#include "announce.h"
#include "util.h"
#include "dns.h"
+#include "cache.h"
+#include "service.h"
#include "interface.h"
-char rdata_buffer[MAX_DATA_LEN + 1];
static char name_buffer[MAX_NAME_LEN + 1];
+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";
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)
{
- 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(announce_ttl);
+ a->rdlength = cpu_to_be16(rdlength);
+ memcpy(a + 1, rdata, rdlength);
+
dns_answer_cnt++;
}
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);
- iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 3) + 1));
- iov[0].iov_base = &h;
- iov[0].iov_len = sizeof(struct dns_header);
-
- for (i = 0; i < dns_answer_cnt; i++) {
- struct dns_answer *a = &dns_reply[i].a;
- int id = (i * 3) + 1;
+ iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 2) + 1));
- 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);
+ iov[n_iov].iov_base = &h;
+ iov[n_iov].iov_len = sizeof(struct dns_header);
+ n_iov++;
- 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);
- }
- dns_answer_cnt = 0;
}
static int
return offset + 1;
}
-struct dns_header*
+static struct dns_header*
dns_consume_header(uint8_t **data, int *len)
{
struct dns_header *h = (struct dns_header *) *data;
return h;
}
-struct dns_question*
+static struct dns_question*
dns_consume_question(uint8_t **data, int *len)
{
struct dns_question *q = (struct dns_question *) *data;
return q;
}
-struct dns_answer*
+static struct dns_answer*
dns_consume_answer(uint8_t **data, int *len)
{
struct dns_answer *a = (struct dns_answer *) *data;
return a;
}
-char*
+static char *
dns_consume_name(const uint8_t *base, int blen, uint8_t **data, int *len)
{
int nlen = scan_name(*data, *len);
return name_buffer;
}
+
+static int
+parse_answer(struct interface *iface, uint8_t *buffer, int len, uint8_t **b, int *rlen, int cache)
+{
+ char *name = dns_consume_name(buffer, len, b, rlen);
+ struct dns_answer *a;
+ uint8_t *rdata;
+
+ if (!name) {
+ fprintf(stderr, "dropping: bad question\n");
+ return -1;
+ }
+
+ a = dns_consume_answer(b, rlen);
+ if (!a) {
+ fprintf(stderr, "dropping: bad question\n");
+ return -1;
+ }
+
+ rdata = *b;
+ if (a->rdlength > *rlen) {
+ fprintf(stderr, "dropping: bad question\n");
+ return -1;
+ }
+
+ *rlen -= a->rdlength;
+ *b += a->rdlength;
+
+ if (cache)
+ cache_answer(iface, buffer, len, name, a, rdata);
+
+ return 0;
+}
+
+static void
+parse_question(struct interface *iface, char *name, struct dns_question *q)
+{
+ char *host;
+
+ 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);
+ break;
+
+ case TYPE_PTR:
+ service_announce_services(iface, name);
+ service_reply(iface, name);
+ break;
+
+ case TYPE_AAAA:
+ case TYPE_A:
+ host = strstr(name, ".local");
+ if (host)
+ *host = '\0';
+ if (!strcmp(mdns_hostname, name))
+ service_reply_a(iface, q->type);
+ break;
+ };
+}
+
+void
+dns_handle_packet(struct interface *iface, uint8_t *buffer, int len)
+{
+ struct dns_header *h;
+ uint8_t *b = buffer;
+ int rlen = len;
+
+ h = dns_consume_header(&b, &rlen);
+ if (!h) {
+ fprintf(stderr, "dropping: bad header\n");
+ return;
+ }
+
+ while (h->questions-- > 0) {
+ char *name = dns_consume_name(buffer, len, &b, &rlen);
+ struct dns_question *q;
+
+ if (!name) {
+ fprintf(stderr, "dropping: bad name\n");
+ return;
+ }
+
+ q = dns_consume_question(&b, &rlen);
+ if (!q) {
+ fprintf(stderr, "dropping: bad question\n");
+ return;
+ }
+
+ if (!(h->flags & FLAG_RESPONSE))
+ parse_question(iface, name, q);
+ }
+
+ if (!(h->flags & FLAG_RESPONSE))
+ return;
+
+ while (h->answers-- > 0)
+ parse_answer(iface, buffer, len, &b, &rlen, 1);
+
+ while (h->authority-- > 0)
+ parse_answer(iface, buffer, len, &b, &rlen, 0);
+
+ while (h->additional-- > 0)
+ parse_answer(iface, buffer, len, &b, &rlen, 1);
+}
projects / project / mdnsd.git / blobdiff