Subversion Repositories planix.SVN

/* RFC2136 DNS inform - necessary for Win2k3 DNS servers */
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ndb.h>
#include <ip.h>
#include "dns.h"

enum {
        FQDNMAX = 255,
};

char *errmsgs[] = {
        [0]  "ok",
        [1]  "request format error",
        [2]  "internal server error",
        [3]  "domain name does not exist",
        [4]  "request not supported",
        [5]  "permission denied",
        [6]  "domain name already exists",
        [7]  "resource record already exists",
        [8]  "resource record does not exist",
        [9]  "server not authoritative",
        [10] "domain name not in zone",
};

void
usage(void)
{
        fprint(2, "usage: %s [-x netmtpt]\n", argv0);
        exits("usage");
}

void
ding(void *, char *msg)
{
        if(strstr(msg, "alarm") != nil)
                noted(NCONT);
        noted(NDFLT);
}

int
g16(uchar **p)
{
        int n;

        n  = *(*p)++ << 8;
        n |= *(*p)++;
        return n;
}

void
p16(uchar **p, int n)
{
        *(*p)++ = n >> 8;
        *(*p)++ = n;
}

void
p32(uchar **p, int n)
{
        *(*p)++ = n >> 24;
        *(*p)++ = n >> 16;
        *(*p)++ = n >> 8;
        *(*p)++ = n;
}

void
pmem(uchar **p, void *v, int len)
{
        memmove(*p, v, len);
        *p += len;
}

void
pname(uchar **p, char *s)
{
        uchar *len;

        while (*s){
                len = (*p)++;
                while(*s && *s != '.')
                        *(*p)++ = *s++;
                *len = *p - len - 1;
                if(*s == '.')
                        s++;
        }
        *(*p)++ = 0;
}

void
main(int argc, char *argv[])
{
        int debug, len, fd;
        uint err;
        char *sysname, *dnsdomain, *dom, *inform, *ns, net[32];
        uchar *p, buf[4096], addr[IPv4addrlen], v6addr[IPaddrlen];
        ushort txid;
        Ndb *db;
        Ndbtuple *t, *tt;
        static char *query[] = { "dom", "dnsdomain", "ns", "inform" };

        fmtinstall('I', eipfmt);
        fmtinstall('V', eipfmt);
        setnetmtpt(net, sizeof net, nil);

        debug = 0;
        ns = nil;
        dom = nil;
        inform = nil;
        dnsdomain = nil;
        ARGBEGIN{
        case 'd':
                debug = 1;
                break;
        case 'x':
                setnetmtpt(net, sizeof net, EARGF(usage()));
                break;
        default:
                usage();
        }ARGEND;

        if(argc != 0)
                usage();

        if((sysname = getenv("sysname")) == nil)
                sysfatal("$sysname not set");

        if((db = ndbopen(nil)) == nil)
                sysfatal("can't open ndb: %r");
        tt = ndbipinfo(db, "sys", sysname, query, nelem(query));
        for(t = tt; t; t = t->entry){
                if(strcmp(t->attr, "ns") == 0)
                        ns = t->val;
                else if(strcmp(t->attr, "dom") == 0)
                        dom = t->val;
                else if(strcmp(t->attr, "dnsdomain") == 0)
                        dnsdomain = t->val;
                else if(strcmp(t->attr, "inform") == 0)
                        inform = t->val;
        }

        ndbfree(tt);
        ndbclose(db);

        if(inform)
                dom = inform;
        if(!ns)
                sysfatal("no relevant ns=");
        if(!dom)
                sysfatal("no relevant dom=");
        if(!dnsdomain)
                sysfatal("no relevant dnsdomain=");

        myipaddr(v6addr, net);
        memmove(addr, v6addr + IPaddrlen - IPv4addrlen, IPv4addrlen);

        if(debug){
                print("ip=%V\n", addr);
                print("ns=%s\n", ns);
                print("dnsdomain=%s\n", dnsdomain);
                print("dom=%s\n", dom);
        }

        if((fd = dial(netmkaddr(ns, "udp", "dns"), 0, 0, 0)) < 0)
                sysfatal("can't dial %s: %r", ns);

        txid = time(nil) + getpid();

        p = buf;
        p16(&p, txid);          /* ID */
        p16(&p, 5<<11);         /* flags */
        p16(&p, 1);             /* # Zones */
        p16(&p, 0);             /* # prerequisites */
        p16(&p, 2);             /* # updates */
        p16(&p, 0);             /* # additionals */

        pname(&p, dnsdomain);   /* zone */
        p16(&p, Tsoa);          /* zone type */
        p16(&p, Cin);           /* zone class */

        /* delete old name */
        pname(&p, dom);         /* name */
        p16(&p, Ta);            /* type: v4 addr */
        p16(&p, Call);          /* class */
        p32(&p, 0);             /* TTL */
        p16(&p, 0);             /* data len */

        /* add new A record */
        pname(&p, dom);         /* name */
        p16(&p, Ta);            /* type: v4 addr */
        p16(&p, Cin);           /* class */
        p32(&p, 60*60*25);      /* TTL (25 hours) */
        p16(&p, IPv4addrlen);   /* data len */
        pmem(&p, addr, IPv4addrlen);    /* v4 address */

        len = p - buf;
        if(write(fd, buf, len) != len)
                sysfatal("write failed: %r");

        notify(ding);
        alarm(3000);
        do{
                if(read(fd, buf, sizeof buf) < 0)
                        sysfatal("timeout");
                p = buf;
        }while(g16(&p) != txid);
        alarm(0);

        close(fd);

        err = g16(&p) & 7;
        if(err != 0 && err != 7)        /* err==7 is just a "yes, I know" warning */
                if(err < nelem(errmsgs))
                        sysfatal("%s", errmsgs[err]);
                else
                        sysfatal("unknown dns server error %d", err);
        exits(0);
}