[PATCH net-next v2 8/8] net: netconsole: append userdata to fragmented netconsole messages

From: Matthew Wood
Date: Fri Jan 26 2024 - 18:16:35 EST


Regardless of whether the original message body or formatted userdata
exceeds the MAX_PRINT_CHUNK, append userdata to the netconsole message
starting with the first chunk that has available space after writing the
body.

Co-developed-by: Breno Leitao <leitao@xxxxxxxxxx>
Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
Signed-off-by: Matthew Wood <thepacketgeek@xxxxxxxxx>
---
drivers/net/netconsole.c | 50 +++++++++++++++++++++++++++++-----------
1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index de668a0794b1..b33ceb110434 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1086,24 +1086,48 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
memcpy(buf + release_len, header, header_len);
header_len += release_len;

- while (offset < body_len) {
+ while (offset < body_len + userdata_len) {
int this_header = header_len;
- int this_chunk;
+ int this_offset = 0;
+ int this_chunk = 0;

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);
+ ",ncfrag=%d/%d;", offset,
+ body_len + userdata_len);
+
+ /* Not all body data has been written yet */
+ if (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);
+ this_offset += this_chunk;
+ }
+ /* Body is fully written and there is pending userdata to write,
+ * append userdata in this chunk
+ */
+ if (offset + this_offset >= body_len &&
+ offset + this_offset < userdata_len + body_len) {
+ int sent_userdata = (offset + this_offset) - body_len;
+ int preceding_bytes = this_chunk + this_header;
+
+ if (WARN_ON_ONCE(sent_userdata < 0))
+ return;
+
+ this_chunk = min(userdata_len - sent_userdata,
+ MAX_PRINT_CHUNK - preceding_bytes);
+ if (WARN_ON_ONCE(this_chunk <= 0))
+ return;
+ memcpy(buf + this_header + this_offset,
+ userdata + sent_userdata,
+ this_chunk);
+ this_offset += this_chunk;
+ }

- offset += this_chunk;
+ netpoll_send_udp(&nt->np, buf, this_header + this_offset);
+ offset += this_offset;
}
}

--
2.43.0