ref: 963cfc9a6f6e721f52aa949e6d1af0c3e8dc2ecc
dir: /sys/src/cmd/upas/spf/dns.c/
#include "spf.h" extern char dflag; extern char vflag; extern char *netroot; static int timeout(void*, char *msg) { if(strstr(msg, "alarm")){ fprint(2, "deferred: dns timeout"); exits("deferred: dns timeout"); } return 0; } static Ndbtuple* tdnsquery(char *r, char *s, char *v) { long a; Ndbtuple *t; atnotify(timeout, 1); a = alarm(15*1000); t = dnsquery(r, s, v); alarm(a); atnotify(timeout, 0); return t; } Ndbtuple* vdnsquery(char *s, char *v, int recur) { Ndbtuple *n, *t; static int nquery; /* conflicts with standard: must limit to 10 and -> fail */ if(recur > 5 || ++nquery == 25){ fprint(2, "dns query limited %d %d\n", recur, nquery); return 0; } if(dflag) fprint(2, "dnsquery(%s, %s, %s) ->\n", netroot, s, v); t = tdnsquery(netroot, s, v); if(dflag) for(n = t; n; n = n->entry) fprint(2, "\t%s\t%s\n", n->attr, n->val); return t; } void dnreverse(char *s, int l, char *d) { char *p, *e, buf[100], *f[15]; int i, n; n = getfields(d, f, nelem(f), 0, "."); p = e = buf; if(l < sizeof buf) e += l; else e += sizeof buf; for(i = 1; i <= n; i++) p = seprint(p, e, "%s.", f[n-i]); if(p > buf) p = seprint(p-1, e, ".in-addr.arpa"); memmove(s, buf, p-buf+1); } int dncontains(char *d, char *s) { loop: if(!strcmp(d, s)) return 1; if(!(s = strchr(s, '.'))) return 0; s++; goto loop; }