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7b4aa6ffc

"Vladimir N. Oleynik"

2006-01-25

SUCCESS Duration: 25s

Subject

new applet. Thanks Roberto A. Foglietta

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Debian 14.2.0-19) 14.2.0

—

Build Log

(log yok)

Commit Diff GitHub →

AUTHORS +3 -0 examples/dnsd.conf +1 -0 include/applets.h +3 -0 include/usage.h +11 -0 networking/Config.in +6 -0 networking/Makefile.in +1 -0 networking/dnsd.c +469 -0

AUTHORS+3 -0

@@ -159,3 +159,6 @@ Tito Ragusa <[email protected]>

	Paul Fox <[email protected]>
	vi editing mode for ash, various other patches/fixes
+
+	Roberto A. Foglietta <[email protected]>
+	port: dnsd

examples/dnsd.conf+1 -0

@@ -0,0 +1 @@
+	thebox 192.168.1.5

include/applets.h+3 -0

@@ -164,6 +164,9 @@
	#ifdef CONFIG_DMESG
	APPLET(dmesg, dmesg_main, _BB_DIR_BIN, _BB_SUID_NEVER)
	#endif
+	#ifdef CONFIG_DNSD
+	APPLET(dnsd, dnsd_main, _BB_DIR_USR_SBIN, _BB_SUID_ALWAYS)
+	#endif
	#ifdef CONFIG_DOS2UNIX
	APPLET(dos2unix, dos2unix_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER)
	#endif

include/usage.h+11 -0

@@ -469,6 +469,17 @@
	"\t-n LEVEL\tSets console logging level\n" \
	"\t-s SIZE\t\tUse a buffer of size SIZE"

+	#define dnsd_trivial_usage \
+	"[-c config] [-t seconds] [-p port] [-i iface-ip] [-d]"
+	#define dnsd_full_usage \
+	"Small and static DNS server daemon\n\n" \
+	"Options:\n" \
+	"\t-c\t\tconfig filename\n" \
+	"\t-t\t\tTTL in seconds\n" \
+	"\t-p\t\tlistening port\n" \
+	"\t-i\t\tlistening iface ip (default all)\n" \
+	"\t-d\t\tdaemonize"
+
	#define dos2unix_trivial_usage \
	"[option] [FILE]"
	#define dos2unix_full_usage \

networking/Config.in+6 -0

@@ -18,6 +18,12 @@ config CONFIG_ARPING
	help
	Ping hosts by ARP packets

+	config CONFIG_DNSD
+	bool "dnsd"
+	default n
+	help
+	Small and static DNS server deamon.
+
	config CONFIG_ETHER_WAKE
	bool "ether-wake"
	default n

networking/Makefile.in+1 -0

@@ -12,6 +12,7 @@ srcdir=$(top_srcdir)/networking

	NETWORKING-y:=
	NETWORKING-$(CONFIG_ARPING) += arping.o
+	NETWORKING-$(CONFIG_DNSD) += dnsd.o
	NETWORKING-$(CONFIG_ETHER_WAKE) += ether-wake.o
	NETWORKING-$(CONFIG_FAKEIDENTD) += fakeidentd.o
	NETWORKING-$(CONFIG_FTPGET) += ftpgetput.o

networking/dnsd.c+469 -0

@@ -0,0 +1,469 @@
+	/*
+	* Mini DNS server implementation for busybox
+	*
+	* Copyright (C) 2005 Roberto A. Foglietta ([email protected])
+	* Copyright (C) 2005 Odd Arild Olsen (oao at fibula dot no)
+	* Copyright (C) 2003 Paul Sheer
+	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+	*
+	* Odd Arild Olsen started out with the sheerdns [1] of Paul Sheer and rewrote
+	* it into a shape which I believe is both easier to understand and maintain.
+	* I also reused the input buffer for output and removed services he did not
+	* need. [1] http://threading.2038bug.com/sheerdns/
+	*
+	* Some bugfix and minor changes was applied by Roberto A. Foglietta who made
+	* the first porting of oao' scdns to busybox also.
+	*/
+
+	#include <unistd.h>
+	#include <string.h>
+	#include <signal.h>
+	#include <arpa/inet.h>
+	#include <ctype.h>
+	#include "libbb.h"
+
+	static char *fileconf = "/etc/dnsd.conf";
+	#define LOCK_FILE "/var/run/dnsd.lock"
+	#define LOG_FILE "/var/log/dnsd.log"
+
+	#define MAX_HOST_LEN 16 // longest host name allowed is 15
+	#define IP_STRING_LEN 18 // .xxx.xxx.xxx.xxx\0
+
+	//must be strlen('.in-addr.arpa') larger than IP_STRING_LEN
+	static const int MAX_NAME_LEN = (IP_STRING_LEN + 13);
+
+	/* Cannot get bigger packets than 512 per RFC1035
+	In practice this can be set considerably smaller:
+	Length of response packet is header (12B) + 2type(4B) + 2class(4B) +
+	ttl(4B) + rlen(2B) + r (MAX_NAME_LEN =21B) +
+	2*querystring (2 MAX_NAME_LEN= 42B), all together 90 Byte
+	*/
+	static const int MAX_PACK_LEN = 512 + 1;
+
+	#define DEFAULT_TTL 30; // increase this when not testing?
+
+	static const int REQ_A = 1;
+	static const int REQ_PTR = 12;
+
+	struct dns_repl { // resource record, add 0 or 1 to accepted dns_msg in resp
+	uint16_t rlen;
+	uint8_t *r; // resource
+	uint16_t flags;
+	};
+
+	struct dns_head { // the message from client and first part of response mag
+	uint16_t id;
+	uint16_t flags;
+	uint16_t nquer; // accepts 0
+	uint16_t nansw; // 1 in response
+	uint16_t nauth; // 0
+	uint16_t nadd; // 0
+	};
+	struct dns_prop {
+	uint16_t type;
+	uint16_t class;
+	};
+	struct dns_entry { // element of known name, ip address and reversed ip address
+	struct dns_entry *next;
+	char ip[IP_STRING_LEN]; // dotted decimal IP
+	char rip[IP_STRING_LEN]; // length decimal reversed IP
+	char name[MAX_HOST_LEN];
+	};
+
+	static struct dns_entry *dnsentry = NULL;
+	static int daemonmode = 0;
+	static uint32_t ttl = DEFAULT_TTL;
+
+	/*
+	* Convert host name from C-string to dns length/string.
+	*/
+	static void
+	convname(char a, uint8_t q)
+	{
+	int i = (q[0] == '.')?0:1;
+	for(; i < MAX_HOST_LEN-1 && *q; i++, q++)
+	a[i] = tolower(*q);
+	a[0] = i - 1;
+	a[i] = 0;
+	}
+
+	/*
+	* Insert length of substrings insetad of dots
+	*/
+	static void
+	undot(uint8_t * rip)
+	{
+	int i=0, s=0;
+	while(rip[i]) i++;
+	for(--i; i >= 0; i--) {
+	if(rip[i] == '.') {
+	rip[i] = s;
+	s = 0;
+	} else s++;
+	}
+	}
+
+	/*
+	* Append message to log file
+	*/
+	static void
+	log_message(char filename, char message)
+	{
+	FILE *logfile;
+	if (!daemonmode)
+	return;
+	logfile = fopen(filename, "a");
+	if (!logfile)
+	return;
+	fprintf(logfile, "%s\n", message);
+	fclose(logfile);
+	}
+
+	/*
+	* Read one line of hostname/IP from file
+	* Returns 0 for each valid entry read, -1 at EOF
+	* Assumes all host names are lower case only
+	* Hostnames with more than one label is not handled correctly.
+	* Presently the dot is copied into name without
+	* converting to a length/string substring for that label.
+	*/
+
+	static int
+	getfileentry(FILE * fp, struct dns_entry *s, int verb)
+	{
+	unsigned int a,b,c,d;
+	char r, name;
+
+	restart:
+	if(!(r = bb_get_line_from_file(fp)))
+	return -1;
+	while(r == ' ' \|\| r == '\t') {
+	r++;
+	if(!r \|\| r == '#' \|\| *r == '\n')
+	goto restart; /* skipping empty/blank and commented lines */
+	}
+	name = r;
+	while(r != ' ' && r != '\t')
+	r++;
+	*r++ = 0;
+	if(sscanf(r,"%u.%u.%u.%u",&a,&b,&c,&d) != 4)
+	goto restart; /* skipping wrong lines */
+
+	sprintf(s->ip,"%u.%u.%u.%u",a,b,c,d);
+	sprintf(s->rip,".%u.%u.%u.%u",d,c,b,a);
+	undot((uint8_t*)s->rip);
+	convname(s->name,(uint8_t*)name);
+
+	if(verb)
+	fprintf(stderr,"\tname:%s, ip:%s\n",&(s->name[1]),s->ip);
+
+	return 0; /* warningkiller */
+	}
+
+	/*
+	* Read hostname/IP records from file
+	*/
+	static void
+	dnsentryinit(int verb)
+	{
+	FILE *fp;
+	struct dns_entry m, prev;
+	prev = dnsentry = NULL;
+
+	if(!(fp = fopen(fileconf, "r")))
+	bb_perror_msg_and_die("open %s",fileconf);
+
+	while (1) {
+	if(!(m = (struct dns_entry *)malloc(sizeof(struct dns_entry))))
+	bb_perror_msg_and_die("malloc dns_entry");
+
+	m->next = NULL;
+	if (getfileentry(fp, m, verb))
+	break;
+
+	if (prev == NULL)
+	dnsentry = m;
+	else
+	prev->next = m;
+	prev = m;
+	}
+	fclose(fp);
+	}
+
+
+	/*
+	* Set up UDP socket
+	*/
+	static int
+	listen_socket(char *iface_addr, int listen_port)
+	{
+	struct sockaddr_in a;
+	char msg[100];
+	int s;
+	int yes = 1;
+	if ((s = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
+	bb_perror_msg_and_die("socket() failed");
+	#ifdef SO_REUSEADDR
+	if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&yes, sizeof(yes)) < 0)
+	bb_perror_msg_and_die("setsockopt() failed");
+	#endif
+	memset(&a, 0, sizeof(a));
+	a.sin_port = htons(listen_port);
+	a.sin_family = AF_INET;
+	if (!inet_aton(iface_addr, &a.sin_addr))
+	bb_perror_msg_and_die("bad iface address");
+	if (bind(s, (struct sockaddr *)&a, sizeof(a)) < 0)
+	bb_perror_msg_and_die("bind() failed");
+	listen(s, 50);
+	sprintf(msg, "accepting UDP packets on addr:port %s:%d\n",
+	iface_addr, (int)listen_port);
+	log_message(LOG_FILE, msg);
+	return s;
+	}
+
+	/*
+	* Look query up in dns records and return answer if found
+	* qs is the query string, first byte the string length
+	*/
+	static int
+	table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
+	{
+	int i;
+	struct dns_entry *d=dnsentry;
+
+	do {
+	#ifdef DEBUG
+	char p,q;
+	q = (char *)&(qs[1]);
+	p = &(d->name[1]);
+	fprintf(stderr, "\ntest: %d <%s> <%s> %d", strlen(p), p, q, strlen(q));
+	#endif
+	if (type == REQ_A) { /* search by host name */
+	for(i = 1; i <= (int)(d->name[0]); i++)
+	if(tolower(qs[i]) != d->name[i])
+	continue;
+	#ifdef DEBUG
+	fprintf(stderr, " OK");
+	#endif
+	strcpy((char *)as, d->ip);
+	#ifdef DEBUG
+	fprintf(stderr, " %s ", as);
+	#endif
+	return 0;
+	}
+	else if (type == REQ_PTR) { /* search by IP-address */
+	if (!strncmp((char)&d->rip[1], (char)&qs[1], strlen(d->rip)-1)) {
+	strcpy((char *)as, d->name);
+	return 0;
+	}
+	}
+	} while ((d = d->next) != NULL);
+	return -1;
+	}
+
+
+	/*
+	* Decode message and generate answer
+	*/
+	#define eret(s) do { fprintf (stderr, "%s\n", s); return -1; } while (0)
+	static int
+	process_packet(uint8_t * buf)
+	{
+	struct dns_head *head;
+	struct dns_prop *qprop;
+	struct dns_repl outr;
+	void next, from, *answb;
+
+	uint8_t answstr[MAX_NAME_LEN + 1];
+	int lookup_result, type, len, packet_len;
+	uint16_t flags;
+
+	answstr[0] = '\0';
+
+	head = (struct dns_head *)buf;
+	if (head->nquer == 0)
+	eret("no queries");
+
+	if ((head->flags & 0x8000))
+	eret("ignoring response packet");
+
+	from = (void *)&head[1]; // start of query string
+	next = answb = from + strlen((char *)&head[1]) + 1 + sizeof(struct dns_prop); // where to append answer block
+
+	outr.rlen = 0; // may change later
+	outr.r = NULL;
+	outr.flags = 0;
+
+	qprop = (struct dns_prop *)(answb - 4);
+	type = ntohs(qprop->type);
+
+	// only let REQ_A and REQ_PTR pass
+	if (!(type == REQ_A \|\| type == REQ_PTR)) {
+	goto empty_packet; /* we can't handle the query type */
+	}
+
+	if (ntohs(qprop->class) != 1 /* class INET */ ) {
+	outr.flags = 4; /* not supported */
+	goto empty_packet;
+	}
+	/* we only support standard queries */
+
+	if ((ntohs(head->flags) & 0x7800) != 0)
+	goto empty_packet;
+
+	// We have a standard query
+
+	log_message(LOG_FILE, (char *)head);
+	lookup_result = table_lookup(type, answstr, (uint8_t*)(&head[1]));
+	if (lookup_result != 0) {
+	outr.flags = 3 \| 0x0400; //name do not exist and auth
+	goto empty_packet;
+	}
+	if (type == REQ_A) { // return an address
+	struct in_addr a;
+	if (!inet_aton((char*)answstr, &a)) {//dotted dec to long conv
+	outr.flags = 1; /* Frmt err */
+	goto empty_packet;
+	}
+	memcpy(answstr, &a.s_addr, 4); // save before a disappears
+	outr.rlen = 4; // uint32_t IP
+	}
+	else
+	outr.rlen = strlen((char *)answstr) + 1; // a host name
+	outr.r = answstr; // 32 bit ip or a host name
+	outr.flags \|= 0x0400; /* authority-bit */
+	// we have an answer
+	head->nansw = htons(1);
+
+	// copy query block to answer block
+	len = answb - from;
+	memcpy(answb, from, len);
+	next += len;
+
+	// and append answer rr
+	(uint32_t ) next = htonl(ttl);
+	next += 4;
+	(uint16_t ) next = htons(outr.rlen);
+	next += 2;
+	memcpy(next, (void *)answstr, outr.rlen);
+	next += outr.rlen;
+
+	empty_packet:
+
+	flags = ntohs(head->flags);
+	// clear rcode and RA, set responsebit and our new flags
+	flags \|= (outr.flags & 0xff80) \| 0x8000;
+	head->flags = htons(flags);
+	head->nauth = head->nadd = htons(0);
+	head->nquer = htons(1);
+
+	packet_len = next - (void *)buf;
+	return packet_len;
+	}
+
+	/*
+	* Exit on signal
+	*/
+	static void
+	interrupt(int x)
+	{
+	unlink(LOCK_FILE);
+	write(2, "interrupt exiting\n", 18);
+	exit(2);
+	}
+
+	#define is_daemon() (flags&16)
+	#define is_verbose() (flags&32)
+	//#define DEBUG 1
+
+	int dnsd_main(int argc, char **argv)
+	{
+	int i, udps;
+	uint16_t port = 53;
+	uint8_t buf[MAX_PACK_LEN];
+	unsigned long flags = 0;
+	char *listen_interface = "0.0.0.0";
+	char sttl=NULL, sport=NULL;
+
+	if(argc > 1)
+	flags = bb_getopt_ulflags(argc, argv, "i:c:t:p:dv", &listen_interface, &fileconf, &sttl, &sport);
+	if(sttl)
+	if(!(ttl = atol(sttl)))
+	bb_show_usage();
+	if(sport)
+	if(!(port = atol(sport)))
+	bb_show_usage();
+
+	if(is_verbose()) {
+	fprintf(stderr,"listen_interface: %s\n", listen_interface);
+	fprintf(stderr,"ttl: %d, port: %d\n", ttl, port);
+	fprintf(stderr,"fileconf: %s\n", fileconf);
+	}
+
+	if(is_daemon())
+	#if defined(__uClinux__)
+	/* reexec for vfork() do continue parent */
+	vfork_daemon_rexec(1, 0, argc, argv, "-d");
+	#else /* uClinux */
+	if (daemon(1, 0) < 0) {
+	bb_perror_msg_and_die("daemon");
+	}
+	#endif /* uClinuvx */
+
+	dnsentryinit(is_verbose());
+
+	signal(SIGINT, interrupt);
+	signal(SIGPIPE, SIG_IGN);
+	signal(SIGHUP, SIG_IGN);
+	#ifdef SIGTSTP
+	signal(SIGTSTP, SIG_IGN);
+	#endif
+	#ifdef SIGURG
+	signal(SIGURG, SIG_IGN);
+	#endif
+
+	udps = listen_socket(listen_interface, port);
+	if (udps < 0)
+	exit(1);
+
+	while (1) {
+	fd_set fdset;
+	int r;
+
+	FD_ZERO(&fdset);
+	FD_SET(udps, &fdset);
+	// Block until a message arrives
+	if((r = select(udps + 1, &fdset, NULL, NULL, NULL)) < 0)
+	bb_perror_msg_and_die("select error");
+	else
+	if(r == 0)
+	bb_perror_msg_and_die("select spurious return");
+
+	/* Can this test ever be false? */
+	if (FD_ISSET(udps, &fdset)) {
+	struct sockaddr_in from;
+	int fromlen = sizeof(from);
+	r = recvfrom(udps, buf, sizeof(buf), 0,
+	(struct sockaddr *)&from,
+	(void *)&fromlen);
+	if(is_verbose())
+	fprintf(stderr, "\n--- Got UDP ");
+	log_message(LOG_FILE, "\n--- Got UDP ");
+
+	if (r < 12 \|\| r > 512) {
+	bb_error_msg("invalid packet size");
+	continue;
+	}
+	if (r > 0) {
+	r = process_packet(buf);
+	if (r > 0)
+	sendto(udps, buf,
+	r, 0, (struct sockaddr *)&from,
+	fromlen);
+	}
+	} // end if
+	} // end while
+	return 0;
+	}
+
+