gld, gldm_reset, gldm_start, gldm_stop, gldm_set_mac_addr,
gldm_set_multicast, gldm_set_promiscuous, gldm_send, gldm_intr,
gldm_get_stats, gldm_ioctl - Generic LAN Driver entry points
int prefix_reset(gld_mac_info_t *macinfo);
int prefix_start(gld_mac_info_t *macinfo);
int prefix_stop(gld_mac_info_t *
int prefix_set_mac_addr(gld_mac_info_t *
macinfo, unsigned char *macaddr);
int prefix_set_multicast(gld_mac_info_t *
macinfo, unsigned char *multicastaddr,
int prefix_set_promiscuous(gld_mac_info_t *macinfo,
int prefix_send(gld_mac_info_t *macinfo,
uint_t prefix_intr(gld_mac_info_t *macinfo);
int prefix_get_stats(gld_mac_info_t *macinfo,
struct gld_stats *stats);
int prefix_ioctl(gld_mac_info_t *macinfo,
queue_t *q, mblk_t *mp);
Solaris architecture specific (Solaris DDI).
Pointer to a gld_mac_info(9S) structure.
Pointer to the beginning of a character array con‐
taining a valid MAC address. The array will be of
the length specified by the driver in the
gldm_addrlen element of the gld_mac_info(9S) struc‐
Pointer to the beginning of a character array con‐
taining a multicast, group, or functional address.
The array will be of the length specified by the
driver in the gldm_addrlen element of the
A flag indicating whether reception of the multicast
address is to be enabled or disabled. This argument
is specified as GLD_MULTI_ENABLE or GLD_MULTI_DIS‐
A flag indicating what type of promiscuous mode, if
any, is to be enabled. This argument is specified as
GLD_MAC_PROMISC_PHYS, GLD_MAC_PROMISC_MULTI, or
Pointer to a STREAMS message block containing the
packet to be transmitted or the ioctl to be executed.
Pointer to a gld_stats(9S) structure to be filled in
with the current values of statistics counters.
Pointer to the queue(9S) structure to be used in the
reply to the ioctl.
These entry points must be implemented by a device-specific network
driver designed to interface with the Generic LAN Driver (GLD).
As described in gld(7D), the main data structure for communication
between the device-specific driver and the GLD module is the
gld_mac_info(9S) structure. Some of the elements in that structure are
function pointers to the entry points described here. The device-spe‐
cific driver must, in its attach(9E) routine, initialize these function
pointers before calling gld_register().
gldm_reset() resets the hardware to its initial state.
gldm_start() enables the device to generate interrupts and prepares the
driver to call gld_recv() for delivering received data packets to GLD.
gldm_stop() disables the device from generating any interrupts and
stops the driver from calling gld_recv() for delivering data packets to
GLD. GLD depends on the gldm_stop() routine to ensure that the device
will no longer interrupt, and it must do so without fail.
gldm_set_mac_addr() sets the physical address that the hardware is to
use for receiving data. This function should program the device to the
passed MAC address macaddr.
gldm_set_multicast() enables and disables device-level reception of
specific multicast addresses. If the third argument multiflag is set to
GLD_MULTI_ENABLE, then the function sets the interface to receive pack‐
ets with the multicast address pointed to by the second argument; if
multiflag is set to GLD_MULTI_DISABLE, the driver is allowed to disable
reception of the specified multicast address.
This function is called whenever GLD wants to enable or disable recep‐
tion of a multicast, group, or functional address. GLD makes no assump‐
tions about how the device does multicast support and calls this func‐
tion to enable or disable a specific multicast address. Some devices
may use a hash algorithm and a bitmask to enable collections of multi‐
cast addresses; this is allowed, and GLD will filter out any superflu‐
ous packets that are not required. If disabling an address could result
in disabling more than one address at the device level, it is the
responsibility of the device driver to keep whatever information it
needs to avoid disabling an address that GLD has enabled but not dis‐
gldm_set_multicast() will not be called to enable a particular multi‐
cast address that is already enabled, nor to disable an address that is
not currently enabled. GLD keeps track of multiple requests for the
same multicast address and only calls the driver's entry point when the
first request to enable, or the last request to disable a particular
multicast address is made.
gldm_set_promiscuous() enables and disables promiscuous mode. This
function is called whenever GLD wants to enable or disable the recep‐
tion of all packets on the medium, or all multicast packets on the
medium. If the second argument promiscflag is set to the value of
GLD_MAC_PROMISC_PHYS, then the function enables physical-level promis‐
cuous mode, resulting in the reception of all packets on the medium. If
promiscflag is set to GLD_MAC_PROMISC_MULTI, then reception of all mul‐
ticast packets will be enabled. If promiscflag is set to
GLD_MAC_PROMISC_NONE, then promiscuous mode is disabled.
In the case of a request for promiscuous multicast mode, drivers for
devices that have no multicast-only promiscuous mode must set the
device to physical promiscuous mode to ensure that all multicast pack‐
ets are received. In this case the routine should return GLD_SUCCESS.
The GLD software will filter out any superfluous packets that are not
For forward compatibility, gldm_set_promiscuous() routines should treat
any unrecognized values for promiscflag as though they were
gldm_send() queues a packet to the device for transmission. This rou‐
tine is passed a STREAMS message containing the packet to be sent. The
message may comprise multiple message blocks, and the send routine must
chain through all the message blocks in the message to access the
entire packet to be sent. The driver should be prepared to handle and
skip over any zero-length message continuation blocks in the chain. The
driver should check to ensure that the packet does not exceed the maxi‐
mum allowable packet size, and must pad the packet, if necessary, to
the minimum allowable packet size. If the send routine successfully
transmits or queues the packet, it should return GLD_SUCCESS.
The send routine should return GLD_NORESOURCES if it cannot immediately
accept the packet for transmission; in this case GLD will retry it
later. If gldm_send() ever returns GLD_NORESOURCES, the driver must, at
a later time when resources have become available, call gld_sched() to
inform GLD that it should retry packets that the driver previously
failed to queue for transmission. (If the driver's gldm_stop() routine
is called, the driver is absolved from this obligation until it later
again returns GLD_NORESOURCES from its gldm_send() routine; however,
extra calls to gld_sched() will not cause incorrect operation.)
If the driver's send routine returns GLD_SUCCESS, then the driver is
responsible for freeing the message when the driver and the hardware no
longer need it. If the send routine copied the message into the device,
or into a private buffer, then the send routine may free the message
after the copy is made. If the hardware uses DMA to read the data
directly out of the message data blocks, then the driver must not free
the message until the hardware has completed reading the data. In this
case the driver will probably free the message in the interrupt rou‐
tine, or in a buffer-reclaim operation at the beginning of a future
send operation. If the send routine returns anything other than
GLD_SUCCESS, then the driver must not free the message.
gldm_intr() is called when the device might have interrupted. Since it
is possible to share interrupts with other devices, the driver must
check the device status to determine whether it actually caused an
interrupt. If the device that the driver controls did not cause the
interrupt, then this routine must return DDI_INTR_UNCLAIMED. Otherwise
it must service the interrupt and should return DDI_INTR_CLAIMED. If
the interrupt was caused by successful receipt of a packet, this rou‐
tine should put the received packet into a STREAMS message of type
M_DATA and pass that message to gld_recv().
gld_recv() will pass the inbound packet upstream to the appropriate
next layer of the network protocol stack. It is important to correctly
set the b_rptr and b_wptr members of the STREAMS message before calling
The driver should avoid holding mutex or other locks during the call to
gld_recv(). In particular, locks that could be taken by a transmit
thread may not be held during a call to gld_recv(): the interrupt
thread that calls gld_recv() may in some cases carry out processing
that includes sending an outgoing packet, resulting in a call to the
driver's gldm_send() routine. If the gldm_send() routine were to try to
acquire a mutex being held by the gldm_intr() routine at the time it
calls gld_recv(), this could result in a panic due to recursive mutex
The interrupt code should increment statistics counters for any errors.
This includes failure to allocate a buffer needed for the received data
and any hardware-specific errors such as CRC errors or framing errors.
gldm_get_stats() gathers statistics from the hardware and/or driver
private counters, and updates the gld_stats(9S) structure pointed to by
stats. This routine is called by GLD when it gets a request for statis‐
tics, and provides the mechanism by which GLD acquires device dependent
statistics from the driver before composing its reply to the statistics
request. See gld_stats(9S) and gld(7D) for a description of the defined
gldm_ioctl() implements any device-specific ioctl commands. This ele‐
ment may be specified as NULL if the driver does not implement any
ioctl functions. The driver is responsible for converting the message
block into an ioctl reply message and calling the qreply(9F) function
before returning GLD_SUCCESS. This function should always return
GLD_SUCCESS; any errors the driver may wish to report should be
returned via the message passed to qreply(9F). If the gldm_ioctl ele‐
ment is specified as NULL, GLD will return a message of type M_IOCNAK
with an error of EINVAL.
RETURN VALUESgldm_intr() must return:
if and only if the device definitely inter‐
if the device did not interrupt.
The other functions must return:
on success. gldm_stop() and gldm_ioctl() should
always return this value.
if there are insufficient resources to carry out
the request at this time. Only
gldm_set_promiscuous(), and gldm_send() may return
if gldm_send() is called when there is no physical
connection to a network or link partner.
if the requested function is not supported. Only
gldm_set_mac_addr(), gldm_set_multicast(), and
gldm_set_promiscuous() may return this value.
if the function detected an unsuitable argument,
for example, a bad multicast address, a bad MAC
address, or a bad packet or packet length.
on hardware failure.
SEE ALSOgld(7D), gld(9F), gld_mac_info(9S), gld_stats(9S), dlpi(7P),
Writing Device Drivers
Jan 3, 2001 GLD(9E)