When a task needs to send data, a callback is allocated and the
transmission is happening in a worker task through devif_send.
Synchronization between the two tasks (sender & worker) is
achieved by a semaphore.
If devif_send fails, this semaphore was never posted, leaving
the sending task blocked indefinitely. This commit fixes this
by checking the return code of netif_send, and posting this
semaphore in case of failure.
Polling then stops, and execution is resumed on the sending
task.
Regression by:
| commit 7fce145b30
| Author: chao an <anchao@xiaomi.com>
| Date: Mon Jan 30 21:36:39 2023 +0800
|
| net/devif: check the net device before use
|
| Signed-off-by: chao an <anchao@xiaomi.com>
Signed-off-by: chao an <anchao@xiaomi.com>
Allocate the device buffer only if the protocol really need to send data.
not all protocols require the driver to prepare additional iob before
sending, especially UDP, each iob reserves l2/l3 header in advance
after prepare write buffer, net device could reuse this entry to send directly
Signed-off-by: chao an <anchao@xiaomi.com>
This makes the user interface a little hostile. People thing of an MTU of 1500 bytes, but the corresponding packet is really 1514 bytes (including the 14 byte Ethernet header). A more friendly solution would configure the MTU (as before), but then derive the packet buffer size by adding the MAC header length. Instead, we define the packet buffer size then derive the MTU.
The MTU is not common currency in networking. On the wire, the only real issue is the MSS which is derived from MTU by subtracting the IP header and TCP header sizes (for the case of TCP). Now it is derived for the PKTSIZE by subtracting the IP header, the TCP header, and the MAC header sizes. So we should be all good and without the recurring 14 byte error in MTU's and MSS's.
Squashed commit of the following:
Trivial update to fix some spacing issues.
net/: Rename several macros containing _MTU to _PKTSIZE.
net/: Rename CONFIG_NET_SLIP_MTU to CONFIG_NET_SLIP_PKTSIZE and similarly for CONFIG_NET_TUN_MTU. These are not the MTU which does not include the size of the link layer header. These are the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename CONFIG_NET_6LOWPAN_MTU to CONFIG_NET_6LOWPAN_PKTSIZE and similarly for CONFIG_NET_TUN_MTU. These are not the MTU which does not include the size of the link layer header. These are the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename CONFIG_NET_ETH_MTU to CONFIG_NET_ETH_PKTSIZE. This is not the MTU which does not include the size of the link layer header. This is the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename the file d_mtu in the network driver structure to d_pktsize. That value saved there is not the MTU. The packetsize is the memory large enough to hold the maximum packet PLUS the size of the link layer header. The MTU does not include the link layer header.
