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

author: Denis Vlasenko <vda.linux@googlemail.com> 2007-01-12 14:57:37 +0000
committer: Denis Vlasenko <vda.linux@googlemail.com> 2007-01-12 14:57:37 +0000
commit: 2c91652bbcc82c794c26230806058b04f1711033 (patch)
tree: 1195f7c7fba68bdaf175d85432bf60a60a8c29f0 /networking/dnsd.c
parent: 6536a9b5833febe719988526a095a9cacb8a1042 (diff)
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1 files changed, 38 insertions, 72 deletions
diff --git a/networking/dnsd.c b/networking/dnsd.c
index 1fb9ccfe5..c3bd1610b 100644
--- a/networking/dnsd.c
+++ b/networking/dnsd.c
@@ -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;
 /*
@@ -109,21 +107,6 @@ 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
 * Assumes all host names are lower case only
@@ -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)))
+                ttl = xatou_range(sttl, 1, 0xffffffff);
-                        bb_show_usage();
        if (option_mask32 & 0x8) // -p
-                if (!(port = atol(sport)))
+                port = xatou_range(sttl, 1, 0xffff);
-                        bb_show_usage();
        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;
+                        socklen_t fromlen = lsa->len;
-                        int fromlen = sizeof(from);
+// FIXME: need to get *DEST* address (to which of our addresses
-                        r = recvfrom(udps, buf, sizeof(buf), 0,
+// this query was directed), and reply from the same address.
-                                     (struct sockaddr *)&from,
+// Or else we can exhibit usual UDP ugliness:
-                                     (void *)&fromlen);
+// [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  ");
+                                bb_info_msg("Got UDP packet");
-                        log_message(LOG_FILE, "\n--- Got UDP  ");
                        if (r < 12 || r > 512) {
                                bb_error_msg("invalid packet size");
                                continue;
                        }
-                        if (r > 0) {
+                        if (r <= 0)
-                                r = process_packet(buf);
+                                continue;
-                                if (r > 0)
+                        r = process_packet(buf);
-                                        sendto(udps, buf,
+                        if (r <= 0)
-                                               r, 0, (struct sockaddr *)&from,
+                                continue;
-                                               fromlen);
+                        sendto(udps, buf, r, 0, &lsa->sa, fromlen);
-                        }
+                }
-                } // end if
+        }
-        } // end while
-        return 0;
 }
author	Denis Vlasenko <vda.linux@googlemail.com>	2007-01-12 14:57:37 +0000
committer	Denis Vlasenko <vda.linux@googlemail.com>	2007-01-12 14:57:37 +0000
commit	2c91652bbcc82c794c26230806058b04f1711033 (patch)
tree	1195f7c7fba68bdaf175d85432bf60a60a8c29f0 /networking/dnsd.c
parent	6536a9b5833febe719988526a095a9cacb8a1042 (diff)
download	busybox-w32-2c91652bbcc82c794c26230806058b04f1711033.tar.gz busybox-w32-2c91652bbcc82c794c26230806058b04f1711033.tar.bz2 busybox-w32-2c91652bbcc82c794c26230806058b04f1711033.zip