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[0/1] net: wget: fix TCP sequence number wrap around issue

Message ID 20240415130013.26721-1-yasuharu.shibata@gmail.com
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Series net: wget: fix TCP sequence number wrap around issue | expand

Message

Yasuharu Shibata April 15, 2024, 1 p.m. UTC 
Hi,

I send a patch fixing the wget issue.
There is a wrap around issue as already mentioned in [1].

The log in [2] indicates the following packets.

- Success packet
Packets received 64368, Transfer Successful
Bytes transferred = 93198937 (58e1a59 hex)

- Failed packet
Packets received 64368, Transfer Successful
Bytes transferred = 26984682 (19bc0ea hex)

"Bytes transferred" are different, but "Packets received" are same.
First one output by net_boot_file_size that is assigned at store_block().
Second one output by packets that is incremented at wget_handler().
Those differences are caused by the following line.
If tcp_seq_num is wrap around, store_block() isn't called.

```
static void wget_handler(uchar *pkt, u16 dport,
...
                if (tcp_seq_num >= initial_data_seq_num &&
                    store_block(pkt, tcp_seq_num - initial_data_seq_num,
                                len) != 0) {
                        wget_fail("wget: store error\n",
                                  tcp_seq_num, tcp_ack_num, action);
                        net_set_state(NETLOOP_FAIL);
                        return;
                }
```

I reproduced the issue and fixed it with the following patch.
Please check this patch.
I will recommend to apply patch in [3] with this patch,
if packets may drop.

[1]: https://lore.kernel.org/u-boot/CAOf5uwmb0vJOwSj81KvfWpK6yobyz0Ozm5vDGCa9K0rZejbZLA@mail.gmail.com/
[2]: https://lore.kernel.org/u-boot/CAJ+vNU2U9W2NRT6hf1CAEQ_56SDQviUEzuDD1iYOpdf1CNaZBw@mail.gmail.com/
[3]: https://lore.kernel.org/u-boot/20240414104607.5966-1-yasuharu.shibata@gmail.com/

Yasuharu Shibata (1):
  net: wget: fix TCP sequence number wrap around issue

 net/wget.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)