+/**
+ * send_ext_msg_udp - send extended log message to target
+ * @nt: target to send message to
+ * @msg: extended log message to send
+ * @msg_len: length of message
+ *
+ * Transfer extended log @msg to @nt. If @msg is longer than
+ * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
+ * ncfrag header field added to identify them.
+ */
+static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
+ int msg_len)
+{
+ static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
+ const char *header, *body;
+ int offset = 0;
+ int header_len, body_len;
+
+ if (msg_len <= MAX_PRINT_CHUNK) {
+ netpoll_send_udp(&nt->np, msg, msg_len);
+ return;
+ }
+
+ /* need to insert extra header fields, detect header and body */
+ header = msg;
+ body = memchr(msg, ';', msg_len);
+ if (WARN_ON_ONCE(!body))
+ return;
+
+ header_len = body - header;
+ body_len = msg_len - header_len - 1;
+ body++;
+
+ /*
+ * Transfer multiple chunks with the following extra header.
+ * "ncfrag=<byte-offset>/<total-bytes>"
+ */
+ memcpy(buf, header, header_len);
+
+ while (offset < body_len) {
+ int this_header = header_len;
+ int this_chunk;
+
+ this_header += scnprintf(buf + this_header,
+ sizeof(buf) - this_header,
+ ",ncfrag=%d/%d;", offset, body_len);
+
+ this_chunk = min(body_len - offset,
+ MAX_PRINT_CHUNK - this_header);
+ if (WARN_ON_ONCE(this_chunk <= 0))
+ return;
+
+ memcpy(buf + this_header, body + offset, this_chunk);
+
+ netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
+
+ offset += this_chunk;
+ }
+}
+
+static void write_ext_msg(struct console *con, const char *msg,
+ unsigned int len)
+{
+ struct netconsole_target *nt;
+ unsigned long flags;
+
+ if ((oops_only && !oops_in_progress) || list_empty(&target_list))
+ return;
+
+ spin_lock_irqsave(&target_list_lock, flags);
+ list_for_each_entry(nt, &target_list, list)
+ if (nt->extended && nt->enabled && netif_running(nt->np.dev))
+ send_ext_msg_udp(nt, msg, len);
+ spin_unlock_irqrestore(&target_list_lock, flags);
+}
+