+/* vi: set sw=4 ts=4: */
/*
* Mini DNS server implementation for busybox
*
* Copyright (C) 2005 Roberto A. Foglietta (me@roberto.foglietta.name)
* 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
* the first porting of oao' scdns to busybox also.
*/
-#include <unistd.h>
-#include <string.h>
-#include <signal.h>
-#include <arpa/inet.h>
-#include <sys/socket.h>
-#include <ctype.h>
-#include "libbb.h"
+#include "busybox.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 matct getopt32 call
+#define OPT_daemon (option_mask32 & 0x10)
+#define OPT_verbose (option_mask32 & 0x20)
+
+//#define DEBUG 1
+
+enum {
+ MAX_HOST_LEN = 16, // longest host name allowed is 15
+ 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);
+ MAX_NAME_LEN = (IP_STRING_LEN + 13),
/* Cannot get bigger packets than 512 per RFC1035
In practice this can be set considerably smaller:
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;
+ MAX_PACK_LEN = 512 + 1,
-#define DEFAULT_TTL 30; // increase this when not testing?
+ DEFAULT_TTL = 30, // increase this when not testing?
-static const int REQ_A = 1;
-static const int REQ_PTR = 12;
+ REQ_A = 1,
+ REQ_PTR = 12
+};
struct dns_repl { // resource record, add 0 or 1 to accepted dns_msg in resp
uint16_t rlen;
};
static struct dns_entry *dnsentry = NULL;
-static int daemonmode = 0;
+// FIXME! unused! :(
+static int daemonmode;
static uint32_t ttl = DEFAULT_TTL;
/*
* Convert host name from C-string to dns length/string.
*/
-static void
-convname(char *a, uint8_t *q)
+static void convname(char *a, uint8_t *q)
{
int i = (q[0] == '.') ? 0 : 1;
- for(; i < MAX_HOST_LEN-1 && *q; i++, q++)
+ 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
+ * Insert length of substrings instead of dots
*/
-static void
-undot(uint8_t * rip)
+static void undot(uint8_t * rip)
{
int i = 0, s = 0;
- while(rip[i]) i++;
- for(--i; i >= 0; i--) {
- if(rip[i] == '.') {
+ 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)
+static void log_message(char *filename, char *message)
{
FILE *logfile;
if (!daemonmode)
* converting to a length/string substring for that label.
*/
-static int
-getfileentry(FILE * fp, struct dns_entry *s, int verb)
+static int getfileentry(FILE * fp, struct dns_entry *s)
{
unsigned int a,b,c,d;
char *r, *name;
-restart:
- if(!(r = bb_get_line_from_file(fp)))
+ restart:
+ r = xmalloc_fgets(fp);
+ if (!r)
return -1;
- while(*r == ' ' || *r == '\t') {
+ while (*r == ' ' || *r == '\t') {
r++;
- if(!*r || *r == '#' || *r == '\n')
+ if (!*r || *r == '#' || *r == '\n')
goto restart; /* skipping empty/blank and commented lines */
}
name = r;
- while(*r != ' ' && *r != '\t')
+ while (*r != ' ' && *r != '\t')
r++;
*r++ = 0;
- if(sscanf(r,"%u.%u.%u.%u",&a,&b,&c,&d) != 4)
- goto restart; /* skipping wrong lines */
+ 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);
+ 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);
+ if (OPT_verbose)
+ fprintf(stderr, "\tname:%s, ip:%s\n", &(s->name[1]),s->ip);
- return 0; /* warningkiller */
+ return 0;
}
/*
* Read hostname/IP records from file
*/
-static void
-dnsentryinit(int verb)
+static void dnsentryinit(void)
{
FILE *fp;
struct dns_entry *m, *prev;
prev = dnsentry = NULL;
- if(!(fp = fopen(fileconf, "r")))
- bb_perror_msg_and_die("open %s",fileconf);
+ fp = xfopen(fileconf, "r");
while (1) {
- if(!(m = (struct dns_entry *)malloc(sizeof(struct dns_entry))))
- bb_perror_msg_and_die("malloc dns_entry");
+ m = xmalloc(sizeof(struct dns_entry));
m->next = NULL;
- if (getfileentry(fp, m, verb))
+ if (getfileentry(fp, m))
break;
if (prev == NULL)
/*
* Set up UDP socket
*/
-static int
-listen_socket(char *iface_addr, int listen_port)
+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");
+ s = xsocket(PF_INET, SOCK_DGRAM, 0);
#ifdef SO_REUSEADDR
if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&yes, sizeof(yes)) < 0)
bb_perror_msg_and_die("setsockopt() failed");
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);
+ xbind(s, (struct sockaddr *)&a, sizeof(a));
+ xlisten(s, 50);
sprintf(msg, "accepting UDP packets on addr:port %s:%d\n",
iface_addr, (int)listen_port);
log_message(LOG_FILE, msg);
* 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)
+static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
{
int i;
struct dns_entry *d=dnsentry;
char *p,*q;
q = (char *)&(qs[1]);
p = &(d->name[1]);
- fprintf(stderr, "\ntest: %d <%s> <%s> %d", strlen(p), p, q, strlen(q));
+ fprintf(stderr, "\n%s: %d/%d p:%s q:%s %d",
+ __FUNCTION__, strlen(p), (int)(d->name[0]), 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;
+ for (i = 1; i <= (int)(d->name[0]); i++)
+ if (tolower(qs[i]) != d->name[i])
+ break;
+ if (i > (int)(d->name[0])) {
#ifdef DEBUG
- fprintf(stderr, " OK");
+ fprintf(stderr, " OK");
#endif
- strcpy((char *)as, d->ip);
+ strcpy((char *)as, d->ip);
#ifdef DEBUG
- fprintf(stderr, " %s ", as);
+ fprintf(stderr, " as:%s\n", as);
#endif
return 0;
- }
- else if (type == REQ_PTR) { /* search by IP-address */
+ }
+ } 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);
+ d = d->next;
+ } while (d);
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)
+#define eret(s) do { fputs(s, stderr); return -1; } while (0)
+static int process_packet(uint8_t * buf)
{
struct dns_head *head;
struct dns_prop *qprop;
head = (struct dns_head *)buf;
if (head->nquer == 0)
- eret("no queries");
+ eret("no queries\n");
- if ((head->flags & 0x8000))
- eret("ignoring response packet");
+ if (head->flags & 0x8000)
+ eret("ignoring response packet\n");
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
+ next = answb = from + strlen((char *)from) + 1 + sizeof(struct dns_prop); // where to append answer block
outr.rlen = 0; // may change later
outr.r = NULL;
goto empty_packet;
// We have a standard query
-
- log_message(LOG_FILE, (char *)head);
- lookup_result = table_lookup(type, answstr, (uint8_t*)(&head[1]));
+ log_message(LOG_FILE, (char *)from);
+ lookup_result = table_lookup(type, answstr, (uint8_t*)from);
if (lookup_result != 0) {
outr.flags = 3 | 0x0400; //name do not exist and auth
goto empty_packet;
memcpy(next, (void *)answstr, outr.rlen);
next += outr.rlen;
- empty_packet:
+ empty_packet:
flags = ntohs(head->flags);
// clear rcode and RA, set responsebit and our new flags
/*
* Exit on signal
*/
-static void
-interrupt(int x)
+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 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;
+ char *sttl, *sport;
- 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)))
+ getopt32(argc, argv, "i:c:t:p:dv", &listen_interface, &fileconf, &sttl, &sport);
+ //if (option_mask32 & 0x1) // -i
+ //if (option_mask32 & 0x2) // -c
+ if (option_mask32 & 0x4) // -t
+ if (!(ttl = atol(sttl)))
bb_show_usage();
- if(sport)
- if(!(port = atol(sport)))
+ if (option_mask32 & 0x8) // -p
+ 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 (OPT_verbose) {
+ bb_info_msg("listen_interface: %s", listen_interface);
+ bb_info_msg("ttl: %d, port: %d", ttl, port);
+ bb_info_msg("fileconf: %s", fileconf);
}
- if(is_daemon())
-#if defined(__uClinux__)
+ if (OPT_daemon)
+#ifdef BB_NOMMU
/* 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 */
+#else
+ xdaemon(1, 0);
+#endif
- dnsentryinit(is_verbose());
+ dnsentryinit();
signal(SIGINT, interrupt);
signal(SIGPIPE, SIG_IGN);
FD_ZERO(&fdset);
FD_SET(udps, &fdset);
// Block until a message arrives
- if((r = select(udps + 1, &fdset, NULL, NULL, NULL)) < 0)
+ r = select(udps + 1, &fdset, NULL, NULL, NULL);
+ if (r < 0)
bb_perror_msg_and_die("select error");
- else
- if(r == 0)
+ if (r == 0)
bb_perror_msg_and_die("select spurious return");
- /* Can this test ever be false? */
+ /* Can this test ever be false? - yes */
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())
+ if (OPT_verbose)
fprintf(stderr, "\n--- Got UDP ");
log_message(LOG_FILE, "\n--- Got UDP ");
r, 0, (struct sockaddr *)&from,
fromlen);
}
- } // end if
- } // end while
+ } // end if
+ } // end while
return 0;
}
-
-
projects / oweals / busybox.git / blobdiff