From d3bac03988b104998c90dbce50e152668c3e4f5d Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Sat, 24 Mar 2007 12:13:04 +0000 Subject: dnsd: fix several buglets, make smaller --- networking/dnsd.c | 104 +++++++++++++++++++++--------------------------------- 1 file changed, 41 insertions(+), 63 deletions(-) (limited to 'networking/dnsd.c') diff --git a/networking/dnsd.c b/networking/dnsd.c index fb0c56cce..fd2f421d7 100644 --- a/networking/dnsd.c +++ b/networking/dnsd.c @@ -19,13 +19,6 @@ #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 0 @@ -75,9 +68,16 @@ struct dns_entry { // element of known name, ip address and reversed ip address char name[MAX_HOST_LEN]; }; -static struct dns_entry *dnsentry = NULL; +static struct dns_entry *dnsentry; 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. */ @@ -135,12 +135,12 @@ static int getfileentry(FILE * fp, struct dns_entry *s) while (*r != ' ' && *r != '\t') r++; *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); 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); undot((uint8_t*)s->rip); 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) { int i; - struct dns_entry *d=dnsentry; + struct dns_entry *d = dnsentry; do { #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]) break; if (i > (int)(d->name[0])) { -#if DEBUG - fprintf(stderr, " OK"); -#endif strcpy((char *)as, d->ip); #if DEBUG - fprintf(stderr, " as:%s\n", as); + fprintf(stderr, " OK as:%s\n", as); #endif - return 0; + 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; @@ -226,7 +222,6 @@ static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs) /* * Decode message and generate answer */ -#define eret(s) do { fputs(s, stderr); return -1; } while (0) static int process_packet(uint8_t * buf) { struct dns_head *head; @@ -241,11 +236,15 @@ static int process_packet(uint8_t * buf) answstr[0] = '\0'; head = (struct dns_head *)buf; - if (head->nquer == 0) - eret("no queries\n"); + if (head->nquer == 0) { + bb_error_msg("no queries"); + retunr -1; + } - if (head->flags & 0x8000) - eret("ignoring response packet\n"); + if (head->flags & 0x8000) { + bb_error_msg("ignoring response packet"); + retunr -1; + } from = (void *)&head[1]; // start of query string 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 outr.rlen = 4; // uint32_t IP - } - else + } 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 */ @@ -316,7 +314,7 @@ static int process_packet(uint8_t * buf) head->nauth = head->nadd = htons(0); head->nquer = htons(1); - packet_len = next - (void *)buf; + packet_len = (uint8_t *)next - buf; return packet_len; } @@ -325,7 +323,7 @@ static int process_packet(uint8_t * buf) */ static void interrupt(int x) { - unlink(LOCK_FILE); + /* unlink("/var/run/dnsd.lock"); */ bb_error_msg("interrupt, exiting\n"); 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) { - char *listen_interface = NULL; + const char *listen_interface = "0.0.0.0"; char *sttl, *sport; len_and_sockaddr *lsa; int udps; @@ -346,7 +344,7 @@ int dnsd_main(int argc, char **argv) if (option_mask32 & 0x4) // -t ttl = xatou_range(sttl, 1, 0xffffffff); if (option_mask32 & 0x8) // -p - port = xatou_range(sttl, 1, 0xffff); + port = xatou_range(sport, 1, 0xffff); if (OPT_verbose) { bb_info_msg("listen_interface: %s", listen_interface); @@ -355,7 +353,6 @@ int dnsd_main(int argc, char **argv) } if (OPT_daemon) { -//FIXME: NOMMU will NOT set LOGMODE_SYSLOG! #ifdef BB_NOMMU if (!re_execed) vfork_daemon_rexec(1, 0, argv); @@ -368,7 +365,7 @@ int dnsd_main(int argc, char **argv) dnsentryinit(); signal(SIGINT, interrupt); - signal(SIGPIPE, SIG_IGN); + /* why? signal(SIGPIPE, SIG_IGN); */ signal(SIGHUP, SIG_IGN); #ifdef SIGTSTP signal(SIGTSTP, SIG_IGN); @@ -377,50 +374,31 @@ int dnsd_main(int argc, char **argv) signal(SIGURG, SIG_IGN); #endif - lsa = xhost2sockaddr(listen_interface, port); + lsa = xdotted2sockaddr(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? + /* 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; 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 // 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) - bb_info_msg("Got UDP packet"); - - if (r < 12 || r > 512) { - bb_error_msg("invalid packet size"); - continue; - } - if (r <= 0) - continue; - r = process_packet(buf); - if (r <= 0) - continue; - sendto(udps, buf, r, 0, &lsa->sa, fromlen); + r = recvfrom(udps, buf, sizeof(buf), 0, &lsa->sa, &fromlen); + if (OPT_verbose) + bb_info_msg("Got UDP packet"); + if (r < 12 || r > 512) { + bb_error_msg("invalid packet size"); + continue; } + r = process_packet(buf); + if (r <= 0) + continue; + sendto(udps, buf, r, 0, &lsa->sa, fromlen); } } -- cgit v1.2.3