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next part of ipv6-ization. dnsd code is "interesting"...

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This commit is contained in:
Denis Vlasenko
2007-01-12 14:57:37 +00:00
parent 6536a9b583
commit 2c91652bbc
3 changed files with 53 additions and 108 deletions
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110
networking/dnsd.c
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@@ -19,15 +19,15 @@
#include "busybox.h"
static char *fileconf = "/etc/dnsd.conf";
static const char *fileconf = "/etc/dnsd.conf";
#define LOCK_FILE "/var/run/dnsd.lock"
#define LOG_FILE "/var/log/dnsd.log"
// Must matct getopt32 call
// Must match getopt32 call
#define OPT_daemon (option_mask32 & 0x10)
#define OPT_verbose (option_mask32 & 0x20)
//#define DEBUG 1
#define DEBUG 0
enum {
MAX_HOST_LEN = 16, // longest host name allowed is 15
@@ -76,8 +76,6 @@ struct dns_entry { // element of known name, ip address and reversed ip address
};
static struct dns_entry *dnsentry = NULL;
// FIXME! unused! :(
static int daemonmode;
static uint32_t ttl = DEFAULT_TTL;
/*
@@ -108,21 +106,6 @@ static void undot(uint8_t * rip)
}
}
/*
* 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
@@ -191,31 +174,6 @@ static void dnsentryinit(void)
fclose(fp);
}
/*
* Set up UDP socket
*/
static int listen_socket(char *iface_addr, int listen_port)
{
struct sockaddr_in a;
char msg[100];
int sck;
sck = xsocket(PF_INET, SOCK_DGRAM, 0);
if (setsockopt_reuseaddr(sck) < 0)
bb_perror_msg_and_die("setsockopt() failed");
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");
xbind(sck, (struct sockaddr *)&a, sizeof(a));
xlisten(sck, 50);
sprintf(msg, "accepting UDP packets on addr:port %s:%d\n",
iface_addr, (int)listen_port);
log_message(LOG_FILE, msg);
return sck;
}
/*
* Look query up in dns records and return answer if found
* qs is the query string, first byte the string length
@@ -309,7 +267,7 @@ static int process_packet(uint8_t * buf)
goto empty_packet;
// We have a standard query
log_message(LOG_FILE, (char *)from);
bb_info_msg("%s", (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
@@ -363,27 +321,26 @@ static int process_packet(uint8_t * buf)
static void interrupt(int x)
{
unlink(LOCK_FILE);
write(2, "interrupt exiting\n", 18);
bb_error_msg("interrupt, exiting\n");
exit(2);
}
int dnsd_main(int argc, char **argv)
{
char *listen_interface = NULL;
char *sttl, *sport;
len_and_sockaddr *lsa;
int udps;
uint16_t port = 53;
uint8_t buf[MAX_PACK_LEN];
char *listen_interface = "0.0.0.0";
char *sttl, *sport;
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();
ttl = xatou_range(sttl, 1, 0xffffffff);
if (option_mask32 & 0x8) // -p
if (!(port = atol(sport)))
bb_show_usage();
port = xatou_range(sttl, 1, 0xffff);
if (OPT_verbose) {
bb_info_msg("listen_interface: %s", listen_interface);
@@ -391,13 +348,16 @@ int dnsd_main(int argc, char **argv)
bb_info_msg("fileconf: %s", fileconf);
}
if (OPT_daemon)
if (OPT_daemon) {
//FIXME: NOMMU will NOT set LOGMODE_SYSLOG!
#ifdef BB_NOMMU
/* reexec for vfork() do continue parent */
vfork_daemon_rexec(1, 0, argc, argv, "-d");
#else
xdaemon(1, 0);
#endif
logmode = LOGMODE_SYSLOG;
}
dnsentryinit();
@@ -411,7 +371,12 @@ int dnsd_main(int argc, char **argv)
signal(SIGURG, SIG_IGN);
#endif
udps = listen_socket(listen_interface, port);
lsa = host2sockaddr(listen_interface, port);
udps = xsocket(lsa->sa.sa_family, SOCK_DGRAM, 0);
xbind(udps, &lsa->sa, lsa->len);
// xlisten(udps, 50); - ?!! DGRAM sockets are never listened on I think?
bb_info_msg("Accepting UDP packets on %s",
xmalloc_sockaddr2dotted(&lsa->sa, lsa->len));
while (1) {
fd_set fdset;
@@ -420,6 +385,8 @@ int dnsd_main(int argc, char **argv)
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");
@@ -428,27 +395,26 @@ int dnsd_main(int argc, char **argv)
/* 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);
socklen_t fromlen = lsa->len;
// FIXME: need to get *DEST* address (to which of our addresses
// this query was directed), and reply from the same address.
// Or else we can exhibit usual UDP ugliness:
// [ip1.multihomed.ip2] <= query to ip1 <= peer
// [ip1.multihomed.ip2] => reply from ip2 => peer (confused)
r = recvfrom(udps, buf, sizeof(buf), 0, &lsa->sa, &fromlen);
if (OPT_verbose)
fprintf(stderr, "\n--- Got UDP ");
log_message(LOG_FILE, "\n--- Got UDP ");
bb_info_msg("Got UDP packet");
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;
if (r <= 0)
continue;
r = process_packet(buf);
if (r <= 0)
continue;
sendto(udps, buf, r, 0, &lsa->sa, fromlen);
}
}
}