emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

dnsd: fix several buglets, make smaller

Browse Source
This commit is contained in:
Denis Vlasenko 2007-03-24 12:13:04 +00:00
parent 9067f13be0
commit d3bac03988
2 changed files with 42 additions and 64 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/usage.h
View File

@ -673,7 +673,7 @@
" -c Config filename\n" \ " -c Config filename\n" \
" -t TTL in seconds\n" \ " -t TTL in seconds\n" \
" -p Listening port\n" \ " -p Listening port\n" \
" -i Listening iface ip (default all)\n" \ " -i Listening ip (default all)\n" \
" -d Daemonize" " -d Daemonize"
#define dos2unix_trivial_usage \ #define dos2unix_trivial_usage \

80
networking/dnsd.c
View File

@ -19,13 +19,6 @@
#include "busybox.h" #include "busybox.h"
static const char *fileconf = "/etc/dnsd.conf";
#define LOCK_FILE "/var/run/dnsd.lock"
// Must match getopt32 call
#define OPT_daemon (option_mask32 & 0x10)
#define OPT_verbose (option_mask32 & 0x20)
//#define DEBUG 1 //#define DEBUG 1
#define DEBUG 0 #define DEBUG 0
@ -75,9 +68,16 @@ struct dns_entry { // element of known name, ip address and reversed ip address
char name[MAX_HOST_LEN]; char name[MAX_HOST_LEN];
}; };
static struct dns_entry *dnsentry = NULL; static struct dns_entry *dnsentry;
static uint32_t ttl = DEFAULT_TTL; static uint32_t ttl = DEFAULT_TTL;
static const char *fileconf = "/etc/dnsd.conf";
// Must match getopt32 call
#define OPT_daemon (option_mask32 & 0x10)
#define OPT_verbose (option_mask32 & 0x20)
/* /*
* Convert host name from C-string to dns length/string. * Convert host name from C-string to dns length/string.
*/ */
@ -135,12 +135,12 @@ static int getfileentry(FILE * fp, struct dns_entry *s)
while (*r != ' ' && *r != '\t') while (*r != ' ' && *r != '\t')
r++; r++;
*r++ = '\0'; *r++ = '\0';
if (sscanf(r, "%u.%u.%u.%u", &a, &b, &c, &d) != 4) { if (sscanf(r, ".%u.%u.%u.%u"+1, &a, &b, &c, &d) != 4) {
free(line); free(line);
goto restart; /* skipping wrong lines */ goto restart; /* skipping wrong lines */
} }
sprintf(s->ip, "%u.%u.%u.%u", a, b, c, d); sprintf(s->ip, ".%u.%u.%u.%u"+1, a, b, c, d);
sprintf(s->rip, ".%u.%u.%u.%u", d, c, b, a); sprintf(s->rip, ".%u.%u.%u.%u", d, c, b, a);
undot((uint8_t*)s->rip); undot((uint8_t*)s->rip);
convname(s->name, (uint8_t*)name); convname(s->name, (uint8_t*)name);
@ -185,7 +185,7 @@ static void dnsentryinit(void)
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; int i;
struct dns_entry *d=dnsentry; struct dns_entry *d = dnsentry;
do { do {
#if DEBUG #if DEBUG
@ -201,17 +201,13 @@ static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
if (tolower(qs[i]) != d->name[i]) if (tolower(qs[i]) != d->name[i])
break; break;
if (i > (int)(d->name[0])) { if (i > (int)(d->name[0])) {
#if DEBUG
fprintf(stderr, " OK");
#endif
strcpy((char *)as, d->ip); strcpy((char *)as, d->ip);
#if DEBUG #if DEBUG
fprintf(stderr, " as:%s\n", as); fprintf(stderr, " OK as:%s\n", as);
#endif #endif
return 0; return 0;
} }
} else } else if (type == REQ_PTR) { /* search by IP-address */
if (type == REQ_PTR) { /* search by IP-address */
if (!strncmp((char*)&d->rip[1], (char*)&qs[1], strlen(d->rip)-1)) { if (!strncmp((char*)&d->rip[1], (char*)&qs[1], strlen(d->rip)-1)) {
strcpy((char *)as, d->name); strcpy((char *)as, d->name);
return 0; return 0;
@ -226,7 +222,6 @@ static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
/* /*
* Decode message and generate answer * Decode message and generate answer
*/ */
#define eret(s) do { fputs(s, stderr); return -1; } while (0)
static int process_packet(uint8_t * buf) static int process_packet(uint8_t * buf)
{ {
struct dns_head *head; struct dns_head *head;
@ -241,11 +236,15 @@ static int process_packet(uint8_t * buf)
answstr[0] = '\0'; answstr[0] = '\0';
head = (struct dns_head *)buf; head = (struct dns_head *)buf;
if (head->nquer == 0) if (head->nquer == 0) {
eret("no queries\n"); bb_error_msg("no queries");
retunr -1;
}
if (head->flags & 0x8000) if (head->flags & 0x8000) {
eret("ignoring response packet\n"); bb_error_msg("ignoring response packet");
retunr -1;
}
from = (void *)&head[1]; // start of query string from = (void *)&head[1]; // start of query string
next = answb = from + strlen((char *)from) + 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
@ -286,8 +285,7 @@ static int process_packet(uint8_t * buf)
} }
memcpy(answstr, &a.s_addr, 4); // save before a disappears memcpy(answstr, &a.s_addr, 4); // save before a disappears
outr.rlen = 4; // uint32_t IP outr.rlen = 4; // uint32_t IP
} } else
else
outr.rlen = strlen((char *)answstr) + 1; // a host name outr.rlen = strlen((char *)answstr) + 1; // a host name
outr.r = answstr; // 32 bit ip or a host name outr.r = answstr; // 32 bit ip or a host name
outr.flags |= 0x0400; /* authority-bit */ outr.flags |= 0x0400; /* authority-bit */
@ -316,7 +314,7 @@ static int process_packet(uint8_t * buf)
head->nauth = head->nadd = htons(0); head->nauth = head->nadd = htons(0);
head->nquer = htons(1); head->nquer = htons(1);
packet_len = next - (void *)buf; packet_len = (uint8_t *)next - buf;
return packet_len; return packet_len;
} }
@ -325,7 +323,7 @@ static int process_packet(uint8_t * buf)
*/ */
static void interrupt(int x) static void interrupt(int x)
{ {
unlink(LOCK_FILE); /* unlink("/var/run/dnsd.lock"); */
bb_error_msg("interrupt, exiting\n"); bb_error_msg("interrupt, exiting\n");
exit(2); exit(2);
} }
@ -333,7 +331,7 @@ static void interrupt(int x)
int dnsd_main(int argc, char **argv); int dnsd_main(int argc, char **argv);
int dnsd_main(int argc, char **argv) int dnsd_main(int argc, char **argv)
{ {
char *listen_interface = NULL; const char *listen_interface = "0.0.0.0";
char *sttl, *sport; char *sttl, *sport;
len_and_sockaddr *lsa; len_and_sockaddr *lsa;
int udps; int udps;
@ -346,7 +344,7 @@ int dnsd_main(int argc, char **argv)
if (option_mask32 & 0x4) // -t if (option_mask32 & 0x4) // -t
ttl = xatou_range(sttl, 1, 0xffffffff); ttl = xatou_range(sttl, 1, 0xffffffff);
if (option_mask32 & 0x8) // -p if (option_mask32 & 0x8) // -p
port = xatou_range(sttl, 1, 0xffff); port = xatou_range(sport, 1, 0xffff);
if (OPT_verbose) { if (OPT_verbose) {
bb_info_msg("listen_interface: %s", listen_interface); bb_info_msg("listen_interface: %s", listen_interface);
@ -355,7 +353,6 @@ int dnsd_main(int argc, char **argv)
} }
if (OPT_daemon) { if (OPT_daemon) {
//FIXME: NOMMU will NOT set LOGMODE_SYSLOG!
#ifdef BB_NOMMU #ifdef BB_NOMMU
if (!re_execed) if (!re_execed)
vfork_daemon_rexec(1, 0, argv); vfork_daemon_rexec(1, 0, argv);
@ -368,7 +365,7 @@ int dnsd_main(int argc, char **argv)
dnsentryinit(); dnsentryinit();
signal(SIGINT, interrupt); signal(SIGINT, interrupt);
signal(SIGPIPE, SIG_IGN); /* why? signal(SIGPIPE, SIG_IGN); */
signal(SIGHUP, SIG_IGN); signal(SIGHUP, SIG_IGN);
#ifdef SIGTSTP #ifdef SIGTSTP
signal(SIGTSTP, SIG_IGN); signal(SIGTSTP, SIG_IGN);
@ -377,30 +374,15 @@ int dnsd_main(int argc, char **argv)
signal(SIGURG, SIG_IGN); signal(SIGURG, SIG_IGN);
#endif #endif
lsa = xhost2sockaddr(listen_interface, port); lsa = xdotted2sockaddr(listen_interface, port);
udps = xsocket(lsa->sa.sa_family, SOCK_DGRAM, 0); udps = xsocket(lsa->sa.sa_family, SOCK_DGRAM, 0);
xbind(udps, &lsa->sa, lsa->len); xbind(udps, &lsa->sa, lsa->len);
// xlisten(udps, 50); - ?!! DGRAM sockets are never listened on I think? /* xlisten(udps, 50); - ?!! DGRAM sockets are never listened on I think? */
bb_info_msg("Accepting UDP packets on %s", bb_info_msg("Accepting UDP packets on %s",
xmalloc_sockaddr2dotted(&lsa->sa, lsa->len)); xmalloc_sockaddr2dotted(&lsa->sa, lsa->len));
while (1) { while (1) {
fd_set fdset;
int r; int r;
FD_ZERO(&fdset);
FD_SET(udps, &fdset);
// Block until a message arrives
// FIXME: Fantastic. select'ing on just one fd??
// Why no just block on it doing recvfrom() ?
r = select(udps + 1, &fdset, NULL, NULL, NULL);
if (r < 0)
bb_perror_msg_and_die("select error");
if (r == 0)
bb_perror_msg_and_die("select spurious return");
/* Can this test ever be false? - yes */
if (FD_ISSET(udps, &fdset)) {
socklen_t fromlen = lsa->len; socklen_t fromlen = lsa->len;
// FIXME: need to get *DEST* address (to which of our addresses // FIXME: need to get *DEST* address (to which of our addresses
// this query was directed), and reply from the same address. // this query was directed), and reply from the same address.
@ -410,17 +392,13 @@ int dnsd_main(int argc, char **argv)
r = recvfrom(udps, buf, sizeof(buf), 0, &lsa->sa, &fromlen); r = recvfrom(udps, buf, sizeof(buf), 0, &lsa->sa, &fromlen);
if (OPT_verbose) if (OPT_verbose)
bb_info_msg("Got UDP packet"); bb_info_msg("Got UDP packet");
if (r < 12 || r > 512) { if (r < 12 || r > 512) {
bb_error_msg("invalid packet size"); bb_error_msg("invalid packet size");
continue; continue;
} }
if (r <= 0)
continue;
r = process_packet(buf); r = process_packet(buf);
if (r <= 0) if (r <= 0)
continue; continue;
sendto(udps, buf, r, 0, &lsa->sa, fromlen); sendto(udps, buf, r, 0, &lsa->sa, fromlen);
} }
}
} }