This commit adds support to the netconn write APIs to take an input of
vectors instead of a single data pointer
This allows vectors sent on a TCP connection via sendmsg to be treated
atomically. The set of vectors is segmented into as much data as can
fit into the send buffer and then the TCP output function is called
Previously, each vector was passed to netconn_write_partly and tcp_write
segmented it into its own packet, which was then it was sent via
tcp_output (if not Nagleing)
This commit adds vector support to lwip_netconn_do_writemore() which
is the meat of the TCP write functionality from netconn/sockets layer.
A new netconn API netconn_write_vectors_partly() takes a set of vectors
as input and hooks up to do_writemore()
This commit also defines IOV_MAX because we are limited to only
supporting 65535 vectors due to choice of u16_t for the vector count
Create new function dhcp_release_and_stop() that stops DHCP statemachine and sends release message if needed. Also stops AUTOIP if in coop mode.
Old dhcp_release() and dhcp_stop() function internally call dhcp_release_and_stop() now.
lwIP aims to support zero-copy TX, and thus, must internally handle
all cases that pbufs are referenced rather than copied upon low-level
output. However, in the current situation, the arp/ndp packet queuing
routines conservatively copy entire packets, even when unnecessary in
cases where lwIP is used in a zero-copy compliant manner. This patch
moves the decision whether to copy into a centralized macro, allowing
zero-copy compliant applications to override the macro to avoid the
unnecessary copies. The macro defaults to the safe behavior, though.
This commit changes netconn_write_partly to use msg.w.offset to set
bytes_written for both blocking and non-blocking connections
This is correct because msg.w.offset is the canonical output from
the do_write call and in the case that not all bytes were written,
(a bug?) returning the full size to the caller is dangerous
Lastly, this commit adds an assert for the blocking case to sanity
check that all the bytes we requested were written. This will help
catch bugs in do_write
This commit makes a couple of cleanups discussed in patch #8882:
1) msg.w.offset should not be set to 0 in the error case. It is
only valid when err == ERR_OK
2) Remove out-of-date comment which indicated the entire write had
completed (not true for non-blocking write)
This also updates the documentation on offset to include that offset
is only valid when err == ERR_OK
Dirk Ziegelmeier
Joel Cunningham
goldsimon
Marco
David van Moolenbroek