrt[i].type;
	break;
	}
	if (i == ARRAY_LEN(rrt)) error_exit("bad -t: %s", TT.t);
	}
	qlen = res_mkquery(0, name, 1, type, 0, 0, 0, t2, 280); //t2len);
	if (qlen<0) error_exit("bad NAME: %s", name);

	// Grab nameservers
	if (toys.optargs[1]) TT.nsname = toys.optargs+1;
	else do_lines(xopen("/etc/resolv.conf", O_RDONLY), '\n', get_nsname);
	if (!TT.nsname) error_exit("No nameservers");

	// Send one query packet to each server until we receive response
	while (*TT.nsname) {
	if (verbose) printf("Using domain server %s:\n", *TT.nsname);
	ai = xgetaddrinfo(*TT.nsname, "53", 0, SOCK_DGRAM, 0, 0);
	i = xsocket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
	xconnect(i, ai->ai_addr, ai->ai_addrlen);
	setsockopt(i, SOL_SOCKET, SO_RCVTIMEO, &(struct timeval){ .tv_sec = 5 },
	sizeof(struct timeval));
	send(i, t2, qlen, 0);
	if (16 < (alen = recv(i, abuf, abuf_len, 0))) break;
	if (!*++TT.nsname) error_exit("Host not found.");
	close(i);
	}

	// Did it error?
	rcode = abuf[3]&7;
	if (verbose) {
	printf("rcode = %d, ancount = %d\n", rcode, (int)peek_be(abuf+6, 2));
	if (!(abuf[2]&4)) puts("The following answer is not authoritative:");
	}
	if (rcode) error_exit("Host not found: %s",
	(char *[]){ "Format error", "Server failure",
	"Non-existant domain", "Not implemented", "Refused", ""}[rcode-1]);

	// Print the result
	p = abuf + 12;
	qlen = 0;
	for (sec = 0; sec<(2<<verbose); sec++) {
	count = peek_be(abuf+4+2*sec, 2);
	if (verbose && count>0 && sec>1)
	puts(sec==2 ? "For authoritative answers, see:"
	: "Additional information:");

	for (; count--; p += pllen) {
	p += xdn_expand(abuf, abuf+alen, p, toybuf, 4096-t2len);
	if (alen-(p-abuf)<10) error_exit("tilt");
	type = peek_be(p, 2);
	p += 4;
	if (!sec) continue;
	ttl = peek_be(p, 4);
	p += 4;
	pllen = peek_be(p, 2);
	p += 2;
	if ((p-abuf)+pllen>alen) error_exit("tilt");
	if (type==1 \|\| type == 28)
	inet_ntop(type==1 ? AF_INET : AF_INET6, p, t2, t2len);
	else if (type==2 \|\| type==5) xdn_expand(abuf, abuf+alen, p, t2, t2len);
	else if (type==13 \|\| type==16)
	sprintf(t2, "\"%.*s\"", minof(pllen, t2len), p);
	else if (type==6) {
	ss = p+xdn_expand(abuf, abuf+alen, p, t2, t2len-1);
	j = strlen(t2);
	t2[j++] = ' ';
	ss += xdn_expand(abuf, abuf+alen, ss, t2+j, t2len-j);
	j += strlen(t2+j);
	snprintf(t2+j, t2len-j, "(\n\t\t%u\t;serial (version)\n\t\t%u\t"
	";refresh period\n\t\t%u\t;retry interval\n\t\t%u\t;expire time\n"
	"\t\t%u\t;default ttl\n\t\t)", (unsigned)peek_be(ss, 4),
	(unsigned)peek_be(ss+4, 4), (unsigned)peek_be(ss+8, 4),
	(unsigned)peek_be(ss+12, 4), (unsigned)peek_be(ss+16, 4));
	} else if (type==15) {
	j = peek_be(p, 2);
	j = sprintf(t2, verbose ? "%d " : "(pri=%d) by ", j);
	xdn_expand(abuf, abuf+alen, p+2, t2+j, t2len-j);
	} else if (type==33) {
	j = sprintf(t2, "%u %u %u ", (int)peek_be(p, 2), (int)peek_be(p+2, 2),
	(int)peek_be(p+4, 2));
	xdn_expand(abuf, abuf+alen, p+6, t2+j, t2len-j);
	} else {
	printf("%s unsupported RR type %u\n", toybuf, type);
	continue;
	}
	for (i = 0; rrt[i].type != type; i++);
	if (verbose) printf("%s\t%u\tIN %s\t%s\n", toybuf, ttl, rrt[i].name, t2);
	else printf("%s %s %s\n", toybuf, rrt[i].msg, t2);
	qlen++;
	}
	}
	if (TT.t && !qlen) printf("%s has no %s record\n", *toys.optargs, TT.t);

	if (CFG_TOYBOX_FREE) free(abuf);
	toys.exitval = rcode;
	}