diff options
Diffstat (limited to 'crypto/heimdal/lib/roken/resolve.c')
| -rw-r--r-- | crypto/heimdal/lib/roken/resolve.c | 117 |
1 files changed, 115 insertions, 2 deletions
diff --git a/crypto/heimdal/lib/roken/resolve.c b/crypto/heimdal/lib/roken/resolve.c index 76df287..eddaa7d 100644 --- a/crypto/heimdal/lib/roken/resolve.c +++ b/crypto/heimdal/lib/roken/resolve.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 1995 - 2000 Kungliga Tekniska Högskolan + * Copyright (c) 1995 - 2001 Kungliga Tekniska Högskolan * (Royal Institute of Technology, Stockholm, Sweden). * All rights reserved. * @@ -43,7 +43,9 @@ #endif #include "resolve.h" -RCSID("$Id: resolve.c,v 1.26 2000/06/27 01:15:53 assar Exp $"); +#include <assert.h> + +RCSID("$Id: resolve.c,v 1.30 2001/10/02 15:39:41 joda Exp $"); #if defined(HAVE_RES_SEARCH) && defined(HAVE_DN_EXPAND) @@ -360,6 +362,109 @@ dns_lookup(const char *domain, const char *type_name) return dns_lookup_int(domain, C_IN, type); } +static int +compare_srv(const void *a, const void *b) +{ + const struct resource_record *const* aa = a, *const* bb = b; + + if((*aa)->u.srv->priority == (*bb)->u.srv->priority) + return ((*aa)->u.srv->weight - (*bb)->u.srv->weight); + return ((*aa)->u.srv->priority - (*bb)->u.srv->priority); +} + +#ifndef HAVE_RANDOM +#define random() rand() +#endif + +/* try to rearrange the srv-records by the algorithm in RFC2782 */ +void +dns_srv_order(struct dns_reply *r) +{ + struct resource_record **srvs, **ss, **headp; + struct resource_record *rr; + int num_srv = 0; + +#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE) + char state[256], *oldstate; +#endif + + for(rr = r->head; rr; rr = rr->next) + if(rr->type == T_SRV) + num_srv++; + + if(num_srv == 0) + return; + + srvs = malloc(num_srv * sizeof(*srvs)); + if(srvs == NULL) + return; /* XXX not much to do here */ + + /* unlink all srv-records from the linked list and put them in + a vector */ + for(ss = srvs, headp = &r->head; *headp; ) + if((*headp)->type == T_SRV) { + *ss = *headp; + *headp = (*headp)->next; + (*ss)->next = NULL; + ss++; + } else + headp = &(*headp)->next; + + /* sort them by priority and weight */ + qsort(srvs, num_srv, sizeof(*srvs), compare_srv); + +#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE) + oldstate = initstate(time(NULL), state, sizeof(state)); +#endif + + headp = &r->head; + + for(ss = srvs; ss < srvs + num_srv; ) { + int sum, rnd, count; + struct resource_record **ee, **tt; + /* find the last record with the same priority and count the + sum of all weights */ + for(sum = 0, tt = ss; tt < srvs + num_srv; tt++) { + if(*tt == NULL) + continue; + if((*tt)->u.srv->priority != (*ss)->u.srv->priority) + break; + sum += (*tt)->u.srv->weight; + } + ee = tt; + /* ss is now the first record of this priority and ee is the + first of the next */ + while(ss < ee) { + rnd = random() % (sum + 1); + for(count = 0, tt = ss; ; tt++) { + if(*tt == NULL) + continue; + count += (*tt)->u.srv->weight; + if(count >= rnd) + break; + } + + assert(tt < ee); + + /* insert the selected record at the tail (of the head) of + the list */ + (*tt)->next = *headp; + *headp = *tt; + headp = &(*tt)->next; + sum -= (*tt)->u.srv->weight; + *tt = NULL; + while(ss < ee && *ss == NULL) + ss++; + } + } + +#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE) + setstate(oldstate); +#endif + free(srvs); + return; +} + #else /* NOT defined(HAVE_RES_SEARCH) && defined(HAVE_DN_EXPAND) */ struct dns_reply * @@ -373,6 +478,11 @@ dns_free_data(struct dns_reply *r) { } +void +dns_srv_order(struct dns_reply *r) +{ +} + #endif #ifdef TEST @@ -386,6 +496,9 @@ main(int argc, char **argv) printf("No reply.\n"); return 1; } + if(r->q.type == T_SRV) + dns_srv_order(r); + for(rr = r->head; rr;rr=rr->next){ printf("%s %s %d ", rr->domain, dns_type_to_string(rr->type), rr->ttl); switch(rr->type){ |
