X-Git-Url: https://git.archive.openwrt.org/?a=blobdiff_plain;f=dns.c;h=c5323e5e93c449af5ff38913dc8ec5c6a6a18687;hb=d958ed0a279467d7a4e538b52214ab36c8b2abd8;hp=fc93f4a4fd88eb686c17cf3e74814972b56f9e3c;hpb=30d33913cb2d8e895ebf1c79595a0ebf901d925b;p=project%2Fmdnsd.git diff --git a/dns.c b/dns.c index fc93f4a..c5323e5 100644 --- a/dns.c +++ b/dns.c @@ -22,7 +22,6 @@ #include #include #include -#include #include #include #include @@ -67,14 +66,10 @@ dns_type_string(uint16_t type) } void -dns_send_question(struct interface *iface, const char *question, int type) +dns_send_question(struct interface *iface, const char *question, int type, int unicast) { - static struct dns_header h = { - .questions = cpu_to_be16(1), - }; - static struct dns_question q = { - .class = cpu_to_be16(1), - }; + static struct dns_header h; + static struct dns_question q; static struct iovec iov[] = { { .iov_base = &h, @@ -90,7 +85,9 @@ dns_send_question(struct interface *iface, const char *question, int type) }; int len; - q.type = __cpu_to_be16(type); + h.questions = cpu_to_be16(1); + q.class = cpu_to_be16(((unicast) ? (CLASS_UNICAST) : (0)) | 1); + q.type = cpu_to_be16(type); len = dn_comp(question, (void *) name_buffer, sizeof(name_buffer), NULL, NULL); if (len < 1) @@ -98,10 +95,9 @@ dns_send_question(struct interface *iface, const char *question, int type) iov[1].iov_len = len; + DBG(1, "Q <- %s %s\n", dns_type_string(type), question); if (interface_send_packet(iface, iov, ARRAY_SIZE(iov)) < 0) - fprintf(stderr, "failed to send question\n"); - else - DBG(1, "Q <- %s %s\n", dns_type_string(type), question); + perror("failed to send question :"); } @@ -123,7 +119,7 @@ dns_init_answer(void) } void -dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength) +dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength, int ttl) { struct blob_attr *attr; struct dns_answer *a; @@ -132,7 +128,7 @@ dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength) a = blob_data(attr); a->type = cpu_to_be16(type); a->class = cpu_to_be16(1); - a->ttl = cpu_to_be32(announce_ttl); + a->ttl = cpu_to_be32(ttl); a->rdlength = cpu_to_be16(rdlength); memcpy(a + 1, rdata, rdlength); @@ -152,8 +148,8 @@ dns_send_answer(struct interface *iface, const char *answer) if (!dns_answer_cnt) return; - h.answers = __cpu_to_be16(dns_answer_cnt); - h.flags = __cpu_to_be16(0x8400); + h.answers = cpu_to_be16(dns_answer_cnt); + h.flags = cpu_to_be16(0x8400); iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 2) + 1)); @@ -216,7 +212,7 @@ dns_consume_header(uint8_t **data, int *len) return NULL; while (endianess--) { - *swap = __be16_to_cpu(*swap); + *swap = be16_to_cpu(*swap); swap++; } @@ -237,7 +233,7 @@ dns_consume_question(uint8_t **data, int *len) return NULL; while (endianess--) { - *swap = __be16_to_cpu(*swap); + *swap = be16_to_cpu(*swap); swap++; } @@ -255,10 +251,10 @@ dns_consume_answer(uint8_t **data, int *len) if (*len < sizeof(struct dns_answer)) return NULL; - a->type = __be16_to_cpu(a->type); - a->class = __be16_to_cpu(a->class); - a->ttl = __be32_to_cpu(a->ttl); - a->rdlength = __be16_to_cpu(a->rdlength); + a->type = be16_to_cpu(a->type); + a->class = be16_to_cpu(a->class); + a->ttl = be32_to_cpu(a->ttl); + a->rdlength = be16_to_cpu(a->rdlength); *len -= sizeof(struct dns_answer); *data += sizeof(struct dns_answer); @@ -303,6 +299,9 @@ parse_answer(struct interface *iface, uint8_t *buffer, int len, uint8_t **b, int return -1; } + if ((a->class & ~CLASS_FLUSH) != CLASS_IN) + return -1; + rdata = *b; if (a->rdlength > *rlen) { fprintf(stderr, "dropping: bad question\n"); @@ -313,7 +312,7 @@ parse_answer(struct interface *iface, uint8_t *buffer, int len, uint8_t **b, int *b += a->rdlength; if (cache) - cache_answer(iface, buffer, len, name, a, rdata); + cache_answer(iface, buffer, len, name, a, rdata, a->class & CLASS_FLUSH); return 0; } @@ -323,17 +322,20 @@ parse_question(struct interface *iface, char *name, struct dns_question *q) { char *host; + if ((q->class & CLASS_UNICAST) && iface->multicast) + iface = iface->peer; + DBG(1, "Q -> %s %s\n", dns_type_string(q->type), name); switch (q->type) { case TYPE_ANY: if (!strcmp(name, mdns_hostname_local)) - service_reply(iface, NULL); + service_reply(iface, NULL, announce_ttl); break; case TYPE_PTR: - service_announce_services(iface, name); - service_reply(iface, name); + service_announce_services(iface, name, announce_ttl); + service_reply(iface, name, announce_ttl); break; case TYPE_AAAA: @@ -342,13 +344,13 @@ parse_question(struct interface *iface, char *name, struct dns_question *q) if (host) *host = '\0'; if (!strcmp(mdns_hostname, name)) - service_reply_a(iface, q->type); + service_reply_a(iface, announce_ttl); break; }; } void -dns_handle_packet(struct interface *iface, uint8_t *buffer, int len) +dns_handle_packet(struct interface *iface, struct sockaddr *s, uint16_t port, uint8_t *buffer, int len) { struct dns_header *h; uint8_t *b = buffer; @@ -360,6 +362,10 @@ dns_handle_packet(struct interface *iface, uint8_t *buffer, int len) return; } + if (h->questions && !iface->multicast && port != 5353) + // silently drop unicast questions that dont originate from port 5353 + return; + while (h->questions-- > 0) { char *name = dns_consume_name(buffer, len, &b, &rlen); struct dns_question *q; @@ -383,11 +389,15 @@ dns_handle_packet(struct interface *iface, uint8_t *buffer, int len) return; while (h->answers-- > 0) - parse_answer(iface, buffer, len, &b, &rlen, 1); + if (parse_answer(iface, buffer, len, &b, &rlen, 1)) + return; while (h->authority-- > 0) - parse_answer(iface, buffer, len, &b, &rlen, 0); + if (parse_answer(iface, buffer, len, &b, &rlen, 1)) + return; while (h->additional-- > 0) - parse_answer(iface, buffer, len, &b, &rlen, 1); + if (parse_answer(iface, buffer, len, &b, &rlen, 1)) + return; + }