net/dns: Switch mdns responder to new net_pkt API
Unfortunately, most of the dns pack/unpack code is not factorized, and mdns responder rewrites its own functions to write dns hdr, query, answer. Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
This commit is contained in:
Tomasz Bursztyka
Anas Nashif
parent
7bc61c1366
commit
87eb552dd2
@ -40,7 +40,7 @@ static struct net_context *ipv6;
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/* This value is recommended by RFC 1035 */
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#define DNS_RESOLVER_MAX_BUF_SIZE 512
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#define DNS_RESOLVER_MIN_BUF 1
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#define DNS_RESOLVER_MIN_BUF 2
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#define DNS_RESOLVER_BUF_CTR (DNS_RESOLVER_MIN_BUF + \
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CONFIG_MDNS_RESOLVER_ADDITIONAL_BUF_CTR)
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@ -105,53 +105,40 @@ static int bind_ctx(struct net_context *ctx,
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return ret;
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}
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#define append(pkt, type, value) \
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do { \
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if (!net_pkt_append_##type##_timeout(pkt, value, \
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BUF_ALLOC_TIMEOUT)) { \
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ret = -ENOMEM; \
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goto drop; \
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} \
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} while (0)
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#define append_all(pkt, size, value) \
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do { \
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if (!net_pkt_append_all(pkt, size, value, \
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BUF_ALLOC_TIMEOUT)) { \
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ret = -ENOMEM; \
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goto drop; \
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} \
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} while (0)
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static int setup_dns_hdr(struct net_pkt *pkt, u16_t answers)
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static void setup_dns_hdr(u8_t *buf, u16_t answers)
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{
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u16_t offset;
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u16_t flags;
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int ret;
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/* See RFC 1035, ch 4.1.1 for header details */
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flags = BIT(15); /* This is response */
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flags |= BIT(10); /* Authoritative Answer */
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append(pkt, be16, 0); /* Identifier, RFC 6762 ch 18.1 */
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append(pkt, be16, flags); /* Flags and codes */
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append(pkt, be16, 0); /* Question count */
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append(pkt, be16, answers); /* Answer RR count */
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append(pkt, be16, 0); /* Authority RR count */
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append(pkt, be16, 0); /* Additional RR count */
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UNALIGNED_PUT(0, (u16_t *)(buf)); /* Identifier, RFC 6762 ch 18.1 */
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offset = DNS_HEADER_ID_LEN;
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ret = 0;
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drop:
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return ret;
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UNALIGNED_PUT(htons(flags), (u16_t *)(buf+offset));
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offset += DNS_HEADER_FLAGS_LEN;
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UNALIGNED_PUT(0, (u16_t *)(buf + offset));
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offset += DNS_QDCOUNT_LEN;
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UNALIGNED_PUT(htons(answers), (u16_t *)(buf + offset));
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offset += DNS_ANCOUNT_LEN;
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UNALIGNED_PUT(0, (u16_t *)(buf + offset));
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offset += DNS_NSCOUNT_LEN;
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UNALIGNED_PUT(0, (u16_t *)(buf + offset));
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}
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static int add_answer(struct net_pkt *pkt, enum dns_rr_type qtype,
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struct net_buf *query, u32_t ttl,
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u16_t addr_len, u8_t *addr)
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static void add_answer(struct net_buf *query, enum dns_rr_type qtype,
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u32_t ttl, u16_t addr_len, u8_t *addr)
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{
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char *dot = query->data;
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char *dot = query->data + DNS_MSG_HEADER_SIZE;
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char *prev = NULL;
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int ret;
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u16_t offset;
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while ((dot = strchr(dot, '.'))) {
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if (!prev) {
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@ -167,59 +154,59 @@ static int add_answer(struct net_pkt *pkt, enum dns_rr_type qtype,
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*prev = strlen(prev) - 1;
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}
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append_all(pkt, query->len + 1, query->data);
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append(pkt, be16, qtype);
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offset = DNS_MSG_HEADER_SIZE + query->len;
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UNALIGNED_PUT(htons(qtype), (u16_t *)(query->data+offset));
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/* Bit 15 tells to flush the cache */
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append(pkt, be16, DNS_CLASS_IN | BIT(15));
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offset += DNS_QTYPE_LEN;
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UNALIGNED_PUT(htons(DNS_CLASS_IN | BIT(15)),
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(u16_t *)(query->data+offset));
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append(pkt, be32, ttl);
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append(pkt, be16, addr_len);
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append_all(pkt, addr_len, addr);
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ret = 0;
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offset += DNS_QCLASS_LEN;
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UNALIGNED_PUT(htonl(ttl), query->data + offset);
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drop:
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return ret;
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offset += DNS_TTL_LEN;
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UNALIGNED_PUT(htons(addr_len), query->data + offset);
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offset += DNS_RDLENGTH_LEN;
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memcpy(query->data + offset, addr, addr_len);
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}
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static struct net_pkt *create_answer(struct net_context *ctx,
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sa_family_t family,
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enum dns_rr_type qtype,
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struct net_buf *query,
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u16_t addr_len, u8_t *addr)
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static int create_answer(struct net_context *ctx,
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struct net_buf *query,
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enum dns_rr_type qtype,
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u16_t addr_len, u8_t *addr)
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{
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struct net_pkt *pkt;
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int ret;
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pkt = net_pkt_get_tx(ctx, BUF_ALLOC_TIMEOUT);
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if (!pkt) {
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return NULL;
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/* Prepare the response into the query buffer: move the name
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* query buffer has to get enough free space: dns_hdr + answer
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*/
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if ((query->size - query->len) < (DNS_MSG_HEADER_SIZE +
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DNS_QTYPE_LEN + DNS_QCLASS_LEN +
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DNS_TTL_LEN + DNS_RDLENGTH_LEN +
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addr_len)) {
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return -ENOBUFS;
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}
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net_pkt_set_family(pkt, family);
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memmove(query->data + DNS_MSG_HEADER_SIZE, query->data, query->len);
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if (setup_dns_hdr(pkt, 1) < 0) {
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goto drop;
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}
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setup_dns_hdr(query->data, 1);
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ret = add_answer(pkt, qtype, query, MDNS_TTL, addr_len, addr);
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if (ret < 0) {
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goto drop;
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}
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add_answer(query, qtype, MDNS_TTL, addr_len, addr);
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return pkt;
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query->len += DNS_MSG_HEADER_SIZE +
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DNS_QTYPE_LEN + DNS_QCLASS_LEN +
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DNS_TTL_LEN + DNS_RDLENGTH_LEN + addr_len;
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drop:
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net_pkt_unref(pkt);
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return NULL;
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return 0;
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}
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static int send_response(struct net_context *ctx, struct net_pkt *pkt,
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static int send_response(struct net_context *ctx,
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struct net_pkt *pkt,
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union net_ip_header *ip_hdr,
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struct net_buf *query,
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enum dns_rr_type qtype)
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{
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struct net_pkt *reply;
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struct sockaddr dst;
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socklen_t dst_len;
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int ret;
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@ -229,18 +216,18 @@ static int send_response(struct net_context *ctx, struct net_pkt *pkt,
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const struct in_addr *addr;
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addr = net_if_ipv4_select_src_addr(net_pkt_iface(pkt),
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&NET_IPV4_HDR(pkt)->src);
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&ip_hdr->ipv4->src);
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create_ipv4_addr(net_sin(&dst));
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dst_len = sizeof(struct sockaddr_in);
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reply = create_answer(ctx, AF_INET, qtype, query,
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ret = create_answer(ctx, query, qtype,
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sizeof(struct in_addr), (u8_t *)addr);
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if (!reply) {
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return -ENOMEM;
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if (ret != 0) {
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return ret;
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}
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net_pkt_set_ipv4_ttl(reply, 255);
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net_context_set_ipv4_ttl(ctx, 255);
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#else /* CONFIG_NET_IPV4 */
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return -EPFNOSUPPORT;
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#endif /* CONFIG_NET_IPV4 */
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@ -250,18 +237,18 @@ static int send_response(struct net_context *ctx, struct net_pkt *pkt,
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const struct in6_addr *addr;
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addr = net_if_ipv6_select_src_addr(net_pkt_iface(pkt),
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&NET_IPV6_HDR(pkt)->src);
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&ip_hdr->ipv6->src);
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create_ipv6_addr(net_sin6(&dst));
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dst_len = sizeof(struct sockaddr_in6);
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reply = create_answer(ctx, AF_INET6, qtype, query,
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ret = create_answer(ctx, query, qtype,
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sizeof(struct in6_addr), (u8_t *)addr);
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if (!reply) {
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if (ret != 0) {
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return -ENOMEM;
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}
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net_pkt_set_ipv6_hop_limit(reply, 255);
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net_context_set_ipv6_hop_limit(ctx, 255);
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#else /* CONFIG_NET_IPV6 */
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return -EPFNOSUPPORT;
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#endif /* CONFIG_NET_IPV6 */
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@ -271,11 +258,11 @@ static int send_response(struct net_context *ctx, struct net_pkt *pkt,
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return -EINVAL;
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}
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ret = net_context_sendto(reply, &dst, dst_len, NULL, K_NO_WAIT,
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NULL, NULL);
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ret = net_context_sendto_new(ctx, query->data, query->len,
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&dst, dst_len, NULL, K_NO_WAIT,
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NULL, NULL);
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if (ret < 0) {
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NET_DBG("Cannot send mDNS reply (%d)", ret);
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net_pkt_unref(reply);
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}
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return ret;
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@ -283,6 +270,7 @@ static int send_response(struct net_context *ctx, struct net_pkt *pkt,
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static int dns_read(struct net_context *ctx,
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struct net_pkt *pkt,
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union net_ip_header *ip_hdr,
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struct net_buf *dns_data,
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struct dns_addrinfo *info)
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{
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@ -293,18 +281,14 @@ static int dns_read(struct net_context *ctx,
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struct dns_msg_t dns_msg;
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int data_len;
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int queries;
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int offset;
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int ret;
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data_len = MIN(net_pkt_appdatalen(pkt), DNS_RESOLVER_MAX_BUF_SIZE);
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offset = net_pkt_get_len(pkt) - data_len;
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data_len = MIN(net_pkt_remaining_data(pkt), DNS_RESOLVER_MAX_BUF_SIZE);
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/* Store the DNS query name into a temporary net_buf. This means
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* that largest name we can resolve is CONFIG_NET_BUF_DATA_SIZE
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* which typically is 128 bytes. This is done using net_buf so that
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* we do not increase the stack usage of RX thread.
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/* Store the DNS query name into a temporary net_buf, which will be
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* enventually used to send a response
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*/
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result = net_pkt_get_data(ctx, BUF_ALLOC_TIMEOUT);
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result = net_buf_alloc(&mdns_msg_pool, BUF_ALLOC_TIMEOUT);
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if (!result) {
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ret = -ENOMEM;
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goto quit;
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@ -312,7 +296,7 @@ static int dns_read(struct net_context *ctx,
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/* TODO: Instead of this temporary copy, just use the net_pkt directly.
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*/
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ret = net_frag_linear_copy(dns_data, pkt->frags, offset, data_len);
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ret = net_pkt_read_new(pkt, dns_data->data, data_len);
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if (ret < 0) {
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goto quit;
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}
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@ -366,7 +350,7 @@ static int dns_read(struct net_context *ctx,
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&(result->data + 1)[hostname_len] == lquery) {
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NET_DBG("mDNS query to our hostname %s.local",
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hostname);
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send_response(ctx, pkt, result, qtype);
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send_response(ctx, pkt, ip_hdr, result, qtype);
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}
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} while (--queries);
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@ -374,7 +358,7 @@ static int dns_read(struct net_context *ctx,
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quit:
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if (result) {
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net_pkt_frag_unref(result);
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net_buf_unref(result);
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}
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return ret;
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@ -408,7 +392,7 @@ static void recv_cb(struct net_context *net_ctx,
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goto quit;
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}
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ret = dns_read(ctx, pkt, dns_data, &info);
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ret = dns_read(ctx, pkt, ip_hdr, dns_data, &info);
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if (ret < 0 && ret != -EINVAL) {
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NET_DBG("mDNS read failed (%d)", ret);
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}
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