Michael, What you do is correct, but apparently the ctl_enqueuedata() function is buggy. It creates an mbuf with you data but doesn't set the len of the mbuf. Using ctl_enqueuembuf() for the time being. I should just work fine. Christophe. On 10/18/02 4:16 PM, "Michael Cashwell" <mboards@prograde.net> wrote:
Greetings all,
I can almost talk with my NKE from userland but I'm having socket
problems. I can't get any data from the NKE.
I'm using the AF_SYSTEM domain from <sys/kern_control.h>. It
essentially is registering a protocol handler as a SOCK_DGRAM type.
Then from userland I do this (I've deleted the error checking code
below for brevity):
struct sockaddr_ctl sf;
memset(&sf, 0, sizeof(sf));
m_rpcSock = socket(AF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
sf.sc_len = sizeof(sf);
sf.sc_family = AF_SYSTEM;
sf.ss_sysaddr = AF_SYS_CONTROL;
sf.sc_id = A1_DARWIN_NKE_SIG;
sf.sc_unit = A1_NKE_UNIT_RPC;
connect(m_rpcSock, (struct sockaddr *)&sf, sizeof(sf);
This all works. I also successfully send one byte of data to the NKE
via:
char dummy = 0;
error = send(m_rpcSock, &dummy, 1, 0);
But then when the userland code call recv() with zero flags it blocks
forever. I then added this diagnostic loop just to verify and recv()
always returns -1 and EAGAIN:
do {
sleep(2);
error = recv(m_rpcSock, ver, sizeof(ver), MSG_DONTWAIT |
MSG_PEEK);
printf("version MSG_PEEK returned %08X, error %d\n", error,
errno);
} while (error != sizeof(ver));
But the log shows that the NKE does receive the one zero byte and in
response does this:
unsigned short ver[2];
ver[0] = IPC_VERSION;
ver[1] = IPC_MIN_SUPPORTED_VERSION;
error = ctl_enqueuedata(ctlref, ver, sizeof(ver), 0);
printf("RPC version send result = %d\n", error);
The log also shows that the ctl_enqueuedata() call returns zero. (I've
also verified that ctlref is the same one the NKE registered.) So it
should have written data to the socket. I can't figure out why the
userland code cannot receive anything.
I've done this sort of thing in the past using SOCK_RAW but the
infrastructure is forcing me to use SOCK_DGRAM. I expect this to raise
some issues in terms of how I read data from the socket but I can
handle that with MSG_PEEK. But only if I can get data to arrive. If
anyone's done this sort of socket code and could assist I'd appreciate
it.
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