2155 lines
58 KiB
C
Executable file
2155 lines
58 KiB
C
Executable file
/* nonamed - Not a name daemon, but plays one on TV.
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* Author: Kees J. Bot
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* 29 Nov 1994
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*/
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static const char version[] = "2.7";
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/* Use the file reading gethostent() family of functions. */
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#define sethostent _sethostent
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#define gethostent _gethostent
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#define endhostent _endhostent
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#define nil ((void*)0)
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#include <sys/types.h>
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#include <stdio.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include <time.h>
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#include <limits.h>
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#include <signal.h>
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#include <assert.h>
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#include <sys/stat.h>
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#include <sys/ioctl.h>
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#include <sys/asynchio.h>
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#include <net/hton.h>
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#include <net/netlib.h>
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#include <net/gen/in.h>
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#include <net/gen/inet.h>
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#include <net/gen/nameser.h>
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#include <net/gen/resolv.h>
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#include <net/gen/netdb.h>
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#include <net/gen/socket.h>
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#include <net/gen/tcp.h>
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#include <net/gen/tcp_io.h>
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#include <net/gen/udp.h>
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#include <net/gen/udp_hdr.h>
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#include <net/gen/udp_io.h>
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#include <net/gen/dhcp.h>
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#include <minix/paths.h>
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#define HTTL 3600L /* Default time to live for /etc/hosts data. */
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#define SHORT_TIMEOUT 2 /* If you expect an answer soon. */
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#define MEDIUM_TIMEOUT 4 /* Soon, but not that soon. */
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#define LONG_TIMEOUT 300 /* For stream connections to a real named. */
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#define N_IDS 256 /* Keep track of this many queries. */
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#define N_DATAMAX (4096*sizeof(char *)) /* Default response cache size. */
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#define N_NAMEDS 8 /* Max # name daemons we can keep track of. */
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#define NO_FD (-1) /* No name daemon channel here. */
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#define T_NXD ((u16_t) -1) /* A "type" signalling a nonexistent domain. */
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/* Can't do async I/O under standard Minix, so forget about TCP. */
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#define DO_TCP (__minix_vmd || !__minix)
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/* Host data, file to store our process id in, our cache, DHCP's cache. */
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static char HOSTS[]= _PATH_HOSTS;
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static char PIDFILE[]= "/usr/run/nonamed.pid";
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static char NNCACHE[]= "/usr/adm/nonamed.cache";
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static char DHCPCACHE[]= _PATH_DHCPCACHE;
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/* Magic string to head the cache file. */
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static char MAGIC[4]= "NND\2";
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#define arraysize(a) (sizeof(a) / sizeof((a)[0]))
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#define arraylimit(a) ((a) + arraysize(a))
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#define between(a, c, z) ((unsigned) ((c) - (a)) <= (unsigned) ((z) - (a)))
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/* The start of time and the far future. */
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#define IMMEDIATE ((time_t) 0)
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#define NEVER ((time_t) ((time_t) -1 < 0 ? LONG_MAX : ULONG_MAX))
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static unsigned debug; /* Debug level. */
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static time_t now; /* Current time. */
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static u32_t stale; /* Extension time for stale data. */
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static u32_t httl; /* TTL for /etc/hosts data. */
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static int reinit, done; /* Reinit config / program is done. */
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static int single; /* Run single on a nondefault interface. */
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static void report(const char *label)
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{
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fprintf(stderr, "nonamed: %s: %s\n", label, strerror(errno));
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}
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static void fatal(const char *label)
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{
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report(label);
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if (debug >= 3) { fflush(nil); abort(); }
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exit(1);
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}
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static void *allocate(void *mem, size_t size)
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{
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if ((mem= realloc(mem, size)) == nil) fatal("malloc()");
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return mem;
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}
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static void deallocate(void *mem)
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{
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free(mem);
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}
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static char *timegmt(time_t t)
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/* Simple "time in seconds to GMT time today" converter. */
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{
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unsigned h, m, s;
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static char asctime[sizeof("00:00:00")];
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s= t % 60;
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t /= 60;
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m= t % 60;
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t /= 60;
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h= t % 24;
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sprintf(asctime, "%02u:%02u:%02u", h, m, s);
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return asctime;
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}
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static char *nowgmt(void)
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{
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return timegmt(now);
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}
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#define PC(n) ((void) sizeof(char [sizeof(*(n)) == 1]), (char *) (n))
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#define namecpy(n1, n2) strcpy(PC(n1), PC(n2))
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#define namecat(n1, n2) strcat(PC(n1), PC(n2))
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#define namechr(n, c) ((u8_t *) strchr(PC(n), (c)))
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#define namecmp(n1, n2) strcasecmp(PC(n1), PC(n2))
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#define namencmp(n1, n2, len) strncasecmp(PC(n1), PC(n2), len)
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typedef struct dns { /* A DNS packet. */
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dns_hdr_t hdr; /* DNS header. */
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u8_t data[PACKETSZ - sizeof(dns_hdr_t)]; /* DNS data. */
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} dns_t;
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/* Addres of DNS packet to octet address, or vv. */
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#define dns2oct(dp) ((u8_t *) (dp))
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#define oct2dns(dp) ((dns_t *) (dp))
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typedef struct query { /* One cached answer to a query. */
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struct query *less; /* Less recently used. */
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struct query *more; /* More recently used. */
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time_t age; /* Time it was added. */
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time_t stale; /* Time it goes stale by TTL. */
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u16_t usage; /* Counts of queries answered. */
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u8_t flags; /* QF_REFRESH. */
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size_t size; /* Size of DNS packet. */
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dns_t dns; /* Answer to query as a DNS packet. */
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} query_t;
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#define QF_REFRESH 0x01 /* This stale data must be refreshed. */
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#define QU_SHIFT 1 /* To shift usage by when evicting. */
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/* Size of new query_t or existing query_t. */
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#define query_allocsize(dnssize) (offsetof(query_t, dns) + (dnssize))
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#define query_size(qp) query_allocsize((qp)->size)
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static query_t *mru, *lru; /* Most and least recently used answers. */
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static int q_refresh; /* Set when an entry needs refreshing. */
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static void pack16(u8_t *buf, u16_t s)
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/* Pack a 16 bit value into a byte array. */
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{
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buf[0]= ((u8_t *) &s)[0];
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buf[1]= ((u8_t *) &s)[1];
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}
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static void pack32(u8_t *buf, u32_t l)
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/* Pack a 32 bit value into a byte array. */
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{
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buf[0]= ((u8_t *) &l)[0];
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buf[1]= ((u8_t *) &l)[1];
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buf[2]= ((u8_t *) &l)[2];
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buf[3]= ((u8_t *) &l)[3];
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}
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static u16_t upack16(u8_t *buf)
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/* Unpack a 16 bit value from a byte array. */
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{
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u16_t s;
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((u8_t *) &s)[0]= buf[0];
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((u8_t *) &s)[1]= buf[1];
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return s;
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}
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static u32_t upack32(u8_t *buf)
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/* Unpack a 32 bit value from a byte array. */
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{
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u32_t l;
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((u8_t *) &l)[0]= buf[0];
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((u8_t *) &l)[1]= buf[1];
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((u8_t *) &l)[2]= buf[2];
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((u8_t *) &l)[3]= buf[3];
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return l;
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}
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/* Encoding of RRs: i(paddr), d(omain), l(ong), c(har), s(tring), (s)h(ort). */
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static char *encoding[] = {
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"c*", /* anything unknown is c* */
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"i", /* A */
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"d", /* NS */
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"d", /* MD */
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"d", /* MF */
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"d", /* CNAME */
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"ddlllll", /* SOA */
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"d", /* MB */
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"d", /* MG */
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"d", /* MR */
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"c*", /* NULL */
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"icc*", /* WKS */
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"d", /* PTR */
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"ss", /* HINFO */
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"dd", /* MINFO */
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"hd", /* MX */
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"s*", /* TXT */
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};
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static char *itoa(char *fmt, u32_t i)
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{
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static char output[32 + 3 * sizeof(i)];
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sprintf(output, fmt, (unsigned long) i);
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return output;
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}
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static char *classname(unsigned class)
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/* Class name of a resource record, for debug purposes. */
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{
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static char *classes[] = { "IN", "CS", "CHAOS", "HS" };
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if ((class - C_IN) < arraysize(classes)) return classes[class - C_IN];
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return itoa("C_%u", class);
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}
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static char *typename(unsigned type)
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/* Type name of a resource record, for debug purposes. */
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{
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static char type_A[][6] = {
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"A", "NS", "MD", "MF", "CNAME", "SOA", "MB", "MG", "MR", "NULL",
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"WKS", "PTR", "HINFO", "MINFO", "MX", "TXT",
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};
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static char type_AXFR[][6] = {
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"AXFR", "MAILB", "MAILA", "ANY",
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};
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if ((type - T_A) < arraysize(type_A)) return type_A[type - T_A];
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if ((type - T_AXFR) < arraysize(type_AXFR)) return type_AXFR[type - T_AXFR];
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return itoa("T_%u", type);
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}
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static int print_qrr(dns_t *dp, size_t size, u8_t *cp0, int q)
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/* Print a query (q) or resource record (!q) from 'cp0' in a DNS packet for
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* debug purposes. Return number of bytes skipped or -1 on error.
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*/
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{
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u8_t name[MAXDNAME+1];
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u8_t *cp;
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char *ep;
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u8_t *dlim, *rlim;
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u16_t type, class, rdlength;
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u32_t ttl;
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int r;
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cp= cp0;
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dlim= dns2oct(dp) + size;
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r= dn_expand(dns2oct(dp), dlim, cp, name, MAXDNAME);
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if (r == -1) return -1;
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cp += r;
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if (cp + 2 * sizeof(u16_t) > dlim) return -1;
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type= ntohs(upack16(cp));
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cp += sizeof(u16_t);
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class= ntohs(upack16(cp));
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cp += sizeof(u16_t);
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printf("%-25s", (char *) name);
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if (q) {
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/* We're just printing a query segment, stop right here. */
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printf(" %8s", classname(class));
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printf(" %-5s", typename(type));
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return cp - cp0;
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}
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if (cp + sizeof(u32_t) + sizeof(u16_t) > dlim) return -1;
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ttl= ntohl(upack32(cp));
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cp += sizeof(u32_t);
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rdlength= ntohs(upack16(cp));
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cp += sizeof(u16_t);
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if (cp + rdlength > dlim) return -1;
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rlim = cp + rdlength;
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printf(" %5lu", (unsigned long) ttl);
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printf(" %s", classname(class));
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printf(" %-5s", typename(type));
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ep= type < arraysize(encoding) ? encoding[type] : encoding[0];
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while (*ep != 0) {
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switch (*ep++) {
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case 'i':
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if (cp + sizeof(u32_t) > rlim) return -1;
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printf(" %s", inet_ntoa(upack32(cp)));
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cp += sizeof(u32_t);
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break;
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case 'l':
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if (cp + sizeof(u32_t) > rlim) return -1;
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printf(" %ld", (long)(i32_t) ntohl(upack32(cp)));
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cp += sizeof(u32_t);
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break;
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case 'd':
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r= dn_expand(dns2oct(dp), dlim, cp, name, MAXDNAME);
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if (r == -1) return -1;
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printf(" %s", (char *) name);
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cp += r;
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break;
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case 'c':
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if (cp >= rlim) return -1;
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printf(" %02X", *cp++);
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break;
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case 's':
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r= *cp + 1;
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if (cp + r > rlim) return -1;
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printf(" \"%.*s\"", *cp, (char *) (cp + 1));
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cp += r;
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break;
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case 'h':
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if (cp + sizeof(u16_t) > rlim) return -1;
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printf(" %u", ntohs(upack16(cp)));
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cp += sizeof(u16_t);
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break;
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}
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if (*ep == '*') ep= cp < rlim ? ep-1 : ep+1;
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}
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return cp - cp0;
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}
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static void dns_tell(int indent, dns_t *dp, size_t size)
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/* Explain a DNS packet, for debug purposes. */
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{
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u8_t *cp;
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int r, i;
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unsigned count[4];
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static char label[4][4]= { "QD:", "AN:", "NS:", "AR:" };
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static char rcodes[][9] = {
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"NOERROR", "FORMERR", "SERVFAIL", "NXDOMAIN", "NOTIMP", "REFUSED"
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};
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if (size < sizeof(dns_hdr_t)) return;
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printf("%*s", indent, "");
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printf("DNS %s:", (dp->hdr.dh_flag1 & DHF_QR) ? "reply" : "query");
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r= dp->hdr.dh_flag2 & DHF_RCODE;
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printf(" %s", r < arraysize(rcodes) ? rcodes[r] : itoa("ERR_%lu", r));
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if (dp->hdr.dh_flag1 & DHF_AA) printf(" AA");
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if (dp->hdr.dh_flag1 & DHF_TC) printf(" TC");
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if (dp->hdr.dh_flag1 & DHF_RD) printf(" RD");
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if (dp->hdr.dh_flag2 & DHF_RA) printf(" RA");
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#ifdef DHF_AD
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if (dp->hdr.dh_flag2 & DHF_AD) printf(" AD");
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if (dp->hdr.dh_flag2 & DHF_CD) printf(" CD");
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#endif
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fputc('\n', stdout);
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count[0]= ntohs(dp->hdr.dh_qdcount);
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count[1]= ntohs(dp->hdr.dh_ancount);
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count[2]= ntohs(dp->hdr.dh_nscount);
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count[3]= ntohs(dp->hdr.dh_arcount);
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cp = dp->data;
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for (i= 0; i < 4; i++) {
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while (count[i] > 0) {
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printf("%*s", indent, "");
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printf(" %s ", label[i]);
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r= print_qrr(dp, size, cp, (i == 0));
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fputc('\n', stdout);
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if (r == -1) return;
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cp += r;
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count[i]--;
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}
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}
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}
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static u32_t dns_ttl(dns_t *dp, size_t size, u32_t delta)
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/* Compute the minimum TTL of all RRs in a DNS packet and subtract delta from
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* all TTLs. (We are actually only interested in the minimum (delta = 0) or
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* the subtraction (delta > 0). It was easier to roll this into one routine.)
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*/
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{
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u8_t *cp, *rdp, *dlim;
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int r, i, hasttl, hassoa;
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unsigned type, count[4];
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u32_t ttl, minimum, minttl;
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unsigned rcode;
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u8_t name[MAXDNAME+1];
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hasttl= hassoa= 0;
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minttl= 365*24*3600L;
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dlim= dns2oct(dp) + size;
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if (size < sizeof(dns_hdr_t)) return 0;
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rcode= dp->hdr.dh_flag2 & DHF_RCODE;
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count[0]= ntohs(dp->hdr.dh_qdcount);
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count[1]= ntohs(dp->hdr.dh_ancount);
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count[2]= ntohs(dp->hdr.dh_nscount);
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count[3]= ntohs(dp->hdr.dh_arcount);
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cp = dp->data;
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for (i= 0; i < 4 && cp < dlim; i++) {
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while (count[i] > 0) {
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r= dn_expand(dns2oct(dp), dlim, cp, name, MAXDNAME);
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if (r == -1) break;
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cp += r + 2 * sizeof(u16_t);
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if (i != 0) {
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if (cp + sizeof(u32_t) + sizeof(u16_t) > dlim) break;
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type= upack16(cp - 2 * sizeof(u16_t));
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ttl= ntohl(upack32(cp));
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ttl= ttl < delta ? 0 : ttl - delta;
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if (rcode == NXDOMAIN && i == 2 && type == HTONS(T_SOA)) {
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rdp= cp + sizeof(u32_t) + sizeof(u16_t);
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r= dn_expand(dns2oct(dp), dlim, rdp, name, MAXDNAME);
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if (r == -1) break;
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rdp += r;
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r= dn_expand(dns2oct(dp), dlim, rdp, name, MAXDNAME);
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if (r == -1) break;
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rdp += r + 4 * sizeof(u32_t);
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if (rdp + sizeof(u32_t) > dlim) break;
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minimum= ntohl(upack32(rdp));
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if (ttl > minimum) ttl= minimum;
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hassoa= 1;
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}
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if (delta != 0) pack32(cp, htonl(ttl));
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if (ttl < minttl) minttl= ttl;
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hasttl= 1;
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cp += sizeof(u32_t);
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cp += sizeof(u16_t) + ntohs(upack16(cp));
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}
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count[i]--;
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}
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}
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return ((rcode == NOERROR && hasttl) || (rcode == NXDOMAIN && hassoa))
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? minttl : 0;
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}
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/* Total cached query data. */
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static size_t n_datamax= N_DATAMAX;
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static size_t n_data;
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static query_t *extract_query(query_t *qp)
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/* Take a query out of the query cache. */
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{
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assert(qp != nil);
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*(qp->less != nil ? &qp->less->more : &lru) = qp->more;
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*(qp->more != nil ? &qp->more->less : &mru) = qp->less;
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n_data -= query_size(qp);
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return qp;
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}
|
|
|
|
static query_t *get_query(u8_t *name, unsigned type)
|
|
/* Find a query and if so remove it from the cache and return it. */
|
|
{
|
|
query_t *qp, *less;
|
|
u8_t qname[MAXDNAME+1];
|
|
int r;
|
|
|
|
for (qp= mru; qp != nil; qp= less) {
|
|
less= qp->less;
|
|
if (qp->stale <= now - stale) {
|
|
/* This answer has expired. */
|
|
deallocate(extract_query(qp));
|
|
} else {
|
|
r= dn_expand(dns2oct(&qp->dns), dns2oct(&qp->dns) + qp->size,
|
|
qp->dns.data, qname, MAXDNAME);
|
|
if (r == -1) continue;
|
|
if (namecmp(qname, name) == 0 && upack16(qp->dns.data+r) == type) {
|
|
/* Found an answer to the query. */
|
|
return extract_query(qp);
|
|
}
|
|
}
|
|
}
|
|
return nil;
|
|
}
|
|
|
|
static void insert_query(query_t *qp)
|
|
/* (Re)insert a query into the cache. */
|
|
{
|
|
*(qp->less != nil ? &qp->less->more : &lru) = qp;
|
|
*(qp->more != nil ? &qp->more->less : &mru) = qp;
|
|
n_data += query_size(qp);
|
|
|
|
/* Try to delete the LRU while there is too much memory in use. If
|
|
* its usage count is too high then it gets a second chance.
|
|
*/
|
|
while (n_data > n_datamax && lru != nil) {
|
|
if ((lru->usage >>= QU_SHIFT) == 0 || lru->stale <= now - stale) {
|
|
deallocate(extract_query(lru));
|
|
} else {
|
|
lru->less= mru; /* Make list circular. */
|
|
mru->more= lru;
|
|
mru= lru; /* Move one over, making LRU the MRU. */
|
|
lru= lru->more;
|
|
lru->less= nil; /* Break the circle. */
|
|
mru->more= nil;
|
|
}
|
|
}
|
|
|
|
if (debug >= 2) {
|
|
unsigned n= 0;
|
|
for (qp= mru; qp != nil; qp= qp->less) n++;
|
|
printf("%u cached repl%s, %u bytes, sbrk(0) = %u\n",
|
|
n, n == 1 ? "y" : "ies",
|
|
(unsigned) n_data,
|
|
(unsigned) sbrk(0));
|
|
}
|
|
}
|
|
|
|
static void put_query(query_t *qp)
|
|
/* Add a new query to the cache as the MRU. */
|
|
{
|
|
qp->less= mru;
|
|
qp->more= nil;
|
|
insert_query(qp);
|
|
}
|
|
|
|
static void cache2file(void)
|
|
/* Store the cached data into the cache file. */
|
|
{
|
|
FILE *fp;
|
|
query_t *qp;
|
|
u8_t data[4+1+2+2];
|
|
u16_t usage;
|
|
char newcache[sizeof(NNCACHE) + sizeof(".new")];
|
|
|
|
if (single) return;
|
|
|
|
strcpy(newcache, NNCACHE);
|
|
strcat(newcache, ".new");
|
|
|
|
if ((fp= fopen(newcache, "w")) == nil) {
|
|
if ((errno != ENOENT && errno != EROFS) || debug >= 2) report(newcache);
|
|
return;
|
|
}
|
|
if (debug >= 2) printf("Writing %s:\n", newcache);
|
|
|
|
/* Magic number: */
|
|
fwrite(MAGIC, 1, sizeof(MAGIC), fp);
|
|
|
|
for (qp= lru; qp != nil; qp= qp->more) {
|
|
if (qp->stale <= now - stale) continue;
|
|
if (debug >= 2) {
|
|
printf("Usage = %u, Age = %ld, Flags = %02X:\n",
|
|
qp->usage, (long) (now - qp->age), qp->flags);
|
|
dns_tell(2, &qp->dns, qp->size);
|
|
}
|
|
pack32(data+0, htonl(qp->age));
|
|
data[4]= qp->flags;
|
|
pack16(data+5, htons(qp->size));
|
|
pack16(data+7, htons(qp->usage));
|
|
fwrite(data, 1, sizeof(data), fp);
|
|
fwrite(&qp->dns, 1, qp->size, fp);
|
|
if (ferror(fp)) break;
|
|
}
|
|
|
|
if (ferror(fp) || fclose(fp) == EOF) {
|
|
report(newcache);
|
|
(void) unlink(newcache);
|
|
return;
|
|
}
|
|
|
|
if (debug >= 2) printf("mv %s %s\n", newcache, NNCACHE);
|
|
if (rename(newcache, NNCACHE) < 0) {
|
|
fprintf(stderr, "nonamed: mv %s %s: %s\n",
|
|
newcache, NNCACHE, strerror(errno));
|
|
(void) unlink(newcache);
|
|
}
|
|
}
|
|
|
|
static void file2cache(void)
|
|
/* Read cached data from the cache file. */
|
|
{
|
|
query_t *qp;
|
|
FILE *fp;
|
|
u8_t data[4+1+2+2];
|
|
size_t dlen;
|
|
|
|
if (single) return;
|
|
|
|
if ((fp= fopen(NNCACHE, "r")) == nil) {
|
|
if (errno != ENOENT || debug >= 2) report(NNCACHE);
|
|
return;
|
|
}
|
|
if (debug >= 2) printf("Reading %s:\n", NNCACHE);
|
|
|
|
/* Magic number? */
|
|
fread(data, 1, sizeof(MAGIC), fp);
|
|
if (ferror(fp) || memcmp(MAGIC, data, sizeof(MAGIC)) != 0) goto err;
|
|
|
|
for (;;) {
|
|
fread(data, 1, sizeof(data), fp);
|
|
if (feof(fp) || ferror(fp)) break;
|
|
dlen= ntohs(upack16(data+5));
|
|
qp= allocate(nil, query_allocsize(dlen));
|
|
qp->age= htonl(upack32(data+0));
|
|
qp->flags= data[4];
|
|
if (qp->flags & QF_REFRESH) q_refresh= 1;
|
|
qp->size= dlen;
|
|
qp->usage= htons(upack16(data+7));
|
|
fread(&qp->dns, 1, qp->size, fp);
|
|
if (feof(fp) || ferror(fp)) {
|
|
deallocate(qp);
|
|
goto err;
|
|
}
|
|
qp->stale= qp->age + dns_ttl(&qp->dns, dlen, 0);
|
|
if (debug >= 2) {
|
|
printf("Usage = %u, Age = %ld, Flags = %02X:\n",
|
|
qp->usage, (long) (now - qp->age), qp->flags);
|
|
dns_tell(2, &qp->dns, dlen);
|
|
}
|
|
put_query(qp);
|
|
}
|
|
if (ferror(fp)) {
|
|
err:
|
|
/* The cache file did not end at EOF or is otherwise a mess. */
|
|
fprintf(stderr, "nonamed: %s: %s\n", NNCACHE,
|
|
ferror(fp) ? strerror(errno) : "Corrupt");
|
|
while (lru != nil) deallocate(extract_query(lru));
|
|
}
|
|
fclose(fp);
|
|
}
|
|
|
|
typedef int handler_t(void *data, int expired);
|
|
|
|
/* All actions are in the form of "jobs". */
|
|
typedef struct job {
|
|
struct job *next, **prev; /* To make a job queue. */
|
|
handler_t *handler; /* Function to handle this job. */
|
|
time_t timeout; /* Moment it times out. */
|
|
void *data; /* Data associated with the job. */
|
|
} job_t;
|
|
|
|
static job_t *queue; /* Main job queue. */
|
|
|
|
static void newjob(handler_t *handler, time_t timeout, void *data)
|
|
/* Create a new job with the given handler, timeout time and data. */
|
|
{
|
|
job_t *job, **prev;
|
|
|
|
job= allocate(nil, sizeof(*job));
|
|
job->handler= handler;
|
|
job->timeout= timeout;
|
|
job->data= data;
|
|
|
|
for (prev= &queue; *prev != nil; prev= &(*prev)->next) {
|
|
if (job->timeout < (*prev)->timeout) break;
|
|
}
|
|
job->next= *prev;
|
|
job->prev= prev;
|
|
*prev= job;
|
|
if (job->next != nil) job->next->prev= &job->next;
|
|
}
|
|
|
|
static int execjob(job_t *job, int expired)
|
|
/* Execute a job by calling the handler. Remove the job if it returns true,
|
|
* indicating that it is done. Expired is set if the job timed out. It is
|
|
* otherwise called to check for I/O.
|
|
*/
|
|
{
|
|
if ((*job->handler)(job->data, expired)) {
|
|
*job->prev= job->next;
|
|
if (job->next != nil) job->next->prev= job->prev;
|
|
deallocate(job);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void force_expire(handler_t *handler)
|
|
/* Force jobs to expire immediately, the named searcher for instance. */
|
|
{
|
|
job_t *job, **prev= &queue;
|
|
|
|
while ((job= *prev) != nil) {
|
|
if (job->handler == handler && job->timeout != IMMEDIATE) {
|
|
*prev= job->next;
|
|
if (job->next != nil) job->next->prev= prev;
|
|
newjob(job->handler, IMMEDIATE, job->data);
|
|
deallocate(job);
|
|
} else {
|
|
prev= &job->next;
|
|
}
|
|
}
|
|
}
|
|
|
|
static int nxdomain(u8_t *name)
|
|
/* True iff the two top level components in a name are repeated in the name,
|
|
* or if in-addr.arpa is found within a name. Such things happen often in a
|
|
* search for an already fully qualified local name. For instance:
|
|
* flotsam.cs.vu.nl.cs.vu.nl. (We don't want this at boot time.)
|
|
*/
|
|
{
|
|
u8_t *end, *top, *p;
|
|
size_t n;
|
|
|
|
end= namechr(name, 0);
|
|
top= end;
|
|
while (top > name && *--top != '.') {}
|
|
while (top > name && *--top != '.') {}
|
|
n= end - top;
|
|
p= top;
|
|
for (;;) {
|
|
if (p == name) return 0;
|
|
if (*--p == '.') {
|
|
if (namencmp(p, top, n) == 0 && p[n] == '.') return 1;
|
|
if (namencmp(p, ".in-addr.arpa.", 14) == 0) return 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
typedef struct id2id {
|
|
u16_t id; /* ID of old query. */
|
|
u16_t port; /* Reply port. */
|
|
ipaddr_t ip; /* Reply address. */
|
|
} id2id_t;
|
|
|
|
static id2id_t id2id[N_IDS];
|
|
static u16_t id_counter;
|
|
|
|
static u16_t new_id(u16_t in_id, u16_t in_port, ipaddr_t in_ip)
|
|
/* An incoming UDP query must be relabeled with a new ID before it can be
|
|
* send on to a real name daemon.
|
|
*/
|
|
{
|
|
id2id_t *idp;
|
|
u16_t id;
|
|
|
|
id= id_counter++;
|
|
idp= &id2id[id % N_IDS];
|
|
idp->id= in_id;
|
|
idp->port= in_port;
|
|
idp->ip= in_ip;
|
|
return htons(id);
|
|
}
|
|
|
|
static int old_id(u16_t id, u16_t *out_id, u16_t *out_port, ipaddr_t *out_ip)
|
|
/* Translate a reply id back to the id, port, and address used in the query.
|
|
* Return true if the translation is possible.
|
|
*/
|
|
{
|
|
id= ntohs(id);
|
|
if ((u16_t) (id_counter - id) > N_IDS) {
|
|
/* Too old. */
|
|
return 0;
|
|
} else {
|
|
/* We know this one. */
|
|
id2id_t *idp= &id2id[id % N_IDS];
|
|
|
|
if (idp->port == 0) return 0; /* Named is trying to fool us? */
|
|
*out_id= idp->id;
|
|
*out_port= idp->port;
|
|
*out_ip= idp->ip;
|
|
idp->port= 0;
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
/* IDs used to mark my own queries to name servers, must be new_id translated
|
|
* to make them unique "on the wire".
|
|
*/
|
|
#define ID_IPSELF HTONL(0) /* "I did it myself" address. */
|
|
#define ID_PROBE HTONS(0) /* Name server probe. */
|
|
#define ID_REFRESH HTONS(1) /* Query to refresh a cache entry. */
|
|
|
|
static char *tcp_device, *udp_device; /* TCP and UDP device names. */
|
|
static int udp_fd; /* To send or receive UDP packets. */
|
|
static asynchio_t asyn; /* For I/O in progress. */
|
|
static ipaddr_t my_ip; /* My IP address. */
|
|
static u16_t my_port, named_port; /* Port numbers, normally "domain". */
|
|
|
|
static ipaddr_t named[N_NAMEDS]; /* Addresses of all name servers. */
|
|
static unsigned n_nameds; /* Number of configured name daemons. */
|
|
static unsigned i_named; /* Index to current name server. */
|
|
static int expect; /* Set when we expect an answer. */
|
|
static int search_ct= -1; /* Named search count and state. */
|
|
static int dirty; /* True when new entry put in cache. */
|
|
|
|
#define current_named() (+named[i_named])
|
|
#define searching() (search_ct > 0)
|
|
#define start_searching() ((void) (search_ct= -1))
|
|
#define stop_searching() ((void) (search_ct= 0))
|
|
#define expecting() (+expect)
|
|
#define start_expecting() ((void) (expect= 1))
|
|
#define stop_expecting() ((void) (expect= 0))
|
|
|
|
static time_t filetime(const char *file)
|
|
/* Get the modified time of a file. */
|
|
{
|
|
struct stat st;
|
|
|
|
return stat(file, &st) == 0 ? st.st_mtime : 0;
|
|
}
|
|
|
|
static void init_config(ipaddr_t ifip)
|
|
/* Read name daemon list and other special stuff from the hosts file. */
|
|
{
|
|
struct hostent *he;
|
|
u32_t nip, hip;
|
|
static time_t hosts_time, dhcp_time;
|
|
time_t ht, dt;
|
|
|
|
/* See if anything really changed. */
|
|
if (((ifip ^ HTONL(0x7F000000)) & HTONL(0xFF000000)) == 0) ifip= my_ip;
|
|
ht= filetime(HOSTS);
|
|
dt= filetime(DHCPCACHE);
|
|
if (ifip == my_ip && ht == hosts_time && dt == dhcp_time) return;
|
|
my_ip= ifip;
|
|
hosts_time= ht;
|
|
dhcp_time= dt;
|
|
|
|
if (debug >= 2) {
|
|
printf("%s: I am nonamed %s at %s:%u\n",
|
|
nowgmt(), version, inet_ntoa(my_ip), ntohs(my_port));
|
|
}
|
|
|
|
httl= HTONL(HTTL);
|
|
stale= 0;
|
|
n_nameds= 0;
|
|
|
|
if (!single) {
|
|
sethostent(0);
|
|
while ((he= gethostent()) != nil) {
|
|
memcpy(&nip, he->h_addr, sizeof(u32_t));
|
|
hip= ntohl(nip);
|
|
if (namecmp(he->h_name, "%ttl") == 0) httl= nip;
|
|
if (namecmp(he->h_name, "%stale") == 0) stale= hip;
|
|
if (namecmp(he->h_name, "%memory") == 0) n_datamax= hip;
|
|
if (namecmp(he->h_name, "%nameserver") == 0) {
|
|
if (nip != my_ip || named_port != my_port) {
|
|
if (n_nameds < N_NAMEDS) named[n_nameds++]= nip;
|
|
}
|
|
}
|
|
}
|
|
endhostent();
|
|
}
|
|
|
|
if (n_nameds == 0) {
|
|
/* No name daemons found in the host file. What about DHCP? */
|
|
int fd;
|
|
dhcp_t d;
|
|
ssize_t r;
|
|
u8_t *data;
|
|
size_t len;
|
|
|
|
if ((fd= open(DHCPCACHE, O_RDONLY)) < 0) {
|
|
if (errno != ENOENT) fatal(DHCPCACHE);
|
|
} else {
|
|
while ((r= read(fd, &d, sizeof(d))) == sizeof(d)) {
|
|
if (d.yiaddr == my_ip) break;
|
|
}
|
|
if (r < 0) fatal(DHCPCACHE);
|
|
close(fd);
|
|
|
|
if (r == sizeof(d) && dhcp_gettag(&d, DHCP_TAG_DNS, &data, &len)) {
|
|
while (len >= sizeof(nip)) {
|
|
memcpy(&nip, data, sizeof(nip));
|
|
data += sizeof(nip);
|
|
len -= sizeof(nip);
|
|
if (nip != my_ip || named_port != my_port) {
|
|
if (n_nameds < N_NAMEDS) named[n_nameds++]= nip;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
i_named= 0;
|
|
}
|
|
|
|
static handler_t job_save_cache, job_read_udp, job_find_named, job_expect_named;
|
|
#if DO_TCP
|
|
static handler_t job_setup_listen, job_listen, job_setup_connect, job_connect;
|
|
static handler_t job_read_query, job_write_query;
|
|
static handler_t job_read_reply, job_write_reply;
|
|
#endif
|
|
|
|
static int query_hosts(u8_t *qname, unsigned type, dns_t *dp, size_t *pdlen)
|
|
/* Read the /etc/hosts file to try and answer an A or PTR query. Return
|
|
* true iff an answer can be found, with the answer copied to *dp.
|
|
*/
|
|
{
|
|
struct hostent *he;
|
|
int i, r;
|
|
dns_t dns;
|
|
u8_t *domain;
|
|
u8_t *cp;
|
|
u8_t name[MAXDNAME+1];
|
|
u8_t *dnvec[40];
|
|
unsigned ancount;
|
|
struct hostent localhost;
|
|
static char *noaliases[]= { nil };
|
|
static ipaddr_t localaddr= HTONL(0x7F000001L);
|
|
static char *localaddrlist[]= { (char *) &localaddr, nil };
|
|
|
|
if (single) return 0;
|
|
|
|
/* Assume we can answer. */
|
|
dns.hdr.dh_flag1= DHF_QR | DHF_AA;
|
|
dns.hdr.dh_flag2= DHF_RA;
|
|
dns.hdr.dh_qdcount= HTONS(1);
|
|
ancount= 0;
|
|
dns.hdr.dh_nscount= HTONS(0);
|
|
dns.hdr.dh_arcount= HTONS(0);
|
|
|
|
dnvec[0]= dns2oct(&dns);
|
|
dnvec[1]= nil;
|
|
cp= dns.data;
|
|
r= dn_comp(qname, cp, arraysize(dns.data), dnvec, arraylimit(dnvec));
|
|
if (r == -1) return 0;
|
|
cp += r;
|
|
pack16(cp, type);
|
|
cp += sizeof(u16_t);
|
|
pack16(cp, HTONS(C_IN));
|
|
cp += sizeof(u16_t);
|
|
|
|
/* Localhost is fixed to 127.0.0.1. */
|
|
localhost.h_name=
|
|
namencmp(qname, "localhost.", 10) == 0 ? (char *) qname : "localhost";
|
|
localhost.h_aliases= noaliases;
|
|
localhost.h_addr_list= localaddrlist;
|
|
he= &localhost;
|
|
|
|
sethostent(0);
|
|
do {
|
|
switch (type) {
|
|
case HTONS(T_A):
|
|
if (namecmp(qname, he->h_name) == 0) {
|
|
addA:
|
|
r= dn_comp((u8_t *) he->h_name, cp, arraylimit(dns.data) - cp,
|
|
dnvec, arraylimit(dnvec));
|
|
if (r == -1) return 0;
|
|
cp += r;
|
|
if (cp + 3 * sizeof(u16_t) + 2 * sizeof(u32_t)
|
|
> arraylimit(dns.data)) { r= -1; break; }
|
|
pack16(cp, HTONS(T_A));
|
|
cp += sizeof(u16_t);
|
|
pack16(cp, HTONS(C_IN));
|
|
cp += sizeof(u16_t);
|
|
pack32(cp, httl);
|
|
cp += sizeof(u32_t);
|
|
pack16(cp, HTONS(sizeof(u32_t)));
|
|
cp += sizeof(u16_t);
|
|
memcpy(cp, he->h_addr, sizeof(u32_t));
|
|
cp += sizeof(u32_t);
|
|
ancount++;
|
|
break;
|
|
}
|
|
/*FALL THROUGH*/
|
|
case HTONS(T_CNAME):
|
|
domain= namechr(he->h_name, '.');
|
|
for (i= 0; he->h_aliases[i] != nil; i++) {
|
|
namecpy(name, he->h_aliases[i]);
|
|
if (domain != nil && namechr(name, '.') == nil) {
|
|
namecat(name, domain);
|
|
}
|
|
if (namecmp(qname, name) == 0) {
|
|
r= dn_comp(name, cp, arraylimit(dns.data) - cp,
|
|
dnvec, arraylimit(dnvec));
|
|
if (r == -1) break;
|
|
cp += r;
|
|
if (cp + 3 * sizeof(u16_t)
|
|
+ 1 * sizeof(u32_t) > arraylimit(dns.data)) return 0;
|
|
pack16(cp, HTONS(T_CNAME));
|
|
cp += sizeof(u16_t);
|
|
pack16(cp, HTONS(C_IN));
|
|
cp += sizeof(u16_t);
|
|
pack32(cp, httl);
|
|
cp += sizeof(u32_t);
|
|
/* pack16(cp, htonl(RDLENGTH)) */
|
|
cp += sizeof(u16_t);
|
|
r= dn_comp((u8_t *) he->h_name, cp,
|
|
arraylimit(dns.data) - cp,
|
|
dnvec, arraylimit(dnvec));
|
|
if (r == -1) break;
|
|
pack16(cp - sizeof(u16_t), htons(r));
|
|
cp += r;
|
|
ancount++;
|
|
if (type == HTONS(T_A)) goto addA; /* really wants A */
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
case HTONS(T_PTR):
|
|
if (ancount > 0) break;
|
|
if (he->h_name[0] == '%') break;
|
|
sprintf((char *) name, "%d.%d.%d.%d.in-addr.arpa",
|
|
((u8_t *) he->h_addr)[3],
|
|
((u8_t *) he->h_addr)[2],
|
|
((u8_t *) he->h_addr)[1],
|
|
((u8_t *) he->h_addr)[0]);
|
|
if (namecmp(qname, name) == 0) {
|
|
r= dn_comp(name, cp, arraylimit(dns.data) - cp,
|
|
dnvec, arraylimit(dnvec));
|
|
if (r == -1) break;
|
|
cp += r;
|
|
if (cp + 3 * sizeof(u16_t) + 1 * sizeof(u32_t)
|
|
> arraylimit(dns.data)) { r= -1; break; }
|
|
pack16(cp, HTONS(T_PTR));
|
|
cp += sizeof(u16_t);
|
|
pack16(cp, HTONS(C_IN));
|
|
cp += sizeof(u16_t);
|
|
pack32(cp, httl);
|
|
cp += sizeof(u32_t);
|
|
/* pack16(cp, htonl(RDLENGTH)) */
|
|
cp += sizeof(u16_t);
|
|
r= dn_comp((u8_t *) he->h_name, cp,
|
|
arraylimit(dns.data) - cp, dnvec, arraylimit(dnvec));
|
|
if (r == -1) return 0;
|
|
pack16(cp - sizeof(u16_t), htons(r));
|
|
cp += r;
|
|
ancount++;
|
|
}
|
|
break;
|
|
}
|
|
} while (r != -1 && (he= gethostent()) != nil);
|
|
endhostent();
|
|
|
|
if (r == -1 || ancount == 0) return 0;
|
|
|
|
dns.hdr.dh_ancount= htons(ancount);
|
|
memcpy(dp, &dns, *pdlen= cp - dns2oct(&dns));
|
|
return 1;
|
|
}
|
|
|
|
static int query_chaos(u8_t *qname, unsigned type, dns_t *dp, size_t *pdlen)
|
|
/* Report my version. Can't let BIND take all the credit. :-) */
|
|
{
|
|
int i, n, r;
|
|
dns_t dns;
|
|
u8_t *cp;
|
|
u8_t *dnvec[40];
|
|
|
|
if (type != HTONS(T_TXT) || namecmp(qname, "version.bind") != 0) return 0;
|
|
|
|
dns.hdr.dh_flag1= DHF_QR | DHF_AA;
|
|
dns.hdr.dh_flag2= DHF_RA;
|
|
dns.hdr.dh_qdcount= HTONS(1);
|
|
dns.hdr.dh_ancount= HTONS(1);
|
|
dns.hdr.dh_nscount= HTONS(0);
|
|
dns.hdr.dh_arcount= htons(n_nameds);
|
|
|
|
dnvec[0]= dns2oct(&dns);
|
|
dnvec[1]= nil;
|
|
cp= dns.data;
|
|
r= dn_comp(qname, cp, arraysize(dns.data), dnvec, arraylimit(dnvec));
|
|
if (r == -1) return 0;
|
|
cp += r;
|
|
pack16(cp, type);
|
|
cp += sizeof(u16_t);
|
|
pack16(cp, HTONS(C_CHAOS));
|
|
cp += sizeof(u16_t);
|
|
|
|
r= dn_comp(qname, cp, arraylimit(dns.data) - cp, dnvec, arraylimit(dnvec));
|
|
if (r == -1) return 0;
|
|
cp += r;
|
|
pack16(cp, HTONS(T_TXT));
|
|
cp += sizeof(u16_t);
|
|
pack16(cp, HTONS(C_CHAOS));
|
|
cp += sizeof(u16_t);
|
|
pack32(cp, HTONL(0));
|
|
cp += sizeof(u32_t);
|
|
/* pack16(cp, htonl(RDLENGTH)) */
|
|
cp += sizeof(u16_t);
|
|
sprintf((char *) cp + 1, "nonamed %s at %s:%u",
|
|
version, inet_ntoa(my_ip), ntohs(my_port));
|
|
r= strlen((char *) cp + 1) + 1;
|
|
pack16(cp - sizeof(u16_t), htons(r));
|
|
*cp= r-1;
|
|
cp += r;
|
|
for (n= 0, i= i_named; n < n_nameds; n++, i= (i+1) % n_nameds) {
|
|
r= dn_comp((u8_t *) "%nameserver", cp, arraylimit(dns.data) - cp,
|
|
dnvec, arraylimit(dnvec));
|
|
if (r == -1) return 0;
|
|
cp += r;
|
|
if (cp + 3 * sizeof(u16_t)
|
|
+ 2 * sizeof(u32_t) > arraylimit(dns.data)) return 0;
|
|
pack16(cp, HTONS(T_A));
|
|
cp += sizeof(u16_t);
|
|
pack16(cp, HTONS(C_IN));
|
|
cp += sizeof(u16_t);
|
|
pack32(cp, HTONL(0));
|
|
cp += sizeof(u32_t);
|
|
pack16(cp, HTONS(sizeof(u32_t)));
|
|
cp += sizeof(u16_t);
|
|
memcpy(cp, &named[i], sizeof(u32_t));
|
|
cp += sizeof(u32_t);
|
|
}
|
|
|
|
memcpy(dp, &dns, *pdlen= cp - dns2oct(&dns));
|
|
return 1;
|
|
}
|
|
|
|
static void cache_reply(dns_t *dp, size_t dlen)
|
|
/* Store a DNS packet in the cache. */
|
|
{
|
|
int r;
|
|
query_t *qp, *less, *more;
|
|
unsigned usage;
|
|
u16_t type;
|
|
u8_t *cp;
|
|
u8_t name[MAXDNAME];
|
|
u32_t minttl;
|
|
|
|
if ((dp->hdr.dh_flag1 & (DHF_RD | DHF_TC)) != DHF_RD) return;
|
|
if (dp->hdr.dh_qdcount != HTONS(1)) return;
|
|
cp= dp->data;
|
|
r= dn_expand(dns2oct(dp), dns2oct(dp) + dlen, cp, name, MAXDNAME);
|
|
if (r == -1) return;
|
|
cp += r;
|
|
type= upack16(cp);
|
|
cp += sizeof(u16_t);
|
|
if (upack16(cp) != HTONS(C_IN)) return;
|
|
|
|
/* Delete old cached data, if any. Note where it is in the LRU. */
|
|
if ((qp= get_query(name, type)) != nil) {
|
|
less= qp->less;
|
|
more= qp->more;
|
|
usage= qp->usage;
|
|
deallocate(qp);
|
|
} else {
|
|
/* Not yet in the cache. */
|
|
less= mru;
|
|
more= nil;
|
|
usage= 1;
|
|
}
|
|
|
|
/* Determine minimum TTL. Discard if zero, never cache zero TTLs. */
|
|
if ((minttl= dns_ttl(dp, dlen, 0)) == 0) return;
|
|
|
|
/* Enter new reply in cache. */
|
|
qp= allocate(nil, query_allocsize(dlen));
|
|
qp->less= less;
|
|
qp->more= more;
|
|
qp->age= now;
|
|
qp->flags= 0;
|
|
qp->usage= usage;
|
|
qp->size= dlen;
|
|
memcpy(&qp->dns, dp, dlen);
|
|
qp->stale= qp->age + minttl;
|
|
insert_query(qp);
|
|
if (debug >= 1) printf("Answer cached\n");
|
|
|
|
/* Save the cache soon. */
|
|
if (!dirty) {
|
|
dirty= 1;
|
|
newjob(job_save_cache, now + LONG_TIMEOUT, nil);
|
|
}
|
|
}
|
|
|
|
static int job_save_cache(void *data, int expired)
|
|
/* Some time after the cache is changed it is written back to disk. */
|
|
{
|
|
if (!expired) return 0;
|
|
cache2file();
|
|
dirty= 0;
|
|
}
|
|
|
|
static int compose_reply(dns_t *dp, size_t *pdlen)
|
|
/* Try to compose a reply to a request in *dp using the hosts file or
|
|
* cached data. Return answer in *dp with its size in *pdlen. Return true
|
|
* iff an answer is given.
|
|
*/
|
|
{
|
|
size_t dlen= *pdlen;
|
|
int r, rd;
|
|
query_t *qp;
|
|
unsigned id, type, class;
|
|
u8_t *cp;
|
|
u8_t name[MAXDNAME];
|
|
|
|
cp= dp->data;
|
|
r= dn_expand(dns2oct(dp), dns2oct(dp) + dlen, cp, name, MAXDNAME);
|
|
if (r != -1) {
|
|
cp += r;
|
|
if (cp + 2 * sizeof(u16_t) > dns2oct(dp) + dlen) {
|
|
r= -1;
|
|
} else {
|
|
type= upack16(cp);
|
|
cp += sizeof(u16_t);
|
|
class= upack16(cp);
|
|
cp += sizeof(u16_t);
|
|
}
|
|
}
|
|
|
|
/* Remember ID and RD. */
|
|
id= dp->hdr.dh_id;
|
|
rd= dp->hdr.dh_flag1 & DHF_RD;
|
|
|
|
if (r == -1) {
|
|
/* Malformed query, reply "FORMERR". */
|
|
dp->hdr.dh_flag1 &= ~(DHF_TC);
|
|
dp->hdr.dh_flag1 |= DHF_QR | DHF_AA;
|
|
dp->hdr.dh_flag2 &= ~(DHF_UNUSED | DHF_RCODE);
|
|
dp->hdr.dh_flag2 |= DHF_RA | FORMERR;
|
|
} else
|
|
if (class == HTONS(C_IN) && query_hosts(name, type, dp, pdlen)) {
|
|
/* Answer to this query is in the hosts file. */
|
|
dlen= *pdlen;
|
|
} else
|
|
if (class == HTONS(C_IN) && (qp= get_query(name, type)) != nil) {
|
|
/* Answer to this query is present in the cache. */
|
|
memcpy(dp, &qp->dns, dlen= qp->size);
|
|
dp->hdr.dh_flag1 &= ~DHF_AA;
|
|
(void) dns_ttl(dp, dlen, now - qp->age);
|
|
if (rd) {
|
|
if (qp->stale <= now) {
|
|
qp->flags |= QF_REFRESH;
|
|
q_refresh= 1;
|
|
}
|
|
qp->usage++;
|
|
}
|
|
put_query(qp);
|
|
} else
|
|
if (class == HTONS(C_CHAOS) && query_chaos(name, type, dp, pdlen)) {
|
|
/* Return our version numbers. */
|
|
dlen= *pdlen;
|
|
} else
|
|
if (n_nameds == 0 || nxdomain(name)) {
|
|
/* No real name daemon present, or this name has a repeated top level
|
|
* domain sequence. Reply "no such domain".
|
|
*/
|
|
dp->hdr.dh_flag1 &= ~(DHF_TC);
|
|
dp->hdr.dh_flag1 |= DHF_QR | DHF_AA;
|
|
dp->hdr.dh_flag2 &= ~(DHF_UNUSED | DHF_RCODE);
|
|
dp->hdr.dh_flag2 |= DHF_RA | NXDOMAIN;
|
|
} else
|
|
if (!rd) {
|
|
/* "Recursion Desired" is off, so don't bother to relay. */
|
|
dp->hdr.dh_flag1 &= ~(DHF_TC);
|
|
dp->hdr.dh_flag1 |= DHF_QR;
|
|
dp->hdr.dh_flag2 &= ~(DHF_UNUSED | DHF_RCODE);
|
|
dp->hdr.dh_flag2 |= DHF_RA | NOERROR;
|
|
} else {
|
|
/* Caller needs to consult with a real name daemon. */
|
|
return 0;
|
|
}
|
|
|
|
/* Copy ID and RD back to answer. */
|
|
dp->hdr.dh_id= id;
|
|
dp->hdr.dh_flag1 &= ~DHF_RD;
|
|
dp->hdr.dh_flag1 |= rd;
|
|
*pdlen= dlen;
|
|
return 1;
|
|
}
|
|
|
|
typedef struct udp_dns { /* One DNS packet over UDP. */
|
|
udp_io_hdr_t hdr; /* UDP header (source/destination). */
|
|
dns_t dns; /* DNS packet. */
|
|
} udp_dns_t;
|
|
|
|
static void refresh_cache(void)
|
|
/* Find a stale entry in the cache that was used to answer a query, and send
|
|
* a request to a name server that should refresh this entry.
|
|
*/
|
|
{
|
|
query_t *qp;
|
|
unsigned type;
|
|
int r;
|
|
u8_t *cp;
|
|
size_t dlen, ulen;
|
|
u8_t qname[MAXDNAME+1];
|
|
u8_t *dnvec[40];
|
|
udp_dns_t udp;
|
|
|
|
if (!q_refresh) return;
|
|
for (qp= lru; qp != nil; qp= qp->more) {
|
|
if ((qp->flags & QF_REFRESH) && qp->stale > now - stale) break;
|
|
}
|
|
if (qp == nil) {
|
|
q_refresh= 0;
|
|
return;
|
|
}
|
|
|
|
/* Found one to refresh. */
|
|
qp->flags &= ~QF_REFRESH;
|
|
r= dn_expand(dns2oct(&qp->dns), dns2oct(&qp->dns) + qp->size,
|
|
qp->dns.data, qname, MAXDNAME);
|
|
if (r == -1) return;
|
|
type= upack16(qp->dns.data+r);
|
|
|
|
dnvec[0]= dns2oct(&udp.dns);
|
|
dnvec[1]= nil;
|
|
cp= udp.dns.data;
|
|
r= dn_comp(qname, cp, arraysize(udp.dns.data), dnvec, arraylimit(dnvec));
|
|
if (r == -1) return;
|
|
cp += r;
|
|
pack16(cp, type);
|
|
cp += sizeof(u16_t);
|
|
pack16(cp, HTONS(C_IN));
|
|
cp += sizeof(u16_t);
|
|
dlen= cp - dns2oct(&udp.dns);
|
|
|
|
udp.dns.hdr.dh_id= new_id(ID_REFRESH, my_port, ID_IPSELF);
|
|
udp.dns.hdr.dh_flag1= DHF_RD;
|
|
udp.dns.hdr.dh_flag2= 0;
|
|
udp.dns.hdr.dh_qdcount= HTONS(1);
|
|
udp.dns.hdr.dh_ancount= HTONS(0);
|
|
udp.dns.hdr.dh_nscount= HTONS(0);
|
|
udp.dns.hdr.dh_arcount= HTONS(0);
|
|
|
|
udp.hdr.uih_dst_addr= current_named();
|
|
udp.hdr.uih_dst_port= named_port;
|
|
udp.hdr.uih_ip_opt_len= 0;
|
|
udp.hdr.uih_data_len= dlen;
|
|
|
|
if (debug >= 1) {
|
|
printf("Refresh to %s:%u:\n",
|
|
inet_ntoa(current_named()), ntohs(named_port));
|
|
dns_tell(0, &udp.dns, dlen);
|
|
}
|
|
ulen= offsetof(udp_dns_t, dns) + dlen;
|
|
if (write(udp_fd, &udp, ulen) < 0) fatal(udp_device);
|
|
}
|
|
|
|
static int job_read_udp(void *data, int expired)
|
|
/* Read UDP queries and replies. */
|
|
{
|
|
size_t ulen, dlen;
|
|
static udp_dns_t udp;
|
|
u16_t id, port;
|
|
ipaddr_t ip;
|
|
time_t dtime;
|
|
|
|
assert(!expired);
|
|
|
|
/* Try to read a packet. */
|
|
ulen= asyn_read(&asyn, udp_fd, &udp, sizeof(udp));
|
|
dlen= ulen - offsetof(udp_dns_t, dns);
|
|
|
|
if (ulen == -1) {
|
|
if (errno == EINPROGRESS && !expired) return 0;
|
|
if (errno == EIO) fatal(udp_device);
|
|
|
|
if (debug >= 2) {
|
|
printf("%s: UDP read: %s\n", nowgmt(), strerror(errno));
|
|
}
|
|
} else {
|
|
if (debug >= 2) {
|
|
printf("%s: UDP read, %d bytes\n", nowgmt(), (int) ulen);
|
|
}
|
|
}
|
|
|
|
/* Restart this job no matter what. */
|
|
newjob(job_read_udp, NEVER, nil);
|
|
|
|
if (ulen < (ssize_t) (sizeof(udp_io_hdr_t) + sizeof(dns_hdr_t))) return 1;
|
|
|
|
if (debug >= 1) {
|
|
printf("%s:%u UDP ", inet_ntoa(udp.hdr.uih_src_addr),
|
|
ntohs(udp.hdr.uih_src_port));
|
|
dns_tell(0, &udp.dns, dlen);
|
|
}
|
|
|
|
/* Check, and if necessary reinitialize my configuration. */
|
|
init_config(udp.hdr.uih_dst_addr);
|
|
|
|
if (udp.dns.hdr.dh_flag1 & DHF_QR) {
|
|
/* This is a remote named reply, not a query. */
|
|
|
|
/* Response to a query previously relayed? */
|
|
if (!old_id(udp.dns.hdr.dh_id, &id, &port, &ip)) return 1;
|
|
|
|
if (ip == ID_IPSELF && id == ID_PROBE) {
|
|
if (searching()) {
|
|
/* We have found a name server! */
|
|
int i;
|
|
|
|
/* In my list? */
|
|
for (i= 0; i < n_nameds; i++) {
|
|
if (named[i] == udp.hdr.uih_src_addr) {
|
|
i_named= i;
|
|
if (debug >= 1) {
|
|
printf("Current named = %s\n",
|
|
inet_ntoa(current_named()));
|
|
}
|
|
stop_searching();
|
|
force_expire(job_find_named);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* We got an answer, so stop worrying. */
|
|
if (expecting()) {
|
|
stop_expecting();
|
|
force_expire(job_expect_named);
|
|
}
|
|
|
|
/* Put the information in the cache. */
|
|
cache_reply(&udp.dns, dlen);
|
|
|
|
/* Refresh a cached entry that was used when stale. */
|
|
refresh_cache();
|
|
|
|
/* Discard reply to myself. */
|
|
if (ip == ID_IPSELF) return 1;
|
|
|
|
/* Send the reply to the process that asked for it. */
|
|
udp.dns.hdr.dh_id= id;
|
|
udp.hdr.uih_dst_addr= ip;
|
|
udp.hdr.uih_dst_port= port;
|
|
if (debug >= 1) printf("To client %s:%u\n", inet_ntoa(ip), ntohs(port));
|
|
} else {
|
|
/* A query. */
|
|
if (udp.dns.hdr.dh_qdcount != HTONS(1)) return 1;
|
|
|
|
/* Try to compose a reply from local data. */
|
|
if (compose_reply(&udp.dns, &dlen)) {
|
|
udp.hdr.uih_dst_addr= udp.hdr.uih_src_addr;
|
|
udp.hdr.uih_dst_port= udp.hdr.uih_src_port;
|
|
udp.hdr.uih_ip_opt_len= 0;
|
|
udp.hdr.uih_data_len= dlen;
|
|
ulen= offsetof(udp_dns_t, dns) + dlen;
|
|
|
|
/* Send an UDP DNS reply. */
|
|
if (debug >= 1) {
|
|
printf("%s:%u UDP ", inet_ntoa(udp.hdr.uih_dst_addr),
|
|
ntohs(udp.hdr.uih_dst_port));
|
|
dns_tell(0, &udp.dns, dlen);
|
|
}
|
|
} else {
|
|
/* Let a real name daemon handle the query. */
|
|
udp.dns.hdr.dh_id= new_id(udp.dns.hdr.dh_id,
|
|
udp.hdr.uih_src_port, udp.hdr.uih_src_addr);
|
|
udp.hdr.uih_dst_addr= current_named();
|
|
udp.hdr.uih_dst_port= named_port;
|
|
if (!expecting()) {
|
|
start_expecting();
|
|
newjob(job_expect_named, now + MEDIUM_TIMEOUT, nil);
|
|
}
|
|
if (debug >= 1) {
|
|
printf("To named %s:%u\n",
|
|
inet_ntoa(current_named()), ntohs(named_port));
|
|
}
|
|
}
|
|
}
|
|
if (write(udp_fd, &udp, ulen) < 0) fatal(udp_device);
|
|
return 1;
|
|
}
|
|
|
|
#if DO_TCP
|
|
|
|
typedef struct data_cl { /* Data for connect or listen jobs. */
|
|
int fd; /* Open TCP channel. */
|
|
int dn_fd; /* TCP channel to the name daemon. */
|
|
int retry; /* Retrying a connect? */
|
|
nwio_tcpcl_t tcpcl; /* Flags. */
|
|
} data_cl_t;
|
|
|
|
typedef struct data_rw { /* Data for TCP read or write jobs. */
|
|
int r_fd; /* Read from this TCP channel. */
|
|
int w_fd; /* And write to this TCP channel. */
|
|
struct data_rw *rev; /* Optional reverse TCP channel. */
|
|
u8_t *buf; /* Buffer for bytes to transfer. */
|
|
ssize_t offset; /* Offset in buf to r/w at. */
|
|
size_t size; /* Size of buf. */
|
|
} data_rw_t;
|
|
|
|
static int job_setup_listen(void *data, int expired)
|
|
/* Set up a listening channel for TCP DNS queries. */
|
|
{
|
|
data_cl_t *data_cl= data;
|
|
nwio_tcpconf_t tcpconf;
|
|
nwio_tcpopt_t tcpopt;
|
|
int fd;
|
|
|
|
if (!expired) return 0;
|
|
if (debug >= 2) printf("%s: Setup listen\n", nowgmt());
|
|
|
|
if (data_cl == nil) {
|
|
if ((fd= open(tcp_device, O_RDWR)) < 0) {
|
|
if (errno != EMFILE) report(tcp_device);
|
|
newjob(job_setup_listen, now + SHORT_TIMEOUT, nil);
|
|
return 1;
|
|
}
|
|
|
|
tcpconf.nwtc_flags= NWTC_SHARED | NWTC_LP_SET | NWTC_UNSET_RA
|
|
| NWTC_UNSET_RP;
|
|
tcpconf.nwtc_locport= my_port;
|
|
if (ioctl(fd, NWIOSTCPCONF, &tcpconf) == -1) fatal(tcp_device);
|
|
|
|
tcpopt.nwto_flags= NWTO_DEL_RST;
|
|
if (ioctl(fd, NWIOSTCPOPT, &tcpopt) == -1) fatal(tcp_device);
|
|
|
|
data_cl= allocate(nil, sizeof(*data_cl));
|
|
data_cl->fd= fd;
|
|
data_cl->tcpcl.nwtcl_flags= 0;
|
|
}
|
|
/* And listen. */
|
|
newjob(job_listen, NEVER, data_cl);
|
|
return 1;
|
|
}
|
|
|
|
static int job_listen(void *data, int expired)
|
|
/* A connection on the TCP DNS query channel. */
|
|
{
|
|
data_cl_t *data_cl= data;
|
|
|
|
/* Wait for a client. */
|
|
if (asyn_ioctl(&asyn, data_cl->fd, NWIOTCPLISTEN, &data_cl->tcpcl) < 0) {
|
|
if (errno == EINPROGRESS) return 0;
|
|
report(tcp_device);
|
|
|
|
/* Try again after a short time. */
|
|
newjob(job_setup_listen, now + SHORT_TIMEOUT, data_cl);
|
|
return 1;
|
|
}
|
|
if (debug >= 2) printf("%s: Listen\n", nowgmt());
|
|
|
|
/* Immediately resume listening. */
|
|
newjob(job_setup_listen, IMMEDIATE, nil);
|
|
|
|
/* Set up a connect to the real name daemon. */
|
|
data_cl->retry= 0;
|
|
newjob(job_setup_connect, IMMEDIATE, data_cl);
|
|
return 1;
|
|
}
|
|
|
|
static void start_relay(int fd, int dn_fd)
|
|
/* Start one or two read jobs after job_setup_connect() or job_connect(). */
|
|
{
|
|
data_rw_t *query; /* Client to DNS daemon relay. */
|
|
data_rw_t *reply; /* DNS daemon to client relay. */
|
|
|
|
query= allocate(nil, sizeof(*query));
|
|
query->r_fd= fd;
|
|
query->buf= allocate(nil, sizeof(u16_t));
|
|
query->offset= 0;
|
|
query->size= sizeof(u16_t);
|
|
if (dn_fd == NO_FD) {
|
|
/* Answer mode. */
|
|
query->w_fd= fd;
|
|
query->rev= nil;
|
|
} else {
|
|
/* Relay mode. */
|
|
reply= allocate(nil, sizeof(*reply));
|
|
reply->r_fd= dn_fd;
|
|
reply->w_fd= fd;
|
|
reply->buf= allocate(nil, sizeof(u16_t));
|
|
reply->offset= 0;
|
|
reply->size= sizeof(u16_t);
|
|
reply->rev= query;
|
|
query->w_fd= dn_fd;
|
|
query->rev= reply;
|
|
newjob(job_read_reply, now + LONG_TIMEOUT, reply);
|
|
}
|
|
newjob(job_read_query, now + LONG_TIMEOUT, query);
|
|
}
|
|
|
|
static void close_relay(data_rw_t *data_rw)
|
|
/* Close a relay channel. */
|
|
{
|
|
if (data_rw->rev != nil) {
|
|
/* Other end still active, signal EOF. */
|
|
(void) ioctl(data_rw->w_fd, NWIOTCPSHUTDOWN, nil);
|
|
data_rw->rev->rev= nil;
|
|
} else {
|
|
/* Close both ends down. */
|
|
asyn_close(&asyn, data_rw->r_fd);
|
|
close(data_rw->r_fd);
|
|
if (data_rw->w_fd != data_rw->r_fd) {
|
|
asyn_close(&asyn, data_rw->w_fd);
|
|
close(data_rw->w_fd);
|
|
}
|
|
}
|
|
deallocate(data_rw->buf);
|
|
deallocate(data_rw);
|
|
}
|
|
|
|
static int job_setup_connect(void *data, int expired)
|
|
/* Set up a connect for a TCP channel to the real name daemon. */
|
|
{
|
|
nwio_tcpconf_t tcpconf;
|
|
int dn_fd;
|
|
data_cl_t *data_cl= data;
|
|
|
|
if (!expired) return 0;
|
|
if (debug >= 2) printf("%s: Setup connect\n", nowgmt());
|
|
|
|
if (n_nameds == 0) {
|
|
/* No name daemons to relay to, answer myself. */
|
|
start_relay(data_cl->fd, NO_FD);
|
|
deallocate(data_cl);
|
|
return 1;
|
|
}
|
|
|
|
if ((dn_fd= open(tcp_device, O_RDWR)) < 0) {
|
|
if (errno != EMFILE) report(tcp_device);
|
|
if (++data_cl->retry < 5) {
|
|
/* Retry. */
|
|
newjob(job_setup_connect, now + SHORT_TIMEOUT, data_cl);
|
|
} else {
|
|
/* Reply myself (bound to fail). */
|
|
start_relay(data_cl->fd, NO_FD);
|
|
deallocate(data_cl);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
tcpconf.nwtc_flags= NWTC_LP_SEL | NWTC_SET_RA | NWTC_SET_RP;
|
|
tcpconf.nwtc_remaddr= current_named();
|
|
tcpconf.nwtc_remport= named_port;
|
|
if (ioctl(dn_fd, NWIOSTCPCONF, &tcpconf) == -1) fatal(tcp_device);
|
|
|
|
/* And connect. */
|
|
data_cl->dn_fd= dn_fd;
|
|
data_cl->tcpcl.nwtcl_flags= 0;
|
|
newjob(job_connect, NEVER, data_cl);
|
|
return 1;
|
|
}
|
|
|
|
static int job_connect(void *data, int expired)
|
|
/* Connect to a TCP DNS query channel. */
|
|
{
|
|
data_cl_t *data_cl= data;
|
|
|
|
/* Try to connect. */
|
|
if (asyn_ioctl(&asyn, data_cl->dn_fd, NWIOTCPCONN, &data_cl->tcpcl) < 0) {
|
|
if (errno == EINPROGRESS) return 0;
|
|
if (errno == EIO) fatal(tcp_device);
|
|
|
|
/* Connection refused. */
|
|
if (debug >= 2) printf("%s: Connect: %s\n", nowgmt(), strerror(errno));
|
|
asyn_close(&asyn, data_cl->dn_fd);
|
|
close(data_cl->dn_fd);
|
|
data_cl->dn_fd= NO_FD;
|
|
if (++data_cl->retry < 5) {
|
|
/* Search a new name daemon. */
|
|
if (!searching()) {
|
|
start_searching();
|
|
force_expire(job_find_named);
|
|
}
|
|
newjob(job_setup_connect, NEVER, data_cl);
|
|
return 1;
|
|
}
|
|
/* Reply with a failure eventually. */
|
|
}
|
|
if (debug >= 2) printf("%s: Connect\n", nowgmt());
|
|
|
|
/* Read the query from the user, send on to the name daemon, etc. */
|
|
start_relay(data_cl->fd, data_cl->dn_fd);
|
|
deallocate(data_cl);
|
|
return 1;
|
|
}
|
|
|
|
static void tcp_dns_tell(int fd, u8_t *buf)
|
|
/* Tell about a DNS packet on a TCP channel. */
|
|
{
|
|
nwio_tcpconf_t tcpconf;
|
|
|
|
if (ioctl(fd, NWIOGTCPCONF, &tcpconf) < 0) {
|
|
printf("??\?:?? TCP ");
|
|
} else {
|
|
printf("%s:%u TCP ", inet_ntoa(tcpconf.nwtc_remaddr),
|
|
ntohs(tcpconf.nwtc_remport));
|
|
}
|
|
dns_tell(0, oct2dns(buf + sizeof(u16_t)), ntohs(upack16(buf)));
|
|
}
|
|
|
|
static int job_read_query(void *data, int expired)
|
|
/* Read TCP queries from the client. */
|
|
{
|
|
data_rw_t *data_rw= data;
|
|
ssize_t count;
|
|
|
|
/* Try to read count bytes. */
|
|
count= asyn_read(&asyn, data_rw->r_fd,
|
|
data_rw->buf + data_rw->offset,
|
|
data_rw->size - data_rw->offset);
|
|
|
|
if (count < 0) {
|
|
if (errno == EINPROGRESS && !expired) return 0;
|
|
if (errno == EIO) fatal(tcp_device);
|
|
|
|
/* Remote end is late, or an error occurred. */
|
|
if (debug >= 2) {
|
|
printf("%s: TCP read query: %s\n", nowgmt(), strerror(errno));
|
|
}
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
|
|
if (debug >= 2) {
|
|
printf("%s: TCP read query, %d/%u bytes\n",
|
|
nowgmt(), data_rw->offset + count, data_rw->size);
|
|
}
|
|
if (count == 0) {
|
|
/* EOF. */
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
data_rw->offset += count;
|
|
if (data_rw->offset == data_rw->size) {
|
|
data_rw->size= sizeof(u16_t) + ntohs(upack16(data_rw->buf));
|
|
if (data_rw->size < sizeof(u16_t)) {
|
|
/* Malformed. */
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
if (data_rw->offset < data_rw->size) {
|
|
/* Query not complete, read more. */
|
|
data_rw->buf= allocate(data_rw->buf, data_rw->size);
|
|
newjob(job_read_query, now + LONG_TIMEOUT, data_rw);
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
if (data_rw->size < sizeof(u16_t) + sizeof(dns_hdr_t)) {
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
if (debug >= 1) tcp_dns_tell(data_rw->r_fd, data_rw->buf);
|
|
|
|
/* Relay or reply. */
|
|
if (data_rw->w_fd != data_rw->r_fd) {
|
|
/* We have a real name daemon to do the work. */
|
|
data_rw->offset= 0;
|
|
newjob(job_write_query, now + LONG_TIMEOUT, data_rw);
|
|
} else {
|
|
/* No real name daemons or none reachable, so use the hosts file. */
|
|
dns_t *dp;
|
|
size_t dlen;
|
|
|
|
if (data_rw->size < sizeof(u16_t) + PACKETSZ) {
|
|
data_rw->buf= allocate(data_rw->buf, sizeof(u16_t) + PACKETSZ);
|
|
}
|
|
|
|
/* Build a reply packet. */
|
|
dp= oct2dns(data_rw->buf + sizeof(u16_t));
|
|
dlen= data_rw->size - sizeof(u16_t);
|
|
if (!compose_reply(dp, &dlen)) {
|
|
/* We're told to ask a name daemon, but that won't work. */
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
|
|
/* Start a reply write. */
|
|
pack16(data_rw->buf, htons(dlen));
|
|
data_rw->size= sizeof(u16_t) + dlen;
|
|
data_rw->buf= allocate(data_rw->buf, data_rw->size);
|
|
data_rw->offset= 0;
|
|
newjob(job_write_reply, now + LONG_TIMEOUT, data_rw);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static int job_write_query(void *data, int expired)
|
|
/* Relay a TCP query to the name daemon. */
|
|
{
|
|
data_rw_t *data_rw= data;
|
|
ssize_t count;
|
|
|
|
/* Try to write count bytes to the name daemon. */
|
|
count= asyn_write(&asyn, data_rw->w_fd,
|
|
data_rw->buf + data_rw->offset,
|
|
data_rw->size - data_rw->offset);
|
|
|
|
if (count <= 0) {
|
|
if (errno == EINPROGRESS && !expired) return 0;
|
|
if (errno == EIO) fatal(tcp_device);
|
|
|
|
/* A write expired or failed (usually a broken connection.) */
|
|
if (debug >= 2) {
|
|
printf("%s: TCP write query: %s\n", nowgmt(), strerror(errno));
|
|
}
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
|
|
if (debug >= 2) {
|
|
printf("%s: TCP write query, %d/%u bytes\n",
|
|
nowgmt(), data_rw->offset + count, data_rw->size);
|
|
}
|
|
data_rw->offset += count;
|
|
if (data_rw->offset < data_rw->size) {
|
|
/* Partial write, continue. */
|
|
newjob(job_write_query, now + LONG_TIMEOUT, data_rw);
|
|
return 1;
|
|
}
|
|
if (debug >= 1) tcp_dns_tell(data_rw->w_fd, data_rw->buf);
|
|
|
|
/* Query fully send on, go read more queries. */
|
|
data_rw->offset= 0;
|
|
data_rw->size= sizeof(u16_t);
|
|
newjob(job_read_query, now + LONG_TIMEOUT, data_rw);
|
|
return 1;
|
|
}
|
|
|
|
static int job_read_reply(void *data, int expired)
|
|
/* Read a TCP reply from the real name daemon. */
|
|
{
|
|
data_rw_t *data_rw= data;
|
|
ssize_t count;
|
|
|
|
/* Try to read count bytes. */
|
|
count= asyn_read(&asyn, data_rw->r_fd,
|
|
data_rw->buf + data_rw->offset,
|
|
data_rw->size - data_rw->offset);
|
|
|
|
if (count < 0) {
|
|
if (errno == EINPROGRESS && !expired) return 0;
|
|
if (errno == EIO) fatal(tcp_device);
|
|
|
|
/* Remote end is late, or an error occurred. */
|
|
if (debug >= 2) {
|
|
printf("%s: TCP read reply: %s\n", nowgmt(), strerror(errno));
|
|
}
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
|
|
if (debug >= 2) {
|
|
printf("%s: TCP read reply, %d/%u bytes\n",
|
|
nowgmt(), data_rw->offset + count, data_rw->size);
|
|
}
|
|
if (count == 0) {
|
|
/* EOF. */
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
data_rw->offset += count;
|
|
if (data_rw->offset == data_rw->size) {
|
|
data_rw->size= sizeof(u16_t) + ntohs(upack16(data_rw->buf));
|
|
if (data_rw->size < sizeof(u16_t)) {
|
|
/* Malformed. */
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
if (data_rw->offset < data_rw->size) {
|
|
/* Reply not complete, read more. */
|
|
data_rw->buf= allocate(data_rw->buf, data_rw->size);
|
|
newjob(job_read_reply, now + LONG_TIMEOUT, data_rw);
|
|
return 1;
|
|
}
|
|
}
|
|
if (debug >= 1) tcp_dns_tell(data_rw->r_fd, data_rw->buf);
|
|
|
|
/* Reply fully read, send it on. */
|
|
data_rw->offset= 0;
|
|
newjob(job_write_reply, now + LONG_TIMEOUT, data_rw);
|
|
return 1;
|
|
}
|
|
|
|
static int job_write_reply(void *data, int expired)
|
|
/* Send a TCP reply to the client. */
|
|
{
|
|
data_rw_t *data_rw= data;
|
|
ssize_t count;
|
|
|
|
/* Try to write count bytes to the client. */
|
|
count= asyn_write(&asyn, data_rw->w_fd,
|
|
data_rw->buf + data_rw->offset,
|
|
data_rw->size - data_rw->offset);
|
|
|
|
if (count <= 0) {
|
|
if (errno == EINPROGRESS && !expired) return 0;
|
|
if (errno == EIO) fatal(tcp_device);
|
|
|
|
/* A write expired or failed (usually a broken connection.) */
|
|
if (debug >= 2) {
|
|
printf("%s: TCP write reply: %s\n", nowgmt(), strerror(errno));
|
|
}
|
|
close_relay(data_rw);
|
|
return 1;
|
|
}
|
|
|
|
if (debug >= 2) {
|
|
printf("%s: TCP write reply, %d/%u bytes\n",
|
|
nowgmt(), data_rw->offset + count, data_rw->size);
|
|
}
|
|
data_rw->offset += count;
|
|
if (data_rw->offset < data_rw->size) {
|
|
/* Partial write, continue. */
|
|
newjob(job_write_reply, now + LONG_TIMEOUT, data_rw);
|
|
return 1;
|
|
}
|
|
if (debug >= 1) tcp_dns_tell(data_rw->w_fd, data_rw->buf);
|
|
|
|
/* Reply fully send on, go read more replies (or queries). */
|
|
data_rw->offset= 0;
|
|
data_rw->size= sizeof(u16_t);
|
|
newjob(data_rw->w_fd != data_rw->r_fd ? job_read_reply : job_read_query,
|
|
now + LONG_TIMEOUT, data_rw);
|
|
return 1;
|
|
}
|
|
#else /* !DO_TCP */
|
|
|
|
static int job_dummy(void *data, int expired)
|
|
{
|
|
return 1;
|
|
}
|
|
#define job_setup_listen job_dummy
|
|
#define job_setup_connect job_dummy
|
|
#endif /* !DO_TCP */
|
|
|
|
static void named_probe(ipaddr_t ip)
|
|
/* Send a probe to a name daemon, like 'host -r -t ns . <ip>'. */
|
|
{
|
|
udp_dns_t udp;
|
|
# define dlen (offsetof(dns_t, data) + 5)
|
|
# define ulen (offsetof(udp_dns_t, dns) + dlen)
|
|
|
|
/* Send a simple DNS query that all name servers can answer easily:
|
|
* "What are the name servers for the root domain?"
|
|
*/
|
|
udp.dns.hdr.dh_id= new_id(ID_PROBE, my_port, ID_IPSELF);
|
|
udp.dns.hdr.dh_flag1= 0;
|
|
udp.dns.hdr.dh_flag2= 0;
|
|
udp.dns.hdr.dh_qdcount= HTONS(1);
|
|
udp.dns.hdr.dh_ancount= HTONS(0);
|
|
udp.dns.hdr.dh_nscount= HTONS(0);
|
|
udp.dns.hdr.dh_arcount= HTONS(0);
|
|
|
|
udp.dns.data[0] = 0; /* Null name. */
|
|
pack16(udp.dns.data+1, HTONS(T_NS));
|
|
pack16(udp.dns.data+3, HTONS(C_IN));
|
|
if (debug >= 1) {
|
|
printf("PROBE %s ", inet_ntoa(ip));
|
|
dns_tell(0, &udp.dns, dlen);
|
|
}
|
|
|
|
udp.hdr.uih_dst_addr= ip;
|
|
udp.hdr.uih_dst_port= named_port;
|
|
udp.hdr.uih_ip_opt_len= 0;
|
|
udp.hdr.uih_data_len= dlen;
|
|
|
|
if (write(udp_fd, &udp, ulen) < 0) fatal(udp_device);
|
|
#undef dlen
|
|
#undef ulen
|
|
}
|
|
|
|
static int job_find_named(void *data, int expired)
|
|
/* Look for a real name daemon to answer real DNS queries. */
|
|
{
|
|
if (!expired) return 0;
|
|
if (debug >= 2) printf("%s: Find named\n", nowgmt());
|
|
|
|
/* New search? */
|
|
if (search_ct < 0) {
|
|
search_ct= n_nameds;
|
|
i_named= -1;
|
|
}
|
|
|
|
if (--search_ct < 0) {
|
|
/* Forced end of search (named response!), or end of search with
|
|
* nothing found. Search again after a long time.
|
|
*/
|
|
newjob(job_find_named,
|
|
(stale > 0 || i_named > 0) ? now + LONG_TIMEOUT : NEVER, nil);
|
|
force_expire(job_setup_connect);
|
|
return 1;
|
|
}
|
|
|
|
/* Send a named probe. */
|
|
i_named= (i_named+1) % n_nameds;
|
|
named_probe(current_named());
|
|
|
|
/* Schedule the next call. */
|
|
newjob(job_find_named, now + SHORT_TIMEOUT, nil);
|
|
return 1;
|
|
}
|
|
|
|
static int job_expect_named(void *data, int expired)
|
|
/* The real name server is expected to answer by now. */
|
|
{
|
|
if (!expired) return 0;
|
|
if (debug >= 2) printf("%s: Expect named\n", nowgmt());
|
|
|
|
if (expecting() && !searching()) {
|
|
/* No answer yet, start searching. */
|
|
start_searching();
|
|
force_expire(job_find_named);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static void sig_handler(int sig)
|
|
/* A signal forces a search for a real name daemon, etc. */
|
|
{
|
|
switch (sig) {
|
|
case SIGINT:
|
|
case SIGTERM: done= 1; break;
|
|
case SIGHUP: reinit= 1; break;
|
|
case SIGUSR1: debug++; break;
|
|
case SIGUSR2: debug= 0; break;
|
|
}
|
|
}
|
|
|
|
static void usage(void)
|
|
{
|
|
fprintf(stderr, "Usage: nonamed [-qs] [-d[level]] [-p port]\n");
|
|
exit(1);
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
job_t *job;
|
|
nwio_udpopt_t udpopt;
|
|
int i;
|
|
struct servent *servent;
|
|
struct sigaction sa;
|
|
FILE *fp;
|
|
int quit= 0;
|
|
|
|
/* Debug output must be line buffered. */
|
|
setvbuf(stdout, nil, _IOLBF, 0);
|
|
|
|
/* DNS service port number? */
|
|
if ((servent= getservbyname("domain", nil)) == nil) {
|
|
fprintf(stderr, "nonamed: \"domain\": unknown service\n");
|
|
exit(1);
|
|
}
|
|
my_port= servent->s_port;
|
|
named_port= servent->s_port;
|
|
|
|
i= 1;
|
|
while (i < argc && argv[i][0] == '-') {
|
|
char *opt= argv[i++] + 1, *end;
|
|
|
|
if (opt[0] == '-' && opt[1] == 0) break;
|
|
|
|
switch (*opt++) {
|
|
case 'd': /* Debug level. */
|
|
debug= 1;
|
|
if (between('0', *opt, '9')) debug= strtoul(opt, &opt, 10);
|
|
break;
|
|
case 'p': /* Port to listen to (for testing.) */
|
|
if (*opt == 0) {
|
|
if (i == argc) usage();
|
|
opt= argv[i++];
|
|
}
|
|
my_port= htons(strtoul(opt, &end, 0));
|
|
if (opt == end || *end != 0) usage();
|
|
opt= end;
|
|
break;
|
|
case 's':
|
|
single= 1;
|
|
break;
|
|
case 'q': /* Quit after printing cache contents. */
|
|
quit= 1;
|
|
break;
|
|
default:
|
|
usage();
|
|
}
|
|
}
|
|
if (i != argc) usage();
|
|
|
|
if (quit) {
|
|
/* Oops, just having a look at the cache. */
|
|
debug= 2;
|
|
now= time(nil);
|
|
n_datamax= -1;
|
|
file2cache();
|
|
return 0;
|
|
}
|
|
|
|
/* Don't die on broken pipes, reinitialize on hangup, etc. */
|
|
sa.sa_handler= SIG_IGN;
|
|
sigemptyset(&sa.sa_mask);
|
|
sa.sa_flags= 0;
|
|
sigaction(SIGPIPE, &sa, nil);
|
|
sa.sa_handler= sig_handler;
|
|
sigaction(SIGINT, &sa, nil);
|
|
sigaction(SIGHUP, &sa, nil);
|
|
sigaction(SIGUSR1, &sa, nil);
|
|
sigaction(SIGUSR2, &sa, nil);
|
|
sigaction(SIGTERM, &sa, nil);
|
|
|
|
/* TCP and UDP device names. */
|
|
if ((tcp_device= getenv("TCP_DEVICE")) == nil) tcp_device= TCP_DEVICE;
|
|
if ((udp_device= getenv("UDP_DEVICE")) == nil) udp_device= UDP_DEVICE;
|
|
|
|
/* Open an UDP channel for incoming DNS queries. */
|
|
if ((udp_fd= open(udp_device, O_RDWR)) < 0) fatal(udp_device);
|
|
|
|
udpopt.nwuo_flags= NWUO_EXCL | NWUO_LP_SET | NWUO_EN_LOC | NWUO_DI_BROAD
|
|
| NWUO_RP_ANY | NWUO_RA_ANY | NWUO_RWDATALL | NWUO_DI_IPOPT;
|
|
udpopt.nwuo_locport= my_port;
|
|
if (ioctl(udp_fd, NWIOSUDPOPT, &udpopt) == -1
|
|
|| ioctl(udp_fd, NWIOGUDPOPT, &udpopt) == -1
|
|
) {
|
|
fatal(udp_device);
|
|
}
|
|
|
|
/* The current time is... */
|
|
now= time(nil);
|
|
|
|
/* Read configuration and data cached by the previous nonamed. */
|
|
init_config(udpopt.nwuo_locaddr);
|
|
file2cache();
|
|
|
|
if (!single) {
|
|
/* Save process id. */
|
|
if ((fp= fopen(PIDFILE, "w")) != nil) {
|
|
fprintf(fp, "%u\n", (unsigned) getpid());
|
|
fclose(fp);
|
|
}
|
|
}
|
|
|
|
/* Jobs that start the ball rolling. */
|
|
newjob(job_read_udp, NEVER, nil);
|
|
newjob(job_setup_listen, IMMEDIATE, nil);
|
|
newjob(job_find_named, IMMEDIATE, nil);
|
|
|
|
while (!done) {
|
|
/* There is always something in the queue. */
|
|
assert(queue != nil);
|
|
|
|
/* Any expired jobs? */
|
|
while (queue->timeout <= now) {
|
|
(void) execjob(queue, 1);
|
|
assert(queue != nil);
|
|
}
|
|
|
|
/* Check I/O jobs. */
|
|
for (job= queue; job != nil; job= job->next) {
|
|
if (execjob(job, 0)) break;
|
|
}
|
|
|
|
if (queue->timeout != IMMEDIATE) {
|
|
struct timeval tv, *tvp;
|
|
|
|
if (debug >= 2) printf("%s: I/O wait", nowgmt());
|
|
|
|
if (queue->timeout != NEVER) {
|
|
tv.tv_sec= queue->timeout;
|
|
tv.tv_usec= 0;
|
|
tvp= &tv;
|
|
if (debug >= 2) printf(" (expires %s)\n", timegmt(tv.tv_sec));
|
|
} else {
|
|
tvp= nil;
|
|
if (debug >= 2) fputc('\n', stdout);
|
|
}
|
|
fflush(stdout);
|
|
|
|
if (asyn_wait(&asyn, 0, tvp) < 0) {
|
|
if (errno != EINTR && errno != EAGAIN) fatal("fwait()");
|
|
}
|
|
now= time(nil);
|
|
}
|
|
|
|
if (reinit) {
|
|
/* A hangup makes us go back to square one. */
|
|
reinit= 0;
|
|
if (ioctl(udp_fd, NWIOGUDPOPT, &udpopt) == -1) fatal(udp_device);
|
|
init_config(udpopt.nwuo_locaddr);
|
|
start_searching();
|
|
force_expire(job_find_named);
|
|
}
|
|
}
|
|
cache2file();
|
|
(void) unlink(PIDFILE);
|
|
if (debug >= 2) printf("sbrk(0) = %u\n", (unsigned) sbrk(0));
|
|
return 0;
|
|
}
|