rename mdns_add_records to cache_dump_records and move it to cache.c
[project/mdnsd.git] / dns.c
diff --git a/dns.c b/dns.c
index 6389f8c..4951774 100644 (file)
--- a/dns.c
+++ b/dns.c
 #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];
 
 const char*
@@ -66,10 +68,8 @@ dns_type_string(uint16_t type)
 }
 
 void
-dns_send_question(struct uloop_fd *u, char *question, int type)
+dns_send_question(struct interface *iface, const char *question, int type)
 {
-       static size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_pktinfo)) / sizeof(size_t)) + 1];
-       static unsigned char buffer[MAX_NAME_LEN];
        static struct dns_header h = {
                .questions = cpu_to_be16(1),
        };
@@ -82,49 +82,24 @@ dns_send_question(struct uloop_fd *u, char *question, int type)
                        .iov_len = sizeof(h),
                },
                {
-                       .iov_base = buffer,
+                       .iov_base = name_buffer,
                },
                {
                        .iov_base = &q,
                        .iov_len = sizeof(q),
                }
        };
-       static struct sockaddr_in a = {
-               .sin_family = AF_INET,
-               .sin_port = htons(MCAST_PORT),
-       };
-       static struct msghdr m = {
-               .msg_name = (struct sockaddr *) &a,
-               .msg_namelen = sizeof(a),
-               .msg_iov = iov,
-               .msg_iovlen = ARRAY_SIZE(iov),
-               .msg_control = cmsg_data,
-               .msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)),
-       };
-       struct in_pktinfo *pkti;
-       struct cmsghdr *cmsg;
        int len;
 
-       a.sin_addr.s_addr = inet_addr(MCAST_ADDR);
        q.type = __cpu_to_be16(type);
 
-       len = dn_comp(question, buffer, MAX_NAME_LEN, NULL, NULL);
+       len = dn_comp(question, (void *) name_buffer, sizeof(name_buffer), NULL, NULL);
        if (len < 1)
                return;
 
        iov[1].iov_len = len;
 
-       memset(cmsg_data, 0, sizeof(cmsg_data));
-
-       cmsg = CMSG_FIRSTHDR(&m);
-       cmsg->cmsg_len = m.msg_controllen;
-       cmsg->cmsg_level = IPPROTO_IP;
-       cmsg->cmsg_type = IP_PKTINFO;
-
-       pkti = (struct in_pktinfo*) CMSG_DATA(cmsg);
-       pkti->ipi_ifindex = iface_index;
-
-       if (sendmsg(u->fd, &m, 0) < 0)
+       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);
@@ -150,7 +125,7 @@ dns_init_answer(void)
 }
 
 void
-dns_add_answer(int type, uint8_t *rdata, uint16_t rdlength)
+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)
@@ -162,34 +137,20 @@ dns_add_answer(int type, uint8_t *rdata, uint16_t rdlength)
 }
 
 void
-dns_send_answer(struct uloop_fd *u, char *answer)
+dns_send_answer(struct interface *iface, const char *answer)
 {
        uint8_t buffer[256];
        struct dns_header h = { 0 };
-       struct msghdr m = { 0 };
        struct iovec *iov;
-       struct sockaddr_in in = { 0 };
        int len, i;
 
        if (!dns_answer_cnt)
                return;
 
-       in.sin_family = AF_INET;
-       in.sin_addr.s_addr = inet_addr(MCAST_ADDR);
-       in.sin_port = htons(MCAST_PORT);
-
        h.answers = __cpu_to_be16(dns_answer_cnt);
        h.flags = __cpu_to_be16(0x8400);
 
-       iov = malloc(sizeof(struct iovec) * ((dns_answer_cnt * 3) + 1));
-       if (!iov)
-               return;
-
-       m.msg_name = &in;
-       m.msg_namelen = sizeof(struct sockaddr_in);
-       m.msg_iov = iov;
-       m.msg_iovlen = (dns_answer_cnt * 3) + 1;
-
+       iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 3) + 1));
        iov[0].iov_base = &h;
        iov[0].iov_len = sizeof(struct dns_header);
 
@@ -219,7 +180,7 @@ dns_send_answer(struct uloop_fd *u, char *answer)
                DBG(1, "A <- %s %s\n", dns_type_string(dns_reply[i].type), answer);
        }
 
-       if (sendmsg(u->fd, &m, 0) < 0)
+       if (interface_send_packet(iface, iov, (dns_answer_cnt * 3) + 1) < 0)
                fprintf(stderr, "failed to send question\n");
 
        for (i = 0; i < dns_answer_cnt; i++) {
@@ -230,7 +191,7 @@ dns_send_answer(struct uloop_fd *u, char *answer)
 }
 
 static int
-scan_name(uint8_t *buffer, int len)
+scan_name(const uint8_t *buffer, int len)
 {
        int offset = 0;
 
@@ -251,7 +212,7 @@ scan_name(uint8_t *buffer, int len)
        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;
@@ -272,7 +233,7 @@ dns_consume_header(uint8_t **data, int *len)
        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;
@@ -293,7 +254,7 @@ dns_consume_question(uint8_t **data, int *len)
        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;
@@ -312,8 +273,8 @@ dns_consume_answer(uint8_t **data, int *len)
        return a;
 }
 
-char*
-dns_consume_name(uint8_t *base, int blen, uint8_t **data, int *len)
+static char *
+dns_consume_name(const uint8_t *base, int blen, uint8_t **data, int *len)
 {
        int nlen = scan_name(*data, *len);
 
@@ -330,3 +291,111 @@ dns_consume_name(uint8_t *base, int blen, uint8_t **data, int *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:
+               host = service_name("local");
+               if (!strcmp(name, host))
+                       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(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);
+}