[U-Boot] [RFC PATCH v3 09/14] dm: eth: Add ARP and PING response to sandbox driver

[Joe Hershberger]

The sandbox driver will now generate response traffic to exercise the
ping command even when no network exists.  This allows the basic data
pathways of the DM to be tested.

Signed-off-by: Joe Hershberger <joe.hershberger at ni.com>
Reviewed-by: Simon Glass <sjg at chromium.org>
---

Changes in v3:
-Prevent a crash if memory is not allocated

Changes in v2:
-Change printfs to debug in sandbox driver
-Move static data to priv
-Move fake hwaddr to the device tree

 arch/sandbox/dts/sandbox.dts |   1 +
 drivers/net/sandbox.c        | 101 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+)

diff --git a/arch/sandbox/dts/sandbox.dts b/arch/sandbox/dts/sandbox.dts
index 502eb3d..ba635e8 100644
--- a/arch/sandbox/dts/sandbox.dts
+++ b/arch/sandbox/dts/sandbox.dts
@@ -186,5 +186,6 @@
 	eth at 10002000 {
 		compatible = "sandbox,eth";
 		reg = <0x10002000 0x1000>;
+		fake-host-hwaddr = <0x00 0x00 0x66 0x44 0x22 0x00>;
 	};
 };
diff --git a/drivers/net/sandbox.c b/drivers/net/sandbox.c
index 2a2ad41..f9fa1a1 100644
--- a/drivers/net/sandbox.c
+++ b/drivers/net/sandbox.c
@@ -15,22 +15,121 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+struct eth_sandbox_priv {
+	uchar fake_host_hwaddr[ARP_HLEN];
+	IPaddr_t fake_host_ipaddr;
+	uchar recv_packet_buffer[PKTSIZE];
+	int recv_packet_length;
+};
+
 static int sb_eth_init(struct udevice *dev, bd_t *bis)
 {
 	debug("eth_sandbox: Init\n");
 
+	struct eth_sandbox_priv *priv = dev->priv;
+	u32 int_array[ARP_HLEN];
+	int i;
+
+	if (!priv)
+		return -EINVAL;
+
+	fdtdec_get_int_array(gd->fdt_blob, dev->of_offset, "fake-host-hwaddr",
+			     int_array, ARP_HLEN);
+	for (i = 0; i < ARP_HLEN; i++)
+		priv->fake_host_hwaddr[i] = (uchar)int_array[i];
+
 	return 0;
 }
 
 static int sb_eth_send(struct udevice *dev, void *packet, int length)
 {
 	debug("eth_sandbox: Send packet %d\n", length);
+	struct eth_sandbox_priv *priv = dev->priv;
+	struct ethernet_hdr *eth = packet;
+
+	if (ntohs(eth->et_protlen) == PROT_ARP) {
+		struct arp_hdr *arp = packet + ETHER_HDR_SIZE;
+		if (ntohs(arp->ar_op) == ARPOP_REQUEST) {
+			/* store this as the assumed IP of the fake host */
+			priv->fake_host_ipaddr = NetReadIP(&arp->ar_tpa);
+			/* Formulate a fake response */
+			struct ethernet_hdr *eth_recv =
+				(void *)priv->recv_packet_buffer;
+			memcpy(eth_recv->et_dest, eth->et_src, ARP_HLEN);
+			memcpy(eth_recv->et_src, priv->fake_host_hwaddr,
+			       ARP_HLEN);
+			eth_recv->et_protlen = htons(PROT_ARP);
+
+			struct arp_hdr *arp_recv =
+				(void *)priv->recv_packet_buffer +
+				ETHER_HDR_SIZE;
+			arp_recv->ar_hrd = htons(ARP_ETHER);
+			arp_recv->ar_pro = htons(PROT_IP);
+			arp_recv->ar_hln = ARP_HLEN;
+			arp_recv->ar_pln = ARP_PLEN;
+			arp_recv->ar_op = htons(ARPOP_REPLY);
+			memcpy(&arp_recv->ar_sha, priv->fake_host_hwaddr,
+			       ARP_HLEN);
+			NetWriteIP(&arp_recv->ar_spa, priv->fake_host_ipaddr);
+			memcpy(&arp_recv->ar_tha, &arp->ar_sha, ARP_HLEN);
+			NetCopyIP(&arp_recv->ar_tpa, &arp->ar_spa);
+
+			priv->recv_packet_length = ETHER_HDR_SIZE +
+				ARP_HDR_SIZE;
+		}
+	} else if (ntohs(eth->et_protlen) == PROT_IP) {
+		struct ip_udp_hdr *ip = packet + ETHER_HDR_SIZE;
+		if (ip->ip_p == IPPROTO_ICMP) {
+			struct icmp_hdr *icmp = (struct icmp_hdr *)&ip->udp_src;
+			if (icmp->type == ICMP_ECHO_REQUEST) {
+				/* reply to the ping */
+				memcpy(priv->recv_packet_buffer, packet,
+				       length);
+				struct ethernet_hdr *eth_recv =
+					(void *)priv->recv_packet_buffer;
+				struct ip_udp_hdr *ipr =
+					(void *)priv->recv_packet_buffer +
+					ETHER_HDR_SIZE;
+				struct icmp_hdr *icmpr =
+					(struct icmp_hdr *)&ipr->udp_src;
+				memcpy(eth_recv->et_dest, eth->et_src,
+				       ARP_HLEN);
+				memcpy(eth_recv->et_src, priv->fake_host_hwaddr,
+				       ARP_HLEN);
+				ipr->ip_sum = 0;
+				ipr->ip_off = 0;
+				NetCopyIP((void *)&ipr->ip_dst, &ip->ip_src);
+				NetWriteIP((void *)&ipr->ip_src,
+					   priv->fake_host_ipaddr);
+				ipr->ip_sum = ~NetCksum((uchar *)ipr,
+					IP_HDR_SIZE >> 1);
+
+				icmpr->type = ICMP_ECHO_REPLY;
+				icmpr->checksum = 0;
+				icmpr->checksum = ~NetCksum((uchar *)icmpr,
+					(length - ETHER_HDR_SIZE -
+						IP_HDR_SIZE) >> 1);
+
+				priv->recv_packet_length = length;
+			}
+		}
+	}
 
 	return 0;
 }
 
 static int sb_eth_recv(struct udevice *dev)
 {
+	struct eth_sandbox_priv *priv = dev->priv;
+
+	if (priv && priv->recv_packet_length) {
+		int lcl_recv_packet_length = priv->recv_packet_length;
+		debug("eth_sandbox: received packet %d\n",
+		      priv->recv_packet_length);
+		priv->recv_packet_length = 0;
+		NetReceive((void *)priv->recv_packet_buffer,
+			   lcl_recv_packet_length);
+	}
 	return 0;
 }
 
@@ -42,6 +141,7 @@ static void sb_eth_halt(struct udevice *dev)
 static int sb_eth_write_hwaddr(struct udevice *dev)
 {
 	struct eth_pdata *pdata = dev->platdata;
+
 	debug("eth_sandbox %s: Write HW ADDR - %pM\n", dev->name,
 	      pdata->enetaddr);
 	return 0;
@@ -82,5 +182,6 @@ U_BOOT_DRIVER(eth_sandbox) = {
 	.ofdata_to_platdata = of_match_ptr(sb_eth_ofdata_to_platdata),
 	.remove	= sb_eth_remove,
 	.ops	= &sb_eth_ops,
+	.priv_auto_alloc_size = sizeof(struct eth_sandbox_priv),
 	.platdata_auto_alloc_size = sizeof(struct eth_pdata),
 };
-- 
1.7.11.5