[U-Boot] [PATCH v6 17/27] sandbox: 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 v6: None
Changes in v5:
-Simplify sandbox eth driver by switching from int array to byte array
-Switch priv from packet buffer to a pointer to net_rx_packets[0]

Changes in v4:
-Removed checks on priv != NULL and added protection in uclass instead

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

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

 arch/sandbox/dts/sandbox.dts |   1 +
 drivers/net/sandbox.c        | 107 +++++++++++++++++++++++++++++++++++++++++++
 include/configs/sandbox.h    |   1 +
 3 files changed, 109 insertions(+)

diff --git a/arch/sandbox/dts/sandbox.dts b/arch/sandbox/dts/sandbox.dts
index 36b3bd8..c2a3304 100644
--- a/arch/sandbox/dts/sandbox.dts
+++ b/arch/sandbox/dts/sandbox.dts
@@ -184,5 +184,6 @@
 	eth at 10002000 {
 		compatible = "sandbox,eth";
 		reg = <0x10002000 0x1000>;
+		fake-host-hwaddr = [00 00 66 44 22 00];
 	};
 };
diff --git a/drivers/net/sandbox.c b/drivers/net/sandbox.c
index 522990d..cb69a95 100644
--- a/drivers/net/sandbox.c
+++ b/drivers/net/sandbox.c
@@ -14,22 +14,128 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+/**
+ * struct eth_sandbox_priv - memory for sandbox mock driver
+ *
+ * fake_host_hwaddr: MAC address of mocked machine
+ * fake_host_ipaddr: IP address of mocked machine
+ * recv_packet_buffer: buffer of the packet returned as received
+ * recv_packet_length: length of the packet returned as received
+ */
+struct eth_sandbox_priv {
+	uchar fake_host_hwaddr[ARP_HLEN];
+	IPaddr_t fake_host_ipaddr;
+	uchar *recv_packet_buffer;
+	int recv_packet_length;
+};
+
 static int sb_eth_start(struct udevice *dev)
 {
+	struct eth_sandbox_priv *priv = dev_get_priv(dev);
+
 	debug("eth_sandbox: Start\n");
 
+	fdtdec_get_byte_array(gd->fdt_blob, dev->of_offset, "fake-host-hwaddr",
+			      priv->fake_host_hwaddr, ARP_HLEN);
+	priv->recv_packet_buffer = net_rx_packets[0];
 	return 0;
 }
 
 static int sb_eth_send(struct udevice *dev, void *packet, int length)
 {
+	struct eth_sandbox_priv *priv = dev_get_priv(dev);
+	struct ethernet_hdr *eth = packet;
+
 	debug("eth_sandbox: Send packet %d\n", length);
 
+	if (ntohs(eth->et_protlen) == PROT_ARP) {
+		struct arp_hdr *arp = packet + ETHER_HDR_SIZE;
+
+		if (ntohs(arp->ar_op) == ARPOP_REQUEST) {
+			struct ethernet_hdr *eth_recv;
+			struct arp_hdr *arp_recv;
+
+			/* store this as the assumed IP of the fake host */
+			priv->fake_host_ipaddr = NetReadIP(&arp->ar_tpa);
+			/* Formulate a fake response */
+			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);
+
+			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) {
+				struct ethernet_hdr *eth_recv;
+				struct ip_udp_hdr *ipr;
+				struct icmp_hdr *icmpr;
+
+				/* reply to the ping */
+				memcpy(priv->recv_packet_buffer, packet,
+				       length);
+				eth_recv = (void *)priv->recv_packet_buffer;
+				ipr = (void *)priv->recv_packet_buffer +
+					ETHER_HDR_SIZE;
+				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 = compute_ip_checksum(ipr,
+					IP_HDR_SIZE);
+
+				icmpr->type = ICMP_ECHO_REPLY;
+				icmpr->checksum = 0;
+				icmpr->checksum = compute_ip_checksum(icmpr,
+					ICMP_HDR_SIZE);
+
+				priv->recv_packet_length = length;
+			}
+		}
+	}
+
 	return 0;
 }
 
 static int sb_eth_recv(struct udevice *dev, uchar **packetp)
 {
+	struct eth_sandbox_priv *priv = dev_get_priv(dev);
+
+	if (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;
+		*packetp = priv->recv_packet_buffer;
+		return lcl_recv_packet_length;
+	}
 	return 0;
 }
 
@@ -80,5 +186,6 @@ U_BOOT_DRIVER(eth_sandbox) = {
 	.ofdata_to_platdata = 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),
 };
diff --git a/include/configs/sandbox.h b/include/configs/sandbox.h
index 664b984..9189f6a 100644
--- a/include/configs/sandbox.h
+++ b/include/configs/sandbox.h
@@ -126,6 +126,7 @@
 /* include default commands */
 #include <config_cmd_default.h>
 
+#define CONFIG_CMD_PING
 
 #define CONFIG_CMD_HASH
 #define CONFIG_HASH_VERIFY
-- 
1.7.11.5