X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fmdnsd.git;a=blobdiff_plain;f=dns.c;h=550befc24c1593ca2f7bcef14fed22456304908f;hp=c1c280341449331bcf39d1efb0d0ba59692d4246;hb=9879d5fcafed84a912baa8e2e2d3e73df1a9236d;hpb=67e8c3bed831f8a1b879a654ca290d14e333664a diff --git a/dns.c b/dns.c index c1c2803..550befc 100644 --- a/dns.c +++ b/dns.c @@ -15,6 +15,7 @@ #include #include +#include #include #include #include @@ -22,7 +23,6 @@ #include #include #include -#include #include #include #include @@ -39,51 +39,46 @@ #include "service.h" #include "interface.h" -char rdata_buffer[MAX_DATA_LEN + 1]; static char name_buffer[MAX_NAME_LEN + 1]; +static char dns_buffer[MAX_NAME_LEN]; +static struct blob_buf ans_buf; const char* dns_type_string(uint16_t type) { - switch (type) { - case TYPE_A: - return "A"; - - case TYPE_AAAA: - return "AAAA"; - - case TYPE_PTR: - return "PTR"; - - case TYPE_TXT: - return "TXT"; - - case TYPE_SRV: - return "SRV"; + static const struct { + uint16_t type; + char str[5]; + } type_str[] = { + { TYPE_A, "A" }, + { TYPE_AAAA, "AAAA" }, + { TYPE_PTR, "PTR" }, + { TYPE_TXT, "TXT" }, + { TYPE_SRV, "SRV" }, + { TYPE_ANY, "ANY" }, + }; + int i; - case TYPE_ANY: - return "ANY"; + for (i = 0; i < ARRAY_SIZE(type_str); i++) { + if (type == type_str[i].type) + return type_str[i].str; } return "N/A"; } void -dns_send_question(struct interface *iface, const char *question, int type) +dns_send_question(struct interface *iface, const char *question, int type, int multicast) { - 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, .iov_len = sizeof(h), }, { - .iov_base = name_buffer, + .iov_base = dns_buffer, }, { .iov_base = &q, @@ -92,18 +87,19 @@ 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((multicast ? 0 : CLASS_UNICAST) | 1); + q.type = cpu_to_be16(type); - len = dn_comp(question, (void *) name_buffer, sizeof(name_buffer), NULL, NULL); + len = dn_comp(question, (void *) dns_buffer, sizeof(dns_buffer), NULL, NULL); if (len < 1) return; 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 :"); } @@ -115,25 +111,29 @@ struct dns_reply { char *buffer; }; -#define MAX_ANSWER 8 -static struct dns_reply dns_reply[1 + (MAX_ANSWER * 3)]; static int dns_answer_cnt; void dns_init_answer(void) { dns_answer_cnt = 0; + blob_buf_init(&ans_buf, 0); } 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 dns_reply *a = &dns_reply[dns_answer_cnt]; - if (dns_answer_cnt == MAX_ANSWER) - return; - a->rdata = memdup(rdata, rdlength); - a->type = type; - a->rdlength = rdlength; + struct blob_attr *attr; + struct dns_answer *a; + + attr = blob_new(&ans_buf, 0, sizeof(*a) + rdlength); + a = blob_data(attr); + a->type = cpu_to_be16(type); + a->class = cpu_to_be16(1); + a->ttl = cpu_to_be32(ttl); + a->rdlength = cpu_to_be16(rdlength); + memcpy(a + 1, rdata, rdlength); + dns_answer_cnt++; } @@ -141,54 +141,73 @@ void dns_send_answer(struct interface *iface, const char *answer) { uint8_t buffer[256]; + struct blob_attr *attr; struct dns_header h = { 0 }; struct iovec *iov; - int len, i; + int answer_len, rem; + int n_iov = 0; 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 * 3) + 1)); - iov[0].iov_base = &h; - iov[0].iov_len = sizeof(struct dns_header); + iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 2) + 1)); - for (i = 0; i < dns_answer_cnt; i++) { - struct dns_answer *a = &dns_reply[i].a; - int id = (i * 3) + 1; + iov[n_iov].iov_base = &h; + iov[n_iov].iov_len = sizeof(struct dns_header); + n_iov++; - memset(a, 0, sizeof(*a)); - a->type = __cpu_to_be16(dns_reply[i].type); - a->class = __cpu_to_be16(1); - a->ttl = __cpu_to_be32(announce_ttl); - a->rdlength = __cpu_to_be16(dns_reply[i].rdlength); - - len = dn_comp(answer, buffer, sizeof(buffer), NULL, NULL); - if (len < 1) - return; + answer_len = dn_comp(answer, buffer, sizeof(buffer), NULL, NULL); + if (answer_len < 1) + return; - dns_reply[i].buffer = iov[id].iov_base = memdup(buffer, len); - iov[id].iov_len = len; + blob_for_each_attr(attr, ans_buf.head, rem) { + struct dns_answer *a = blob_data(attr); - iov[id + 1].iov_base = a; - iov[id + 1].iov_len = sizeof(struct dns_answer); + iov[n_iov].iov_base = buffer; + iov[n_iov].iov_len = answer_len; + n_iov++; - iov[id + 2].iov_base = dns_reply[i].rdata; - iov[id + 2].iov_len = dns_reply[i].rdlength; + iov[n_iov].iov_base = blob_data(attr); + iov[n_iov].iov_len = blob_len(attr); + n_iov++; - DBG(1, "A <- %s %s\n", dns_type_string(dns_reply[i].type), answer); + DBG(1, "A <- %s %s\n", dns_type_string(be16_to_cpu(a->type)), answer); } - if (interface_send_packet(iface, iov, (dns_answer_cnt * 3) + 1) < 0) + if (interface_send_packet(iface, iov, n_iov) < 0) fprintf(stderr, "failed to send question\n"); +} - for (i = 0; i < dns_answer_cnt; i++) { - free(dns_reply[i].buffer); - free(dns_reply[i].rdata); +void +dns_reply_a(struct interface *iface, int ttl) +{ + struct ifaddrs *ifap, *ifa; + struct sockaddr_in *sa; + struct sockaddr_in6 *sa6; + + getifaddrs(&ifap); + + dns_init_answer(); + for (ifa = ifap; ifa; ifa = ifa->ifa_next) { + if (strcmp(ifa->ifa_name, iface->name)) + continue; + if (ifa->ifa_addr->sa_family == AF_INET) { + sa = (struct sockaddr_in *) ifa->ifa_addr; + dns_add_answer(TYPE_A, (uint8_t *) &sa->sin_addr, 4, ttl); + } + if (ifa->ifa_addr->sa_family == AF_INET6) { + uint8_t ll_prefix[] = {0xfe, 0x80 }; + sa6 = (struct sockaddr_in6 *) ifa->ifa_addr; + if (!memcmp(&sa6->sin6_addr, &ll_prefix, 2)) + dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl); + } } - dns_answer_cnt = 0; + dns_send_answer(iface, mdns_hostname_local); + + freeifaddrs(ifap); } static int @@ -224,7 +243,7 @@ dns_consume_header(uint8_t **data, int *len) return NULL; while (endianess--) { - *swap = __be16_to_cpu(*swap); + *swap = be16_to_cpu(*swap); swap++; } @@ -245,7 +264,7 @@ dns_consume_question(uint8_t **data, int *len) return NULL; while (endianess--) { - *swap = __be16_to_cpu(*swap); + *swap = be16_to_cpu(*swap); swap++; } @@ -263,10 +282,10 @@ 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); @@ -311,6 +330,9 @@ 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"); @@ -321,7 +343,7 @@ 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; } @@ -331,18 +353,25 @@ 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: - host = service_name("local"); - if (!strcmp(name, host)) - service_reply(iface, NULL); + if (!strcmp(name, mdns_hostname_local)) { + service_reply(iface, NULL, announce_ttl); + dns_reply_a(iface, announce_ttl); + } break; case TYPE_PTR: - service_announce_services(iface, name); - service_reply(iface, name); + if (!strcmp(name, sdudp)) + service_announce_services(iface, 0, announce_ttl); + else if (!strcmp(name, sdtcp)) + service_announce_services(iface, 1, announce_ttl); + service_reply(iface, name, announce_ttl); break; case TYPE_AAAA: @@ -350,14 +379,14 @@ parse_question(struct interface *iface, char *name, struct dns_question *q) host = strstr(name, ".local"); if (host) *host = '\0'; - if (!strcmp(hostname, name)) - service_reply_a(iface, q->type); + if (!strcmp(mdns_hostname, name)) + dns_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; @@ -369,6 +398,10 @@ 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; @@ -392,11 +425,15 @@ 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; + }