[U-Boot] [PATCH 1/1] net: Store waiting packet in a different buffer when making ARP requests

[Tran Tien Dat]

Currently, upon receiving an appropriate ARP reply, the packet in
net_tx_packet is sent. However, this is a common buffer used by other
protocol as well, so it may not be the original packet waiting to be sent
after ARP.

This patch repurposes another buffer, arp_tx_packet to store the waiting
packet and use the net_tx_packet to prepare ARP request.

Signed-off-by: Tran Tien Dat <peter.trantiendat at gmail.com>
---

 net/arp.c | 18 ++++++++++--------
 net/arp.h |  1 +
 net/net.c |  3 +++
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/net/arp.c b/net/arp.c
index b8a71684cd..f5e2c0b0cf 100644
--- a/net/arp.c
+++ b/net/arp.c
@@ -35,8 +35,8 @@ int		arp_wait_tx_packet_size;
 ulong		arp_wait_timer_start;
 int		arp_wait_try;
 
-static uchar   *arp_tx_packet;	/* THE ARP transmit packet */
-static uchar	arp_tx_packet_buf[PKTSIZE_ALIGN + PKTALIGN];
+uchar   *arp_wait_tx_packet;	/* THE waiting transmit packet after ARP */
+static uchar	arp_wait_tx_packet_buf[PKTSIZE_ALIGN + PKTALIGN];
 
 void arp_init(void)
 {
@@ -45,8 +45,8 @@ void arp_init(void)
 	net_arp_wait_packet_ip.s_addr = 0;
 	net_arp_wait_reply_ip.s_addr = 0;
 	arp_wait_tx_packet_size = 0;
-	arp_tx_packet = &arp_tx_packet_buf[0] + (PKTALIGN - 1);
-	arp_tx_packet -= (ulong)arp_tx_packet % PKTALIGN;
+	arp_wait_tx_packet = &arp_wait_tx_packet_buf[0] + (PKTALIGN - 1);
+	arp_wait_tx_packet -= (ulong)arp_wait_tx_packet % PKTALIGN;
 }
 
 void arp_raw_request(struct in_addr source_ip, const uchar *target_ethaddr,
@@ -58,7 +58,7 @@ void arp_raw_request(struct in_addr source_ip, const uchar *target_ethaddr,
 
 	debug_cond(DEBUG_DEV_PKT, "ARP broadcast %d\n", arp_wait_try);
 
-	pkt = arp_tx_packet;
+	pkt = net_tx_packet;
 
 	eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_ARP);
 	pkt += eth_hdr_size;
@@ -76,7 +76,7 @@ void arp_raw_request(struct in_addr source_ip, const uchar *target_ethaddr,
 	memcpy(&arp->ar_tha, target_ethaddr, ARP_HLEN);	/* target ET addr */
 	net_write_ip(&arp->ar_tpa, target_ip);		/* target IP addr */
 
-	net_send_packet(arp_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
+	net_send_packet(net_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
 }
 
 void arp_request(void)
@@ -217,9 +217,11 @@ void arp_receive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len)
 
 			/* set the mac address in the waiting packet's header
 			   and transmit it */
-			memcpy(((struct ethernet_hdr *)net_tx_packet)->et_dest,
+			memcpy(((struct ethernet_hdr *)arp_wait_tx_packet)
+					->et_dest,
 			       &arp->ar_sha, ARP_HLEN);
-			net_send_packet(net_tx_packet, arp_wait_tx_packet_size);
+			net_send_packet(arp_wait_tx_packet,
+					arp_wait_tx_packet_size);
 
 			/* no arp request pending now */
 			net_arp_wait_packet_ip.s_addr = 0;
diff --git a/net/arp.h b/net/arp.h
index afb86958f3..65d73927a7 100644
--- a/net/arp.h
+++ b/net/arp.h
@@ -20,6 +20,7 @@ extern uchar *arp_wait_packet_ethaddr;
 extern int arp_wait_tx_packet_size;
 extern ulong arp_wait_timer_start;
 extern int arp_wait_try;
+extern uchar *arp_wait_tx_packet;
 
 void arp_init(void);
 void arp_request(void);
diff --git a/net/net.c b/net/net.c
index f35695b4fc..6325ad3e1a 100644
--- a/net/net.c
+++ b/net/net.c
@@ -836,6 +836,9 @@ int net_send_udp_packet(uchar *ether, struct in_addr dest, int dport, int sport,
 
 		/* size of the waiting packet */
 		arp_wait_tx_packet_size = pkt_hdr_size + payload_len;
+		/* copy current packet to ARP waiting packet buffer */
+		memcpy(arp_wait_tx_packet, net_tx_packet,
+		       arp_wait_tx_packet_size);
 
 		/* and do the ARP request */
 		arp_wait_try = 1;
-- 
2.18.0