mdns: Use memcpy() for copy to support non-text TXTs
@@ -513,6 +513,37 @@ static inline uint8_t _mdns_append_string(uint8_t * packet, uint16_t * index, co
return len + 1;
}
+/**
+ * @brief appends one TXT record ("key=value" or "key")
+ *
+ * @param packet MDNS packet
+ * @param index offset in the packet
+ * @param txt one txt record
+ *
+ * @return length of added data: length of the added txt value + 1 on success
+ * 0 if data won't fit the packet
+ * -1 if invalid TXT entry
+ */
+static inline int append_one_txt_record_entry(uint8_t * packet, uint16_t * index, mdns_txt_linked_item_t * txt)
+{
+ if (txt == NULL || txt->key == NULL) {
+ return -1;
+ }
+ size_t key_len = strlen(txt->key);
+ size_t len = key_len + txt->value_len + (txt->value ? 1 : 0);
+ if ((*index + len + 1) >= MDNS_MAX_PACKET_SIZE) {
+ return 0;
+ }
+ _mdns_append_u8(packet, index, len);
+ memcpy(packet + *index, txt->key, key_len);
+ if (txt->value) {
+ packet[*index + key_len] = '=';
+ memcpy(packet + *index + key_len + 1, txt->value, txt->value_len);
+ }
+ *index += len;
+ return len + 1;
+}
+
/**
* @brief appends FQDN to a packet, incrementing the index and
* compressing the output if previous occurrence of the string (or part of it) has been found
@@ -775,19 +806,13 @@ static uint16_t _mdns_append_txt_record(uint8_t * packet, uint16_t * index, mdns
uint16_t data_len_location = *index - 2;
uint16_t data_len = 0;
- char * tmp;
mdns_txt_linked_item_t * txt = service->txt;
while (txt) {
- if (asprintf(&tmp, "%s%s%.*s", txt->key, txt->value ? "=" : "", txt->value_len, txt->value) > 0) {
- uint8_t l = _mdns_append_string(packet, index, tmp);
- free(tmp);
- if (!l) {
- return 0;
- }
+ int l = append_one_txt_record_entry(packet, index, txt);
+ if (l > 0) {
data_len += l;
- } else {
- HOOK_MALLOC_FAILED;
- // continue
+ } else if (l == 0) { // TXT entry won't fit into the mdns packet
+ return 0;
}
txt = txt->next;
}
@@ -2574,17 +2599,10 @@ static int _mdns_check_txt_collision(mdns_service_t * service, const uint8_t * d
uint8_t ours[len];
uint16_t index = 0;
- char * tmp;
txt = service->txt;
while (txt) {
- if (asprintf(&tmp, "%s%s%.*s", txt->key, txt->value ? "=" : "", txt->value_len, txt->value) > 0) {
- _mdns_append_string(ours, &index, tmp);
- free(tmp);
- } else {
- HOOK_MALLOC_FAILED;
- // continue
- }
+ append_one_txt_record_entry(ours, &index, txt);
txt = txt->next;
}
