[PATCH] net: lwip: support syslog

LOG_SYSLOG depends on NET, but the raw Ethernet and UDP header
builders it uses are only available with the legacy network stack. This
makes LOG_SYSLOG fail to build with NET_LWIP.

Provide lwIP implementations using the selected Ethernet device and its
indexed IP address from the environment. Move the shared declarations to
net-common.h and extend the syslog test to check the source MAC address
and IPv4 header checksum.

Signed-off-by: James Hilliard <[email protected]>
---
 include/net-common.h   |  7 ++++++
 include/net-legacy.h   |  4 ----
 net/lwip/net-lwip.c    | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 test/log/syslog_test.c |  2 ++
 test/log/syslog_test.h |  4 ++--
 5 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/include/net-common.h b/include/net-common.h
index 0c260873c2c..3084a2b2a57 100644
--- a/include/net-common.h
+++ b/include/net-common.h
@@ -362,6 +362,13 @@ struct ethernet_hdr {
 /* Ethernet header size */
 #define ETHER_HDR_SIZE	(sizeof(struct ethernet_hdr))
 
+/* Set Ethernet header; returns the size of the header */
+int net_set_ether(uchar *xet, const uchar *dest_ethaddr, uint prot);
+
+/* Set IPv4 and UDP headers */
+void net_set_udp_header(uchar *pkt, struct in_addr dest, int dport,
+			int sport, int len);
+
 /**
  * net_random_ethaddr - Generate software assigned random Ethernet address
  * @addr: Pointer to a six-byte array containing the Ethernet address
diff --git a/include/net-legacy.h b/include/net-legacy.h
index d3b122c9062..d7f55d34a30 100644
--- a/include/net-legacy.h
+++ b/include/net-legacy.h
@@ -344,15 +344,11 @@ int net_loop(enum proto_t);
 /* Get size of the ethernet header when we send */
 int net_eth_hdr_size(void);
 
-/* Set ethernet header; returns the size of the header */
-int net_set_ether(uchar *xet, const uchar *dest_ethaddr, uint prot);
 int net_update_ether(struct ethernet_hdr *et, uchar *addr, uint prot);
 
 /* Set IP header */
 void net_set_ip_header(uchar *pkt, struct in_addr dest, struct in_addr source,
 		       u16 pkt_len, u8 proto);
-void net_set_udp_header(uchar *pkt, struct in_addr dest, int dport,
-			int sport, int len);
 
 /* Callbacks */
 rxhand_f *net_get_udp_handler(void);	/* Get UDP RX packet handler */
diff --git a/net/lwip/net-lwip.c b/net/lwip/net-lwip.c
index 8f8f9d69020..4dd8f0d2ce7 100644
--- a/net/lwip/net-lwip.c
+++ b/net/lwip/net-lwip.c
@@ -159,6 +159,64 @@ static int get_udev_ipv4_info(struct udevice *dev, ip4_addr_t *ip,
 	return 0;
 }
 
+int net_set_ether(uchar *xet, const uchar *dest_ethaddr, uint prot)
+{
+	struct ethernet_hdr *et = (struct ethernet_hdr *)xet;
+	const uchar *src = eth_get_ethaddr();
+
+	memcpy(et->et_dest, dest_ethaddr, ARP_HLEN);
+	if (src)
+		memcpy(et->et_src, src, ARP_HLEN);
+	else
+		memset(et->et_src, 0, ARP_HLEN);
+	et->et_protlen = htons(prot);
+
+	return ETHER_HDR_SIZE;
+}
+
+static void net_lwip_set_ip_header(uchar *pkt, struct in_addr dest,
+				   struct in_addr source, u16 pkt_len,
+				   u8 proto)
+{
+	static u16 ip_id;
+	struct ip_udp_hdr *ip = (struct ip_udp_hdr *)pkt;
+
+	ip->ip_hl_v = 0x45;
+	ip->ip_tos = 0;
+	ip->ip_len = htons(pkt_len);
+	ip->ip_p = proto;
+	ip->ip_id = htons(ip_id++);
+	ip->ip_off = htons(IP_FLAGS_DFRAG);
+	ip->ip_ttl = 255;
+	ip->ip_sum = 0;
+	memcpy(&ip->ip_src, &source, sizeof(source));
+	memcpy(&ip->ip_dst, &dest, sizeof(dest));
+	ip->ip_sum = compute_ip_checksum(ip, IP_HDR_SIZE);
+}
+
+void net_set_udp_header(uchar *pkt, struct in_addr dest, int dport, int sport,
+			int len)
+{
+	struct ip_udp_hdr *ip = (struct ip_udp_hdr *)pkt;
+	struct in_addr source = {};
+	ip4_addr_t addr, mask, gateway;
+	struct udevice *dev = eth_get_dev();
+	u16 pkt_len = IP_UDP_HDR_SIZE + len;
+
+	if (len & 1)
+		pkt[IP_UDP_HDR_SIZE + len] = 0;
+
+	if (dev && !get_udev_ipv4_info(dev, &addr, &mask, &gateway))
+		source.s_addr = addr.addr;
+
+	net_lwip_set_ip_header(pkt, dest, source, pkt_len, IPPROTO_UDP);
+
+	ip->udp_src = htons(sport);
+	ip->udp_dst = htons(dport);
+	ip->udp_len = htons(UDP_HDR_SIZE + len);
+	ip->udp_xsum = 0;
+}
+
 /*
  * Initialize DNS via env
  */
diff --git a/test/log/syslog_test.c b/test/log/syslog_test.c
index b6c0631aaf6..f848506fb1c 100644
--- a/test/log/syslog_test.c
+++ b/test/log/syslog_test.c
@@ -34,11 +34,13 @@ int sb_log_tx_handler(struct udevice *dev, void *packet, unsigned int len)
 
 	/* Check Ethernet header */
 	ut_asserteq_mem(&eth_hdr->et_dest, net_bcast_ethaddr, ARP_HLEN);
+	ut_asserteq_mem(&eth_hdr->et_src, eth_get_ethaddr(), ARP_HLEN);
 	ut_asserteq(ntohs(eth_hdr->et_protlen), PROT_IP);
 
 	/* Check IP header */
 	buf += sizeof(struct ethernet_hdr);
 	ip_udp_hdr = (struct ip_udp_hdr *)buf;
+	ut_assert(ip_checksum_ok(ip_udp_hdr, IP_HDR_SIZE));
 	ut_asserteq(ip_udp_hdr->ip_p, IPPROTO_UDP);
 	ut_asserteq(ip_udp_hdr->ip_dst.s_addr, 0xffffffff);
 	ut_asserteq(ntohs(ip_udp_hdr->udp_dst), 514);
diff --git a/test/log/syslog_test.h b/test/log/syslog_test.h
index 39cce4ed498..89c86541f5e 100644
--- a/test/log/syslog_test.h
+++ b/test/log/syslog_test.h
@@ -31,8 +31,8 @@ struct sb_log_env {
  *
  * The following checks are executed:
  *
- * * the Ethernet packet indicates a IP broadcast message
- * * the IP header is for a local UDP broadcast message to port 514
+ * * the Ethernet packet uses the selected interface and broadcast destination
+ * * the IP header checksum is valid and describes a UDP broadcast to port 514
  * * the UDP payload matches the expected string
  *
  * After testing the pointer to the expected string is set to NULL to signal

---
base-commit: 964ad5b5c91b7be56e443e899d7f873e6aa8c9fc
change-id: 20260825-lwip-syslog-v1-a5625eba2ea3

Best regards,
--  
James Hilliard <[email protected]>