* space and from the other side. The world is (sadly) configured to
* take in only Ethernet devices...
*
- * Because of this, currently there is an copy-each-rxed-packet
- * overhead on the RX path. Each IP packet has to be reallocated to
- * add an ethernet header (as there is no space in what we get from
- * the device). This is a known drawback and coming versions of the
- * device's firmware are being changed to add header space that can be
- * used to insert the ethernet header without having to reallocate and
- * copy.
+ * Because of this, when using firmwares <= v1.3, there is an
+ * copy-each-rxed-packet overhead on the RX path. Each IP packet has
+ * to be reallocated to add an ethernet header (as there is no space
+ * in what we get from the device). This is a known drawback and
+ * firmwares >= 1.4 add header space that can be used to insert the
+ * ethernet header without having to reallocate and copy.
*
* TX error handling is tricky; because we have to FIFO/queue the
* buffers for transmission (as the hardware likes it aggregated), we
* i2400m_tx_timeout Called when the device times out
*
* i2400m_net_rx Called by the RX code when a data frame is
- * available.
+ * available (firmware <= 1.3)
+ * i2400m_net_erx Called by the RX code when a data frame is
+ * available (firmware >= 1.4).
* i2400m_netdev_setup Called to setup all the netdev stuff from
* alloc_netdev.
*/
* Create a fake ethernet header
*
* For emulating an ethernet device, every received IP header has to
- * be prefixed with an ethernet header.
- *
- * What we receive has (potentially) many IP packets concatenated with
- * no ETH_HLEN bytes prefixed. Thus there is no space for an eth
- * header.
- *
- * We would have to reallocate or do ugly fragment tricks in order to
- * add it.
- *
- * But what we do is use the header space of the RX transaction
- * (*msg_hdr) as we don't need it anymore; then we'll point all the
- * data skbs there, as they share the same backing store.
- *
- * We only support IPv4 for v3 firmware.
+ * be prefixed with an ethernet header. Fake it with the given
+ * protocol.
*/
static
void i2400m_rx_fake_eth_header(struct net_device *net_dev,
- void *_eth_hdr)
+ void *_eth_hdr, __be16 protocol)
{
struct ethhdr *eth_hdr = _eth_hdr;
memcpy(eth_hdr->h_dest, net_dev->dev_addr, sizeof(eth_hdr->h_dest));
memset(eth_hdr->h_source, 0, sizeof(eth_hdr->h_dest));
- eth_hdr->h_proto = cpu_to_be16(ETH_P_IP);
+ eth_hdr->h_proto = protocol;
}
* @buf: pointer to the buffer containing the data
* @len: buffer's length
*
+ * This is only used now for the v1.3 firmware. It will be deprecated
+ * in >= 2.6.31.
+ *
+ * Note that due to firmware limitations, we don't have space to add
+ * an ethernet header, so we need to copy each packet. Firmware
+ * versions >= v1.4 fix this [see i2400m_net_erx()].
+ *
* We just clone the skb and set it up so that it's skb->data pointer
* points to "buf" and it's length.
*
memcpy(skb_put(skb, buf_len), buf, buf_len);
}
i2400m_rx_fake_eth_header(i2400m->wimax_dev.net_dev,
- skb->data - ETH_HLEN);
+ skb->data - ETH_HLEN,
+ cpu_to_be16(ETH_P_IP));
skb_set_mac_header(skb, -ETH_HLEN);
skb->dev = i2400m->wimax_dev.net_dev;
skb->protocol = htons(ETH_P_IP);
i2400m, buf, buf_len);
}
+
+/*
+ * i2400m_net_erx - pass a network packet to the stack (extended version)
+ *
+ * @i2400m: device descriptor
+ * @skb: the skb where the packet is - the skb should be set to point
+ * at the IP packet; this function will add ethernet headers if
+ * needed.
+ * @cs: packet type
+ *
+ * This is only used now for firmware >= v1.4. Note it is quite
+ * similar to i2400m_net_rx() (used only for v1.3 firmware).
+ *
+ * This function is normally run from a thread context. However, we
+ * still use netif_rx() instead of netif_receive_skb() as was
+ * recommended in the mailing list. Reason is in some stress tests
+ * when sending/receiving a lot of data we seem to hit a softlock in
+ * the kernel's TCP implementation [aroudn tcp_delay_timer()]. Using
+ * netif_rx() took care of the issue.
+ *
+ * This is, of course, still open to do more research on why running
+ * with netif_receive_skb() hits this softlock. FIXME.
+ */
+void i2400m_net_erx(struct i2400m *i2400m, struct sk_buff *skb,
+ enum i2400m_cs cs)
+{
+ struct net_device *net_dev = i2400m->wimax_dev.net_dev;
+ struct device *dev = i2400m_dev(i2400m);
+ int protocol;
+
+ d_fnstart(2, dev, "(i2400m %p skb %p [%u] cs %d)\n",
+ i2400m, skb, skb->len, cs);
+ switch(cs) {
+ case I2400M_CS_IPV4_0:
+ case I2400M_CS_IPV4:
+ protocol = ETH_P_IP;
+ i2400m_rx_fake_eth_header(i2400m->wimax_dev.net_dev,
+ skb->data - ETH_HLEN,
+ cpu_to_be16(ETH_P_IP));
+ skb_set_mac_header(skb, -ETH_HLEN);
+ skb->dev = i2400m->wimax_dev.net_dev;
+ skb->protocol = htons(ETH_P_IP);
+ net_dev->stats.rx_packets++;
+ net_dev->stats.rx_bytes += skb->len;
+ break;
+ default:
+ dev_err(dev, "ERX: BUG? CS type %u unsupported\n", cs);
+ goto error;
+
+ }
+ d_printf(3, dev, "ERX: receiving %d bytes to the network stack\n",
+ skb->len);
+ d_dump(4, dev, skb->data, skb->len);
+ netif_rx_ni(skb); /* see notes in function header */
+error:
+ d_fnend(2, dev, "(i2400m %p skb %p [%u] cs %d) = void\n",
+ i2400m, skb, skb->len, cs);
+}
+
static const struct net_device_ops i2400m_netdev_ops = {
.ndo_open = i2400m_open,
.ndo_stop = i2400m_stop,
git.openpandora.org / pandora-kernel.git / blobdiff